idct.rar_IDCT_matlab idct

%-------------------------------------------------------------------------- %函数名称 % idc_ek %输入参数 % f 一维数组的傅立叶变换 %输出变量 % g 输出离散余弦逆变换结果 %说明 % 对离散余弦变换的结果进行逆变换 % 点数为2的幂 %-------------------------------------------------------------------------- function g = idct_ek(f) length_f = length(f); %向量的长度N = length_x length_f_twice = 2 * length_f; %原数据点数的2倍 l = log2(length_f); % N = 2^l %----------------------把输入x补零扩展成原来的2倍-------------------------- F = zeros(1,length_f_twice); %for k = 1:length_f_twice %F(k) = 0 + 0i; for k = 1:length_f %real(F(k)) = f(k) * cos((k-1)*pi/length_f_twice) ; %imag(F(k)) = f(k) * sin((k-1)*pi/length_f_twice) ; F(k) = f(k) * cos((k-1)*pi/length_f_twice) + f(k) * sin((k-1)*pi/length_f_twice) * i; end %--------------------对扩展后的数据进行快速傅立叶变换---------------------- %Y = zeros(1,length_f_twice); Y = ifft_ek(F); %----------------------------调整系数-------------------------------------- coff = sqrt(2/length_f); coff_0 = (sqrt(1/length_f) - coff) * (f(1)); for k = 1:1:length_f g(k) = coff_0 + real(Y(k)) * length_f_twice * coff; end