function Idata=ftoa(tdata,wvdata);

global weight tdatatrue tdataret

size(tdata)
tdataret=[tdata]
error=[tdatatrue- tdata]


ln=length(wvdata);
kn=length(tdata);

for l=1:ln
     for k=1:kn

        
    B(l,k)=planck(wvdata(l),tdata(k));
    end
end



% calculate BTOA

for l=1:ln
Idata(l)=0;

for k=1:kn

    Idata(l)=Idata(l)+weight(l,k)*B(l,k);
end

end