how to enter the weights in bilinear interpolation

here is the required code for wrapping an image using bilinear interpolation.how to calculate weights. Please help

function Iout=deform(Iin,T) % function Iout=deform(Iin,T) % Bilinear Interpolation Operation on 2D image I using Deformation Field T % Inputs: % Iin is of size nx x ny % T is of size nx x ny x 2 % T(:,:,1)=Bx, deformation along x/rows % T(:,:,2)=By, deformation along y/columns % Output: % Iout is of size nx x ny

% x,y indices nx=size(Iin,1); ny=size(Iin,2);

% Regular output grid [xout,yout]=ndgrid(1:nx,1:ny);

% Corresponding input pixels xin=xout+T(:,:,1); yin=yout+T(:,:,2);

% Nearest grid points xin0=floor(xin); yin0=floor(yin); xin1=xin0+1; yin1=yin0+1;

% check_xin0=(xin0<1)|(xin0>nx); check_yin0=(yin0<1)|(yin0>ny); check_xin1=(xin1<1)|(xin1>nx); check_yin1=(yin1<1)|(yin1>ny);

% Bilinear interpolation weights (fractions) tx=xin-xin0; ty=yin-yin0; w00=?; w01=?; w10=?; w11=?;

xin0=min(max(xin0,1),nx); yin0=min(max(yin0,1),ny); xin1=min(max(xin1,1),nx); yin1=min(max(yin1,1),ny);

% Interpolate I00=Iin(xin0+(yin0-1)*nx); I01=Iin(xin0+(yin1-1)*nx); I10=Iin(xin1+(yin0-1)*nx); I11=Iin(xin1+(yin1-1)*nx);

w00(check_xin0|check_yin0)=0; w01(check_xin0|check_yin1)=0; w10(check_xin1|check_yin0)=0; w11(check_xin1|check_yin1)=0;

Iout=$;

[Image Analyst]

See http://www.mathworks.com/matlabcentral/answers/13205-tutorial-how-to-format-your-question-with-markup