Finding the average of the neighbors of each pixel in an image

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I want to replace each pixel by the average of 3 x 3 neighbors using 4-connected neighbors (I4) and 8- connected neighbors (I8).

Answers (1)

Matt J
Matt J on 22 Sep 2021
mean4=conv2(image,[0 1 0; 1 1 1; 0 1 0]/5,'same');
mean8=conv2(image,ones(3)/9,'same');
  16 Comments
Image Analyst
Image Analyst on 18 Jul 2022
You have to specify which pixels to use in the average. That kernel basically specifies which of the 9 pixels in the 3x3 window to use in computing the average. You can specify whatever you want in your kernel. Like if you wanted to replace the center pixel by the average of the 4 on the corners, you'd do
kernel = [1,0,1; 0,0,0; 1,0,1] / 4; % Diagonals only.
blurredImage = conv2(double(grayImage), kernel, 'same');
% or, including the middle pixel:
kernel = [1,0,1; 0,1,0; 1,0,1] / 4; % Diagonals plus center pixel.
blurredImage = conv2(double(grayImage), kernel, 'same');

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