研究生: |
陳昱宏 Yuh-Horng Chen |
---|---|
論文名稱: |
低複雜度多尺度梯度色彩插補演算法 Low-complexity Color Demosaicing Based on Multiscale Gradients |
指導教授: |
蘇崇彥
Su, Chung-Yen |
學位類別: |
碩士 Master |
系所名稱: |
電機工程學系 Department of Electrical Engineering |
論文出版年: | 2013 |
畢業學年度: | 102 |
語文別: | 中文 |
論文頁數: | 47 |
中文關鍵詞: | 解馬賽克 、色彩插補 、多尺度 、低複雜度 |
英文關鍵詞: | Demosaicing, color interpolation, multiscale, low-complexity |
論文種類: | 學術論文 |
相關次數: | 點閱:93 下載:3 |
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數位相機色彩插補是現在單一感測器數位相機之數位影像處理流程中最重要的部
份之一。近年來有許多基於分類器的色彩插補演算法被提出,傳統分類器色彩插補演
算法雖然再大多數的場合表現的極為優秀,但是存在著因分類錯誤造成嚴重錯色的問
題,因此我們試圖尋找不一樣的解決方案。近年來多尺度梯度演算法 (MSG)是最成功
的演算法之一,其擁有相當卓越的影像品質。多尺度梯度演算法使用權重混合的方式
來取代傳統分類器的作法,雖然這樣的作法可以大幅提高影像品質,但是相對的也大
大的提高計算複雜度。在本篇論文中我們仔細對多尺度梯度演算法進行了分析,研究
其權重設計,試圖尋找一種適合的替代設計,能在維持多尺度梯度演算法的影像品質
的情況下,降低其計算複雜度。本方法主要特點在於,合併了兩階段綠色平面插補的
權重設計。在初始插補綠色平面階段以及優化綠色平面階段能使用同一組權重矩陣設
計,有效的降低計算複雜度。實驗結果證明我們不僅在 PSNR 能取得與多尺度演算法
接近的表現,在較為接近人類視覺的 S-CIELab 也能有接近多尺度梯度演算法的表現。
在執行時間上,比起多尺度梯度演算法有明顯的改進,其方法一執行時間約減少
36.37%,而方法二則減少了 41.52%。
Demosaicing of the color filter array (CFA) is one of the most important parts of the
image processing pipeline for single sensor digital cameras. In the recent years, many
classifer-based demosaicing algorithms have been proposed and achieved excellent
performance in most situations. However, occasionally these algorithms generate results
with color artifacts due to wrong directional leads. Recently, the multiscale gradients (MSG)
algorithm was reported, which has the best reported image quality to this date. The MSG
algorithm used adaptive weight design to replace the conventional classifer-based design.
This design boosts the image quality; however, it made a trade-off with computational
complexity. In this thesis, modification and improvement to the MSG algorithm by low-
complexity multiscale gradients algorithm is attempted such that the computational
complexity is significantly reduced while maintaining the high image quality possessed by
the original MSG algorithm. Experimental results show that the proposed algorithm not
only maintains peak signal-to-noise ratio (PSNR) and S-CIELab. Two methods were
proposed in this thesis and the speeds compared to the original MSG algorithm were
increased by 36.37% and 41.52%, respectively, which is a significant improvement.
[1] B. E. Bayer, “Color imaging array,” U.S. Patent 3 971 065, Jul. 1976.
[2] R. Rajeev, E. Wesley, L. Griff, and S. Williams, “Demosaicking methods for Bayer
color arrays,” Journal of Electronic Imaging, vol. 11, no. 3, pp. 306-315, July 2002.
[3] C.-Y. Su and J.-K. Tseng, “Demosaicing using variable-size classifiers and
proportional weights,” in Proc. IEEE Int. Conf. Image Processing, pp. 493 - 496, Oct.
2009.
[4] Gnuplot website. [Online]. http://www.gnuplot.info/.
[5] I. Pekkucuksen and Y. Altunbasak, “Multiscale Gradients-Based Color Filter Array
Interpolation.” IEEE Trans. Image Processing, vol. 22, no. 1, pp. 157-165, Jan. 2013
[6] I. Pekkucuksen and Y. Altunbasak, “Edge strength filter based color filter array
interpolation,” IEEE Trans. Image Processing, vol. 21, no. 1, pp.393-397, Jan. 2012.
[7] K. H. Chung and Y. H. Chan, “Low-complexity color demosaicing algorithm based
on integrated gradients,” J. Electron. Imag., vol. 19, no. 2, pp. 021104-1–021104-15,
Jun. 2010.
[8] C.-Y. Su and W.-C. Kao, “Effective demosaicing using subband correlation,” IEEE
Trans. Consumer Electronics, Vol. 55, no. 1, pp. 199-204, Feb. 2009
[9] J. F. Hamilton Jr. and J. E. Adams, “Adaptive color plane interpolation in single color
electronic camera,” U. S. Patent 5 629 734, May 1997.
[10] Paliy, V. Katkovnik, R. Bilcu, S. Alenius, and K. Egiazarian, “Spatially adaptive
46color filter array interpolation for noiseless and noisy data,” Int. J. Imag. Syst. and
Technol., vol. 17, no. 3, pp. 105-122, 2007.
[11] S-CIELab Metric (2003). [Online]. Available at http://white.stanford.edu/~brian/
scielab/scielab.html.
[12] Kodak test images and the demosaicing code of successive approximation. [Online].
Available at http://www.csee.wvu.edu/~xinl/demo/demosaic.html.
[13] GNU GCC Website. [Online]. http://gcc.gnu.org/.
[14] CMake Website. [Online]. http://www.cmake.org/.
[15] OpenCV Website. [Online]. http://opencv.org/.
[16] C++ Reference.com website. [Online]. http://en.cppreference.com/w/cpp.
[17] cplusplus.com - The C++ Resource Network. [Online]. http://www.cplusplus.com/.
[18] GNU Octave Website. [Online]. http://www.gnu.org/software/octave/.
[19] Octave-Forge Website. [Online]. http://octave.sourceforge.net/.
[20] L. Zhang, X. Wu, A. Buades, and X. Li, “Color demosaicking by local directional
interpolation and non-local adaptive thresholding,” Journal of Electronic Imaging
20(2), 023016 (Apr-Jun 2011), DOI:10.1117/1.3600632.
[21] L. Zhang, “Mcmaster dataset.” [Online] http://www4.comp.polyu.edu.hk/~cslzhang/CDM_ Dataset.htm.