| 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, Ti>}To}B5 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, BJ{?S{"6%G 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? j_S3<wEJ 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? 3A\Z]L \p!m/2 <]*Jhnx/ E CPSE{ ZHCrKp function z = zernfun(n,m,r,theta,nflag) 7?\r9bD %ZERNFUN Zernike functions of order N and frequency M on the unit circle. <}F(G-kV6 % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N gl!ht@;>ak % and angular frequency M, evaluated at positions (R,THETA) on the \jAI~|3 % unit circle. N is a vector of positive integers (including 0), and ;Hb"SB % M is a vector with the same number of elements as N. Each element T#HF!GH] % k of M must be a positive integer, with possible values M(k) = -N(k) \\35}
9 % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, & d* bQv$ % and THETA is a vector of angles. R and THETA must have the same ?<^^.Si % length. The output Z is a matrix with one column for every (N,M) *p|->p6,u % pair, and one row for every (R,THETA) pair. m<!CF3g % EF;B)y= % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike Wj, {lJ, % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), |*L/
m0'L % with delta(m,0) the Kronecker delta, is chosen so that the integral ,2P/[ : % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, "@rHGxK % and theta=0 to theta=2*pi) is unity. For the non-normalized
JY_!G % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. MPLeqk$; % 2~hQ % The Zernike functions are an orthogonal basis on the unit circle. 1/SB[[ g % They are used in disciplines such as astronomy, optics, and "WH
&BhQYD % optometry to describe functions on a circular domain. `0-i>> % V=c?V/pl % The following table lists the first 15 Zernike functions. epcvwM/A % |V^f}5gd % n m Zernike function Normalization p$<){,R % -------------------------------------------------- tR_DN % 0 0 1 1 &09G9G snQ % 1 1 r * cos(theta) 2 |@hyGu-H+ % 1 -1 r * sin(theta) 2 4 &0MB>m % 2 -2 r^2 * cos(2*theta) sqrt(6) E&Sr+D aPD % 2 0 (2*r^2 - 1) sqrt(3) B0^:nYko % 2 2 r^2 * sin(2*theta) sqrt(6) ~O
4@b/!4 % 3 -3 r^3 * cos(3*theta) sqrt(8) HN<e)E38 % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) Kc+9n%sp % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) 8an_s%,AW % 3 3 r^3 * sin(3*theta) sqrt(8) ZQmg;L&7 % 4 -4 r^4 * cos(4*theta) sqrt(10) fLV@~T| % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) y/+y |.Xg % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) {wD "|K % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) NSQ)lSW,; % 4 4 r^4 * sin(4*theta) sqrt(10) z0T6a15f!P % -------------------------------------------------- s*vtCdrE.
% ryTtGx%a % Example 1: {3 >`k.w % ,Uy~O(Ft % % Display the Zernike function Z(n=5,m=1) =HMuAUa. % x = -1:0.01:1; 6>h"Lsww % [X,Y] = meshgrid(x,x); ^;@!\Rc % [theta,r] = cart2pol(X,Y); O\ w-hk % idx = r<=1; d/E0opv % z = nan(size(X)); _;-b ZH % z(idx) = zernfun(5,1,r(idx),theta(idx)); VGOdJ|2]Wr % figure &CfzhIi*! % pcolor(x,x,z), shading interp &pAmFe % axis square, colorbar 'JAe=K
H % title('Zernike function Z_5^1(r,\theta)') `U{#; % >9[wjB2?} % Example 2: ^{-Z3Yxd % YwJ<0;:+hS % % Display the first 10 Zernike functions 5=;'LWXCJ % x = -1:0.01:1; 5gwEr170 % [X,Y] = meshgrid(x,x); RR>G}u9np % [theta,r] = cart2pol(X,Y); Sbj{) % idx = r<=1; D
\boF+^ % z = nan(size(X)); !1P<A1K % n = [0 1 1 2 2 2 3 3 3 3]; Qq\hD@Z| % m = [0 -1 1 -2 0 2 -3 -1 1 3]; EtDzmpJR> % Nplot = [4 10 12 16 18 20 22 24 26 28]; ?#L5V'ZZ* % y = zernfun(n,m,r(idx),theta(idx)); [8[`V)b % figure('Units','normalized') &y ~GTEP % for k = 1:10 &tw{d DD6 % z(idx) = y(:,k); ['I5(M@ % subplot(4,7,Nplot(k)) ak(P<OC- % pcolor(x,x,z), shading interp ts=+k/Z % set(gca,'XTick',[],'YTick',[]) NaeG)u#+ % axis square >F/5`=/'h % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) )lVplAhZD % end !3o]mBH8 % ~uJO6C6A % See also ZERNPOL, ZERNFUN2. m_UzmWF 5I5#LQv0 ))uki*UNK % Paul Fricker 11/13/2006 1i
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\Qz _\AT_Zmy {-s7_\|p( % Check and prepare the inputs: E\~!E20^ % ----------------------------- 5Veybchy " if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) }vQY+O error('zernfun:NMvectors','N and M must be vectors.') 3yM!BTlX end !:|D[1m mQ:5(]v y?V#LW[^E if length(n)~=length(m) m# I error('zernfun:NMlength','N and M must be the same length.') QBTjiaYGa' end C-VkXk `wLMJ,@f. 5~xv"S(E} n = n(:); +p &$`( m = m(:); t%30B^Ii%K if any(mod(n-m,2)) }I#,o!)Vd error('zernfun:NMmultiplesof2', ... v ce1'aW 'All N and M must differ by multiples of 2 (including 0).') y3mJO[U0 a end 1.q
a//'RW J ?H|" U("m}^ if any(m>n) YDiru error('zernfun:MlessthanN', ... %2rUJaOgy$ 'Each M must be less than or equal to its corresponding N.') _6MNEoy? end I$1~;!< <,(Ww WJw
%[_W if any( r>1 | r<0 ) 98t|G5 error('zernfun:Rlessthan1','All R must be between 0 and 1.') qvN 5[rb end A*+KlhT
SR&'38UCe m*H6\on: if ( ~any(size(r)==1) ) || ( ~any(size(theta)==1) ) ;NrU|g/ksX error('zernfun:RTHvector','R and THETA must be vectors.') e{`DvfY21 end W8s/" 7D wf0Re` |%7OI#t^ r = r(:); 9y5nG theta = theta(:); ^[-3qi length_r = length(r); J l9w/T if length_r~=length(theta) /?
HLEX error('zernfun:RTHlength', ... 1N\-Ku 'The number of R- and THETA-values must be equal.') <LOas$
end `1)n2<B )l*6zn`z zrCQEQq % Check normalization: +#0,2wR# % -------------------- 'P<T,:z? if nargin==5 && ischar(nflag) WG.J-2#3 isnorm = strcmpi(nflag,'norm'); Zk75GC if ~isnorm :ODG]-QF error('zernfun:normalization','Unrecognized normalization flag.') F5;x>;r end $sR-J'EE! else 9x9~u8j isnorm = false; !Typ_Cs end XveG#oyiU %y}l^P5z k=qb YGK %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Y'%k
G5nF % Compute the Zernike Polynomials zWEt< `1M %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% b py576GwA &nEQ | |