| 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, Uc/%4Gx 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, __a9}m4i7x 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? n4ISHxM 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? g3y44GCV {5,CW Dx8^V%b AojX)_"z ].$N@tC function z = zernfun(n,m,r,theta,nflag) 'RPe5 vB %ZERNFUN Zernike functions of order N and frequency M on the unit circle. ej0q*TH. % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N !$O +M# % and angular frequency M, evaluated at positions (R,THETA) on the Wg#>2)> % unit circle. N is a vector of positive integers (including 0), and Z*k}I{0,- % M is a vector with the same number of elements as N. Each element RSp=If+4 % k of M must be a positive integer, with possible values M(k) = -N(k) 5nk]{ G> V % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, ETmfy}V8 % and THETA is a vector of angles. R and THETA must have the same RxAZ<8T_ % length. The output Z is a matrix with one column for every (N,M) z 6p.{M % pair, and one row for every (R,THETA) pair. (u~@@d" % s8R.?mhH= % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike &n['#7 <(! % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), 1%>/%eyn5 % with delta(m,0) the Kronecker delta, is chosen so that the integral Ygg+*z
% of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, WzF/wzR % and theta=0 to theta=2*pi) is unity. For the non-normalized >1W)J3 % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. f-
_~rQ % pJV<#<#Z % The Zernike functions are an orthogonal basis on the unit circle. ;XANITV % They are used in disciplines such as astronomy, optics, and gx3arVa % optometry to describe functions on a circular domain. 6L8wsz CW % Z[ys>\_To % The following table lists the first 15 Zernike functions. p2\@E}
z % y<kW2<? % n m Zernike function Normalization Fvg>>HVu % -------------------------------------------------- oB+drDp8U % 0 0 1 1 HG{OkDx]fl % 1 1 r * cos(theta) 2 oPl^tzO % 1 -1 r * sin(theta) 2 G/b
$cO} % 2 -2 r^2 * cos(2*theta) sqrt(6) wD4Kil=v % 2 0 (2*r^2 - 1) sqrt(3) >Ka}v:E % 2 2 r^2 * sin(2*theta) sqrt(6) I_\j05 % 3 -3 r^3 * cos(3*theta) sqrt(8) VTS8IXz % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) ]e!9{\X,* % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) rQCj^=cf;~ % 3 3 r^3 * sin(3*theta) sqrt(8) \Gg6&:Ua % 4 -4 r^4 * cos(4*theta) sqrt(10) ).5$c0`U& % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) IvO#tI % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) \s<L2uRj % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) 5*C#~gd&F % 4 4 r^4 * sin(4*theta) sqrt(10) 4'[/gMUkw % -------------------------------------------------- O(#DaFJv % ^i:%0"[*^i % Example 1: 4YMX;W % kocgPO5 % % Display the Zernike function Z(n=5,m=1) o-c.D=~ % x = -1:0.01:1; e-Mei7{% % [X,Y] = meshgrid(x,x); D5^wT>3> % [theta,r] = cart2pol(X,Y); "&W80,O3 % idx = r<=1; WWZ`RY % z = nan(size(X)); v;1<K@UT % z(idx) = zernfun(5,1,r(idx),theta(idx)); ~qT5F)$B- % figure Jpm=V*P % pcolor(x,x,z), shading interp DxoW,GW % axis square, colorbar 54r/s#|-3 % title('Zernike function Z_5^1(r,\theta)') ir!/{IQx % 6fY-DqF! % Example 2: (l}W\iB'd % F!ZE4S_ % % Display the first 10 Zernike functions ~Z-o2+xA % x = -1:0.01:1; /-s-W<S[ % [X,Y] = meshgrid(x,x); F=EG#<@u % [theta,r] = cart2pol(X,Y); Ce_k&[AJF % idx = r<=1; ip8%9fG\> % z = nan(size(X)); wwaw|$ % n = [0 1 1 2 2 2 3 3 3 3]; cao=O
\Y7 % m = [0 -1 1 -2 0 2 -3 -1 1 3]; UB^OMB-W.m % Nplot = [4 10 12 16 18 20 22 24 26 28]; Y].,}}9k % y = zernfun(n,m,r(idx),theta(idx)); iC2``[m" % figure('Units','normalized') 4 ))Z Bq? % for k = 1:10 9lqH % z(idx) = y(:,k); OGcq]ue % subplot(4,7,Nplot(k)) bY&!d. % pcolor(x,x,z), shading interp LT[g
+zGB % set(gca,'XTick',[],'YTick',[]) \w#)uYK{i_ % axis square <
#FxI % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) z;iNfs0i$ % end ]sLdz^E3D % y90wLU9f % See also ZERNPOL, ZERNFUN2. C2
4"H|D #;D@`.#\ [|A;{F# % Paul Fricker 11/13/2006 z_f^L %J0 O#MaZ.= "o)jB~:L i+90##4<? 7D&O5Z=%+ % Check and prepare the inputs: Ua%;hI)j$ % ----------------------------- \Vb|bw'e( if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) QZ&
4W error('zernfun:NMvectors','N and M must be vectors.') tJ$gH; end %\^VxM { k>T*/ ,J(shc_F if length(n)~=length(m) r(j :C%?}C error('zernfun:NMlength','N and M must be the same length.') P](/5KrK end :lW8f~! otA'+4\ ^u(-v/D9 n = n(:); [>D5(O m = m(:); R0~w F> if any(mod(n-m,2)) +wp !hk&C5 error('zernfun:NMmultiplesof2', ... ?U+nR/H:6 'All N and M must differ by multiples of 2 (including 0).') (<2!^v0.M end A01PEVd@A >N~orSw% pz= /A if any(m>n) RiG]-K: error('zernfun:MlessthanN', ... NY?pvb 'Each M must be less than or equal to its corresponding N.') f cnv[B..{ end /Z~5bb( 068DC_ wEZieHw if any( r>1 | r<0 ) ' ""s%C+ error('zernfun:Rlessthan1','All R must be between 0 and 1.') L"RE[" m end ?f= ~Pn+ ;b}cn!U] .On3ZN if ( ~any(size(r)==1) ) || ( ~any(size(theta)==1) ) !Qq~lAJO; error('zernfun:RTHvector','R and THETA must be vectors.') .=N ?;i end :}-VLp4b Th
X6e SohNk9u[8 r = r(:); r:M0#
2 theta = theta(:); 4C[kj length_r = length(r); Dtox/ ," if length_r~=length(theta) eus@;l* error('zernfun:RTHlength', ... xb2j
|KY7 'The number of R- and THETA-values must be equal.') WMS~Bk+! end 5 qMP u|A .qLXjU 7+Er}y> % Check normalization: 1 F&}e&}c % -------------------- 7^;-[?l
if nargin==5 && ischar(nflag) XMzQ8|] isnorm = strcmpi(nflag,'norm'); ?rY+,nQP if ~isnorm Wcbm,O4u error('zernfun:normalization','Unrecognized normalization flag.') 'U,\5jj'Y end 7)RRCsn else /IlO isnorm = false; qOAP_\@T end XqGa]/;} OepQ Z|2 n\< uT1n %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% cT@H49#uB % Compute the Zernike Polynomials V/xjI< | |