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, 5+\[x` 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, `CA-s 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? |b7v(Hx 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? NNLZ38BV7 ) (unL`y ;wwhW|A _TfG-Ae !#j
y=A function z = zernfun(n,m,r,theta,nflag) };6[Byf %ZERNFUN Zernike functions of order N and frequency M on the unit circle. [* ,k % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N Wjc1 EW!2x % and angular frequency M, evaluated at positions (R,THETA) on the ~Mbo`:>(4v % unit circle. N is a vector of positive integers (including 0), and ,~u 5SR % M is a vector with the same number of elements as N. Each element n[8ju,= % k of M must be a positive integer, with possible values M(k) = -N(k) zs|R#?a= % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, M}=X/*T % and THETA is a vector of angles. R and THETA must have the same LsH&`G^< % length. The output Z is a matrix with one column for every (N,M) A:PQIcR;V % pair, and one row for every (R,THETA) pair. (jd)sf6Tj[ % !2R~/Rg % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike d
4w+5H"u % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), KI)jP(( % with delta(m,0) the Kronecker delta, is chosen so that the integral (8qD'(@ % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, H&\[iZ|-N % and theta=0 to theta=2*pi) is unity. For the non-normalized 2k;>nlVxX % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. Q%)da)0:c % c<- F_+[ % The Zernike functions are an orthogonal basis on the unit circle. q}P< Ejq} % They are used in disciplines such as astronomy, optics, and lx_jy>$}r % optometry to describe functions on a circular domain. kx&Xk0F_g % )d5Hv2/0 % The following table lists the first 15 Zernike functions. T n.Cj5 % !iUFD*~r~ % n m Zernike function Normalization {R<0'JU % -------------------------------------------------- 2L"$p? % 0 0 1 1 &XAG|
# % 1 1 r * cos(theta) 2 ;D.a |(Q % 1 -1 r * sin(theta) 2 WO$9Svh8 % 2 -2 r^2 * cos(2*theta) sqrt(6) Ey<vvZ % 2 0 (2*r^2 - 1) sqrt(3) ?.Mw % 2 2 r^2 * sin(2*theta) sqrt(6) qd$Y"~Mco % 3 -3 r^3 * cos(3*theta) sqrt(8) Xi"+{6
% 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) JLgk? % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) Wy1#K)LRb % 3 3 r^3 * sin(3*theta) sqrt(8) "Kky|(EQ$$ % 4 -4 r^4 * cos(4*theta) sqrt(10) A+Uil\% % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) !bs{/? % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) RW| LL@r % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) s
zBlyT % 4 4 r^4 * sin(4*theta) sqrt(10) 6r % -------------------------------------------------- U9^o"vT % ~*"]XE?M % Example 1: 6{Y3-Pxg % <ua` WRQr % % Display the Zernike function Z(n=5,m=1) {l/j?1Dxq % x = -1:0.01:1; rXl ~D! % [X,Y] = meshgrid(x,x); ueI1O/Mi % [theta,r] = cart2pol(X,Y); MI8f(ZJK5 % idx = r<=1; +9mE1$C % z = nan(size(X)); I
ACpUB % z(idx) = zernfun(5,1,r(idx),theta(idx)); t6-He~ % figure ]`@= ;w % pcolor(x,x,z), shading interp t!}QG"ma % axis square, colorbar :
L}Fm2^ % title('Zernike function Z_5^1(r,\theta)') bm/pLC6%. % <X>lA % Example 2: ~)J]`el,Q % D*7JE % % Display the first 10 Zernike functions Y]>!uwn % x = -1:0.01:1; (41BUX % [X,Y] = meshgrid(x,x); Gg'sgn
% [theta,r] = cart2pol(X,Y); 3JhT % idx = r<=1; vbFi#|EU % z = nan(size(X)); o8<0#W@S % n = [0 1 1 2 2 2 3 3 3 3]; %Xe#'qNq) % m = [0 -1 1 -2 0 2 -3 -1 1 3]; War<a#0 % Nplot = [4 10 12 16 18 20 22 24 26 28]; kH;DAphk % y = zernfun(n,m,r(idx),theta(idx)); 6( #fGH&[ % figure('Units','normalized') Q=B>Q % for k = 1:10 k OYF]^uJ % z(idx) = y(:,k); 8w,+Y]X<P[ % subplot(4,7,Nplot(k)) "&$ [@c % pcolor(x,x,z), shading interp <jt_<p
+ % set(gca,'XTick',[],'YTick',[]) 9E`WZo^. % axis square hM_0/o- % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) QuB`}rfLf % end 5(9SIj^O % kSL7WQe?j % See also ZERNPOL, ZERNFUN2. kHWW\?O FYOQ}N
4o/}KUu(* % Paul Fricker 11/13/2006
IBP3 JAt$WW{ :? uUh hk5[ N= c>SFttbU % Check and prepare the inputs: 4lM)ZDg % ----------------------------- X667*L^ if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) J#1-Le8@ error('zernfun:NMvectors','N and M must be vectors.') ot%^FvQ[c end "+0Yhr ? ON,sN MWGs:tpL4 if length(n)~=length(m) ;+-@AYl error('zernfun:NMlength','N and M must be the same length.') u"$=:GK end _cRCG1CJ 9N+3S2sBx& 7lLh4__;`6 n = n(:); z_i(o m = m(:); RZY[DoF8u if any(mod(n-m,2)) O c,E\~ error('zernfun:NMmultiplesof2', ... g3 6:OK" 'All N and M must differ by multiples of 2 (including 0).') Ru&>8Ln0 end Ux/|D_rlf s'7PHP)LOJ |]M|IX8
o if any(m>n) "_f~8f`y error('zernfun:MlessthanN', ... k^H&IS! 'Each M must be less than or equal to its corresponding N.') B|f
=hlY end 3-=f@uH! Za110oF C{*' p+f if any( r>1 | r<0 ) /VmtQ{KTt+ error('zernfun:Rlessthan1','All R must be between 0 and 1.') @sr~&YhA end "^froQ{"T \ 4`:~c xS'Kr.S
if ( ~any(size(r)==1) ) || ( ~any(size(theta)==1) ) 5V $H?MW> error('zernfun:RTHvector','R and THETA must be vectors.') = :/4) end !=3Ce3- Nc da~h
Q bo-AM] r = r(:); /g`!Zn8a theta = theta(:); '+s ?\X4VC length_r = length(r); W?:e4:Q if length_r~=length(theta) [yhK4A error('zernfun:RTHlength', ... K\trT!I 'The number of R- and THETA-values must be equal.') V+$^4Ht end {V^|9j:\K /ucS*m:<x Oxp!G7qfo % Check normalization: 5r` x\ % -------------------- '% if< / if nargin==5 && ischar(nflag) '8"nXuL- isnorm = strcmpi(nflag,'norm'); L%`MoTpKq if ~isnorm jhJ'fI error('zernfun:normalization','Unrecognized normalization flag.') RxYC]R^78 end W%wc@.P else 9_b_O T isnorm = false; W; zzc1v end 1\X_B`xwD %HD0N& Y-s6Z\ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% /8? u2
q % Compute the Zernike Polynomials 6QYHPz %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% (
}RJW: ]~@uStHn u_=^Bd % Determine the required powers of r: VvUP;o&/ % ----------------------------------- 0t?g! m_abs = abs(m); 0aqq*e'c rpowers = []; o}=c(u for j = 1:length(n) [y&uc rpowers = [rpowers m_abs(j):2:n(j)]; IcA]B?+ end 3De(:c)@ rpowers = unique(rpowers); $Xr4=9(|7 +7mUX }F';"ybrU) % Pre-compute the values of r raised to the required powers, W) ?s''WE; % and compile them in a matrix: bcYGkvGbO % ----------------------------- ^Z+p_;J$p if rpowers(1)==0
<64#J9T^ rpowern = arrayfun(@(p)r.^p,rpowers(2:end),'UniformOutput',false); o&)v{q rpowern = cat(2,rpowern{:}); 7P:/ (P rpowern = [ones(length_r,1) rpowern]; Se.qft?D%( else T`2a) rpowern = arrayfun(@(p)r.^p,rpowers,'UniformOutput',false); *pYawT rpowern = cat(2,rpowern{:}); d-jZ 5nl( end =>-W!Of N *,[(q jG%J.u^k % Compute the values of the polynomials: tkP& =$ % -------------------------------------- (7C$'T-ZK y = zeros(length_r,length(n)); |)OC1=As for j = 1:length(n) cp&1yB
s = 0:(n(j)-m_abs(j))/2; |F +n7 pows = n(j):-2:m_abs(j); s{:Thgv,9 for k = length(s):-1:1 -U{!'e8YiN p = (1-2*mod(s(k),2))* ... >?jmeD3u prod(2:(n(j)-s(k)))/ ... F8xu&Vk0: prod(2:s(k))/ ... a5/r|BiBK prod(2:((n(j)-m_abs(j))/2-s(k)))/ ... cv_t2m prod(2:((n(j)+m_abs(j))/2-s(k))); 2S//5@~_m idx = (pows(k)==rpowers); YbF}>1/" y(:,j) = y(:,j) + p*rpowern(:,idx); >@EwfM4[e end 63'L58O 3uL$+F if isnorm y]g5S-G y(:,j) = y(:,j)*sqrt((1+(m(j)~=0))*(n(j)+1)/pi); %edTW[C` end k)zBw(wr end AZ
SaI % END: Compute the Zernike Polynomials b_)SMAsO7 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 8l<~zIoO E( *S]Z[ p.5 *`, ) % Compute the Zernike functions: 65GC7 >[ % ------------------------------ PHMp,z8 idx_pos = m>0; _TyQC1 d idx_neg = m<0; m4^VlE,`Dh CoV@{Pi 1[-RIN;U8 z = y; |!J_3*6$>* if any(idx_pos) CVZ4:p z(:,idx_pos) = y(:,idx_pos).*sin(theta*m(idx_pos)'); r;O?`~2'4 end [6?x 6_M if any(idx_neg) F.D6O[pZ z(:,idx_neg) = y(:,idx_neg).*cos(theta*m(idx_neg)'); knzQ)iv&& end u4xJ-Vu Ls*Vz,3!5 tPDB'S:&3 % EOF zernfun 'cY@Dqg1
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