图片比较算法.docVIP

图片比较算法 上一篇 / 下一篇 ?2008-12-31 11:11:32 / 个人分类：自动化测试框架 查看( 151 ) / 评论( 1 ) / 评分( 0 / 0 ) 前几天其他项目组接了个项目，客户那边要求顺便给做个图片比较的工具，因为他们要看看同样的网页在IE7和IE8上显示有什么不同，不同的地方用用户指定的某种颜色标示出来，生成第三张图片。因为他们组比较忙，就帮他们做了做，UI界面就不用说了。 起初的想法是这样，先比较两幅图片的hash散列，如果相同就不比较了，下面就是这个算法： ??????? /// summary??????? /// compare the hash value of two image files.??????? /// /summary??????? /// param name=leftImage/param??????? /// param name=rightImage/param??????? /// returns/returns??????? private static bool HashCompare(Bitmap leftImage, Bitmap rightImage)??????? {??????????? if (leftImage.Size != rightImage.Size)??????????? {??????????????? return false;??????????? } ??????????? byte[] buffer = new byte[1];??????????? byte[] buffer2 = new byte[1];??????????? ImageConverter converter = new ImageConverter();??????????? buffer = (byte[])converter.ConvertTo(leftImage, buffer.GetType());??????????? buffer2 = (byte[])converter.ConvertTo(rightImage, buffer2.GetType());??????????? SHA256Managed managed = new SHA256Managed();??????????? byte[] buffer3 = managed.ComputeHash(buffer);??????????? byte[] buffer4 = managed.ComputeHash(buffer2); ??????????? for (int i = 0; (i buffer3.Length) (i buffer4.Length); i++)??????????? {??????????????? if (buffer3[i] != buffer4[i])??????????????? {??????????????????? return false;??????????????? }??????????? } ??????????? return true;??????? } 如果hash散列不同，就挨个像素比较，可这样有个问题，就是两幅图片有时候其实我们看起来是一样的，但是实际上你取他们像素的时候他们是不同的，如果我们将用户都不能分辨出不同的地方都标示出来意义不大，于是最后决定只比较像素的R.G.B，只要他们相同就行（这里的相同也做了妥协，就是两个像素的R.G.B值也允许有一定的误差）,最后算法如下： ?? /// summary??????? /// compare two bitmaps.??????? /// /summary??????? /// param name=leftImagethe first bitmap/param??????? /// param name=rightImagethe second bitmap/param??????? /// param name=resultImageFullPaththe result bitmap/param??????? /// returnsreturn the comparision result/returns??????? public static bool Compare(Bitmap leftImage, Bitmap rightImage, string resultImageFullPath)??????? {??????????? bool matched = true; ???