Recognizing and locating the internal corners of a planar checkerboard pattern image is very important in camera calibration.An effective approach is proposed to automatically recognize and locate the internal target corners of the planar checkerboard pattern image based on the characteristics of the local intensity and the grid line architecture.Experiments show that the approach obviously reduces the time cost for camera calibration

improves the speed of calibration process and is especially adapted for automatic calibration based on multiple images.