Cover story: Xiang Z L, Zhang Q C, Wu Z J. 3D shape measurement and texture mapping method based on structured light projection[J]. Opto-Electron Eng, 2022, 49(12): 220169

In the traditional optical 3D measurement method, the ultimate goal is to obtain the 3D shape information of the measured object, but the 3D data that ignores the texture information often makes the measurement scene lack of realism. In order to make the obtained point cloud information more realistic and create an immersive feeling, texture mapping technique is introduced to attach color information on reconstructed 3D point cloud. Texture mapping also faces some technical problems. The first thing is how to complete color texture mapping without a color camera. Second, on the premise of using a color camera for texture recording, how to freely move the texture camera to capture the texture images from different perspectives without frequent calibration, so as to complete the accurate mapping from 3D point cloud to texture images. Therefore, robust and flexible texture mapping methods are urgent to be required to realize full color 3D imaging based on structured light.

This paper proposes a fixed-view grayscale texture mapping method and a color texture method for the case of no additional texture camera; for the case of using a color texture camera, according to whether the texture characteristics of the measured object are obvious, this paper also proposes a free texture mapping method and an unconstrained mapping method. The specific content of the paper is as follows: 

1. Under the condition that there is no color camera for texture capturing, a color projector is used to project sinusoidal fringes with three frequencies from three channels of R, G and B.

2. On the premise of taking an additional texture camera, in order to achieve the purpose that the texture camera can move freely to take texture images, and the texture images from different perspectives can successfully complete texture mapping.