Average Filter

Average filter performs image smoothing with integral image method.

Description

The advantage of this implementation in comparison to imfilter from Image Processing Toolbox is that the processing time is independent of window size. In practise it means that this implementation of mean filter is faster than imfilter whenever one of the window dimensions is bigger than 21 pixels.

• MATLAB release: MATLAB 6.5 (R13)

[Jan Motl]

Hi Jan,
thank you for your feedback. The biggest gain from the vectorised version is in calculation of the integral image - cumsum accelerated the whole function by 5%. And that is good.

[Jan Simon]

Although I like FOR loops, here a vectorized approach would be much more efficient, e.g.:
output = (t(1+m:rows+m, 1+n:columns+n) + t(1:rows, 1:columns) -
t(1+m:rows+m, 1:columns) - t(1:rows, 1+n:columns+n)) / winNum;

The documentation is very good: H1 line, exhaustive descritpion of inputs and outputs, "See also" line. I only miss a date and the author.
The inputs are check reliably.