基于结构光的镜面/漫反射复合表面形貌测量

Shape measurement of specular/diffuse complex surface based on structured light

光学三维测量技术以其非接触、无损及快速测量的优势被广泛应用于不同领域。已有的条纹投影和条纹反射测量术分别适用于漫反射表面和镜面表面。然而,航空航天和先进制造中存在许多漫反射和镜面反射表面同时存在的复合反射表面。提出一种基于结构光投影和反射的方法来实现复合表面形貌的快速测量。首先,投影仪投射蓝色正弦条纹图于被测物体表面,同时显示屏显示的红色条纹被镜面部分反射。其次,彩色相机采集经被测表面调制的变形条纹图。然后,从相机不同颜色通道中提取对应不同类型反射表面的变形条纹,并计算变形条纹图的绝对相位。最后,通过系统标定建立相位信息与深度之间的直接关系,得到被测复合表面的三维形貌。实验结果表明:该方法不仅能够有效地实现非连续复合表面物体的测量,还能够同时测量独立的漫反射和镜面反射表面的三维形貌。

Optical three-dimensional(3D) measurement technology is widely used in different fields due to its advantages of non-contact, non-destructive and rapid measurement. The existing technologies of Fringe Projection Measurement and Fringe Reflection Measurement are designed for the measurement of diffusely reflective and specularly reflective surfaces respectively. However, there are many complex surfaces which have both diffused and specular reflective surfaces together in aerospace and advanced manufacturing. In this paper, a method based on structured light projection and reflection was proposed to realize rapid measurement of complex surfaces. First, a Digital Light Projector(DLP) projected blue sinusoidal fringe onto the tested surface, and red fringes displayed by a screen were reflected by its specular part simultaneously. Second, deformed fringe patterns modulated by the measured surface were captured by a color Charge Coupled Device(CCD) camera. Then,deformed fringes of different reflection surface were extracted from different color channels of the camera and then absolute phase information could be calculated. Finally, after system calibration to build up the relationship between phase and depth, 3D shape data of the measured complex object was obtained. Experimental results show that the proposed method can not only measure complex surfaces effectively, but obtain 3D shape of isolated diffused and specular surfaces simultaneously.