Accuracy improvement of depth estimation with tilted optics and color filter aperture

Abstract

A camera-based depth estimation method is essential for self-driving. Depth estimation methods based on stereo cameras capture objects and triangulate the depth between the objects and the camera using two cameras. However, they are vulnerable to parallax distortion owing to vibrations and degradation. On the contrary, depth estimation methods based on a monocular camera, such as depth-from-defocus (DFD), use a focusing mechanism or spectroscopic optics. However, because the sharpness does not change sufficiently in the depth direction, it is not suitable for wide-range estimation. Therefore, we are developing depth-estimation methods using a monocular camera by focusing with tilted optics. When tilted optics is used, the depth of field (DOF) increases toward the depth direction, and the plane of sharp focus (POF) appears tilted. In this study, we propose to improve the accuracy of the depth estimation method using tilted optics with a color filter aperture by performing sharpness calculations corresponding to the edge direction and sharpness model fitting using the weighted least squares method.