// Resize the input image and then re-compute Sobel image etc
void DetectionScanner::ResizeImage()
{
    image.Resize(sobel,ratio);
    image.Swap(sobel);
    image.Sobel(sobel,false,false);
    ComputeCT(sobel,ct);
}
// initialization -- compute the Census Tranform image for CENTRIST
void DetectionScanner::InitImage(IntImage<double>& original)
{
    image = original;
    image.Sobel(sobel,false,false);
    ComputeCT(sobel,ct);
}