| 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, vQE` c@^{ 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, 15RI(BN 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? $XtV8 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? NO%|c|B| }"!6Xm Ji)%Y5F
"`H=AX0 4"`=hu Q function z = zernfun(n,m,r,theta,nflag) @|JPE%T %ZERNFUN Zernike functions of order N and frequency M on the unit circle. aA!@;rR<yU % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N C8O7i[uc % and angular frequency M, evaluated at positions (R,THETA) on the gogl[gHO % unit circle. N is a vector of positive integers (including 0), and EVby 9! % M is a vector with the same number of elements as N. Each element lU>)n % k of M must be a positive integer, with possible values M(k) = -N(k) ) >-D={ % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, f[wjur % and THETA is a vector of angles. R and THETA must have the same 89?3,k % length. The output Z is a matrix with one column for every (N,M) h/fb<jIP1 % pair, and one row for every (R,THETA) pair. ^*j[&:d % _CYmG"mY % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike :K
a^ % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), {3_F fsg` % with delta(m,0) the Kronecker delta, is chosen so that the integral 4'7
v!I9 % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, vUA)#z< % and theta=0 to theta=2*pi) is unity. For the non-normalized u k>q\j % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. LL6ON
} % 6ba2^3GH % The Zernike functions are an orthogonal basis on the unit circle. i:NJ>b % They are used in disciplines such as astronomy, optics, and 0Te)s3X % optometry to describe functions on a circular domain. !ds"88:5^ % Q7OnhGA % The following table lists the first 15 Zernike functions. QqT6P`0u % 3:z4M9f % n m Zernike function Normalization >*ha#PE % -------------------------------------------------- s0`]!7D< % 0 0 1 1 `:B % 1 1 r * cos(theta) 2 3<Pyr-z h % 1 -1 r * sin(theta) 2 H@OrX % 2 -2 r^2 * cos(2*theta) sqrt(6) _
cHV3cz % 2 0 (2*r^2 - 1) sqrt(3) bHlD m~5 % 2 2 r^2 * sin(2*theta) sqrt(6) a`GN@
8 % 3 -3 r^3 * cos(3*theta) sqrt(8) D{3 x}5 % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) %<bG%V( % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) nATfmUN
L % 3 3 r^3 * sin(3*theta) sqrt(8) %^)Ja EUC % 4 -4 r^4 * cos(4*theta) sqrt(10) ~ L i% % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) 6O[wVaC1u % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) Oujlm| % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) !Sr0Im0 % 4 4 r^4 * sin(4*theta) sqrt(10) :p*ojl| % -------------------------------------------------- #E~WVTOw % yScov)dp( % Example 1: OL6xMToP % 1zEZ\G % % Display the Zernike function Z(n=5,m=1) u"
NIG % x = -1:0.01:1; CzDR% v x % [X,Y] = meshgrid(x,x); SBYMDKZ % [theta,r] = cart2pol(X,Y); u3v6$CD? % idx = r<=1; 3T.M?UG> % z = nan(size(X)); 3Wtv+L7Br % z(idx) = zernfun(5,1,r(idx),theta(idx)); X?k V1 % figure s5Bmv\e.i5 % pcolor(x,x,z), shading interp y:|Xg0Kp % axis square, colorbar fuIv,lDA % title('Zernike function Z_5^1(r,\theta)') e8ig[:B>+ % #|*,zIYo % Example 2: V?L$ys % $'mB 8 S % % Display the first 10 Zernike functions wDC/w[4: % x = -1:0.01:1; #Ot*jb1 % [X,Y] = meshgrid(x,x); %?9r (& % [theta,r] = cart2pol(X,Y); *Yk8Mj^_h % idx = r<=1; %JA&O % z = nan(size(X)); &4Iqm( % n = [0 1 1 2 2 2 3 3 3 3]; 1p"EE~v % m = [0 -1 1 -2 0 2 -3 -1 1 3]; +68K[s,FD % Nplot = [4 10 12 16 18 20 22 24 26 28]; Cx3m\
\c % y = zernfun(n,m,r(idx),theta(idx)); -aeo7C % figure('Units','normalized') {-7yZ]OO$ % for k = 1:10 y:6'&`L % z(idx) = y(:,k); ^*UfCoj9Z % subplot(4,7,Nplot(k)) D A)0Y_ % pcolor(x,x,z), shading interp J7xT6Q= % set(gca,'XTick',[],'YTick',[]) %F]9^C+ % axis square BQJ`vIa % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) EwBN+v;) % end "VVR#H}{ % _=^hnv % See also ZERNPOL, ZERNFUN2. 5`{;hFl :R*^Izs= ';CuJXAj % Paul Fricker 11/13/2006 )D-.7m.v] 6Cv2>'{S ?`*-QG} )s7 Tv#[ )PoI~km % Check and prepare the inputs: jvQ+u L % ----------------------------- JE:n`l/p if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) !}Ou|r4_ error('zernfun:NMvectors','N and M must be vectors.') Xgth|C}k end /$.vHt5nt "M#`y!__ HF=C8ZtlL if length(n)~=length(m) a4qpnr]0 error('zernfun:NMlength','N and M must be the same length.') 'GdlqbX(% end xS-nO_t 'E }br<2?y, &*:)5F5 n = n(:); x^#{2}4u m = m(:); qsRfG~Cg if any(mod(n-m,2)) C`T5d error('zernfun:NMmultiplesof2', ... V7'x?
pt 'All N and M must differ by multiples of 2 (including 0).') gsq[ 9 end >,]e[/p *]| JX& 714nUA872 if any(m>n) it|:P error('zernfun:MlessthanN', ... vKOn7 'Each M must be less than or equal to its corresponding N.') b|@op>UZ end S^`9[$KH0 ieLN;)Iy^ W9m[>-Ew if any( r>1 | r<0 ) H_f2:Za error('zernfun:Rlessthan1','All R must be between 0 and 1.') 4k?JxA) end ./*,Thc ^F0jI5j ). LuQ
M$/i if ( ~any(size(r)==1) ) || ( ~any(size(theta)==1) ) PL_wa(}y]D error('zernfun:RTHvector','R and THETA must be vectors.') e6xjlaKb end *_rGBW |nZB/YZt v6Wf7)d/1 r = r(:); 4^}PnU7z theta = theta(:); dQ~"b= length_r = length(r); sW3D
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n if length_r~=length(theta) N6
(w<b error('zernfun:RTHlength', ... qa`(,iN 'The number of R- and THETA-values must be equal.') aYCzb7 end kL2sJX+ MCpK^7]k ^M5uLm-_s % Check normalization: `rJ ~*7- % -------------------- gm$MEeC if nargin==5 && ischar(nflag) |Qm%G\oB? isnorm = strcmpi(nflag,'norm'); QD VA*6F if ~isnorm \gv
x)S11 error('zernfun:normalization','Unrecognized normalization flag.') J|8YB3K, end x&b-Na | |