## sum of absolute differences

on 30 Mar 2012
Latest activity Answered by indhumathi gunasekar

### indhumathi gunasekar (view profile)

on 29 Sep 2016
Good evening everyone,
I have two images which I seek correspondence by correlation using the sum of absolute differences (SAD) to find the disparity map.
I do not know how to apply the formula of SAD.
thank you

vimal

### vimal (view profile)

on 26 Jun 2012
You can directly use correlation method..
corr2(im1,im2) is the code for calculating the correlation between two images.
for more details type
doc corr2
in command window..

### Jan (view profile)

on 26 Jun 2012

While imabsdiff is implemented as efficient MEX (no temporary array created), you can calculate the "sum of absolute differences" easily by hand also:
img1 = rand(640, 480, 3);
img2 = rand(640, 480, 3);
difference = img1 - img2;
absolute = abs(difference);
result = sum(absolute(:));
It is less obvious for UINT8 images, because abs(uint8(10) - uint8(20)) is not uint8(10), uint8(0) due to the saturation effects. If this is not wanted, convert the UINT8 image to double at first.

### Alex Taylor (view profile)

on 30 Mar 2012

If you have the Image Processing Toolbox, consider looking at the function imabsdiff as a starting point for computing the absolute difference between two images.
help imabsdiff