| 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, 0U%Xm[: 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, x~z_,': 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? -Uri|^t 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? SHwRX?
B| O)1E$#~ j %H`0 F3Dt7q C38%H function z = zernfun(n,m,r,theta,nflag) xD4$0Ppu %ZERNFUN Zernike functions of order N and frequency M on the unit circle. +aj^Cs1$ % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N `.[ 8$ % and angular frequency M, evaluated at positions (R,THETA) on the
$WR? % unit circle. N is a vector of positive integers (including 0), and =LK}9ViH % M is a vector with the same number of elements as N. Each element 4\HsU9x % k of M must be a positive integer, with possible values M(k) = -N(k) ^SAq^3^P! % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, 9T?64t<Ju % and THETA is a vector of angles. R and THETA must have the same c|Y!c!9F % length. The output Z is a matrix with one column for every (N,M) {@45?L(' % pair, and one row for every (R,THETA) pair. 2f^-~dz % Z7KXWu+6`m % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike AEqq1A % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), Fg4@On[,i % with delta(m,0) the Kronecker delta, is chosen so that the integral &XtRLtgS % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, n/ AW?' % and theta=0 to theta=2*pi) is unity. For the non-normalized ).Gd1pE % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. lJ&y&N<O % ]4o?BkL % The Zernike functions are an orthogonal basis on the unit circle. A="fj % They are used in disciplines such as astronomy, optics, and l&Q!mU} % optometry to describe functions on a circular domain. 9~~UM<66W % h0lu!m#\_ % The following table lists the first 15 Zernike functions. ;`X~ k|7K % M~p=#V1D % n m Zernike function Normalization $rB6< % -------------------------------------------------- 3S;N(A4 % 0 0 1 1 :".w{0l@ % 1 1 r * cos(theta) 2 "{ FoA3g| % 1 -1 r * sin(theta) 2 PQ3h\CL1n % 2 -2 r^2 * cos(2*theta) sqrt(6) 4.'JLArw % 2 0 (2*r^2 - 1) sqrt(3) <m]wi7 % 2 2 r^2 * sin(2*theta) sqrt(6) ;(S|cm'>} % 3 -3 r^3 * cos(3*theta) sqrt(8) fGTOIi@# % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) (bvoF5% % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) 02pplDFsM % 3 3 r^3 * sin(3*theta) sqrt(8) AerFgQiS % 4 -4 r^4 * cos(4*theta) sqrt(10) SX_4=^ % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) az2Xch] % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) ="dDA/,$VS % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) \igaQ\~ % 4 4 r^4 * sin(4*theta) sqrt(10) eO[c l B % -------------------------------------------------- lkwh'@s. % Up|f=@= % Example 1: 7kd|K
b( % V.2[ F|P;3 % % Display the Zernike function Z(n=5,m=1) }dKLMNqPA % x = -1:0.01:1; bjzx!OCpV % [X,Y] = meshgrid(x,x); R&Ci/ % [theta,r] = cart2pol(X,Y); T VeJ6 % idx = r<=1; 9^\hmpP@D % z = nan(size(X)); ,C:o`fQ\ % z(idx) = zernfun(5,1,r(idx),theta(idx)); ve-8*Xa % figure /[?Jylj % pcolor(x,x,z), shading interp m[rL\](- % axis square, colorbar KTv4< c] % title('Zernike function Z_5^1(r,\theta)') LS6ry,D"7 % >3P9 i ;W % Example 2:
tT-=hDw % U&Ab#m; % % Display the first 10 Zernike functions ?d5h9}B % x = -1:0.01:1; hVf^ % [X,Y] = meshgrid(x,x); 5~s{N % [theta,r] = cart2pol(X,Y); ^*>n4U % idx = r<=1; aDveU)]=1 % z = nan(size(X)); ]/44Ygz/ % n = [0 1 1 2 2 2 3 3 3 3]; PpFsp( )x % m = [0 -1 1 -2 0 2 -3 -1 1 3]; afUTAP@ % Nplot = [4 10 12 16 18 20 22 24 26 28]; Rcf=J){D6 % y = zernfun(n,m,r(idx),theta(idx)); M=[th % figure('Units','normalized') (yGQa5v % for k = 1:10 9-93aC.|} % z(idx) = y(:,k); j ug'g % subplot(4,7,Nplot(k)) L|J~9FM % pcolor(x,x,z), shading interp gn.Ol/6D % set(gca,'XTick',[],'YTick',[]) GoD ?K C % axis square 9U'[88 % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) rS,j;8D- % end -[$&s FD % blp=Hk % See also ZERNPOL, ZERNFUN2. J7n5Ps\M -l JYr/MSL -|[~sj-p % Paul Fricker 11/13/2006 ETm]o
c'rd $ B{PLIisc _:%U_U Qi:j)uDW % Check and prepare the inputs: l5HWZs^ % ----------------------------- _[JkJwPTx if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) QkE,T0,/?h error('zernfun:NMvectors','N and M must be vectors.') n ,1tD end 6|oWaA\gI :t5uDKZ_j) $',3Pv if length(n)~=length(m) !sG"n&uZq error('zernfun:NMlength','N and M must be the same length.') h!Y?SO.b end 2&x7W* PGY9*0n O#G|
~'., n = n(:); ;dOs0/UM& m = m(:); >2Ca5C if any(mod(n-m,2)) 6l[G1KkV error('zernfun:NMmultiplesof2', ... r{Z[xWIX 'All N and M must differ by multiples of 2 (including 0).') %YCd%lAe, end 5m`[MBt2g T<M?PlED xD0NZ~w% if any(m>n) pns+y error('zernfun:MlessthanN', ... :MBS>owR 'Each M must be less than or equal to its corresponding N.') R'Eq:Rv~;^ end _uJVuCc DM'qNgB7 >-zkB)5<,# if any( r>1 | r<0 ) jN {Zw* error('zernfun:Rlessthan1','All R must be between 0 and 1.') yZ~b+=UM end 1I
\tu j8c6[ih s ^3[W0hL if ( ~any(size(r)==1) ) || ( ~any(size(theta)==1) ) Uz
$ @(C error('zernfun:RTHvector','R and THETA must be vectors.') JT#7yetk' end J&_3VKrN mmcdtVe h"8QeX:(( r = r(:); pI5_Hg theta = theta(:); X(b1/lzA length_r = length(r); ]4GZ'&m} if length_r~=length(theta) 9t}J|09i error('zernfun:RTHlength', ... wibwyzo 'The number of R- and THETA-values must be equal.') 4(8<w cL end 9fMSAB+c% 117c,yM0 9#fp_G;= % Check normalization: K9*IA@xL % -------------------- |i u2&p > if nargin==5 && ischar(nflag) T g{UK isnorm = strcmpi(nflag,'norm'); W]@6=OpH if ~isnorm %Gu][_.L error('zernfun:normalization','Unrecognized normalization flag.') 2!idy]vy_ end hbH#Co~o4# else {( dP isnorm = false; .OV-`TNWj end ;le0QA
Pf ,m:6qdN o"\{OX %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% `1q|F9D % Compute the Zernike Polynomials M=6G:HHY %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% ?^F5(B[+Y 'QnW9EHLF 8(^
,r#Gy % Determine the required powers of r: V pH|R % ----------------------------------- I5Q~T5Ar m_abs = abs(m); ZBC@xM&- rpowers = []; _{mJ.1)V; for j = 1:length(n) D$mf5G & rpowers = [rpowers m_abs(j):2:n(j)]; R~c IT:i end ,0h3x$l) rpowers = unique(rpowers); #?Wo <]i @'Q%Jc( E^82==R % Pre-compute the values of r raised to the required powers, 9':/Sab:7v % and compile them in a matrix: Op90NZI#K % ----------------------------- HGb.656r if rpowers(1)==0 ;&q]X]bJ rpowern = arrayfun(@(p)r.^p,rpowers(2:end),'UniformOutput',false); 4]]b1^vVj rpowern = cat(2,rpowern{:}); .5NZf4:C rpowern = [ones(length_r,1) rpowern]; ]Cr]Pvab{ else Bqp&2zg)@ rpowern = arrayfun(@(p)r.^p,rpowers,'UniformOutput',false); `;e^2 rpowern = cat(2,rpowern{:}); Q<C@KBiVE end MorW\7-} [*tU}9 mgxz1d % Compute the values of the polynomials: \wFhTJY % -------------------------------------- cT I,1U y = zeros(length_r,length(n)); ^ISQ{M#_ for j = 1:length(n) }.OxJ=M s = 0:(n(j)-m_abs(j))/2; K: 4P;ApI pows = n(j):-2:m_abs(j); ^h`!f vyH for k = length(s):-1:1 T6;>O`B.r p = (1-2*mod(s(k),2))* ... \3M1.Q4$Gr prod(2:(n(j)-s(k)))/ ... O8iu+}]/6 prod(2:s(k))/ ... 6Z$b?A3zM prod(2:((n(j)-m_abs(j))/2-s(k)))/ ... K/~Y!?:Jr prod(2:((n(j)+m_abs(j))/2-s(k))); We|-5 idx = (pows(k)==rpowers); FGDw;lEa9[ y(:,j) = y(:,j) + p*rpowern(:,idx); ')r D?Z9 ^ end x)d2G6x W;91H'`?H if isnorm H8(C>w-' y(:,j) = y(:,j)*sqrt((1+(m(j)~=0))*(n(j)+1)/pi); y.
Tct. end V!\n3i?i end /m;O;2" % END: Compute the Zernike Polynomials 8.PXTOhVL %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% O-?z' @5cI b5[f 5 q;IhLBl' % Compute the Zernike functions: A<a2TXcIE3 % ------------------------------ 7G?Ia%u idx_pos = m>0; O3!Ouh& idx_neg = m<0; py}.00it E*h0#m|) UP5%C; z = y; AUu5g if any(idx_pos) Ja^7$WY z(:,idx_pos) = y(:,idx_pos).*sin(theta*m(idx_pos)'); S[ws0Y60 end Wn2Ny jX if any(idx_neg) 7=L:m7T z(:,idx_neg) = y(:,idx_neg).*cos(theta*m(idx_neg)'); VyRW ' end (R,NV3m?w ,>:XE@xcp ?&{S~[;l % EOF zernfun @"jmI&hYn
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