The binocular stereo vision system was established in order to automatically measure the seedling perpendicularity without touching. Firstly, the designed idea of calibration referenced objects was described and image edge tracing technique was proposed to acquire image coordinates of the control points. The simple linear method was used to calibrate two cameras in the system. Secondly, two seedling images with 24 bits color were obtained after camera calibration, and then image segmentation was performed to extract seedling from the soil background. After that, image graying and image binarization processing was implemented. In binary image, a new algorithm was proposed to express the angle information of seedling as a line for each of the two seedling images in 2D space. Finally, line reconstruction in 3D space was accomplished based on two cameras' parameter and the two simplified lines. So the seedling space angel can be calculated through the reconstructed line equation. The experiments show that the linear camera calibration method and our proposed algorithms can achieve better precision. The stereo vision measurement system can meet the need of practical application.

Date Published: 5 March 2008
PDF: 8 pages
Proc. SPIE 6623, International Symposium on Photoelectronic Detection and Imaging 2007: Image Processing, 66231D (5 March 2008); doi: 10.1117/12.791504

Published in SPIE Proceedings Vol. 6623:
International Symposium on Photoelectronic Detection and Imaging 2007: Image Processing
Liwei Zhou, Editor(s)