| 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, 'Z\{D*=V8 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, oz%h)#; 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? OYBotk]{1 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? myD{sE2A -&trk 4$%`Qh>yA ewo*7j4* %v]7BV^%6 function z = zernfun(n,m,r,theta,nflag) :tKbz
nd/ %ZERNFUN Zernike functions of order N and frequency M on the unit circle. hgj CXl % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N \C|;F % and angular frequency M, evaluated at positions (R,THETA) on the Ip>^O/}$1 % unit circle. N is a vector of positive integers (including 0), and N%O[ % M is a vector with the same number of elements as N. Each element Y.E?;iS % k of M must be a positive integer, with possible values M(k) = -N(k) 5+`=t07^et % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, gk"mr_03 % and THETA is a vector of angles. R and THETA must have the same bKYY{V55 % length. The output Z is a matrix with one column for every (N,M) GUKDhg,W % pair, and one row for every (R,THETA) pair. 9^oo-,Su_ % :ezA+=ENg % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike F\JLbY{x] % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), O-Dc[t% % with delta(m,0) the Kronecker delta, is chosen so that the integral !2(.$}E % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, O8gfiQqF& % and theta=0 to theta=2*pi) is unity. For the non-normalized NzAQ@E2d: % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. QS\Uq(Ja\ % \ZqK\= % The Zernike functions are an orthogonal basis on the unit circle. *h2`^Z % They are used in disciplines such as astronomy, optics, and D^nxtuT* % optometry to describe functions on a circular domain. [4Y[?)7 % "rVU4F) % The following table lists the first 15 Zernike functions. Y7-*2"! % 7 xUE,)? % n m Zernike function Normalization l7ZB3' % -------------------------------------------------- M]1; % 0 0 1 1 fO#?k<p % 1 1 r * cos(theta) 2 NJ<N %hcjK % 1 -1 r * sin(theta) 2 D
0 % 2 -2 r^2 * cos(2*theta) sqrt(6) 3i6h"Wu`n % 2 0 (2*r^2 - 1) sqrt(3) =m~ruZ/ % 2 2 r^2 * sin(2*theta) sqrt(6) 6>s=CiZB % 3 -3 r^3 * cos(3*theta) sqrt(8) F% }7cm2 % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) "i&fp:E0 % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) "tKNlHBu' % 3 3 r^3 * sin(3*theta) sqrt(8)
F,zG;_ % 4 -4 r^4 * cos(4*theta) sqrt(10) :v_w!+,/ % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) zb>;?et;) % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) C*a,<` % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) #J\s%60pt % 4 4 r^4 * sin(4*theta) sqrt(10) ?;_H{/)m % -------------------------------------------------- *(icR % -rO*7HO % Example 1: X CzXS. % h<)yJh % % Display the Zernike function Z(n=5,m=1) bTiBmS % x = -1:0.01:1; >{b3>s~T % [X,Y] = meshgrid(x,x); y=#j`MH{> % [theta,r] = cart2pol(X,Y); .wD>Gs{sH[ % idx = r<=1; \KCWYi] % z = nan(size(X)); z#RuwB+ % z(idx) = zernfun(5,1,r(idx),theta(idx)); T!(sZf % figure 8]HY. $E % pcolor(x,x,z), shading interp pD[pTMG@$ % axis square, colorbar (V!0'9c % title('Zernike function Z_5^1(r,\theta)') ~~@y_e[N#l % -qfnUh % Example 2: 2
^oGwx @ % pu#[pa
% % Display the first 10 Zernike functions fQO
""qh % x = -1:0.01:1; *y?[<2"$ % [X,Y] = meshgrid(x,x); t| _{;!^
% [theta,r] = cart2pol(X,Y); a5)JkC % idx = r<=1; @gEr+O1K( % z = nan(size(X)); &1l~&,, % n = [0 1 1 2 2 2 3 3 3 3]; ~@@
Z|w % m = [0 -1 1 -2 0 2 -3 -1 1 3]; "Vx6 #u@} % Nplot = [4 10 12 16 18 20 22 24 26 28]; a(f(R&-:$Y % y = zernfun(n,m,r(idx),theta(idx)); \+9;!VWhl % figure('Units','normalized') Td& | |