Perspective correction using camera intrinsic parameters

This paper presents a method for image perspective correction using camera intrinsic parameters. This method is based on two assumptions: a) the taken picture have a rectangle area, but didn't know the rectangle area's aspect ratio; b) the camera's intrinsic parameters should obtain by picture (Intrinsic parameters can easily obtain in iPhone or Android phone). The rectangle's perspective distortion is constrained by camera's intrinsic parameters. So this paper's method find this constraint to get the distorted rectangle's aspect ratio. Then using this ratio can get the homography matrix. This method also can be used to detect card or document rectangle area under complex background. We took some pictures by iPhones and android phones, the results shows that our method can correct document pictures' perspective distortion.