Sliding max window and its average for multi-dimensional arrays

Question

I have a 60 x 21 x 700 matrix, where the 60 x 21 represent a pressure output x number of frames. I want to find the 2 x

Answer 1

A moving average can be done with a simple convolution. It has to be 2D in your case, so:

A = [01 02 02 01 01
     02 01 01 02 02
     02 03 04 04 03
     01 02 06 10 05
     02 02 08 09 05];

B = [1 1;1 1] / 4 ; %// prepare moving average filter [2x2]

C = conv2(A,B,'valid') ; %// perform 2D moving average

Produces:

C =
    1.5     1.5     1.5     1.5
    2       2.25    2.75    2.75
    2       3.75    6       5.5
    1.75    4.5     8.25    7.25

Which is exactly the average of each of your [2x2] areas.