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, E1rxuV|9 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, (L8z<id<z 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? h<f]hJ`ep 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? .:+&2#b IqmQQ_KH E\=23[0 ! ^U!T\qDi "+ 8Y{T function z = zernfun(n,m,r,theta,nflag) gK"E4{y_@ %ZERNFUN Zernike functions of order N and frequency M on the unit circle. 08 aZU % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N P<gr=& % and angular frequency M, evaluated at positions (R,THETA) on the ejPK-jxCa/ % unit circle. N is a vector of positive integers (including 0), and 9^1.nE(R& % M is a vector with the same number of elements as N. Each element oSqkAAGz\ % k of M must be a positive integer, with possible values M(k) = -N(k) r081.< % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, i_qR&X % and THETA is a vector of angles. R and THETA must have the same 095ZZ20 % length. The output Z is a matrix with one column for every (N,M) 6):^m{RH^ % pair, and one row for every (R,THETA) pair. #1` lJ % ZzV%+n7<Vx % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike Sg}]5Mn` % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), Rd{#cW~ % with delta(m,0) the Kronecker delta, is chosen so that the integral =^A/&[&31 % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, V9i[dF % and theta=0 to theta=2*pi) is unity. For the non-normalized Hb{G
RG70 % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. XDrNc!XN %
)\r;|DN % The Zernike functions are an orthogonal basis on the unit circle. v %fRq!~ % They are used in disciplines such as astronomy, optics, and Oe*+pReSD % optometry to describe functions on a circular domain. N=P+b%%:Z % C~aNOe
WR % The following table lists the first 15 Zernike functions. aI0}E O % ~kAen % n m Zernike function Normalization Z39I*-6F9W % -------------------------------------------------- \%D/]"@r % 0 0 1 1 $f^ \fa[ % 1 1 r * cos(theta) 2 }28,fb
/ % 1 -1 r * sin(theta) 2 vg/:q>o % 2 -2 r^2 * cos(2*theta) sqrt(6) ?~>#(Q % 2 0 (2*r^2 - 1) sqrt(3) QX j4cg % 2 2 r^2 * sin(2*theta) sqrt(6) 3d|n\!1r % 3 -3 r^3 * cos(3*theta) sqrt(8) - &/n[EE % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) e)2s2y@zi % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) cp7Rpqg % 3 3 r^3 * sin(3*theta) sqrt(8) 4 06.6jmv % 4 -4 r^4 * cos(4*theta) sqrt(10) 3bp'UEF^k % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) 3Vj,O?(Z % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) $'2yPoR % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) dkRG4
)~g % 4 4 r^4 * sin(4*theta) sqrt(10) ^"!j m % -------------------------------------------------- a:(.{z?nM % aN5 w % Example 1: 6mi:%)" % HFL(t] % % Display the Zernike function Z(n=5,m=1) kM,$0@ % x = -1:0.01:1; ZzuEw % [X,Y] = meshgrid(x,x); Ux Yb[Nbc % [theta,r] = cart2pol(X,Y); .l->O-= % idx = r<=1; Q'~2,%3< % z = nan(size(X)); 6(`Bl$M9 % z(idx) = zernfun(5,1,r(idx),theta(idx)); )`ZTu -| % figure G3&l|@5 % pcolor(x,x,z), shading interp Z+< zKn} % axis square, colorbar P7Ws$7x % title('Zernike function Z_5^1(r,\theta)') J \@yP % buRK\C % Example 2: {T]^C % 6^]Y]) % % Display the first 10 Zernike functions 9Xg+$/ % x = -1:0.01:1; C>vp
oCA % [X,Y] = meshgrid(x,x); V+mTo^ % [theta,r] = cart2pol(X,Y); >~kSe=Hsb4 % idx = r<=1; 4$=Dq$4z % z = nan(size(X)); xsq+RBJi % n = [0 1 1 2 2 2 3 3 3 3]; os]P6TFFX? % m = [0 -1 1 -2 0 2 -3 -1 1 3]; 0!c^pOq6 % Nplot = [4 10 12 16 18 20 22 24 26 28]; 6Y|jK<n?H % y = zernfun(n,m,r(idx),theta(idx)); .I@jt?6X % figure('Units','normalized') g$\Z-!( % for k = 1:10 75t\= 6# % z(idx) = y(:,k); mE"?{~XVL % subplot(4,7,Nplot(k)) l0m\2Ttf % pcolor(x,x,z), shading interp Z2]ySyt] % set(gca,'XTick',[],'YTick',[]) +K3SAGm % axis square 7B`,q-x. % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) 6}YWM]c% % end do2~LmeW % S0_#h) % See also ZERNPOL, ZERNFUN2. jrMY]Ea2` 5y. n A d0dg2Gw % Paul Fricker 11/13/2006 ,1"w2, = &J)q _Z8 9Se7
1
vxxa,KR/y R0R Xw % Check and prepare the inputs: !vU$^>zo~ % ----------------------------- ?d*0-mhQ, if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) xhAORhw# error('zernfun:NMvectors','N and M must be vectors.') eGZX6Q7m end +X4O.6Mn v(vLk\K7 gHLBtl/ if length(n)~=length(m) }U=|{@% error('zernfun:NMlength','N and M must be the same length.') JfmNI~% end GbC-6.~ X]J]7\4tF\ xS) njuq4 n = n(:); -S]yXZ m = m(:); (~~*PT- if any(mod(n-m,2)) =_%i5]89P error('zernfun:NMmultiplesof2', ... "p43# 'All N and M must differ by multiples of 2 (including 0).') l[EnFbD6 end <MhjvHg /P~@__XN #"^F:: b- if any(m>n) <_HK@E<_HO error('zernfun:MlessthanN', ... \bze-|C 'Each M must be less than or equal to its corresponding N.') CKShz]1 end yub| 1]HEwTT/1_ 2\flTO2Ny if any( r>1 | r<0 )
>:whNp error('zernfun:Rlessthan1','All R must be between 0 and 1.') m_Owe/BC#m end ), >jBYMJ J`U\3:b`SP D ];%Ey if ( ~any(size(r)==1) ) || ( ~any(size(theta)==1) ) ?)$+W+vK error('zernfun:RTHvector','R and THETA must be vectors.') tZS-e6*S end ;P9P2&c8c gC81ICM SF.4["$ r = r(:); 2IgTB|2 theta = theta(:); 0n25{N length_r = length(r); d\Xi1&& if length_r~=length(theta) fk%yi[ error('zernfun:RTHlength', ... N;cEf7+f 'The number of R- and THETA-values must be equal.') ].f28bY end ~7$E\w6 ;[*jLi,uc }cK<2J# % Check normalization: l0Myem
v?z % --------------------
y{hy if nargin==5 && ischar(nflag) 49%qBO$R isnorm = strcmpi(nflag,'norm'); Nf0'>`/ if ~isnorm _qg)^M 6 error('zernfun:normalization','Unrecognized normalization flag.') 0MK|spc end !r:X`~\a else x!klnpGp isnorm = false; gxEa?QH end tGGv 2TCEy ^h+,Kn0@ 8(R%?>8 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% w
^ v*1KA& % Compute the Zernike Polynomials OhmKjY/} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% W2L: R:zPU s hbPy % Determine the required powers of r: ,?Pn-aC+ % ----------------------------------- oQgd]|v m_abs = abs(m); 6Z~u2& rpowers = []; v)|[= for j = 1:length(n) D}|PBR rpowers = [rpowers m_abs(j):2:n(j)]; iB[>uW end LG6VeYe|\X rpowers = unique(rpowers); (are2!Oq -%]O-' <rUH\z5cP % Pre-compute the values of r raised to the required powers, ZV}"k_+- % and compile them in a matrix: 1:<= zqh0 % ----------------------------- 9-;ujl?{ if rpowers(1)==0 fY@Y$S`Fh rpowern = arrayfun(@(p)r.^p,rpowers(2:end),'UniformOutput',false); ;SAurG$ rpowern = cat(2,rpowern{:}); 5~T`R~Uqb rpowern = [ones(length_r,1) rpowern]; }Z
T{ else `IQ01FuP rpowern = arrayfun(@(p)r.^p,rpowers,'UniformOutput',false); 6e,|HV rpowern = cat(2,rpowern{:}); Ad)Po end ^R* _Q,o# aY 8"Sw|4 0z)
8i P % Compute the values of the polynomials:
,lX5-1H % -------------------------------------- ugexkdgM y = zeros(length_r,length(n)); ji(W+tQ2Y' for j = 1:length(n) QjH;'OVt s = 0:(n(j)-m_abs(j))/2; :TU;%@7 pows = n(j):-2:m_abs(j); ,]?Xf> for k = length(s):-1:1 ,L#Qy>MOb p = (1-2*mod(s(k),2))* ... sBP.P7u prod(2:(n(j)-s(k)))/ ... \u@4eBAV prod(2:s(k))/ ... CW*Kdt prod(2:((n(j)-m_abs(j))/2-s(k)))/ ... hS]g^S==2h prod(2:((n(j)+m_abs(j))/2-s(k))); 2XhtK idx = (pows(k)==rpowers); ,4oYKJ$+h y(:,j) = y(:,j) + p*rpowern(:,idx); 3R(GO.n=] end :.kc1_veYS fl| 8#\r if isnorm oh+Q}Fa: y(:,j) = y(:,j)*sqrt((1+(m(j)~=0))*(n(j)+1)/pi); $o
rN>M42 end RAMkTS end nR)/k,3W % END: Compute the Zernike Polynomials L><# I %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 6^U8Utx P3|_RHIb ?sQOz[ig; % Compute the Zernike functions: Y<('G5A % ------------------------------ 3nb&Z_/e idx_pos = m>0; n_;qB7,, idx_neg = m<0; W7I.S5 ]v=*WK >ZMB}pt` z = y; +`pS 7d if any(idx_pos) E(DNK z(:,idx_pos) = y(:,idx_pos).*sin(theta*m(idx_pos)'); om%L>zfB end ~(E.$y7P if any(idx_neg) tfzIem z(:,idx_neg) = y(:,idx_neg).*cos(theta*m(idx_neg)'); :^7P. lhK end ""cnZZ5) eELJDSd
BV )eFXjnHN % EOF zernfun <CrNDY
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