CHNG 1: M U1.1. C s nghin cu v mc ch ca lun vnWatermarking s l qu trnh nhng thng tin, hay mt watermark, vo trong mt i tng multimedia s, cng nh watermark c th c pht hin hay trch ra sau a ra s xc nhn v i tng. Watermarking chng t n l cng c ng tin cy cho bo v bn quyn v nhn thc cho cc phng tin s, v v vy c rt nhiu nghin cu v ang c thc hin trong lnh vc ny.Watermarking xut hin cch y hn 700 nm. Khi n l mt k thut c s dng bi cc nh sn xut giy nhn dng cc sn phm ca mnh. Ngy nay chng ta vn thng xuyn bt gp cc watermark trn giy, v d trn cc t tin giy, sc, tem bu in, v cc vn bn hnh chnh ca nh nc. Bn cnh cc ng dng trn giy, watermarking cng c th c s dng cung cc cc gii php an ninh cho cc d liu a phng tin s nh l m thanh, hnh nh, videoTrong phm vi ti ny, ti la chn k thut watermarking cho nh tnh nghin cu, phn tch v thc hin vi c hai loi watermarking hin v n.Mt ng dng rt c ngha v quan trng ca watermarking cho hnh nh l trongnhnthchnhnhuracacccameragimsthaybomt. Vic chuyn dch t tng t sang s trong lnh vc gim st hnh nh to ra mt l hng bo mt khi chng ta c gng cung cp cc bng chng hnh nh gim st ti php lut.Hnh nh gim st s khng th c chp nhn nh mt bng chng hp php bi v vic sa i d liu s l trc tip d dng, v s hin 1hu ca cc cng c x l nh lm cho s nhn thc l rt ng ng. c bit, n c th ph ri v gy nhiu cc video s m khng h li mt du vt no.Watermarking c th cung cp s nhn thc v pht hin ph ri cho cc h thng gim st s. Mt vi h thng hin ti cung cp cc la chn watermarking cho cc hnh nh lu tr. Cc h thng ny cho rng ng truyn dn t video camera ti trung tm lu tr l an ton v chng ch thc hin tp trung bo mt cho video khi trung tm lu tr. S tha nhn ny l khng ng nu h thng b tn cng tng truyn dn. Trong trng hp ny, nhn thc phi c thc hin ngay ti video camera cung cp mt h thng bo mt an ton hn. iu ny c th t c bng vic s dng mt thit b trn c s phn cng hay mm nhng mt watermark vo tn hiu video ti ngay video camera. V qu trnh nhng watermark yu cu tc v mnh, nn thc hin bng phn cng c l l cn thit v hp l hn.Ngy nay, cc chp FPGA ang ci thin ng k v tc , dung lng nh, s mm do, v s tiu hao nng lng theo tng nm. Cc ng dng m FPGA c th c ng dng bao gm x l tn hiu s, x l m thanh v hnh nh, my tnh s, nhn dng, bo mtCc ng dng m yu cu rt nhiu cc x l song song th rt hiu qu vi kin trc ca FPGA. Vi watermarking cho nh s th FPGA em li rt nhiu hiu qu bi kh nng x l song song mnh m ca n. Nhng hn tt c l gi thnh m FPGA mang li l rt hp l.V vy lun vn la chn FPGA nghin cu v thc hin pht trin cho thut ton watermarking cho nh s, vi mc ch ng gp chnh ca lun vn l:2 S phn tch khoa hc v cc vn lin quan n watermarking cho nh s nn. Cc kt qu m phng mc h thng khng nh tnh ng n v mnh m ca thut ton. Cc phn tch ti u thut ton cho vic thc hin trn phn cng c nghin cu v thc hin. Kho st nh gi v a ra cc ng dng quan trng ca watermarking trong cc lnh vc bo v bn quyn v nhn thc s, c bit ng dng cho cc h thng camera gim st v bo mt. Quy trnh thit k s v cc cng c s dng trong thit k v m phng khi thc hin trn FPGA.Cc kt qu c trnh by trong lun vn ny t c t cc thut ton c th trn cc thit b FPGA ca hng Xilinx. Tuy nhin chng mi ch dng li mc nghin cu v m phng ng thit k Co-design trn cc cng c pht trin ca hng Xilinx trn my tnh PC.1.2. T chc lun vnB cc ca ti c t chc thnh 5 chng nh sau: Chng 1: M u. Tc gi trnh by tm tt c s nghin cu v mc ch cng nh t chc ca lun vn. Chng 2: Tng quan v cc chun nn multimedia, watermarking v cc phng php m phng.Trong chng ny gii thiu tng quan v multimedia, nn d liu multimedia, cc phng php nh gi cht lng d liu v cht lng nn i vi cc thut ton nn. L thuyt 3watermarkingvcccngcsdngthchinvmphngcng c gii thiu trong chng ny. Chng 3: C s l thuyt ca cc k thut nn nh JPEGv Watermarking cho nh s. Trong chng ny tc gi trnh by v phn tch c s l thuyt ca cc thut ton v cc k thut lin quan n nn nhJPEG, watermarkingminDCTtrongminnnvminchann JPEG. Chng4: Phntchv xydngcckhi thut tonnnnhv watermarking. Chng ny tp trung phn tch cc thut ton nn nh v watermarking theo chiu su, t xy dng thit k cc khi m VHDL thc hin thut ton cho ng dng phn cng FPGA. Chng 5: Kt qu m phng v thc hin pht trin. Chng ny trnh by cc kt qu m phng m hnh mc h thng cho ton b thut ton da trn cng c Matlab/simulink, v cc kt qu thc hin cc thut ton trn VHDL v FPGA. T a ra nhn xt v kt lun4CHNG 2: TNG QUAN V CC CHUN NN MULTIMEDIA, WATERMARKING V CC PHNG PHP M PHNGHin nay trn th gii c nhiu cc chun nn d liu multimedia khc nhau. Mi chun nn s dng cc k thut ring v c trng cho cc ng dng khc nhau. Ging nh nn d liu multimedia, k thut watermarking cng c thc hin theo nhiu phng php, trong cc min lm vic khc nhau. V vy vic nh gi cc k thut ny l rt quan trng trong qu trnh nghin cu cng nh trong qu trnh thc hin. Trong chng ny, lun vn gii thiu tng quan v nn d liu multimedia, k thut watermarking, cc phng php nh gi cht lng v cc phng php m phng phc v cho qu trnh nghin cu v thc hin cc k thut ny. 2.1. Tng quan v nn d liu Multimedia 2.1.1. Tng quan v multimediaChng ta ang chng kin mt cuc cch mng trong cc cng ngh truyn thng v my tnh trong th k 21. Ngnh cng nghip vin thng tri qua mt sthayitolntmngtngtsangmngschophpcngngh Internet pht trin nh v bo nh ngy nay. Truyn dn t tng t sang truyn dn s mang li cho chng ta rt nhiu c hi trong tng kha cnh ca cuc sng. Vin thng, Internet, gii tr s, v tnh ton tng qut ang tr thnh mt phn tt yu ca cuc sng hng ngy. Ngy nay chng ta ang ni nhiu v cc mng s, s biu din s ca cc nh, cc b phim, video, tivi, thoi, th vin stt c bi v s biu din s ca tn hiu mnh hn rt nhiu so vi s biu din tng t v x l, tnh ton, lu tr, khi phc, v truyn dn qua khong 5cch a l di. Trong nhng nm gn y c nhiu cc thnh tu nhiu ngha trong x l nh tnh, video, ha, thoi, v cc tn hiu audio thng qua cc my tnh s t c cc thch thc ng dng khc nhau. Nh mt kt qu tt yu, thng tin multimedia m bao gm nh, video, audio, thoi, vn bn, v cc loi d liu khc c tim nng tr thnh ch l mt kiu d liu. Vin thng khng ch cn l nn tng truyn thng thoi im ti im gia hai u cui. Nhu cu cho truyn thng cc d liu multimedia thng qua cc mng thng tin vin thng v truy nhp d liu multimedia thng qua Internet ang pht trin mnh m. lm c iu th cn thit rng s biu din d liu v m ha d liu multimedia phi c tiu chun ha trn cc ng dng v cc nn tng khc nhau.D liu video v nh tnh l mt phn rt quan trng ca d liu multimedia v chng chimmt phn ln bng thng trong truyn thng multimedia. Do vy, s pht trin cc k thut nn nh hiu qu ang tip tc tr thnh mt thch thc quan trng cho chng ta, c trong hc thut v trong cng nghip.Mc d s biu din s ca cc tn hiu mang li nhiu u im so vi biu dintngt, nhngchngcnmt slngrt lnccbit cholutrv truyn dn. V d, mt tn hiu audio cht lng cao yu cu xp x 1,5Mbps cho biu din s v lu tr [1]. Mt tn hiu truyn hnh mu phn gii thp, tc 30 khung hnh trn giy vi mi khung bao gm 640x480 pixels (24 bits trn mt pixelmu) th yu cu ln hn 210Mbps cho lu tr.V khi mt b phim mu c thi gian 1 ting m c s ha th yu cu khng gian lu tr xp x 95 Gbytes. S truyn dn cc tn hiu s ny thng qua cc knh thng tin c bng thng hu hn l v cng kh khn v thm tr l khng th trong nh dng d liu gc ny. Mt iu rt quan trng l hu ht cc tn hiu multimedia 6nh nh, video, v thoi thng bao gm mt s lng ln cc thng tin d tha khng cn thit trong s biu din cng nh i vi h thng cm nhn ca con ngi. Do chng ta c th thc hin nn cc d liu ny gim cc d tha trong biu din d liu p ng cc yu cu truyn thng v lu tr.2.1.2. Hiu qu nn d liu multimediaGing nh bt k mt h thng no khc, cc thc o v hiu qu ca mt thuttonnnlccnguyntcquantrngchoslachnthut ton. Cc phng php xc nh hiu qu ca cc thut ton nn d liu c th c xem xt t nhiu kha cnh khc nhau ph thuc vo cc yu cu ng dng: t l nn t c, cht lng ca d liu sau khi khi phc, s phc tp tng i ca thut ton, tc thc hin2.1.2.1. T l nn v s bit trn mt muThc o ph bin nht xem xt hiu qu ca mt thut ton nn d liu l t l nn. N c nh ngha l t l ca s lng cc bit dng biu din d liu gc trn s bit dng biu din d liu nn. Xem xt mt nh c kch thc 256x256 yu cu 65536 bytes lu tr nu mi pixel c biu din bi mt byte n. Nu phin bn nn ca nh c th c lu tr trong 4096 bytes, th khi t l nn t c bi thut ton nn l 16:1. S bin th ca t l nn l s bits trn mt mu. Thc o ny cho bit s lng cc bit trung bnh biu din mt mu n ca d liu (v d: s lng bits trn mt pixel ca nh m ha). Nu 65536 pixels ca mt nh c nn ti 4096 bytes, th chng ta c th ni rng thut ton nn t c trung bnh 0,5 bit trn pixel. Do vy, s lng bits trn mu c th c o bi t l ca s lng cc bt ca mt mu cha nn n trn t l nn [1].72.1.2.2. Cc thc o cht lngThconyth khngngdngchoccthut tonnnkhngtnhao. Thc o cht lng hay trung thc l c bit quan trng cho cc thut ton nn c tn hao cho video, audio, nh, thoi, bi v d liu sau khi khi phc th khc vi d liu gc v h thng cm th ca con ngi l phin ta phn x sau cng cht lng ca d liu sau khi khi phc. S khc nhau ca d liu sau khi khi phc so vi d liu gc gi l s mo dng. Nh vy thut ton nn cho cht lng cao hn ch khi mo dng l nh hn. Cc phng php o cht lng c th l rt ch quan da vo cm nhn ca con ngi hay c th c xc nh khch quan da s dng s nh gi thng k v ton hc. Thc t c nhiu thc o nh gi cht lng ch quan v khch quan khc nhau nh gi cht lng ca cc thut ton nn.- Thcochtlngchquan:Thngthngthcocht lngch quancnhnghanhimsngi quanst trungbnhMOS(mean observer score). Thnh thong, n cng cn c gi l im s quan im trung bnh(meanopinionscore). CnhiucchthngkkhcnhautnhMOS. Trong mt trong s cc cch n gin nht, mt s nhng ngi quan st c ngha thng k c chn ngu nhin nh gi cht lng bng nhn thy ca cc nh c khi phc li. Tt c cc nh c nn v gii nn bi cng thut ton. Mi ngi quan st cho mt im s cho mi nh sau khi khi phc da trn s cm nhn v cht lng ca nh ca anh (ch) ta. Trung bnh ca cc im c gn bi tt c nhng ngi quan st cc nh c khi phc c gi l im quan st trung bnh MOS. Cc k thut xc nh MOS c th khc nhau cho cc loi d liu thu nhn khc nhau. Phng php xc nh cht 8lng ch quan ca mt nh tnh c th hon ton khc cho video hay d liu thoi. - Thc o cht lng khch quan: Vi phng php khch quan th thc o cht lng khch quan c s dng rng ri nht l li bnh phong trung bnh cnbchai RMSE(Root-mean-squarederror), tstnhiutrnnhiuSNR (signal to noise ratio), t s tn hiu trn nhiu nh PSNR (peak signal to noise ratio). Nu I l mt nh s MxN, I l nh c khi phc li tng ng sau nn v gii nn, khi RMSE c tnh bi cng thc sau:(2.1)Trong i,j ch v tr ca pixel trong nh.SNR theo n v decibel c tnh theo biu thc sau:(2.2)Trong trng hp mt nh 8 bit, th PSNR tng ng c tnh theo dB l:(2.3)Trong 255 l gi tr pixel c th ln nht trong 8 bit.Lu rng mt RMSE thp hn (tng ng SNR hay PSNR cao hn) khng phi lun lun cn thit cho cht lng ch quan cao. Cc thc o li khch 9 MiNjj i I j i IMNRMSE121)] , ( ' ) , ( [1

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MiMjMiNjMiNjj i I j i Ij i IRMSEj i IMNSNR1 121 12101 122)] , ( ' ) , ( [) , (log 10) , (1log 20

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RMSEPSNR255log 2010quan ny khng phi lun lun tng quan tt vi cc thc o cht lng ch quan. C nhiu trng hp, trong PSNR ca mt nh c khi phc c th l tng i cao, nhng cht lng ch quan li tng i ti khi c nhn nhn bi mt ngi. V vy s la chn thc o ch quan hay khch quan nh gi thut ton nn v gii nn thng ph thuc vo cc tiu chun ng dng. 2.1.2.3. Tr m haTr m ha l mt phng php nh gi hiu qu khc ca cc thut ton nn trongcch thngm havgiimtngtc(vd: truyn hnhhi tho tng tc, thng tin thoi thi gian thc).Thut ton nn phc tp c l s em li t l nn tt hn, nhng n c th dn ti tng tr m ha, nh hng cc ng dng tng tc thi gian thc. 2.1.2.4. phc tp m ha. phc tp m ha ca mt thut ton nn thng c xem xt l mt php o hiu qu trong yu cu tnh ton thc hin m ha v gii m l mt nguyntc quan trng. Cc yucutnhtonthngcxcnhbngs lng cc php tnh s hc v cc yu cu b nh. Thng thng s lng cc php tnh s hc c miu t bi MOPS (million of operations per second). Nhngtrongkthut nn, MIPS(millionofinstructionspersecond) thng c s dng xc nh hiu qu nn trong mt kin trc thut ton c th, c bit khi thc hin cc s thut ton nn bng cc kin trc b x l tn hiu s DSP.2.1.3. Tng quan v nn nh10M hnh tng quan ca nn nh tnh c th c m t s dng mt s khi th hin trn Hnh 1.1.Hnh 2.1: Mt m hnh nn nh tng qutPhn tch thng k ca mt nh thng thng cho thy rng c mt tng quan rt ln gia cc pixel lin k nhau. iu ny gy ra s d tha thng tin trong nh. S d tha ny phn ln c th loi b bng vic gii tng quan nh vi mt vi k thut tin x l. Tng qut, cc k thut nn nh tnh ph thuc vo hai nguyn l gim d tha c bn l gim d tha v mt khng gian v gim d tha v mt thng k. D tha khng gian l s ging nhau ca cc pixel lin k trong mt nh v n c lm gim bng cch cc k thut gii tng quan nh l m ha d on, m ha chuyn i, m ha bng con,Cn ccdthavmt thngkth clmgimbngphngphpmha entropy, nh l m ha Huffman, m ha s hcKhi gii tng quan hay tin x l trong Hnh 2.1 l bc thc hin gim d tha khng gian ca cc pixel nh. Trong ch m ha khng tn hao th nh c gii tng quan c x l trc tip bi b m ha entropy. Trong ch m ha tn hao, nh c gii tng quan l i tng cho x l cao hn che hay loi i thng tin khng lin quan m ph thuc vo tnh t nhin ca 11nh nnGii tng quan hay tin x lM haEntropyKhi x lnh u vo M ha khng tn haoM ha tn haong dng ca nh v cc yu cu cht lng ca nh khi phc. Qa trnh ny c gi l qu trnh lng t ha. Cc pixel nh c gii tng quan v gii lng t ha sau c a ti qu trnh m ha entropy to ra d liu nh nn.2.1.4. Cc chun nn d liu multimedia2.1.4.1. Chun m ha nh tnh.Hai t chc chnh trong lnh vc nn nh tnh l ISO v ITU-T. ISO thc hin x l thng tin lin quan n cc vn nh l lu tr nh v phc hi nh, trong khi ITU-T gii quyt cc vn lin quan n truyn dn thng tin. JPEG (Joint Photographic Expert Group) l tiu chun c pht trin bi s kt hp gia ISO v ITU-T vo nm 1992 cho cc nh tnh cho c nh en trng v nh mu. C mt s hiu nhm trong rt nhiu ngi rng JPEG l mt thut ton n cho nn nh tnh. Thc t, chun JPEG nh ngha ra 4 ch hot ng [1][3], chng l: Ch da vo DCT tun t, ch khng tn hao tun t, ch da vo DCT lin tc, v ch th bc. Thut ton c s dng rng ri cho nn nh trong ch da vo DCT tun t c gi l Baseline JPEG. H thng JPEG hin ti c thc hin vi mc ch nn cc nh tnh vi tc bit l t 0,25 n 2 bits trn mt pixel. JPEG2000 l chun m ha nh tnh th h tip theo nhm t c cc tc bit thp hn trong khi cht lng cao hn vi nhiu cc c tnh mong mun thm vo p ng cc thch thc mi m JPEG khng c. Cc chun nn nh hai mc ph bin l Group 3 v Group 4 (cng c gi l ITU-T rec T4 v T6) c pht trin bi ITU-T trong nm 1980 cho nn fax, v JBIG c pht trin bi ISO trong nm 1994 cho nn nh en trng.122.1.4.2. Cc chun m ha videoMPEG (Moving picture expert group) l chun ca ISO cho mt h thng nn s x l cc nh ng (video) kt hp vi audio. MPEG-1 (c bit nh ISO 11172) l th h u tin ca cc tiu chun nn s cho video v audio stereo hai knht ctcbit khong1,5Mbps cholutrtrongCD-ROMS. MPEG-1 c chun ha vo nm 1994.ISO pht trin mt chun tip theo l MPEG-2 (c bit nh ISO 13818) vo nm 1995 p ng cc yu cu ca cc h thng nn s cho video v audio qung b cht lng cao ti tc 6-10Mbps. MPEG-4 c chun ha vo nm 1998, nhm p ng cc thch thc mi ca m ha video theo i tng cho cc ng dng multimedia. y ban MPEGcng ang pht trin ci c gi l giao din m t ni dung multimedia, hay MPEG-7. C mt s hiu nhm rt ph bin rng MPEG-7 l mt chun nn video mi khc. S tht l MPEG-7 khng nh ngha bt k mt thut ton nn mi no. N thc hin gii quyt cc vn nh nh dng file v m t siu d liu ca video nn nh ngha ra mt tiu chun cho s m t nhiu loi thng tin multimedia khc nhau m c m ha bi cc b m ha tiu chun.Mt chun khc cng ang c pht trin bi y ban MPEG l MPEG-21.MPEG-21 vi mc ch l cho php s s dng tng ln v trong sut cc ngun ti nguyn Multimedia dc theo mt phm vi rng ca cc mng v cc thit b. Song song vi ISO, ITU nh ngha ra cc chun nn chui nh cho cc ng dngtruyndnnhlhi thotruynhnh, inthoi hnhH261lmt chun m ITU pht trin vo nm 1990 cho phn m ha video ca chun hi tho truyn hnh (H.320) truyn video ti tc bit 56Kbps 2 Mbps thng qua knh vin thng.H.263 l chun m ha video tc bit thp, c pht 13trin vo nm 1995 cho m ha video truyn dn video ti tc bit thp hn 28,8Kbpsthngquaknhvinthng. H264lchunmhavideotintin, c pht trin vo nm 2003, v hin nay ang c ng dng rt rng ri. 2.1.4.3. Chun m ha audioN lc chun ha cho audio s c bt u trong lp audio ca chun m havideoMPEG. LungbitMPEGbaogmcctnhiuaudiovvideov chngctnghpti bgii m. CcchunmhaaudioMPEG-1v MPEG-2 l cc chun quc t u tin trong lnh vc nn audio s cht lng cao. H thng m ha audio MPEG-1 hot ng trong cc ch tn s n hay ch stereo hai knh ti cc tn s ly mu 32KHz, 44.1KHz, 48Khz. H thng cnhrtrong3lp:LpI, IIvIIIchocctcdliukhcnhau. MPEG-1 lp I cho cht lng cao ti tc d liu 192Kbps/knh, trong khi lp II cung cp audio cht lng cao ti tc d liu 128Kbps, v lp III cung cp tc d liu 64Kbps. H thng m ha audio tin tin MPEG-2 (MPEG-2 AAC) hot ng ti cc tn s ly mu gia 8 v 96KHz v h tr ln ti 48 knh audio. MPEG-2 AAC c s dng nh phn li ca chun m ha audio MPEG-4 ti cc tc d liu bng hay ln hn 16Kbps/knh. M ha MPEG-4 cho cc i tng audio cung cp cc cng c nn khc nhau cho cc m thanh t nhin cng nh cc m thanh tng hp cho mt phm vi tc bit rng. Cc chun m ha audio khc nh AC-3 Dolby, Philips DCCMP3 l mt chun rt ph bin trn internet cho audio v music. Tuy nhin, MP3 khng phi l mt chun m ha audio mi, n l chun MPEG-1 audio lp III.2.2. WatermarkingK thut Watermarking thc hin nhng dliu mrng, c gi l Watermark, vo trong mt bn tin. Ti pha thu, d liu nhng ny c th c 14nhn bit v tch ly bng mt phng php thch hp tng ng. Vic phn loi Watermarking c th c xem xt theo nhiu kha cnh, c th l: nu theo cm nhn ca con ngi th n c chia ra loi n v hin. Nu theo mnh ca n th c th chia ra loi mnh v loi yu. Theo cc ng dng th n c th l loi c s ngun hay ch.Theo loi ti liu th n c th l text,nh,m thanh, video. Theo min lm vic th n c th l loi min khng gian hay min tn s. C watermarking n hay hin u c th c s dng cho bo v bn quyn tc gi; thm vo loi n cng hu ch trong cc ng dng bo mt nh chuyn i du v truyn thng tin mt. Loi watermarking mnh c th lm v tc dng cc tn cng nhm loi b watermark.Mt watermark c th c nhng vo trong text, hnh nh, m thanh hay video nh d liu tha. Ph thuc vo cc thut ton nhng m cc watermark c th c gii tch chnh xc nh ban u hay khng. Do c tnh mnhca thut ton watermarking trong min DCT, ti la chn watermarking trong min DCT nghin cu v pht trin cho ng dng nhn thc hnh nh cho camera bo mt gim st v cho ng dng bo v bn quyn tc gi.2.3. Thc hin m phng v pht trin trn Matlab/Simulink v FPGA2.3.1. Cc cng vic cn thc hinThut ton Watermarking c th thc hin trn nhiu nn tng khc nhau nh phnmm, phncng, iukhinnhng, DSP, FPGAVi ccngdng thng mi yu cu thi gian thc th gii php phn mm s gy ra tr ln, do vy mc ch ca nghin cu ny l tm hiu v nghin cu gii php tch hp thut ton watermarking trn mt IC cho cc ng dng nghin cu. FPGA l gii php hiu qu cho c tc x l nhanh, lp trnh linh hot v gi thnh hp l. 15 ti la chn cc cng c pht trin FPGA ca hng Xilinx ca Hoa K nghin cu pht trin, l ISE v System Generator.u tin cc module nn nh JPEG, module watermarking cho nh s trong min cha nn v module watermarking cho nh s trong min nn nn c xy dng vi cng c thit k kin trc mc cao l MATLAB/SIMULINK kim tra cc thut ton v hiu qu ca n. Bc tip theo thc hin xy dng cc khi thut ton trn cc cng c ISE v System generator s dng ngn ng m t phn cng VHDL. 2.3.2. Gii thiu cc cng c ca Xilinx- ISE (10.1, 11.1):L cng c xy dng v lp trnh FPGA. ISE thc s l mt mi trng tng hp v thc thi ton din cho cc chip kh trnh ca Xilinx. ViISE11.1, ngithitkcthlptrnh,g ri, m phng,dch v np chng trnh mt cch nhanh chng v d dng. Ngi thit k cng c th thit k h thng ca mnh theo nhiu cch khc nhau: vi m vhdl, vi s RTL, hoc vi s trng thi (state machine).- System Generator (10.1, 11.1) (sysgen): l cng c pht trin h thng cho FPGA, cho php thit k h thng dng cc khi, v h tr m phng, debug, to code np vo FPGA hoc kt hp vo nhng ng dng ln hn.Sysgen c xy dng nh mt Block Set ca Simulink trong Matlab. Do , sysgenthahngtt cccuimcaSimulinktrongvicxydngh thng v m phng. Sysgen cn s dng th vin ca Logic Core xy dng cc block ca mnh. Trong th vin ca Sysgen c cc khi thc hin cc chc nng t c bn nh cng, tr, nhn, cc khi logic,...cho n nhng thit k phc 16tp hn nh cc DSPs, b lc s, nhn chp,..., cc b nh tch hp: Single Port, DualPort Ram, FIFOs, cc thanh ghi...Sysgen cn cho php ngi thit k to ra cc khi thc hin nhng nhim v ring bng khi Black Box, ti y ngi thit k s to ra cc entity v ci m ca n vo Black Box to ra cc thit k ring ca mnh.Nhngthitkca Sysgencthcdchranhiukiudliu,cth thnh file bit np ngay vo phn cng, hoc thnh cc thit k ghp vo mt hthnglnhn.Vi vickt hpvi MathworkxydngSysgen, Xilinx lm cho vic thit k h thng trn nn FPGA ca mnh tr nn thun tin v n gin hn rt nhiu i vi ngi lm k thut. Kt lun:Qua chng ny, lun vn mun gi ti ngi c ci nhn tng quan v multimedia,s pht trin ca nn d liu multimedia v cc k thut watermarking cho multimedia. Mt cng c rt hiu qu s dng m phng v chng minh kt qu ca cc thut ton nn v watermarking cho multimedia l Matlab/Simulink. Vi s pht trin ca cng ngh FPGA, cng vi s h tr ca cc cng c lp trnh,vic thc hin cc thut ton nn v watermarking phc tp trn FPGA l c th.17CHNG 3: C S L THUYT CA CC K THUT NN NH JPEG V WATERMARKING CHO NH SChun nn nh tnh JPEG c kho st v thc hin trong lun vn ny l JPEG Baseline. C s ton hc ca JPEG Baseline l cc k thut chuyn i khng gian mu v tc ly mu mu, bin i cosine ri rc (DCT), lng t ha bin i, qut zigzag v m ha entropy. K thut watermarking cho nh s c kho st v thc hin l k thut watermarking trong min DCT, c trong min nn v min cha nn JPEG.M hnh l thuyt thc hin watermarking cho nh s trong chng ny cng cho php t c watermarking n hay hin thng qua iu chnh cc tham s trong m hnh.3.1. K Thut nn nh s JPEGJPEG c gii thiu trong Chng 2. JPEG nh ngha ra 4 ch hot ng trong c c nn c tn hao v khng tn hao. ti la chn ch nn c tn hao trn c s bin i DCT thc hin nn nh v watermarking. Thut ton c la chn cho nn nh l thut ton nn JPEG Baseline. y l thut ton c s dng rng ri v kh n gin trong ch nn nh JPEG trn c s bin i DCT, nhng cng mang li hiu qu nn cao. Thut ton nh ngha cho vic nn cc nh tnh vi 1 ti 4 thnh phn. S lng cc thnh phn cho nh n sc l 1, trong khi mt nh mu c th c ti 4 thnh phn mu. Baseline Jpeg cho php ch cc mu 8 bit trong mi thnh phn ca nh ngun. Mt v d ca nh mu 4 thnh phn l nh CMYK (Cyan, Magenta, Yellow, v Black),y l nh c s dng trong nhiu cc ng dng nh in n, scan,Mt nh mu thng c 3 thnh phn mu c bn l RGB. Trong mt nh mu 18thng thng, s tng quan v khng gian gia cc thnh phn mu R, G, B l rt ln. t c hiu qu nn tt th s tng quan gia cc thnh phn mu phi c gim u tin bng vic chuyn i nh RGB sang mt khng gian mu gii tng quan. Trong Baseline JPEG, mt nh 3 mu RGB c chuyn i sang mt khng gian mu L-C (chi-mu) nh l YCbCr, YUVTip theo nh c ly mu mu li v sp xp a ti cc thut ton li ca JPEG Baseline. Thut ton JPEG Baseline c th hin theo m hnh khi Hnh 3.1.Nh vy cc thut ton nn v gii nn nh JPEG Baseline gm c: chuyn i khng gian v tc ly mu mu, bin i cosin ri rc (DCT) v bin i ngc (IDCT), lng t ha v gii lng t ha, qut zigzag,m ha entropy v gii m entropy. Cc thut ton ny s c gii thiu c th trong cc phn tip theo.FDCT Lng t ha Qut zigzag M ha Entropy D liu nh nnBng lng t haBng m EntropyD liu nh u voBlock8x8B m ha(a)Qut zigzag ngcBng m EntropyB gii m haIDCTGii m ha EntropyGii lng t haBng lng t haD liu nh nnD liu nh khi phc(b)19Hnh 3.1: Baseline JPEG: (a) nn, (b) gii nn3.1.1. Chuyn i khng gian mu v tc ly mu muS thu nhn hnh nh ca con ngi hay h thng th gic con ngi (HVS) c th ch cm nhn c nh sng c di bc sng trong phm vi nh trong ph trng in t, t 400nm n 700nm, hay thng c gi l cu vng 7 mu: , da cam, vng, lc, lam, trm, tm. Hn th na, 7 mu sc cu vng c th c to thnh t 3 mu gc c bn. Trong ngnh cng ngh video v movie, hai h 3 mu c bn c s dng rng ri l: RGB v YCbCr. Mi mt h ba mu c bn ny c gi l mt khng gian mu.3.1.1.1. Khng gian mu RGBKhng gian mu RGB c 3 mu c bn l: (R-red), lc(G-green), lam(B-blue). y l cc mu m mt ngi c th nhn thy v s kt hp ca chng trong cc sng khc nhau c th to ra tt c cc mu trong th gii thc. Trong nh v video s, mi pixel c ba phn t biu din cho ba mu theo sng.3.1.1.2. Khng gian mu YCbCrYCbCr l mt khng gian mu khc bn cnh RGB. Y biu din cho chi hay sng ca mt pixel; Cb v Cr biu din s khc nhau v mu sc trong mt pixel. RGB v YCbCr c th chuyn i qua li ln nhau. Theo ITU-R:(3.1)V (3.2)20;+ + Y) - (R 0.713 Cr Y) - 0.564(B Cb0.114B 0.587G0.299R Y;+ + Cb Y BCr Cb Y GCr Y R772 . 1714 . 0 344 . 0402 . 1T phng trnh (2.2) c th thy rng Cr v Cb c th c gi tr m, nhng thc t cc pixel nh v video biu din trong 8 bit, phm vi d liu l 0~255 v ch mang gi tr dng. Do vy phng trnh (2.2) c iu chnh nh sau:(3.3)Khng gian mu RGB v YCbCr c th chuyn i ln nhau, tuy nhin chng c s dng trong cc ng dng khc nhau. RGB biu din cho nh cui cng cho cc kt qu hin th, YCbCr l d liu trung gian cho qu trnh x l nh v video.3.1.1.3. Tc ly mu mu V h thng th gic con ngi th nhy cm vi sng hn l vi mu[3]. Khng ging RGB, cc mu c cha trong cng phn gii, Cb v Cr c th trong phn gii thp hn so vi Y, mc d cht lng nh cui cng vn tha mn cm nhn th gic ca con ngi. T cc kt qu thc nghim, cc nh khoa hc rt ra 3 loi tc ly mu mu l 4:4:4, 4:2:2 v 4:2:0. Tc ly mu 4:4:4 c s dng trong cc ng dng qun s, cng nghip, thng mi m i hi phn gii v tc ly mu rt cao. Tc ly mu 4:2:0 gim tc ly mu ca khng gian mu xung mt na so vi tc 4:4:4 bi n b i 75% cc mu mu. Tuy nhin, bi tnh t nhin ca h thng th gic con ngi, mt ngi thng khng th phn bit c s khc bit. Vi cc ng dng v cc thut ton khc nhau, Y, Cr, Cb c th c kt hp ring r t c cc hiu ng khc nhau.21;+ + + + 128 ) ( 713 . 0128 ) ( 564 . 0114 . 0 587 . 0 299 . 0Y R CrY B CbB G R Y3.1.1.4. MacroblockTrong chun JPEG,mt macroblock l mt khi cc mu mu hay chi 16x16, 8x8, v n l phn t d liu c bn cho qu trnh x l. Macroblock l i tng cho cc hot ng m ha nh: bin i cosin ri rc, lng t ha v m ha entropy. ng vi cc thut ton JPEG khc nhau th macroblock c kch thc khc nhau. Thng thng nht l kch thc 16x16, gi l mt pel. Xem xt vi tc ly mu mu 4:2:0, vi 4 mu khi Y, 1 mu khi Cb v 1 mu khi Cr. Nu macroblock l 1 khi 16x16 pixel th n s gm c 4 khi mu Y 8x8, mt khi Cb 8x8 v mt khi Cr 8x8. Y Cb CrHnh 3.2: 4:2:0 macroblock 3.1.2. Bin i Cosin ri rc (DCT) Bin i cosine ri rc l mt cng c ton hc x l cc tn hiu nh nh hay video.N s chuyn i cc tn hiu t min khng gian sang min tn s v bin i ngc li t min tn s quay tr li min khng gian m khng gy tn hao n cht lng. Bin i cosine ri rc l phn thc ca bin i Fourier, v n c th c tnh ton nhanh bng phn mm v phn cng. hiu r hn v bin i cosine ri rc, u tin ti s bt u vi bin i Fourier.3.1.2.1. Bin i Fourier228x8 8x88x8 8x88x8 8x8Trc khi tho lun v bin i cosine ri rc, bin i Fourier s c gii thiungngn, bi v bini cosineri rccthahngtbini Fourier.Theo l thuyt Fourier th bt k mt tn hiu no u c th xy dng bng tnh tng ca mt chui cc hm sine v cosine theo tn s tng dn. N c vit nh sau[2]:( ) ( ) ( ) dx ux i ux x f u F 2 sin 2 cos ) ( ) ( (3.4)Trong f(x) l tn hiu vi bin thi gian x, v F(u) l kt qu bin i vi bin tn s u. Mt c tnh rt quan trng ca bin i Fourier l hm bin i ngccthchuynitnhiutmintnstrli minthi gian, theo phng trnh sau:( ) ( ) ( ) du ux i ux u F x f 2 sin 2 cos ) ( ) ( (3.5)Bn cnh thc hin chuyn i t min khng gian sang min tn s v ngc li, bin i Fourier cng c th lm vic trong min khng gian thc hin bin i t min khng gian sang min tn s v ngc li. x l cc tn hiu ri rcnhccnhsha, mthanh,lcctnhiuri rc, th bini Fourier ri rc v bin i ngc ca n c suy lun ra nh cc biu thc sau [2]:

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102sin2cos ) (1) (NNuxiNuxx fNu F (3.6)

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102sin2cos ) ( ) (NNuxiNuxu F x f (3.7)23Trong F(u) l h s bin i Fourier ri rc, f(x) l d liu gc u vo, v N l thnh phn tn s ri rc cho vic xy dng bin i Fourier ri rc.3.1.2.2. Bin i cosine ri rc (DCT)Nu mt nh c coi nh mt hm ca bin vi khong cch nh l bin, th theo l thuyt Fourier hm c th c xy dng bi mt chui cc hm sine v cosine tng dn theo tn s. Khi hm ch gm c cc thnh phn sine th gi l bin i sine, v nu hm ch gm cc thnh phn cosine th n c gi l bin i cosine. C bin i Fourier, sine v cosine u c cc ng dng ring trong x l nh. Tuy nhin, trong nn nh, video v watermarking th hu ht u s dng bin i cosine. hiu r hn, ta xem xt hai tn hiu: mt tn hiu chn v mt tn hiu l (Hnh 3.3). Hnh 3.3: Dng sng tn hiu chn v lTn hiu chn c bin khc khng ti thi im 0 hay tn s 0 trong khi tn hiu l c bin l 0. xy dng tn hiu chn hay l th c hm sinehaycosineucthclachn, tuynhinvi hmbini 24cosine th kt qu cho tn hiu chn s yu cu phm vi tn s t hn, trong khi vi hm bin i sine th kt qu cho tn hiu l s c phm vi tn s t hn (Hnh 3.4).Hnh 3.4: Xy dng cc tn hiu vi bin i cosine v sineMt nh c th c xem xt nh mt tn hiu chn bi v sng trung bnh ca n hay sng ti tn s 0 lun c bin khc 0 [2][3]. Do vic xy dng v x l nh vi cc hm bin i cosine s yu cu t cc thnh phn tn s hn l so vi bin i sine. Nh vy l do chn bin i cosine cho x l nh s l: u tin, n c th loi b s tng quan gia cc pixel nh trong min khng gian. Th hai l bin i cosine ri rc yu cu t s phc tp tnh ton v ti nguyn hn.Bin i cosine ri rc mt chiu:(3.8) (3.9)25

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+102) 1 2 (cos ) ( ) ( ) (NxNu xx f u u C

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+102) 1 2 (cos ) ( ) ( ) (NuNu xu C u x f y, C(u) l h s bin i cosine ri rc, f(x) l bin tn hiu, N l s cc phn t, u=0,1,2,..,N-1, v (3.10)Thut ton bin i cosine ri rc mt chiu trn s tn rt nhiu ti nguyn tnh ton. Nu tnh ton mt bin i 8 phn t th n cn 56 b cng v 72 b nhn. V vymt sthut tonnhanhsclachnvtrnhbytrong chng sau.Do nh s l cc ma trn hai chiu, do bin i cosine ri rc hai chiu c s dng, phng trnh bin i cosine ri rc 2 chiu nh sau:

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+

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+Nv yNu xy x f v u v u CNyNx2) 1 2 (cos2) 1 2 (cos ) , ( ) ( ) ( ) , (1010 (3.11)Bin i DCT 2 chiu ngc (IDCT)

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+

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+Nv yNu xv u C v u y x fNuNv2) 1 2 (cos2) 1 2 (cos ) , ( ) ( ) ( ) , (1010 (3.12) y C(u,v) l h s bin i cosine ri rc, ) (u , ) (v c nh ngha theo (3.10), f(x,y) l phn t ma trn hai chiu u vo, N l s hng hay s ct u vo.Mt ma trn 8x8 vi 8 bit cho mi h s c xem nh mt khi d liu n v trong x l nh, khi phm vi d liu ca cc h s bin i cosine ri rc c th c lng t phng trnh (3.11). Xem xt trng hp xu nht th gi tr ca mt h s c th l: ( ) ( ) ( ) ( ) 7070max max max max2040864 * 255, ,y xy x f v u v u C (3.13)26'NNu21) ( Vi u=0Vi u0( ) ( ) 2040 , ,max min v u C v u C(3.14)T phng trnh (3.11) v (3.12) chng ta cho th thy rng cu trc ca bin i cosine ri rc hai chiu s rt phc tp cho c thc hin phn cng v phn mm. Tuy nhin, v bin i cosine ri rc l mt php bin i trc giao, nn bin i cosine ri rc hai chiu c th tnh ton n gin bng thc hin bin i cosine ri rc mt chiu theo cc hng ri sau cc kt qu c bin i li theo cc ct[1][2][7][[5] (Hnh 3.5).Hnh 3.5: Bin i DCT 2 chiu 8x8 thng qua bin i DCT mt chiu 1x8Cng phng php ny th bin i cosine ri rc ngc hai chiu c th t c bng thc hin bin i cosine ri rc ngc mt chiu hai ln. S tng quan v mt khng gian trong mt nh khng th loi b trong min khng gian v mi pixeltrong nh tng quan vi cc pixel khc,v s cm nhn hnh nh ca con ngi c th d dng pht hin ra v tr thay th trong min khng gian. loi b s tng quan gia cc pixel, bin i cosine ri rccththayiccbinv tr ctngquancht chvi nhautimin khng gian thnh cc tn s ri rc khc nhau ti min tn s. ngha cami h s ca bin i cosine ri rc l: h s th nht ca DCT gi l h s DC, n biu din cho gi tr trung bnh ca ma trn pixel, trong khi 27 tt c cc h s cn li l phn AC. Cho v d mt ma trn 8x8 phn t nh, h s DC l: 7070) , (81) 0 , 0 (y xy x f C(3.15)C(0,0) l trung bnh ca tt c cc gi tr pixel ca ma trn 8x8 trong min khng gian. H s DC ny cho bit sng trung bnh ca ma trn nh. Bng 3.1 cho bit v tr ca cc h s DC v AC trong ma trn cc h s bin i cosine ri rc 8x8.Xem xt mt v d bin i cosine ri rc cho ma trn im nh 8x8 nh th hin trn Hnh 3.6. Vi cm nhn th gic ca con ngi th cc thnh phn tn s cao trong min tn s khng qu nhy cm nh cc thnh phn tn s thp. c tnh ny l rt hu ch cho nn nh v watermarking.28Bng 3.1: Cc h s DC v ACa- ma trn 8x8 pixelb- ma trn h s DCT 8x8 t a3.1.3. Lng t ha cc h s DCTSau khi bin i cosine ri rc,s tng quan gia cc pixel ca mt nh trong min khng gian c gii tng quan thnh cc tn s ri rc khc nhau trong min tn s. Do s cm nhn th gic ca con ngi l rt nhy vi h s DC v cc tn s thp, mt phng php lng t ha v hng c thit k cn thn c th gim s d tha d liu m vn gi c tnh trung thc ca nh. Bc ny s gy ra mt thng tin v do vy to ra mo dng ti nh khi phc. l nguyn nhn ti sao Baseline Jpeg l nn c tn hao. Mi h s ca 64 h s DCT c lng t ha ging nh nhau. 64 tham s kch thc bc lng t cho php lng t ha 64 h s DCT c ly t mt ma trn lng t ha 29c- cc thanh bin trong min khng gian d- cc thanh h s trong min tn sHnh 3.6: so snh cc ma trn trc v sau DCT8x8. Mi phn t trong ma trn lng t l mt s nguyn c gi tr t 1 ti 255. Mi h s DCT C(u,v) c chia bi tham s kch thc bc lng t tng ng Q(u,v) trong ma trn lng t v c lm trn ti s nguyn gn nht nh phng trnh sau:( )

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) , () , (,v u Qv u CRound v u Fq(3.16)Qa trnh gii lng t c thc hin theo phng trnh sau:) , ( * ) , ( ) , ('v u Q v u F v u Cq (3.17)Chun JPEG khng nh ngha ra bt k mt ma trn lng t c nh no m ngi s dng c quyn la chn mt ma trn lng t [1]. Annex K ca chun JPEG cung cp hai ma trn lng t tham kho, nhng khng phi l yu cu bt buc. Hai bng lng t ny c th hin trong Bng 3.2 v Bng 3.3 [1].Bng 3.2: Ma trn lng t cho thnh phn chiBng 3.2 l ma trn lng t cho thnh phn chi dng thc hin lng t ha cc h s sau bin i DCT ca thnh phn chi ca nh. Bng 3.3 l ma trn lng t mu dng thc hin lng t ha cc h s sau bin i DCT 3016 11 10 16 24 40 51 6112 12 14 19 26 58 60 5514 13 16 24 40 57 69 5614 17 22 29 51 87 80 6218 22 37 56 68 109 103 7724 35 55 64 81 104 113 9249 64 78 87 102 121 120 10171 92 95 98 112 100 103 99ca cc thnh phn mu ca nh. Hai bng lng t ny c thit k da trn cc kinh nghim thc t v cm nhn tm l hnh nh bi Lohscheller [1].Bng 3.3: Ma trn lng t cho thnh phn mu3.1.4. Qut zigzag cc h s DCTSau khi bin i DCT ta thu c cc khi 8x8 biu din cho cc h s tn s. Trong khi ny th cc h s tn s thp s tm li gc cao pha tri ca ma trn DCT. Qut zigzag s sp xp li th t ca ma trn cc h s c sp xp theo tn s theo th t tng dn (Hnh 3.7).3117 18 24 47 99 99 99 9918 21 26 66 99 99 99 9924 26 56 99 99 99 99 9947 66 99 99 99 99 99 9999 99 99 99 99 99 99 9999 99 99 99 99 99 99 9999 99 99 99 99 99 99 9999 99 99 99 99 99 99 99a. ng qut zigzagb. ma trn sau khi qut zigzagHnh 3.7: Qut zigzag ma trn h s DCT d dng cho lp trnh, cc h s bin i cosine ri rc phi c xp xp li theo mt th t tuyn tnh vi s tng dn ca cc tn s. Qa trnh xp xp ny gi l qut zigzag v ng i la chn cc h s trong ma trn theo ng zigzag (Hnh 3.7 a). Quan st Hnh 3.7c v d chng ta thy rng sau khi qut zigzag cc h s c xp xp gn ng theo cc bin ca chng. Mc ch ca qut zigzag l tp hp cc gi tr 0 v cc gi tr nh khc gim tc bit. 3.1.5. M ha EntropySau bin i DCT v lng t ha l cc thut ton min m. Cc thut ton ny thng c gi l m ha Entropy, bao gm m ha Huffman, m ha s hc, y l phng php m ha khng tn hao. tng c bn ca m ha Entropy l cc biu tng thng xuyn xut hin s c m ha bng cc bt 32c. thanh h s trc qut zigzag d. thanh h s sau qut zigzagngn, trong khi cc biu tng t xut hin hn s c m ha bng cc bt di hn. Phng php ny cn gi l m ha c di t m thay i (VLC). iu ny s lm cho tc bit ca lung gim ng k. Hiu qu ca m ha Entropy ph thuc vo s tnh ton chnh xc xc sut xut hin ca mi h s. Tuy nhin, vic tnh ton cc xc sut ca cc h s l gn nh khng th trong cc b m ha v gii m MPEG thi gian thc. Mt gii php l s dng bng m Huffman tnh ton trc cho cc nh cng loi. M ha entropy c th ng dng cho cc h s DC ca cc khi khc nhau, cc h s AC trong cng mt khi, v cc vc t chuyn ng trong cng mt khung. 3.1.5.1. M ha c di bin iKhngging nhm hac dic nhnhASSCI,BCD,, m ha entropy l mt loi m ha c di bin i, c ngha l cc bit m cho cc t m khc nhau l khc nhau. Sau th tc lng t ha v ct xn cc thnh phn tn s cao hn, hu ht cc gi tr h s ca ma trn DCT s l 0. Vi mt thut ton m ha c di t m bin i thch hp th hu ht cc h s 0 c nn li. M ha di t m bin i trong JPEG cng cn c gi l m bc chy (run level code). run cp ti c bao nhiu gi tr 0 t trc mt s khc 0, level biu din gi tr hay mc ca s. Cho v d: mt chui cc h s l: 7, 0, 5, 0, 0, 0, 4, 3, 0, -3,, chng c th c vit li thnh cc m mc chynh: (0,7), (1,5), (3,4), (0,3), (1,-3),Cp(R-L)gingnh(1,5)cth c dch nh mt s 0 ng trc s 5. Do m mc chy s nn rt hiu qu di bit cho mt chui vi nhiu mc 0 lin tc. V vy n s mang li nhiu li ch cho m ha cc h s DCT.3.1.5.2. M ha Huffman33 t c hiu qu m ha cao hn trong min m sau m ha bc chy, m ha entropy nh m ha Huffman l s la chn cn thit. Theo l thuyt Shannon th di t m nh nht ca mt symbol l:

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ssPL1log2(3.18)Trong Lsl di ti u ca mt symbol,Psl xc sut xut hin ca symbol trong mt lung bn tin, v entropy l s lng bit trung bnh cho mt symbol tng th c tnh theo biu thc:

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sssPP Entropy1log2(3.19)Tccphngtrnhtrn, ccdi tmnh phnti uchoxcsut symbol ca m 2 l d dng t c. Nhng trong nhiu trng hp, xc sut xut hin c th khng lun lun l m ca 2, v d l 1/23, khi di t m c to ra bi vic chp nhn xc sut gn ng s khng l ti u. tng ca Huffman l s dng mt cy Huffman tm mt tin t m duy nht. V d:Bng 3.4: V d m Huffman34Symbol Xc sut xut hin M S btA 0,8 1 1B 0,02 0000 4C 0,03 0001 4D 0,07 001 3E 0,08 01 2V cy Huffman tm kim m ca cc symbol trong Bng 3.4 l :Hnh 3.8 : Cy m Huffman cho m ha HuffmanCc cnh ca cy c xp xp bi cc xc sut xut hin chng. Xc sut ca nt l tng ca hai cnh, v hai cnh s l m 1 hoc m 0. Nu mt nhnh l l th n c gn l 1, ngc li n c gn l 0. Nu c hai u l l th ci no c xc sut cao hn s c gn l 1 v ci thp hn c gn l 0. Bngvictmkimcytgcti ngn, mhaHuffmanctht c. Tngtvi cngcymHuffman, ccmHuffmancgii mti cc symbols tng ng. Tuy nhin, v mc ch nn, truyn tt c cc xc sut ca cc symbol i l khng thc t. Thc t mt bng m c tnh ton t trc cho d liu nh c ng dng cho c b m ha v b gii m. Bn cnh vic khng s dng cc bt m rng cho bng cc xc sut s trnh c vic tm kim cy m Huffman, nn ci thin c tc x l. 3.2. Watermarking35 tng chung ca Watermarking l nhng mt vi d liu m rng vo trong mt bn tin ch.Thng tin nhng gi l watermark v d liu ch gi l vt mang (carrier).Cc ngdng caWatermarkingc th lbo vbnquyn, nhn thc, n d liu, cc thng tin mt3.2.1. Watermarking ti min khng gianCc thut ton watermarking th h u tin lm vic trong min khng gian bi v n t yu cu phc tp v chi ph thp trong x l my tnh. Mt phng php trong l m ha LSB: bit LSB ca byte d liu s c sa i nhng cc watermark. M ha LSB rt d b b v v n ch thc hin che phn LSB ca cc byte d liu, v vy n nhanh chng c thay th bng cc k thut khc.Cc k thut tri ph c th tri watermark trong mt ph rng hn chng li tn cng m n lm vic trong mt rng bng tn nht nh. Vic thc hin thut ton watermarking min khng gian cho gi thnh phn cng r hn. Tuy nhin, cc k thut min khng gian khng th t c cc yu cu v mnh ca watermarking.3.2.2. Watermarking ti min DCTChng ta thy rng sau khi chuyn i min lm vic t min khng gian sang min DCT,s tng quan ca cc pixelkhng gian s c gii tng quan thnh cc phn tn s ri rc. H s DC v tn s thp ca ma trn DCT s quyt nh cc c tnh t nhin nht ca mt nh. Sau khi ct xn cc h s tn s cao, tnh trung thc ca nh vn cn tt cho s cm cm th gic con ngi thng qua bin i ngc IDCT. V vy mt phng php t nhin l nhng mt ma trn cc h s DCT watermark vo mt ma trn cc h s DCT nh trong vng tn s trung bnh hay thp hn t c watermark mnh. Hnh 3.9 th hin cc v tr c th nhng watermark.36Tnh cht mnh ca watermarking DCT l nu mt k tn cng c gng loi b watermarking ti cc tn s trung bnh th s ph mt i tnh trung thc ca nh, v mt vi chi tit thu nhn l ti cc tn s trung bnh[1][5][6][20].Phng trnh nhng Watermark[1][4][5][6][7]:(3.20)Trong , Cw(i,j) l h s DCT (i,j) sau khi nhng watermarking;v l cc ch s mnh watermark, cc ch s ny c th xc nh liu watermark l huhnhhayvhnh[1][4][5][6][7]; C(i,j) lhsDCTbanutrckhi watermarking; W(i,j) l h s DCT watermark. Mc d cc thut ton trn thng c ng dng cho cc nh tnh, chng ta c th xem xt mt chui khung video nh mt chui cc nh tnh. Mt phng php hp l l x l mi khung ca video nh mt nh tnh vi cc phng php trn trong min khng gian v min tn s nhng watermark. 3.2.3. Watermarking hin v watermarking n37Cc tn s thpCc tn s trung bnh cho watermarkingCc tn s caoHnh 3.9: Nhng mt watermark tn s gia) , ( ) , ( j i W j i C Cw + Watermarkingnti minDCTcngcththchinbngphngtrnh watermarking(3.20). Ch bngiuchnhcchswatermarkingv, watermark c th tr ln n hay hin. Watermarking hu hnh trong video c ng dng rt ph bin trong video qung b. thc hin k thut ny, mt ma trn cc h s 16x16 DCT s c cng trc tip vi ma trn cc h s 16x16 DCT nh[1][4][5][6][7] nh phng trnh (3.20), v c th hin Hnh 3.10.Ldolachnkhi 16x16thayv khi 8x8ldothchinnhng watermarking ti cc khung Y, m n v c bn ca khung Y l pel v 1 pel c kch thc 16x16. Khng ging nh nhng watermark tn s trung bnh, trong k thut watermarking ny th h s DC v tt c h s AC ca ma trn cc h s DCT nh s b sa i bi vic nhng watermark, v k thut watermarking ny cho kt qu l cm nhn hu hnh cc watermark i vi h thng th gic con ngi. C hai la chn nhng watermark vo cc khung ca mt on video l thc hin watermarking trc hay sau khi nn (Hnh 3.11).38Hnh 3.10: Nhng watermark ti ma trn cc h s 16x16watermarkingNn nh (JPEG)Dng bit JPEGa. Watermarking trong min cha nn (trc khi nn)nh u voNn nh (JPEG)WatermarkingLung bit JPEGb. watermarking trong min nn (trong khi nn)Hnh 3.11: Watermarking trong min cha nn v min nnnh u vo3.2.4. Mt s ng dng ca watermarking nh sTrong phn ny lun vn gii thiu mt s cc m t c th ca cc ng dng c th ca watermarking nh s. Cc m t ny c lun vn nghin cu trn c s cc lo lng v gp ca ngi s hu ni dung v nhng ngi c lin quan n cc lnh vc cung cp ni dung s. (1) Watermarkingchongdngnhnthcvbomt chocchthng camera an ninh gim st.Watermarking c th cung cp s nhn thc v pht hin ph ri cho cc h thng gim st s. Mt vi h thng hin ti cung cp cc la chn watermarking cho cc hnh nh lu tr. Cc h thng ny cho rng ng truyn dn t video camera ti trung tm lu tr l an ton v chng ch thc hin tp trung bo mt cho video khi trung tm lu tr. S tha nhn ny l khng ng nu h thng b tn cng tng truyn dn. Trong trng hp ny, nhn thc phi c thc hin ngay ti video camera cung cp mt h thng bo mt an ton hn. 39iu ny c th t c bng vic s dng mt thit b trn c s phn cng hay mm nhng mt watermark vo tn hiu video ti ngay video camera.(2) Watermarking hin cho ng dng bo v bn quyn tc gi:Trong trng hp ng dng ny, cc nh c hin hu thng qua Internet, v ngi shuni dunglolngrngccnhscsdngvomcch thng mi (v d nh in n thng mi, s dng lm qung co ring) m khng tr tin bn quyn tc gi. y, ngi s hu ni dung mong mun mt du quyn s hu hin r vi nh, nhng khng ngn cm nh c s dng cho cc mc ch khc (v d: nghin cu khoa hc,). S hin ca du s lm r rng bt k s s dng cc nh vi mc ch thng mi no, v do vy s d dng i quyn tc gi (thu nhp t quyn s hu).(3) Watermarking hin c s dng ch cho bit quyn s hu cc nguyn bn gc:Trong trng hp ny, cc nh c hin hu thng qua Internet, v ngi s hu ni dung mong mun ch ra quyn s hu ca cc ti liu c bn (v d: th vin s hu cc tc phm bn tho,), v vy mt ngi quan st c l c khuyn khch gip c nhn, t chc ni danh m s hu cc ti liu ny. y ngi s hu ni dung mong mun mt du nhn hin lm r ngun gc ca cc ti liu. Tn tht thu nhp l vn c quan tm t hn so vi trng hp ng dng (2).(4) Watermarking n cho mt camera tin cy:Trong ng dng ny, cc nh c thu nhn vi mt camera s cho cc ng dng sau trong cc tiu tin tc. y, n l s mong mun ca mt hng tin tc chng minh rng mt nh l ng vi s thu nhn ban u, v khng b 40chnh sa lmgi cnh tng trong nh. Trong trng hp ny, mt watermark n c nhng ti thi im thu nhn. S hin din ca n ti thi im xut bn c mong mun ch ra rng nh khng b sa t khi n c thu nhn. (5) Watermarking n kim tra s chnh sa ca cc nh c lu tr trong mt th vin s:Trong trng hp ny, cc nh (v d: vn tay ca con ngi) c qut v c lu tr vo mt th vin s, ngi s hu ni dung mong mun kh nng pht hin bt k mt s chnh sa no ca cc nh m khng cn so snh cc nh ny vi cc ti liu c qut. y, c s hp l c bn l ngi s hu ni dung s trch ra mt watermark n t nh m n s cho bit rng liu nh liu nh b sa hay b thay th k t khi n c a vo th vin s. y l mt mong mun thit tha v c bit quan trng khi m th vin s c kt ni m rng ti mt mng ngoi, nh l Internet.(6) Watermarking n pht hin cc nh khng thch hp:Trong trng hp ng dng ny, ngi bn cc nh s (v d cc nh ngh thut, ) lo ngi rng cc nh to ra thu nhp cho anh ta c l ang c mua bn trao i bi mt c nhn m s lm chng min ph cho ngi khc, iu ny c th lm mt i thu nhp c ng k ca ngi s hu. Trong trng hpnymongmunrngcthtmkimccnhtrnccwebsitetm watermark ca ngi bn v xc nh cc nh ca ngi bn c ang c hin hu khng.(7) Watermarking n nh bng chng xc thc cho quyn s hu:41Trong trng hp ng dng ny,ngi bn cc nh s nghing rng mt trong s cc nh ca anh ta b chnh sa v xut bn m khng tr tin cho quyns hu. y, spht hin watermarkcangibntrong nhc mong mun phc v nh bng chng rng nh xut bn l s hu ca ngi bn. (8) Watermarking n xc nh mt i tng khng hp l.Trong trng hp ng dng ny,ngi bn cc nh s nghing rng mt trong s cc nh ca anh ta b chnh sa v xut bn m khng tr bt k mt khon no cho s hu tr tu. y, ngi bn thm vo mt watermark n vo cc nh ca anh ta, ti thi im phn phi, ch ra rng ai l ngi m chng c bn ti. Watermark c trch ra c mong mun cho bit nhn dng ca ngi mua cc nh m c cng b. iu ny cho php ngi bn nh ch hot ng mua bn vi ngi mua nu pht hin ri ro nguy him (mt cc ti sn).(9) Watermarking n cho mt VCR s:Trongtrnghp ngdng ny, mtwatermark nc nhngvo trong video nn MPEG.VCR s tm kim mt watermark c bit xc nh xem liu video ny c th c copy khng hay ch c th c chi thi.3.2.5. Cc c tnh mong mun cho watermark3.2.5.1. Cc c tnh mong mun cho watermark hinTrong cc trng hp ng dng (2) v (3) mc 3.2.4 th cng chia s cc c tnh mong mun chung cho watermark l:1- Watermark l d dng nhn thy2- Watermark khng gy ch nhiu3- Watermark l kh loi b424- Watermark c th c ng dng t ng cho cc nh khc nhau vi s ni bt khng i.c tnh mong mun th 4 l khng d c tha mn. Thc t khi s dng cng watermark cho cc nh khc nhau th cho cc kt qu khc nhau. Watermark c th ni bt trong mt nh ny, nhng li gn nh l n i vi cc nh khc.3.2.5.2. Cc c tnh mong mun cho watermark n yu.Trong cc trng hp ng dng (3) v (4) mc 3.2.4 th cng chia s cc c tnh mong mun cho watermark l:1- Watermark l n i vi quan st con ngi2- Watermark b thay i bi ng dng ca hu ht cc k thut x l nh thng thng3- Kh khn cho mt ngi khng c thm quyn thm vo mt watermark li4- Watermark c th c trch ra nhanh chng bi ngi c thm quyn5- watermark vn tn ti sau khi b ct xn6- Watermark trch ra s cho bit ni cc chnh sa c thc hinS rt kh khn xc nh liu mt nh l hon ton n, bi v s n hin ca n ph thuc vo ngi quan st, nh, v nh c biu din nh th no (bng chiu, inn, di sngno). c tnh3gii quyt slongi rng watermark c th b trch ra t mt nh c nh du v c nhng vo trong mt nh thay th. Do n mong mun rng s rt kh khn cho k ph hoi xc nh ra mt nh c nh du nh th no. Chng ta ng h gii php 43l cc du ch c th c trch ra vi mt chui d liu n (kha) m chng c ct du ring bit trong mt c s d liu mt. 3.2.5.3. Cc c tnh mong mun cho watermark n mnhTrong cc trng hp ng dng (1), (5), (6) v (7) mc 3.2.4 th cng chia s cc c tnh mong mun cho watermark l:1- Watermark l n i vi quan st con ngi2- Watermark khng thay i trong mt nh nhng watermark,thm tr sau khi n c x l bi cc k thut x l nh thng thng3- Watermark l kh pht hin i vi ngi khng c thm quyn.4- Watermark c th c trch ra nhanh chng i vi ngi c thm quyn5- Sau khi mt nh nhng watermark c in v c qut li th watermark vn c th c trch ra. Kt lun: Cc c s l thuyt c trnh by trong Chng ny l c s rt quan trng lun vn tin hnh phn tch thit k v xy dng cc khi thut ton nn nh JPEG v watermarking trong m phng cng nh thc hin bng VHDL v trn FPGA (s c trnh by trong Chng 4). Cc c im ng dng ca watermarking nh s trnh by trong chng ny cho thy watermarking l k thut c tim nng ng dng ln v s pht trin mnh m trong tng lai gn.44CHNG 4: PHN TCH V XY DNG CC KHI THUT TON NN NH V WATERMARKINGCc thut ton chnh cho nn nh l: bin i khng gian mu v tc ly mu mu, DCT v IDCT, lng t ha, qut zigzag, m ha Entropy. Cc thut ton watermarking bao gm thutton watermarking trong minchann v thut ton watermarking trong min nn.4.1. Cc thut ton nn nhMi thut ton nn nh ca JPEG c m t v thc hin theo cc module ring, v thut ton JPEG tng th c tng hp t cc module ring bit.4.1.1. KhiThut ton bin i khng gian muPhng trnh bin i khng gian mu:(4.1)S dng cng c Xilinx System generator thc hin thut ton c th hin trn Hnh 4.1.Hnh 4.1: Khi thut ton RGB to YCbCr45;+ + + + 128 ) ( 713 . 0128 ) ( 564 . 0114 . 0 587 . 0 299 . 0Y R CrY B CbB G R YThut ton yu cu 6 b cng v 4 b nhn. Tr gy ra t cc b cng v b nhn khng phi l vn quan trng trong FPGA. Thut ton cng c th c thc hin d dng bng VHDL.4.1.2. Tc ly mu munh dng video nguyn thy RGB cung cp thng tin v R, G v B trong rng bng tn ging nhau. Thng tin ny c th c lu tr v pht i trong nh dng RGB ny, mc d n khng phi l mt nh dng hiu qu cao. Khoa hc chng minh rng mt ngi khng nhy cm vi chi tit v mu sc nh l chi tit v sng ( chi). S dng bin i khng gian mu bin i RGB sang khng gian mu YCbCr, trong Y l thng tin chi, Cb v Cr nhn c t cc tn hiu hiu s mu. Hn th na rng bng tn y ca Y c th c duy tr, nhng Cb v Cr c ly mu nh hn. iu ny cung cp mt bc x l n gin nhng rt quan trng cho nn nh v video. C 3 nh dng ly mu mu c bn c s dng rng ri trong cc chun nn video l 4:4:4, 4:2:2, 4:2:0. 4.1.2.1. Cc nh dng ly mu mu c bn4:4:4nh dng ny c to ra t RGB, tuy nhin vi mc ch s dng cho cc khi chuyn i, nh dng ny cng c s dng m t YCbCr ti tc ly mu nh RGB. N c s dng cho cc mc ch thu nhn v hin th nh. Cc knh Cb v Cr c ly mu ti cng tc nh tn hiu chi. V vy ti tt c cc v tr pixel u c d liu tn hiu chi v tn hiu mu (Hnh 4.2).46 Hnh 4.2: Biu din ha chun ly mu 4:4:4Trong :O: pixel ch c d liu chiX: pixel ch d liu mu (Cb v Cr) Pixel gm c ng thi d liu chi v d liu muQa trnh to ra nh dng ny l n gin. Mt bus ring c yu cu cho mi Y, Cb v Cr. Khi c d liu u vo, mt tn hiu din_valid nn xut hin cng vi d liu. Tn hiu dout_valid s ging nh tn hiu din_valid, nhng c th b tr mt s chu k ng h (Hnh 4.3)Hnh 4.3: Qa trnh to dnh dng 4:4:44:2:2nh dng ny gm c d liu mu c ly mu con theo chiu ngang. Mi hai mu chi, th c mt cp kt hp mu Cr v Cb. Cc v tr mu c ly mu con c kt hp vi cc mu chi tng ng (Hnh 4.4)47Hnh 4.4: Biu din ha chun 4:2:2S to ra nh dng ny lin quan n vic t Cr v Cb vo mt bus n, v chy bus ny ti tc mu y , t Cr u tin (Hnh 4.5) Hnh 4.5: To nh dng 4:2:24:2:0nh dng 4:2:0 c s dng chnh cho m ha MPEG-2, gm c d liu mu c ly mu con theo c chiu ngang v dc. Mt c tnh thm vo vi nh dng ny l cc pixel mu khng c kt hp vi cc pixel chi. Thc t to ra cc pixel mu, tnh nng lc dc c s dng v v tr hiu qu ca chng t chng trc tip gia cc cp dng tng ng. Ga tr ca chng c ni suy (Hnh 4.6).Hnh 4.6: Biu din ha nh dng 4:2:048S to ra nh dng ny tng t nh s to ra nh dng 4:2:2, ngoi tr mt iu rng ch c cc dng xen k l c gi tr (Hnh 4.6). iu ny l ng cho c tn hiu u vo v u ra. Dout_valid c a ra nh mt tn hiu xc nhn u ra. y cc dng d liu chi c a ra theo th t 0,1,2,3,4,5(0 l dng u tin), cc dng d liu mu u ra c gi tr s c a ra trn cc dng 0,2,4,6,(Hnh 4.7).Hnh 4.7: S to nh dng 4:2:04.1.2.2. Khi chuyn i tc ly mu muS chuyn i gia cc nh dng mu ny c th t c bng cch s dng phng php b lc. Mt vi b chuyn i yu cu lc ch theo chiu H, mt vi ch theo chiu V, v mt vi theo c hai chiu H v V. Trong phm vi ti s dng b chuyn i tc ly mu mu 4:4:4 sang 4:2:0, nn y ch gii thiu b chuyn i 4:4:4to4:2:0.B chuyn i ny l khi x l 2 chiu, thc hin chuyn i xung theo c chiu ngang v chiu dc bi mt h s ca 2. Theo mc nh th iu ny t c bng cch s dng cu trc 6-tap vi 3 tap ngang v 2 tap dc. B lc ny l i xng theo c chiu ngang v dc, v n c phn nh trong cc h s mc nh m tng ng vi [0.0625 0.375 0.0625] v c biu din trong 49nh dng 5 bit bi tp s nguyn [1 6 1], v c lp li cho mi 2 v tr dc. Khi x l c vit bng m VHDL (hnh 4.8a) (da vo IP core ca Xilinx) v c m t khi bng System generator nh trnh by trn Hnh 4.8b. (a)(b)Hnh 4.8: Khi chuyn i 4:4:4to4:2:0Cc h s c s dng nh mt generic cho khi ny l:Num_v_tap: integer :=3;Num_h_tap: integer :=2;Coefs : integer_array:= (a,b,c,d,e,f,);a l h s c s dng cho mu u vo thp nht trong m ca b lc (hnh 4.9). Hnh 4.9: cu hnh h s 4:4:4to4:2:050Trong : mu u vo, X: pixel u ra ch cho m ny.Cc chn tn hiu giao din ca khi:Luma_in: tn hiu chi u voCr_in: tn hiu hiu s mu Cr u voCb_in: tn hiu hiu s mu Cb u voLuma_out: tn hiu chi u ra, n l phin bn tr ca tn hiu chi u vo.Chroma_out: tn hiu mu u ra c ly mu li. CrCb c t trong cng mt rng bng tn v Cr lun lun xut hin trc.Din_valid: tn hiu ny th ging hon ton vi tn hiu hs_in trn cc dng lc. Dout_valid: phin bn tr ca din_valid, cho bit d liu c gi tr ti luma_out v chroma_out.4.1.3. Thut ton bin i cosine ri rc (DCT)Bin i cosine ri rc l mt bin i phc tp. gim phc tp trong tnh ton v lp trnh, cc nh khoa hc tm ra mt phng php tnh DCT nhanh gi l FDCT (Fast DCT).T phng trnh 3.11, cc nh ton hc chng minh c rng:C = T*X*Tt(4.2)Trong :( )'>

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+021 2cos201) , (iNi jNiNj i T(i,j)=(NxN) (4.3)Tt l ma trn chuyn v ca T. F l ma trn cc phn t nh pixels u vo. 51X = F 128,V DCT c thit kt lm vic trn cc gi tr pixel t -128 n 127, nn nu khi u vo F c cc phn t ln hn 128 th ta s thc hin tr i 128 cho mi phn t ca khi. Ma trn X c kch thc ging nh ma trn F, v ma trn cc h s sau bin i DCT (C).4.1.3.1. Tnh ton v xy dng khi DCT-2D 8x8Khi (i,j) =(8x8). Sdngphngphptnhtonbngmytnhcho phng trnh 4.3, ta thu c ma trn T v Tt nh sau: thun tin cho vic tnh ton, thc hin chuyn ma trn h s T v v biu din di dng cc s nguyn nh sau :5211111111111]1

0975 , 0 2778 , 0 4157 , 0 4904 , 0 4904 , 0 4157 , 0 2778 , 0 0975 , 01913 , 0 4619 , 0 4619 , 0 1913 , 0 1913 , 0 4619 , 0 4619 , 0 1913 , 02778 , 0 4904 , 0 0975 , 0 4157 , 0 4157 , 0 0975 , 0 4904 , 0 2778 , 03536 , 0 3536 , 0 3536 , 0 3536 , 0 3536 , 0 3536 , 0 3536 , 0 3536 , 04157 , 0 0975 , 0 4904 , 0 2278 , 0 2778 , 0 4904 , 0 0975 , 0 4157 , 04619 , 0 1913 , 0 1913 , 0 4619 , 0 4619 , 0 1913 , 0 1913 , 0 4619 , 04904 , 0 4157 , 0 2778 , 0 0975 , 0 0975 , 0 2778 , 0 4157 , 0 4904 , 03536 , 0 3536 , 0 3536 , 0 3536 , 0 3536 , 0 3536 , 0 3536 , 0 3536 , 0T11111111111]1

0975 . 0 1913 . 0 2778 . 0 3536 . 0 4157 . 0 4619 . 0 4904 . 0 3536 . 02778 . 0 4619 . 0 4904 . 0 3536 . 0 0975 . 0 1913 . 0 4157 . 0 3536 . 02778 . 0 4619 . 0 4904 . 0 3536 . 0 0975 . 0 1913 . 0 2778 . 0 3536 . 04904 . 0 1913 . 0 4157 . 0 3536 . 0 2778 . 0 4619 . 0 0975 . 0 3536 . 04904 . 0 1913 . 0 4157 . 0 3536 . 0 2778 . 0 4619 . 0 0975 . 0 3536 . 04157 . 0 4619 . 0 0975 . 0 3536 . 0 4904 . 0 1913 . 0 2778 . 0 3536 . 02778 . 0 4619 . 0 4904 . 0 3536 . 0 0975 . 0 1913 . 0 4157 . 0 3536 . 00975 . 0 1913 . 0 2778 . 0 3536 . 0 4157 . 0 4619 . 0 4904 . 0 3536 . 0tT Thut ton DCT v IDCT hai chiu c th t c bng thc hin thut ton mt chiu hai ln, mt ln cho cc hng (theo chiu ngang) v mt ln cho cc ct (theo chiu dc) (Hnh 4.10).S dng phng php x l vc t, u ra C ca b bin i DCT8x8 cho u vo X c tnh theo phng trnh 4.2. Phng trnh ny cng c th c vit nh sau: C=T*Z, trong Z=X*Tt. Ga tr Z c th c tnh ton nh sau: Vi: 5311111111111]1

25 71 71 126 126 106 71 2549 118 118 49 49 118 118 4971 126 25 106 106 25 126 7191 91 91 91 91 91 91 91106 25 126 71 71 126 25 106118 49 49 118 118 49 49 118126 106 71 25 25 71 106 12691 91 91 91 91 91 91 91TOutput Input1-D DCT 1X8B m 8x8Hnh 4.10: Cu trc khi ng d liu 2-D DCT11111111111]1

25 49 71 91 106 118 126 9171 118 126 91 25 49 106 91106 118 25 91 126 49 71 91126 49 106 91 71 118 25 91126 49 106 91 71 118 25 91106 118 25 91 126 49 71 9171 118 126 91 25 49 106 9125 49 71 91 106 118 126 91tT11111111111]1

77 76 75 74 73 72 71 7067 66 65 64 63 62 61 6057 56 55 54 53 52 51 5047 46 45 44 43 42 41 4037 36 35 34 33 32 31 3027 26 25 24 23 22 21 2017 16 15 14 13 12 11 1007 06 05 04 03 02 01 00x x x x x x x xx x x x x x x xx x x x x x x xx x x x x x x xx x x x x x x xx x x x x x x xx x x x x x x xx x x x x x x xXPhng trnh Z = X*Tt c tnh cho tng phn t nh sau:Z(0,0) = 91(x00+x01+x02+x03+x04+x05+x06+x07)Z(0,1) = 126x00 + 106x01 + 71x02 + 25x03 - 25x04 - 71x05 - 106x06 - 126x07= 126(x00-x07) + 106(x01-x06) + 71(x02-x05) + 25(x03-x04)Z(0,2) = 118(x00+x07) + 49(x01+x06) 49(x02+x05) 118(x03+x04)Z(0,3) = 106(x00-x07) - 25(x01-x06) 126(x02-x05) - 71(x03-x04) Z(0,4) = 91(x00+x07) -91(x01+x06) - 91(x02+x05) + 91(x03+x04)Z(0,5) = 71(x00-x07) -126(x01-x06) + 25(x02-x05) + 106(x03-x04)Z(0,6) = 49(x00+x07) 118(x01+x06) + 118(x02+x05) - 49(x03+x04)Z(0,7) = 25(x00-x07) - 71(x01-x06) + 106(x02-x05) -126(x03-x04)Tng qut:Z(k,0) = 91(xk0+xk1+xk2+xk3+xk4+xk5+xk6+xk7)Z(k,1) = 126(xk0-xk7) + 106(xk1-xk6) + 71(xk2-xk5) + 25(xk3-xk4)Z(k,2) = 118(xk0+xk7) + 49(xk1+xk6) 49(xk2+xk5) 118(xk3+xk4)Z(k,3) = 106(xk0-xk7) - 25(xk1-xk6) 126(xk2-xk5) - 71(xk3-xk4) Z(k,4) = 91(xk0+xk7) -91(xk1+xk6) - 91(xk2+xk5) + 91(xk3+xk4)54Z(k,5) = 71(xk0-xk7) -126(xk1-xk6) + 25(xk2-xk5) + 106(xk3-xk4)Z(k,6) = 49(xk0+xk7) 118(xk1+xk6) + 118(xk2+xk5) - 49(xk3+xk4)Z(k,7) = 25(xk0-xk7) - 71(xk1-xk6) + 106(xk2-xk5) -126(xk3-xk4)Trong k=0,1,...,7Mi phn t hng u tin ca ma trn u vo X c nhn vi mi phn t ct u tin ca ma trn Tt v cng li c gi tr u tin Z00 ca ma trn trung gian Z. c Z01, mi phn t ca hng 0 ma trn X c nhn vi mi phn t hng u tin ca Ttv sau cng chng li. Quan st cc phng trnh tnh ton trn ta thy u vo x00 c nhn vi tt c cc phn t hng u tin ca Tt, u vo x01 c nhn vi tt c cc h s hng th 2 ca Tt, v tip tc nh vy.Cc tnh ton c thc hin bng cch s dng 8 b nhn v lu tr cc h s trong cc ROM. Ti xung ng h u tin, 8 u vo t x00 ti x07 c nhn v 8 gi tr ca ct 1, kt qu cho ra 8 sn phm P00_0 ti P00_7. Ti xung ng h th 8, 8 u vo c nhn vi 8 gi tr ct 8 v cho kt qu 8 sn phm l P07_0 ti P07_7. T cc phng trnh cho tnh Z, cc gi tr trung gian cho hng u tin ca Z c tnh nh sau:Z00 = P00_0 + P00_1 + P00_2 + P00_3 + P00_4 + P00_5 + P00_6 + P00_7Z01 = P01_0 + P01_1 + P01_2 + P01_3 + P01_4 + P01_5 + P01_6 + P01_7Zij = Pij_0 + Pij_1 + Pij_2 + Pij_3 + Pij_4 + Pij_5 + Pij_6 + Pij_7Trong i=0->7 l s hng ca ma trn X v j=0->7 l s ct ca ma trn Tt. Cc gi tr trung gian cho hng th 2 ca Z l Z1k, c tnh ton bi s dng cc gi tr P1k. Tnh tun t s dng cc phng trnh ny ta s thu c ma trn Z 8x8.55S khi thc hin 1D-DCT 8x8 c th hin hnh 4.11. ADDERADDSUBADDSUBADDSUBADDSUBXXXX91126118106917149259110649 -25-91-126-118-719171 -49 -126 -91251181069125 -118-7191106 -49 -1267 kx1 kx6 kx2 kx5 kx3 kx4 kxkoxToggleFlop1 =Add0 =Sub) 7 0 ( > KZHnh 4.11: S khi thc hin DCT 1-D (k: 0-7)Tn hiu iu khin Toggle c tn s bng tn s clk vo khi DCT. Nu Toggle bng 1 th Add/Sub l b cng, bng 0 l b tr. hnh dung ra cch ghi dch v thc hin php tnh s hc a ra gi tr Zk, xem xt s thc hin di y:Chu k1 2 3 4 5 6 7 8 9 10 11 12 1356Xk0Chn thm gi tr 0 trnh trn duxk7xk0X l duNhn vi gi tr ma trn h s Ta ra kt qu ZoutXk1Xk0Xk2Xk1Xk0xk6xk0Xk3Xk2Xk1Xk0Xk4Xk3Xk2Xk1Xk0xk5xk2Xk5Xk4Xk3Xk2Xk1Xk0Xk6Xk5Xk4Xk3Xk2Xk1Xk0xk4xk3Xk7Xk6Xk5Xk4Xk3Xk2Xk1Xk0Quan st trn ta c th thy cn t nht 14 chu k xung nhp a gi tr Zout ra ngoi. Tip theo lu y 64 gi tr ca Z vo Ram. Nh vy cn t nht l 14+64=77chu k xung nhp a ra phn t u tin ca ma trn Z theo hng thc hin php tnh 1D-DCT ln th 2 c DCT-2D. Khi cc gi tr Z c tnh, cc gi tr Y ca bin i DCT 2-D c tnh theo biu thc Y = T*Z. Vi cc ma trn T v Z: 5711111111111]1

25 71 71 126 126 106 71 2549 118 118 49 49 118 118 4971 126 25 106 106 25 126 7191 91 91 91 91 91 91 91106 25 126 71 71 126 25 106118 49 49 118 118 49 49 118126 106 71 25 25 71 106 12691 91 91 91 91 91 91 91T11111111111]1

77 76 75 74 73 72 71 7067 66 65 64 63 62 61 6057 56 55 54 53 52 51 5047 46 45 44 43 42 41 4037 36 35 34 33 32 31 3027 26 25 24 23 22 21 2017 16 15 14 13 12 11 1007 06 05 04 03 02 01 00z z z z z z z zz z z z z z z zz z z z z z z zz z z z z z z zz z z z z z z zz z z z z z z zz z z z z z z zz z z z z z z zZMi phn t hng u tin trong ma trn h s T c nhn vi mi phn t trong ct u tin ca ma trn Z v sau cng chng li vi nhau c gi tr u tin Y00 ca ma trn u ra Y. c Y01 mi phn t ca hng 0 ma trn T c nhn vi mi phn t ca ct u tin ca Z v sau c cng li ging nh trn. Thc hin nhn hng k ca T vi ct 0 ca Z kt qu cho h s YK0. Tt c cc phn t trong hng u tin ca ma trn Z c nhn vi tt c cc phn t trong ct u tin ca ma trn T.11111111111]1

77 76 75 74 73 72 71 7067 66 65 64 63 62 61 6057 56 55 54 53 52 51 5047 46 45 44 43 42 41 4037 36 35 34 33 32 31 3027 26 25 24 23 22 21 2017 16 15 14 13 12 11 1007 06 05 04 03 02 01 009191919191919191z z z z z z z zz z z z z z z zz z z z z z z zz z z z z z z zz z z z z z z zz z z z z z z zz z z z z z z zz z z z z z z zCc tnh ton c thc hin bng cch s dng 8 b nhn v lu tr cc h s trong cc RAM. S khi thc hin bin i DCT 2-D c th hin trn hnh 4.1258ADDERADDSUBADDSUBADDSUBADDSUBXXXX91126118106917149259110649 -25-91-126-118-719171 -49 -126 -91251181069125 -118-7191106 -49 -1267 kz1 kz6 kz2 kz5 kz3 kz4 kzkoz) 7 0 ( > KYToggleFlop1 = Add0 = SubHnh 4.12: S khi thc hin DCT 2-D (K: 0 -> 7) php bin i DCT chiu th 2 ny cn t nht 16 chu k xung nhp a ra phn t u tin ca ma trn u ra Y theo th t hng.Tng thi gian cn thit a ra gi tr Y u tin k t lc a vo gi tr X u tin l 78 + 16 = 94 chu k xung nhp.Tm tt qu trnh thc hin bin i DCT 2D 8x8 qua biu dng thut ton (Hnh 4.13)59Khi DCT 2D 8x8 c vit bng m VHDL (Hnh 4.14a) v c m ta bng System generator (Hnh 4.14b). (a)(b)60NNChuyn d liu gc 8x8 u vo vo b m1-D 1X8 DCTCc h s DCT hng 1 vo b mHng cui cng1-D 1x8 DCTCc h s DCT ct 1 vo b mCt cui cngHng tip theoCt tip theoKt thcHnh 4.13: Biu dng thut ton 2-D DCTD C T-2D8x8r d y_i nx i nd c t_2d_8x8r d y_o u tHnh 4.14: Khi thc hin thut ton DCT-2D 8x8Cc chn tn hiu giao din ca khi:CLK: tn hiu xung nhp ca h thng.RST: tn hiu reset ca h thng, mc tch cc RST=1.Rdy_in: tn hiu iu khin bo c tn hiu video vo tch cc cc khi x l, mc tch cc rdy_in=1.Xin(7:0): L tn hiu data 8 bits c biu din di dng m b 2. Khi tn hiu rdy_in=1 th tn hiu xin(7:0) mi c x l.Rdy_out: tn hiu iu khin cho bit bt u xut hin phn t u tin h s DCT 2-D u ra. N bo cho khi sau l ang c tn hiu video tch cc. Tn hiu rdy_out tr so vi rdy_in l 154 chu k xung nhp. Mc tch cc u ra l rdy_out=1.Dct_2d_8x8(11:0): tn hiu data 12 bits c biu din di dng module (1 bit du v 11 bit d liu data). Tn hiu ny c a ra sau 94 chy k xung.4.1.3.2. Tnh ton v xy dng khi bin i DCT 2-D 16x16Khi (i,j) =(16x16) Sdngphngphptnhtonbngmytnhcho phng trnh 4.3, ta thu c ma trn T cho DCT 2-D 16x16 nh sau:6111111111111111111111111]1

0.0347 - 0.1026 0.1667 - 0.2243 0.2733 - 0.3118 0.3383 - 0.3519 0.3519 - 0.3383 0.3118 - 0.2733 0.2243 - 0.1667 0.1026 - 0.03470.0690 0.1964 - 0.2940 0.3468 - 0.3468 0.2940 - 0.1964 0.0690 - 0.0690 - 0.1964 0.2940 - 0.3468 0.3468 - 0.2940 0.1964 - 0.06900.1026 - 0.2733 0.3519 - 0.3118 0.1667 - 0.0347 - 0.2243 0.3383 - 0.3383 0.2243 - 0.0347 0.1667 0.3118 - 0.3519 0.2733 - 0.10260.1353 0.3266 - 0.3266 0.1353 - 0.1353 - 0.3266 0.3266 - 0.1353 0.1353 0.3266 - 0.3266 0.1353 - 0.1353 - 0.3266 0.3266 - 0.13530.1667 - 0.3519 0.2243 - 0.1026 - 0.3383 0.2733 - 0.0347 - 0.3118 0.3118 - 0.0347 0.2733 0.3383 - 0.1026 0.2243 0.3519 - 0.16670.1964 0.3468 - 0.0690 0.2940 0.2940 - 0.0690 - 0.3468 0.1964 - 0.1964 - 0.3468 0.0690 - 0.2940 - 0.2940 0.0690 0.3468 - 0.19640.2243 - 0.3118 0.1026 0.3519 - 0.0347 0.3383 0.1667 - 0.2733 - 0.2733 0.1667 0.3383 - 0.0347 - 0.3519 0.1026 - 0.3118 - 0.22430.2500 0.2500 - 0.2500 - 0.2500 0.2500 0.2500 - 0.2500 - 0.2500 0.2500 0.2500 - 0.2500 - 0.2500 0.2500 0.2500 - 0.2500 - 0.25000.2733 - 0.1667 0.3383 0.0347 - 0.3519 - 0.1026 - 0.3118 0.2243 0.2243 - 0.3118 - 0.1026 0.3519 0.0347 0.3383 - 0.1667 - 0.27330.2940 0.0690 - 0.3468 - 0.1964 - 0.1964 0.3468 0.0690 0.2940 - 0.2940 - 0.0690 0.3468 0.1964 0.1964 - 0.3468 - 0.0690 - 0.29400.3118 - 0.0347 - 0.2733 0.3383 0.1026 0.2243 - 0.3519 - 0.1667 - 0.1667 0.3519 0.2243 0.1026 - 0.3383 - 0.2733 - 0.0347 0.31180.3266 0.1353 0.1353 - 0.3266 - 0.3266 - 0.1353 - 0.1353 0.3266 0.3266 0.1353 0.1353 - 0.3266 - 0.3266 - 0.1353 - 0.1353 0.32660.3383 - 0.2243 - 0.0347 - 0.1667 0.3118 0.3519 0.2733 0.1026 0.1026 - 0.2733 - 0.3519 - 0.3118 - 0.1667 - 0.0347 0.2243 0.33830.3468 0.2940 0.1964 0.0690 0.0690 - 0.1964 - 0.2940 - 0.3468 - 0.3468 - 0.2940 - 0.1964 - 0.0690 - 0.0690 0.1964 0.2940 0.34680.3519 - 0.3383 - 0.3118 - 0.2733 - 0.2243 - 0.1667 - 0.1026 - 0.0347 - 0.0347 0.1026 0.1667 0.2243 0.2733 0.3118 0.3383 0.35190.2500 0.2500 0.2500 0.2500 0.2500 0.2500 0.2500 0.2500 0.2500 0.2500 0.2500 0.2500 0.2500 0.2500 0.2500 0.2500T thun tin cho vic tnh ton, thc hin chuyn ma trn h s T v v biu din di dng cc s nguyn nh sau:11111111111111111111111]1

9 - 26 43 - 57 70 - 80 87 - 90 90 - 87 80 - 70 57 - 43 26 - 918 50 - 75 89 - 89 75 - 50 18 - 18 - 50 75 - 89 89 - 75 50 - 1826 - 70 90 - 80 43 - 9 - 57 87 - 87 57 - 9 43 80 - 90 70 - 2635 84 - 84 35 - 35 - 84 84 - 35 35 84 - 84 35 - 35 - 84 84 - 3543 - 90 57 - 26 - 87 70 - 9 - 80 80 - 9 70 87 - 26 57 90 - 4350 89 - 18 75 75 - 18 - 89 50 - 50 - 89 18 - 75 - 75 18 89 - 5057 - 80 26 90 - 9 87 43 - 70 - 70 43 87 - 9 - 90 26 - 80 - 5764 64 - 64 - 64 64 64 - 64 - 64 64 64 - 64 - 64 64 64 - 64 - 6470 - 43 87 9 - 90 - 26 - 80 57 57 - 80 - 26 90 9 87 - 43 - 7075 18 - 89 - 50 - 50 89 18 75 - 75 - 18 89 50 50 - 89 - 18 - 7580 - 9 - 70 87 26 57 - 90 - 43 - 43 90 57 26 - 87 - 70 - 9 8084 35 35 - 84 - 84 - 35 - 35 84 84 35 35 - 84 - 84 - 35 - 35 8487 - 57 - 9 - 43 80 90 70 26 26 - 70 - 90 - 80 - 43 - 9 57 8789 75 50 18 18 - 50 - 75 - 89 - 89 - 75 - 50 - 18 - 18 50 75 8990 - 87 - 80 - 70 - 57 - 43 - 26 - 9 - 9 26 43 57 70 80 87 9064 64 64 64 64 64 64 64 64 64 64 64 64 64 64 64TThut ton DCT 2D 16x16 c th t c bng thc hin thut ton mt chiu hai ln, mt ln cho cc hng (theo chiu ngang) v mt ln cho cc ct (theo chiu dc) (Hnh 4.15).S dng phng php x l vc t, u ra C ca b bin i DCT16x16 cho u vo X c tnh theo phng trnh 4.2. Phng trnh ny cng c th c vit nh sau: C =T*Z, trong Z=X*Tt. Ga tr Z c th c tnh ton nh sau, Vi: 62Output Input1-D DCT 1X16B m 16x16Hnh 4.15: Cu trc khi ng d liu 2-D DCT 16x1611111111111111111111111]1

9 - 18 26 - 35 43 - 50 57 - 64 70 - 75 80 - 84 87 - 89 90 - 6426 50 - 70 84 - 90 89 - 80 64 - 43 18 - 9 - 35 57 - 75 87 - 6443 - 75 90 - 84 57 - 18 26 64 - 87 89 - 70 35 - 9 - 50 80 - 6457 89 - 80 35 - 26 - 75 90 - 64 9 - 50 - 87 84 - 43 18 70 - 6470 - 89 43 - 35 - 87 75 - 9 64 90 - 50 26 84 - 80 18 - 57 - 6480 75 - 9 - 84 70 - 18 - 87 64 - 26 - 89 57 - 35 - 90 50 - 43 - 6487 - 50 57 84 - 9 - 89 43 - 64 - 80 18 90 - 35 70 75 - 26 - 6490 18 - 87 - 35 80 50 - 70 - 64 57 75 - 43 - 84 26 89 - 9 - 6490 - 18 - 87 35 80 - 50 - 70 64 57 - 75 - 43 84 26 - 89 - 9 6487 50 57 - 84 - 9 89 43 64 - 80 - 18 90 35 70 - 75 - 26 6480 - 75 - 9 84 70 18 - 87 - 64 - 26 89 57 35 - 90 - 50 - 43 6470 89 43 35 - 87 - 75 - 9 - 64 90 50 26 - 84 - 80 - 18 - 57 6457 - 89 - 80 - 35 - 26 75 90 64 9 50 - 87 - 84 - 43 - 18 70 6443 75 90 84 57 18 26 - 64 - 87 - 89 - 70 - 35 - 9 50 80 6426 - 50 - 70 - 84 - 90 - 89 - 80 - 64 - 43 - 18 - 9 35 57 75 87 649 18 26 35 43 50 57 64 70 75 80 84 87 89 90 64tT6311111111111111111111111]1

1515 1514 1513 1512 1511 1510 159 158 157 156 155 154 153 152 151 1501415 1414 1413 1412 1411 1410 149 148 147 146 145 144 143 142 141 1401315 1314 1313 1312 1311 1310 139 138 137 136 135 134 133 132 131 1301215 1214 1213 1212 1211 1210 129 128 127 126 125 124 123 122 121 1201115 1114 1113 1112 1111 1110 119 118 117 116 115 114 113 112 111 1101015 1014 1013 1012 1011 1010 109 108 107 106 105 104 103 102 101 100915 914 913 912 911 910 99 98 97 96 95 94 93 92 91 90815 814 813 812 811 810 89 88 87 86 85 84 83 82 81 80715 714 713 712 711 710 79 78 77 76 75 74 73 72 71 70615 614 613 612 611 610 69 68 67 66 65 64 63 62 61 60515 514 513 512 511 510 59 58 57 56 55 54 53 52 51 50415 414 413 412 411 410 49 48 47 46 45 44 43 42 41 40315 314 313 312 311 310 39 38 37 36 35 34 33 32 31 30215 214 213 212 211 210 29 28 27 26 25 24 23 22 21 20115 114 123 112 111 110 19 18 17 16 15 14 13 12 11 10015 014 013 012 011 010 09 08 07 06 05 04 03 02 01 00x x x x x x x x x x x x x x x xx x x x x x x x x x x x x x x xx x x x x x x x x x x x x x x xx x x x x x x x x x x x x x x xx x x x x x x x x x x x x x x xx x x x x x x x x x x x x x x xx x x x x x x x x x x x x x x xx x x x x x x x x x x x x x x xx x x x x x x x x x x x x x x xx x x x x x x x x x x x x x x xx x x x x x x x x x x x x x x xx x x x x x x x x x x x x x x xx x x x x x x x x x x x x x x xx x x x x x x x x x x x x x x xx x x x x x x x x x x x x x x xx x x x x x x x x x x x x x x xXPhng trnh Z = X*Tt c tnh cho tng phn t nh sau:Z(0,0)= 64(x00+x01+x02+x03+x04+x05+x06+x07+x08+x09+x010+x011+x012+x013+x014+x015)Z(0,1)=90x00+87x01+80x02+70x03+57x04+43x05+26x06+9x07-9x08-26x09-43x010-57x011-70x012-80x013-87x014-90x015=90(x00-x015)+87(x01-x014)+80(x02-x013)+70(x03-x012)+57(x04-x011)+ 43(x05-x010)+26(x06-x09)+9(x07-x08)Z(0,2)=89(x00+x015)+75(x01+x014)+50(x02+x013)+18(x03+x012)-18(x04+x011)- 50(x05+x010)-75(x06+x09)-89(x07+x08)Z(0,3)=87(x00-x015)+57(x01-x014)+9(x02-x013)-43(x03-x012)-80(x04-x011)-90(x05-x010)- 70(x06-x09)-26(x07-x08)Z(0,4)=84(x00+x015)+35(x01+x014)-35(x02+x013)-84(x03+x012)-84(x04+x011)-35(x05+x010)+35(x06+x09)+84(x07+x08)Z(0,5)=80(x00-x015)+9(x01-x014)-70(x02-x013)-87(x03-x012)-26(x04-x011)+57(x05-x010)+90(x06-x09)+43(x07-x08)Z(0,6)=75(x00+x015)-18(x01+x014)-89(x02+x013)-50(x03+x012)+50(x04+x011)+ 89(x05+x010)+18(x06+x09)-75(x07+x08)Z(0,7)=70(x00-x015)-43(x01-x014)-87(x02-x013)+9(x03-x012)+90(x04-x011)+26(x05-x010)-80(x06-x09)-57(x07-x08)Z(0,8)=64(x00+x015)-64(x01+x014)-64(x02+x013)+64(x03+x012)+64(x04+x011)-64(x05+x010)-64(x06+x09)+64(x07+x08)Z(0,9)=57(x00-x015)-80(x01-x014)-26(x02-x013)+90(x03-x012)-9(x04-x011)-87(x05-x010)+ 43(x06-x09)-70(x07-x08)Z(0,10)=50(x00+x015)-89(x01+x014)+18(x02+x013)+75(x03+x012)-75(x04+x011)-18(x05+x010)+89(x06+x09)-50 (x07+x08)64Z(0,11)=43(x00-x015)-90(x01-x014)+57(x02-x013)+26(x03-x012)-87(x04-x011)+70(x05-x010)+ 9(x06-x09)-80(x07-x08)Z(0,12)=35(x00+x015)-84(x01+x014)+84(x02+x013)-35(x03+x012)-35(x04+x011)+84(x05+x010)-84(x06+x09)+35 (x07+x08)Z(0,13)=26(x00-x015)-70(x01-x014)+90(x02-x013)-80(x03-x012)+43(x04-x011)+9(x05-x010)- 57(x06-x09)+87(x07-x08)Z(0,14)=18(x00+x015)-50(x01+x014)+75(x02+x013)-89(x03+x012)+89(x04+x011)-75(x05+x010)+50(x06+x09)-18(x07+x08)Z(0,15)=9(x00-x015)-26(x01-x014)+43(x02-x013)-57(x03-x012)+70(x04-x011)-80(x05-x010)+ 87(x06-x09)-90(x07-x08)Tng qut:Z(k,0)= 64(xk0+xk1+xk2+xk3+xk4+xk5+xk6+xk7+xk8+xk9+xk10+xk11+xk12+xk13+xk14+xk15)Z(k,1)=90(xk0-xk15)+87(xk1-xk14)+80(xk2-xk13)+70(xk3-xk12)+57(xk4-xk11)+ 43(xk5-xk10)+26(xk6-xk9)+9(xk7-xk8)Z(k,2)=89(xk0+xk15)+75(xk1+xk14)+50(xk2+xk13)+18(xk3+xk12)-18(xk4+xk11)- 50(xk5+xk10)-75(xk6+xk9)-89(xk7+xk8)Z(k,3)=87(xk0-xk15)+57(xk1-xk14)+9(xk2-xk13)-43(xk3-xk12)-80(xk4-xk11)-90(xk5-xk10)- 70(xk6-xk9)-26(xk7-xk8)Z(k,4)=84(xk0+xk15)+35(xk1+xk14)-35(xk2+xk13)-84(xk3+xk12)-84(xk4+xk11)-35(xk5+xk10)+35(xk6+xk9)+84(xk7+xk8)Z(k,5)=80(xk0-xk15)+9(xk1-xk14)-70(xk2-xk13)-87(xk3-xk12)-26(xk4-xk11)+57(xk5-xk10)+90(xk6-xk9)+43(xk7-xk8)Z(k,6)=75(xk0+xk15)-18(xk1+xk14)-89(xk2+xk13)-50(xk3+xk12)+50(xk4+xk11)+ 89(xk5+xk10)+18(xk6+xk9)-75(xk7+xk8)65Z(k,7)=70(xk0-xk15)-43(xk1-xk14)-87(xk2-xk13)+9(xk3-xk12)+90(xk4-xk11)+26(xk5-xk10)-80(xk6-xk9)-57(xk7-xk8)Z(k,8)=64(xk0+xk15)-64(xk1+xk14)-64(xk2+xk13)+64(xk3+xk12)+64(xk4+xk11)-64(xk5+xk10)-64(xk6+xk9)+64(xk7+xk8)Z(k,9)=57(xk0-xk15)-80(xk1-xk14)-26(xk2-xk13)+90(xk3-xk12)-9(xk4-xk11)-87(xk5-xk10)+ 43(xk6-xk9)-70(xk7-xk8)Z(k,10)=50(xk0+xk15)-89(xk1+xk14)+18(xk2+xk13)+75(xk3+xk12)-75(xk4+xk11)-18(xk5+xk10)+89(xk6+xk9)-50 (xk7+xk8)Z(k,11)=43(xk0-xk15)-90(xk1-xk14)+57(xk2-xk13)+26(xk3-xk12)-87(xk4-xk11)+70(xk5-xk10)+ 9(xk6-xk9)-80(xk7-xk8)Z(k,12)=35(xk0+xk15)-84(xk1+xk14)+84(xk2+xk13)-35(xk3+xk12)-35(xk4+xk11)+84(xk5+xk10)-84(xk6+xk9)+35 (xk7+xk8)Z(k,13)=26(xk0-xk15)-70(xk1-xk14)+90(xk2-xk13)-80(xk3-xk12)+43(xk4-xk11)+9(xk5-xk10)- 57(xk6-xk9)+87(xk7-xk8)Z(k,14)=18(xk0+xk15)-50(xk1+xk14)+75(xk2+xk13)-89(xk3+xk12)+89(xk4+xk11)-75(xk5+xk10)+50(xk6+xk9)-18(xk7+xk8)Z(k,15)=9(xk0-xk15)-26(xk1-xk14)+43(xk2-xk13)-57(xk3-xk12)+70(xk4-xk11)-80(xk5-xk10)+ 87(xk6-xk9)-90(xk7-xk8)Trong k=0,1,2,...,15Mi phn t hng u tin ca ma trn u vo X(16x16) c nhn vi mi phn t ct u tin ca ma trn Tt(16x16) v cng li c gi tr u tin Z00 ca ma trn trung gian Z(16x16). c Z01, mi phn t ca hng 0 ma trn X(16x16) c nhn vi mi phn t hng u tin ca Tt(16x16) v sau cng chng li. Quan st cc phng trnh tnh ton trn ta thy u vo 66x00 c nhn vi tt c cc phn t hng u tin ca Tt(16x16), u vo x01 c nhn vi tt c cc h s hng th 2 ca Tt(16x16), v tip tc nh vy.Cc tnh ton c thc hin bng cch s dng 16 b nhn v lu tr cc h s trong cc RAM. Ti xung ng h u tin, 16 u vo t x00ti x015c nhn v 16 gi tr ca ct 1, kt qu cho ra 16 sn phm P00_0 ti P00_15. Ti xung ng h th 16, 16 u vo c nhn vi 16 gi tr ct 16 v cho kt qu 16 sn phm l P015_0ti P015_15. T cc phng trnh cho tnh Z, cc gi tr trung gian cho hng u tin ca Z c tnh nh sau:Z00 = P00_0 + P00_1 + P00_2 + P00_3 + P00_4 + P00_5 + P00_6 + P00_7+ P00_8 + P00_9 + P00_10 + P00_11 + P00_12 + P00_13 + P00_14 + P00_15Z01 = P01_0 + P01_1 + P01_2 + P01_3 + P01_4 + P01_5 + P01_6 + P01_7+ P00_8 + P00_9 + P00_10 + P00_11 + P00_12 + P00_13 + P00_14 + P00_15Zij = Pij_0 + Pij_1 + Pij_2 + Pij_3 + Pij_4 + Pij_5 + Pij_6 + Pij_7+ Pij_8 + Pij_9 + Pij_10 + Pij_11 + Pij_12 + Pij_13 + Pij_14 + Pij_15Trong i=0->15 l s hng ca ma trn X(16x16) v j=0->15 l s ct ca ma trn Tt(16x16). Cc gi tr trung gian cho hng th 2 ca Z l Z1k, c tnh ton bi s dng cc gi tr P1k. Tnh tun t s dng cc phng trnh ny ta s thu c ma trn Z (16x16).S khi thc hin 1D-DCT 16x16 c th hin trn Hnh 4.16.67ADDERADDSUBADDSUBADDSUBADDSUBXXXX64 90 89 87 84 80 75 70 64 57 50 43 35 26 18 964 87 75 57 35 9-18-43-64-80-89-90-84-70-50-2664 80 50 9-35-70-89-87-64-26 18 57 84 90 75 4364 70 18-43-84-87-50 9 64 90 75 26-35-80-89-5715 kx1 kx14 kx2 kx13 kx3 kx12 kxkoxToggleFlop1=Add0=Sub) 15 0 ( > KZADDSUBX64 57-18-80 -84-26 50 90 64-9-75-87-35 43 89 70ADDSUBX64 43 50-90 35 57 89 26-64-87 18 70 84 9 75-805 kx10 kxADDSUBX64 26-75 70 35 90 18 80 64 43 89 9 84 57 50 876 kx9 kxADDSUBX64 9-89-26 84 43-75-57 64-70-50-80 35 87-18-907 kx8 kx4 kx11 kxHnh 4.16: S khi thc hin DCT-1D 16x1668Tn hiu iu khin Toggle c tn s bng tn s clk vo khi DCT 16x16. Nu Toggle bng 1 th Add/Sub l b cng, bng 0 l b tr. hnh dung ra cch ghi dch v thc hin php tnh s hc a ra gi tr Zk, xem xt s thc hin di y:Chu k1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 2021 22 23 2425Xk0Chn thm gi tr 0 trnh trn duxk0xk15X l duNhn vi gi tr ma trn h s T4 b cng ni tipa ra kt qu ZoutXk1 Xk0Xk2 Xk1 Xk0xk1xk14Xk3 Xk2 Xk1 Xk0Xk4 Xk3 Xk2 Xk1 Xk0xk2xk13Xk5 Xk4 Xk3 Xk2 Xk1 Xk0Xk6 Xk5 Xk4 Xk3 Xk2 Xk1 Xk0xk3xk12Xk7 Xk6 Xk5 Xk4 Xk3 Xk2 Xk1 Xk0Xk8 Xk7 Xk6 Xk5 Xk4 Xk3 Xk2 Xk1 Xk0xk4xk11Xk9 Xk8 Xk7 Xk6 Xk5 Xk4 Xk3 Xk2 Xk1 Xk0Xk10 Xk9 Xk8 Xk7 Xk6 Xk5 Xk4 Xk3 Xk2 Xk1 Xk0xk5xk10Xk11 Xk10 Xk9 Xk8 Xk7 Xk6 Xk5 Xk4 Xk3 Xk2 Xk1 Xk0Xk12 Xk11 Xk10 Xk9 Xk8 Xk7 Xk6 Xk5 Xk4 Xk3 Xk2 Xk1 Xk0xk6xk9Xk13 Xk12 Xk11 Xk10 Xk9 Xk8 Xk7 Xk6 Xk5 Xk4 Xk3 Xk2 Xk1 Xk0Xk14 Xk13 Xk12 Xk11 Xk10 Xk9 Xk8 Xk7 Xk6 Xk5 Xk4 Xk3 Xk2 Xk1 Xk0xk7xk8Xk15 Xk14 Xk13 Xk12 Xk11 Xk10 Xk9 Xk8 Xk7 Xk6 Xk5 Xk4 Xk3 Xk2 Xk1 Xk0Quan st trn ta c th thy cn t nht 26 chu k xung nhp a gi tr Zout ra ngoi. Tip theo lu y 16x16=256 gi tr ca Z vo Ram. Nh vy cn t nht l 26+256=282 chu k xung nhp a ra phn t u tin ca ma trn Z theo hng thc hin php tnh 1D-DCT ln th 2 c DCT-2D. Khi cc gi tr Z c tnh, cc gi tr Y ca bin i DCT 2-D c tnh theo biu thc Y = T*Z.Vi ma trn Z thu c sau bin i DCT-1D 16x16:6911111111111111111111111]1

1515 1514 1513 1512 1511 1510 159 158 157 156 155 154 153 152 151 1501415 1414 1413 1412 1411 1410 149 148 147 146 145 144 143 142 141 1401315 1314 1313 1312 1311 1310 139 138 137 136 135 134 133 132 131 1301215 1214 1213 1212 1211 1210 129 128 127 126 125 124 123 122 121 1201115 1114 1113 1112 1111 1110 119 118 117 116 115 114 113 112 111 1101015 1014 1013 1012 1011 1010 109 108 107 106 105 104 103 102 101 100915 914 913 912 911 910 99 98 97 96 95 94 93 92 91 90815 814 813 812 811 810 89 88 87 86 85 84 83 82 81 80715 714 713 712 711 710 79 78 77 76 75 74 73 72 71 70615 614 613 612 611 610 69 68 67 66 65 64 63 62 61 60515 514 513 512 511 510 59 58 57 56 55 54 53 52 51 50415 414 413 412 411 410 49 48 47 46 45 44 43 42 41 40315 314 313 312 311 310 39 38 37 36 35 34 33 32 31 30215 214 213 212 211 210 29 28 27 26 25 24 23 22 21 20115 114 113 112 111 110 19 18 17 16 15 14 13 12 11 10015 014 013 012 011 010 09 08 07 06 05 04 03 02 01 00z z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zZMi phn t hng u tin trong ma trn h s T(16x16) c nhn vi mi phn t trong ct u tin ca ma trn Z(16x16) v sau cng chng li vi nhau c gi tr u tin Y00 ca ma trn u ra Y. c Y01 mi phn t ca hng 0 ma trn T c nhn vi mi phn t ca ct u tin ca Z v sau c cng li ging nh trn. Thc hin nhn hng k ca T vi ct 0 ca Z kt qu cho h s YK0. Tt c cc phn t trong hng u tin ca ma trn Z c nhn vi tt c cc phn t trong ct u tin ca ma trn T.7011111111111111111111111]1

1515 1514 1513 1512 1511 1510 159 158 157 156 155 154 153 152 151 1501415 1414 1413 1412 1411 1410 149 148 147 146 145 144 143 142 141 1401315 1314 1313 1312 1311 1310 139 138 137 136 135 134 133 132 131 1301215 1214 1213 1212 1211 1210 129 128 127 126 125 124 123 122 121 1201115 1114 1113 1112 1111 1110 119 118 117 116 115 114 113 112 111 1101015 1014 1013 1012 1011 1010 109 108 107 106 105 104 103 102 101 100915 914 913 912 911 910 99 98 97 96 95 94 93 92 91 90815 814 813 812 811 810 89 88 87 86 85 84 83 82 81 80715 714 713 712 711 710 79 78 77 76 75 74 73 72 71 70615 614 613 612 611 610 69 68 67 66 65 64 63 62 61 60515 514 513 512 511 510 59 58 57 56 55 54 53 52 51 50415 414 413 412 411 410 49 48 47 46 45 44 43 42 41 40315 314 313 312 311 310 39 38 37 36 35 34 33 32 31 30215 214 213 212 211 210 29 28 27 26 25 24 23 22 21 20115 114 113 112 111 110 19 18 17 16 15 14 13 12 11 10015 014 013 012 011 010 09 08 07 06 05 04 03 02 01 0064646464646464646464646464646464z z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zz z z z z z z z z z z z z z z zCc tnh ton c thc hin bng cch s dng 16 b nhn v lu cc h s vo cc Ram. S khi thc hin bin i DCT-2D 16x16 c th hin trn Hnh 4.17. php bin i DCT chiu th 2 ny cn t nht 26 +2(1 ghi v 1 c Ram) =28 chu k xung nhp a ra phn t u tin ca ma trn u ra Y theo th t hng.Tng thi gian cn thit a ra gi tr Y u tin k t lc a vo gi tr X u tin l 282 + 28 = 310 chu k xung nhp.71ADDERADDSUBADDSUBADDSUBADDSUBXXXX64 90 89 8784 80 75 70 64 57 50 43 35 2618 964 87 75 57 35 9-18-43-64-80-89-90-84-70-50-2664 80 50 9-35-70-89-87-64-26 18 57 84 90 75 4364 70 18-43-84-87-50 9 64 90 75 26-35-80-89-5715 kz1 kz14 kz2 kz13 kz3 kz12 kzkozToggleFlop1 =Add0 =Sub) 15 0 ( > KYADDSUBX64 57 -18-80 -84-26 50 90 64-9-75-87-35 43 89 70ADDSUBX64 43 50-90 35 57 89 26-64-87 18 70 84 9 75-805 kz10 kzADDSUBX64 26-75 70 35 90 18 80 64 43 89 9 84 57 50 876 kz9 kzADDSUBX64 9-89-26 84 43-75-57 64-70-50-80 35 87-18-907 kz8 kz4 kz11 kzHnh 4.17: S khi thc hin bin i DCT-2D 16x1672Tm tt qu trnh thc hin bin i DCT 2D 16x16 qua biu dng thut ton (Hnh 4.18)Khi DCT-2D 16x16 c vit bng VHDL (Hnh 4.19a) v c m t bng System generator (Hnh 4.19b).73NNChuyn d liu gc 16x16 u vo vo b m1-D 1X16 DCTCc h s DCT hng 1 vo b mHng cui cng1-D 1x16 DCTCc h s DCT ct 1 vo b mCt cui cngHng tip theoCt tip theoKt thcHnh 4.18: Biu dng thut ton 2-D DCT 16x16(a) (b)Hnh 4.19: Khi thc hin DCT-2D 16x16Cc chn tn hiu giao din ca khi:CLK: tn hiu xung nhp ca h thng.RST: tn hiu reset ca h thng, mc tch cc RST=1.Rdy_in: tn hiu iu khin bo c tn hiu video vo tch cc cc khi x l, mc tch cc rdy_in=1.Xin(7:0): L tn hiu data 8 bits c biu din di dng m b 2. Khi tn hiu rdy_in=1 th tn hiu xin(7:0) mi c x l.Rdy_out: tn hiu iu khin cho bit bt u xut hin phn t u tin h s DCT 2-D u ra. N bo cho khi sau l ang c tn hiu video tch cc. Tn hiu rdy_out tr so vi rdy_in l 154 chu k xung nhp. Mc tch cc u ra l rdy_out=1.Dct_2d_16x16(11:0): tn hiu data 12 bits c biu din di dng module (1 bit du v 11 bit d liu data). Tn hiu ny c a ra sau 154 chu k xung nhp74DCT-2D 16x16rdy_inxindct _2d_16x16rdy_out3.1.4. Xy dng khi lng t haTheo 3.1.3, Lng t ha thc cht l php chia tng ng gia cc gi tr u vo cho cc h s ca bng lng t v lm trn kt qu ca php chia . Trong ngn ng VHDL, vic thc hin php chia gia hai kiu d liu std_logic_vector vi nhau l khng th thc hin c. V vy, thay v thc hin php chia, ta thc hin php nhn gia gi tr u vo vi gi tr nghch o ca cc h s ca bng lng t.Cch biu din s nghch o ca mt s nguyn thnh kiu std_logic_vector nh sau:- Trc ht ta ly nghch o ca s nguyn . V d ly nghch o ca s 16 ta c s thc 0.0625.- Tip theo nhn s nghch o vi 2 sao cho kt qu bng 1 hoc gn vi gi tr 1 nht th dng li.0.0625 x 2 = 0.125 , bit nh phn l 0 (MSB)0.125 x 2 = 0.25 , bt nh phn l 00.25 x 2 = 0.5 , bit nh phn l 00.5 x 2 = 1.00 , bit nh phn l 1, dng li y.Kt qu l 0.0625(10)=0001(2) tng chnh xc ca php nhn vi s nghch o ta biu din cc h s ca ma trn lng t sau khi ly nghch o di dng s nh phn 10 bits. Khi 0.0625(10) = 0001000000(2).Vic lm trn kt qu ca php chia tng ng vi php dch tri kt qu ca php nhn i 10 bits.75ti sdnghai bnglngtthamkhotAnnexKtheoMc3.1.3 l Bng 3.2 cho thnh phn chi, v Bng 3.3 cho thnh phn mu.Thc hin biu din ma trn cc h s lng t nghch o ca Bng 3.2 v Bng 3.3 ta thu c hai Bng 4.1 v Bng 4.2 tng ng nh sau :Bng 4.1 : Ma trn cc gi tr nh phn nghch o ca ma trn lng t chi Y0001000000 0001011101 0001100110 0001000000 0000101010 0000011001 0000010100 00000100000001010101 0001010101 0001001001 0000110101 0000100111 0000010001 0000010001 00000100100001001001 0001001110 0001000000 0000101010 0000011001 0000010001 0000001110 00000100100001001001 0000111100 0000101110 0000100011 0000010100 0000001011 0000001100 00000100000000111000 0000101110 0000111011 0000111010 0000001111 0000001001 0000001001 00000011000000101010 0000011101 0000010010 0000010000 0000001100 0000001001 0000001000 00000010110000010100 0000010000 0000001101 0000001011 0000001001 0000001000 0000001000 00000010100000001110 0000001011 0000001010 0000001010 0000001001 0000001010 0000001001 0000001010Bng 4.2 : Ma trn cc gi tr nh phn nghch o ca ma trn lng t mu0000111100 0000111000 0000101010 0000010101 0000001010 0000001010 0000001010 00000010100000111000 0000110000 0000100111 0000001111 0000001010 0000001010 0000001010 00000010100000101010 0000100111 0000010010 0000001010 0000001010 0000001010 0000001010 00000010100000010101 0000001111 0000001010 0000001010 0000001010 0000001010 0000001010 00000010100000001010 0000001010 0000001010 0000001010 0000001010 0000001010 0000001010 00000010100000001010 0000001010 0000001010 0000001010 0000001010 0000001010 0000001010 00000010100000001010 0000001010 0000001010 0000001010 0000001010 0000001010 0000001010 00000010100000001010 0000001010 0000001010 0000001010 0000001010 0000001010 0000001010 000000101076Khi lng t ha c vit bng VHDL (Hnh 4.20a) v c m t bng System generator (Hnh 4.20b).

Quantizerdct _inrdy_inchro_inchro _outquant _outrdy_out(a) (b)Hnh 4.20: Khi thc hin thut ton lng t haCc chn tn hiu giao din ca khi:CLK: tn hiu xung nhp h thngRST: tn hiu reset ca h thng, mc tch cc l RST=1Rdy_in : tn hiu iu khin bo c tn hi video tch cc cc khi x l, mc tch cc rdy_in=1.Chro_in : bo hiu tn hiu vo b x l l tn hiu chi Y (chro_in=0) hay tn hiu mu CbCr (chro_in=1).Dct_in(11 :0) : l tn hiu data u vo 12 bits c biu din di dng s module (1 bit du v 11 bits gi tr). Khi tn hiu rdy_in=1 th tn hiu dct_in mi c x l.Rdy_out : tn hiu iu khin bo c tn hiu quant_out cho cc khi sau bt u x l.Chro_out : cho bit tn hiu a n khi sau x l l tn hiu chi hay tn hiu mu.77Quant_out(11:0) : tn hiu data 12 bits u ra b lng t ha, c biu din di dng module (1 bit du v 11 bits gi tr data).Nguyn l hot ng ca b lng t ha c th hin trn Hnh 4.21.REGISTERB nhn 12x10Data_in(11:0)CLKRSTRdy_inQuant_out(11:0)B iu khinChro_inData(7:0)Rdy_outChro_outMa tran luong tu choi YMa tran luong tu mau CbCrData(9:0)Data(9:0)Hnh 4.21 : S nguyn l hot ng ca b lng t haNu tn hiu rdy_in mc cao th c tn hiu tch cc ti cc chn tn hiu u vo : data_in v chro_in. Thanh ghi REGISTER s dch tng gi tr ti u vo data_in theo tng xung nhp CLK. B iu khin s da vo tn hiu iu khin chro_in la chn bng lng t chi Y nu chro_in=0, v chn bng lng t mu CbCr nu chro_in=1. Cc gi tr ma trn lng t chi c lu tr trong RAM1 sau a gi tr vo b nhn 12x10 theo tng xung nhp thc hin php nhn. y ta s dng b nhn khng ng b cho nn kt qu s c a ra ngay khi c tn hiu vo. Cc tn hiu iu khin ti u ra : rdy_out, chro_out cng c a ra ph thuc vo cc tn hiu u vo.784.1.5. Xy dng khi qut zigzagNh trnh by c s l thuyt ca thut ton qut zigzag trong Mc 3.1.4, chc nng ca khi ny l chuyn i mng 2 chiu thnh mng 1 chiu theo th t c bit trc nh Hnh 3.7. 64 h s DCT trong 1 block sau khi c lng t ha quant_out(11:0) s c qut zigzag theo th t zigzag bit trc (Hnh 3.7). Mun ghi cc gi tr vo tun t v c ra theo th t khc bit trc th nht thit phi s dng 2 b nh RAM(64x9) thc hin chc nng qut zigzag.Khi qut zigzag c vit bng m VHDL (Hnh 4.22a) v c m t bng System generator(Hnh 4.22b).

zigzag _scanrdy_inqdct _inchro_inchro_outzigzag _outrdy_out(a) (b)Hnh 4.22 : Khi thc hin qut zigzagCc chn tn hiu giao din ca khi :CLK : tn hiu xung nhp h thngRST : tn hiu reset ca h thng, mc tch cc RST=1Rdy_in : tn hiu iu khin thc hin bo c tn hiu video tch cc khi bt u thc hi x l, mc tch cc rdy_in=1.79Chro_in : cho bit tn hiu ang x l l tn hiu chi Y (chro_in=0) hay tn hiu mu CbCr (chro_in=1)Qdct_in(11:0) : l tn hiu data u vo 12 bits c biu din di dng s module (1 bit du v 11 bits gi tr). Khi tn hiu rdy_in=1 th qdct_in(11:0) mi c x l.Rdy_out : tn hiu iu khin bo cho bit u ra khi c tn hiu tch cc. Tn hiu ny tr so vi rdy_in l 64 chu k xung nhp.Chro_out : tn hiu bo cho bit u ra khi l tn hiu chi Y hay tn hiu mu CrCb. Tn hiu ny tr so vi tn hiu chro_in l 64 chu k xung nhp.Zigziag_out(11:0) : tnhiudata12bitsuracbiudindi dng module (1 bit du v 11 bits gi tr data).Nguyn l hot ng ca khi (Hnh 4.23) :RAM 64x9 RAM 64x9ControllerRdy_outChro_outCLKRSTRdy_inChro_inQdct _in(11:0)Zigzag_out(11:0)addrsel_ramen_ramHnh 4.23 : S nguyn l hot ng ca khi qut zigzag80Khi c tn hiurdy_in=1, th RAM1 s ghi ln lt cc gi tr qdct_in(11:0) vo, trong khi RAM2 cha c d liu ra cng nh ghi d liu vo (xem xt trong 64 chu k xung nhp u tin), lc ny b iu khin Controller thit lp tn hiu sel_ram=0. Trong 64 chu k tip theo, b controller thit lp en_ram=1 (mc tch cc), sel_ram=1. iu ny c ngha l RAM1 ang c d liu ra theo a ch addr m controller gi ti, v RAM2 ang ghi d liu vo. Trong64chukktip, controller araen_ram=1, sel_ram=0, tcl RAM1 ang ghi d liu vo v RAM2 ang c d liu ra. Qa trnh c tip tc nh vy cho ti khi kt thc d liu a vo. Cc tn hiu iu khin ti u ra rdy_out v chro_out l tn hiu tr ca cc tn hiu u vo rdy_in v chro_in vi tr l 64 chu k xung nhp.4.1.6. Xy dng khi m ha EntropyM ha Entropy gm c hai khu l m ha bc chy (RLE: Run Length Encoding) v m ha Huffman (Hnh 4.24).Hnh 4.24: M ha Entropy4.1.6.1. Khi m ha bc chy RLETrong chun nn JPEG, cc h s DCT sau khi c lng t ha thng c rt nhiu h s c gi tr bng 0. V vy s dng m ha RLE s tng t s nn ln ng k. Theo 3.1.5 th thc cht m ha RLE l thay th cc h s c gi tr bng 0 bng s lng cc ch s 0 xut hin. Kt qu sau khi m ha RLE l 81M ha EntropyRLEHuffman codingZigzag_outCoded outputcp: (chiu di chui 0, gi tr). Trong JPEG khng cho php bc chy ca s 0 vt qu 16, do c 16 s 0 s c m ha thnh (15,0). EOB l k hiu ch tt c cc h s cn li trong ma trn bng 0, c m ha bng 1010 (i vi block chi Y). i vi block mu CbCr th tn hiu EOB c thay bng m 00.Khi m ha RLE ny khng c tr v thnh phn u tin ca 1 block bao gi cng l h s DC c gi tr khc 0 nn kt qu c a ra ngay. Khi m ha bc chy RLE c vit bng m VHDL (Hnh 4.25a) v c m t bng System generator (Hnh 4.25b).RLErdy _inchro _inzigzag _indc _outrl_outrdy _outchro _outeob

(a) (b)Hnh 4.25: Khi thc hin m ha bc chy RLECc chn tn hiu giao din ca khi:CLK: tn hiu xung nhp h thng.RST: tn hiu reset ca h thng, mc tch cc RST=1.Rdy_in: tn hiu iu khin bo c tn hiu video tch cc cc khi x l, mc tch cc rdy_in=1.Chro_in: bo hiu tn hiu ang x l l tn hiu chi Y(chro_in=0) hay tn hiu mu CbCr (chro_in=1)82Zigzag_in(11:0): l tn hiu data u vo 12 bits, c biu din di dng s module (1 bit du v 11 bits gi tr). Khi tn hiu rdy_in=1 th tn hiu zigzag_in mi c x l.Rdy_out: tn hiu iu khin bo cho khi sau l ang c tn hiu video tch ccDc_out(11:0): tn hiu data u ra 12 bits c biu din di dng module (1 bit du v 11 bits gi tr data). Tn hiu ny ch th gi tr ca tn hiu video.Rl_out(17:0): tn hiu ch th chiu di chui 0.Chro_out: tn hiu bo cho bit u ra khi l tn hiu chi Y hay tn hiu mu CrCb4.1.6.2. Khi m ha HuffmanT c s l thuyt ca thut ton m ha Huffman (Mc 3.1.5.2), tin hnh thc hin vit chng trnh da theo cc bi vit ng dng t cc tc gi ca Xilinx. Khi m ha Huffman c vit bng m VHDL (Hnh 4.26a) v c m t bng System generator (Hnh 4.26b). Huffman encodingrdy_inrl_indc_inchro_ineobhuffman _outrdy_out(a) (b)Hnh 4.26: Khi thc hin m ha Huffman83Cc chn tn hiu giao din ca khi:Dc_in(11:0): D liu u vo b Hufman, c biu din theo dng module 12 bits, trong bt th 12 l bt du v 11 bits cn li biu din gi tr.Rl_in(17:0): ch th chiu di chui 0 (bc chy) ca tn hiu u vo.Chro_in: Chro_in: bo hiu tn hiu ang x l l tn hiu chi Y(chro_in=0) hay tn hiu mu CbCr (chro_in=1)CLK: tn hiu xung nhp h thng.RST: tn hiu reset ca h thng, mc tch cc RST=1.Rdy_in: tn hiu iu khin bo c tn hiu video tch cc cc khi x l, mc tch cc rdy_in=1.Eob: tn hiu cho bit block ang x l c tt c cc h s bng 0 hay khng (1 cho bit cc h s trong block u bng 0).Rdy_out: tn hiu iu khin bo cho bit bt u c tn hiu ti u ra b m ha.Huffman_out(15:0): d liu u ra b m ha Huffman.4.1.7. Tng hp khi nn nh JPEGT c s l thuyt ca thut ton nn JPEG (Mc 3.1), tin hnh phn tch thut ton v tng hp t cc khi c thit k v xy dng trn, ta thu c khi nn nh JPEG (c vit bng m VHDL) (Hnh 4.27). Khi nn nh JPEG bao gm cc khi nh: khi bin i khng gian mu RGB thnh YCrCb (color_conv_cw), khi ly mu li tc mu mu (color_resampler444to420), hai khi bin i DCT 2D cho block nh 8x8 cho tn hiu chi v tn hiu mu. 8485Hai khi lng t ha (quant) thc hin lng t ha bin i vi hai bng lng t cho trc cho tn hiu DCT chi v tn hiu DCT mu, hai khi qut zigzag (zigzag_scan) thc hin chuyn chui 2 chiu thnh 1 chiu cho m ha entropy. Khi m ha entropy gm c 2 khi m ha bc chy (rle_en) v 2 khi m ha Huffman(Huffman_en). Cui cng cc tn hiu chi v mu sau khi m ha c ghp li ti b ghp 2 u vo 16 bits(mux32).Cc chn tn hiu giao din ca khi: CLK_in: tn hiu xung nhp u vo cho c h thngRST_in: tn hiu reset cho h thng.Ce_in: tn hiu khch hot h thng.Red_in(7:0): tn hiu mu R 8 bits c ly sau iu ch gamma (camera) a vo khi JPEG.Green_in(7:0): tn hiu G 8 bits c ly sau iu ch gamma (camera) a vo khi JPEG.Blue_in(7:0): tn hiu B 8 bits c ly sau iu ch gamma (camera) a vo khi JPEG.Jpeg_out: tn hiu d liu nh nn u ra, c biu din di dng module 16 bits, trong 1 bit du v 15 bits data.Jpeg_rdy_out: tn hiu bo tch cc u ra b nn.4.2. Cc thut ton WatermarkingThut ton watermarking c kho st trong c hai min l trong min nn JPEG v trong min cha nn JPEG.4.2.1. Xy dng khi thut ton Watermarking-JPEG trong min nn86T c s l