| 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, n5tsaU; 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, ^E+fmY2a 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? Q`-Xx 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? h1f 05 i]qxF&1 ]4K4Nh~ sx' eu;S 3hA5"G+7 function z = zernfun(n,m,r,theta,nflag) 3 `NSSS %ZERNFUN Zernike functions of order N and frequency M on the unit circle. Ya!PV&"Z % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N Re*~C: % and angular frequency M, evaluated at positions (R,THETA) on the ]bstkf}~u % unit circle. N is a vector of positive integers (including 0), and K\mFb % M is a vector with the same number of elements as N. Each element LIyb+rH#yg % k of M must be a positive integer, with possible values M(k) = -N(k) $IdU % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, =gZA9@]W2 % and THETA is a vector of angles. R and THETA must have the same ,TYFPulYcp % length. The output Z is a matrix with one column for every (N,M) BD]o+96qP % pair, and one row for every (R,THETA) pair. K @:t6 % )/2TU]// % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike ~I~lb/ % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), -uhVw_qq# % with delta(m,0) the Kronecker delta, is chosen so that the integral OO,EUOh-T: % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, =hI;5KF % and theta=0 to theta=2*pi) is unity. For the non-normalized $)6M@S % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. \pP1k.~UnC % Qx_N,1>S % The Zernike functions are an orthogonal basis on the unit circle. pA_e{P/ % They are used in disciplines such as astronomy, optics, and z&jASL % optometry to describe functions on a circular domain. O&VA79\UO % 8CH9&N5W5t % The following table lists the first 15 Zernike functions. ' hdLQ\J % P=s3&NDD % n m Zernike function Normalization joNV4v"=` % -------------------------------------------------- g?cxqC< % 0 0 1 1 DwWm(8&6;} % 1 1 r * cos(theta) 2 K;>9K'n % 1 -1 r * sin(theta) 2 Fw#1?/K~ % 2 -2 r^2 * cos(2*theta) sqrt(6) 0+.<BOcW5 % 2 0 (2*r^2 - 1) sqrt(3) lB!M;2^)X % 2 2 r^2 * sin(2*theta) sqrt(6) W[>qiYf^b % 3 -3 r^3 * cos(3*theta) sqrt(8) %:OX^^i; % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) 5s>>]
.% % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) Rh)%; % 3 3 r^3 * sin(3*theta) sqrt(8) 9Q7342 % 4 -4 r^4 * cos(4*theta) sqrt(10) #wkSru&LS % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) LX =cx$K % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) ;3%Y@FS@ % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) vTL/% SJ8 % 4 4 r^4 * sin(4*theta) sqrt(10)
u_FN'p=. % -------------------------------------------------- r>sXvzv % #CW{y?= % Example 1: $
% B % t%@u)b p % % Display the Zernike function Z(n=5,m=1) Y)#,6\=U % x = -1:0.01:1; !JVv`YN % [X,Y] = meshgrid(x,x); 1{1mL-I; % [theta,r] = cart2pol(X,Y); +I}!)$/ % idx = r<=1; `\/\C[Gg % z = nan(size(X)); *nv^s % z(idx) = zernfun(5,1,r(idx),theta(idx)); p1T0FBV
L % figure 2+*o^`%4P % pcolor(x,x,z), shading interp vN~joQ=d % axis square, colorbar 43~v1pf{! % title('Zernike function Z_5^1(r,\theta)') -M4VC^_ % ~(=5`9 % Example 2: ID<[=es6 % S,a:H*Hf % % Display the first 10 Zernike functions EiyHZ % x = -1:0.01:1; 90ov[|MkM % [X,Y] = meshgrid(x,x); h${=gSJc % [theta,r] = cart2pol(X,Y); (`R
heEg@f % idx = r<=1; -"XHN=H % z = nan(size(X)); L=WKqRa>4 % n = [0 1 1 2 2 2 3 3 3 3]; fwa*|y; % m = [0 -1 1 -2 0 2 -3 -1 1 3]; ofs Lx6Po % Nplot = [4 10 12 16 18 20 22 24 26 28]; sLSH`Xy?5 % y = zernfun(n,m,r(idx),theta(idx)); -MORd{GF % figure('Units','normalized') /J(~NGT % for k = 1:10 #vAqqAS`, % z(idx) = y(:,k); =Q6JXp % subplot(4,7,Nplot(k)) M-e|$'4u % pcolor(x,x,z), shading interp 'aS: Azb % set(gca,'XTick',[],'YTick',[]) 6_:KFqc W % axis square _<l)4A3rS % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) 2(P<TP._E % end ?=HoU3 % Wq?vAnLbk % See also ZERNPOL, ZERNFUN2. ,L-V?B(UQ zy|h1.gd B3I0H6O % Paul Fricker 11/13/2006 O(:/&`) oxJAI4{y
4 y(Em+YTD D8{f7{nY !wZIXpeL % Check and prepare the inputs: X +/^s) % ----------------------------- Pj5:=d8z( if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) 4E$d"D5]>p error('zernfun:NMvectors','N and M must be vectors.') `1#Z9&bO end ']Z%6_WF 7Jpq7; "
BU4\QF- if length(n)~=length(m) 162Dj$ error('zernfun:NMlength','N and M must be the same length.') R'oGsaPB2 end `H9!Z$7G >x
]{cb/m sWi4+PAM0 n = n(:); &4*f28 s m = m(:); 4.>y[_vu if any(mod(n-m,2)) i1 GQ=@ error('zernfun:NMmultiplesof2', ... #E#@6ZomT 'All N and M must differ by multiples of 2 (including 0).') f9O_M1=|lo end ^,J>=>,1\ 1k{H,p7 Fw^^sB if any(m>n) "
^!=e72 error('zernfun:MlessthanN', ... M7YbRl 'Each M must be less than or equal to its corresponding N.') G}aM~, v end Ml)<4@ MFipXE! hb>uHUb& if any( r>1 | r<0 ) c4bv Jy8 error('zernfun:Rlessthan1','All R must be between 0 and 1.') V}JBv$+ko end ]1I-e2Q-J X9rao n (R9"0WeF if ( ~any(size(r)==1) ) || ( ~any(size(theta)==1) ) (aB:P03 error('zernfun:RTHvector','R and THETA must be vectors.') L:.Rv0XT end SjcX|=S \7e4t j_b/66JyN r = r(:); 4I.)>+8V theta = theta(:); }s8xr> length_r = length(r); ('.I)n if length_r~=length(theta) C\0,D9 error('zernfun:RTHlength', ... jPg[LZQ' 'The number of R- and THETA-values must be equal.') $-\%%n0>6 end |:`)sx3@# ciW;sK8 <Rz[G+0S= % Check normalization: X@7:FzU9 % -------------------- nd5.Py$ if nargin==5 && ischar(nflag) 6}*4co isnorm = strcmpi(nflag,'norm'); CM t$) if ~isnorm 8A'SMJi error('zernfun:normalization','Unrecognized normalization flag.') U?Vik end t{Ks}9B else SXV2Y- isnorm = false; C\ 34R end )[=C@U eUD 5V qr~zTBT]
E %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% y"H(F,(N % Compute the Zernike Polynomials A>*#Nw5L %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Q{
{= EV;"]lC9 d^"|ESQEU % Determine the required powers of r: 4UN|`'c % ----------------------------------- &C#?&AQ m_abs = abs(m); ~b[5}_L=> rpowers = []; kAW2vh for j = 1:length(n) Ze?H rpowers = [rpowers m_abs(j):2:n(j)]; %xC}#RDf end zXe]P(p< rpowers = unique(rpowers); tNAmA `J;g~#/k nr&9\lG]G % Pre-compute the values of r raised to the required powers, '1Ex{$Yk % and compile them in a matrix:
9q2x} % ----------------------------- /KlSI<T@ if rpowers(1)==0 mw83 pU6 rpowern = arrayfun(@(p)r.^p,rpowers(2:end),'UniformOutput',false); [9yy<Z5 rpowern = cat(2,rpowern{:}); M0]J`fL@ rpowern = [ones(length_r,1) rpowern]; mlz|KI~\F; else hF1Lj=x rpowern = arrayfun(@(p)r.^p,rpowers,'UniformOutput',false); Z0M|Bv9_ rpowern = cat(2,rpowern{:}); l?HC-_Pbh end r4]hcoU C`8.8 Lv #}Gm % Compute the values of the polynomials: d[p?B-7% % -------------------------------------- j% '~l#nw y = zeros(length_r,length(n)); JRDIGS_~ for j = 1:length(n)
$;)A:*e s = 0:(n(j)-m_abs(j))/2; Zy>y7O(, pows = n(j):-2:m_abs(j); ~hT(uxU/ for k = length(s):-1:1 x.
/WP~I p = (1-2*mod(s(k),2))* ... o\nFSGkn prod(2:(n(j)-s(k)))/ ... gi8f)MNP?~ prod(2:s(k))/ ... (?P\;yDG prod(2:((n(j)-m_abs(j))/2-s(k)))/ ... 1Q$/L+uJ5 prod(2:((n(j)+m_abs(j))/2-s(k))); 2HDWlUTNVO idx = (pows(k)==rpowers); .gCun_td# y(:,j) = y(:,j) + p*rpowern(:,idx); = @ 1{LF; end t;t;+M|W Iz!]LW if isnorm |doG}C y(:,j) = y(:,j)*sqrt((1+(m(j)~=0))*(n(j)+1)/pi); )t$-/8 end gbFHH,@ end M4t:)!dji? % END: Compute the Zernike Polynomials '.7ER %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% ZD<e$PxxCd RZ?abE8 *tl; 0<n % Compute the Zernike functions: t1!>EI` % ------------------------------ Wyb+K)Tg idx_pos = m>0; u_Xp\RJ idx_neg = m<0; w|-m*v
. *~zB { W O'nW z = y; 0
.ck!"h} if any(idx_pos) _I0=a@3 z(:,idx_pos) = y(:,idx_pos).*sin(theta*m(idx_pos)'); Rvd'uIJ end [u^~ND ' if any(idx_neg) 8,)<,g-/= z(:,idx_neg) = y(:,idx_neg).*cos(theta*m(idx_neg)'); p,3}A(> end ~8)l/I=`); pzT`.#N:M zuJ@@\75 % EOF zernfun :bqUA(k
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