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, pA'4|ffwe 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, 1-8mFIK 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? CKYc\<zR0l 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? -]0OKE& Ci@o|Y }tP 8bTn^!1 \j@OZ dN$0OS`s[ function z = zernfun(n,m,r,theta,nflag) ($q-_m %ZERNFUN Zernike functions of order N and frequency M on the unit circle. Nyku4r0 % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N Ep9nsX* % and angular frequency M, evaluated at positions (R,THETA) on the |kyX3~ % unit circle. N is a vector of positive integers (including 0), and {{$Nqn,pH % M is a vector with the same number of elements as N. Each element >8~.wXyoC % k of M must be a positive integer, with possible values M(k) = -N(k) D$w6V % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, )tC5Hijq, % and THETA is a vector of angles. R and THETA must have the same zU5v /'h>d % length. The output Z is a matrix with one column for every (N,M) ep!Rf: % pair, and one row for every (R,THETA) pair. h9t$Uz^N % ^h(ew1: % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike ]AINKUI0 % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), {3|t;ZHk % with delta(m,0) the Kronecker delta, is chosen so that the integral qk%;on&` % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, k$ 4y9{ % and theta=0 to theta=2*pi) is unity. For the non-normalized :i0uPh\0 % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. Yz<3JRw % Yxr>"KH6a % The Zernike functions are an orthogonal basis on the unit circle. Tm~" IB* % They are used in disciplines such as astronomy, optics, and P{8iJ`rBG % optometry to describe functions on a circular domain. /Wi[OT14 % I,E?h?6Y % The following table lists the first 15 Zernike functions. *z5.vtfu! % 5#HW2"7 % n m Zernike function Normalization y*4=c_Z % -------------------------------------------------- 0eT(J7[ < % 0 0 1 1 JB%',J % 1 1 r * cos(theta) 2 GA$V0YQX % 1 -1 r * sin(theta) 2 e),q0%5 % 2 -2 r^2 * cos(2*theta) sqrt(6) ~8PZ5;g % 2 0 (2*r^2 - 1) sqrt(3) 1$xNUsD2 % 2 2 r^2 * sin(2*theta) sqrt(6) ~uj#4>3T % 3 -3 r^3 * cos(3*theta) sqrt(8) @3>u@ % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) !44/sr' % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) n4O]8C'lW9 % 3 3 r^3 * sin(3*theta) sqrt(8) 4-l8,@9 % 4 -4 r^4 * cos(4*theta) sqrt(10) Xe3U`P7( % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) b_$4V3TA % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) KN^=i5K+Y % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) T.])diuvj- % 4 4 r^4 * sin(4*theta) sqrt(10) [zH:1Zhl& % -------------------------------------------------- hwPw]Ln/ % `{f}3bO7C % Example 1: 4)S,3G % +cJL7=V& % % Display the Zernike function Z(n=5,m=1) Jz\%%C % x = -1:0.01:1; ZJnYIK % [X,Y] = meshgrid(x,x); _?-E7:Sw % [theta,r] = cart2pol(X,Y); -z
ID x % idx = r<=1; iJ ($YvF4 % z = nan(size(X)); Fe# 1 % z(idx) = zernfun(5,1,r(idx),theta(idx)); h}>"j%I % figure {dhXIs % pcolor(x,x,z), shading interp =Z{O<xw' % axis square, colorbar ?1*cO:O % title('Zernike function Z_5^1(r,\theta)') ^-TE([ bW % /74QMx? % Example 2: ;(b9#b. % 1gE [v % % Display the first 10 Zernike functions zUt'QH7E. % x = -1:0.01:1; y;4OY % [X,Y] = meshgrid(x,x); 6,^>mNm % [theta,r] = cart2pol(X,Y); WEw6He; % idx = r<=1; %2}-2}[> % z = nan(size(X)); 5us:adm[pD % n = [0 1 1 2 2 2 3 3 3 3]; 6`&a&%,O % m = [0 -1 1 -2 0 2 -3 -1 1 3]; VRVO-Sk % Nplot = [4 10 12 16 18 20 22 24 26 28]; ^\hG"5# % y = zernfun(n,m,r(idx),theta(idx)); wVvF^VHV^ % figure('Units','normalized') b10cuy|a/X % for k = 1:10 MOQ6: % z(idx) = y(:,k); n"h`5p5' % subplot(4,7,Nplot(k)) 6gkV*|U,e % pcolor(x,x,z), shading interp `:ArT}F % set(gca,'XTick',[],'YTick',[]) kS %Ydy#:' % axis square TCMCK_SQL % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) +UC G0D % end raW>xOivR % W6^5YH% % See also ZERNPOL, ZERNFUN2. nxO"ua <KJ/<0l @CNi{. RX % Paul Fricker 11/13/2006 -5)H<dAQZ q?H|o( ]dF
,:8 q?Cnav`DY H!@kO]?n % Check and prepare the inputs: d.[8c=$ % ----------------------------- _H9 MwJ if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) UI0(=>L error('zernfun:NMvectors','N and M must be vectors.') ru'F6?d end ?'IP4z;y EHSlK5bD, Tg7an&# if length(n)~=length(m) ajve~8/& error('zernfun:NMlength','N and M must be the same length.') ~Q*%DRd&Z- end {k(g]#pP &]Q@7Nl7:l seba9y n = n(:); 50"pbzW m = m(:); M
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ac if any(mod(n-m,2)) *tGY6=7O error('zernfun:NMmultiplesof2', ... ov|d^)' 'All N and M must differ by multiples of 2 (including 0).') CVDV)#JA end r^2p*nr} bs+f,j-oBN XUrXnz|> if any(m>n) WEAT01 error('zernfun:MlessthanN', ... !zBhbmlKt 'Each M must be less than or equal to its corresponding N.') R1PkTZP& end 87=&^.~` }?lrU.@zg XYQ/^SI!: if any( r>1 | r<0 ) 3\AU 72- error('zernfun:Rlessthan1','All R must be between 0 and 1.') FOb0uj=(v end +20G>y=+ 6d:zb;Iz ;i4Q| if ( ~any(size(r)==1) ) || ( ~any(size(theta)==1) ) GeI-\F7b error('zernfun:RTHvector','R and THETA must be vectors.') j
'FVz& end .b_)%jd x MlcR"gl* .n TwPrG r = r(:); 85>05? theta = theta(:); 84$nT>c length_r = length(r); }pDqe;a{ if length_r~=length(theta) r=Gks=NX" error('zernfun:RTHlength', ... 9y6-/H
, 'The number of R- and THETA-values must be equal.') Y21g{$~Q{ end ) g0%{dfJ Gw=B:kGk #akpXdXs % Check normalization: FSP+?(( % -------------------- toLV4BtIG if nargin==5 && ischar(nflag) phQUD isnorm = strcmpi(nflag,'norm'); 7Sf
bx~48 if ~isnorm !1rlN8w(qr error('zernfun:normalization','Unrecognized normalization flag.') ,aOl_o -& end 'SO %)B else Moy <@+ isnorm = false; ?U%QG5/> end ^/)^7\@ I?]ohG K *lYVY)L %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% ZLc -RM % Compute the Zernike Polynomials 7X`l&7IXP %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \j+1V1t9 x`U^OLV H
>j % Determine the required powers of r: 6O|@xvg % ----------------------------------- S3F;(PDzy m_abs = abs(m); x%s-+& rpowers = []; j1^I+j) for j = 1:length(n) 63^O|y\W8 rpowers = [rpowers m_abs(j):2:n(j)]; NYt&@Z}] end 5rwu!Y;7* rpowers = unique(rpowers); PZ2;v< G"klu aL*&r~`&e' % Pre-compute the values of r raised to the required powers, B%"
d~5Y % and compile them in a matrix: WeJl4wF % ----------------------------- T m,b,hi$ if rpowers(1)==0 1G"z<v
B rpowern = arrayfun(@(p)r.^p,rpowers(2:end),'UniformOutput',false); +Um( h-; rpowern = cat(2,rpowern{:}); H0:E(}@ rpowern = [ones(length_r,1) rpowern]; WM
Fb4SUR else !_"@^?,q rpowern = arrayfun(@(p)r.^p,rpowers,'UniformOutput',false); w&X<5'GM rpowern = cat(2,rpowern{:}); BYpG end %.vQU @2A ;>#wU' Jy^u? % Compute the values of the polynomials: ;l4[%xld % -------------------------------------- :X0k]p y = zeros(length_r,length(n)); .Fs7z7?Y for j = 1:length(n) }]e-{C} s = 0:(n(j)-m_abs(j))/2; _+p4Wvu~0 pows = n(j):-2:m_abs(j); 0QFS for k = length(s):-1:1 g@rb p = (1-2*mod(s(k),2))* ... gaQdG=G8$ prod(2:(n(j)-s(k)))/ ... FFV `P prod(2:s(k))/ ... ,eOB(?Ku prod(2:((n(j)-m_abs(j))/2-s(k)))/ ... hq%?=2'9? prod(2:((n(j)+m_abs(j))/2-s(k))); t'?.8}?)I& idx = (pows(k)==rpowers); kr+D,h01 y(:,j) = y(:,j) + p*rpowern(:,idx); 0M*Z'n
+ end XnDUa3 .}&`TU if isnorm W6f/T3 y(:,j) = y(:,j)*sqrt((1+(m(j)~=0))*(n(j)+1)/pi); 'U1R\86M end FQm`~rA~zt end 9`wZz~hL" % END: Compute the Zernike Polynomials ahuGq' %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 2w59^"<, --PtZ]Z &]8P1{ % Compute the Zernike functions: LwrUQ) % ------------------------------ 5XO;N s idx_pos = m>0; l9}3XI.= idx_neg = m<0; Xp >7iX!: ,ek_R)&[o G.rrv z = y; 5Eg1Q
YVt if any(idx_pos) P=7zs;k z(:,idx_pos) = y(:,idx_pos).*sin(theta*m(idx_pos)'); Gnf~u[T6 end \!>3SKs(e if any(idx_neg) uZM{BgXXD z(:,idx_neg) = y(:,idx_neg).*cos(theta*m(idx_neg)'); `Zf^E
>) end Ge2q% OTy.VT| NYE`Kin- % EOF zernfun q
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