private void teachButton_Click(object sender, EventArgs e)
{
_terminate = false;
_error = 1.0;
_progress = 0;
_terminated = false;
_controlError = -1;
_updateProgress();
new Thread(() =>
{
var samples = CaptchasLibrary.GetRecognizedCaptchas();
var digitImages = new List <Image>();
var digitResults = new List <int>();
int controlStart = (int)(samples.Count * 0.8);
for (var i = 0; i < controlStart; i++)
{
var recognizer = new CaptchaRecognizer(samples[i].Image);
var rectangles = recognizer.SplitDigits();
for (var j = 0; j < rectangles.Length; j++)
{
digitImages.Add(ImageHelper.Crop(recognizer.Target, rectangles[j]));
digitResults.Add(int.Parse(samples[i].Answer.Substring(j, 1)));
}
}
var teacher = new NeuralNetworkTrainer(digitImages.ToArray(), digitResults.ToArray());
teacher.Run((net, data, epochs, reports, er, u, userData) =>
{
_error = net.MSE;
_progress = 1.0 * u / epochs;
if (_terminate)
{
return(-1);
}
return(0);
});
teacher.Network.Save(CaptchaRecognizer.NetworkPath);
var controlTotal = 0;
var controlPasses = 0;
for (var i = controlStart; i < samples.Count; i++)
{
var rec = new CaptchaRecognizer(samples[i].Image);
var res = rec.Recognize();
controlTotal++;
if (res.Result == samples[i].Answer)
{
controlPasses++;
}
}
_controlError = 1.0 * controlPasses / controlTotal;
_error = teacher.Network.MSE;
_terminate = true;
_terminated = true;
_progress = 1;
}).Start();
}
private string _process(HttpListenerContext context)
{
var rand = context.Request.QueryString["rand"];
var url = context.Request.QueryString["url"];
var errorStr = "{\"status\": \"error\"}";
if (url == null)
{
return(errorStr);
}
var captcha = new Captcha
{
Name = rand,
Source = url,
};
try
{
captcha.Download();
}
catch (Exception)
{
return(errorStr);
}
var tries = 5;
var results = new List <CaptchaRecognizer.RecognizeResult>();
for (var tryNo = 0; tryNo < tries; tryNo++)
{
var rec = new CaptchaRecognizer(captcha.Image);
try
{
var res = rec.Recognize();
results.Add(res);
if (res.Probability > 0.9)
{
break;
}
}
catch (CaptchaRecognizer.CantSplitDigitsException)
{
results.Add(new CaptchaRecognizer.RecognizeResult
{
Probabilities = new double[] { 0, 0, 0, 0 },
Result = "1111"// just random string
});
}
}
var result = results.OrderByDescending(x => x.Probability).First();
return("{\"status\": \"OK\", \"result\": \"" + result.Result + "\", \"probability\": \"" + result.Probability + "\"}");
}