Calculate the difference between adjacent pixels

Hello Team,

I have written this Matlab code to calculate the absolute difference between horizontally adjacent pixels.

imageArray = imread('index.jpg');

information = imfinfo('index.jpg')

for j = 1:1:information.Height - 1

for i = 1:1:information.Width - 2

D_hor(i,j) = abs(imageArray(i,j) - imageArray(i+1, j))

i = i +1

end

j = j+1

end

Once I started verifying the code using a simple Matrix, it displayed incorrect results.

Can you please help me?

Regards,

Answer 1

[jonas]

Try this instead

abs(diff(imageArray,1,2)) 

[Matlab Student]

It works, thanks you Jonas.

[jonas]

Happy to help!

[Matlab Student]

Hello again Jonas,

I have one more question please. The code should work fine even without the i=i+1 and j=j+1 statements cause the for loop statement controls the step by 1 "for i=1:1:information.height-1" (:1: should do the job).

Am I right?

imageArray = imread('index.jpg');

information = imfinfo('index.jpg')

for j = 1:1:information.Height - 1

for i = 1:1:information.Width - 2

abs(diff(imageArray,1,2))

end

end

[jonas]

Hi! You do not need the loops at all in this case. This is enough:

imageArray = imread('index.jpg');
information = imfinfo('index.jpg')
abs(diff(imageArray,1,2))

But yes, in general you are correct in that you do not need those lines at the end of for loops to adjust the looping variable.

[Matlab Student]

Thank you (flower)

[Matlab Student]

Good Morning Jonas,

May I ask how can I calculate the same in the vertical direction? I mean how to calculate the difference between vertically adjacent pixels?

Thanks in advance,

[jonas]

Just change the dimension argument from 2 to 1 :)

abs(diff(imageArray,1,1))
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