For the visual form images under complex environments,an effective image segmentation method was presented.Firstly,the changes of image background were estimated by closed operation of images,and then the image background compensation was realized by defined image contrast.Then taking the mean value of the image background estimation as a global segmentation threshold of the compensation image,the form image segmentation was successfully achieved.Experimental results show that the segmentation method can obtain a good visual effect,and compared with the OSTU method based on compensation image and Niblack method based on local threshold,it can achieve a good balance between over-segmentation and under-segmentation of the image cell regions.