When the images collected from camera have perspective distortion

it can affect the following work such as feature extraction and object recognition due to the influence of perspective projection. When rectifying these distorted images

perspective transformation can change the relative position of inner points

while affine transformation cannot. This article will improve the Hough transformation to find the lines that hold the four points which perspective transformation needs

and then use the perspective transformation to rectify the distortion based on the imaging principle of cameras. Emulation experiment results from Matlab reveal that the algorithm can effectively rectify the distorted images and achieve our expectation. This algorithm is easy

feasible and robust

and can be applied to many fields including object recognition.