how to extract horizontal and vertical garadients of image.

What is mean by horizontal and vertical gradients ? Suppose if we have 41*41 matrix or image, then how we can compute its horizontal and vertical gradients ?

Answer 1

[Anthony]

Hi,

You can use the diff function. Let img be your image :

img = spiral(10); % For example
gradX = diff(img,1,1);
gradY = diff(img,1,2);
doc diff

Hope it helps,

Anthony

Answer 2

[Image Analyst]

You can imgradientxy)() in the Image Processing Toolbox. From the help:

I = imread('coins.png');
[Gx, Gy] = imgradientxy(I,'prewitt');
figure
imshowpair(Gx, Gy, 'montage');
 title('Directional Gradients: x-direction, Gx (left), y-direction, Gy (right), using Prewitt method')
axis off;

Answer 3

[pankaj chouthmal]

i have used both above methods to calculate image gradients but both answers are totally different . which one is more appropriate ?

[Image Analyst]

The one that gets the job done for you. I don't really care as long as it works.