( 2 ) secondly the image after segmentation has many small grains . lines of numbers might connect short lines and might take place breakpoints . therefore binary image need amendment . this text adopts the tracking contour method of tracking contour by which grains areas is calculated and is well wiped off small grains ( 2 )二值化的身份证号码图像，会留下一些小的颗粒单元，号码线条也可能连有网格短线或发生断裂，对二值化后的号码图像进行修正。利用计算颗粒单元面积的方法对孤立单元进行去除。
