For the characteristics of binocular stereo measurement system based on random pattern projection

a novel method for measurement was presented

where each monocular measurement system was composed of single camera and the projector. First

a simple and effective calibration algorithm was proposed to reconstruct the ray

which every point of the random pattern plate projected through projector lens. The calibration was done by just taking several images (called calibrated images) of the common white board with random illumination in different orientations. It is unnecessary to calibrate the distortion of projector lens

and its precision can tolerate the effect of the distortion of projector lens. Then

the object’s image captured in random illumination was matched with the calibrated image at sub-pixel location

and the 3D point cloud data of the target object were obtained by triangulation principle. Finally

a standard plane was measured to verify the measuring accuracy of monocular method

and several measurement examples were concretely provided. Experimental results indicate that the precision of flat measurement is 0.0175mm

and the uncertainty is 0.05mm(3σ). Since a space point does not need to be observed by both cameras in monocular measurement system

it avoids losing 3D data resulted from local highlight and self occlusion

and effectively makes up for the lack of binocular measurement system.