藉由降低像素間偶合以及減少校準圖案數量之色彩補償增強與加速

Enhancement and Speedup of Photometric Compensation for Projectors by Inter-Pixel Decoupling and Calibration Pattern Reduction

劉人碩(Jen-Shuo Liu)

指導教授 ： 陳宏銘

國立臺灣大學/電機資訊學院/電信工程學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201610297

摘要

當投攝影機要在非白色表面上保持影像的色彩外觀時，由投影表面顏色所造成的色彩扭曲必須適當地被補償。此類色彩補償的表現倚賴準確的投影機非線性估計。在本論文中，我們藉由考量像素間的耦合關係來改善投影機非線性估計的準確度。此外，為了因應由於投影機移動導致的投影區域改變，我們將校準用的圖片數量由六張減到一張，正在被投影的影像也可作為此張校準影像。這種方法大大地改良為了維持多媒體展演連續性而需要被及時處理的動態反射率校準之運算效率。主觀和客觀的實驗結果顯示我們的方法可以有效且快速地補償色彩扭曲。

關鍵字

投攝影機系統 ； 色彩補償 ； 伽馬非線性估計 ； 光學校準 ； 多媒體展演

並列摘要

For a procam to preserve the color appearance of an image projected on a color surface, the photometric distortion introduced by the color surface has to be properly compensated. The performance of such photometric compensation relies on an accurate estimation of the projector nonlinearity. In this thesis, we improve the accuracy of projector nonlinearity estimation by taking inter-pixel coupling into consideration. In addition, to respond quickly to the change of projection area due to projector movement, we reduce the number of calibration patterns from six to one and use the projected image as the calibration pattern. This greatly improves the computational efficiency of dynamic reflectance calibration that needs to be performed on the fly during a multimedia presentation without breaking its continuity. Both objective and subjective results are provided to illustrate the effectiveness of the proposed method for color compensation on the fly.

並列關鍵字

procam ； photometric compensation ； gamma nonlinearity estimation ； photometric calibration ； multimedia presentation.

參考文獻

[2] M. D. Grossberg, H. Peri, S. K. Nayar, and P. N. Belhumeur, “Making one object look like another: controlling appearance using a projector-camera system,” in Proc. CVPR, pp. 452–459, 2004.

[3] K. Fujii, M.D. Grossberg, and S. K. Nayar. “A Projector-Camera System with Real-Time Photometric Adaptation for Dynamic Environments,” in Proc. IEEE Conf. on Computer Vision and Pattern Recognition, pp. 814–821, 2005.

[4] O. Bimber, A. Emmerling, and T. Klemmer, “Embedded entertainment with smart projectors,” IEEE Computer, vol. 38, no. 1, pp. 48–55, 2005.

[5] G. Wetzstein and O. Bimber, “Radiometric compensation through inverse light transport,” in Proc. Pacific Conf. Comput. Graph. And Appl., pp. 391–399, 2007.

[6] A. Grundhofer and O. Bimber, “Real-Time Adaptive Radiometric Compensation,” IEEE Trans. Vis. Comput. Graphics, vol. 14, no. 1, pp. 97–108, 2008