| 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, O1~7#nJ*4[ 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, Q~(Qh_Ff 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? `xx.,;S 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? `^Ll@Cx" [;{xiW4V] 8SU0q9X. VWzQXo {XIpHr function z = zernfun(n,m,r,theta,nflag) &Y^4>y% %ZERNFUN Zernike functions of order N and frequency M on the unit circle. Ye]K 74M. % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N |Ogh-<|< % and angular frequency M, evaluated at positions (R,THETA) on the ?#GTD?3d % unit circle. N is a vector of positive integers (including 0), and Pm6U:RL % M is a vector with the same number of elements as N. Each element :xHKbWz6j % k of M must be a positive integer, with possible values M(k) = -N(k) gbYM1guiD % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, 8?8V; % and THETA is a vector of angles. R and THETA must have the same tf6-DmMH % length. The output Z is a matrix with one column for every (N,M) \)5mO 8w % pair, and one row for every (R,THETA) pair. sSfP.R % _`p-^I % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike LpY{<:y % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), 8Tg1 >q< % with delta(m,0) the Kronecker delta, is chosen so that the integral / fUdb=!Z % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, U\Y0v.11 % and theta=0 to theta=2*pi) is unity. For the non-normalized }J6:D]Q % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. e|:\Ps `8 % q]yw",muT % The Zernike functions are an orthogonal basis on the unit circle. &[{sA; % They are used in disciplines such as astronomy, optics, and E} ]=<8V % optometry to describe functions on a circular domain. S rH::-{ % 7k,BE2]" % The following table lists the first 15 Zernike functions. w0;4O)H$O % Io*H}$Gf % n m Zernike function Normalization *lA+-gkK* % -------------------------------------------------- E`.hM}h % 0 0 1 1 r+m.!+ % 1 1 r * cos(theta) 2 OvQzMXU^I % 1 -1 r * sin(theta) 2 Uhr2"Nuuy % 2 -2 r^2 * cos(2*theta) sqrt(6) [K,P)V>K % 2 0 (2*r^2 - 1) sqrt(3) S'^ q % 2 2 r^2 * sin(2*theta) sqrt(6) kJl^,q % 3 -3 r^3 * cos(3*theta) sqrt(8) ML'y`S % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) @:RoY vk$ % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) qE2VUEv5Y % 3 3 r^3 * sin(3*theta) sqrt(8) \"$P :Uv % 4 -4 r^4 * cos(4*theta) sqrt(10) ?;v\wx % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) IagM#}m@ % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) @.$-
^- % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) OU.}H $x" % 4 4 r^4 * sin(4*theta) sqrt(10) #8M?y*<I % -------------------------------------------------- CR23$<FC % c*7|>7C$i % Example 1: ;G} % O>+=cg % % Display the Zernike function Z(n=5,m=1) ,ja!OZ0$ % x = -1:0.01:1; B<L7`xL % [X,Y] = meshgrid(x,x); k
L6s49 % [theta,r] = cart2pol(X,Y); "~r)_Ko % idx = r<=1; 'WhJ}Uo\ % z = nan(size(X)); %w[Z/ % z(idx) = zernfun(5,1,r(idx),theta(idx)); aL[6}U0 (} % figure ?Xvy0/s5 % pcolor(x,x,z), shading interp &*"*b\ % axis square, colorbar wdP(MkaV % title('Zernike function Z_5^1(r,\theta)') Z@dVK`nD % s!?uLSEdb % Example 2: ^?H|RAp % Dfzj/spFV % % Display the first 10 Zernike functions U!-Nx9 % x = -1:0.01:1; +@^);b6 % [X,Y] = meshgrid(x,x); v[|W\y@H/3 % [theta,r] = cart2pol(X,Y); ^wWbW&<Tg % idx = r<=1; vTx>z\7q, % z = nan(size(X)); l+ >eb % n = [0 1 1 2 2 2 3 3 3 3]; XfE9QA[ % m = [0 -1 1 -2 0 2 -3 -1 1 3]; hT 1JEu % Nplot = [4 10 12 16 18 20 22 24 26 28]; P~{8L.w!>W % y = zernfun(n,m,r(idx),theta(idx)); gZ^Qt.6Z % figure('Units','normalized') DqQp47kp % for k = 1:10 S=-$:65 % z(idx) = y(:,k); 9o5D3
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K % subplot(4,7,Nplot(k)) CR'%=N04^ % pcolor(x,x,z), shading interp w -o#=R_ % set(gca,'XTick',[],'YTick',[]) f%.Ngf9 % axis square xrvM}Il % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) ?110} [jw % end I4jRz*Ufe? % s*la`(x % See also ZERNPOL, ZERNFUN2. 0c`zg7| J6s]vV q" R]X 0D. % Paul Fricker 11/13/2006 AcuF0KWw/ f/O6~I&g lh'S_p8g nI]EfHU HQ-++;Q % Check and prepare the inputs: =w+8q1!o % ----------------------------- ? nW>'z if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) JXJ+lZmsz error('zernfun:NMvectors','N and M must be vectors.') :CE4<
{V end a)ry}E =f z4SJxL '+_>PBOc if length(n)~=length(m) x']'ODs error('zernfun:NMlength','N and M must be the same length.') `5@F'tKQ end 5_'lu { V6pC To>,8E+GAb n = n(:); `Fn"QL- m = m(:); }?9&xVh?\ if any(mod(n-m,2)) DO80HS3ZD error('zernfun:NMmultiplesof2', ... zw+aZDcV( 'All N and M must differ by multiples of 2 (including 0).') l{Df{1b. end b&F9<XLqq _aPAn|. WChP,hw if any(m>n) swF{}S" error('zernfun:MlessthanN', ... 0h@FHw2d 'Each M must be less than or equal to its corresponding N.') nU_O|l9 end Io.RT+slB AChz}N$C ;_(f(8BO
if any( r>1 | r<0 ) iwJ_~ error('zernfun:Rlessthan1','All R must be between 0 and 1.') d>hv-nD end geR+v+B, .}!.4J%q2 Gc|)4c if ( ~any(size(r)==1) ) || ( ~any(size(theta)==1) ) *z0d~j*W; error('zernfun:RTHvector','R and THETA must be vectors.') ~+dps i end YGyv)\ {Uw
0zC Ax=HDW} r = r(:); hN'])[+V theta = theta(:); pIlEoG=[_ length_r = length(r); (P)G|2= if length_r~=length(theta) LQR2T5S/Q, error('zernfun:RTHlength', ... i
6G40!G=) 'The number of R- and THETA-values must be equal.') Tzex\]fw end B`}um;T#~, f,HUr% @ 2 kDsIEA % Check normalization: J3 _aHI % -------------------- r9@=d if nargin==5 && ischar(nflag) 6CBk=)qH isnorm = strcmpi(nflag,'norm'); gN=.}$Kfu if ~isnorm -G,}f\Cg error('zernfun:normalization','Unrecognized normalization flag.') WBE>0L end
T^}UE< else @z@%vr=vX isnorm = false; KG'i#(u[ end ! K>iSF< =j,WQ66r3 )Z/"P\qo %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% &P?2H66s % Compute the Zernike Polynomials iQ/~?'PB %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% F_
F"3'[ Tz]R}DKB& 2zTi/&K& % Determine the required powers of r: ,S-h~x % ----------------------------------- @RoZd? m_abs = abs(m); KrE'M rpowers = []; <gp?}Lk for j = 1:length(n) TLdlPBnr8 rpowers = [rpowers m_abs(j):2:n(j)]; 3"y 6|e/5 end xl\Kj2^ rpowers = unique(rpowers); /v R>.' 75^6?#GS ":Dm/g % Pre-compute the values of r raised to the required powers, &3Zq1o % and compile them in a matrix: Zzlf1#26\ % ----------------------------- >d/H4;8 if rpowers(1)==0 =hPXLCeC rpowern = arrayfun(@(p)r.^p,rpowers(2:end),'UniformOutput',false); "%-Vrb=:Y rpowern = cat(2,rpowern{:}); o<`hj&s rpowern = [ones(length_r,1) rpowern]; "D(Lp*3hj& else g$nS6w|5H rpowern = arrayfun(@(p)r.^p,rpowers,'UniformOutput',false); kWzN {]v rpowern = cat(2,rpowern{:}); 8%[pno
|0I end @]@|H?
,EB}IG] j_Szw
w- % Compute the values of the polynomials: %**f`L%jN % -------------------------------------- HK@ij,px y = zeros(length_r,length(n)); cl4E6\?z for j = 1:length(n) L|=5jn9 : s = 0:(n(j)-m_abs(j))/2; f`9Mcli! pows = n(j):-2:m_abs(j); wcGK*sWG- for k = length(s):-1:1 jj5S+ >4 p = (1-2*mod(s(k),2))* ... !J`lA prod(2:(n(j)-s(k)))/ ... )[Y B& prod(2:s(k))/ ... :L[>!~YG_n prod(2:((n(j)-m_abs(j))/2-s(k)))/ ... {K,In)4 prod(2:((n(j)+m_abs(j))/2-s(k))); 4DA34m( idx = (pows(k)==rpowers); )kD/ 8 y(:,j) = y(:,j) + p*rpowern(:,idx); Wlj&_~ end t'qYM5 ,lyW'<~gA if isnorm }#XFa# y(:,j) = y(:,j)*sqrt((1+(m(j)~=0))*(n(j)+1)/pi); Jup)m/ end uDF;_bli)H end FcDS*ZEk! % END: Compute the Zernike Polynomials \(o"/* %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% G=zWhqieh Z~5) )5Ye; tdy2ZPVtTV % Compute the Zernike functions: zsFzg.$3& % ------------------------------ 0I&k_7_ idx_pos = m>0; Gz[yD
~6a idx_neg = m<0; F@w; .e! "W|A^@r} }Mcb\+[ z = y; "LMj,qZ1! if any(idx_pos) x]~TGzS z(:,idx_pos) = y(:,idx_pos).*sin(theta*m(idx_pos)'); YGp+[|' end )9QtnM if any(idx_neg) yIMqQSt79z z(:,idx_neg) = y(:,idx_neg).*cos(theta*m(idx_neg)'); #/)t]&n end rqdwQ ]MbPivM |c_qq Bd % EOF zernfun {T){!UVp!
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