In the light-sectioning method

it is difficult to accurately extract light-knife center contour under those influences such as sun light

the surface texture information and low reflection of the measured objects. This paper presents an effective solution to eliminate those influences. Firstly

controlling the laser

two consecutive images in which only one image contains laser information are acquired. Then the background motion compensation is processed

making the two images have slightly difference only in the laser location

thereby the laser trace is emerged after using the technique of the image subtraction. Finally

through the data refinement and repair

a complete light-knife center contour is obtained. The results of experiments show that the method is effective in eliminating the influences mentioned above and adapt to measure 3D shape of the mobile objects in the measure locale.