Gradient Field of an Image...

Hi,

Does anyone know how to calculate the gradient field of an image? I have checked the use of Quiver plots to achieve this, but am having difficulties applying it to an image...

Many thanks in advance for any help anyone can give!

Phil

Answer 1

[Sean de Wolski]

You can calculate the gradient using:

 doc gradient

and then use the results from that for your quiver plot.

[Philip]

Thanks! I think this should be on the right lines, but I'm having a few issues using quiver... How can I overlay the gradient field for the entire image?

I am currently using:

[gx gy] = gradient(dens,.2,.2);

figure('name','Gradient');

imshow(img(1:r,1:c),'InitialMagnification','fit');

hold on;

quiver(gx(1:r,1:c),gy(1:r,1:c));

title('Gradient Field');

And after some processing time, I just get back a completely blue figure... Do you happen to know what I am doing wrong?