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

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

Answer 1

[Image Analyst]

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;

Answer 2

[Teja Muppirala]

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?