| 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, J"z8olV 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, a([cuh. 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? N#UyAm<9 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? hxv/285B ul:jn]S* ;Z8K3p r..Rh9v/=E -Z#A}h function z = zernfun(n,m,r,theta,nflag) 3cs'Oz<w %ZERNFUN Zernike functions of order N and frequency M on the unit circle. , n+dB2\ % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N sqkPC_;A % and angular frequency M, evaluated at positions (R,THETA) on the OW6i2 >Or % unit circle. N is a vector of positive integers (including 0), and {?t=*l\S{w % M is a vector with the same number of elements as N. Each element 5` Q#2 % k of M must be a positive integer, with possible values M(k) = -N(k) t<Og?m}( % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, Q!@"Y/ % and THETA is a vector of angles. R and THETA must have the same Iz ,C!c % length. The output Z is a matrix with one column for every (N,M) qEywExdiu % pair, and one row for every (R,THETA) pair. Wx^L~[l % -ERDW Y % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike tW 9vo-{+ % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), UGAP$_j
]P % with delta(m,0) the Kronecker delta, is chosen so that the integral x=9drKIw> % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, -()CgtSR % and theta=0 to theta=2*pi) is unity. For the non-normalized RCsd % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. a*o=,! % QupCr/Hs % The Zernike functions are an orthogonal basis on the unit circle. 7q(RQQp % They are used in disciplines such as astronomy, optics, and |J8c|h< % optometry to describe functions on a circular domain. &6!x;RB % tNq~M % The following table lists the first 15 Zernike functions. \`x$@s? % rFGbp8(2 % n m Zernike function Normalization teET nz_L % -------------------------------------------------- Es)Kw3^a % 0 0 1 1 @UX'(W % 1 1 r * cos(theta) 2 Yz[^?M%(D % 1 -1 r * sin(theta) 2 yV_aza % 2 -2 r^2 * cos(2*theta) sqrt(6) -cOLgrmp % 2 0 (2*r^2 - 1) sqrt(3) N5o jXX!l% % 2 2 r^2 * sin(2*theta) sqrt(6) f BukrPsV % 3 -3 r^3 * cos(3*theta) sqrt(8) !hEtUF % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) 6=iz@C7r % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) =r#of|`Q % 3 3 r^3 * sin(3*theta) sqrt(8) "*<9)vQ6| % 4 -4 r^4 * cos(4*theta) sqrt(10) 8I`>tY % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) Hh,q)(Wo % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) s)\%%CM % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) \&"gCv# % 4 4 r^4 * sin(4*theta) sqrt(10) 4OC^IS % -------------------------------------------------- `cCsJm$V" % [>v.#:YM^ % Example 1: vDqmD{%4N % O*X]oX % % Display the Zernike function Z(n=5,m=1) AYfW}V" % x = -1:0.01:1; ,d$V-~2, % [X,Y] = meshgrid(x,x); ~CQsv` % [theta,r] = cart2pol(X,Y); + C aPF % idx = r<=1; 7gNJ}pLDx % z = nan(size(X)); VPet1hAy % z(idx) = zernfun(5,1,r(idx),theta(idx)); n~@;[=o?5 % figure t*iKkV^aE % pcolor(x,x,z), shading interp MQ7N8 @!t % axis square, colorbar 9-5H~<}fF % title('Zernike function Z_5^1(r,\theta)') lmfvT}$B % w9G (^jS6 % Example 2: jEo)#j];`< % !g'kWE[ % % Display the first 10 Zernike functions //xK v{3fI % x = -1:0.01:1; VG_ PBG( % [X,Y] = meshgrid(x,x); uD4on} % [theta,r] = cart2pol(X,Y); *2P%731n5 % idx = r<=1; eVGO6 2|! % z = nan(size(X)); )[oegfnn- % n = [0 1 1 2 2 2 3 3 3 3]; \!x~FVA % m = [0 -1 1 -2 0 2 -3 -1 1 3]; $SQUN*/> % Nplot = [4 10 12 16 18 20 22 24 26 28]; 2<q>]G-nN % y = zernfun(n,m,r(idx),theta(idx)); clV3x`z % figure('Units','normalized') H`d595<=i; % for k = 1:10 ^ ~'&K e % z(idx) = y(:,k); ;SnpD)x@) % subplot(4,7,Nplot(k)) oR}cE
Sr % pcolor(x,x,z), shading interp B]iPixA6 % set(gca,'XTick',[],'YTick',[]) 6Cfu19Dx % axis square I&vD >a5# % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) z@Pv~" % end M#Kke9%2 % lJb1{\|., % See also ZERNPOL, ZERNFUN2. |Tv}leJF 'guXdX]Gu uGt}H n % Paul Fricker 11/13/2006 t/%{R.1MN 2@~.FBby7@ 4}.PQ{ /<C}v~r wIQ~a % Check and prepare the inputs: =>3wI'I % ----------------------------- ( f]@lNmx if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) E.LD1Pm0 error('zernfun:NMvectors','N and M must be vectors.') WVZ](D8Gc] end ~?#>QN\\c H?oBax: O2{~Q{p if length(n)~=length(m) L)(JaZyV5 error('zernfun:NMlength','N and M must be the same length.') xbqFek$/r end /{Mo'.=Z 27J!oin$ HKp|I%b]J n = n(:); `) y<X#[8 m = m(:); nwS @r if any(mod(n-m,2)) `)~]3zmG error('zernfun:NMmultiplesof2', ... }Wlm#t 'All N and M must differ by multiples of 2 (including 0).') QQI,$HId end \3"jW1Wb 'Dn\.x^]1 WwUhwY1o!L if any(m>n) 0Wkk$0h9 error('zernfun:MlessthanN', ... FP=up#zl 'Each M must be less than or equal to its corresponding N.') %plu]^Vy end \<ko)I#% )fy-]Ky
* ES}V\k*} if any( r>1 | r<0 ) =e)t,YVm error('zernfun:Rlessthan1','All R must be between 0 and 1.') (n{x"rLy/ end $-=xG&fSz W{RZ@3ZY &L[i"1a if ( ~any(size(r)==1) ) || ( ~any(size(theta)==1) ) dl]pdg< error('zernfun:RTHvector','R and THETA must be vectors.') ^%n]_[RUn4 end *O|_)G 'GI|
t o;TS69|D r = r(:); _lG|t6y theta = theta(:); ~] &yHzp2 length_r = length(r); "hmLe(jo} if length_r~=length(theta) K<rv|bJ error('zernfun:RTHlength', ... 9r.h^ 'The number of R- and THETA-values must be equal.') H@xHkqan end v!`:{)2C yJK:4af;. T09 5]*Hm % Check normalization: %lk^(@+ T % -------------------- ,&~-Sq)~ if nargin==5 && ischar(nflag) mv,5Q6! isnorm = strcmpi(nflag,'norm'); Wsb>3J if ~isnorm =,b6yV+$D error('zernfun:normalization','Unrecognized normalization flag.') 1oc@]0n end AQ&vq$ else "T$LJ1E isnorm = false; EQWRfx?d end 5e3p9K`5 #iKPp0`K* })+iAxR %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% wz.. % Compute the Zernike Polynomials 2qdc$I&$ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% tQ*?L c/7}5#Rs P{LS +. % Determine the required powers of r: /X]gm\x7s % ----------------------------------- .-'_At4g m_abs = abs(m); l 88n*O rpowers = []; #<~oR5ddlb for j = 1:length(n) ;Fo7 -kK rpowers = [rpowers m_abs(j):2:n(j)]; u6 QW*8b4 end We++DWp rpowers = unique(rpowers); !1ZItJ74# H:EK&$sU 6j8\3H~ % Pre-compute the values of r raised to the required powers, 2$o#b. % and compile them in a matrix: `$Um % ----------------------------- /d+v4GIB if rpowers(1)==0 h3bQ<?m rpowern = arrayfun(@(p)r.^p,rpowers(2:end),'UniformOutput',false); 7'OR;b$ rpowern = cat(2,rpowern{:}); 7+88o:G9 rpowern = [ones(length_r,1) rpowern]; ?V}ub>J/= else ]x).C[^ rpowern = arrayfun(@(p)r.^p,rpowers,'UniformOutput',false); yEMM@5W)8 rpowern = cat(2,rpowern{:}); Oq$-*N end >z~_s6#CP \K9.]PfbI GSs?!BIC % Compute the values of the polynomials: ub!lHl % -------------------------------------- );T&pm:C> y = zeros(length_r,length(n)); (t){o>l for j = 1:length(n) WJxcJE s = 0:(n(j)-m_abs(j))/2; _M&n~ r pows = n(j):-2:m_abs(j); 15VvZ![$V for k = length(s):-1:1 mU(v9Jpf7 p = (1-2*mod(s(k),2))* ... z;?ztpa@ prod(2:(n(j)-s(k)))/ ... 2}7 _Y6RS* prod(2:s(k))/ ... $}IG+,L prod(2:((n(j)-m_abs(j))/2-s(k)))/ ... ck%.D%= prod(2:((n(j)+m_abs(j))/2-s(k))); [ #ih
o(/ idx = (pows(k)==rpowers); }Ml BmD y(:,j) = y(:,j) + p*rpowern(:,idx); H
"Io!{aKU end & kVa*O DE7y\oO] if isnorm $tF\7.e@ y(:,j) = y(:,j)*sqrt((1+(m(j)~=0))*(n(j)+1)/pi); }z#M!~ end b)x0;8< end }
xA@3RT % END: Compute the Zernike Polynomials H5#]MOAP %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% &^K(9" YcV^Fqi! .%dGSDru % Compute the Zernike functions: `\|@w@f|; % ------------------------------ JU;`c>8=) idx_pos = m>0; Pwj|]0Y@ idx_neg = m<0; r`"T{o\e FZ}^)u}o *iY:R z = y; [3sZ=)G if any(idx_pos) 3=o4ncg( z(:,idx_pos) = y(:,idx_pos).*sin(theta*m(idx_pos)'); cHVJ7yAZI end mR|5$1[b if any(idx_neg) x_I*6? z(:,idx_neg) = y(:,idx_neg).*cos(theta*m(idx_neg)');
qou\4YZ end */JYP + Qd\='*:! )t3`O$J % EOF zernfun ?{}P#sn
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