;----------------------------------------------------------------- ; pol_eaa.pro ; ; written by Andreas Reigber ;------------------------------------------------------------------ ; Calculates the polarimetric entropy/anisotropy/average alpha angle ; from the eigenvektors and eigenvalues of the coherency matrix. ; Attention: Coherency matrix means Pauli-base. If this is not the ; case, the results will be wrong. ; ; Usage: ; res = pol_eaa(ev,ew) ; ; ev = complex 3x3 matrix of eigenvectors ; ew = complex or float array of the three eigenvalues ; ; res = array containing: [entropy,alpha,anisotropy] ; ;------------------------------------------------------------------ ; This software has been released under the terms of the GNU Public ; license. See http://www.gnu.org/copyleft/gpl.html for details. ;------------------------------------------------------------------ function pol_eaa,ev,ew ew_a = abs(ew) pi = ew_a / total(ew_a) ent = total(-pi*alog(pi)/alog(3)) alp = acos(abs(ev[0,0]))*pi[0] + acos(abs(ev[0,1]))*pi[1] + acos(abs(ev[0,2]))*pi[2] ew_a = ew_a[reverse(sort(ew_a))] ani = (ew_a[1]-ew_a[2])/(ew_a[1]+ew_a[2]) return,[ent,alp,ani] end