Finding gradient differences in code?

Hi,

I'm finding edges using the gradient function.

[Gx, Gy] = gradient(imgaussfilt(im, gradientsigma), 'x', 'y');

In this code, what does the 'x' and 'y' do? I've tried removing them to see if I get the same answer (I don't) but I don't understand the difference?

Many thanks!

[darova]

2d and 3d inputs of gradient are steps in X and Y directions. I don't know why it's working with symbolic 'x' and 'y'

Answer 1

[Ameer Hamza]

This uses an undocumented syntax of the gradient(). Modern documentation no longer mentions this syntax; however it is still supported, probably due to backward compatibility. Even the documentation of 2013a does not mention this: https://www.mathworks.com/help/releases/R2013a/matlab/ref/gradient.html and documentation older than that are not available online. Unless someone remembers this old syntax, it is unlikely that you can find much more information.

Use this modern variant to find the gradient of an image: https://www.mathworks.com/help/images/ref/imgradient.html

[Mia]

Ah okay, thank you!