| 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, iDD$pd,e\ 我输入10阶的n、m,r,theta为38025*1向量,最后得到的z是29525*10阶的矩阵, #K&Gp- 这个,跟我们用zygo干涉仪直接拟合出的36项zernike系数,有何关系呢? 7$#u 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? 4e +ai<
q>+ ,)io5nZF bMBLXk T4F/w|Q function z = zernfun(n,m,r,theta,nflag) =lSNs %ZERNFUN Zernike functions of order N and frequency M on the unit circle. Xc.`-J~Il % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N {[F A# % and angular frequency M, evaluated at positions (R,THETA) on the sRfcF`7 % unit circle. N is a vector of positive integers (including 0), and <naz+QK' % M is a vector with the same number of elements as N. Each element 8EY:tzw % k of M must be a positive integer, with possible values M(k) = -N(k) ZC8wA;!z^ % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, 5R7DDJk % and THETA is a vector of angles. R and THETA must have the same &Qm@9I s % length. The output Z is a matrix with one column for every (N,M) 8k79&| % pair, and one row for every (R,THETA) pair. Va8&Z % n@w%Zl % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike .C(tMF]D, % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), X?Au/ % with delta(m,0) the Kronecker delta, is chosen so that the integral \NC3'G:Ii % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, N g,j# % and theta=0 to theta=2*pi) is unity. For the non-normalized
5dg(e3T % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. adw2x pj % %)wjR/o % The Zernike functions are an orthogonal basis on the unit circle. I@3MO0V^ % They are used in disciplines such as astronomy, optics, and ;rS{: % optometry to describe functions on a circular domain. Js;h% % pJ{Y
lS{ % The following table lists the first 15 Zernike functions. D,6:EV"sa % Dzbz)Zst % n m Zernike function Normalization uq{beC % -------------------------------------------------- -YE^zzh % 0 0 1 1 DI%saw % 1 1 r * cos(theta) 2 -HuA
\0J % 1 -1 r * sin(theta) 2 Y$zSQ_k;U % 2 -2 r^2 * cos(2*theta) sqrt(6) P* o9a % 2 0 (2*r^2 - 1) sqrt(3) 5X+A"X
;C % 2 2 r^2 * sin(2*theta) sqrt(6) =QsYXK7Mn4 % 3 -3 r^3 * cos(3*theta) sqrt(8) 5)E @F9N % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) [gB+C84%% % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) =#\:}@J5I % 3 3 r^3 * sin(3*theta) sqrt(8) 8-i#8'/x % 4 -4 r^4 * cos(4*theta) sqrt(10)
l^qI,M % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) Y0>y8UV % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) D]}G.v1 % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) rGO8!X 3d % 4 4 r^4 * sin(4*theta) sqrt(10) fIF8%J ^3 % -------------------------------------------------- kP"9&R`E % "}!G!k: % Example 1: 7L??ae % =Uh$&m % % Display the Zernike function Z(n=5,m=1) m2o0y++TjW % x = -1:0.01:1; g){<y~Mk % [X,Y] = meshgrid(x,x); $?Wb}DU7_L % [theta,r] = cart2pol(X,Y); l\mPHA23 % idx = r<=1; nlYNN/@" % z = nan(size(X)); putrSSL} % z(idx) = zernfun(5,1,r(idx),theta(idx)); vbNBLCwug % figure G?ZXWu. % pcolor(x,x,z), shading interp w@b)g % axis square, colorbar q7!{?\T% % title('Zernike function Z_5^1(r,\theta)') Fp:'M X % E3i4=!Y % Example 2: w &(ag$p' % OnK4] S5 % % Display the first 10 Zernike functions <N)oS-m> % x = -1:0.01:1; T|p"0b A % [X,Y] = meshgrid(x,x); liZxBs
:%i % [theta,r] = cart2pol(X,Y); WM{=CD % idx = r<=1; ^_6|X]tz1T % z = nan(size(X)); g*Phv|kI % n = [0 1 1 2 2 2 3 3 3 3]; O}P`P'Y|' % m = [0 -1 1 -2 0 2 -3 -1 1 3]; w@pPcZ>z/ % Nplot = [4 10 12 16 18 20 22 24 26 28]; gSgr6TH0 % y = zernfun(n,m,r(idx),theta(idx)); ;,TFr}p` % figure('Units','normalized') "zc l|@ % for k = 1:10 s S
Mh`4' % z(idx) = y(:,k); 0erNc'e % subplot(4,7,Nplot(k)) nu^436MSOa % pcolor(x,x,z), shading interp 6mE\OS-I % set(gca,'XTick',[],'YTick',[]) |zU-KGO& % axis square pJ=#zsE0 % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) GeqPRah % end @,}UWU % Bwrx *J % See also ZERNPOL, ZERNFUN2. =vPj%oLp'a ~@!bsLSMU %)|s1B'd % Paul Fricker 11/13/2006 yX5\gO6G B[}6-2<>?C N;R^h? ' *I+Q~4 LscGTs, % Check and prepare the inputs: 4
:v=pZ % ----------------------------- fOHxtHM if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) bLL2 error('zernfun:NMvectors','N and M must be vectors.') @d_M@\r=j end B:<VA= u?"Vm YQ}o?Q$z if length(n)~=length(m) _M1 %Z~ error('zernfun:NMlength','N and M must be the same length.') *v`eUQ: end
jo7\`#(Q 0"R|..l/ :]"V-1#} n = n(:); ]iWRo' m = m(:); @ZJS&23E if any(mod(n-m,2)) FwK]$4* error('zernfun:NMmultiplesof2', ... *Ly6`HZ9 'All N and M must differ by multiples of 2 (including 0).') [7-?7mp!B end lYIH/:T l}h!B_P' 2eogY# if any(m>n) e.%nRhSs3 error('zernfun:MlessthanN', ... rOYx
b }1 'Each M must be less than or equal to its corresponding N.') yauvXosX end ]|@^1we 54,er$$V /
1RpM]d if any( r>1 | r<0 ) bD^owa error('zernfun:Rlessthan1','All R must be between 0 and 1.') CITc2v3a end !Cs_F&l"j x^ni1=kU `^vE9nW7 if ( ~any(size(r)==1) ) || ( ~any(size(theta)==1) ) mDWG7 Asp error('zernfun:RTHvector','R and THETA must be vectors.') im8 CmQ end `L
zPotz =I<R! ZSN SM'|+ d r = r(:); 0Gk<l{o?^ theta = theta(:); baasGa3}s length_r = length(r); |)&%A%m if length_r~=length(theta) 4*L_)z&4; error('zernfun:RTHlength', ... D9df=lv
mD 'The number of R- and THETA-values must be equal.') H\
% 7% end J,hCvm ' QG?nu u,
ff>/1 % Check normalization: _$'ashF % -------------------- Z;i:]( if nargin==5 && ischar(nflag) ^~dWU> isnorm = strcmpi(nflag,'norm'); w
xH7?tsf if ~isnorm 5R-6ji error('zernfun:normalization','Unrecognized normalization flag.') RN1_S end
Hz~zu{;{J else :h$$J
lP isnorm = false; eRYK3W end )4OxY[2J 1x)J[fyId +0&/g&a\R %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +TJCLZ.. % Compute the Zernike Polynomials
2iOV/=+ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |=w@H]r uT{q9=w 7r!x1 % Determine the required powers of r: Wri<h:1 % ----------------------------------- )UR7i8]!0 m_abs = abs(m); A<{{iBEI` rpowers = []; WY/}1X9.% for j = 1:length(n) 2:kH[# rpowers = [rpowers m_abs(j):2:n(j)]; %A`+WYeuX end vt8By@]: rpowers = unique(rpowers); l;Wj] X,
n:,' JI}'dU>*U: % Pre-compute the values of r raised to the required powers, }j%5t ~Qa % and compile them in a matrix: Y|n"dMrL % ----------------------------- p'%s=TGwv if rpowers(1)==0 AKC`TA*E rpowern = arrayfun(@(p)r.^p,rpowers(2:end),'UniformOutput',false); yAt^; rpowern = cat(2,rpowern{:}); 3n _htgcv rpowern = [ones(length_r,1) rpowern]; ,prf;|e? else Xhm
c6? rpowern = arrayfun(@(p)r.^p,rpowers,'UniformOutput',false); M >u_4AY rpowern = cat(2,rpowern{:}); az$FnVNn= end CrLrw T r;{.%s7 .]^?<bG % Compute the values of the polynomials: ;+%rw 2Z,B % -------------------------------------- icgfB-1|i y = zeros(length_r,length(n)); O-^Ma-} for j = 1:length(n) se)TzI^]b@ s = 0:(n(j)-m_abs(j))/2; \D4:Nt# pows = n(j):-2:m_abs(j); Hka2 for k = length(s):-1:1 mt
.sucT p = (1-2*mod(s(k),2))* ... s AkdMo prod(2:(n(j)-s(k)))/ ... g#bRT*,L prod(2:s(k))/ ... iTwm3V
P prod(2:((n(j)-m_abs(j))/2-s(k)))/ ... Y4-t7UlS; prod(2:((n(j)+m_abs(j))/2-s(k))); +>,I1{u%& idx = (pows(k)==rpowers); s[jTP(d)8 y(:,j) = y(:,j) + p*rpowern(:,idx); ax`o>_) end R_C) zPO9!?7| if isnorm HN"Z]/5j y(:,j) = y(:,j)*sqrt((1+(m(j)~=0))*(n(j)+1)/pi); &~CI<\o P end ]kSG R end Vr}'.\$ % END: Compute the Zernike Polynomials tw;}jh %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% *@5 @,=d =bOW~0Z1 6Mf0`K % Compute the Zernike functions: 1zv'.uu., % ------------------------------ 4RO}<$Nx} idx_pos = m>0; ?`s8 pPc4 idx_neg = m<0; 9{l}bu/u G{}VPcrbC RZLq]8pM z = y; lA]8&+,ZM if any(idx_pos) Ml_^
`vn z(:,idx_pos) = y(:,idx_pos).*sin(theta*m(idx_pos)'); ?s01@f# end uRvP hkqm if any(idx_neg) u9e@a9c z(:,idx_neg) = y(:,idx_neg).*cos(theta*m(idx_neg)'); @ Y+oiB~Y end ^qs $v06 SUiOJ[5, D*jM1w_` % EOF zernfun 4?kcv59
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