Abstract: View the effect of between-class(between object and background) scatter and within-class scatter in the image imultaneously in the field of ability of classification,image thresholding segmentation method based on 2-D(dimensional) ound histogram and Fisher criterion is proposed.First,the bound set of an image and its corresponding two-dimension ound histogram is constructed considering the center pixel and its neighbor pixels.Then using the maximizing the Fisher riterion,the 2-D threshold vector is obtained,and in order to reduce the computation complexity,a fast recursive algorithm s presented.In the fast recursive algorithm,the computation of 2-D Fisher criterion is written in recursive form,so that many epeated calculations are avoided.Experimental results show that the proposed method can not only obtain ideal segmentation esults but also decrease the computation cost reasonably,and it is suitable for real time application.