简单验证码识别 tessnet2

今天突然间对识别验证码感兴趣，于是网上搜了一下

最简单的是引用tessnet2.dll，然后通过它来识别，代码如下

  private void button1_Click(object sender, EventArgs e)
        {
            string strUrl = @"http://www.gz.gov.cn/sofpro/gecs/common/image.jsp?dt=Thu%20Nov%2024%202011%2017:20:21%20GMT+0800%20(China%20Standard%20Time)";

            Bitmap image = GetSourceCode(strUrl);//识别图像
            pictureBox1.Image = image;
            tessnet2.Tesseract ocr= new tessnet2.Tesseract();//声明一个OCR类
            ocr.SetVariable("tessedit_char_whitelist", "0123456789"); //设置识别变量，当前只能识别数字。
            ocr.Init(Application.StartupPath+@"	mpe", "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
            List<tessnet2.Word> result = ocr.DoOCR(image, Rectangle.Empty);//执行识别操作
            string str="";
            foreach (tessnet2.Word word in result) //遍历识别结果。
                str += word.Confidence + ":" + word.Text + Environment.NewLine;
            MessageBox.Show(str);
        }

        private Bitmap GetSourceCode(string url)
        {
            WebRequest request = WebRequest.Create(url);
            WebResponse response = request.GetResponse();
            Stream st = response.GetResponseStream();
            Bitmap bitmap = (Bitmap)Bitmap.FromStream(st);
            //bitmap.Save(System.Windows.Forms.Application.StartupPath + @"	mp.bmp", System.Drawing.Imaging.ImageFormat.Bmp);
            //bitmap = (Bitmap)Bitmap.FromFile(System.Windows.Forms.Application.StartupPath + @"	mp.bmp");
            return bitmap;
        }

由于tessnet2是在netframework2.0下生成的，所以需要配置一下config文件

<configuration>
  <startup useLegacyV2RuntimeActivationPolicy="true">
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0,Profile=Client"/>
  </startup>
</configuration>

于是就可以用了

注意：http://www.gz.gov.cn/sofpro/gecs/common/image.jsp?dt=Thu%20Nov%2024%202011%2017:20:21%20GMT+0800%20(China%20Standard%20Time)是官方的一个专门是数字的一个验证码图片的网址