how to divide image into 3x3 blocks? '9 parts'

i have one rgb image, i converted it to gray then to binary, did imfill, further i want to split that image into 9 blocks i.e 3x3 , please help me

[Jan]

Please show us, what you have tried so far and explain explicitly which problem occur.

Answer 1

[Matt J]

Using MAT2TILES

splitImage=mat2tiles(grayImage,[3,3]);

[nitesh patil]

i want to split complete image into 9 parts ,that is it,

[Matt J]

splitImage=mat2tiles(grayImage,ceil(size(grayImage)/3));

Answer 2

[Image Analyst]

See the FAQ for 2 different ways of doing it: http://matlab.wikia.com/wiki/FAQ#How_do_I_split_an_image_into_non-overlapping_blocks.3F

[Image Analyst]

Try this. It doesn't get much simpler than this:

grayImage = imread('cameraman.tif'); % Read in image.
% Figure out where to divide it.
[rows, columns, numberOfColorChannels] = size(grayImage);
r3 = int32(rows/3);
c3 = int32(columns/3);
% Extract the 9 images.
image1 = grayImage(1:r3, 1:c3);
image2 = grayImage(1:r3, c3+1:2*c3);
image3 = grayImage(1:r3, 2*c3+1:end);
image4 = grayImage(r3+1:2*r3, 1:c3);
image5 = grayImage(r3+1:2*r3, c3+1:2*c3);
image6 = grayImage(r3+1:2*r3, 2*c3+1:end);
image7 = grayImage(2*r3+1:end, 1:c3);
image8 = grayImage(2*r3+1:end, c3+1:2*c3);
image9 = grayImage(2*r3+1:end, 2*c3+1:end);

% Display the 9 images.
subplot(3,3,1);
imshow(image1);
subplot(3,3,2);
imshow(image2);
subplot(3,3,3);
imshow(image3);
subplot(3,3,4);
imshow(image4);
subplot(3,3,5);
imshow(image5);
subplot(3,3,6);
imshow(image6);
subplot(3,3,7);
imshow(image7);
subplot(3,3,8);
imshow(image8);
subplot(3,3,9);
imshow(image9);

[moahaimen talib]

hi sir i did your code i made it read 50 images from a dir but it only segmented the last one i need it to segment all 50 images how?

clc;
clear all;
close all;
tic
%Load current directory
myFolder = 'binary';
if ~isdir(myFolder)
errorMessage = sprintf('Error: The following folder does not exist:\n%s', myFolder);
uiwait(warndlg(errorMessage));
return;
end
filePattern = fullfile(myFolder, '*.jpg');
jpegFiles = dir(filePattern);

       resize=256;   

    if(ndims(jpegFiles)==3)
        jpegFiles=rgb2gray(jpegFiles);
        jpegFiles=jpegFiles(:,:,3);
    else
        jpegFiles=jpegFiles;
    end
    for k = 1:length(jpegFiles)
    % %      resize=256; 
    %  % resize
    %  

        baseFileName = jpegFiles(k).name;
        fullFileName = fullfile(myFolder, baseFileName);
        fprintf(1, 'Now reading %s\n', fullFileName);
      imageArray = imread(fullFileName);

% Figure out where to divide it.
[rows, columns, numberOfColorChannels] = size(imageArray);
r3 = int32(rows/3);
c3 = int32(columns/3);
% Extract the 9 images.
image1 = imageArray(1:r3, 1:c3);
image2 = imageArray(1:r3, c3+1:2*c3);
image3 = imageArray(1:r3, 2*c3+1:end);
image4 = imageArray(r3+1:2*r3, 1:c3);
image5 = imageArray(r3+1:2*r3, c3+1:2*c3);
image6 = imageArray(r3+1:2*r3, 2*c3+1:end);
image7 = imageArray(2*r3+1:end, 1:c3);
image8 = imageArray(2*r3+1:end, c3+1:2*c3);
image9 = imageArray(2*r3+1:end, 2*c3+1:end);
% Display the 9 images.
subplot(3,3,1);
imshow(image1);
subplot(3,3,2);
imshow(image2);
subplot(3,3,3);
imshow(image3);
subplot(3,3,4);
imshow(image4);
subplot(3,3,5);
imshow(image5);
subplot(3,3,6);
imshow(image6);
subplot(3,3,7);
imshow(image7);
subplot(3,3,8);
imshow(image8);
subplot(3,3,9);
imshow(image9);

end

but i tried to make the loop variable like this

image1(k) = imageArray(1:r3, 1:c3);
image2(k) = imageArray(1:r3, c3+1:2*c3);
image3(k) = imageArray(1:r3, 2*c3+1:end);
image4(k) = imageArray(r3+1:2*r3, 1:c3);
image5(k) = imageArray(r3+1:2*r3, c3+1:2*c3);
image6(k) = imageArray(r3+1:2*r3, 2*c3+1:end);
image7 (k)= imageArray(2*r3+1:end, 1:c3);
image8(k) = imageArray(2*r3+1:end, c3+1:2*c3);
image9 (k)= imageArray(2*r3+1:end, 2*c3+1:end);

but this error message appeared 

Subscripted assignment dimension mismatch.

Error in rgn (line 43)
image1(k) = imageArray(1:r3, 1:c3);

thank you

[moahaimen talib]

i think i solved the problem by putting

figure(k);
subplot(3,3,1);
imshow(image1);
subplot(3,3,2);
imshow(image2);
subplot(3,3,3);
imshow(image3);
subplot(3,3,4);
imshow(image4);
subplot(3,3,5);
imshow(image5);
subplot(3,3,6);
imshow(image6);
subplot(3,3,7);
imshow(image7);
subplot(3,3,8);
imshow(image8);
subplot(3,3,9);
imshow(image9);
--------------------------------------------------------------

now it shows all segmented images but how can i store each part and extract features for them and store them in good dataset for classification?

-------------------------------------------------------------------

i could make this instruction it will extract features for image1 for all 20 images but i need it for all 9 parts(image1...image9)

% Extract the 9 images.
image1 = imageArray(1:r3, 1:c3);
GLCM = graycomatrix(image1,'Offset',[0 2]);
Resultstats = graycoprops(GLCM,{'energy','Homogeneity'})
image2 = imageArray(1:r3, c3+1:2*c3);
image3 = imageArray(1:r3, 2*c3+1:end);
image4 = imageArray(r3+1:2*r3, 1:c3);
image5 = imageArray(r3+1:2*r3, c3+1:2*c3);
image6 = imageArray(r3+1:2*r3, 2*c3+1:end);
image7 = imageArray(2*r3+1:end, 1:c3);
image8 = imageArray(2*r3+1:end, c3+1:2*c3);
image9 = imageArray(2*r3+1:end, 2*c3+1:end);

[Walter Roberson]

atiqah ghaffar comments to Image Analyst

Thank you. This helps a lot.