| jssylttc |
2012-04-23 19:23 |
如何从zernike矩中提取出zernike系数啊
下面这个函数大家都不会陌生,计算zernike函数值的,并根据此可以还原出图像来, BO^e.iB/ 我输入10阶的n、m,r,theta为38025*1向量,最后得到的z是29525*10阶的矩阵, ;tO (,^ 这个,跟我们用zygo干涉仪直接拟合出的36项zernike系数,有何关系呢? *&7Av7S 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? i9Qx{f88 ffd yDUzQ x@yF|8 I/ c*
? <Fi/! function z = zernfun(n,m,r,theta,nflag) K:mb$YJ& %ZERNFUN Zernike functions of order N and frequency M on the unit circle. J}BS/Tr}= % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N _|3n h;-m % and angular frequency M, evaluated at positions (R,THETA) on the UhNeY{6 % unit circle. N is a vector of positive integers (including 0), and a4?:suX$ % M is a vector with the same number of elements as N. Each element 6 LC*X % k of M must be a positive integer, with possible values M(k) = -N(k) YQ&Xd/z- % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, qvCl
mZ % and THETA is a vector of angles. R and THETA must have the same y 2bZo'Z % length. The output Z is a matrix with one column for every (N,M) DEIn:d % pair, and one row for every (R,THETA) pair. R4{2+q=0 % )
b?HK SqI % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike L0}"H
. % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), cJ&%XN % with delta(m,0) the Kronecker delta, is chosen so that the integral I_4'9 % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, tJc9R2 % and theta=0 to theta=2*pi) is unity. For the non-normalized ? r^+- % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. qjuX16o % =F6J%$ % The Zernike functions are an orthogonal basis on the unit circle. DJhi>!xJ % They are used in disciplines such as astronomy, optics, and RV-7y^[]^ % optometry to describe functions on a circular domain. -3A#a_fu % +h"RXwlBM % The following table lists the first 15 Zernike functions. |:C=j/f % V#zDYrp % n m Zernike function Normalization ygh*oVHO % -------------------------------------------------- X2~>Z^,
U % 0 0 1 1 Ygr1 S(= % 1 1 r * cos(theta) 2 U]O7RH % 1 -1 r * sin(theta) 2 s/8>(-H# % 2 -2 r^2 * cos(2*theta) sqrt(6) 7Q2"]f,$CQ % 2 0 (2*r^2 - 1) sqrt(3) L]cZPfI6 % 2 2 r^2 * sin(2*theta) sqrt(6) :beBiO % 3 -3 r^3 * cos(3*theta) sqrt(8) )=#QTiJ % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) vn7<>k>dx % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) Zj%l (OVq % 3 3 r^3 * sin(3*theta) sqrt(8) zmF_-Q`c % 4 -4 r^4 * cos(4*theta) sqrt(10) w`q):yXX % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) !q mnMY$ % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) 7YrX3Hx8 % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) D3N\$ D % 4 4 r^4 * sin(4*theta) sqrt(10) qdWsP9}q % -------------------------------------------------- ;vnG %
v[\'
M % Example 1: YLk/16r % yc?+L;fN % % Display the Zernike function Z(n=5,m=1) Cwl#(;@ % x = -1:0.01:1; lOYzo % [X,Y] = meshgrid(x,x); f
0D9Mp % [theta,r] = cart2pol(X,Y); LNPwb1) % idx = r<=1; \hoYQK j % z = nan(size(X)); C;QIp6"1 % z(idx) = zernfun(5,1,r(idx),theta(idx)); &N.D!7X % figure 2Ck'A0d % pcolor(x,x,z), shading interp x8+W9i0[1 % axis square, colorbar MIGcV9hf % title('Zernike function Z_5^1(r,\theta)') CvS}U% % BxVo>r % Example 2: ~RgO9p(dY % wGr5V! % % Display the first 10 Zernike functions T*e>_\Tx % x = -1:0.01:1; 5srj|'ja % [X,Y] = meshgrid(x,x); $)8b)Tb % [theta,r] = cart2pol(X,Y); U=QfInB % idx = r<=1; vau0Jn%=ck % z = nan(size(X)); {@ ygq-TZ % n = [0 1 1 2 2 2 3 3 3 3]; '7Q5"M'
% m = [0 -1 1 -2 0 2 -3 -1 1 3]; R-5EztmLae % Nplot = [4 10 12 16 18 20 22 24 26 28]; K=nW|^ % y = zernfun(n,m,r(idx),theta(idx)); 2j*;1 % figure('Units','normalized') JL.noV3q$ % for k = 1:10 I:?1(.kd2- % z(idx) = y(:,k); OiAP%7i9 % subplot(4,7,Nplot(k)) +X#JCLD % pcolor(x,x,z), shading interp tj7{[3~-[ % set(gca,'XTick',[],'YTick',[]) 0<(F
8 % axis square QU{|S.\ % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) 99)m d % end ay4E\=k % tj<a , l % See also ZERNPOL, ZERNFUN2. %an"cQ
] zI1-l9 o !}
~K'1" % Paul Fricker 11/13/2006 2vbm=~)$F N{rC#A3 & | |