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, +FAj30 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, a{.q/Tbt 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? [orL.D] 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? 6y~F'/ww z}B39L xhOoZ-
r5Tdp)S n{i,`oQ" function z = zernfun(n,m,r,theta,nflag) naW!b&: %ZERNFUN Zernike functions of order N and frequency M on the unit circle. I{jvUYrKH % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N #,u|*O: % and angular frequency M, evaluated at positions (R,THETA) on the 8lL|j % unit circle. N is a vector of positive integers (including 0), and F,{mF2U*$ % M is a vector with the same number of elements as N. Each element [IQ|c?DxpL % k of M must be a positive integer, with possible values M(k) = -N(k) hd u2?v@ % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, :Ys~Lt54 % and THETA is a vector of angles. R and THETA must have the same kQ}n~Hn % length. The output Z is a matrix with one column for every (N,M) {X&lgj % pair, and one row for every (R,THETA) pair. 18!y7
_cFT % i*Ldec^ % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike 4]uj+J % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), AoeRoqg % with delta(m,0) the Kronecker delta, is chosen so that the integral m$kQbPlatN % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, b.@a,:" % and theta=0 to theta=2*pi) is unity. For the non-normalized acR|X@\3 % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. b1KtSRLV % e[fOm0^.c % The Zernike functions are an orthogonal basis on the unit circle. PmRvjSIG % They are used in disciplines such as astronomy, optics, and XS [L-NHG % optometry to describe functions on a circular domain. P}Kgh7)3 % Zn'tNt/ % The following table lists the first 15 Zernike functions. w_xca( % odsFgh % n m Zernike function Normalization sa(.Anmlj % -------------------------------------------------- 6JDHwV % 0 0 1 1 LmePJ % 1 1 r * cos(theta) 2 DS<1"4 b| % 1 -1 r * sin(theta) 2 {K]5[bMT % 2 -2 r^2 * cos(2*theta) sqrt(6) NEIkG>\7q % 2 0 (2*r^2 - 1) sqrt(3) 6(Pan% % 2 2 r^2 * sin(2*theta) sqrt(6) ^ RA'E@" % 3 -3 r^3 * cos(3*theta) sqrt(8) 15\m.Ix % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) GWnIy6TH l % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) 6!ve6ZB[p % 3 3 r^3 * sin(3*theta) sqrt(8) pn
gto % 4 -4 r^4 * cos(4*theta) sqrt(10) o@Oz
a % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) DPTk5o[ % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) _`|1B$@x % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) [|DKBJ % 4 4 r^4 * sin(4*theta) sqrt(10) .B#
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% -------------------------------------------------- VThr]$2Y % tcuwGs>_ % Example 1: ff\~`n~WZ % t'rN7.d % % Display the Zernike function Z(n=5,m=1) ["Ltqgx % x = -1:0.01:1; \^c4v\s<o# % [X,Y] = meshgrid(x,x); //q(v,D%Q % [theta,r] = cart2pol(X,Y); L>1hiD& % idx = r<=1; i2~uhGJ % z = nan(size(X)); amu;grH % z(idx) = zernfun(5,1,r(idx),theta(idx)); &riGzU] % figure QPJ\Iu@D$ % pcolor(x,x,z), shading interp pk/#RUfT+ % axis square, colorbar ]:<!( % title('Zernike function Z_5^1(r,\theta)') |h>PUt@LL % fFjpQ~0 % Example 2: 5ilGWkb`'X % 6pt_cpbR % % Display the first 10 Zernike functions QJGGce % x = -1:0.01:1; $KiCs]I+ % [X,Y] = meshgrid(x,x); ,c p2Fac % [theta,r] = cart2pol(X,Y); Y'iX
% idx = r<=1; GXtMX ha, % z = nan(size(X)); +I3jI < % n = [0 1 1 2 2 2 3 3 3 3]; 0bg"Q4 % m = [0 -1 1 -2 0 2 -3 -1 1 3]; K}~$h,n % Nplot = [4 10 12 16 18 20 22 24 26 28]; Ps!MpdcL3 % y = zernfun(n,m,r(idx),theta(idx)); B0fOAP1 % figure('Units','normalized') +$dJA % for k = 1:10 t]yxLl\ % z(idx) = y(:,k); CLR1CGnn7 % subplot(4,7,Nplot(k)) ,N.8 % pcolor(x,x,z), shading interp =}^NyLE? % set(gca,'XTick',[],'YTick',[]) 3S0.sU~_U % axis square I"07x'Ahq3 % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) 2Je$SE8 % end l!mbpFt % Ys"wG B> % See also ZERNPOL, ZERNFUN2. BG>Y[u\N 22`^Rsb,6L Xz+%Ym % Paul Fricker 11/13/2006 RLmOg{L [{znwK@ 3nq?Y8yac ejROJXB CdolZW-!" % Check and prepare the inputs: DXFu9RE\{ % ----------------------------- |3*9+4]a if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) f-ltV<C_ error('zernfun:NMvectors','N and M must be vectors.') gq+SM
i= end }u Y2-l
*LT~:Gs# 067c/c if length(n)~=length(m) "s2_X+4oY error('zernfun:NMlength','N and M must be the same length.') /sE,2X*BT end eA/n.V$z Av X1* (!~cOx
n = n(:); hnnB4]c m = m(:); mxa~JAlN_ if any(mod(n-m,2)) vwCQvt error('zernfun:NMmultiplesof2', ... *FS8]!Qg 'All N and M must differ by multiples of 2 (including 0).') @KN+)q P end !NXjax\r -9Q(3$} B=_w9iVN if any(m>n) ;Rrh$Ag error('zernfun:MlessthanN', ... IkrB} 'Each M must be less than or equal to its corresponding N.') YW}$e W* end -;""l{ i2F7O"f. ewDYu=`* if any( r>1 | r<0 ) dbp\tWaW error('zernfun:Rlessthan1','All R must be between 0 and 1.')
!`69.v end XlmX3RU L\:|95Yq /<LZt<K if ( ~any(size(r)==1) ) || ( ~any(size(theta)==1) ) !8{VLg error('zernfun:RTHvector','R and THETA must be vectors.') TOwd+]B end &i#$ia r LUOjaX (jc@8@Wo. r = r(:); lZFu|( theta = theta(:); 2g.lb&3W length_r = length(r); %I1@{>OxG if length_r~=length(theta) inP2y ?j error('zernfun:RTHlength', ... "<,lqIqA; 'The number of R- and THETA-values must be equal.') C{exvLQ end 8-Abg:) S{c/3k~ q<3nAE$?= % Check normalization: z.vQ1~s % -------------------- ["-rDyP if nargin==5 && ischar(nflag) 5`;SI36" isnorm = strcmpi(nflag,'norm'); a:FU- ^B4~ if ~isnorm q_M N error('zernfun:normalization','Unrecognized normalization flag.') coP->&(@U# end _v!7
|&\ else ZmA}i`
isnorm = false; ^q7V%{54 end /MZ<vnN7f >m%_`68 ah>c)1DA*H %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% u$ts>Q;5
% Compute the Zernike Polynomials &<&tdShI %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% m#"_x{oa MZgaQU g !np_B0` % Determine the required powers of r: `3TR`,= % ----------------------------------- !:{Qbv&T m_abs = abs(m); ak(s@@k rpowers = []; ) CGQ} for j = 1:length(n) 7 N}@zPAZ rpowers = [rpowers m_abs(j):2:n(j)]; G% F#I end xIdb9hm< rpowers = unique(rpowers); g2OnLEF]s {FJMcO= qe]D4K8`Q3 % Pre-compute the values of r raised to the required powers, E-A9lJWr % and compile them in a matrix: &RR;'wLoQT % ----------------------------- K\xz|Gq if rpowers(1)==0 w,%"+tY_ rpowern = arrayfun(@(p)r.^p,rpowers(2:end),'UniformOutput',false); Agcss20. rpowern = cat(2,rpowern{:}); "~r<ZG rpowern = [ones(length_r,1) rpowern]; `bP`.Wm else D*l(p5[ rpowern = arrayfun(@(p)r.^p,rpowers,'UniformOutput',false); oj 8r* rpowern = cat(2,rpowern{:}); dc$zW^i end Hav &vV B`SX3,3 ib,`0=0= O % Compute the values of the polynomials: ~WrpJjI[ % -------------------------------------- oodA&0{)d y = zeros(length_r,length(n)); rO87V!Cj for j = 1:length(n) D+T/ Z) s = 0:(n(j)-m_abs(j))/2; p$,7qGST pows = n(j):-2:m_abs(j); Bg|d2,im for k = length(s):-1:1 ys=2!P-[# p = (1-2*mod(s(k),2))* ... =!Ik5LiD prod(2:(n(j)-s(k)))/ ... ^B"LT>.[ prod(2:s(k))/ ... N"9^A^w8k prod(2:((n(j)-m_abs(j))/2-s(k)))/ ... ydWr&E5 prod(2:((n(j)+m_abs(j))/2-s(k))); 5BrN
uR$ idx = (pows(k)==rpowers); w1Bkz\95 y(:,j) = y(:,j) + p*rpowern(:,idx); |
BaEv\$K end h;=~%2Y [8u9q.IZ if isnorm LWr YKi y(:,j) = y(:,j)*sqrt((1+(m(j)~=0))*(n(j)+1)/pi); *r.%/^@ end JMAdsg/ end g?
vz\_ % END: Compute the Zernike Polynomials FQek+[ox %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% F=\
REq .7.G}z1 y[J9"k(@ % Compute the Zernike functions: p39$V[*g( % ------------------------------ NSVE3 idx_pos = m>0; %
J\G[dl idx_neg = m<0; G[}v?RLI ?0)K[Kd'Y GwO`@-}E z = y; >p&"X 2
@ if any(idx_pos) <gPM/4$G z(:,idx_pos) = y(:,idx_pos).*sin(theta*m(idx_pos)'); UV(`. end m9h<)D '> if any(idx_neg) L IKuK# z(:,idx_neg) = y(:,idx_neg).*cos(theta*m(idx_neg)'); ybpOk end CUDA<Fm 7a[6@ 0 Rb3|te % EOF zernfun Q7amp:JFb
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