An adaptive thresholding method for binarization of blueprint Images

This paper proposes an adaptive logical thresholding method for the binariz ation of blueprint images. The new method exploits the geometric features o f blueprint images. This is implemented by utilizing a robust windows opera tion, 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 ti-om wide lines. Our method can automatically determine the thresho ld of images. Experiments show that our method is effective for blueprint i mages and achieves good results over a wide range of images. (C) 2000 Elsev ier Science B.V. All rights reserved.