Texas Instruments Corporation

Daniel L Zelazo

Steven David Trautmann

Atsuhiro Sakurai

Steven D Trautman

A system for sharing wavelet domain components among encoded signals receives a set of signals decomposed and encoded according to a wavelet transform. The decomposed and encoded signals each include a set of wavelet coefficients at each level of the decomposition of the encoded signal. Using a vector quantization technique, the system identifies one or more sets of wavelet coefficients that are sharable among two or more of the decomposed and encoded signals at a particular level of decomposition. The system then stores the sets of wavelet coefficients of the decomposed and encoded signals. Each identified sharable set of wavelet coefficients at a particular level of decomposition is stored only once and shared by two or more of the decomposed and encoded signals.

Sharing wavelet domain components among encoded signals

A signal processing device includes a biorthogonal filter bank that processes a finite length signal including a left boundary and a right boundary. The biorthogonal filter bank includes an analysis filter bank. The analysis filter bank includes one or more left boundary filters, one or more right boundary filters, and one or more steady-state analysis filters. Each left boundary filter and each right boundary filter includes a row vector. The left and right boundary filters have been designed by generating, from the steady-state analysis filters, an analysis matrix representing the analysis filter bank, multiplying the analysis matrix by a permutation matrix to generate a permutated analysis matrix, truncating the permutated analysis matrix to a degree to generate a rectangular truncated analysis matrix, and selecting a number of left boundary filters and a number of right boundary filters such that, when the row vectors corresponding to the number of left boundary filters and the number of right boundary filters are added to the truncated analysis matrix, the truncated analysis matrix becomes square. Each row vector added to the truncated analysis matrix lies outside a row space of the truncated analysis matrix such that a row vector specifies a permissible design for a boundary filter. The biorthogonal filter bank also includes a synthesis filter bank corresponding to the analysis filter bank. The synthesis filter bank includes a number of left boundary filters, a number of right boundary filters, and a number of steady-state synthesis filters. A synthesis matrix specifies the left boundary filters, right boundary filters, and steady-state synthesis filters of the synthesis filter bank. The synthesis matrix has been created by calculating the dual, or inverse, of the square analysis matrix.

Designing boundary filters for a biorthogonal filter bank

Efficient reconstruction of a discrete signal in a range from subband coefficients of multirate analysis filtering translates the range into required input coefficient ranges and minimizes computation and memory access.

Efficient reconstruction

A time scale modification method employs separate bands obtained through an analysis polyphase filter bank with separate time-scale modification processing for the bands. The outputs are combined using a synthesis filter bank. Some constraints are imposed on the time-scale modification processing, such a limitation of the range of overlap adjustment values for bands other than the greatest energy band, to eliminate noise due to aliasing and inter-channel phase mismatch. This invention produces output quality considerably higher than conventional time-domain time-scale modification methods for general music signals with computational requirements comparable to those of conventional time-domain time-scale modification methods.

Growing community of inventors

Kasiwa, Japan

Daniel L Zelazo