performance - Matlab execute function each cell Matrix with matrix and cell postion as arguments -

performance - Matlab execute function each cell Matrix with matrix and cell postion as arguments -

i need apply function each pixel of each image in set of ~400 images. function wrote (called customf) requires 3 arguments: matrix, , position of cell in matrix (m , n). position of pixel needed in order compute lbp (local binary pattern) requires values of surrounding pixels. customf(matrix, m, n) returns integer d 0 < d < 256, , store each value of d in matrix of same size image.

given set quite large, i'd code efficient possible, don't understand how utilize cellfun or arrayfun in such way.

or improve solution? (using nested for might inefficient?)

thanks!

can write customf in different way? instead of working on entire image each pixel (m, n), why don't give local patch required computing lbp of patch's central pixel?

for example, if customf needs @ pixels -/+ k away m, n compute response d @ m, n, may have

k = 5; localf = @( patch ) customf( patch, k+1, k+1 ); % assuming patch of size (2k+1)x(2k+1) % apply lbp image d = nlfilter( image, [2*k+1 2*k+1], localf );

note nlfilter zero-pads image in order obtain d same size image.

performance matlab matrix