how can i apply the sobel operator in horizontal direction?

how can i apply the sobel operator in horizontal direction in matlab R2011a?

Answer 1

[Anand]

If you want the edge detected image, you can use the edge function as follows:

BW = edge(I,'sobel','vertical');

If you want just the filtered output image, you can use imfilter with a filter kernel generated by the fspecial function like so:

% generate horizontal edge emphasis kernel
h = fspecial('sobel');

% invert kernel to detect vertical edges
h = h';

J = imfilter(I,h);

Answer 2

[Image Analyst]

What does that mean? The filter is applied in both directions - over the whole image. You can align the kernel in whatever orientation you want - not sure which orientation you call horizontal.