|Image Processing Toolbox User's Guide|
The toolbox provides functions that you can use to process sliding neighborhoods or distinct blocks as columns. This approach is useful for operations that MATLAB performs columnwise; in many cases, column processing can reduce the execution time required to process an image.
For example, suppose the operation you are performing involves computing the mean of each block. This computation is much faster if you first rearrange the blocks into columns, because you can compute the mean of every column with a single call to the
mean function, rather than calling
mean for each block individually.
You can use the
colfilt function to implement column processing. This function
© 1994-2005 The MathWorks, Inc.