时空二值编码结构光三维成像中的亚像素匹配方法

Subpixel Matching of Three-Dimansional Imaging System Using Binary Spatiotemporal Encoded Illumination

在时空二值编码结构光三维成像系统中,一个投影仪像素通常与摄像机图像坐标系的多个像素对应。为提高系统的测量精度及数据密度,提出了一种适用于时空二值编码结构光三维成像系统的摄像机与投影仪图像亚像素匹配方法。根据测量系统的二维传递函数的低通滤波特性和时空二值编码方案,对摄像机采集的图像采用时间正弦拟合的方法求解每个像素处的相位。由于该相位与投影仪图像坐标成正比关系,所以可以实现摄像机与投影仪图像的亚像素匹配。实验结果表明该方法可将系统的测量精度提高1个数量级。在相同实验条件下的测量精度与相位测量轮廓术的相当。

Severval camera pixels are usually corresponding to one projector pixel in three-dimensional（3D） imaging system using binary spatiotemporal encoded illumination.A novel method is proposed for subpixel image matching of camera and projector to increase the measurement precision and data density.The phase distribution of image captured by camera is obtained with sinusoid fitting on temporal direction,according to the binary spatiotemporal encoding strategy and the low pass filter characteristic of two-dimensional transfer function of measurement system.Because of the direct ratio of the phase distribution and projector pixel the corresponding point pairs between the image of projector and camera can be identified through the phase distribution with subpixel accuracy.The experimental results show that the measurement precision of the 3D imaging system is increased about one order of magnitude by using proposed method,and its measurement precision is similar with that of the phase measurement profilometry under the same experimental condition.