| 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, @uA=v/>+ 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, ! |4fww 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? )S?. YCv? 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? SB~HHx09 ~5`p/.L)ZD UU\wP(f [0c7fH`8V 5rp,xk! function z = zernfun(n,m,r,theta,nflag) -c%#Hd %ZERNFUN Zernike functions of order N and frequency M on the unit circle. cdd6*+E % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N HGycF|]2 % and angular frequency M, evaluated at positions (R,THETA) on the mq#8[D % unit circle. N is a vector of positive integers (including 0), and RJ}%pA4I % M is a vector with the same number of elements as N. Each element xXb7/.*qE % k of M must be a positive integer, with possible values M(k) = -N(k) a|}v?z\ % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, 7`xeuK % and THETA is a vector of angles. R and THETA must have the same WAq)1gwN % length. The output Z is a matrix with one column for every (N,M) hk*@<ff % pair, and one row for every (R,THETA) pair. ohEIr2 % 7Eb |AR % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike %u=b_4K"j % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), QC\r|RXW % with delta(m,0) the Kronecker delta, is chosen so that the integral m8}c(GwcP % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, I{nrOb1G( % and theta=0 to theta=2*pi) is unity. For the non-normalized .)(5F45Wg % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. \d-H+t] % !LI
8Xk % The Zernike functions are an orthogonal basis on the unit circle. @kstG3@ % They are used in disciplines such as astronomy, optics, and `@<>"ff#F % optometry to describe functions on a circular domain. wWYo\WH' % t[e`wj+qz % The following table lists the first 15 Zernike functions. m!Y4+KTwD` % idzc4jR6BT % n m Zernike function Normalization x*'2%3C~ % -------------------------------------------------- E;1QD/E$ % 0 0 1 1 WRCf[5 % 1 1 r * cos(theta) 2 =Ju%3ptH0 % 1 -1 r * sin(theta) 2 :,Zs{\oI3 % 2 -2 r^2 * cos(2*theta) sqrt(6) Jb;@'o6 % 2 0 (2*r^2 - 1) sqrt(3) Z\[6'R4.# % 2 2 r^2 * sin(2*theta) sqrt(6) "J(T?|t % 3 -3 r^3 * cos(3*theta) sqrt(8) O'rz % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) x@*RF:\} % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) ,7:?Du} % 3 3 r^3 * sin(3*theta) sqrt(8) jjT)3
c:J[ % 4 -4 r^4 * cos(4*theta) sqrt(10)
Cl>|*h+m % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) 'Lu d=u{ % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) m!-R}PQC % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) E"<-To % 4 4 r^4 * sin(4*theta) sqrt(10) Mg~62u % -------------------------------------------------- |S6L[Uo % zhZ!!b^6< % Example 1: Mni@@W % >PS`;S!( % % Display the Zernike function Z(n=5,m=1) 2F&VG|" % x = -1:0.01:1; Xk>YiV",? % [X,Y] = meshgrid(x,x); )+ (GE % [theta,r] = cart2pol(X,Y); ]q`'l_O % idx = r<=1; MA,7|s
% z = nan(size(X)); ^ *1hz< % z(idx) = zernfun(5,1,r(idx),theta(idx)); 'O^<i`8U] % figure S*l=FRFI % pcolor(x,x,z), shading interp #O1%k;BL % axis square, colorbar dy.U; % title('Zernike function Z_5^1(r,\theta)') _aP2gH % 45 B
|U % Example 2: 'H8b+ % GR,gCtG+L % % Display the first 10 Zernike functions ' e:rL. % x = -1:0.01:1; e3.q8r % [X,Y] = meshgrid(x,x); &{e:6t % [theta,r] = cart2pol(X,Y); .b|!FWHNS % idx = r<=1; .+A2\F.^ % z = nan(size(X));
YZy%]i=1 % n = [0 1 1 2 2 2 3 3 3 3]; LjySO2 % m = [0 -1 1 -2 0 2 -3 -1 1 3]; ' OXL'_Xl % Nplot = [4 10 12 16 18 20 22 24 26 28]; v*JXrB&x % y = zernfun(n,m,r(idx),theta(idx)); yvCX
is % figure('Units','normalized') ?_`X8Ok % for k = 1:10 e~ %=H 0n % z(idx) = y(:,k); K3^2;j1F Q % subplot(4,7,Nplot(k))
#_kV o3 % pcolor(x,x,z), shading interp Yn5a4 % set(gca,'XTick',[],'YTick',[]) Ex+E66bE % axis square /5Tp)h| % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) Oj1B @QE % end a}g<<{ % [_-[S % See also ZERNPOL, ZERNFUN2. $O^"OQ_@ 9P& \2/ { ('6sW/F*ab % Paul Fricker 11/13/2006 MZvxcr{x PUEEfq!% F;8Uvj ]sDlZJX<M f{j`d&| % Check and prepare the inputs: gaU(ebsE % ----------------------------- ,uL}O]L if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) bScW<DZJ- error('zernfun:NMvectors','N and M must be vectors.') a8 .x=j< end *?~&O.R" LMaY}m> mvu$ if length(n)~=length(m) &?*H`5#?G error('zernfun:NMlength','N and M must be the same length.') i4\DSQJ end ~j yl Qe;R3D=T; 5Ve
T8/7Q n = n(:); d`3>@*NR< m = m(:); YhO-ecN if any(mod(n-m,2)) |$D`* error('zernfun:NMmultiplesof2', ... \t
^9UN 'All N and M must differ by multiples of 2 (including 0).') e=Q{CsP end !h70 <Q^ |3C5"R3ZGO P"a9+ti+' if any(m>n) 5@^['S4%8* error('zernfun:MlessthanN', ... fzr0dcNgM 'Each M must be less than or equal to its corresponding N.') P;K <P end lbm ,# J0UF( -"5r-q q* if any( r>1 | r<0 ) LLPbZ9q error('zernfun:Rlessthan1','All R must be between 0 and 1.') /-Y.A<ieN8 end CD pLV: pwmH(94$0 Gg3<
}( if ( ~any(size(r)==1) ) || ( ~any(size(theta)==1) ) wZb77 error('zernfun:RTHvector','R and THETA must be vectors.') "$ U!1 end kqZ+e/o>O9 s!?T$@a= :xZ^Jq91 r = r(:); u&r+ylbsI theta = theta(:); cm`x;[e6l length_r = length(r); 7 ;SI= if length_r~=length(theta) 'Omj-o'tn9 error('zernfun:RTHlength', ... W$`p ,$ .n 'The number of R- and THETA-values must be equal.') -op(26:W< end lx&;?QQ [Mp8" b$N&sZ % Check normalization: sW0<f&3 % -------------------- ]::g-&%Um if nargin==5 && ischar(nflag) h`pXUnEZ isnorm = strcmpi(nflag,'norm'); b2XUZ5 if ~isnorm p]x9hZ error('zernfun:normalization','Unrecognized normalization flag.') ,XYtoZa end gJ?Vk<hp else wg=-&- isnorm = false; +t*Ks_V,* end CYZ0F5+t ,_I#+XiXY E\vW>g*W %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% ~c${?uf % Compute the Zernike Polynomials BL H~`N3U %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% ehyCAp0oI a$]i8AeG L]{1@~E:q % Determine the required powers of r: &'oZ]}^0 % ----------------------------------- ~
}?*v} m_abs = abs(m); &nfGRb rpowers = []; O^sOv!!RH/ for j = 1:length(n) ObSRd$M rpowers = [rpowers m_abs(j):2:n(j)]; 3oMhsQz~z end ;}4^WzmK^( rpowers = unique(rpowers); o>o! -uf 3pjK`"Nmz\ y28 e=i % Pre-compute the values of r raised to the required powers, P:fcbfH+ % and compile them in a matrix: yR[htD` % ----------------------------- N_R(i3c6U! if rpowers(1)==0 G$-[(eu- rpowern = arrayfun(@(p)r.^p,rpowers(2:end),'UniformOutput',false); ^e(*{K;8 rpowern = cat(2,rpowern{:}); <L+y
6B rpowern = [ones(length_r,1) rpowern]; /eY}0q% else i?B(I4a!G rpowern = arrayfun(@(p)r.^p,rpowers,'UniformOutput',false); S94S[j0D rpowern = cat(2,rpowern{:}); 1XJLGMW, end eKW^\ I6rB_~]h wOF";0EN % Compute the values of the polynomials: )=%TIkeF % -------------------------------------- _7b' i6- y = zeros(length_r,length(n)); i2X%xYv ^ for j = 1:length(n) `}S;_g! s = 0:(n(j)-m_abs(j))/2; Lb} $)AcC pows = n(j):-2:m_abs(j); oP_}C[ for k = length(s):-1:1 XxLauJP
K p = (1-2*mod(s(k),2))* ... NM4b]> prod(2:(n(j)-s(k)))/ ... ayrCLv prod(2:s(k))/ ... `XrF , prod(2:((n(j)-m_abs(j))/2-s(k)))/ ... ?XB[awTD~ prod(2:((n(j)+m_abs(j))/2-s(k))); ]La~Bh6;m idx = (pows(k)==rpowers); JXq l=/% y(:,j) = y(:,j) + p*rpowern(:,idx); 6D/K=- end M6XpauR- c|<E~_.w@ if isnorm v`Yj) y(:,j) = y(:,j)*sqrt((1+(m(j)~=0))*(n(j)+1)/pi); % 9} ?*U end _p;=]#+c& end D] +]Br8 % END: Compute the Zernike Polynomials FgnPh%[u %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% xP-\)d-.aN Eal*){"<,? si#1sdR % Compute the Zernike functions: bE6bx6=u % ------------------------------ L)X[$: idx_pos = m>0; ZK5
wZU idx_neg = m<0; ?g9oiOhnG Dy|)u1? /&+*X)#v z = y; x &*2R#Ai if any(idx_pos) 8 DPn5E#M1 z(:,idx_pos) = y(:,idx_pos).*sin(theta*m(idx_pos)'); C9^C4
end i)=
\-C if any(idx_neg) v\dP z(:,idx_neg) = y(:,idx_neg).*cos(theta*m(idx_neg)'); W9:(P end ;VS$xnZ 2x!cblo Zmz $
hr % EOF zernfun f"R'Q|7D
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