3D laser scanner system using high dynamic range imaging

Abstract

Because of its high measuring speed, moderate accuracy, low cost and robustness in the industrial field, 3D laser scanning has been widely used in a variety of applications. However, the measurement of a 3D profile of a high dynamic range (HDR) brightness surface such as a partially highlighted object or a partial specular reflection remains one of the most challenging problems. This difficulty has limited the adoption of such scanner systems. In this paper, an optical imaging system based on a high-resolution liquid crystal on silicon (LCoS) device and an image sensor (CCD or CMOS) was built to adjust the image's brightness pixel by pixel as required. The radiance value of the image captured by the image sensor is constrained to lie within the dynamic range of the sensor after an adaptive algorithm of pixel mapping between the LCoS mask plane and image plane through the HDR imaging system is added. Thus, an HDR image was reconstructed by the LCoS mask and the CCD image on this system. The significant difference between the proposed system and a traditional 3D laser scanner system is that the HDR image was used to calibrate and calculate the 3D profile coordinate. Experimental results show that HDR imaging can enhance 3D laser scanner system environmental adaptability and improve the accuracy of 3D profile measurement.