Optical-path-difference analysis and compensation for asymmetric binocular catadioptric vision measurement

In order to determine the influence of optical path difference (OPD) in an asymmetric binocular catadioptric system, we analyzed a production law of unequal optical paths and modified a catadioptric stereovision structure. Firstly, the measurement problem caused by the OPD is analyzed based on a traditional asymmetric binocular catadioptric structure. Secondly, the reflective mirror with a shorter optical path is modified to a curved lens to compensate for the OPD. The mathematic model with an aplanatism is established in the traditional asymmetric structure. Finally, a modified design of the traditional prototype is presented depended on a planar mirror and a curved lens. Experimental results show that the demonstrated structure without the OPD is more effective for improving the measurement accuracy.