The most critical step in three-dimensional measurement is to extract laser stripe in structured light image. In indoor environment

luminance of light bar in image becomes inconsistent due to influence of distance from the measured object to light source and change of background gray level. In addition

the ambient light will interfere with the process of light bar extraction. Aiming at this problem

a method combining threshold

edge detection and gray distribution feature is proposed. First

use the threshold method to extract the light bar with higher luminance and eliminate ambient light disturbance with edge detection. Then extract light bar with lower luminance according to characteristics of gray distribution. Experimental result shows that light bar can be extracted fastly and accurately with this method in indoor complicated background environment.