三维测量结构光一维编码投影机的设计

Unidimensional Scalable Method for Structured Light Projection of 3D Measurement

以商用投影机作为光源的结构光三维测量系统中,所有的编码图案都是以二维矩阵的形式由计算机传送给投影机,再由投影机以二维图像的形式投射至被扫描对象。如果编码是条纹式图案,没有考虑到条纹式结构光编码中灰度信息在同一行或者同一列保持不变的特点。因此,根据条纹式编码的单方向变化特性,提出一种将一维编码序列自动扩展成二维编码图像的结构光扫描专用的投影机设计方案,利用包含所有灰度信息的一维编码序列和设计好的扩展电路,对结构光编码图像进行像素扩展,以提高结构光三维成像的投影效率。实验结果表明,与液晶显示投影机相比,投射相同样式的结构光编码图像时,该投影设计的速度可以提高71.8%,且能够保持相位精度差的数量级在10-3,有效地提高了结构光三维测量中结构光编码图像的投影重建效率。

In the structured light 3D measurement system using the commercial projector as the source, all the encoding patterns are projected with the two-dimensional matrix form. The computer transmits the patterns to the projector, and the patterns are projected onto the scanned object by two-dimensional images. If the code is a striped pattern, the characteristics of stripe structured light coding that the gray information remains unchanged in the same line or in the same column are not considered. Therefore, according to the unidirectional characteristic of the fringe encoding, we present a design scheme of a special structure projector, which can automatically extend one- dimensional gray sequence into encoded structured light. One-dimensional coding sequence with all gray information and a designed pixel-extended circuit are used to expand the pixel of structured light coded image, in order to improve the projection efficiency of structured light 3D imaging. The experimental results show that the speed of projection is improved by about 71.8% compared with liquid crystal display projection method, and the order of magnitude of phase accuracy difference is 10^-3. The projection efficiency of dual encoded structured-light images in 3D measurement is effectively improved.