ABSTRACT
After analysis of the 3D human face scanning technology at home and abroad, based on laser triangulation principle, in accordance with the requirements of high resolution and short scanning time, a project of three-line structured light laser 3D human face scanning has been proposed. The hardware and software of the system were designed with the key technology studied. The prototype of the system was developed successfully. Scanning experiments were carried out and the expected results verified the correctness of the system. The main work includes:
According to the actual requirements, a project of three-line structured light laser 3D human face scanning was proposed. Three parallel structured light with the same distance in the height direction were projected from three lasers in the same type. When scanning, each laser should move 1/3 of the entire scanning range which meets the requirement of reducing the scanning time of the system.
The general structure of the system were designed which included sensors, motion system, image capture system and computer processing system. The control program has been completed which realized the synchronous running of the image capture system and motion system. The technical indexes of the system reach that: scanning range of 220mm×250mm×100mm(W×H×D), typical resolution of 0.4mm×0.4mm×0.5mm(W×H×D), scanning time of 7 seconds.
By establishing the ideal linear mode and the distortion model of the camera, the mapping relationship between the 3D world coordinates and the computer image coordinates has been deduced. Zhang Zhengyou calibration algorithms and camera perspective transformation matrix calibration method were combined to carry out calibration to the sensor. The intrinsic parameters and external parameters of the system were obtained.
After debugging the system and processing the actual scanning experiment, the point cloud of the face model was obtained. By resampling of the point cloud, the camera resolution of the three-line structured light reached the same. The original point cloud and the resampling point cloud were reconstructed to receive the mesh model. By scanning the standard gauge block, the relative measurement error of the system was less than 0.25%.
By combining the binocular stereo vision and active laser scanning, a project of three-line structured light scanning with the camera fixed was proposed. Point cloud and reconstruction model of the face were obtained. The two methods of three-line structured light laser scanning and binocular vision were compared.