how can i get the horizontal and vertical pixel differences of the image

how can i get the horizontal and vertical pixel differences of the image. after that how can i combine this two images of horizontal and vertical pixel differences. finally i want to see the horizontal and vertical edges in one image.how can i do this.can any one help me with codes

Answer 1

[Walter Roberson]

diff(double(TheImage))

Answer 2

[Image Analyst]

In the Image Processing Toolbox, you can use imgradient() with the 'Roberts' filter option.