How to compute horizontal gradient value?

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So I want to measure the vertical edges of an image to use it later as depth cue for 2D to 3D conversion.

To do so I will have to compute the horizontal gradient value for each block to measure the vertical edges as follow:

̅ g(x,y) = 1/N  ∑_((x',y')∈ Ω(x,y))〖g(x', y')〗

Where:

g(x',y') is a horizontal gradient at a pixel location (x',y'),

omega(x,y) is the nighborhood of the pixel location(x',y')

and N is the number of pixels in omega(x,y).

So Here is what I did on matlab:

I = im2double(imread('landscape.jpg'));

% convert RGB to gray
gI = rgb2gray(I);
[nrow, ncol] = size(gI);

% divide the image into 4-by-4 blocks
gI = mat2tiles((gI),[4,4]);

N = 4*4; % block size

% For each block, compute the horizontal gradient  
gI = reshape([gI{:}],4*4, []);
mask = fspecial('sobel');
g = imfilter(gI, mask);
g_bar = g./N;


g_bar = reshape(g_bar,nrow, ncol);

I'm new to Matlab so I'm not sure if my code is expressing the equation in the right way.

Can you please let me know if you think it is correct? as I'm not sure how to test the output!

asked 57 secs ago

user2833205

1

How to compute horizontal gradient value?