bwpack() - Image Processing

BWP = bwpack(BW) packs the uint8 binary
image BW into the uint32 array BWP,
which is known as a packed binary image. Because
each 8-bit pixel value in the binary image has only two possible values, 1 and 0, bwpack can
map each pixel to a single bit in the packed output image.bwpack processes the image pixels by column,
mapping groups of 32 pixels into the bits of a uint32 value.
The first pixel in the first row corresponds to the least significant
bit of the first uint32 element of the output array.
The first pixel in the 32nd input row corresponds to the most significant
bit of this same element. The first pixel of the 33rd row corresponds
to the least significant bit of the second output element, and so
on. If BW is M-by-N,
then BWP is ceil(M/32)-by-N.
This figure illustrates how bwpack maps the pixels
in a binary image to the bits in a packed binary image.
Binary image packing is used to accelerate some binary morphological
operations, such as dilation and erosion. If the input to imdilate or imerode is
a packed binary image, the functions use a specialized routine to
perform the operation faster.Use bwunpack to unpack packed binary images.Code Generation support:
Yes.MATLAB Function Block support:
Yes.

Syntax

BWP = bwpack(BW)

Example

BW = imread('text.png');
BWp = bwpack(BW);
BWp_dilated = imdilate(BWp,ones(3,3),'ispacked');
BW_dilated = bwunpack(BWp_dilated, size(BW,1));

Output / Return Value

Limitations

Alternatives / See Also

Reference