| 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, S_!R^^ySG9 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, >1XL;)IL> 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? ;2W2MZ!TF 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? Hz4uZ*7\| $T)d!$ ]]V^:"ne #6FaIq92V 0P:F97"1, function z = zernfun(n,m,r,theta,nflag) p[P[#IeL %ZERNFUN Zernike functions of order N and frequency M on the unit circle. aT/KT,! % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N HU3Vv<lz % and angular frequency M, evaluated at positions (R,THETA) on the |7S:l9; % unit circle. N is a vector of positive integers (including 0), and c20|Cx2m % M is a vector with the same number of elements as N. Each element qi[(*bFK7 % k of M must be a positive integer, with possible values M(k) = -N(k) ]EX--d<_` % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, LI$L9eNv;Y % and THETA is a vector of angles. R and THETA must have the same 2vXGO|W % length. The output Z is a matrix with one column for every (N,M) i0&)
N,5_ % pair, and one row for every (R,THETA) pair. Y=WR6!{ % 0XQ-
% Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike w\v&3T % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), tYI]=: % with delta(m,0) the Kronecker delta, is chosen so that the integral { ;' :h % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, 1(F'~i|5 % and theta=0 to theta=2*pi) is unity. For the non-normalized 0eaUorm) % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. Oylp:_<aT % pgfu+K7?w % The Zernike functions are an orthogonal basis on the unit circle. <VgE39 [ % They are used in disciplines such as astronomy, optics, and $@4e(Zrmo % optometry to describe functions on a circular domain. `w(sXkeaI % :6sGX p % The following table lists the first 15 Zernike functions. _PdAN= C3 % gNi}EP5> % n m Zernike function Normalization 0wYiu % -------------------------------------------------- 1o)=GV1 % 0 0 1 1 F_~6n]Sr % 1 1 r * cos(theta) 2 oYGUjI % 1 -1 r * sin(theta) 2 8ST~$!z$ % 2 -2 r^2 * cos(2*theta) sqrt(6) 8s&2gn1 % 2 0 (2*r^2 - 1) sqrt(3) 7vdHR\#;$ % 2 2 r^2 * sin(2*theta) sqrt(6) n+S&!PB % 3 -3 r^3 * cos(3*theta) sqrt(8) EXH!glR[$ % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) j!"iYtgV % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) >fhSaeN % 3 3 r^3 * sin(3*theta) sqrt(8) w-8)YJ Y % 4 -4 r^4 * cos(4*theta) sqrt(10) KXDz'9_ % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) pIrv$^ % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) 7a27^b % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) N)Qlkz$X % 4 4 r^4 * sin(4*theta) sqrt(10) L)=8mF. % -------------------------------------------------- !cv6 #: % MgSp.<! % Example 1: /G[+E&vj % N_*u5mfQX % % Display the Zernike function Z(n=5,m=1) vJzx Py| % x = -1:0.01:1; ^S:cNRSW" % [X,Y] = meshgrid(x,x); R\i]O % [theta,r] = cart2pol(X,Y); HK=CP0H % idx = r<=1; /:Rn"0 % z = nan(size(X)); c@)p Ki#W % z(idx) = zernfun(5,1,r(idx),theta(idx)); =k_XKxd % figure G<Th<JF)Q % pcolor(x,x,z), shading interp _g^E%@'W % axis square, colorbar 6qY\7R2+ % title('Zernike function Z_5^1(r,\theta)') `mQP{od?"? % `8qT['`#R % Example 2: s n=zh1 A % #.RG1-L % % Display the first 10 Zernike functions @5JLjCN % x = -1:0.01:1; $&c<T4 $d % [X,Y] = meshgrid(x,x); $a)JCErN % [theta,r] = cart2pol(X,Y); Qj{$dqmDN % idx = r<=1; h,Y{t?Of % z = nan(size(X)); `,hW;p>- % n = [0 1 1 2 2 2 3 3 3 3]; 7Q<Kha % m = [0 -1 1 -2 0 2 -3 -1 1 3]; #%9oQ6nO % Nplot = [4 10 12 16 18 20 22 24 26 28]; :4Id7Ce % y = zernfun(n,m,r(idx),theta(idx)); )<m=YI
;< % figure('Units','normalized') ^/ULh,w!fP % for k = 1:10 YY1{v?[ % z(idx) = y(:,k); zWP.1 aA& % subplot(4,7,Nplot(k)) f/$-Nl. % pcolor(x,x,z), shading interp ;Hz`0V % set(gca,'XTick',[],'YTick',[]) L5i#Kh_ % axis square qBf wN 1 % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) 1 P(&GYc % end KY;uO 8Te % Po2_ 0uX % See also ZERNPOL, ZERNFUN2. HMl!?%% wliGds oP 6.t-<dU % Paul Fricker 11/13/2006 U4
go8 ^!-E`<jW8 VPq5xSc? Rh05W_?Js %Q>~7P % Check and prepare the inputs: "^e}C@ % ----------------------------- {7j6$.7J$& if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) \.XT:B_ error('zernfun:NMvectors','N and M must be vectors.') o`JlXuG?o end (mOqv9pn rH
[+/&w5 +aXMH T"U if length(n)~=length(m)
$\JQGic` error('zernfun:NMlength','N and M must be the same length.') DKaG?Y,*p end )- Wn'C'Z dvrvpDoE. Lv`8jSt\ n = n(:); 5 O{Ip- m = m(:); 5Tcl<Y6l if any(mod(n-m,2)) f0N)N}y error('zernfun:NMmultiplesof2', ... Dn{19V.L 'All N and M must differ by multiples of 2 (including 0).') f6dE\ end
0&SrKn tXb7~aO Rd;~'gbG if any(m>n) ;c \zgs~"T error('zernfun:MlessthanN', ... Occ8Hk/l. 'Each M must be less than or equal to its corresponding N.') 7#~m:K@ end KNUMz4 af`f*{Co3 b>>=d)R if any( r>1 | r<0 ) NXV~[ error('zernfun:Rlessthan1','All R must be between 0 and 1.') sEgeS9a{ end "\R@lUx.Y T[8"u<O96 1Q2k>q8 if ( ~any(size(r)==1) ) || ( ~any(size(theta)==1) ) Jte:l:yjtA error('zernfun:RTHvector','R and THETA must be vectors.') [/#k$- end ki][qvXJ nw]e_sm !m/Dd0 r = r(:); k:HSB</} theta = theta(:); }GU6Q|s[u[ length_r = length(r); s].'@_~s if length_r~=length(theta) c+G :@% error('zernfun:RTHlength', ... c?3F9w# 'The number of R- and THETA-values must be equal.') \I o?ul}za end 41+E U Mc D+vl%(g vY+_tpuEH % Check normalization: +oKpA\mz % -------------------- .AmM%I4K if nargin==5 && ischar(nflag) U}C#:Xi>$ isnorm = strcmpi(nflag,'norm'); `'WY'\|C if ~isnorm l7r N
error('zernfun:normalization','Unrecognized normalization flag.') g`f6gxc end 'zD;:wT else J1v0
\ isnorm = false; ~%!U,)- end =LeVJGF 9rvxp; ,h)T( %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% _-yF9g"I % Compute the Zernike Polynomials D*2p %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% LZAj4|~,m 1wNY}3 !kk %;XSZ % Determine the required powers of r: V2sB[Mw % ----------------------------------- Le$u$ulS m_abs = abs(m); & b^*N5<Z rpowers = []; '>lPq tdZ for j = 1:length(n) R.WsC bU rpowers = [rpowers m_abs(j):2:n(j)]; @W5hrei end +\(ay"+ d rpowers = unique(rpowers); }W>[OY0^A lO[jf6gB ,I:m*.q % Pre-compute the values of r raised to the required powers, @Y<ZT;J % and compile them in a matrix: CFrHNU % ----------------------------- Vh[o[ U if rpowers(1)==0 Rb>RjHo S rpowern = arrayfun(@(p)r.^p,rpowers(2:end),'UniformOutput',false); uJ5%JB("E rpowern = cat(2,rpowern{:}); r+.4|u rpowern = [ones(length_r,1) rpowern]; ]TZWFL- else +AC-f2 rpowern = arrayfun(@(p)r.^p,rpowers,'UniformOutput',false); p'c<v)ia rpowern = cat(2,rpowern{:}); D"XQ!1B% end XTXo xZ#w 2P>za\ z&J ow/ % Compute the values of the polynomials: Mh/>qyS*2 % -------------------------------------- ^3@a0J=F y = zeros(length_r,length(n)); $j2)_(<A%Q for j = 1:length(n) 6!D s = 0:(n(j)-m_abs(j))/2; /Rcd}rO pows = n(j):-2:m_abs(j); 3V!&y/c< for k = length(s):-1:1 I)/7M}t` p = (1-2*mod(s(k),2))* ... %oKc?'L0 prod(2:(n(j)-s(k)))/ ... V+<AG*[ prod(2:s(k))/ ... *SG2k .$ prod(2:((n(j)-m_abs(j))/2-s(k)))/ ... b2-|e_x prod(2:((n(j)+m_abs(j))/2-s(k))); L<>NL$CrN idx = (pows(k)==rpowers); zc~xWy+ y(:,j) = y(:,j) + p*rpowern(:,idx); 8q[WfD end nZ+5@(
* yl+)I if isnorm iwx0V y(:,j) = y(:,j)*sqrt((1+(m(j)~=0))*(n(j)+1)/pi); Dj&bHC5% end [?6D1b[ end Z/UVKJm>: % END: Compute the Zernike Polynomials MxA'T(Ay %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 6e-h;ylS GYmB xX87 9nAK6$/ % Compute the Zernike functions: T@.m^|~ % ------------------------------ V~"d`j idx_pos = m>0; R6o<p<fTh idx_neg = m<0; )KQv4\0y< L*oLKigT 3Ty{8oUs^ z = y; tpzdYokh> if any(idx_pos) ;4#8#; z(:,idx_pos) = y(:,idx_pos).*sin(theta*m(idx_pos)'); fv'P!+)t end XFAt\g if any(idx_neg) h#;K9#x6 z(:,idx_neg) = y(:,idx_neg).*cos(theta*m(idx_neg)'); }ucg!i3C end Jm,X~Si 84\o7@$# 6]49kHgMhe % EOF zernfun CP#MNNvgrw
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