| 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, @&>
+`kgU- 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, g
0=t9J 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? i<![i5uAI 那些系数是通过对29525*10阶的矩阵每列的值算出来的嘛? OPh@H.)^ sTY l' Ieg 0M.[) @ 2M`Ni&v |,f6c
Omf function z = zernfun(n,m,r,theta,nflag) >qZRIDE5$ %ZERNFUN Zernike functions of order N and frequency M on the unit circle. l,8|E % Z = ZERNFUN(N,M,R,THETA) returns the Zernike functions of order N I[ C.iILL % and angular frequency M, evaluated at positions (R,THETA) on the w-/Tb~#E % unit circle. N is a vector of positive integers (including 0), and [a6lE"yr % M is a vector with the same number of elements as N. Each element Fm{y.URo
% k of M must be a positive integer, with possible values M(k) = -N(k) 3".W % to +N(k) in steps of 2. R is a vector of numbers between 0 and 1, bsVOO9.4- % and THETA is a vector of angles. R and THETA must have the same % QkvBg* % length. The output Z is a matrix with one column for every (N,M) ,^T2hY` % pair, and one row for every (R,THETA) pair. r73Xh"SL % 81g0oVv % Z = ZERNFUN(N,M,R,THETA,'norm') returns the normalized Zernike /iy/2x28> % functions. The normalization factor sqrt((2-delta(m,0))*(n+1)/pi), )E|Bb=% % with delta(m,0) the Kronecker delta, is chosen so that the integral 93,ExgFt % of (r * [Znm(r,theta)]^2) over the unit circle (from r=0 to r=1, CiFbk&-g % and theta=0 to theta=2*pi) is unity. For the non-normalized v]sGdZ(6- % polynomials, max(Znm(r=1,theta))=1 for all [n,m]. xbIA97g-O, % o)DKP>IM# % The Zernike functions are an orthogonal basis on the unit circle. **[p{R]8o % They are used in disciplines such as astronomy, optics, and }%|OnEk" % optometry to describe functions on a circular domain. ],m-,K % _l<"Qqt % The following table lists the first 15 Zernike functions. 7dIDKx % dY^~^<{Lj % n m Zernike function Normalization S([De"y % -------------------------------------------------- zSO9 U % 0 0 1 1 ==9Ez % 1 1 r * cos(theta) 2 1owoh,V6 % 1 -1 r * sin(theta) 2 =X):Zi % 2 -2 r^2 * cos(2*theta) sqrt(6) Pr"ESd>Y % 2 0 (2*r^2 - 1) sqrt(3) <Do89 % 2 2 r^2 * sin(2*theta) sqrt(6) 8iB}a\]B % 3 -3 r^3 * cos(3*theta) sqrt(8) >@o*v*25 % 3 -1 (3*r^3 - 2*r) * cos(theta) sqrt(8) s,8%;\!C % 3 1 (3*r^3 - 2*r) * sin(theta) sqrt(8) a1&^P1. % 3 3 r^3 * sin(3*theta) sqrt(8) yo=d"*E4^ % 4 -4 r^4 * cos(4*theta) sqrt(10) %8/$CR % 4 -2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) O5w\oDhMb % 4 0 6*r^4 - 6*r^2 + 1 sqrt(5) E&AR=yqk % 4 2 (4*r^4 - 3*r^2) * cos(2*theta) sqrt(10) "`wq:$R % 4 4 r^4 * sin(4*theta) sqrt(10) "k/x+%!Spc % -------------------------------------------------- %|~UNP$ % 6W o7q\ " % Example 1: wO9<An % Q*5d~Yr ]R % % Display the Zernike function Z(n=5,m=1) =v}.sJ V? % x = -1:0.01:1; 1['A1, % [X,Y] = meshgrid(x,x); qn . % [theta,r] = cart2pol(X,Y); EOiKwhrV % idx = r<=1; K`sm % z = nan(size(X)); m[XN,IE#u % z(idx) = zernfun(5,1,r(idx),theta(idx)); 0ni5 :tYy % figure l%O-c}X % pcolor(x,x,z), shading interp ueOvBFgZ % axis square, colorbar n >^?BU % title('Zernike function Z_5^1(r,\theta)') ? "gy`oCv % r_",E=e % Example 2: U7N<!6 % 4C$,X!kzF % % Display the first 10 Zernike functions w>eOERZa % x = -1:0.01:1; ;-F#a+2]! % [X,Y] = meshgrid(x,x); gVc[`(@h % [theta,r] = cart2pol(X,Y); l d@^$ % idx = r<=1; ^/,s$dj % z = nan(size(X)); w K+2;*bI % n = [0 1 1 2 2 2 3 3 3 3]; pfG:PrZ % m = [0 -1 1 -2 0 2 -3 -1 1 3]; {+ m)*3~w % Nplot = [4 10 12 16 18 20 22 24 26 28]; .T7ciD % y = zernfun(n,m,r(idx),theta(idx)); f55Ev<oOa % figure('Units','normalized') Cn,dr4J[ % for k = 1:10 :5(TOF % z(idx) = y(:,k); kF5}S8B % subplot(4,7,Nplot(k)) n\ZFPXP % pcolor(x,x,z), shading interp
Qj~0vx! % set(gca,'XTick',[],'YTick',[]) w?[)nlNW % axis square c:bB4ch} % title(['Z_{' num2str(n(k)) '}^{' num2str(m(k)) '}']) fAK % end l/]P6 @N % >wn&+%i& % See also ZERNPOL, ZERNFUN2. 9/{g%40B^ <:p&P J]%P
fWV % Paul Fricker 11/13/2006 5]{YERa' .F]6uXd IRQ(/:] Gp14; #
;9KDt@ % Check and prepare the inputs: O;XF'r_ % ----------------------------- #X)s=Y&5!T if ( ~any(size(n)==1) ) || ( ~any(size(m)==1) ) *6h.#$\ error('zernfun:NMvectors','N and M must be vectors.') mb#)w`< end \ l:n _CgD7d &I70veNY if length(n)~=length(m) @U&|38 error('zernfun:NMlength','N and M must be the same length.') 6O"0?wG+ end k`?n("j oyHjdPdY# $R^"~|m3M n = n(:); Y3thW@mD05 m = m(:); A4#m&o | |