Matrix Subtraction by taking mean of same matrix

Question

Preet Lal 2021-11-16

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1588419-matrix-subtraction-by-taking-mean-of-same-matrix

编辑： Matt J 2021-11-17

采纳的回答： Matt J

Data.mat

在 MATLAB Online 中打开

I want to subtract of data which is of 413 X 264 and from taking a mean of same data with 45x45 matrix

My code is

winSz = [45,45];   % window size [width (x), height (y)]
[m, n] = size(HH_lin_0p2km);
winX0 = 1:winSz(1):n-winSz(1)+1;   % starting index of x-values for each window
winY0 = 1:winSz(2):m-winSz(2)+1;   % starting index of y-values for each window
xWin = 0:winSz(1)-1;
yWin = 0:winSz(2)-1; 
for i = 1:size(HH_C,1)
    for j = 1:size(HH_C,2)
        HH_C = HH_lin_0p2km(winY0(i)+yWin, winX0(j)+xWin)-nanmean(HH_lin_0p2km(winY0(i)+yWin, winX0(j)+xWin),'all');
        HV_C = HV_lin_0p2km(winY0(i)+yWin, winX0(j)+xWin)-nanmean(HV_lin_0p2km(winY0(i)+yWin, winX0(j)+xWin),'all');
    end
end

And I am getting error as:

I am looking for output in 413x264 MATRIX

ndex exceeds the number of array elements. Index must not exceed 5.
Error in Soil_Moisture_Estimation (line 492)
        HH_C = HH_lin_0p2km(winY0(i)+yWin, winX0(j)+xWin)-nanmean(HH_lin_0p2km(winY0(i)+yWin, winX0(j)+xWin),'all');

Any one please help

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Answer 1

Matt J 2021-11-16

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1588419-matrix-subtraction-by-taking-mean-of-same-matrix#answer_833184

编辑：Matt J 2021-11-16

在 MATLAB Online 中打开

It would be faster to use sepblockfun from the File Exchange,

https://www.mathworks.com/matlabcentral/fileexchange/48089-separable-block-wise-operations

HH_C = process(HH_lin_0p2km);
HV_C = process(HV_lin_0p2km);
function out=process(H)
 winSz = [45,45];   % window size [width (x), height (y)]
 [m, n] = size(H);
 mm=ceil(winSz(1)/m)*m;
 nn=ceil(winSz(2)/n)*n;
 if mm*nn>m*n, H(mm,nn)=0; end
 
 nanmap=isnan(H);
 H(nanmap)=0;
 
 Means=sepblockfun(H,winSz,'sum')./sepblockfun(nanmap,winSz,'sum');
 
 out=H-repelem(Means,winSz); 
 
 out(nanmap)=nan;
 out=out(1:m,1:n);
end

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Preet Lal 2021-11-17

编辑：Preet Lal 2021-11-17

What's process here?

It's not working

Matt J 2021-11-17

编辑：Matt J 2021-11-17

在 MATLAB Online 中打开

How about the following modified version? I've run it on a 2x2 winSz as a test.

winSz=[2,2];
H=randi(4,4)
H = 4×4
     3     2     4     3
     1     3     2     1
     3     4     1     3
     4     3     3     3
[H_C,blockMeans] = process(H,winSz)
H_C = 4×4
    0.7500   -0.2500    1.5000    0.5000
   -1.2500    0.7500   -0.5000   -1.5000
   -0.5000    0.5000   -1.5000    0.5000
    0.5000   -0.5000    0.5000    0.5000
blockMeans = 4×4
    2.2500    2.2500    2.5000    2.5000
    2.2500    2.2500    2.5000    2.5000
    3.5000    3.5000    2.5000    2.5000
    3.5000    3.5000    2.5000    2.5000
function [out,Means]=process(H,winSz)
 [m, n] = size(H);
 mm=ceil(winSz(1)/m)*m;
 nn=ceil(winSz(2)/n)*n;
 if mm*nn>m*n, H(mm,nn)=0; end
 
 nanmap=isnan(H);
 H(nanmap)=0;
 
 Means=sepblockfun(H,winSz,'sum')./sepblockfun(~nanmap,winSz,'sum');
 Means=repelem(Means,winSz(1),winSz(2));
 
 
 out=H-Means; 
 
 out(nanmap)=nan;
 out=out(1:m,1:n);
end