Calculating a partial derivative in an 3D image

I have a 3D image (I) and I want to calculate the partial derivatives d(I)/dxdy, d(I)/dxdz, d(I)/dydz. I know that matlab has the functions imgradient, but I don't know how to calculate this.

Thanks for all the support.

Answer 1

[Matt J]

You could use diff, e.g.,

dIdxdy = diff( diff(I,1,1), 1,2);

Or, for maximum flexibility, you could use convolution. For example, if you want central differences,

dx=[1;0;-1];
dy=dx.';

dIdxdy=convn(  convn(I,dx,'same')   ,dy,'same');

[Felippe Trigueiro Angelo]

Thank you very much for the answer.