| 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, lIhP\:;S& 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, pH9xyN[:a 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? lwSZpS 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? yf4I<v$y \=1$$EDS9 CE5A^,EsB NZb}n`: kuq&8f~! function z = zernfun(n,m,r,theta,nflag) Q6 oM$qiM %ZERNFUN Zernike functions of order N and frequency M on the unit circle. ~:JoKm`vU % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N Vb @lK~ % and angular frequency M, evaluated at positions (R,THETA) on the Sj'Iz # % unit circle. N is a vector of positive integers (including 0), and G+~f % M is a vector with the same number of elements as N. Each element v:F_!Q % k of M must be a positive integer, with possible values M(k) = -N(k) A:$4cacu9 % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, eG_@WLxwD % and THETA is a vector of angles. R and THETA must have the same P:#KBF;a % length. The output Z is a matrix with one column for every (N,M) wPE\?en % pair, and one row for every (R,THETA) pair. !qu/m B % T?g%I % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike ^j!2I&h1 % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), P @Jo[J< % with delta(m,0) the Kronecker delta, is chosen so that the integral c4f3Dr'xw % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, ^7Rc\ % and theta=0 to theta=2*pi) is unity. For the non-normalized BHu%x|d % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. B"Ma<"HU % rD;R9b"J % The Zernike functions are an orthogonal basis on the unit circle. .fgVzDR|+ % They are used in disciplines such as astronomy, optics, and EJW}&e/ % optometry to describe functions on a circular domain. XiL[1JM
% gs"w
0[$ % The following table lists the first 15 Zernike functions. gy`WBg(7x % ew.jsa`TrW % n m Zernike function Normalization gF>t+"+x % -------------------------------------------------- ^~1Z"kAnT % 0 0 1 1 j4:Xel/ % 1 1 r * cos(theta) 2 } *jmW P % 1 -1 r * sin(theta) 2 Bwc_N.w?3 % 2 -2 r^2 * cos(2*theta) sqrt(6) [gDl<6a#4 % 2 0 (2*r^2 - 1) sqrt(3) %M*2 j%6 % 2 2 r^2 * sin(2*theta) sqrt(6) ElA(1o|9I % 3 -3 r^3 * cos(3*theta) sqrt(8) dw>1Ut{"3 % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) oCxy(q'y % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) yBRYEqS+ % 3 3 r^3 * sin(3*theta) sqrt(8) /,,IM/(6^ % 4 -4 r^4 * cos(4*theta) sqrt(10) =[:pm) % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) vD^Uod1 % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) >}E % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) S}P rgw/ % 4 4 r^4 * sin(4*theta) sqrt(10) hb<cynY % -------------------------------------------------- FN/siw(?3 % gtnu/Q % Example 1: J(:y-U % 4(dgunP % % Display the Zernike function Z(n=5,m=1) n%6ba77 % x = -1:0.01:1; \beYb0(+ % [X,Y] = meshgrid(x,x); 7Bym? % [theta,r] = cart2pol(X,Y); 8shx7" % idx = r<=1; &^7(?C'u % z = nan(size(X)); R2A#2{+H % z(idx) = zernfun(5,1,r(idx),theta(idx)); \30rF]F`l % figure d2?#&d'aq % pcolor(x,x,z), shading interp bao"iv~z % axis square, colorbar 6 Nws>(Ij % title('Zernike function Z_5^1(r,\theta)') Qb5@e#
% N F,<^ u % Example 2: F/cA tT.M? % :Y|[?; % % Display the first 10 Zernike functions &3OV|ly] % x = -1:0.01:1; [a_o3 % [X,Y] = meshgrid(x,x); S%jW}v'; % [theta,r] = cart2pol(X,Y); &O5O@3:7] % idx = r<=1; U4[GA4DZ % z = nan(size(X)); q8!]x-5$6j % n = [0 1 1 2 2 2 3 3 3 3]; hEFOT]P4 % m = [0 -1 1 -2 0 2 -3 -1 1 3]; *L~?.9R % Nplot = [4 10 12 16 18 20 22 24 26 28]; 6 rWb2b % y = zernfun(n,m,r(idx),theta(idx));
7&dK_x,a % figure('Units','normalized') CQPq5/@Y4 % for k = 1:10 "A> _U<Y % z(idx) = y(:,k); e{H( % subplot(4,7,Nplot(k)) ~e&O?X % pcolor(x,x,z), shading interp \EXa 9X2 % set(gca,'XTick',[],'YTick',[]) + KaVvf % axis square ?AH B\S % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) %=Y=]g2 % end LJ K0WWch % !;4Hh)2 % See also ZERNPOL, ZERNFUN2. gquvVj1oT s\< @v7A 1Ko4O)L]& % Paul Fricker 11/13/2006 G)q;)n;*= aU@1j;se@ cwOa"]t} e<qfM&* o70] F % Check and prepare the inputs: ^ FM % ----------------------------- RL)~J4Y if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) cvQAo| error('zernfun:NMvectors','N and M must be vectors.') rHi4Pw{L end lwz\"8 _ds;:*N+qA %WC^aKfY if length(n)~=length(m) h?H|)a<^9 error('zernfun:NMlength','N and M must be the same length.') G{{M'1 end (AX$Svw M ziOpraj t 4VeXp6 n = n(:); (L1F],Au m = m(:); $}'(%\7" if any(mod(n-m,2)) .
:>e"D error('zernfun:NMmultiplesof2', ... 1{wbC) 'All N and M must differ by multiples of 2 (including 0).') @qYT/V*/ end
M%Ksyr9 ,p#r; O<O *Hi}FI if any(m>n) !.-u'6e
error('zernfun:MlessthanN', ... |fIyq}{7 'Each M must be less than or equal to its corresponding N.') m;A[2 6X end rLE+t(x(0 GwfC l{l MTN*{ug2: if any( r>1 | r<0 ) rL&Mq}7QK error('zernfun:Rlessthan1','All R must be between 0 and 1.') 3m9b end ^}{x).
oam;hmw qGX#(,E9; if ( ~any(size(r)==1) ) || ( ~any(size(theta)==1) ) $PI9vyS error('zernfun:RTHvector','R and THETA must be vectors.') 2gZ nrU end [qC0YM ,tcUJ}l 0~K&P#iR r = r(:); 9zS theta = theta(:); 1q@R04i length_r = length(r); (Zd(?">i if length_r~=length(theta) ~**x_ v error('zernfun:RTHlength', ... "*.N'J\ 'The number of R- and THETA-values must be equal.') D,R',(3 end A)V*faD 9(nq 4HvI 0?(uqjD: % Check normalization: <9piKtb|L % -------------------- dq`{fqGl if nargin==5 && ischar(nflag) H1 7I"5N isnorm = strcmpi(nflag,'norm'); ]@b9m if ~isnorm AFm9"mQrw error('zernfun:normalization','Unrecognized normalization flag.') vV*J;%MO end P"l'? ` else 5OtdB'UITd isnorm = false; tpC^68*F end Z/:F)c,x $+_1F`
7s#8-i %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% >X
eXd{$ % Compute the Zernike Polynomials -4sKB>b %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% V-@4s}zX DU$#tg}{ <n 06(9BF % Determine the required powers of r: :i4(cap&}F % ----------------------------------- d1/9
A-{ m_abs = abs(m); 7U_ob"`JV rpowers = []; ` =P_ed%&' for j = 1:length(n) oKCy,Ot< rpowers = [rpowers m_abs(j):2:n(j)]; ;nP(S`' end +(92}~RK rpowers = unique(rpowers); @$n
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]]l0B % Pre-compute the values of r raised to the required powers, P1T{5u!T % and compile them in a matrix: 3MFTP5~ % ----------------------------- U|x Hy+N if rpowers(1)==0 ThgJ
' rpowern = arrayfun(@(p)r.^p,rpowers(2:end),'UniformOutput',false); N+B!AK0. rpowern = cat(2,rpowern{:}); Ycspdl+(S$ rpowern = [ones(length_r,1) rpowern]; ]6[+tpx else GT6i9*tb# rpowern = arrayfun(@(p)r.^p,rpowers,'UniformOutput',false); (C#0
ML rpowern = cat(2,rpowern{:});
IPK1g3Z end vm_]X{80; 3PZ(Kn< k[ z yR % Compute the values of the polynomials: CvE^t#Bok % -------------------------------------- >Ti%Th, y = zeros(length_r,length(n)); BJWlx*U] for j = 1:length(n) ; Z7!BU s = 0:(n(j)-m_abs(j))/2; ~Yi4?B< pows = n(j):-2:m_abs(j); v$Fz^<Na for k = length(s):-1:1 aH?Ygzw p = (1-2*mod(s(k),2))* ... n19A>,m prod(2:(n(j)-s(k)))/ ... jaodcT0 prod(2:s(k))/ ... eG!ma` v prod(2:((n(j)-m_abs(j))/2-s(k)))/ ... } SWp~3P prod(2:((n(j)+m_abs(j))/2-s(k))); D^6iQW+.P idx = (pows(k)==rpowers); BLt58LYGX y(:,j) = y(:,j) + p*rpowern(:,idx); B
os`+Y end >fI\f <ez ;9mRumLG" if isnorm /X.zt
` y(:,j) = y(:,j)*sqrt((1+(m(j)~=0))*(n(j)+1)/pi); UHvA43 end V&:x+swt end te-xhJ&K % END: Compute the Zernike Polynomials MWA,3I\. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %K|f,w=m k+-?b(z)$ RVttk )Ny % Compute the Zernike functions: (KyOo,a % ------------------------------ 7`J2/( idx_pos = m>0; GkI'. idx_neg = m<0; #0b:5.vy :cWU,V _MTZuhY z = y; ydYsmTr if any(idx_pos) InbB2l4G z(:,idx_pos) = y(:,idx_pos).*sin(theta*m(idx_pos)'); 4jebx
jZ end hQ<7k'V if any(idx_neg) Eqz|eS*6 z(:,idx_neg) = y(:,idx_neg).*cos(theta*m(idx_neg)'); yjL+1_"B end %AA&n*m A/I\MN| z6@8IszU % EOF zernfun (Q=o9o:b
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