一个zernike矩的程序，问相关有关问题

一个zernike矩的程序，问相关问题
% _____OUTPUTS____________________________________________________________
% A_nm Zernike moments (row vector)
% zmlist keeps order and repetition information (Mx2 matrix)
% M = total # of moments
% cidx 1-D indices of retained unit circle region (vector)
% V_nm Zernike polynomials size of img (col vectors)
% to save memory, exclude this output term
%
% _____INPUTS_____________________________________________________________
% img row by col image of reals (matrix)
% n order (vector)
% starting from 0
% m repetition (integer)
%
% _____NOTES______________________________________________________________
% - for demo, call function without parameters
%
% zernike(img)
% computes moment of order 0 repetition 0 
% zernike(img,n)
% computes all moments of order specified in VECTOR n
% zernike(img,n,m)
% computes moment of VECTOR order n repetition m
% - |m|<=n and n-|m| even
% - img MUST first be normalized w.r.t. scale and translation
% i.e. centroid of image is at image center, and image
% has geometrical moment m00 = fixed number/scale
% - x,y follows raster scanning convention
% - rotation invariant in the magnitude, i.e. |A_nm|
% - to start from a particular order, specify a range in n, e.g. [4 5 6]
% - n=0 is useless for centered data as it is simply the center of mass


  是英文的注释，不太明白，想请各位大牛帮帮忙，帮助理解一下输入部分、输出部分的解释
  例如，输入格式为zernike(img,12,3) 是不是计算图像img的12阶zernike矩？如果是，理论上zernike的12阶矩应该有7个矩特征，为什么程序只有1个复数结果输出？
  是我毕业设计的内容，急切等待大家帮忙


------解决方案--------------------
这个不是很明显么。
输出的是12阶的第三个值。
泽尔尼克矩阵输出结果本身就是复数。