IEEE Transactions on image processing

Vol. 20, No.10, October 2011

by Andrea Giachetti and Nicola AsuniSpeaker : 吳惠仙首頁須把論文出處，含發表期刊，發

表年與作者清楚標示出來

Outline Introduction

What’s the problem about image upscaling?

Related Works Polynomial interpolation Statistical Methods Edge-directed interpolation

Proposed Scheme ICBI(Iterative Curvature Based Interpolation) CUDA

Experiment Results Objective test and Subjective test

Conclusions

論文報告大綱需有這幾個項目

What’s the problem about image upscaling?

Sometimes we need to obtain a digital image to be represented on a large bitmap from original data, it should look like it had acquired with a sensor having the resolution of the upscaled image or at least, present a “natural” texture.

Introduction

一開始先把論文要解決的問題說清楚，盡可能用圖來解說

What’s the problem about image upscaling?

But we have a problem is, how to insert these unknown values to the high resolution image?

The solution to the problem is often referred to also as “single image super-resolution” that allows to obtain an High Resolution image from its Low Resolution counterpart.

Introduction

緊接著請把這個題目的挑戰性做個說明，盡可能用圖來解說

Polynomial interpolation

The simplest interpolation based on linear filtering.

Methods like: Nearest Neighbor interpolation, Bilinear, Bicubic…

adv. : computationally efficient(Bicubic is not.)dis. : blur and jagged contours

Related works 在 Related Works簡要介紹解決此問題的相關研究，把其概念想法，優點與缺點說清楚

Statistical Methods Some authors have tried to exploit pixel or

texture statistics or database of example images to obtain good high resolution images.

Methods like : Example-based learning single-image for super-resolution[2008]

adv. : variety of natural textures and scales makes.dis. : need a sufficiently representative set of examples.

Related works

讓投影片有高可讀性， 盡可能用完整英文句子。重點可以特別標示出來。

Edge-directed Interpolation These methods try to improve the accuracy of the

interpolation characterizing the edge features in a larger region. They aims at interpolating along edges rather than across them to prevent blurring.

Methods like: NEDI(New Edge-Directed Interpolation)[2001]iNEDI(improved NEDI)[2008]

adv. : have good results for natural images.dis.: NEDI and iNEDI have high computationally.

Related works

介紹相關研究時，盡可能按照其發表時間依序介紹

Edge-directed Interpolation NEDI

estimates local covariance coefficients from a low-resolution image

Use these covariance estimates to adapt the interpolation at a higher resolution based on the geometric duality between the low-resolution covariance and the high-resolution covariance.

Note:NEDI and iNEDI still create evident artifacts due to the effect of edge discontinuities.

Related works

vs.

藉由相關研究的探討，來點出所提演算法想要真正解決的問題點

two-step hole filling from NEDI

in the first one, pixels indexed (Fig1.A) are computed as a weighted average of the four diagonal neighbors .

in the second the remaining holes(Fig1.B) are filled with the same rule(in horizontal and vertical directions).

Proposed Scheme-ICBI

介紹所提演算法時，應先描述其主要想法，盡可能用圖來解說

FBCI(Fast Curvature-Based Interpolation)

average of the two neighbors in the direction of lowest second order derivative using 8 valued neighboring pixels, then assigning to the point(2i+1, 2j+1) in the direction where the derivative is lower.

Proposed Scheme-ICBI

Energy Function Define an energy component at each new pixel

location that is locally minimized when the second order derivative are constant.

Then modified the interpolated pixel values in an iterative greedy procedure trying to minimize the global energy.

Proposed Scheme-ICBI

U(2i+1,2j+1) : final value Uc(2i+1,2j+1) : curvature smoothing Ue(2i+1,2j+1) : curvature enhancement Ui(2i+1,2j+1) : isophote smoothing a, b, c, T : chosen by trial and error in order to maximize the perceived

and measured image quality.

數學式要簡單扼要，符號要定義清楚，數學式的物理意義要解說清楚

Energy FunctionProposed Scheme-ICBI

Contributions A review of constant covariance constraint used in the NEDI

method with the proof of the relationship of that constraint with the second order derivatives smoothness used in our algorithm.

ICBI based on the iterative smoothing of second order derivatives. The algorithm is initialized using a simple filling rule based on second order derivatives(FCBI) that can be considered an edge directed interpolation algorithm too.

ICBI method demonstrated to be an improvement over previous ones, providing a reasonable reconstruction of the missing information and requiring considerably less computational power than other methods achieving good scores.

A GPU implementation of the ICBI method able to enlarge images at interactive frame rates.

..

實驗結果前可以先總結一下論文的主要貢獻

Objective TestExperiment Results

可以把實驗結果中要注意的地方清楚標示出來

Objective Test Dell XPS M1210 laptop with Intel Core2 Duo

T7200 2.0 GHz CPU. PSNR

Computation Times

Experiment Results

把實驗條件與目的，評量結果的量化指標等說明清楚

Subjective Test There are12 people to compare images, in order to

select the best average “perceived quality”.

Experiment Results

CUDA implementation for real-time

GPUCard : nVidia GeForce GTX280 Language : Matlab and C 4x enlargement of 128x128 images in 16.2ms on

average, corresponding to a ideal frame rate of 62 frames per second.

 2x enlargement of 256x256 images in 12.3ms on average.

Experiment Results

最好讓大家可以由所提演算法的主要想法，就能理解推論實驗結果的正確必然性

Conclusion ICBI based on a greedy minimization of an energy

function defined at the interpolated pixel locations. ICBI is not computationally expensive like

example-based methods or NEDI and is easily parallelizable.

Noise image?

Conclusion

最後為論文做個總結，簡述其所解決的問題與主要貢獻。最好能提一下所提方法的限制與可能的問題