3d interpolation
in [Matlab]
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From: Christian Reiss on 18 Jun 2010 18:27 HI all- I have a three-D array 120*100*100, I wish to interpolate the data along the third dimension so that the end result is a matrix 120*100*199. The third dimension is equally spaced. The ouput array would have interpolated values at points between each of the rows and columns and the original data should not be touched (a simple average of nearest neighbors would be fine). interp3 works across all elements as aa=interp3(X,3), and doesnt work. It would be better than what I am thinking (although i am brain dead at this moment) something like... for i= 1: length(U-1) Uaaa=(U(:,:,i)+U(:,:,i+1))/2; % not actually interp.. just element average U_new=cat(3, U(:,:,i), Uaaa, U(:,:,i+1));... end any help would be appreciated thanks chris
From: Bruno Luong on 19 Jun 2010 04:40 One way: % Data U=rand(2,3,10) Unew = permute(U,[3 1 2]); Unew = interp1(1:p,Unew,1:0.5:p); Unew = ipermute(Unew,[3 1 2]); % Bruno
From: Bruno Luong on 19 Jun 2010 04:47 Sorry I miss a line of code: > % Data > U=rand(2,3,10) > p = size(U,3) > Unew = permute(U,[3 1 2]); > Unew = interp1(1:p,Unew,1:0.5:p); > Unew = ipermute(Unew,[3 1 2]); > % Bruno
From: Christian Reiss on 21 Jun 2010 14:02 thanks bruno- This gives me some new thoughts, and at least a tempoary solution! cheers chris "Christian Reiss" <christian.reiss(a)noaa.gov> wrote in message <hvgrs8$45s$1(a)fred.mathworks.com>... > HI all- > > I have a three-D array 120*100*100, I wish to interpolate the data along the third dimension so that the end result is a matrix 120*100*199. The third dimension is equally spaced. The ouput array would have interpolated values at points between each of the rows and columns and the original data should not be touched (a simple average of nearest neighbors would be fine). > > interp3 works across all elements as aa=interp3(X,3), and doesnt work. > > It would be better than what I am thinking (although i am brain dead at this moment) > something like... > for i= 1: length(U-1) > > Uaaa=(U(:,:,i)+U(:,:,i+1))/2; % not actually interp.. just element average > > U_new=cat(3, U(:,:,i), Uaaa, U(:,:,i+1));... > end > > any help would be appreciated > > thanks > chris
From: Sean on 25 Jun 2010 09:27
"Christian Reiss" <christian.reiss(a)noaa.gov> wrote in message <hvgnbc$ohq$1(a)fred.mathworks.com>... > HI all- > > I have a three-D array 120*100*100, I wish to interpolate the data along the third dimension so that the end result is a matrix 120*100*199. The third dimension is equally spaced. The ouput array would have interpolated values at points between each of the rows and columns and the original data should not be touched (a simple average of nearest neighbors would be fine). > > interp3 works across all elements as aa=interp3(X,3), and doesnt work. > > It would be better than what I am thinking (although i am brain dead at this moment) > something like... > for i= 1: length(U-1) > > Uaaa=(U(:,:,i)+U(:,:,i+1))/2; % not actually interp.. just element average > > U_new=cat(3, U(:,:,i), Uaaa, U(:,:,i+1));... > end > > any help would be appreciated > > thanks > chris %A hint; if you're still looking. A = cat(3,ones(3),2*ones(3),3*ones(3)); [xold yold zold] = ndgrid(1:3,1:3,1:2:5); [xnew ynew znew] = ndgrid(1:3,1:3,1:5); griddata3(xold,yold,zold,A,xnew,ynew,znew) |