The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Avik Santra - One of the best experts on this subject based on the ideXlab platform.
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space time Waveform Coding for joint radar and wireless communications radcom applications
Wireless Communications and Networking Conference, 2020Co-Authors: Jan Mietzner, Avik SantraAbstract:We propose a novel space-time Waveform Coding (STWC) scheme for joint radar and wireless communications (RadCom). In particular, we consider a frequency-modulated continuous-wave (FMCW) multiple-input multiple-output (MIMO) radar for near-range to medium-range radar applications. In order to establish the required orthogonal transmit signals, up- and down-chirp FMCW Waveforms are combined with Alamouti space-time Coding across two transmit antennas. We demonstrate that, from a radar perspective, the cross-ambiguity function is improved significantly by the orthogonal Alamouti code, while the FMCW Waveforms ensure robustness in the presence of Doppler shifts. Regarding the communications part, the generic orthogonality of the Alamouti code allows us to embed random information symbols within the radar signal, enabling wireless communications in the 100 kb/s regime. To this end, we propose a suitable communications receiver algorithm for multiple antennas with corresponding maximum-ratio combining, which is able to extract the embedded information symbols while acquiring spatial diversity gains.
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WCNC - Space-Time Waveform Coding for Joint Radar and Wireless Communications (RadCom) Applications
2020 IEEE Wireless Communications and Networking Conference (WCNC), 2020Co-Authors: Jan Mietzner, Avik SantraAbstract:We propose a novel space-time Waveform Coding (STWC) scheme for joint radar and wireless communications (RadCom). In particular, we consider a frequency-modulated continuous-wave (FMCW) multiple-input multiple-output (MIMO) radar for near-range to medium-range radar applications. In order to establish the required orthogonal transmit signals, up- and down-chirp FMCW Waveforms are combined with Alamouti space-time Coding across two transmit antennas. We demonstrate that, from a radar perspective, the cross-ambiguity function is improved significantly by the orthogonal Alamouti code, while the FMCW Waveforms ensure robustness in the presence of Doppler shifts. Regarding the communications part, the generic orthogonality of the Alamouti code allows us to embed random information symbols within the radar signal, enabling wireless communications in the 100 kb/s regime. To this end, we propose a suitable communications receiver algorithm for multiple antennas with corresponding maximum-ratio combining, which is able to extract the embedded information symbols while acquiring spatial diversity gains.
Thomas Wiegand - One of the best experts on this subject based on the ideXlab platform.
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Video compression-from concepts to the H.264/AVC standard
Proceedings of the IEEE, 2005Co-Authors: Gary J Sullivan, Thomas WiegandAbstract:Over the last one and a half decades, digital video compression technologies have become an integral part of the way we create, communicate, and consume visual information. In this paper, techniques for video compression are reviewed, starting from basic concepts. The rate-distortion performance of modern video compression schemes is the result of an interaction between motion representation techniques, intra-picture prediction techniques, Waveform Coding of differences, and Waveform Coding of various refreshed regions. The paper starts with an explanation of the basic concepts of video codec design and then explains how these various features have been integrated into international standards, up to and including the most recent such standard, known as H.264/AVC.
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3-D IMAGING AND COMPRESSION – SYNTHETIC HYBRID OR NATURAL FIT?
2002Co-Authors: Bernd Girod, Peter Eisert, M. Magnor, Eckehard Steinbach, Thomas WiegandAbstract:International Workshop on Synthetic-Natural Hybrid Coding and Three Dimensional Imaging IWSNHC3DI’99, Santorini, Greece, September 1999. This paper highlights recent advances in image compression aided by 3-D geometry information. As two examples, we present a modelaided video coder for efficient compression of head-and-shoulder scenes and a geometry-aided coder for 4-D light fields for image-based rendering. Both examples illustrate that an explicit representation of 3-D geometry is advantageous if many views of the same 3-D object or scene have to be encoded. Waveform-Coding and 3-D model-based Coding can be combined in a ratedistortion framework, such that the generality of Waveform Coding and the efficiency of 3-D models are available where needed.
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State-of-the-Art Video Transmission
Multi-Frame Motion-Compensated Prediction for Video Transmission, 2001Co-Authors: Thomas Wiegand, Bernd GirodAbstract:This book discusses ideas to improve video transmission systems via enhancing the rate-distortion efficiency of the video compression scheme. The rate-distortion efficiency of today’s video compression designs is based on a sophisticated interaction between various motion representation possibilities, Waveform Coding of differences, and Waveform Coding of various refreshed regions. Modern video codecs achieve good compression results by efficiently combining the various technical features. The most successful and widely used designs today are called hybrid video codecs. The naming of these codecs is due to their construction as a hybrid of MCP and picture Coding techniques. The ITU-T Recommendation H.263 is an example for a hybrid video codec specifying a highly optimized video syntax.
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ICIP (2) - 3-D image models and compression: synthetic hybrid or natural fit?
Proceedings 1999 International Conference on Image Processing (Cat. 99CH36348), 1999Co-Authors: Bernd Girod, Peter Eisert, M. Magnor, Eckehard Steinbach, Thomas WiegandAbstract:This paper highlights recent advances in image compression aided by 3-D geometry information. As two examples, we present a model-aided video coder for efficient compression of head-and-shoulder scenes and a geometry-aided coder for 4-D light fields for image-based rendering. Both examples illustrate that an explicit representation of 3-D geometry is advantageous if many views of the same 3-D object or scene have to be encoded. Waveform-Coding and 3-D model-based Coding can be combined in a rate-distortion framework, such that the generality of Waveform Coding and the efficiency of 3-D models are available where needed.
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Rate-distortion optimization for: Video compression
IEEE Signal Processing Magazine, 1998Co-Authors: Gary J Sullivan, Thomas WiegandAbstract:The rate-distortion efficiency of video compression schemes is based on a sophisticated interaction between various motion representation possibilities, Waveform Coding of differences, and Waveform Coding of various refreshed regions. Hence, a key problem in high-compression video Coding is the operational control of the encoder. This problem is compounded by the widely varying content and motion found in typical video sequences, necessitating the selection between different representation possibilities with varying rate-distortion efficiency. This article addresses the problem of video encoder optimization and discusses its consequences on the compression architecture of the overall Coding system. Based on the well-known hybrid video Coding structure, Lagrangian optimization techniques are presented that try to answer the question: what part of the video signal should be coded using what method and parameter settings?
Jan Mietzner - One of the best experts on this subject based on the ideXlab platform.
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space time Waveform Coding for joint radar and wireless communications radcom applications
Wireless Communications and Networking Conference, 2020Co-Authors: Jan Mietzner, Avik SantraAbstract:We propose a novel space-time Waveform Coding (STWC) scheme for joint radar and wireless communications (RadCom). In particular, we consider a frequency-modulated continuous-wave (FMCW) multiple-input multiple-output (MIMO) radar for near-range to medium-range radar applications. In order to establish the required orthogonal transmit signals, up- and down-chirp FMCW Waveforms are combined with Alamouti space-time Coding across two transmit antennas. We demonstrate that, from a radar perspective, the cross-ambiguity function is improved significantly by the orthogonal Alamouti code, while the FMCW Waveforms ensure robustness in the presence of Doppler shifts. Regarding the communications part, the generic orthogonality of the Alamouti code allows us to embed random information symbols within the radar signal, enabling wireless communications in the 100 kb/s regime. To this end, we propose a suitable communications receiver algorithm for multiple antennas with corresponding maximum-ratio combining, which is able to extract the embedded information symbols while acquiring spatial diversity gains.
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WCNC - Space-Time Waveform Coding for Joint Radar and Wireless Communications (RadCom) Applications
2020 IEEE Wireless Communications and Networking Conference (WCNC), 2020Co-Authors: Jan Mietzner, Avik SantraAbstract:We propose a novel space-time Waveform Coding (STWC) scheme for joint radar and wireless communications (RadCom). In particular, we consider a frequency-modulated continuous-wave (FMCW) multiple-input multiple-output (MIMO) radar for near-range to medium-range radar applications. In order to establish the required orthogonal transmit signals, up- and down-chirp FMCW Waveforms are combined with Alamouti space-time Coding across two transmit antennas. We demonstrate that, from a radar perspective, the cross-ambiguity function is improved significantly by the orthogonal Alamouti code, while the FMCW Waveforms ensure robustness in the presence of Doppler shifts. Regarding the communications part, the generic orthogonality of the Alamouti code allows us to embed random information symbols within the radar signal, enabling wireless communications in the 100 kb/s regime. To this end, we propose a suitable communications receiver algorithm for multiple antennas with corresponding maximum-ratio combining, which is able to extract the embedded information symbols while acquiring spatial diversity gains.
Myung-jin Bae - One of the best experts on this subject based on the ideXlab platform.
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ICTC - A new hybrid non-uniform Coding with low bit rates for sound signal in near field communication
2013 International Conference on ICT Convergence (ICTC), 2013Co-Authors: Seonggeon Bae, Myung-sook Kim, Myung-jin BaeAbstract:In speech or audio processing, Coding may be define as a digital representation of signal that provides efficient storage, transmission, recovery, and perceptually faithful reconstruction of the original signal. In the Coding methods, the Waveform Coding method can maintain the high quality and intelligibility, but the major drawback of this method is large amount of data required. Therefore, we proposed a Waveform Coding method using the non-uniform sampling and variables low pass filter of speech or audio signals. Simulation results show that this algorithm is robust in noisy environments.
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FGIT-EL/DTA/UNESST - A Study on a New Non-uniform Speech Coding Using the Components of Separated by Harmonics and Formants Frequencies
Communications in Computer and Information Science, 2012Co-Authors: Seonggeon Bae, Myung-jin BaeAbstract:In speech processing, Coding may be define as a digital representation of speech sound that provides efficient storage, transmission, recovery, and perceptually faithful reconstruction of the original speech. In the Coding methods, the Waveform Coding method can maintain the high quality and personality, but the major drawback to this method is large amount of data required. Therefore, we suggest a Waveform Coding method using the nonuniform sampling and separated bandwidth of speech signals. Results show that this algorithm is robust in noisy environments, and we can get the average compression ratios of 5.67 and the gains of 3dB in our algorithm for original speech.
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On a Pitch Alteration for Speech Synthesis Systems
Wireless Personal Communications, 2009Co-Authors: Jongkuk Kim, Hernsoo Hahn, Uei-joong Yoon, Myung-jin BaeAbstract:Speech synthesis can be classified into Waveform Coding, source Coding, or hybrid Coding by the synthesis method. Among these, Waveform Coding is especially suitable for high-quality speech synthesis. However, synthesis techniques using syllable or phoneme unit is not desirable since it fails to separate the excitation and the formant part to handle speech. Therefore, there is a need for a pitch alteration method to apply in synthesis using Waveform Coding. This study proposes a pitch alteration method that uses spectrum scaling after flattening the spectra by a sub-band linear approximation to minimize the spectrum distortion. A comparison with LPC (Linear Predictive Coding), Cepstrum and lifter function is presented to show the better performance of the proposed method. Estimation method seeks each of the distributions of the flattened signal and measures the degree of the flattened spectrum Signal, which is normalized, so the highest point amounts to zero, and the distribution of the signal, whose average is zero, is calculated. The results are presented by the spectrum distortion rate to estimate the performance of the proposed method. The average spectrum distortion rate kept below the average 2.12%, showing the proposed method’s superiority in comparison with the other existing approaches.
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OX A SPEECH SJ'KTHESIS TECHNIQCE IVITH HIGH QUALITY BY THE PITCH ALTER.4TIOS OF SPEECH W-4L'EFORM
1996Co-Authors: Dongsung Kim, Myung-jin Bae, Ieem Joon-seokAbstract:The Waveform Coding techniques are concerned with simply preserving the Waveform shape of speech signal through a redundancy reduction process. In the case of speech synthesis, the Waveform Coding with high quality are mainly used to the synthesis by analysis. However, since the parameters of this Coding are not classified into either excitation or vocal tract parameters, it is difficult to applying the Waveform Coding to the synthesis by rule. In order to applying the Waveform Coding to the synthesis by rule, the pitch alteration technique is required in prosody control. In this paper, we propose a new pitch alteration method that can change the pitch period in Waveform Coding by scaling the time-axis and compensating the spectrum. This is a kind of timefrequency domain methods where the phase components of the Waveform are preserved with a little spectrum distortion of 2.5
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On a Pitch Alteration Method by Time-axis Scaling Compensated with the Spectrum for High Quality Speech Synthesis
The Journal of the Acoustical Society of Korea, 1995Co-Authors: Myung-jin Bae, Won Cheol LeeAbstract:The Waveform Coding technique has concerned with simply preserving the Waveform shape of speech signal through a redundancy reduction process. In the case of speech synthesis, the Waveform Coding with high sound quality is mainly used to the synthesis by analysis. However, since the parameters of this Coding are not classified into either excitation or vocal tract parameters, it is difficult to applying the Waveform Coding to the synthesis by rule. In order to apply the Waveform Coding to the synthesis by rule, the pitch alteration technique is required in prosody control. In this paper, we propose a new pitch alteration method that can change the pitch period in Waveform Coding by scaling the time-axis and compensating the spectrum. This is relevant to the time-frequency domain method were the phase components of the Waveform is preserved with a little spectrum distortion of 2.5 % and less for 50% pitch change.
Hiroshi Harashima - One of the best experts on this subject based on the ideXlab platform.
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model based Waveform hybrid Coding for videotelephone images
International Conference on Acoustics Speech and Signal Processing, 1991Co-Authors: Y. Nakaya, Y.c. Chuah, Hiroshi HarashimaAbstract:An image Coding method that combines model-based Coding with conventional Waveform Coding is presented. Despite its potential to realize image communication at very low rates, model-based Coding still has many glitches that need to be solved before any practical use. The major problems are the difficulty in modeling unknown objects and the presence of analysis errors. To cope with these difficulties, Waveform Coding is incorporated into model-based Coding. The incorporated Waveform coder can code unmodeled objects and cancel errors of the analysis system. A general model of model-based/Waveform hybrid Coding is discussed. Preliminary simulation results of a model-based/MC-DCT hybrid Coding system show that this hybrid Coding method is effective at very low transmission rates, such as 16 kb/s. >
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ICASSP - Model-based/Waveform hybrid Coding for videotelephone images
[Proceedings] ICASSP 91: 1991 International Conference on Acoustics Speech and Signal Processing, 1991Co-Authors: Y. Nakaya, Y.c. Chuah, Hiroshi HarashimaAbstract:An image Coding method that combines model-based Coding with conventional Waveform Coding is presented. Despite its potential to realize image communication at very low rates, model-based Coding still has many glitches that need to be solved before any practical use. The major problems are the difficulty in modeling unknown objects and the presence of analysis errors. To cope with these difficulties, Waveform Coding is incorporated into model-based Coding. The incorporated Waveform coder can code unmodeled objects and cancel errors of the analysis system. A general model of model-based/Waveform hybrid Coding is discussed. Preliminary simulation results of a model-based/MC-DCT hybrid Coding system show that this hybrid Coding method is effective at very low transmission rates, such as 16 kb/s. >
