Mat2Cell error when splitting an image up into smaller images

Hello, i have a large Image (3200 x 14444 pixels). I want to split it into subimages. Im using mat2cell but Im getting the error as shown below.

blockSizeRow=512
blockSizeCol=256

function blockImages = splitImageIntoBlocks(image, blockSizeRow, blockSizeCol)
% blockSizeRow: Rows in block
% blockSizeCol: Columns in block
[nrows, ncols] = size(image);
% Calculate size of each block by rows and columns
nBlocksRow = floor(nrows / blockSizeRow);
nBlocksCol = floor(ncols / blockSizeCol);

rowDist = [blockSizeRow * ones(1, nBlocksRow-1), rem(nrows, nBlocksRow) + blockSizeRow];
colDist = [blockSizeCol * ones(1, nBlocksCol-1), rem(ncols, nBlocksCol) + blockSizeCol];
blockImages = mat2cell(image, rowDist, colDist); 

Error using mat2cell (line 89)
Input arguments, D1 through D2, must sum to each dimension of the input matrix size, [3200  14444].

[Walter Roberson]

Do I understand correctly that in the case of partial blocks that you want the last block to be larger to hold the extra, instead of wanting the last block to be smaller if needed? For example block size 512 and width 1500 you would want 512, 988 rather than 512, 512, 476?

[Jason]

Hi Walter, I'd rather the last block be smaller so I retain as many partial blocks of the same size as possible

[Walter Roberson]

Last block is mod(nrows, blockSizeRow) with nothing added. Just watch out for the case where the size is exactly divisible into blocks: mat2cell is happy to toss in a block of size 0 but you probably do not want those

Answer 1

[Walter Roberson]

function blockImages = splitImageIntoBlocks(image, blockSizeRow, blockSizeCol)
% blockSizeRow: Rows in block
% blockSizeCol: Columns in block
[nrows, ncols] = size(image);
% Calculate size of each block by rows and columns
nBlocksRow = floor(nrows / blockSizeRow);
nBlocksCol = floor(ncols / blockSizeCol);
rowDist = [blockSizeRow * ones(1, nBlocksRow), mod(nrows, nBlocksRow)];
colDist = [blockSizeCol * ones(1, nBlocksCol), mod(ncols, nBlocksCol)];
%check for case of file image divisible into blocks
if rowDist(end) == 0; rowDist(end) = []; end
if colDist(end) == 0; colDist(end) = []; end
blockImages = mat2cell(image, rowDist, colDist, size(image,3)); 

[Jason]

Thanks Walter