Function File: B = blockproc (A, [m,n], fun)

Function File: B = blockproc (A, [m,n], fun, …)

Function File: B = blockproc (A, [m,n], [mborder,nborder], fun, …)

Function File: B = blockproc (A, 'indexed', …)

Processes image in blocks using user-supplied function.

B=blockproc(A,[m,n],fun) divides image A in m-by-n blocks, and passes them to user-supplied function fun, which result is concatenated to build returning matrix B. If padding is needed to build m-by-n, it is added at the bottom and right borders of the image. 0 is used as a padding value.

B=blockproc(A,[m,n],fun, …) behaves as described above but passes extra parameters to function fun.

B=blockproc(A,[m,n],[mborder,nborder],fun, …) behaves as described but uses blocks which overlap with neighbour blocks. Overlapping dimensions are mborder vertically and nborder horizontally. This doesn’t change the number of blocks in an image (which depends only on size(A) and [m,n]). Adding a border requires extra padding on all edges of the image. 0 is used as a padding value.

B=blockproc(A,'indexed', …) assumes that A is an indexed image, so it pads the image using proper value: 0 for uint8 and uint16 images and 1 for double images. Keep in mind that if ’indexed’ is not specified padding is always done using 0.

See also: colfilt,inline,bestblk.

Demonstration 1

 blockproc (eye (6), [2, 2], @(x) any (x(:)))
 # Returns a 3-by-3 diagonal

ans =

  1  0  0
  0  1  0
  0  0  1

Package: image