彩色栅线动态三维测量中自适应相关匹配技术.docVIP

彩色栅线动态三维测量中自适应相关匹配技术 摘要 彩色栅线结构光三维测量可仅靠左右摄像机单幅图像完成像素级相位匹配，能够实现运动或者变形物体型面重构，但其测量精度有待进一步提高。在依据相位进行粗匹配的基础上，采用立体视觉数字相关技术在左右图像局部区域进行更细致的匹配。计算相关系数时，依据彩色栅线各个周期的色彩变化特性自适应调整不同颜色通道的权重，依据不同视点表面变形特性自适应调整左右相关窗口的尺寸。在极线方向上双线性插值进行亚象素匹配。实验结果证明自适应数字相关匹配技术在保证彩色栅线动态检测，分辨率高优点的同时，可有效改善测量精度至0.1mm，扩大测量适用范围。 关键词 结构光；动态三维测量；彩色栅线；自适应相关 Abstract 3D measurement of structured light of color grating can complete phase match of pixel between single image in left and right camera. It can realize the reconstruction of surface of objects that move or deform, but the accuracy of measurement needs to be improved. Based on the coarse match by phase, the more accurate match can be achieved in local region by digital correlation technique of stereo vision between left and right images. When calculating the correlation coefficient, the weights in different color channels are self-adapted according to the color variety feature in different period of color grating and the dimension of correlation window in left or right is self-adapted according to surface distortion feature from different view. The sub-pixel matching is achieved by bilinear interpolation along the direction of epipolar line. The experiment results prove that the matching technique of self-adaptation digital correlation can effectively improved the accuracy of measurement, expand the range of application while maintaining the advantages of dynamic measurement and high resolution. Keywords Structured light; Dynamic 3D measurement; Color grating; Self-adaptation correlation 前言 实体三维数据测量广泛应用于反求工程、产品质量检测和安全控制、物体识别、医学、影视娱乐等领域。相比其它三维测量技术，结构光三维测量将多个光平面同时投影到物体表面，一次完成可见视区的数据测量，具有非接触、效率高的优点。但由于需投影多幅编码图像[1,2]实现对不同光平面的编码，无法实现运动或者变形过程中的物体型面测量。近年来，对于动态三维测量的需求越来越多，比如像高速在线检测，零件加工变形分析，仿生学研究，人体检测等等。 国内外学者研究了多种结构光动态测量技术，常用的方法有借助系统组成构件之间特殊的空间几何约束关系[3，4]，利用信号调制融合多幅图像再解调[5]，或是用空域编码（伪随机序列编码，M-arrays编码等）取代典型的时域编码(相移法，二进制grey编码，n等级灰度编码等)[6]，但普遍存在测量精度低，测量数据稀疏，分辨率较低的缺点。也有的系统通过改善系统硬件性能，实现图像投影和拍摄的高速循环近似实现动态测量[7，8]，但要求物体变化相对缓慢且不可避免引入误差。本文采用一种彩色栅线空域编码策略，能够仅靠单次投影实现