Abstract:
서로 다른 CELP 방식의 음성 코덱 간의 상호부호화 장치 및 그 방법이 개시된다. 본 발명에 따른 서로 다른 CELP 방식의 음성 코덱 간의 상호부호화 장치는 서로 다른 포맷을 갖는 입력 CELP 코덱과 출력 CELP 코덱 사이에서, 입력 CELP 코덱의 포맷을 출력 CELP 코덱의 포맷으로 변환하는 본 발명에 따른 상호부호화 장치는 입력 CELP 코덱 포맷으로 부호화된 비트스트림를 음성 신호로 변환하는 입력 CELP 코덱의 복호화 처리부, 기준필터를 기준으로, 스펙트럼 왜곡이 최소가 되는 최적의 가중치를 적용하여 계산되는 필터 특성으로 입력 CELP 코덱의 복호화 처리부에서 복호화된 음성신호를 필터 처리하는 상호부호화 필터, 다수의 가중치로 이루어진 가중치 세트로부터 상호부호화 필터의 스펙트럼 왜곡을 최소화하는 최적의 가중치를 추출하여 상호부호화 필터로 제공하는 상호부호화 필터 설계부 및 상호부호화 필터에서 필터 처리된 음성신호를 부호화하여 출력 CELP 코덱 포맷의 비트스트림를 생성하는 출력 CELP 코덱의 부호화 처리부를 포함하는 것을 특징으로 하고, 하나의 상호부호화 필터를 이용하여 종래의 후-필터 및 지각가중필터를 대신함으로써, 상호부호화기의 연산량을 감소시키면서도 수신단에서 복호화된 음성의 음질을 향상시킬 수 있다.
Abstract:
상호부호화기에서 개회로 피치 추정 방법 및 그 장치가 개시된다. 서로 다른 CELP 방식의 음성 코덱 간의 상호부호화를 위한 상호부호화기에서 본 발명에 따른 개회로 피치 추정 방법은, 입력 CELP 코덱 포맷으로 부호화된 비트스트림를 음성 신호로 복호화하고, 복호화된 음성신호의 각 부-프레임에 대한 폐-루프 피치를 추출하는 (a)단계, 복호화된 음성 신호를 사람의 청각기관 특성을 고려한 지각가중필터 처리를 하는 (b)단계, 복호화된 폐-루프 피치와, 이전 프레임의 마지막 부-프레임에 대한 폐-루프 피치 또는 동일 프레임에 대한 이전 개-루프 피치를 이용하여 결정된 개-루프 피치 검색 범위에서 지각가중필터링된 음성신호의 개-루프 피치를 검색하는 (c)단계 및 검색된 개-루프 피치를 이용하여 결정된 폐-루프 피치 검색 범위에서 지각가중 필터링된 음성신호의 폐-루프 피치를 검색하고, 검색된 결과를 출력 CELP 코덱 포맷의 피치 지연값으로서 생성하는 (d)단계를 포함하는 것을 특징으로 하며, 기존 재-검색 방식보다 음질 저하를 줄일 수 있으며, 계산량 감소 효과를 얻을 수 있다.
Abstract:
PURPOSE: A transceiver for encoding and decoding voice using an additional bit assignment method is provided to offer a high-quality voice service by assigning only additional bits admitted in a system using a voice encoder used in an old voice processing system. CONSTITUTION: A standard voice encoding unit(102) classifies an inputted voice signal into spectrum information indicating a vocal tract transfer function and an excitation signal component, and models and quantizes spectrum information and the excitation signal component. The standard voice encoding unit(102) performs the standard encoding of the quantized signal, and generates a standard-encoded bit series. A quality improvement encoding unit(103) obtains an error between a signal in which spectrum information is not quantized and a signal in which spectrum information is quantized by the standard voice encoding unit(102). The quality improvement encoding unit(103) obtains an error between a signal in which the excitation signal component is not quantized and a signal in which the excitation signal component is quantized. The quality improvement encoding unit(103) additionally quantizes the obtained errors, and generates an encoded bit series. A multiplexing unit(104) multiplexes the bit series obtained in the standard voice encoding unit(102) and the quality improvement encoding unit(103), and transmits the multiplexed bit series.
Abstract:
본 발명은 화자인식시스템의 화자 특징벡터 생성방법 및 시스템에 관한 것으로서, 입력된 화자 음성신호에서 특징벡터를 추출하여 화자모델링 훈련 및 화자인식을 수행하는 화자인식시스템에 있어서, 입력된 화자음성신호의 피치간격을 측정하고 소정의 피치구간 음성신호를 추출하는 피치구간 음성추출수단, 피치구간음성추출수단에서 추출된 음성신호의 특징벡터를 생성하는 특징벡터생성수단을 포함하여 이루어진 것을 특징으로 한다.
Abstract:
The present invention relates to a transmitter and a receiver for speech coding and decoding by using an additional bit allocation method. The transmitter and the receiver according to the present invention realize a voice communication service of high quality by using additional bits permitted in system requirements while using a conventional speech coder as it is. In addition, the transmitter and the receiver according to the present invention have an advantage in that they enable insertion of additional quantization blocks while not changing the structure of the conventional standard speech coder, since they allocate additional bits by applying a multi-stage quantization procedure not in a speech signal domain but in a parameter domain.
Abstract:
PURPOSE: An apparatus and a method for transcoding data between speech codecs having different CELP(Code Excited Linear Prediction) types are provided to reduce quantity of calculation and offer speech with high quality by utilizing one transcoding filter instead of a post-processing filter and a perception weighting filter. CONSTITUTION: A decoding process part(321) converts a bitstream with an input CELP codec format into a speech signal, wherein the bitstream is formed by coding an input speech signal. A transcoding filter(323) filters the decoded speech signal by filter characteristics calculated by adopting an optimal weighting value for minimum spectrum distortion. A transcoding filter design part(322) extracts the optimal weighting value from a weighting value set comprised of a plurality of weighting value pairs. A coding process part(324) codes the speech signal processed by the transcoding filter and thereby generates a bitstream of an output CELP codec format.
Abstract:
PURPOSE: A wideband voice encoder, a method therefor, a wideband decoder and a method therefor are provided to offer excellent voice quality in a voice interval which is not processed by an algebraical codebook by performing multi-stage fixed codebook retrieval. CONSTITUTION: A voice characteristic classifying unit(105) classifies the characteristic of a voice corresponding to a current frame using an open-loop pitch value of a recognition weight filtered signal of a wideband voice signal and a linear prediction factor by a statistical method. An adaptive codebook retrieving unit(106) retrieves a pitch delay value near the open-loop pitch value, calculates a pitch gain value, and generates an adaptive codebook contribution signal. The adaptive codebook retrieving unit outputs difference between the generated adaptive codebook contribution signal and the recognition weight filtered signal as a primary fixed codebook target signal. A primary fixed codebook retrieving unit(107) obtains a primary fixed codebook index and a primary fixed codebook gain value, generates a primary fixed codebook contribution signal corresponding to the obtained primary fixed codebook index. The primary fixed codebook retrieving unit outputs different between the generated primary fixed codebook contribution signal and the primary fixed codebook target signal as a secondary codebook target signal. A secondary fixed codebook retrieving unit(108) has at least two or more fixed codebooks according to voice characteristics, selects one secondary fixed codebook according to voice characteristic information, and retrieves secondary fixed codebook indexes and secondary fixed codebook gain values according to the voice characteristics. A parameter multiplexing unit(110) multiplexes voice characteristic information, the pitch delay value, the pitch gain value, the primary fixed codebook index, the primary fixed codebook gain value, the secondary fixed codebook indexes and the secondary fixed codebook gain values, generates a bit stream, and transmits the bit stream to an external voice decoding terminal.
Abstract:
PURPOSE: An apparatus and a method for transmitting/receiving a wideband voice signal are provided to offer high sound quality 16 kHz sampled wideband voice signal and compatibility with an existing system. CONSTITUTION: A analyzing/filtering unit(301) receives a digital voice signal and outputs a low band voice signal having a bandwidth of 0-4 kHz of 8 kHz sampling period. A low band standard coding unit(302) receives the low band voice signal, codes it and outputs a coded low band standard signal. A low band additional coding unit(304) receives a difference between a filtered low band voice signal and a composite signal that has been decoded by a low band standard decoding unit(303) and codes them to generate a low band additional signal. An enhancement residual band coding unit(306) up-samples a composite signal obtained by combining signals outputted from the low band standard decoding unit(303) and the low band additional decoding unit(305), obtains a difference between the up-sampled signal and a voice signal inputted to the analyzing/filtering unit(301), and generates an enhancement residual band signal.