Fast Detection of Ground Plane in Stereo Vision Systems Based on Iso-Disparity Strip Pattern

In this paper, first a closed-form formulation is analytically derived for the pattern of iso-disparity strip widths associated with the ground plane in disparity map images. This formulation calculates the iso-disparity strip widths based on the parameters of the stereo camera setup (i.e., height, tilt angle, and baseline of the cameras) used to capture the images. The proposed formulation was then statistically validated using the results achieved in the case of a bank of stereo image pairs with different stereo camera setup parameters. Validation of the proposed formulation was in the presence of the strip width imperfections that appear in reality, and were shown to be in the form of additive Gaussian noise. Using the formulation proposed for iso-disparity strip widths, the paper then introduces a novel approach for ground plane detection based on the concept of iso-disparity strips in disparity map images. To add to the robustness of the proposed procedure against strip width noise, Cumulative Moving Average (CMA) and a dynamic thresholding technique are used to find the width of the strips corresponding to the ground plane. According to experimental results for synthesized and captured datasets, while exhibiting sufficiently low false positive rates (1.38% and 5.83%), the proposed method detects the ground plane with average true positive rates of as high as 80% and 54% in 65 ms and 224 ms, respectively.