emgu diffence of gaussian filter returns black image

Question

I'm trying to implement DoG filter in emgu like this:

Image <Gray, byte> temp  = inImage;
Image <Gray, byte> temp2 = inImage;
temp1._SmoothGaussian(1);
temp2._SmoothGaussian(3) 
result= temp2.Sub(temp);
result.ToBitmap().Save("DoG.bmp");

Problem is that result image is all black (I checked temp1 and temp2, they are different and both have gaussian filter correctly applied)

Do you have any hint, where could be problem?

Answer 1

Maybe the difference is small, so you can't visualize it directly. (If the difference is between 0 and 10, it will be very dark and all pixels will seem to be black).

You should do adapt the difference image between 0 and 255 if you want to see it well.