How to store the difference between adjacent pixel values of image

I have a black and white image and I need to store the value of the differences between each adjacent pixel so that i may plot the values in a histogram.

[DGM]

Each pixel has more than one neighbor. How many neighbors? Does the direction matter? The difference between any two pixels will be represented twice with opposite sign. Is this grayscale or an actual binary image? If it's binary, you know your histogram will only have three bins, right?

[layth ibrahim]

Starting from pixel (1,1) after that the difference with the pixel before its position. Sorry, I should have said its grayscale.

[layth ibrahim]

Was recently told I need to use a nested "for" loop to acomplish the task.

Answer 1

[Benjamin Thompson]

Use imfilter with a 1D filter argument. If your h is vertical then the difference operation is in the vertical direction. If the filter coefficients h are horizontal then the difference operation is horizontal.

>> imshow(phantom)

>> imshow(imfilter(phantom, [-1 1]))

>> imshow(imfilter(phantom, [-1 1]'))

Answer 2

[DGM]

If all you want is the difference in one direction, then just use diff().

A = randi([0 255],10);
dAdx = diff(A,1,2);

histogram(dAdx(:))