Hitoshi Hongo

Precise Top View Image Generation without Global Metric Information

We describe a practical and precise calibration method for generating a top view image that is transformed so that a planar object such as the road can be observed from a direction perpendicular to its surface. The geometric relation between the input and output images is described by a 3×3 homography matrix. Conventional methods use large planar calibration patterns to achieve precise transformations. The proposed method uses much smaller element patterns that are placed in arbitrary positions within the view of the camera. One of the patterns is used to obtain an initial homography. Then, the information from all of the patterns is used by a non-linear optimization scheme to reach a global optimum homography. The experiment done to evaluate the method showed that the precision of the proposed method is comparable to that of the conventional method where a large calibration pattern is used, making it more practical for automotive applications.

A Practical Calibration Method for Top View Image Generation

This paper describes a practical calibration method to generate a top view image from an image of a rear view camera for automobile. The geometric relation between the input and output images is described by a 3 x 3 homography matrix. Conventional methods have to use a large planar pattern to achieve precise calibration. The proposed method uses much smaller patterns, and enables to place those patterns on arbitrary positions within the view of the camera. The experimental results show that the method has equivalent calibration precision with much easier setting than the conventional methods.