An adaptive thresholding method for binarization of blueprint images

This paper proposes an adaptive logical thresholding method for the binarization of blueprint images. The new method exploits the geometric features of blueprint images. This is implemented by utilizing a robust windows operation, which is based on the assumption that the objects have "c" shape in a small area. We make use of multiple window sizes in the windows operation. This not only reduces computation time but also separates effectively thin lines from wide lines. Our method can automatically determine the threshold of images. Experiments show that our method is effective for blueprint images and achieves good results over a wide range of images. © 2000 Elsevier Science B.V.