Robust Inverse Perspective Mapping Based On Vanishing Point

Inverse perspective mapping(IPM) has been widely used in computer vision and road traffic makings detection and recognition. Inverse perspective mapping is the inverse process of perspective mapping. It maps the image from the image coordinates to the world coordinate by a combination of intrinsic and extrinsic parameters of the camera, and eliminate the perspective effect. Therefore, a robust inverse perspective mapping method plays a very important role in eliminating the perspective influence and obtaining the invariant information of the image. This paper studies the robust inverse perspective mapping methods based on the vanishing point and its application. It calculates the deflection angle of the inverse perspective mapping parameters based on the vanishing point automatically, and then uses the inverse perspective mapping to detect and recognize the arrow road markings.Firstly, this paper concludes the background and significance of robust inverse mapping based on vanishing point, summarizes the research status of existing inverse perspective mapping algorithms and the existing problems.Secondly, this paper introduces the basic concepts and the mathematical principles of inverse perspective mapping. The inverse perspective mapping has widely been used in road traffic markings detection. The common inverse perspective mapping methods were divided into three categories based on the calculation of transformation parameters: the inverse perspective mapping based on the corresponding points, the inverse perspective mapping based on the transformation matrix and the inverse perspective mapping based on simplified camera model. It summarizes the three existing inverse perspective mapping methods and describes their advantages and disadvantages. Among them, this paper mainly describes the inverse perspective mapping based on the simplified camera model, because such an inverse perspective mapping method is simple and with high practical value.Thirdly, this paper presents a robust inverse perspective mapping method based on vanishing point detection. Vanishing point reflects the perspective structure of the image, the coordinates of the vanishing point can be used to calculate the camera pitch angle and yaw angle and provide real-time deflection angle parameters for inverse perspective mapping. It is more robustness to the downhill road and other unconventional road environment. At the same time, this paper improves image quality of an inverse perspective mapping result by the yaw angle correction. The proposed method firstly detected vanishing point, and then calculate the pitch angle and yaw angle according to the vanishing point, and finally get a top view of the road without perspective distortion through the inverse perspective mapping.Finally, the inverse perspective mapping method is used to detection and recognition of the arrow road markings. Arrow road makings is a kind of road traffic markings, which has an important indication function to regulate vehicle travel. Therefore, the detection and recognition of arrow road markings can provide important guide information to intelligent transportation systems. Firstly, it use the inverse perspective mapping method to eliminate the perspective influence of the road plane, and then detect the candidate region of arrow road markings, and then extract the shape feature by using shape contexts, at last the shape matching based on ant colony optimization algorithm is used to recognize the arrow road makings.