Just for the record here is he answer:
public Image<Bgr, Byte> Resize(Image<Bgr, Byte> im)
{
return im.Resize(64, 128, Emgu.CV.CvEnum.INTER.CV_INTER_LINEAR);
}
public float[] GetVector(Image<Bgr, Byte> im)
{
HOGDescriptor hog = new HOGDescriptor(); // with defaults values
Image<Bgr, Byte> imageOfInterest = Resize(im);
Point[] p = new Point[imageOfInterest.Width * imageOfInterest.Height];
int k = 0;
for (int i = 0; i < imageOfInterest.Width; i++)
{
for (int j = 0; j < imageOfInterest.Height; j++)
{
Point p1 = new Point(i, j);
p[k++] = p1;
}
}
return hog.Compute(imageOfInterest, new Size(8, 8), new Size(0, 0), p);
}
If someone else will ever need it :)