Convert pixel subscripts to block subscripts
Create a small sample image as a 5-by-7 matrix of zeros. Here is an illustration of the small sample image, with the pixel coordinates of the four corners provided.
Create a blocked image from the sample image, specifying a 2-by-2 block size. To create this blocked image, use
blockedImage in write mode.
bim = blockedImage(,[5 7],[2 2],uint8(0),"Mode",'w');
Here is an illustration of the blocked image overlaid on the original image. It is divided into 2-by-2 blocks. In the diagram, each block contains it's block coordinates.
To determine which block contains a particular pixel, convert the pixel subscripts into block subscripts by using the sub2
blocksub function. By default, if the image is a multiresolution image, then sub2
blocksub uses pixel coordinates from coarsest level, although you can specify any level. Since the sample image has only one resolution level, sub2
blocksub converts level 1.
[blocksub] = sub2blocksub(bim,[2 3])
blocksub = 1×2 1 2
blocksub— Subscripts of block that contains pixel
Subscripts of the block that contains the pixel, returned as a K-by-N integer-valued matrix, for an N-dimensional blocked image. K is the number of coordinates.