source: trunk/src/interp2_uvmat.m @ 728

Last change on this file since 728 was 653, checked in by sommeria, 11 years ago

bugs corrected for displaying small rgb color images.
proj_field/proj_plane imrpoved
browser changed to a more standard GUI presentaton

File size: 1.7 KB
Line 
1%'interp2_uvmat': linearly interpolate an image or scalar defined on a
2%regular grid        USE Matlab interp2 instead
3%--------------------------------------------------------------------
4%OUTPUT:
5% A_out: matrix of interpolated values at positions (XIMA,YIMA)
6%
7%INPUT:
8% A matrix (npy,npx) to interpolate
9%XIMA: matrix of non-integer x index values (npY,npX)
10%YIMA: matrix of non-integer y index values (npY,npX), (with the same size as XIMA)
11
12function A_out=interp2_uvmat(A,XIMA,YIMA)
13npx=size(A,2);
14npy=size(A,1);
15npX=size(XIMA,2);
16npY=size(XIMA,1);
17XIMA=reshape(XIMA,1,npX*npY)+0.5;%indices corresponding to XIMA, reshaped in a matlab vector
18YIMA=reshape(YIMA,1,npX*npY)+0.5;%indices corresponding to XIMA, reshaped in a matlab vector
19X_delta=XIMA-floor(XIMA);%distance to the closest integer value
20XIMA=floor(XIMA);%integer x index on the image
21Y_delta=YIMA-floor(YIMA);%distance to the closest integer value
22YIMA=floor(YIMA);%integer x index on the image       
23flagin=(XIMA>=1 & XIMA<=npx-1 & YIMA >=1 & YIMA<=npy-1);%flagin=1 inside the original image
24ind_in=find(flagin);%list of indices of XIndex for valid values of image indices (inside the original image)
25ind_out=find(~flagin);     
26vec_A=double(reshape(A(:,:,1),1,npx*npy));%reshape the original image as a Matlab image vector
27ICOMB=((XIMA-1)*npy+(npy+1-YIMA));%determine the indices in the image Matlab vector corresponding to XIMA and YIMA
28ICOMB=ICOMB(flagin);%selection of the valid indices
29X_delta=X_delta(ind_in);
30Y_delta=Y_delta(ind_in);
31A_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);
32A_out(ind_out)=zeros(size(ind_out));
33A_out=reshape(A_out,npY,npX);%interpolated image
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