C#调用开源图像识别类库tessnet2

1.        private tessnet2.Tesseract ocr = new tessnet2.Tesseract();//声明一个OCR类  
2.   
3.   
4.             //程序开始的时候，初始化OCR  
5.        ocr.SetVariable("tessedit_char_whitelist", "0123456789."); //设置识别变量，当前只能识别数字。  
6.         ocr.Init(@"D:\tessdata", "eng", false); //应用当前语言包。注，Tessnet2是支持多国语的。语言包下载链接：http://code.google.com/p/tesseract-ocr/downloads/list  
7.   
8.   
9. //下边这个函数是将网络上的图片识别成字符串，传入图片的超链接，输出字符串  
10.   
11.         public string Bmp2Str(string bmpurl)  
12.   
13.         {  
14.             //http://www.newwhy.com/2010/0910/13708.html  
15.             string s = "0";  
16.             WebClient wc = new WebClient();  
17.             try  
18.             {  
19.                 byte[] oimg = wc.DownloadData(bmpurl);//将要识别的图像下载下来  
20.                 MemoryStream ms = new MemoryStream(oimg);  
21.                 Bitmap image = new Bitmap(ms);  
22.   
23.   
24. //为了提高识别率，所以对图片进行简单的处理  
25.                 image = BlackAndWhite(image, 0.8);//黑白处理，这个函数看下边  
26.                 image = new Bitmap(image, image.Width * 3, image.Height * 3);//放大三倍  
27.                   
28.                 Monitor.Enter(this);//因为是多线程，所以用到了Monitor。  
29.                 System.Collections.Generic.List<tessnet2.Word> result = ocr.DoOCR(image, Rectangle.Empty);//执行识别操作  
30.                 foreach (tessnet2.Word word in result) //遍历识别结果。  
31.                     s = s + word.Text;  
32.                 Monitor.Exit(this);  
33.                 if (s.Length > 2)  
34.                     s = s.Substring(2, s.Length - 2);  
35.   
36.             }  
37.             catch  
38.             {  
39.                 s = "0";  
40.             }  
41.             finally  
42.             {  
43.                 wc.Dispose();  
44.             }  
45.             return s;  
46.   
47.   
48.             //Console.WriteLine("{0} : {1}", word.Confidence, word.Text);   
49.         }  
50.   
51.   
52.   
53.   
54.   
55. //黑白处理的函数，网上查的。  
56.   
57.         public static Bitmap BlackAndWhite(Bitmap bitmap, Double hsb)  
58.         {  
59.             if (bitmap == null)  
60.             {  
61.                 return null;  
62.             }  
63.   
64.   
65.             int width = bitmap.Width;  
66.             int height = bitmap.Height;  
67.             try  
68.             {  
69.                 Bitmap bmpReturn = new Bitmap(width, height, PixelFormat.Format1bppIndexed);  
70.                 BitmapData srcBits = bitmap.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);  
71.                 BitmapData targetBits = bmpReturn.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadWrite, PixelFormat.Format1bppIndexed);  
72.   
73.   
74.                 unsafe  
75.                 {  
76.                     byte* pSrcBits = (byte*)srcBits.Scan0.ToPointer();  
77.                     for (int h = 0; h < height; h++)  
78.                     {  
79.                         byte[] scan = new byte[(width + 7) / 8];  
80.                         for (int w = 0; w < width; w++)  
81.                         {  
82.                             int r, g, b;  
83.                             r = pSrcBits[2];  
84.                             g = pSrcBits[1];  
85.                             b = pSrcBits[0];  
86.   
87.   
88.                             if (GetBrightness(r, g, b) >= hsb) scan[w / 8] |= (byte)(0x80 >> (w % 8));  
89.                             pSrcBits += 3;  
90.                         }  
91.                         Marshal.Copy(scan, 0, (IntPtr)((int)targetBits.Scan0 + targetBits.Stride * h), scan.Length);  
92.                         pSrcBits += srcBits.Stride - width * 3;  
93.                     }  
94.                     bmpReturn.UnlockBits(targetBits);  
95.                     bitmap.UnlockBits(srcBits);  
96.                     return bmpReturn;  
97.                 }  
98.             }  
99.             catch  
100.             {  
101.                 return null;  
102.             }  
103.   
104.   
105.         }  

找到了
private static float GetBrightness(int r, int g, int b)
{
float fR = ((float)r) / 255f;
float fG = ((float)g) / 255f;
float fB = ((float)b) / 255f;
float fMax = fR;
float fMin = fR;

fMax = (fG > fMax) ? fG : fMax;
fMax = (fB > fMax) ? fB : fMax;

fMin = (fG < fMax) ? fG : fMax;
fMin = (fB < fMax) ? fB : fMax;

return ((fMax + fMin) / 2f);

}