i've divided the image into non-overlapping blocks and i want to calculate the mean of every block...

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angel
angel 2013-2-14
after calculating the mean i;ve to store it in array corresponding to their block number
plz tell me how to do?
Mean=[];
for row = 1 : blockSizeR : rows
for col = 1 : blockSizeC : columns
row1 = row;
row2 = row1 + blockSizeR - 1;
row2 = min(rows, row2);
col1 = col;
col2 = col1 + blockSizeC - 1;
col2 = min(columns, col2);
oneBlock = grayImage(row1:row2, col1:col2);
m=mean(mean(oneBlock));
M=m;
Mean=[Mean;M];
disp(Mean);
end
end
the above code shows only the mean value... but i want that it also shows the block number corresponding to the mean value...
plz rectify or modify the above code in order to do so.

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采纳的回答

Image Analyst
Image Analyst 2013-2-14
Not sure how you want to define block number but how about:
blockNumber = 1;
for row = 1 : blockSizeR : rows
for col = 1 : blockSizeC : columns
row1 = row;
row2 = row1 + blockSizeR - 1;
row2 = min(rows, row2);
col1 = col;
col2 = col1 + blockSizeC - 1;
col2 = min(columns, col2);
oneBlock = grayImage(row1:row2, col1:col2);
Mean(blockNumber) = mean2(oneBlock);
fprintf('The mean for block #%d = $f', ...
blockNumber, Mean(blockNumber));
blockNumber = blockNumber + 1;
end
end
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更多回答（2 个）

Abbas Cheddad
Abbas Cheddad 2013-2-14
Hi there,
You could do the following:
%%%%%%%%%%%%%
fun = @(block_struct) mean2(block_struct.data);
I2 = blockproc(A,[8 8],fun);
Block_Mean(:,1)=reshape(I2,[1 size(I2,1)*size(I2,2)]);
Block_Mean(:,2)=1:length(Block_Mean);
%%%%%%%%%%%%%%
Where "A" denotes your image and [8 8] is the size of the block of your choice. This will result in "Block_Mean" which holds the mean intensity and the corresponding block number.
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angel
angel 2013-2-14
@ Abbas: ya sir but block_proc returns single image after processing all the blocks..i've given the code above i have modified it as the image anaylst told me... i m trying to applying the sort function but not stricking to me how to apply
Abbas Cheddad
Abbas Cheddad 2013-2-14
Block_proc returns a single image with the same size as "A" if you use the documented code as in:
fun = @(block_struct) ...
mean2(block_struct.data) * ones(size(block_struct.data));
But in the code I have given you, each pixel in "I2" corresponds to the mean of a single block.
Anyhow, since what you have in hand works for you then happy days!

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Jan
Jan 2013-2-14
The fast C-MEX function FEX: BlockMean performs this operation.
R = BlockMean(img, blockSizeR, blockSizeC);
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