MATLAB: Create a mosaic using average color of block given image

average color of blockimage editing

I am required to read an image and generate an 8×8 mosaic using the average color of each block. This is my work so far, however the output is black and white. I need help to get the colors. Thank you.
smashpic = imread('PA6_smashing.png');
myfun = @(block_struct) mean2(block_struct.data) *...
ones(size(block_struct.data),class(block_struct.data));
mosaic = blockproc(smashpic,[8 8],myfun);
imshow(mosaic);

Best Answer

Hi,
I am assuming you want to get the average of color of each block for each component separately. In your function "myfun" by using "mean2()" you get the mean of the entire block as a single value which is then used for R,G and B values.
One way to get the mosaic in color would be to calculate the average for each color of the block separately and then combine them using the "cat" function. Here is an example :
smashpic = imread('peppers.png');
myfun = @(block_struct) cat(3,mean2(block_struct.data(:,:,1))*ones(block_struct.blockSize,class(block_struct.data))...
    ,mean2(block_struct.data(:,:,2))*ones(block_struct.blockSize,class(block_struct.data))...
    ,mean2(block_struct.data(:,:,3))*ones(block_struct.blockSize,class(block_struct.data)));
%myfun = @(block_struct) mean2(block_struct.data) *...
%ones(size(block_struct.data),class(block_struct.data)); %resulting image is black and white
mosaic = blockproc(smashpic,[8 8],myfun);
imshow(mosaic);
Hope this helps
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