function a=invmodel(name,par)%INVMODEL calculates the parameters of the inverse camera model, which%can be used to correct measured image coordinates to correspond a simple%pinhole model.%%Usage:%   par2=invmodel(name,par)%%where%   name = string that is specific to the camera and the framegrabber.%          This string must be defined in configc.m%   par  = camera intrinsic parameters obtained using cacal.m (cacalw.m)%   par2 = camera intrinsic parameters for correcting coordinates%   Version 3.0  10-17-00%   Janne Heikkila, University of Oulu, Finlandsys=configc(name);NDX=sys(1); NDY=sys(2); Sx=sys(3); Sy=sys(4);Asp=par(1); Foc=par(2);Cpx=par(3); Cpy=par(4);Rad1=par(5); Rad2=par(6);Tan1=par(7); Tan2=par(8);[dx,dy]=meshgrid(-NDX/40:NDX/40:NDX+NDX/40,-NDY/40:NDY/40:NDY+NDY/40);cc=imcorr(name,par,[dx(:) dy(:)]);cx=(cc(:,1)-Cpx)/NDX*Sx/Asp;cy=(cc(:,2)-Cpy)/NDY*Sy;%cpx=Cpx/NDX*Sx/Asp;%cpy=Cpy/NDY*Sy;%xs=-cpx*0.95; xe=(Sx-cpx)*0.95;%ys=-cpy*0.95; ye=(Sy-cpy)*0.95;%px=Sx/40; py=Sy/40;%[cx,cy]=meshgrid(xs:px:xe,ye:-py:ys); cx=cx(:); cy=cy(:);r2=cx.*cx+cy.*cy;delta=Rad1*r2+Rad2*r2.*r2;Q=1+(4*Rad1*r2+6*Rad2*r2.*r2+8*Tan1*cy+8*Tan2*cx);dx=cx-(cx.*delta+2*Tan1*cx.*cy+Tan2*(r2+2*cx.*cx))./Q; dy=cy-(cy.*delta+Tan1*(r2+2*cy.*cy)+2*Tan2*cx.*cy)./Q; r2=dx.*dx+dy.*dy;  Tx=[dx.*r2 dx.*r2.*r2 2*dx.*dy r2+2*dx.*dx];Ty=[dy.*r2 dy.*r2.*r2 r2+2*dy.*dy 2*dx.*dy];T=[Tx;Ty];e=[cx-dx;cy-dy];a=pinv(T)*e;par=par(:);a=[par(1:4);a];