Image-based system for measuring objects on an oblique surface

This paper presents an image-based framework for measuring target objects on an oblique plane by using a single CCD camera and two parallel laser projectors beside the camera. Because of the alignment of the laser beams which form in parallel with the optical axis, projected spots in the image can be processed to establish relationships between distance and pixel counts between the projected spots in the image. Based on simple geometrical derivations without complex image processing, the proposed approach can measure the photographing distance, the distance between two arbitrary points on the oblique surface, and the incline angle. Experiment results have demonstrated the effectiveness of the proposed approach in measuring distant objects on an oblique plane.