Identification and distortion rectification of signboards in a real scene image for robot navigation

摘要

This paper describes an approach for finding a signboard along with the camera viewing direction in a gray scene image and rectifying a distorted signboard image taken from a nonorthogonal viewing direction. First we use heuristics of both characters and character lines to discriminate characters from other objects in a gray scene image. Then, we attempt to compute the orientation of the camera relative to a detected signboard from a single view. Finally, we rectify the distortion of signboard images that are viewed at an angle. The only restriction for viewing direction estimation and distortion rectification is that a detected signboard is rectangular. We evaluate our methods on both simulation images and real scene images. Experimental results demonstrate the effectiveness of the proposed methods.