| 摘要 |
The encoding and decoding of HOA signals using Singular Value Decomposition includes forming (11) based on sound source direction values and an Ambisonics order corresponding ket vectors (| Y (© s )Œª) of spherical harmonics and an encoder mode matrix (ž O x S ). From the audio input signal (| x (© s )Œª) a singular threshold value ( à µ ) determined. On the encoder mode matrix a Singular Value Decomposition (13) is carried out in order to get related singular values which are compared with the threshold value, leading to a final encoder rank ( r fin e ) . Based on direction values (© l ) of loudspeakers and a decoder Ambisonics order ( N l ), corresponding ket vectors (|Y(© l )Œª) and a decoder mode matrix (¨ O x L ) are formed (18). On the decoder mode matrix a Singular Value Decomposition (19) is carried out, providing a final decoder rank ( r fin d ). From the final encoder and decoder ranks a final rank is determined, and from this final rank and the encoder side Singular Value Decomposition an adjoint pseudo inverse (ž + ) € of the encoder mode matrix (ž O x S ) and an Ambisonics ket vector (|a' s Œª) are calculated. The number of components of the Ambisonics ket vector is reduced (16) according to the final rank so as to provide an adapted Ambisonics ket vector (|a' l Œª). From the adapted Ambisonics ket vector, the output values of the decoder side Singular Value Decomposition and the final rank an adjoint decoder mode matrix (¨) € is calculated (15), resulting in a ket vector (| y (© l )Œª) of output signals for all loudspeakers. |
