| 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, H^ds<I<) 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, CWdpF>En 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?
nQ +$ 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? u!CcTE* 2p %j@O h[ cqa k^@dDLr" mE"(d*fe' function z = zernfun(n,m,r,theta,nflag) #=uV, dw %ZERNFUN Zernike functions of order N and frequency M on the unit circle. "UYlC0 S\ % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N TTagZI$ % and angular frequency M, evaluated at positions (R,THETA) on the &v)/mc7D % unit circle. N is a vector of positive integers (including 0), and .+)
AeGh % M is a vector with the same number of elements as N. Each element q x5jaa3 % k of M must be a positive integer, with possible values M(k) = -N(k) gT_tR_g % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, */'j[uj
% and THETA is a vector of angles. R and THETA must have the same N(J'h$E % length. The output Z is a matrix with one column for every (N,M) W:VX^8</ % pair, and one row for every (R,THETA) pair. !&adO,jN+= % Nr"gj$v % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike {F=`IE3)w % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), VX:Kq<XwQ % with delta(m,0) the Kronecker delta, is chosen so that the integral sa?s[ % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, @rP#ktz] % and theta=0 to theta=2*pi) is unity. For the non-normalized j4wsDtmAU % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. k
1lK`p % qm/#kPlM % The Zernike functions are an orthogonal basis on the unit circle. Nt,:`o | % They are used in disciplines such as astronomy, optics, and PO nF_FC % optometry to describe functions on a circular domain. .4J7 ^l % ^U9b)KA % The following table lists the first 15 Zernike functions. ;$vVYC % 3!op'X! % n m Zernike function Normalization %RX!Pi}5+g % -------------------------------------------------- OUhlQq\ % 0 0 1 1 GY rUB59 % 1 1 r * cos(theta) 2 Qk2*=BVh % 1 -1 r * sin(theta) 2 d(YAH@ % 2 -2 r^2 * cos(2*theta) sqrt(6) p`Ok(C_ % 2 0 (2*r^2 - 1) sqrt(3) ;TKsAU % 2 2 r^2 * sin(2*theta) sqrt(6) GdM|?u&s" % 3 -3 r^3 * cos(3*theta) sqrt(8) Gs/G_E(T % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) 5mX"0a_Q % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) |RH^|2:x9Q % 3 3 r^3 * sin(3*theta) sqrt(8) q{}U5(,{0 % 4 -4 r^4 * cos(4*theta) sqrt(10) W0S\g# % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) Ip0`R+8 % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) O[8wF86R % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) =d$m@rc0r % 4 4 r^4 * sin(4*theta) sqrt(10) z
s\N)LyM % -------------------------------------------------- 8&:dzS % !jR 1!i % Example 1: <9[>+X % 62o nMY % % Display the Zernike function Z(n=5,m=1) GPrq( % x = -1:0.01:1; =%S*h)}@ % [X,Y] = meshgrid(x,x); PKZMuEEy, % [theta,r] = cart2pol(X,Y); 8CUl |I ~ % idx = r<=1; fskc'%x % z = nan(size(X)); 1QbD]"=n % z(idx) = zernfun(5,1,r(idx),theta(idx)); 2]5ux!Lqln % figure 3
jghV?I{T % pcolor(x,x,z), shading interp LYuMR,7E % axis square, colorbar CN6b982& % title('Zernike function Z_5^1(r,\theta)') &r!jjT % ?s]?2>p % Example 2: nFjaV`6`@ % :m0pm@ % % Display the first 10 Zernike functions brdY97s4 % x = -1:0.01:1; ${tBu#$-d % [X,Y] = meshgrid(x,x); {tuGkRY2~ % [theta,r] = cart2pol(X,Y); 7-}/{o*,5 % idx = r<=1; ,Qt2 ? % z = nan(size(X)); }0Fu % n = [0 1 1 2 2 2 3 3 3 3]; X
CHN'l' % m = [0 -1 1 -2 0 2 -3 -1 1 3]; nc?Oj
B % Nplot = [4 10 12 16 18 20 22 24 26 28]; #Wt1Ph_; % y = zernfun(n,m,r(idx),theta(idx)); k^%F4d3z@C % figure('Units','normalized') H284
]i % for k = 1:10 qdZo
cTf' % z(idx) = y(:,k); Sr-!-eC % subplot(4,7,Nplot(k)) |iVw7M: % pcolor(x,x,z), shading interp V0*9Tnc % set(gca,'XTick',[],'YTick',[]) `8D'r|=`Eh % axis square H6Kt^s<6xu % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) .c@,$z2M % end :&m0eZZ% % npcL<$<6X % See also ZERNPOL, ZERNFUN2. O*1la/~m 9 j1
tcT WE&"W$0 % Paul Fricker 11/13/2006 y<)q;fI7 ]U.YbWe^ +?Y(6$o b@[\+P] " '.zr:l % Check and prepare the inputs: Gx-tPW} % ----------------------------- ;CA7\&L> if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) I z)~h>-F error('zernfun:NMvectors','N and M must be vectors.') ys9MV%* end SA.,Q~_T7 ANd#m9(x HNV"'p; if length(n)~=length(m) k5)e7Lb( error('zernfun:NMlength','N and M must be the same length.') C6c]M@6 end
MU~nvs;: y_Nn%(j 0^3@>>^ n = n(:); ?N@p~
*x m = m(:); 6n'XRfQp)& if any(mod(n-m,2)) fg8U*7 error('zernfun:NMmultiplesof2', ... ~[
x} 'All N and M must differ by multiples of 2 (including 0).') xkkW?[& end \Zo
xJ& i)+2?<] O\zGN/! if any(m>n) ,7izrf8 error('zernfun:MlessthanN', ... {1]Of'x' 'Each M must be less than or equal to its corresponding N.') 6Er%td)f end VK?c='zg 2bt2h.a qGKQrb,K if any( r>1 | r<0 ) uM9RlI5 error('zernfun:Rlessthan1','All R must be between 0 and 1.') xZ(VvINL' end Fd@:*ER 1|%C66f^ ]0)=0pc]E if ( ~any(size(r)==1) ) || ( ~any(size(theta)==1) ) ,a?$F1Z- error('zernfun:RTHvector','R and THETA must be vectors.') R(F+Xgje end ""^.fh 9oJ=:E~CP *dm?,~f%< r = r(:); "6fTZ< theta = theta(:); '}T6e1#JV length_r = length(r); ;&G8e*bM2 if length_r~=length(theta) zq&,KZ error('zernfun:RTHlength', ... 6z80Y*|eJ 'The number of R- and THETA-values must be equal.') p*Hbc|?{Q& end ZCS{D 5x; y{qT x?MSHOia`P % Check normalization: ckPI^0A! % -------------------- _<1uO=km6 if nargin==5 && ischar(nflag) {9C+=v? isnorm = strcmpi(nflag,'norm'); ['rqz1DL5 if ~isnorm =e$6o 2!'} error('zernfun:normalization','Unrecognized normalization flag.') fd Rw:K8 end F,-S&d else ghd*EXrF
H isnorm = false; &r
Lg/UEV- end |KxFiH B!cg)Y?.bd uM<6][^` %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% -O-qEQd % Compute the Zernike Polynomials O[[#\BL %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% yPqZ , 0cm+: p x1{=~V/ % Determine the required powers of r: ;/8oP ;X2 % ----------------------------------- r&t)%R@q m_abs = abs(m); <H)I06]; rpowers = []; #}rv) for j = 1:length(n) j7)Xm,wI8 rpowers = [rpowers m_abs(j):2:n(j)]; |Skk1# end a}+7MEUmZ/ rpowers = unique(rpowers); UldG0+1d &[hq !v PDnwaK % Pre-compute the values of r raised to the required powers, }#/,nJm' % and compile them in a matrix: 1MCHwX3/ % ----------------------------- P]@m0f if rpowers(1)==0 'e4 ;,m rpowern = arrayfun(@(p)r.^p,rpowers(2:end),'UniformOutput',false); \e/'d~F rpowern = cat(2,rpowern{:}); \=yx~c_$L rpowern = [ones(length_r,1) rpowern]; %:eepG| else 5Q.bwl : rpowern = arrayfun(@(p)r.^p,rpowers,'UniformOutput',false); 4#z@B1Jx rpowern = cat(2,rpowern{:}); :>.~"uWo{ end Et=N`k_gO qxsK-8KT< F-k3F80= % Compute the values of the polynomials: .1.Bf26}d % -------------------------------------- _tg&_P+kV y = zeros(length_r,length(n)); ?[\(i)] for j = 1:length(n) -VESe}c:nQ s = 0:(n(j)-m_abs(j))/2; }7Si2S pows = n(j):-2:m_abs(j); Cr,UP8MO for k = length(s):-1:1 ' [fo p = (1-2*mod(s(k),2))* ... | 1Fy prod(2:(n(j)-s(k)))/ ... dE+xU(\,w prod(2:s(k))/ ... byYdX'd. prod(2:((n(j)-m_abs(j))/2-s(k)))/ ... tVZjtGz= prod(2:((n(j)+m_abs(j))/2-s(k))); @L8('8~d idx = (pows(k)==rpowers); 9tVA.:FOZ y(:,j) = y(:,j) + p*rpowern(:,idx); N4%q-fi end 4425,AR g(\FG if isnorm Nkt(1?:-' y(:,j) = y(:,j)*sqrt((1+(m(j)~=0))*(n(j)+1)/pi); Ch`XwLY9 end d*Y&V$?zl end 'Pudy\Ab % END: Compute the Zernike Polynomials Nw}y_Qf{ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% dlC)&Ai ;$G.?r )k0P' zGb % Compute the Zernike functions: ;f7(d\=y
% ------------------------------ H'E>QT idx_pos = m>0; >_1*/o
JO idx_neg = m<0; <h2WM (n 0+0+%#? bIP{DxKS z = y; #]i*u1 if any(idx_pos) :luVsQ z(:,idx_pos) = y(:,idx_pos).*sin(theta*m(idx_pos)'); #N%xr'H end $
+h~VC if any(idx_neg) k~u$&a z(:,idx_neg) = y(:,idx_neg).*cos(theta*m(idx_neg)'); #J]u3*Tn| end lkK+Fm BF2,E<^A KvC`6 % EOF zernfun udDhJ?
|
|