一种投影显示图像颜色失真校正方法
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摘要
颜色校正是提高投影显示图像视觉效果及内容感知理解程度的重要环节,针对此,提出了一种基于颜色空间变换和亮度响应函数(ITF)的颜色校正方法。设计一幅16×16的灰度渐变棋盘格作为标定图像,进行采样;利用测光表测量环境光,以调整相机拍摄参数;根据投影仪-相机系统映射关系矩阵,求解匹配采样点对;建立亮度响应曲线的经验参数模型,利用最小二乘法估计曲线参数;依据亮度响应曲线的反函数建立颜色查找表,从而实现投影显示图像的颜色失真校正。在LCD投影仪上进行了该算法的可行性和效果测试,实验结果表明:该算法校正后的投影画面质量较好,且实现简单。
Color correction is a key step for improving the visual effect of the projector display image and the understanding degree of the content,and a new correction algorithm is proposed based on color space conversion and Intensity Transfer Function(ITF).This paper designs a 16×16 gray checkerboard as calibration image for sample;according to the mapping matrix of the projector-camera system,this paper solves the matching sampling points;it selects an empirical parametric curve to match the ITF,and estimates the parameters by the least squares method based on the sampling points;it calculates a color lookup table on the bases of the inverse function of the ITF,in order to achieve the color correction of the projection display image.In order to examine the feasibility and effectiveness,the proposed algorithm is implemented on an LCD projector.The test results show that this algorithm can achieve better display effect after correction,and it is simple and easy to use.
Color correction is a key step for improving the visual effect of the projector display image and the understanding degree of the content,and a new correction algorithm is proposed based on color space conversion and Intensity Transfer Function(ITF).This paper designs a 16×16 gray checkerboard as calibration image for sample;according to the mapping matrix of the projector-camera system,this paper solves the matching sampling points;it selects an empirical parametric curve to match the ITF,and estimates the parameters by the least squares method based on the sampling points;it calculates a color lookup table on the bases of the inverse function of the ITF,in order to achieve the color correction of the projection display image.In order to examine the feasibility and effectiveness,the proposed algorithm is implemented on an LCD projector.The test results show that this algorithm can achieve better display effect after correction,and it is simple and easy to use.
引文
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[19]王修晖,华炜,鲍虎军.多投影显示墙的全局颜色校正[J].计算机辅助设计与图形学学报,2007,119(11):96-101.
[20]Chen X,Yang X,Xiao S,et al.Color mixing property of a projector-camera system[C]//IEEE CVPR Workshop on Projector Camera Systems,2008:155-156.
[2]Hereld M,Judson I R,Stevens R L.Introduction to build-ing projection-based tiled display systems[J].IEEE Com-puter Graphics and Applications,2000,20(4):22-28.
[3]Majumder A,Herman Z H,GregWelch T.Achieving color uniformity across multi-projector displays[C]//Proceedings of IEEE Visualization,2000:117-124.
[4]Majumder A,Stevens R.LAM:Luminance Attenuation Map for photometric uniformity in projection based displays[C]//Proceedings of the ACM Symposium on Virtual Reality Software and Technology,2002:147-154.
[5]Majumder A,Stevens R.Color non-uniformity in projec-tion-based displays:analysis and solutions[J].IEEE Trans-actions on Visualization and Computer Graphics,2003,10(2):177-188.
[6]Majumder A,Stevens R.Perceptual photometric seamless-ness in tiled projection-based displays[J].ACM Transac-tions on Graphics,2005,24(1):118-139.
[7]Yang R,Majumder A,Brown M.Camera based calibration techniques for seamless muIti-projector displays[J].IEEE Trans on Visualization and Computer Graphics,2005,11(2):193-206.
[8]Sajadi B,Lazarov M,Majumder A,et al.Color seamless-ness in multi-projector displays using constrained gamut morphing[J].IEEE Trans on Vis Comput GraPh,2009,15(6):1317-1342.
[9]Harville M,Culbertson B,Sobel I,et al.Practical methods for geometric and photometric correction of tiled projec-tor displays on curved surfaces[C]//CVPR Workshop on Projector Camera Systems,2006:52-59.
[10]Stone M C.Color and brightness appearance issues for tiled displays[J].IEEE Computer Graphics and Applica-tions,2001,21(5):58-66.
[11]Wallace G,Chen H,Li K.Color gamut matching for tiled display walls[C]//Eurographics Workshop on Virtual En-vironments,2003:293-302.
[12]Raskar R,Beardsley P.A self-correcting projector[C]//IEEE Computer Vision and Pattern Recognition(CVPR),2001:626-631.
[13]Raskar R,Baar J,Beardsley P,et al.iLamps:geometrical-ly aware and self-configuring projectors[C]//ACM SIG-GRAPH,2003:809-818.
[14]Jin M,Zhang H,Yang X,et al.A real-time ProCam sys-tem for interaction with Chinese ink-and-wash car-toons[C]//IEEE CVPR Workshop on Projector Camera Systems,2007:1-2.
[15]Barnum P,Narasimhan S,Kanade T.A projector-camera system for creating a display with water drops[C]//IEEE Computer Vision and Pattern Recognition(CVPR),2009:17-23.
[16]王峰,李华,庄磊,等.投影显示系统屏幕亮度均匀性及校正方法[J].电子测量技术,2003(5):33-34.
[17]郑臻荣,顾培夫.液晶投影显示的色纯度和色均匀性[J].光电工程,2002,29(5):30-32.
[18]张懿.大屏幕投影拼接系统的色均匀矫正[D].杭州:浙江大学,2006:27-42.
[19]王修晖,华炜,鲍虎军.多投影显示墙的全局颜色校正[J].计算机辅助设计与图形学学报,2007,119(11):96-101.
[20]Chen X,Yang X,Xiao S,et al.Color mixing property of a projector-camera system[C]//IEEE CVPR Workshop on Projector Camera Systems,2008:155-156.