| 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, 'ROz| iJ 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, 7(h@5 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? RJerx:] 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? RtHai[j NW`.7'aWT h4|}BGO ./Ek+p*96H R#;xBBt8 function z = zernfun(n,m,r,theta,nflag) {j]cL!Od %ZERNFUN Zernike functions of order N and frequency M on the unit circle. @P75f5p}< % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N ;
YQB % and angular frequency M, evaluated at positions (R,THETA) on the F!)[H["_ % unit circle. N is a vector of positive integers (including 0), and d4\JM 65 % M is a vector with the same number of elements as N. Each element un-%p# % k of M must be a positive integer, with possible values M(k) = -N(k) uyB 2 % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, &,jUaC5I % and THETA is a vector of angles. R and THETA must have the same &;P\e % length. The output Z is a matrix with one column for every (N,M) 'r%(,=L % pair, and one row for every (R,THETA) pair. l/zv > % >Jx=k"Kv+ % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike 6LGl]jHf % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), M57<e`m % with delta(m,0) the Kronecker delta, is chosen so that the integral W4 d32+V % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, %,02i@Fc % and theta=0 to theta=2*pi) is unity. For the non-normalized }s<;YC % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. ^GY^g-R % (Q%
@] % The Zernike functions are an orthogonal basis on the unit circle. h`N2M, % They are used in disciplines such as astronomy, optics, and $o5i15Oy. % optometry to describe functions on a circular domain. ZlMT) ~fM& % XL.f`N.O % The following table lists the first 15 Zernike functions. W7
Iy _> % }k%6X@ % n m Zernike function Normalization } f&=} % -------------------------------------------------- $[fq Th % 0 0 1 1 d!R+-Fp % 1 1 r * cos(theta) 2 g*YA~J@ % 1 -1 r * sin(theta) 2 # M/n\em"X % 2 -2 r^2 * cos(2*theta) sqrt(6) 7:uz{xPK6 % 2 0 (2*r^2 - 1) sqrt(3) 7R:Ij[dV % 2 2 r^2 * sin(2*theta) sqrt(6) M3@qhEf?vk % 3 -3 r^3 * cos(3*theta) sqrt(8) &k}B66 % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) Ul]7IUzsu % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) fv8x7l7 % 3 3 r^3 * sin(3*theta) sqrt(8) L@AFt)U % 4 -4 r^4 * cos(4*theta) sqrt(10) Eq;w5;7s % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) [ R+M .5 % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) HOWpTu( % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) CV"}(1T % 4 4 r^4 * sin(4*theta) sqrt(10) q/I( e % -------------------------------------------------- *|\bS " % 16 `M=R % Example 1: 7JQ4*RM % b,~pwbHf % % Display the Zernike function Z(n=5,m=1) MT>(d*0s % x = -1:0.01:1; 1[Yl8W%pj % [X,Y] = meshgrid(x,x); Y3:HQ0w`| % [theta,r] = cart2pol(X,Y); ]9w)0iH % idx = r<=1; _p0Yhju? % z = nan(size(X)); qX-5/;n % z(idx) = zernfun(5,1,r(idx),theta(idx)); e3CFW_p % figure eu$VKLY* % pcolor(x,x,z), shading interp N^[
F+y % axis square, colorbar #1'q'f:7& % title('Zernike function Z_5^1(r,\theta)') TCyev[( % TU~y;:OJ % Example 2: N^oP,^+U % zi6J|u % % Display the first 10 Zernike functions ^lV}![do! % x = -1:0.01:1; #
2^H{7 % [X,Y] = meshgrid(x,x); \^dse % [theta,r] = cart2pol(X,Y); }a5TY("d9H % idx = r<=1; v;
#y^O
% z = nan(size(X)); `
wEX; % n = [0 1 1 2 2 2 3 3 3 3]; "0;WYw? % m = [0 -1 1 -2 0 2 -3 -1 1 3]; k0V]<#h87 % Nplot = [4 10 12 16 18 20 22 24 26 28]; Qv~@ % y = zernfun(n,m,r(idx),theta(idx)); /fT"WaTEK % figure('Units','normalized') /FXvrH( % for k = 1:10 oz=ULPZ%
% z(idx) = y(:,k); _dk[k@5W{' % subplot(4,7,Nplot(k)) BE@(| U % pcolor(x,x,z), shading interp COHBjufmR % set(gca,'XTick',[],'YTick',[]) (jU_lsG % axis square Ss5@ n % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) '1b8>L % end 8o|C43Q_ % }1 qQ7}v % See also ZERNPOL, ZERNFUN2. >uYQt~s nsi?.c&0! $nmt&lm % Paul Fricker 11/13/2006 AH'c:w]~ sv%E5@ nrev!h u=qK_$d4 1ds4C:M+< % Check and prepare the inputs: l59\Lo: % ----------------------------- }W 5ks-L6 if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) oc,I,v error('zernfun:NMvectors','N and M must be vectors.') [UzacX t end c8mh#Tbl #p*uk o[Qb/ 7 if length(n)~=length(m) #OM'2@ error('zernfun:NMlength','N and M must be the same length.') Q+Q"J U end qQ)1+^ =6ru%.8U, Ip7#${f5M n = n(:); LRu*%3xx m = m(:); [5IbR9_ if any(mod(n-m,2)) ELnUpmv\ error('zernfun:NMmultiplesof2', ... /Lr`Aka5 'All N and M must differ by multiples of 2 (including 0).') +i!HMyM end !`Kg&t [&V 8f~x\. 2C:u)}R7D if any(m>n) !YGHJwW: error('zernfun:MlessthanN', ... dO z|CfUhI 'Each M must be less than or equal to its corresponding N.') {~9HJDcM end |0}Xb|+ Ot47.z G.L}VpopM if any( r>1 | r<0 ) 5%9Uh'y# error('zernfun:Rlessthan1','All R must be between 0 and 1.') Iv3O8GU end y[l{
UBue: 9jf9u0 Pi5MFw'v if ( ~any(size(r)==1) ) || ( ~any(size(theta)==1) ) ly34aD/p~, error('zernfun:RTHvector','R and THETA must be vectors.') .F@Lx45 end Xux[ 0|-}>>qb\ iB
W:t r = r(:); U`3?bhzua theta = theta(:); '"7b;%EN' length_r = length(r); `.JW_F)1 if length_r~=length(theta) T5}3Y3G,6 error('zernfun:RTHlength', ... YC 4c-M 'The number of R- and THETA-values must be equal.') ]8 }2 end ,_(=w.F
bf.+Ewb( V*s\ ~h) % Check normalization: jEQ_#KKYJ % --------------------
W^^0Rh_ if nargin==5 && ischar(nflag) =/'>.p3/S isnorm = strcmpi(nflag,'norm'); a"xRc if ~isnorm 3 $%#n* error('zernfun:normalization','Unrecognized normalization flag.') VFZyWX@#u end dL4VcUS. else gh[q*%# isnorm = false; X:`=\D end X4:84 5s^vC2$) $H3C/| %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% GjW(&p$& % Compute the Zernike Polynomials ]!S#[Wt {k %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 0&NM=~ y~]D402Cx V}<<?_ % Determine the required powers of r: Rh6CV % ----------------------------------- d!<>Fh^6, m_abs = abs(m);
c %Y*XJ' rpowers = []; [V?HK_~ for j = 1:length(n) r%=a :GdAg rpowers = [rpowers m_abs(j):2:n(j)]; L=Aj+ end ]g9SUFM rpowers = unique(rpowers); BR@gJ(2
vxPr)"Vvz rr`_\ut % Pre-compute the values of r raised to the required powers, %jj-\Gz! % and compile them in a matrix: _G-6G=q % ----------------------------- ;9)nG,P3 if rpowers(1)==0 [?<v|k
rpowern = arrayfun(@(p)r.^p,rpowers(2:end),'UniformOutput',false); 3nhQ^zqf rpowern = cat(2,rpowern{:}); 7`L]aRS[ rpowern = [ones(length_r,1) rpowern]; @~$=96^ else /-lW$.+{? rpowern = arrayfun(@(p)r.^p,rpowers,'UniformOutput',false); lws.;abm%n rpowern = cat(2,rpowern{:}); .XK3o .ZhW end U<XfO'XJ aW|=|K j3w~2q"r % Compute the values of the polynomials: &~.|9P/45 % -------------------------------------- `3[W~Cq y = zeros(length_r,length(n)); Z[z" v for j = 1:length(n) G
DBV s = 0:(n(j)-m_abs(j))/2; A;ZluQ pows = n(j):-2:m_abs(j); 0#yH<h$ for k = length(s):-1:1 *R4=4e2#S p = (1-2*mod(s(k),2))* ... h8M}} prod(2:(n(j)-s(k)))/ ... Tp~Qg{%Og prod(2:s(k))/ ... m#Z9wf] F prod(2:((n(j)-m_abs(j))/2-s(k)))/ ... po]<sB prod(2:((n(j)+m_abs(j))/2-s(k))); *pS3xit~ idx = (pows(k)==rpowers); Ls|)SiXrY y(:,j) = y(:,j) + p*rpowern(:,idx); ~9!@BL\ end %|/\Qu j";L{ if isnorm ^Bw"+ 6d y(:,j) = y(:,j)*sqrt((1+(m(j)~=0))*(n(j)+1)/pi); H_Hr=_8}- end _8`S&[E? end 60|m3|0o % END: Compute the Zernike Polynomials rwwyYIlEg %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 6eB~S)Ko A#pH$s b4KNIP7E % Compute the Zernike functions: CIwI1VR^ % ------------------------------ %ID48_>* idx_pos = m>0; I L&PN`# idx_neg = m<0; E'+z.~+
)WEOqaR] -DZ5nx z = y; VL\Ah3+ if any(idx_pos) 6]!Jo)BF z(:,idx_pos) = y(:,idx_pos).*sin(theta*m(idx_pos)'); HsG3s?* end 0"sZP\<p if any(idx_neg) ,*L3 z(:,idx_neg) = y(:,idx_neg).*cos(theta*m(idx_neg)'); iy8Ln,4z( end j6*e^
B &u2m6 r>W ]REF1<)4z % EOF zernfun ~-yq,x
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