格雷码与六步相移编码融合的三维结构光学测量方法

Structured light technology based on gray code and six-step phase shift method

编码结构光技术是一种获取复杂目标三维结构的典型测量技术,其将编码后的结构光图案投射到待测物体表面进行调制、采集,并通过解码计算三维面形数据,可见编码方法是结构光三维测量技术的核心问题。然而,通用的格雷码编码方法和六步相移编码方法都存在一定缺陷,为此,以获取物体的高精度三维点云数据为目标,提出了一种融合格雷码与六步相移的结构光技术。首先,将格雷码结构光设计为7幅黑白相间的条纹周期图像,并通过投射角度解码操作将图像划分为多个区域;然后,设计六步相移结构光为6幅具有相位差的余弦周期图像,通过相位解包裹操作将每个子区域细分到单个像素单元;最后,融合以上两种编码结构光解码值,计算图像内每个空间点的绝对相位信息。仿真实验与实际测试实验显示,与传统六幅莫尔条纹结构光技术相比,融合结构光技术计算量较小,同时也克服了单独使用格雷码或相移技术所存在的问题,能够以较高精度获取物体目标的三维结构细节,为基于结构光的双目三维扫描系统提供一定理论依据。

Structured light technology is a typical method for capturing the three-dimensional point cloud data of realistic objects.Structured light images are projected on the surface of the object,which are modulated by the height of the object.Then,the modulated structured light is captured by the camera.Finally,the triangulation principle is used to calculate the three-dimensional surface shape data.To scan the high-precision three-dimensional point cloud of the object,this paper proposes a structured light technology based on Gray code and six-step phase shift method.The structured light based on Gray code is composed of 7 black and white fringe periodic images,and the image can be divided into 128 areas through the gray code decoding operation;the structured light based on six-step phase shift is composed of 6 cosine periodic images with phase difference.Phase shift decoding can subdivide each of the 128 areas into a single pixel.Compared with the cumbersome calculation of six Moiréfringes,the proposed structured light technology based on six-step phase-shift method has less calculation.In the simulation experiment and actual test,the proposed structured light technology showed excellent performance.