| 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, JStEOQF4 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, mxu !$wx 这个,跟我们用zygo干涉仪直接拟合出的36项zernike系数,有何关系呢? j,SZJ{ebXg 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? E$&bl AX'-}5T= 3.g 4X?=zd @,}tY ?>a I~Qi):&x function z = zernfun(n,m,r,theta,nflag)
w~jm0jK] %ZERNFUN Zernike functions of order N and frequency M on the unit circle. Crl:v8 % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N {t.S_|IE % and angular frequency M, evaluated at positions (R,THETA) on the ori[[~OyB % unit circle. N is a vector of positive integers (including 0), and _
b</
::Tp % M is a vector with the same number of elements as N. Each element P}>>$$b\Yi % k of M must be a positive integer, with possible values M(k) = -N(k) sTep2W.9 % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, 'H4?V % and THETA is a vector of angles. R and THETA must have the same +EqL| % length. The output Z is a matrix with one column for every (N,M) gjFQDrz( % pair, and one row for every (R,THETA) pair. R3LIN-g( % 1_]%, % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike )O$S3ojZ % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), GXNkl?# % with delta(m,0) the Kronecker delta, is chosen so that the integral y+V>,W)r7 % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, Y7 K2@257 % and theta=0 to theta=2*pi) is unity. For the non-normalized `s3:Vsv4 % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. YfMs~}h, % U!K#g_} % The Zernike functions are an orthogonal basis on the unit circle. z]LVq k % They are used in disciplines such as astronomy, optics, and g!r)yzK % optometry to describe functions on a circular domain. DRTT3;,N % VVpJ + % The following table lists the first 15 Zernike functions. OECVExb@eH % =vriraV" % n m Zernike function Normalization \:'6_K % -------------------------------------------------- -V[!qI % 0 0 1 1 .I $+
E % 1 1 r * cos(theta) 2 1CM8P3 % 1 -1 r * sin(theta) 2 hd[t&?{= % 2 -2 r^2 * cos(2*theta) sqrt(6) wlslG^^(! % 2 0 (2*r^2 - 1) sqrt(3) Dkh=(+> < % 2 2 r^2 * sin(2*theta) sqrt(6) w>}n1Nc$G % 3 -3 r^3 * cos(3*theta) sqrt(8) ~r'ApeI9 % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) qPJSVo % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) ;B(16&l=q % 3 3 r^3 * sin(3*theta) sqrt(8) 86dz Jh % 4 -4 r^4 * cos(4*theta) sqrt(10) v6E5#pse8 % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) zy8+~\a+Y& % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) =NnG[#n% % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) ,_D@ggL- % 4 4 r^4 * sin(4*theta) sqrt(10) /F''4%S?E % -------------------------------------------------- hx/A215L % (?lT @RY/ % Example 1: r>PKl'IbE % Cy B4apJ % % Display the Zernike function Z(n=5,m=1) 5B8fz;l= B % x = -1:0.01:1; 8]O#L}" % [X,Y] = meshgrid(x,x); #e[r0f?U % [theta,r] = cart2pol(X,Y); 7s2*VKr % idx = r<=1; _F^NX% % z = nan(size(X)); a5d_= :S; % z(idx) = zernfun(5,1,r(idx),theta(idx)); :<0lC j % figure cS@p`A7Tpo % pcolor(x,x,z), shading interp Bs>S2] % axis square, colorbar ~DB:/VSmu % title('Zernike function Z_5^1(r,\theta)') ]@}hyM[D; % h uR ^l % Example 2: se}$/Y}t % X &G]ci % % Display the first 10 Zernike functions XaoVv2=G~ % x = -1:0.01:1; D5].^*AbZ % [X,Y] = meshgrid(x,x); ymnK `/J!Q % [theta,r] = cart2pol(X,Y); A 2\3.3 % idx = r<=1; Y`6<:8[? % z = nan(size(X)); A_2lG!!
6 % n = [0 1 1 2 2 2 3 3 3 3]; g0s4ZI+T % m = [0 -1 1 -2 0 2 -3 -1 1 3]; hgwS_L % Nplot = [4 10 12 16 18 20 22 24 26 28]; ?[WUix; % y = zernfun(n,m,r(idx),theta(idx)); Nd@/U
c % figure('Units','normalized') vkM_a}%< % for k = 1:10 6{g&9~V % z(idx) = y(:,k); wsc=6/#u % subplot(4,7,Nplot(k)) U^DR'X= % pcolor(x,x,z), shading interp i1]}Q$ % set(gca,'XTick',[],'YTick',[]) Z[,,(M % axis square AXnKhYlu % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) - ku8n%u % end *TCV}=V G % hQNUA|Q=% % See also ZERNPOL, ZERNFUN2. o>m*e7l, ) :Px`] 5 f3h]t0M % Paul Fricker 11/13/2006 Y;dqrA>@ _6YfPk+ y`/:E<fVk {W%XSE ^?A>)?Sq % Check and prepare the inputs: [p(0g;bx % ----------------------------- W* n|T{n if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) UF}Ji#fqn error('zernfun:NMvectors','N and M must be vectors.') <Skf
n`). end &0d5".|s &b-&0rTqz tZ*>S]qD if length(n)~=length(m) (#qQ;ch error('zernfun:NMlength','N and M must be the same length.') vo~Qo;m end $`lGPi(Jc wARd^Iw d*@K5?O. n = n(:); %.fwNS m = m(:); TIF =fQ if any(mod(n-m,2)) Q]dKyMSSA error('zernfun:NMmultiplesof2', ... y"K[#&,0 'All N and M must differ by multiples of 2 (including 0).') hxw6^EA end J$`5KbT3 o+- 0`!yj 8\PI1U if any(m>n) tCu.Fc@ error('zernfun:MlessthanN', ... bcAk$tA2 'Each M must be less than or equal to its corresponding N.') -f?,%6(1 end ItZ*$I1< 9w1`_r[J U_UN& /f if any( r>1 | r<0 ) qmNG|U& error('zernfun:Rlessthan1','All R must be between 0 and 1.') R#rfnP >
end !?K#f?x<? Tv|iCYB? I-Am9\ if ( ~any(size(r)==1) ) || ( ~any(size(theta)==1) ) e Dpt1 error('zernfun:RTHvector','R and THETA must be vectors.') {rygIl{V end gTdr 3wPUP+)c7 2cZgG^ r = r(:); i7&ay\+@ theta = theta(:); [LV>z length_r = length(r); "DX2Mu= if length_r~=length(theta) iRV=I, error('zernfun:RTHlength', ... w5t|C> 'The number of R- and THETA-values must be equal.') jm'^>p,9G end {GGP8 tK6=F63e AMK(-= % Check normalization: vVjk9_Ul % -------------------- I:;umyRH if nargin==5 && ischar(nflag) |>wGl isnorm = strcmpi(nflag,'norm'); 5d-rF:# if ~isnorm XXXQA Y-,C error('zernfun:normalization','Unrecognized normalization flag.') B!4~A{ end g]d0B!Ar~ else !';;q isnorm = false; ,=: -&~? end H6lZ<R{= LYyud e^N}(Kpy %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% y<l(F?_ % Compute the Zernike Polynomials m@",Zr`f= %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% U[Lr+nKo\ k/)h @K8@ 8KsPAK_ % Determine the required powers of r: a/[)A _- % ----------------------------------- $M$-c{>s m_abs = abs(m); fGWXUJ rpowers = []; =}Yz[-I for j = 1:length(n) q RRvZhf rpowers = [rpowers m_abs(j):2:n(j)]; :*YnH& end W<$!H
V$ rpowers = unique(rpowers); fT
YlIT9 bKEiS8x jVqpokWH % Pre-compute the values of r raised to the required powers, F(Je$c/J|~ % and compile them in a matrix: B#3Q4c$ % ----------------------------- UtRwZ(09 if rpowers(1)==0 eYevj[c; rpowern = arrayfun(@(p)r.^p,rpowers(2:end),'UniformOutput',false); bL5u;iy) rpowern = cat(2,rpowern{:}); 3u<
ntx >< rpowern = [ones(length_r,1) rpowern]; SF da?> else >Sb3]$$ rpowern = arrayfun(@(p)r.^p,rpowers,'UniformOutput',false); pm[+xM9PB rpowern = cat(2,rpowern{:}); h05<1>?| end x0lAJaG PZI6{KOis
?P/73p % Compute the values of the polynomials: 5kojh _\ % -------------------------------------- 8Y:x+v5 y = zeros(length_r,length(n)); )jh~jU? c@ for j = 1:length(n) 3PlIn0+LX s = 0:(n(j)-m_abs(j))/2; lNTbd"}$: pows = n(j):-2:m_abs(j); *;U<b for k = length(s):-1:1 i1*0'x p = (1-2*mod(s(k),2))* ... rbl^ aik prod(2:(n(j)-s(k)))/ ... x~K79Mya prod(2:s(k))/ ... AJ)&+H prod(2:((n(j)-m_abs(j))/2-s(k)))/ ... <,X=M6$0n prod(2:((n(j)+m_abs(j))/2-s(k))); 7y_<BCx
h idx = (pows(k)==rpowers); D0>Pc9 y(:,j) = y(:,j) + p*rpowern(:,idx); }'K-1: end GInw7 5Vai0Qfcu: if isnorm _(I)C`8m y(:,j) = y(:,j)*sqrt((1+(m(j)~=0))*(n(j)+1)/pi); vin3
i&k end
unKgOvtj end e0j4t-lL % END: Compute the Zernike Polynomials dnh~An 9 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 0
ZSn r+ =ADOf_n} YOUB%N9+ % Compute the Zernike functions: G,<l}(tEG % ------------------------------ lQy-&d|=#^ idx_pos = m>0; wuM'M<J@ idx_neg = m<0; {|B[[W\TN l]gW_wUQd Ey=}bBx z = y; |sEuhP\A3 if any(idx_pos) y|zIuI-p z(:,idx_pos) = y(:,idx_pos).*sin(theta*m(idx_pos)'); LF#[$
so{i end d8U<V<H< if any(idx_neg) 5"X@<;H% z(:,idx_neg) = y(:,idx_neg).*cos(theta*m(idx_neg)'); ;>S|?M4GZ end >(.Y%$9"E G6+6uWvl s+z 5"3'n % EOF zernfun {s@ 0<!
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