2D moving sum of a matrix

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Jakob Sievers
Jakob Sievers 2020-8-16
评论： Jakob Sievers 2020-8-16
Hi there
How do I perform a moving sum within a matrix? I.e.: the result of each index will be the sum of all surrounding indexes, as defined by window lengths (with some edge effects, as with a regular moving sum).
I could definitely set up some basic loop function but I anticipate having to do this quite often and so I wish to find a smarter/faster solution. And I suspect that there definitely is a smarter solution. Like maybe using filter2 or something?
Thanks in advance for all help!
Cheers
Jakob
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KSSV
KSSV 2020-8-16
There is inbuilt function movsum, did you see that?

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采纳的回答

Bruno Luong
Bruno Luong 2020-8-16
编辑：Bruno Luong 2020-8-16
Assuming A is your array, w is the window size
% testexample
A=randi(10,5)
movsum(movsum(A,w,1),w,2)
% or
conv2(A, ones(w), 'same')
% or
filter2(ones(w), A, 'same')
  1 个评论
Jakob Sievers
Jakob Sievers 2020-8-16
Thank you so much for this. I knew there was a simple way to do this.
I ended up using fspecial to create a circular sum-filter instead of a basic square sum-filter:
filter=fspecial('disk',5)>0;

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更多回答（1 个）

Walter Roberson
Walter Roberson 2020-8-16
conv2(YourMatrix, ones(WindowHeight, WindowWidth))
You might want to add options such as 'valid' to control the size of output and the edge effects.

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