Subtract images by using opencv

Question

Hi,

I want to subtract two images. My problem ist that the cvSub()-funtion saturates. What I want to do is:

1) Convert the original images to grayscale.

2) Take the grayscale-images (values from 0-255).

3) Subtract the images (values from -255 to 255) -> problem of rescaling using cvSub().

4) Rescale by multiplying with 0.5 and adding 128.

I thought of changing the gray-scale images from 8bit to 16bit, but then everything got worse and it became many lines of code and in the end it didn't work out.

Thanks for any help.

Answer 1

You need to convert from 8bit to 16bit. Then add 255 to the first image, then subtract the second image from it. Then divide by two and convert back to 8bit.

Tell me how this goes, it should work.