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, k6(9Rw8bCk 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, naaww 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? -ge :y2R_w 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? 2 y;J 11\ O9/7?"l" Dpf"H .$s>b#m O 3B^`xnV function z = zernfun(n,m,r,theta,nflag) rL9u7)x %ZERNFUN Zernike functions of order N and frequency M on the unit circle. +#wh`9[wBt % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N vi8)U]6 % and angular frequency M, evaluated at positions (R,THETA) on the ]N#%exBVo % unit circle. N is a vector of positive integers (including 0), and 4r+s"
| % M is a vector with the same number of elements as N. Each element ]hC6PKJU % k of M must be a positive integer, with possible values M(k) = -N(k) }iBFo\vU % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, !J/fJW>m6 % and THETA is a vector of angles. R and THETA must have the same sSdnH_;& % length. The output Z is a matrix with one column for every (N,M) %]iE(!>3oy % pair, and one row for every (R,THETA) pair. h!4jl0oX] % g=q1@ ) % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike Z<A BK`rEO % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), yr"BeTrS. % with delta(m,0) the Kronecker delta, is chosen so that the integral P-2 5]- % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, rd\:. % and theta=0 to theta=2*pi) is unity. For the non-normalized aZBS!X % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. d:"#_ % -&UP[Mq % The Zernike functions are an orthogonal basis on the unit circle. !$1'q~sO % They are used in disciplines such as astronomy, optics, and wiE'6CM % optometry to describe functions on a circular domain. jVxX! V % %+F%C=GqI % The following table lists the first 15 Zernike functions. +jifbf- % 'ai3f % n m Zernike function Normalization BJ,D1E % -------------------------------------------------- Z H1UAf % 0 0 1 1 $bdtiD % 1 1 r * cos(theta) 2 k __MYb % 1 -1 r * sin(theta) 2 ("!P_Q# % 2 -2 r^2 * cos(2*theta) sqrt(6) ?mME^?x
Mu % 2 0 (2*r^2 - 1) sqrt(3) {%! >0@7 % 2 2 r^2 * sin(2*theta) sqrt(6) UU;U,q % 3 -3 r^3 * cos(3*theta) sqrt(8) `COnb@uD % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) SAUfA5|e % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) 6{8dv9tK % 3 3 r^3 * sin(3*theta) sqrt(8) )i$:iI
>k % 4 -4 r^4 * cos(4*theta) sqrt(10) mQiVTIP3[O % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) 5+yT{,(5 % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) ^W)h=49PN % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) %'`L+y % 4 4 r^4 * sin(4*theta) sqrt(10) 3~5%6` % -------------------------------------------------- = 3("gScUj % tY>_+)oi % Example 1: LF?MO1!M % <{"Jy)Uf % % Display the Zernike function Z(n=5,m=1) 3l?-H|T % x = -1:0.01:1; 7!kbe2/]' % [X,Y] = meshgrid(x,x); hF4gz*Q % [theta,r] = cart2pol(X,Y); ?K9zTas@ % idx = r<=1; ?]In@h- % z = nan(size(X)); XxeyGs^%9 % z(idx) = zernfun(5,1,r(idx),theta(idx)); 1*vt\,G % figure Y[p % pcolor(x,x,z), shading interp L2P#5B!S % axis square, colorbar y%NZ(Y,v % title('Zernike function Z_5^1(r,\theta)') 0n('F % PYPDK*Ie % Example 2: Fmo^ ?~b % `k.Nphx~% % % Display the first 10 Zernike functions fJ8Q\lb<_ % x = -1:0.01:1; A!n)Fpk
% [X,Y] = meshgrid(x,x); xzrA%1y % [theta,r] = cart2pol(X,Y); .Km6
(U % idx = r<=1; GDBxciv % z = nan(size(X)); `j1(GQt % n = [0 1 1 2 2 2 3 3 3 3]; %*Aq%,.={ % m = [0 -1 1 -2 0 2 -3 -1 1 3]; tLc9- % Nplot = [4 10 12 16 18 20 22 24 26 28]; AC& }8w[>u % y = zernfun(n,m,r(idx),theta(idx)); ,LpG E>s % figure('Units','normalized') ZlEH3-Zv % for k = 1:10 #lo1GoL\ % z(idx) = y(:,k); ,{rm<M.) % subplot(4,7,Nplot(k)) !y 7SCz
g % pcolor(x,x,z), shading interp JrhDqyk* % set(gca,'XTick',[],'YTick',[]) =Ti[Q5SZ % axis square VzZ'W[/7)B % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) R3\oLT4 % end _A5. % /QT"5fxKJ % See also ZERNPOL, ZERNFUN2. 2S#|[wq( )xPfz N sNk
% Paul Fricker 11/13/2006 6B .x= hErO.ad1o <~ 9a3c? *~H\#N|x WY3D.z-</ % Check and prepare the inputs: fAHf}j % ----------------------------- I%qZMoS1h if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) co-dq\P error('zernfun:NMvectors','N and M must be vectors.') |y}iOI end $Lx2!Zy +;*dFL WD${f#]N if length(n)~=length(m) y)%CNH)*x error('zernfun:NMlength','N and M must be the same length.') jXCSD@?]K end pjVF^gv,* f:_mr zz CQGq}.Jt! n = n(:); Jg:%|g m = m(:); `eXTVi|0"~ if any(mod(n-m,2)) {6, l#z error('zernfun:NMmultiplesof2', ... dnXre*rhz 'All N and M must differ by multiples of 2 (including 0).') "z/)> ?Wn end /CW
0N@
7%g8&d 0%f}w0]: if any(m>n) sH_5.+,` error('zernfun:MlessthanN', ... $wq[W,'#L 'Each M must be less than or equal to its corresponding N.') 08 $y1; end Sh(W s2b7 Q^c)T>OAI -o`Eka!ELz if any( r>1 | r<0 ) +^0Q~>=VD error('zernfun:Rlessthan1','All R must be between 0 and 1.') TcjTF|q> end 7%x
3o#& 2qQG sCi"qtHP if ( ~any(size(r)==1) ) || ( ~any(size(theta)==1) ) npD`9ff error('zernfun:RTHvector','R and THETA must be vectors.') BXx0Z
%e.3 end R<-u`uXnP q5D_bm7,3 AXmW7/Sj" r = r(:); w4UaWT1J theta = theta(:); L
UitY length_r = length(r); ZA>p~Zt if length_r~=length(theta) 1B#Z<p error('zernfun:RTHlength', ... d@u)'AY%/ 'The number of R- and THETA-values must be equal.') uOU?-WtPz end *RpBKm&^7 HXY,e$c#y V <;vy&& % Check normalization: ZBX,4kxK7 % -------------------- bU+
z(Eg6 if nargin==5 && ischar(nflag) D;RZE isnorm = strcmpi(nflag,'norm'); :p6.v>s8 if ~isnorm y;1
'hP& error('zernfun:normalization','Unrecognized normalization flag.') f:)%+)U<Xm end wy)I6`v else tOQura isnorm = false; h%0hryGB end 4IEF{"c_8 &Fxw19[G gOnVN6 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% :kMEL* % Compute the Zernike Polynomials 6gSo>F4= %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% _t+.I9kQ J#L"kz luYa+E0 % Determine the required powers of r: `fA|])3T % ----------------------------------- Pn;Tg7oz m_abs = abs(m); @mbR I0 rpowers = []; 9~FB^3Nz_ for j = 1:length(n) hrt]Qn& rpowers = [rpowers m_abs(j):2:n(j)]; 5qx,b&^w end FSp57W$ rpowers = unique(rpowers); fQtV-\Bc r'C(+E ( <+%#xi/_ % Pre-compute the values of r raised to the required powers, %%=PpKYtSD % and compile them in a matrix: k'hJ@6eKS % ----------------------------- Uz&XqjS if rpowers(1)==0 yhBf %m rpowern = arrayfun(@(p)r.^p,rpowers(2:end),'UniformOutput',false); 9)Jc'd| rpowern = cat(2,rpowern{:}); JkiMrpkuk rpowern = [ones(length_r,1) rpowern]; zURob MpE# else SW^/\cJ^ rpowern = arrayfun(@(p)r.^p,rpowers,'UniformOutput',false); 1E]|>)$ rpowern = cat(2,rpowern{:}); w
N-np3k end 5V{ B,T %#^)hX,+Q tCw.wDq3= % Compute the values of the polynomials: 0VOj,)K= % -------------------------------------- _Coh11 y = zeros(length_r,length(n)); HalkNR-eEm for j = 1:length(n) ?3v Oc/2@ s = 0:(n(j)-m_abs(j))/2; aeP
6JHj pows = n(j):-2:m_abs(j); rps2sXGr for k = length(s):-1:1 0d%p<c p = (1-2*mod(s(k),2))* ... +Je(]b@ prod(2:(n(j)-s(k)))/ ... cc"L> XoK prod(2:s(k))/ ... pu"`*NL prod(2:((n(j)-m_abs(j))/2-s(k)))/ ... AhjUFz prod(2:((n(j)+m_abs(j))/2-s(k))); U!0 Qf7D idx = (pows(k)==rpowers); 5tIM@,.I/ y(:,j) = y(:,j) + p*rpowern(:,idx); wGXnS"L! end K1F,M9 0] .7!n%Ks if isnorm le*1L8n$' y(:,j) = y(:,j)*sqrt((1+(m(j)~=0))*(n(j)+1)/pi); :-I~-Yj end ,s?7EHtC end -]uN16\ F % END: Compute the Zernike Polynomials 2rr}5i)r| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% /Ww_fY jf_0IE nmLn]U= % Compute the Zernike functions: s?.A
$^t % ------------------------------ *=- o0 c idx_pos = m>0; ~"Pu6-\VT idx_neg = m<0; x}w"2[fL 4|& | |