cdfspline.m Filter coefficients for Cohen, Daubechies, Faveau biorth spline filters Usage : [h0,g0] = cdfspline(N,M) h0 - bspline poly of order N g0 - poly using rest of factors from daubpoly((N+M)/2) h0 and g0 are scaling filters Written by : Justin Romberg Created : 3/23/2004
0001 % cdfspline.m 0002 % 0003 % Filter coefficients for Cohen, Daubechies, Faveau biorth spline filters 0004 % Usage : [h0,g0] = cdfspline(N,M) 0005 % h0 - bspline poly of order N 0006 % g0 - poly using rest of factors from daubpoly((N+M)/2) 0007 % h0 and g0 are scaling filters 0008 % 0009 % Written by : Justin Romberg 0010 % Created : 3/23/2004 0011 0012 function [h0, g0] = cdfspline(N, M) 0013 0014 0015 if (mod(N+M,2) ~= 0) 0016 error('N+M must be even.') 0017 end 0018 0019 0020 [P, Q] = daubpoly((N+M)/2); 0021 qr = roots(Q); 0022 0023 h0r = -ones(N,1); 0024 g0r = [-ones(M,1); qr]; 0025 0026 h0p = poly(h0r); 0027 g0p = poly(g0r); 0028 h0 = [zeros(1,M-1) sqrt(2)*h0p/sum(h0p) zeros(1,M-1)]; 0029 g0 = sqrt(2)*g0p/sum(g0p); 0030 0031