areaSigma = 1. _d 0/sqrt(localweight(i,j,bi,bj))
areaSigma = areaSigma * 0.85 _d 0
areaSigma = areaSigma * 1.2 _d 0
areaSigma = areaSigma * 1.1 _d 0
& 1. _d 0 / (areaSigma*areaSigma)
& areaSigma
_RL areaSigma