LAUSR

Reliable detection and recognition of planar objects including traffic sign, street sign, and road surface in dynamic cluttered natural scenes are a big challenge for self-driving cars. In this paper, we propose a comprehensive method for planar object detection and recognition. First, the data association of LIDAR and camera is set up to acquire colorized laser scans, which simultaneously contain both color and geometrical information. Second, we combine three color spaces of RGB, HSV, and CIE L*a*b* with laser reflectivity as an aggregation-based feature vector. Third, the 3-D geometrical characteristics of planar objects that contain planarity, size, and aspect ratio are exploited to further reduce false alarm. Fourth, in order to increase robustness to any viewpoint variation, we present a new virtual camera-based rectification method to synthesize fronto-parallel views of refined object descriptors in 3-D space. Finally, experimental results achieved under a variety of challenging conditions show that integration of color space aggregation and laser reflectivity is superior to individuals. Specifically, the proposed perspective distortion rectification method remarkably eliminates false recognition error by 45.5%. Overall, the detection rate of our comprehensive method has up to 95.87% and the recognition rate even reaches 95.07% for traffic signs ranging within 100 m, with about 33.25 ms average running time per frame.