Applying dithering to improve depth measurement using a sensor-shifted stereo camera

The sensor-shifted stereo camera provides the mechanism for obtaining 3D information in a wide field of view. This novel kind of stereo requires a simpler matching process in comparison to convergence stereo. In addition to this, the uncertainty of depth estimation of a target point in 3D space is defined by the spatial quantization caused by the digital images. The dithering approach is a way to reduce the depth reconstruction uncertainty through a controlled adjustment of the stereo parameters that shift the spatial quantization levels. In this paper, a mathematical model that relates the stereo setup parameters to the iso-disparities is developed and used for depth estimation. The enhancement of the depth measurement accuracy for this kind of stereo through applying the dithering method is verified by simulation and physical experiment. For the verification, the uncertainty of the depth measurement using dithering is compared with the uncertainty produced by the direct triangulation method. A 49% improvement of the uncertainly in the depth reconstruction is proved.