In analyzing the various types of image-based scoring system, the key techniques of camera-based information-card scoring system are given: uneven illumination of the image processing, lens distortion correction image processing. This paper proposes binarization image processing with the local average threshold to solve the problem of uneven illumination. It uses rectangular corner-based geometric aberra- tion transform image correction algorithm, which include two steps to complete the correction skew dis- tortion and perspective distortion. It also gives the transformation formula. Practice shows that this method performs well, and meets the functional requirements.