Stereo line-scan sensor calibration for 3D shape measurement

The stereo line-scan sensor opens up new potentialities for 3D measurement owing to the ultra-high resolution and acquisition rate. Calibration is a crucial key technology for a stereo line-scan sensor. This paper presents a precise calibration method for the stereo line-scan sensor. Several reference points are installed onto the sensor's body as an intermediary. The calibration turns into a two-step process: calibrating the cameras in the laboratory prior to measurement and locating the sensor in an actual measurement field. A mobile apparatus that comprises a planar pattern and extra reference points is designed. By incorporating the apparatus in combination with an auxiliary instrument, an optimal calibration configuration is created by placing the apparatus into multiple positions. A robust algorithm is proposed to enhance the stability of the parameter estimation. The quality of the calibration method is experimentally tested, and the performance is further investigated. Experimental results demonstrate that the proposed method offers a practical solution to calibrate a stereo line-scan sensor for 3D shape measurement. (C) 2017 Optical Society of America