编码光系统的颜色耦合与颜色失衡校正

Calibration of color coupling and color unbalance in coded structured light system

为了减小编码光系统中的颜色耦合与颜色失衡的干扰,提高形状与颜色重建的准确度,建立了彩色编码光系统,并对其所采用的编解码方法、颜色重建的两个相关环节及颜色校正方法进行了研究。首先,给出了系统的彩色梯形相移强度比编解码法,分析了编解码过程中存在的RGB基色相互耦合现象,设计了应用Caspi模型硬件标定的颜色耦合校正方案;然后,给出了系统的逐点颜色重建法,分析了颜色重建过程中由表面曲率导致的颜色失衡现象,设计了利用表面几何信息校正颜色失衡的方案。实验结果表明:校正后单一绿色图像中的红色分量值约为校正前的1/10;单色表面色差约为0.1,趋近于人眼颜色分辨率,远低于校正前的0.4;重建的单色复杂被测表面颜色均匀、视觉效果良好,符合实际情况。提出的方法符合编码光系统抗干扰能力强的要求,有助于提高形状与颜色重建的准确度。

To reduce the interference of color coupling and color unbalance and to increase the reconstruction accuracy of shape and color in a coded structured light system,a color coded structured light system was established and two color-related sections（coding principle and color reconstruction） and their color calibration methods were investigated.First,based on the coding principle by color trapezoidal phase-shifting intensity ratio,the mutual coupling phenomenon between RGB primary colors in coding process was analyzed,and color coupling calibration scheme by Caspi model and hardware calibration was designed.Then,based on point-bypoint color reconstruction method,the unbalance phenomenon caused by surface curvature in color reconstruction process was analyzed,and color unbalance calibration scheme using surface geometry information was designed.Calibration experimental results indicate that the red component in pure green after calibration is about 1 /10 of that before calibration;and calibrated chromatic aberration of unicolor surface is about 0.1,which approaches to the visual resolving power and is significantly less than that before calibration（0.4）.Moreover,the reconstructed unicolor complex surface has uniform color and good visual effect and is accorded with measured surface.It can satisfy the system requirements of strong anti-interference,and is conduced to the reconstruction accuracy of shape and color.