色調重現是藉由調整或映射高動態範圍影像，保存原始所看到影像的亮度以及更好的對比度，以獲得真實影像的色調呈現。本論文提出一個影像色調調整的方法，並且整合到我們所開發的穩健的彩色影像處理流程中。藉由影像的巨集邊緣資訊，將巨集邊緣統計分佈圖等化重新分佈，等化分佈的過程中尋求每張圖的色調曲線特性。經由實驗證明，我們提出的色調重現演算法能適應各種場景及環境光源，改善影像的對比及色彩的鮮明度。
除了在PC模擬之外，我們也將演算法移植到嵌入式系統發展版上。針對系統板的特性及加速執行運算速度，改變變數的宣告型態成為整數以及利用查表法技巧。實驗結果證明提出的演算法能適應於一般的嵌入式系統中，並且執行消耗的功率低於個人電腦執行的消耗功率。

Tone reproduction attempts to scale or map high dynamic range image data such that the resulting image has preserved the visual brightness and better contrast impression of the original scenes. In this paper, we propose a systematic approach to tone reproduction by histogram equalization of macro edges. The proposed approach has been integrated with a robust image processing pipeline, and the experimental results show that the proposed algorithm is very stable for accommodating diverse illuminants and scenes.
In addition to running simulation on a computer, we also have ported the algorithm to an embedded system development kit. Several modifications are implemented such as changing the variables to integer type, and speeding up some time consuming operations by using lookup tables (LUTs.) The experimental results show that the proposed algorithm can be realized on a typical embedded system whose computation power is typically lower than a personal computer.

[1] Hsien-Che Lee,“Introduction to color imaging science,”Cambridge University Press, 2005.
[2] Wen-Chung Kao, Chih-Chung Kao, Shou-Hung Chen, Yen-Wei Hung. “The embedded software architecture for real-time video and audio recording,” in Proc. CVGIP 05, Taiwan, ROC, 2005, pp. 1462-1467.
[3] Wen-Chung Kao, Sheng-Hong Wang, Lien-Yang Chen, and Sheng-Yuan Lin, “Design Considerations of Color Image Processing Pipeline for Digital Cameras,” IEEE Trans. Consumer Electronics, vol. 53, no. 4, Nov. 2006.
[4] J.A. Ferwerda, S. Pattanaik, P. Shirley, and D.P. Greenberg, “A model of visual adaptation for realistic image synthesis,”in Proc. SIGGRAPH '96 Conf. Proc., pp. 249-258, Aug. 1996.
[5] C. Connolly and T. Fliess, “A study of efficiency and accuracy in the transformation from RGB to CIELab color space,” IEEE Trans. Image Processing, vol. 6, pp. 1046–1048, July 1997.
[6] G. Ward, H. Rushmeier, and C. Piatko, “A visibility matching tone reproduction operator for high dynamic range scenes,”IEEE Trans. Visualization and computer Graphics, vol. 3, no. 4, pp. 291-306 Oct.-Dec. 1997.
[7] G. Qiu, and J. Duan, “An optimal tone reproduction curve operator for the display of high dynamic range images,”in Proc. IEEE Int. Symposium on Circuits and Systems (ISCAS), pp. 6276-6278, 2005.
[8] J. Duan , and G.. Qiu, “Fast tone mapping for high dynamic range images,” in Proc. IEEE Int. Conf. Pattern Recognition, vol. 2, pp. 847-850, 2004.
[9] D.J. Jobson, Z. Rahman, G. A. Woodell, “Properties and Performance of a Center/Surround Retinex,” IEEE Trans. Image Processing. vol. 6, no. 3, pp. 451 – 462, Mar. 1997.
[10] H. C. Lee, L. L. Barski, R. A. Senn, “Automatic tone scale adjustment using image activity measures,” United states Patent 5633511, Dec. 1995.
[11] J. S. Alkofer, “Tone Value Sample Selection in Digital Image Processing Method Employing Histogram Normalization,” United states Patent 4654722, May. 1985.
[12] R. C. Gonzalez and R. E. Woods, “Digital Image Processing, 2/E,” New Jersey, 2002.
[13] J. Tumblin and B. Wandell, “Tone reproduction for realistic images,” in Proc. IEEE Computer Graphics and Application, vol. 13, pp. 42-48, 1993.
[14] J. Tumblin, J.K. Hodgins, B. K. Guenter,“ Two Methods for Display of High Contrast Images,” ACM Tran. Graphics, vol. 18, no.1, Jan.1999.
[15] D.J. Jobson, Z. Rahman, G. A. Woodell, “A multiscale retinex for bridging the gap between color images and the human observation of scenes,” IEEE Trans. Image Processing. vol 6, no. 7, pp.965 – 976, Jul. 1997.
[16] E. H. Land and J. J. McCann, “Lightness and retinex theory,”Journal of the Optical Society of America, vol. 61, no. 1, pp. 1-11, 1971.
[17] J. Tumblin, G. Turk, LCIS：A boundary hierarchy for detail-preserving contrast reduction, in Proc. ACM SIGGAPH, pp.83-90, 1999.
[18] F. Durand, J. Dorsey,“ Fast bilateral filtering for the display of high-dynamic-range images,”ACM Tran. Graphics, vol. 21, no. 3, Jul. 2002.
[19] R. Fattal, D. Lischinski, and M. Werman, “Gradient domain high dynamic range compression,”ACM Trans. Graphics, vol. 21, no. 3, pp. 249-256, 2002.
[20] E. Reinhard, M. Stark, P. Shirley, and J. Ferwerda, “Photographic tone reproduction for digital images,”ACM Trans. Graphics, vol. 21, no. 3, pp. 267-276, 2002.
[21] F.J.J. Blommaert and J.B.Martens,“An object-oriented model for brightness perception, ”Spatial Vision, vol. 5, no. 1, pp.15-41, 1990.
[22] M. Ashikmin, “A tone mapping algorithm for high contrast images,”in Proc. 13th Eurographics Workshop Rendering, pp. 145-155, 2002.
[23] Wen-Chung Kao, Chih-Chung Kao, Shou-Hung Chen, Yen-Wei Hung. “The embedded software architecture for real-time video and audio recording,” in Proc. CVGIP 05, Taiwan, ROC, 2005, pp. 1462-1467.
[24] R.Ramanath, W.E Snyder, Y. Yoo, M.S. Drew, “Color image processing pipeline,” IEEE Trans. Signal Processing, vol. 22, no. 1, pp. 34 – 43, Jan. 2005.
[25] G.Sharma, H.J.Trussell,“Digital color imaging,” IEEE Trans. Image Processing, vol. 6, no. 7, pp. 901 – 932, Jul. 1997.
[26] Wen-Chung Kao, Sheng-Hong Wang, and Lien-Yang Chen, “Design consideration of color image processing pipeline for digital cameras,” IEEE Trans. Consumer Electronics, pp. 1144-1152, vol. 52, no. 4, Nov. 2006.
[27] Ping-Sing Tsai, Tinku Acharya and Ajay k. Ray, “Adaptive fuzzy color interpolation, ” Journal of Electronic Imaging, vol.11,no.3,July 2002.
[28] Wen-Chung Kao and Ying-Ju Chen, “Multistage bilateral noise filtering and edge detection for color image enhancement,” IEEE Trans. Consumer Electronics, pp. 1346-1350, vol. 51, no. 4, Nov. 2005.(SCI)
[29] K. Devlin,“A review of tone reproduction techniques,”Technical Report CSTR-02-005, Computer Science, Univ. of Bristol, 2002.
[30] Y. Monobe, H. Yamashita, T. Kurosawa, H. Kotera, “Dynamic range compression preserving local image contrast for digital video camera, ”IEEE Transactions on Consumer Electronics, Vol. 51, No. 1, Feb. 2005.
[31] E. Reinhard, and K. Devlin, “Dynamic range reduction inspired by photoreceptor physiology,”IEEE Trans. Visualization and Computer Graphics, vol. 11, no. 1, pp. 13-24, Jan.-Feb. 2005.
[32] S.S. Stevens and J.C. Stevens, “Brightness Function: Parametric effects of adaptation and contrast, ” J. Optical Soc. Am., vol. 53, no. 3, pp. 375-385, Mar. 1963.
[33] H. Zhang, and L. Lucchese, “A fast tone reproduction algorithm for high dynamic range image display,”IEEE 6th Workshop Multimedia on Signal Processing, pp. 275-278, 2004.
[34] A. Pardo , G. Sapiro“Visualization of High Dynamic Range Images”,IEEE Trans. Image Processing, vol. 12, no. 6, pp. 639-647, Jun., 2003.