[646] | 1 | %'interp2_uvmat': linearly interpolate an image or scalar defined on a regular grid |
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| 2 | %-------------------------------------------------------------------- |
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| 3 | %OUTPUT: |
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| 4 | % A_out: matrix of interpolated values at positions (XIMA,YIMA) |
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| 5 | % |
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| 6 | %INPUT: |
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[8] | 7 | % A matrix (npy,npx) to interpolate |
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| 8 | %XIMA: matrix of non-integer x index values (npY,npX) |
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| 9 | %YIMA: matrix of non-integer y index values (npY,npX), (with the same size as XIMA) |
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[646] | 10 | |
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[8] | 11 | function A_out=interp2_uvmat(A,XIMA,YIMA) |
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| 12 | npx=size(A,2); |
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| 13 | npy=size(A,1); |
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| 14 | npX=size(XIMA,2); |
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[646] | 15 | npY=size(XIMA,1); |
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[8] | 16 | XIMA=reshape(XIMA,1,npX*npY)+0.5;%indices corresponding to XIMA, reshaped in a matlab vector |
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| 17 | YIMA=reshape(YIMA,1,npX*npY)+0.5;%indices corresponding to XIMA, reshaped in a matlab vector |
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| 18 | X_delta=XIMA-floor(XIMA);%distance to the closest integer value |
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| 19 | XIMA=floor(XIMA);%integer x index on the image |
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| 20 | Y_delta=YIMA-floor(YIMA);%distance to the closest integer value |
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| 21 | YIMA=floor(YIMA);%integer x index on the image |
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| 22 | flagin=(XIMA>=1 & XIMA<=npx-1 & YIMA >=1 & YIMA<=npy-1);%flagin=1 inside the original image |
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| 23 | ind_in=find(flagin);%list of indices of XIndex for valid values of image indices (inside the original image) |
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| 24 | ind_out=find(~flagin); |
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| 25 | vec_A=double(reshape(A(:,:,1),1,npx*npy));%reshape the original image as a Matlab image vector |
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| 26 | ICOMB=((XIMA-1)*npy+(npy+1-YIMA));%determine the indices in the image Matlab vector corresponding to XIMA and YIMA |
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| 27 | ICOMB=ICOMB(flagin);%selection of the valid indices |
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| 28 | X_delta=X_delta(ind_in); |
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| 29 | Y_delta=Y_delta(ind_in); |
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| 30 | A_out(ind_in)=(1-Y_delta).*(1-X_delta).*vec_A(ICOMB)+Y_delta.*(1-X_delta).*vec_A(ICOMB-1)+X_delta.*(1-Y_delta).*vec_A(ICOMB+npy)+X_delta.*Y_delta.*vec_A(ICOMB+npy-1); |
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| 31 | A_out(ind_out)=zeros(size(ind_out)); |
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| 32 | A_out=reshape(A_out,npY,npX);%interpolated image |
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