C#编程小实例（二）（Compare two images with C# 用C#比较两个图片）（未看）

This is a snippet to compare 2 images to see if they are the same. This method first converts each Bitmap to a byte array, then gets the hash of each array. We then loop through each in the hash to see if they match

 

Language: C#

Last Modified: January 7, 2009

Instructions: Need a reference to the following:

System.Drawing
System.Security.Cryptography

Provide the method with 2 bitmaps

Snippet

1. /// <summary>
2. /// method for comparing 2 images to see if they are the same. First
3. /// we convert both images to a byte array, we then get their hash (their
4. /// hash should match if the images are the same), we then loop through
5. /// each item in the hash comparing with the 2nd Bitmap
6. /// </summary>
7. /// <param name="bmp1"></param>
8. /// <param name="bmp2"></param>
9. /// <returns></returns>
10. public bool doImagesMatch(ref Bitmap bmp1, ref Bitmap bmp2)
11. {
12.     try
13.     {
14.         //create instance or System.Drawing.ImageConverter to convert
15.         //each image to a byte array
16.         ImageConverter converter = new ImageConverter();
17.         //create 2 byte arrays, one for each image
18.         byte[] imgBytes1 = new byte[1];
19.         byte[] imgBytes2 = new byte[1];
20.  
21.         //convert images to byte array
22.         imgBytes1 = (byte[])converter.ConvertTo(bmp1, imgBytes2.GetType());
23.         imgBytes2 = (byte[])converter.ConvertTo(bmp2, imgBytes1.GetType());
24.  
25.         //now compute a hash for each image from the byte arrays
26.         SHA256Managed sha = new SHA256Managed();
27.         byte[] imgHash1 = sha.ComputeHash(imgBytes1);
28.         byte[] imgHash2 = sha.ComputeHash(imgBytes2);
29.  
30.         //now let's compare the hashes
31.         for (int i = 0; i < imgHash1.Length && i < imgHash2.Length; i++)
32.         {
33.             //whoops, found a non-match, exit the loop
34.             //with a false value
35.             if (!(imgHash1[i] == imgHash2[i]))
36.                 return false;
37.         }
38.     }
39.     catch (Exception ex)
40.     {
41.         MessageBox.Show(ex.Message);
42.         return false;
43.     }
44.     //we made it this far so the images must match
45.     return true;
46. }