image block block dividing

sir i have a black and white(binary image) of size(i j) and i need to divide image into blocks of 3X3 size please help me in coding.

sir i used r=blkproc(BW,[3 3]); but it showing error like this

??? Index exceeds matrix dimensions.

Error in ==> blkproc>parse_inputs at 244 [fun,msg] = fcnchk(varargin{3},length(params));

Error in ==> blkproc at 62 [a, block, border, fun, params, padval] = parse_inputs(varargin{:});

Answer 1

[Walter Roberson]

There is no default value for the function. You need to provide at least 3 arguments for blkproc()

If you do not want overlapping blocks, and your images are exact multiples of 3 on each side, and you just want all of the blocks returned instead of doing something with them, then:

r = mat2cell(BW, 3 * ones(1,size(BW,1)/3), 3 * ones(1,size(BW,2)/3));

This will return a cell array of 3x3 arrays.

[javeed miyandad]

r = mat2cell(bw, 3 * ones(1,size(bw,1)/3), 3 * ones(1,size(bw,2)/3));

sir its showing eror like this

Warning: Size vector should be a row vector with integer elements.

Warning: Size vector should be a row vector with integer elements.

??? Error using ==> mat2cell

Input arguments, D1 through D2, must sum to each dimension of the input matrix size, [302 436].

[javeed miyandad]

sir my image is not exat multiples of 3 on each side wat to do

[Walter Roberson]

Well, what do you *want* to do about the part of your image that cannot be fit into the 3 x 3 non-overlapping blocks?

[javeed miyandad]

if that part is corner image then its ok leave that part or omit that part sir

[javeed miyandad]

if that part is corner image then its ok leave that part or omit that part sir

[javeed miyandad]

sir ,or is it possible to add additional pixels so that i can convert the image as multiple of 3 on each side ,

[Walter Roberson]

BW2 = zeros(3 * ceil(size(BW)/3));

BW2(1:size(BW,1),1:size(BW,2)) = BW;

BW = BW2;

[javeed miyandad]

thak you sir,

howto view indivisual blocks

i used imshow(r(:,:,1))

but it showing

??? Function 'real' is not defined for values of class 'cell'.

Error in ==> real at 15

[varargout{1:nargout}] = builtin('real', varargin{:});

Error in ==> imshow>ValidateCdata at 498

cdata = real(cdata);

Error in ==> imshow>ParseInputs at 378

cdata = ValidateCdata(cdata);

Error in ==> imshow at 85

[cdata, cdatamapping, clim, map, xdata, ydata, filename, ...

[Walter Roberson]

imshow(r{2,7}) %for example

[Soumya]

Sir I happened to see this answer,and

1) now i have a doubt that how the entire blocks of the image can be viewed like that of blkproc().

2)imshow(r{2,7}) ->what doest the two values 2 and seven refer to?