Банки фильтров, шумоподавление

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23.10.2009. , . lukin@graphics.cs.msu.ru. . , STFT mp3 - PowerPoint PPT Presentation

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  • , 23.10.2009 lukin@graphics.cs.msu.ru

  • , STFT mp3 STFT , -

  • 1

  • , STFT , Short Time Fourier Transform (STFT)

  • , STFT- , STFT ( , , DFT ) : 6 ms12 ms24 ms48 ms96 ms

  • , : -

    : ,

  • : , STFT: STFT (Hann), 75%: DFT , (OLA):

  • ?

  • (masker) (maskee) ( )

  • ,

  • mp3 mp3-x[n]FFTQHuffman mp3

  • -Pre-echo (pre-ringing)

  • -

  • ,.. ( , )

  • , (energy compaction) ( , ) ( )

  • STFT STFTSpectral Subtraction,Short-Time Spectral Attenuation

  • ( ) (, ) : , STFT

  • (gate) , ( )

  • (attack/release time) : G , W , X .

  • :

  • (musical noise)

  • : ( ) G(f, t) ( ) ( ) G(f, t) / .

  • - ( ) 50

  • a,b(t) ( ) (t) ( )

    /

  • (t):

    ,

    (vanishing moments)

  • MeyerMortletMexican hat

  • - (CWT) f(t) a,b(t)

  • - (DWT) 2

    - (-),

  • - x[n] :

    , x[n] :

    :

  • 2 :

    , :( )()()

  • -

    (PR): . , .

  • - - -

    4 : () ()

  • - ?

  • 2

  • Salt and pepper , .// . . + Salt and pepperAWGN

  • Bilateral filterNon-Local MeansWavelet thresholdingDCT, PCA, ICA BM3D Salt and pepperAWGN

  • ,

  • Bilateral filter Bilateral filter

  • Bilateral filterBilateral filter: ( )

  • Non-Local Means Non-local means (NL-means) , (xi,j) xi,j

  • , bilateral filterNon-Local Means Buades et al 2005 q1 q2, q3+

  • Non-Local Means :

    : MMX/SSE , : +

  • Non-Local Means

    ( -)

    Y- YCrCb (YUV)

  • DWT - (thresholding, shrinkage) DWT+

  • : WAV BMP BMP (brush tool) : BMP WAV

    ? 256 ?

    : Photosounder