Face Rotation direction detection using c# and emgucv

Question

I am new to Emgucv and I am working on face movement direction detection I had come across many codes in Internet but they are very difficult to understand.

So can you please provide a easy and understandable code or links for learning this situation.

Thanks in advance

Answer 1

Based on this :

Bitmap bmp = new Bitmap(); // your bitmap contain a face
Mat mat = GetMatFromSDImage(bmp);
using (var nextFrame = mat.ToImage<Bgr, Byte>())
{
    if (nextFrame != null)
    {
        Image<Gray, byte> grayframe = nextFrame.Convert<Gray, byte>();
        Rectangle[] faces = mHaarCascade.DetectMultiScale(grayframe, 1.1, 10, Size.Empty);
        if (faces.Count() > 0)
        {
            // some faces are detected
            // you can check the X and Y of faces here
        }
    }
}

private Mat GetMatFromSDImage(Bitmap image)
{
    int stride = 0;

    System.Drawing.Rectangle rect = new System.Drawing.Rectangle(0, 0, image.Width, image.Height);
    System.Drawing.Imaging.BitmapData bmpData = image.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite, image.PixelFormat);

    System.Drawing.Imaging.PixelFormat pf = image.PixelFormat;
    if (pf == System.Drawing.Imaging.PixelFormat.Format32bppArgb)
    {
        stride = image.Width * 4;
    }
    else
    {
        stride = image.Width * 3;
    }

    Image<Bgra, byte> cvImage = new Image<Bgra, byte>(image.Width, image.Height, stride, (IntPtr)bmpData.Scan0);

    image.UnlockBits(bmpData);

    return cvImage.Mat;
}

so faces contains the array of Rectangle bounding faces. you can check the X and Y property of the rectangles to check if it moves and compares it with the initial position to detect it's direction.

Update based on comment
To detect head rotation a simple solution can be eye detection. you can use haarcascade_eye.xml to detect ayes. then you can calculate the rotation form each eye's X and Y position.

Here you can find a simple example of eye detection