An Image Binarization Method of Government Document Resource
一种政府资源档案图像的二值化方法

For the gray-level image of government document resource,a linear transform is employed to enhance the image contrast.A spatial filter is applied to bate image noise.Based on this preprocessing,the global threshold T2 is calculated by modified Otsu method.The threshold surface T1 is computed by Bernsen algorithm.On the basis of T1 and T2,some thresholds such as the stroke breaking value T3,the average value T4 of local processing window and the union value T5 between global and local are defined.Then the gray-level image is binarized through the combination of these five values.Our experiments show that the proposed method,based on the union of global and local threshold,is adaptive to various documents of government resource.It can achieve our purpose of processing of image ghost and broke rupture.