I need some help,(i.e) my image is 192x192, i need to divide it into 3x3,and from each 3x3 block,by taking center pixel value as threshold, i need to compare with other neighbouring 8 pixel values, if that value is less than threshld, put 0, else 1

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x=imread('192x192' image); g=mat2tiles(x,[3,3]); f=cellfun(..............)% i need ur help plzzzzzzz

Accepted Answer

Image Analyst
Image Analyst on 30 Aug 2016
No need to mess with the complication of cell arrays, simply index to subsample, resize, and then use "<" (less than operator).
data = randi(99, 192,192); % Sample data
[rows, columns] = size(data);
thresholds = data(2:3:end, 2:3:end); % Get centers of 3x3
% Make same size as data
thresholds = imresize(thresholds, [rows, columns], 'nearest');
% Apply threshold.
out = data > thresholds;

More Answers (1)

Teja Muppirala
Teja Muppirala on 30 Aug 2016
Edited: Teja Muppirala on 30 Aug 2016
If you have the Image Processing Toolbox, you can use BLOCKPROC , which is a general function for block processing.
x = randi(99, 192,192); % Sample data
out = blockproc(x, [3 3], @(I)I.data >= I.data(2,2)) % Is the block data greater than the middle element?

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