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, Xn:5pd;?B6 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, *=G~26*!V 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? ,_SE!iL 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? ?a)X)#lQ 9gWR djK: S
^5EG;[ <HYK9{Q Oe#*- function z = zernfun(n,m,r,theta,nflag) >.sdLA Si %ZERNFUN Zernike functions of order N and frequency M on the unit circle. Z]L_{=* % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N Z\1*g k % and angular frequency M, evaluated at positions (R,THETA) on the cXcrb4IKD % unit circle. N is a vector of positive integers (including 0), and R\i8O^[ % M is a vector with the same number of elements as N. Each element o<1a]M| % k of M must be a positive integer, with possible values M(k) = -N(k) %P3|#0yg0 % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, 9^yf'9S1 % and THETA is a vector of angles. R and THETA must have the same 0cGO*G2Xr % length. The output Z is a matrix with one column for every (N,M) Z}X oWT2f % pair, and one row for every (R,THETA) pair. <[*%d~92z % f&=WgITa % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike Kivr)cIG % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), NY(z3G % with delta(m,0) the Kronecker delta, is chosen so that the integral *s=jKV# % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, G`;YB % and theta=0 to theta=2*pi) is unity. For the non-normalized 3bWYRW % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. -'!K(" % +ConK>; % The Zernike functions are an orthogonal basis on the unit circle. a9f!f %9 % They are used in disciplines such as astronomy, optics, and MC'2;, % optometry to describe functions on a circular domain. (ncm]W % Q4H(JD1f) % The following table lists the first 15 Zernike functions. Xl/SDm_p % vHydqFi 9 % n m Zernike function Normalization [ClDKswq % -------------------------------------------------- lwVo%- % 0 0 1 1 XJ$mRh0`K % 1 1 r * cos(theta) 2 hXAgT!ZD % 1 -1 r * sin(theta) 2 `/e
EdqT % 2 -2 r^2 * cos(2*theta) sqrt(6) sY-
]
Q % 2 0 (2*r^2 - 1) sqrt(3) >$/<~j] % 2 2 r^2 * sin(2*theta) sqrt(6) 5YV3pFz$) % 3 -3 r^3 * cos(3*theta) sqrt(8) Bd++G'FZ % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) sxK|0i}6 % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) og?>Q i Tr % 3 3 r^3 * sin(3*theta) sqrt(8) l* ap$1' % 4 -4 r^4 * cos(4*theta) sqrt(10) a1Kh % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) :cE6-Fv % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) Y^Y1re+} % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) }EMds3< % 4 4 r^4 * sin(4*theta) sqrt(10) xj!G9x<! % -------------------------------------------------- ELvP<Ny} % qH=<8Iu % Example 1: &s{" Vc9] %
/N8>>g % % Display the Zernike function Z(n=5,m=1) #$dEg % x = -1:0.01:1; Lu][0+- % [X,Y] = meshgrid(x,x); w7d<Ky_C % [theta,r] = cart2pol(X,Y); uHQf <R$: % idx = r<=1; $b CN;yE % z = nan(size(X)); h>a/3a$g % z(idx) = zernfun(5,1,r(idx),theta(idx)); xwJ.cy % figure G u4mP % pcolor(x,x,z), shading interp Sb|9U8h % axis square, colorbar au;ZAXM| % title('Zernike function Z_5^1(r,\theta)') Ovhd%qV;Y % ^o8o % Example 2: sX
c|++ % K2o\+t % % Display the first 10 Zernike functions 6rll0c~ % x = -1:0.01:1; lP;X=X> % [X,Y] = meshgrid(x,x); n5U-D0/Q % [theta,r] = cart2pol(X,Y); [-p?gyl % idx = r<=1; >D5WAQ>b % z = nan(size(X)); \'Z^rjB % n = [0 1 1 2 2 2 3 3 3 3]; !uc"|S? % m = [0 -1 1 -2 0 2 -3 -1 1 3]; 2FxrjA % Nplot = [4 10 12 16 18 20 22 24 26 28]; DX b=Ku % y = zernfun(n,m,r(idx),theta(idx)); L5RBe % figure('Units','normalized') "q]r{0 % for k = 1:10 =U`9_]~1c@ % z(idx) = y(:,k); (Do](C % subplot(4,7,Nplot(k)) ls ,;ozU % pcolor(x,x,z), shading interp y?-zQs0 % set(gca,'XTick',[],'YTick',[]) 3*C|"|lJ % axis square LDgGVl % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) )OE!vA % end *p.70,5, % *>,#'C2 % See also ZERNPOL, ZERNFUN2. Z[GeU>?P HxnWM\ p .Gcs/PN % Paul Fricker 11/13/2006 ',l}$]y5 &57s//PrX g5[r!XO +\s&v! qZB}}pM# % Check and prepare the inputs: ><DXT nt'x % ----------------------------- tg"NWp6 if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) ZQN%!2 error('zernfun:NMvectors','N and M must be vectors.') P/Zp3O H end py%_XL=w, mIYM+2p %|o2d&i if length(n)~=length(m) =2& | |