A ruled-line extraction method for digital camera images

We propose a high-accuracy ruled-line extraction method for digital camera images containing shadows. The conventional method that uses adaptive binarization has a problem in that light line segments become blurred due to the adverse effect of the adaptive binarization process. Then, we propose an accurate method which uses an intentionally collapsing binary image as a clue and exploits the linearity and gray level stability of each line segment. By the experiment, we demonstrated the effectiveness of the proposed method, which reduced the extraction error by half.