问题
I was working on Face Recognition project. After training the database and calling EigenObjectRecognizer, the result is a black image with unrecognized label.When the code runs, it looks like the following http://www.mediafire.com/view/?ewns4iqvd51adsc .And as shown in the picture the detected and supposed to be recognized and extracted face in the image box is totally black. And the input image for recognition is exactly the same as the one the database is trained with.So why it has kept giving Unknown or Unrecognized result. Part of the code looks
Images from the training set loaded as
public FaceRecognizer()
{
InitializeComponent();
//Load faces from the dataset
try
{
ContTrain = ContTrain + 1;
//Load previous trained and labels for each image from the database Here
string NameLabelsinfo = File.ReadAllText(Application.StartupPath +
"/TrainedFaces/TrainedNameLables.txt");
string[] NameLabels = NameLabelsinfo.Split('%');
NumNameLabels = Convert.ToInt16(NameLabels[0]);
string IDLabelsinfo = File.ReadAllText(Application.StartupPath +
"/TrainedFaces/TrainedNameLables.txt");
string[] IDLables = IDLabelsinfo.Split('%');
NumIDLabels = Convert.ToInt16(IDLables[0]);
if (NumNameLabels == NumIDLabels)
{
ContTrain = NumNameLabels;
string LoadFaces;
// Converting the master image to a bitmap
for (int tf = 1; tf < NumNameLabels + 1; tf++)
{
LoadFaces = String.Format("face{0}.bmp", tf);
trainingImages.Add(new Image<Gray, byte>(String.Format("
{0}/TrainedFaces/{1}", Application.StartupPath, LoadFaces)));
IDLabless.Add(IDLables[tf]);
NameLabless.Add(NameLabels[tf]);
}
}
}
catch (Exception e)
{
//Returns the following message if nothing saved in the training set
MessageBox.Show("Nothing in binary database, please add at least a
face(Simply train the prototype with the Add Face Button).", "Triained
faces load",MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
}
}
The face recognizer method looks like
private void RecognizeFaces()
{
//detect faces from the gray-scale image and store into an array of type
// 'var',i.e 'MCvAvgComp[]'
Image<Gray, byte> grayframe = GetGrayframe();
stringOutput.Add("");
//Assign user-defined Values to parameter variables:
MinNeighbors = int.Parse(comboBoxMinNeigh.Text); // the 3rd parameter
WindowsSize = int.Parse(textBoxWinSiz.Text); // the 5th parameter
ScaleIncreaseRate = Double.Parse(comboBoxScIncRte.Text); //the 2nd
//parameter
//Detect faces from an image and save it to var i.t MCvAcgComp[][]
var faces = grayframe.DetectHaarCascade(haar, ScaleIncreaseRate,
MinNeighbors,
HAAR_DETECTION_TYPE.DO_CANNY_PRUNING,
new Size(WindowsSize, WindowsSize))[0];
if (faces.Length > 0 && trainingImages.ToArray().Length != 0)
{
Bitmap ExtractedFace; //empty
ExtFaces = new Image<Gray, byte>[faces.Length];
faceNo = 0;
foreach (var face in faces)
{
// ImageFrame.Draw(face.rect, new Bgr(Color.Green), 3);
//set the size of the empty box(ExtractedFace) which will later
//contain the detected face
ExtractedFace = new Bitmap(face.rect.Width, face.rect.Height);
ExtFaces[faceNo] = new Image<Gray, byte>(ExtractedFace);
ExtFaces[faceNo] = ExtFaces[faceNo].Resize(100, 100,
Emgu.CV.CvEnum.INTER.CV_INTER_CUBIC);
//TermCriteria for face recognition with numbers of trained images
// like maxIteration
MCvTermCriteria termCrit = new MCvTermCriteria(ContTrain, 0.001);
//Eigen face recognizer
EigenObjectRecognizer recognizer = new EigenObjectRecognizer(
trainingImages.ToArray(),
NameLabless.ToArray(),
700,
ref termCrit);
stringOutput[faceNo] = recognizer.Recognize(ExtFaces[faceNo]);
stringOutput.Add("");
faceNo++;
}
pbExtractedFaces.Image = ExtFaces[0].ToBitmap(); //draw the face detected
// in the 0th (gray) channel with blue color
if (stringOutput[0] == "")
{
label1.Text = "Unknown";
label9.Text = "";
}
//Draw the label for each face detected and recognized
else
{
//string[] label = stringOutput[faceNo].Split(',');
label1.Text = "Known";
// for (int i = 0; i < 2; i++)
//{
label9.Text = stringOutput[0];
//label7.Text = label[1];
//}
}
}
if (faceNo == 0)
{
MessageBox.Show("No face detected");
}
else
{
btnNextRec.Enabled = true;
btnPreviousRec.Enabled = true;
}
}
The training set is trained with detected faces as follows
private void saveFaceToDB_Click(object sender, EventArgs e)
{
abd = (Bitmap) pbExtractedFaces.Image;
TrainedFaces = new Image<Gray, byte>(abd);
trainingImages.Add(TrainedFaces);
NameLabless.Add(StudentName.Text);
IDLabless.Add(StudentID.Text);
//Write the number of trained faces in a file text for further load
File.WriteAllText(Application.StartupPath + "/TrainedFaces
/TrainedNameLables.txt", trainingImages.ToArray().Length + "%");
File.WriteAllText(Application.StartupPath + "/TrainedFaces
/TrainedIDLables.txt", trainingImages.ToArray().Length + "%");
//Write the labels of trained faces in a file text for further load
for (int i = 1; i < trainingImages.ToArray().Length + 1; i++)
{
trainingImages.ToArray()[i - 1].Save(String.Format("{0}/TrainedFaces
/face{1}.bmp", Application.StartupPath, i));
File.AppendAllText(Application.StartupPath + "/TrainedFaces
/TrainedIDLables.txt", NameLabless.ToArray()[i - 1] + "%");
File.AppendAllText(Application.StartupPath + "/TrainedFaces
/TrainedNameLables.txt", IDLabless.ToArray()[i - 1] + "%");
}
MessageBox.Show(StudentName.Text + "´s face detected and added :)", "Training
OK", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
Thanks
来源：https://stackoverflow.com/questions/16512362/face-recognition-code-using-emgu-cv-and-c-sharp-and-it-returns-a-black-image-and