| 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, *k$[/{S1- 我输入10阶的n、m,r,theta为38025*1向量,最后得到的z是29525*10阶的矩阵, ~z[`G#dU 这个,跟我们用zygo干涉仪直接拟合出的36项zernike系数,有何关系呢? yUoR6w 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? BU
nujC C* `WMP* LPs%^*8(2 37bMe@W _S!^=9bJ function z = zernfun(n,m,r,theta,nflag) J%|?[{rO{' %ZERNFUN Zernike functions of order N and frequency M on the unit circle. &lc@]y8 % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N PA2}4` % and angular frequency M, evaluated at positions (R,THETA) on the N,t9X7G& % unit circle. N is a vector of positive integers (including 0), and w0QtGQ| % M is a vector with the same number of elements as N. Each element ,f03TBD} % k of M must be a positive integer, with possible values M(k) = -N(k) o'Bd. B % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, /"m s % and THETA is a vector of angles. R and THETA must have the same ZlV % length. The output Z is a matrix with one column for every (N,M) vrn4yHoZ % pair, and one row for every (R,THETA) pair. SA,~q& % wl=tN{R % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike O7.V>7Y9H % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), Z'o0::k % with delta(m,0) the Kronecker delta, is chosen so that the integral /E>;O47a % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, Gz`Jzh
j % and theta=0 to theta=2*pi) is unity. For the non-normalized ;R$G.5h % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. #83 % KdNo'*;U]_ % The Zernike functions are an orthogonal basis on the unit circle. "2e3 <:$ % They are used in disciplines such as astronomy, optics, and o)Q4+njT@ % optometry to describe functions on a circular domain. b1xE;0uR % *oO%+6nL % The following table lists the first 15 Zernike functions. :kZ]Swi 5 % 'r'=%u$1C % n m Zernike function Normalization bLT3:q#s % -------------------------------------------------- deVd87;@7[ % 0 0 1 1 =lNW1J\SW % 1 1 r * cos(theta) 2 ];.5*a%* % 1 -1 r * sin(theta) 2 3mgvWR % 2 -2 r^2 * cos(2*theta) sqrt(6) (lsG4&\0F % 2 0 (2*r^2 - 1) sqrt(3) -e_fn&2,Y % 2 2 r^2 * sin(2*theta) sqrt(6) ^!['\ % 3 -3 r^3 * cos(3*theta) sqrt(8) F6{g{
B % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) $G=^cNB|JB % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) NF$6yv9C % 3 3 r^3 * sin(3*theta) sqrt(8) ]36SF5<0r
% 4 -4 r^4 * cos(4*theta) sqrt(10) H )X[%+ % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) 81RuNs] % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) T*p7[}# % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) R ENCk( % 4 4 r^4 * sin(4*theta) sqrt(10) DVQr7tQf % -------------------------------------------------- \Y xG % ft"- % Example 1: GtRpgM % a$W
O}g? % % Display the Zernike function Z(n=5,m=1) o*T?f)_[p % x = -1:0.01:1; <?7CwW % [X,Y] = meshgrid(x,x); tbQY&TO1 % [theta,r] = cart2pol(X,Y); AB=%yM7V* % idx = r<=1; COi15( G2 % z = nan(size(X)); h]zok}$ % z(idx) = zernfun(5,1,r(idx),theta(idx)); l6zAMyau5 % figure `JIp$ % pcolor(x,x,z), shading interp Ehy(;n)\ % axis square, colorbar <n_?$ TJ % title('Zernike function Z_5^1(r,\theta)') U=v>gNba % (4Db%Iw % Example 2: ;v8TT}R % c{'Z.mut % % Display the first 10 Zernike functions M:O*_>KF % x = -1:0.01:1; i7RK*{ % [X,Y] = meshgrid(x,x); CI+)0=`<1B % [theta,r] = cart2pol(X,Y);
Z%#e* O0 % idx = r<=1; zBm~ J% % z = nan(size(X)); U/c+j{=~ % n = [0 1 1 2 2 2 3 3 3 3]; l(Y32]Z % m = [0 -1 1 -2 0 2 -3 -1 1 3]; fD%/]`y % Nplot = [4 10 12 16 18 20 22 24 26 28]; \m`IgP* % y = zernfun(n,m,r(idx),theta(idx)); TT/=0^" % figure('Units','normalized') J
rK{MhO % for k = 1:10 2 % z(idx) = y(:,k); ,WdSJ BK'a % subplot(4,7,Nplot(k)) 58?WO} % pcolor(x,x,z), shading interp 7L+Wj }m % set(gca,'XTick',[],'YTick',[]) \Vv)(/q { % axis square hl[<o<`Q % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) u%L6@M2 % end A._CCou % NO/$}vw % See also ZERNPOL, ZERNFUN2. fq1w <e [\F:NLjiUy ,T;sWl % Paul Fricker 11/13/2006 wgDAb#Zuk "eoPG#]& /XG7M=A$o <F`9;WX eDo4>k"5 % Check and prepare the inputs: 6oKlr,. % ----------------------------- .KYs5Qu if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) TrZ!E`~ error('zernfun:NMvectors','N and M must be vectors.') ]V fp,"op end 2w8YtM3+"z [YQtX_;w };2Lrz9< if length(n)~=length(m) va~:Ivl-) error('zernfun:NMlength','N and M must be the same length.') e?\Od}Hbw end ]Y
&
2& Y&VypZ"G> AU*]D@H n = n(:); [L7S`Z m = m(:); (*26aMp if any(mod(n-m,2)) I9TNUZq(' error('zernfun:NMmultiplesof2', ... ~+\A4BW 'All N and M must differ by multiples of 2 (including 0).') 5m;pHgkb end wPyc?:|KD? m:EYOe,w zBrIhL]95 if any(m>n) 7|Qb}[s error('zernfun:MlessthanN', ... ABEEJQ 'Each M must be less than or equal to its corresponding N.') 823y; end Q2|6W E 8}z PDs L7II>^"B if any( r>1 | r<0 ) R]kH$0` error('zernfun:Rlessthan1','All R must be between 0 and 1.') d6W&u~ end Ux,dj8=o 8=\k<X{` ~9fTs4U if ( ~any(size(r)==1) ) || ( ~any(size(theta)==1) ) v&^N +>p error('zernfun:RTHvector','R and THETA must be vectors.') TDtHRhq7 end { F0"U= hO3C _} "|
oW6@ r = r(:); BZQJ@lk5 theta = theta(:); IxP$lx length_r = length(r); =c[mch%E if length_r~=length(theta)
*!EHs04 error('zernfun:RTHlength', ... a
8jG')zg 'The number of R- and THETA-values must be equal.') F fzY3r+
end wZ8LY; R[lA@q:
m<9W# % Check normalization: zHj_q%A % -------------------- $L"-JNS if nargin==5 && ischar(nflag) 3'Z+PPd!
isnorm = strcmpi(nflag,'norm'); el0W0T if ~isnorm YAF0I%PYU error('zernfun:normalization','Unrecognized normalization flag.') 7`X9s~B end =1kjKE ! else iu,Bmf^oD isnorm = false; dZbG#4oO end XG6UV(' HPWjNwM s&OwVQ<M %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Boa?Ghg % Compute the Zernike Polynomials #lm1"~`5 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% "Zicac@N K[|d7e v3jx2Z % Determine the required powers of r: t#J
#DyY5 % ----------------------------------- d7QQ5FiB m_abs = abs(m); mCpoaGV_ rpowers = []; BUKh5L for j = 1:length(n) vCNYqa)m: rpowers = [rpowers m_abs(j):2:n(j)]; e.g$|C^$m end
o;:a6D`
rpowers = unique(rpowers); Ie;}k;?- KK*"s^L )%OV|\5# % Pre-compute the values of r raised to the required powers, 4B8{\"6 % and compile them in a matrix: hE/y"SP3 % ----------------------------- I1(,J if rpowers(1)==0 WS0RvBvb rpowern = arrayfun(@(p)r.^p,rpowers(2:end),'UniformOutput',false); <BN)>NqM rpowern = cat(2,rpowern{:}); ~#~Kxh rpowern = [ones(length_r,1) rpowern]; ,Gd8 < | |