Fujitsu Corporation

Shunsuke Takeuchi

Yohei Kishi

Masanao Suzuki

Miyuki Shirakawa

Akira Kamano

Takeshi Otani

Yoshiteru Tsuchinaga

Nobuyuki Washio

Chisato Shioda

A device for determining a sound source direction determines a direction in which a source of a reached sound exists, based on at least one of a sound pressure difference between a first sound pressure that is a sound pressure of a first frequency component of a first part of the reached sound acquired by a first microphone and a second sound pressure that is a sound pressure of the first frequency component of a second part of the reached sound acquired by a second microphone, and a phase difference between a first phase that is a phase of a second frequency component of the first part of the reached sound and a second phase that is a phase of the second frequency component of the second part of the reached sound.

Device and method for determining a sound source direction

A plurality of candidates of prediction coefficients of a channel signal out of a plurality of channel signals are extracted from a code book storing a plurality of prediction coefficients, each candidate having a predictive error falling within a specific range of predictive error of predictive encoding of two other channel signals, and a prediction coefficient is selected from the extracted candidates as a result of the predictive encoding in accordance with a specific data embedding rule and embedding embed target data into the selected prediction coefficient.

Data embedding device, data embedding method, data extractor device, and data extraction method for embedding a bit string in target data

A device for embedding data upon a prediction coding of a multi-channel signal includes a storage unit to store a code book that includes a plurality of prediction parameter sets, each of the plurality of prediction parameter sets including a plurality of kinds of prediction parameters for a processing regarding the prediction coding. The device extracts a plurality of candidates of a prediction parameter set for the multi-channel signal from the code book, wherein the plurality of candidates are capable of suppressing a prediction error in the prediction coding within a predetermined range, converts an embedding object that is at least part of the data in accordance with a number corresponding to a number of the candidates, selects, from the plurality of candidates, the prediction parameter set corresponding to the converted embedding object, and multiplexes the selected prediction parameter set with coded data which are down-mixed from the multi-channel signal.

Device and method data for embedding data upon a prediction coding of a multi-channel signal

An orthogonal transform apparatus includes: an interchanging unit which interchanges MDCT coefficients contained in a first half of a prescribed interval with MDCT coefficients contained in a second half thereof; an inverting unit which inverts the sign of the MDCT coefficients contained in the second half of the prescribed interval after the interchange; an inverse cosine transform unit which computes the real components of QMF coefficients by applying an IMDCT using FFT to the MDCT coefficients contained in the first half and the sign-inverted MDCT coefficients contained in the second half; an inverse sine transform unit which computes the imaginary components of the QMF coefficients by applying an IMDST using FFT to the MDCT coefficients contained in the first half and the sign-inverted MDCT coefficients contained in the second half; and a coefficient adjusting unit which computes the QMF coefficients by combining the real components with the imaginary components.

Orthogonal transform apparatus, orthogonal transform method, orthogonal transform computer program, and audio decoding apparatus

An audio coding device that performs predictive coding on a third-channel signal included in a plurality of channels in an audio signal according to a first-channel signal and a second-channel signal, which are included in the plurality of channels, and to a plurality of channel prediction coefficients included in a coding book, the device includes a processor; and a memory which stores a plurality of instructions, which when executed by the processor, cause the processor to execute, selecting channel prediction coefficients corresponding to the first-channel signal and the second-channel signal so that an error, which is determined by a difference between the third-channel signal before predictive coding and the third-channel signal after predictive coding, is minimized; and controlling the first-channel signal or the second-channel signal so that the error is further reduced.

Audio coding device and method

An audio encoding device includes a processor; and a memory which stores a plurality of instructions, which when executed by the processor, cause the processor to execute, calculating first phases indicating phases of a first channel signal and a second channel signal included in audio signals of a plurality of channels; and performing, on the basis of the first phases, either first predictive coding in which a third channel signal included in the audio signals of the plurality of channels is predicted using the first channel signal and the second channel signal or second predictive coding in which the second channel signal is predicted using the first channel signal.

Audio encoding device and audio encoding method

An orthogonal transform apparatus computes either one of the real and imaginary components of the quadrature mirror filter coefficient contained in a first subinterval of a plurality of subintervals among which a coefficient sequence containing a plurality of quadrature mirror filter coefficients is divided so that the values of basis functions are symmetrically placed, by computing a sum of products of the plurality of modified discrete cosine transform coefficients and the basis functions corresponding to the subinterval, computes the other one of the real and imaginary components of the quadrature mirror filter coefficient contained in the first subinterval and the real and imaginary components of the quadrature mirror filter coefficient contained in another subintervals by performing a butterfly operation using a computed value produced as a result of the sum of products and computes each quadrature mirror filter coefficient by combining the real component and imaginary component thereof.

An audio decoding device includes a processor; and a memory which stores a plurality of instructions, which when executed by the processor, cause the processor to execute, decoding, using a first channel signal and a second channel signal included in a plurality of channels of an audio signal having a first frequency range and a second frequency range, a first prediction coefficient of the first frequency range and a second prediction coefficient of the second frequency range, both selected from a code book when prediction-encoding a third channel signal that is not subjected to prediction encoding and that is included in the plurality of channels; decoding a residual signal included in the first frequency range, the residual signal representing an error occurring in prediction encoding; and prediction-decoding the third channel signal subjected to prediction-encoding in the second frequency range from the first channel signal, the second channel signal.

Audio decoding device and audio decoding method

An audio coding device that uses a first-channel signal, a second-channel signal, and a plurality of channel prediction coefficients included in a code book, according to which predictive coding is performed on a third-channel signal, the first-channel signal, the second-channel signal, and the third-channel signal being included in a plurality of channels of an audio signal, the device includes, a processor; and a memory which stores a plurality of instructions, which when executed by the processor, cause the processor to execute, determining a distribution of error defined by a difference between the third-channel signal before predictive coding and the third-channel signal after predictive coding as a given curved surface according to the first-channel signal, the second-channel signal, and the third-channel signal before predictive coding; and calculating channel prediction coefficients, included in the code book.

An audio coding device includes a time frequency transform unit that, with respect to each of a plurality of channels included in an audio signal, generates a time frequency signal indicating frequency components at each time by performing a time frequency transform on a signal of the channel; a transient detection unit that detects a transient with respect to each of the plurality of channels so as to obtain a transient detection time; a transient time correction unit that, when a difference in transient detection times between an early detection channel in which the transient detection time is earliest and a late detection channel that is a channel other than the early detection channel among the plurality of channels is within a range in which the transient; a grid determination unit that, with respect to each of the plurality of channels, and a coding unit that codes.

Audio coding device, audio coding method, and computer-readable recording medium storing audio coding computer program

A decoding device to decode a main signal code obtained by encoding low-frequency components of an original signal and to output a lowband main signal for output of a main signal, includes: a processor; and a memory which stores a plurality of instructions, which when executed by the processor, cause the processor to execute, decoding auxiliary information code obtained by encoding auxiliary information, the auxiliary information being for generating, from the lowband main signal, a highband main signal corresponding to high-frequency components of the original signal; decoding residual code obtained by encoding low-frequency components of a residual signal indicating error components produced by encoding of the original signal, and thereby output a lowband residual signal; generating a highband residual signal indicating high-frequency components of the residual signal, based on the lowband residual signal output by the residual decoder and the output auxiliary information; generating an output signal.

Decoding device, encoding device, decoding method, and encoding method

A decoding device includes a decoder configured to separate a first signal obtained by performing down-mix on original signals of a plurality of channels, a residual signal representing a component of a difference between the original signals and the first signal, and spatial information representing the relationship among the original signals of the plurality of channels from an input signal which is obtained by multiplexing the first signal, the residual signal, and the spatial information and decode the separated encoded first signal, the encoded residual signal, and the encoded spatial information; a decorrelation signal generation unit configured to generate a decorrelation signal as decorrelation of the first signal decoded by the decoder; a residual signal determination unit configured to determine whether a level of the residual signal decoded by the decoder is equal to or smaller than a predetermined residual threshold value; a second-signal generation unit.

Growing community of inventors

Kawasaki, Japan

Shunsuke Takeuchi