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1996 3rd International Conference on Signal Processing(ICSP’96)

作者： Xiaoqing Yu Wanggen Wan Institute of Communication and Information Engineering Shanghai University

ISBN: (纸本)0780329120

＜正＞Based on statistical distributive law of phase information in speech signals,a new phase coding method is proposed,which is used to reduce the bit-rate of phase coding from former 45 bits per frame to present 24 bits per frame. The approach is applied to a low bit-rate speech coding system,computer simulation shows that the approach is successful,the intelligibility and naturalness of synthesized speech are satisfactory.

关键词： speech coding speech intelligibility speech synthesis phase coding speech coding statistical distributive law phase information low bit-rate computer simulation multiband excitation coding intelligibility synthesized speech

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ROBUST AND RELIABLE AUDIO WATERMARKING BASED ON DYNAMIC phase coding AND ERROR CONTROL coding

ROBUST AND RELIABLE AUDIO WATERMARKING BASED ON DYNAMIC PHAS...

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European Signal Processing Conference

作者： Nhut Minh Ngo Brian Michael Kurkoski Masashi Unoki School of Information Science Japan Advanced Institute of Science and Technology

ISBN: (纸本)9781479988518

This paper proposes an audio watermarking method based on dynamic phase coding and error control coding. The technique of quantization index modulation is employed for embedding watermarks into the phase spectrum of audio signals. Since most of the audio information is distributed in moderately low frequencies, to increase robustness, this frequency region is chosen for embedding watermarks. phase modification causes sound distortion in a manner that is proportional to the magnitude. Therefore, the amount of phase modification is adjusted according to the magnitude to balance inaudibility and robustness. Error control coding is incorporated to further increase reliability of watermark detection. The experimental results show that the watermarks could be kept inaudible in watermarked signals and robust against various attacks. Error control coding is effective in increasing watermark detection accuracy remarkably.

关键词： Audio watermarking Quantization index modulation Inaudibility Robustness Error control coding Error correction codes Watermarking Robustness Digital watermarking ERROR CONTROL phase spectrum Audio phase coding audio signals embedding

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Enhanced phase-coding method for three-dimensional shape measurement with half-period codeword

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APPLIED OPTICS 2019年第27期58卷 7359-7366页

作者： Wang, Yuwei Liu, Lu Wu, Jun Chen, Xiangcheng Wang, Yajun Anhui Agr Univ Coll Engn Hefei 230036 Anhui Peoples R China Wuhan Univ Technol Sch Automat Wuhan 430070 Hubei Peoples R China Wuhan Univ State Key Lab Informat Engn Surveying Mapping & R Wuhan 430079 Hubei Peoples R China

The phase-coding method has been widely used for 3D shape measurement, which uses sinusoidal phase-shifting patterns to recover the wrapped phase and the stair phase-coding patterns to determine the fringe order. However, due to random noises and image blurring, the fringe order is always misaligned with the wrapped phase, which will lead to fringe order errors. This paper presents an enhanced phase-coding method to address this misalignment problem by using half-period codewords, in which each codeword is aligned to the half-period of the sinusoidal patterns. Then, two complementary fringe orders with half-period dislocation can be calculated, which can effectively eliminate the fringe order errors. To extend the coding range of stair phase, this paper further develops a computational scheme based on the geometric constraint method. Simulations and experiments have been carried out, and their results confirm that the enhanced method can reliably recover the 3D shape of the measured objects. (C) 2019 Optical Society of America

关键词： 3D shape measurement image blur interference pattern phase coding codeword random noise Half Life fringe order computational scheme shape measurement

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Combined phase-Rate coding by Persistently Active Neurons as a Mechanism for Maintaining Multiple Items in Working Memory in Humans

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NEURON 2020年第2期106卷 256-+页

作者： Kaminski, Jan Brzezicka, Aneta Mamelak, Adam N. Rutishauser, Ueli Cedars Sinai Med Ctr Dept Neurosurg 8700 Beverly Blvd Los Angeles CA 90048 USA SWPS Univ Social Sci & Humanities Inst Psychol PL-03815 Warsaw Poland Cedars Sinai Med Ctr Dept Neurol 8700 Beverly Blvd Los Angeles CA 90048 USA Cedars Sinai Med Ctr Ctr Neural Sci & Med Dept Biomed Sci 8700 Beverly Blvd Los Angeles CA 90048 USA CALTECH Div Biol & Biol Engn 1200 E Calif Blvd Pasadena CA 91125 USA

Maintaining multiple items in working memory (WM) is central to human behavior. Persistently active neurons are thought to be a mechanism to maintain WMs, but it remains unclear how such activity is coordinated when multiple items are kept in memory. We show that memoranda-selective persistently active neurons in the human medial temporal lobe phase lock to ongoing slow-frequency (1-7 Hz) oscillations during WM maintenance. The properties of phase locking are dependent on memory content and load. During high memory loads, the phase of the oscillatory activity to which neurons phase lock provides information about memory content not available in the firing rate of the neurons. We provide a computational model that reveals that inhibitory-feedback-mediated competition between multiple persistently active neurons reproduces this phenomenon. This work reveals a mechanism for the active maintenance of multiple items in WM that relies on persistently active neurons whose activation is orchestrated by oscillatory activity.

关键词： working memory theta oscillations human single-neuron persistent activity local field potentials phase locking phase coding hippocampus amygdala

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Frequency and phase Mixed coding in SSVEP-Based Brain-Computer Interface

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IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING 2011年第1期58卷 200-206页

作者： Jia, Chuan Gao, Xiaorong Hong, Bo Gao, Shangkai Tsinghua Univ Dept Biomed Engn Beijing 100084 Peoples R China

Frequency coding has been the traditional method implemented in steady-state visual evoked potential (SSVEP)-based brain-computer interfaces (BCI). However, it is limited in terms of possible target numbers and, consequently, inappropriate for certain applications involving liquid crystal display (LCD) with multiple stimuli. This paper proposes an innovative coding method for SSVEP that, through a combination of frequency and phase, increases the number of targets, thus it improves the information transfer rate (ITR). With this method, a BCI system with 15 targets was developed using three stimulus frequencies, which is five times as many targets as the traditional method. Additionally, this paper defines the concept of reference phase, and decodes the EEG by means of Fourier coefficient projections onto the reference phase directions. Through the optimization of lead position, reference phase, data segment length, and harmonic components, the average ITR exceeded 60 bits/min in a simulated online test with ten subjects.

关键词： Brain-computer interfaces (BCI) frequency coding phase coding steady-state visual evoked potential (SSVEP)

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Temporal coding with Magnitude-phase Regularization for Sound Event Detection 23

Temporal Coding with Magnitude-Phase Regularization for Soun...

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Interspeech Conference

作者： Park, Sangwook Kothinti, Sandeep Elhilali, Mounya Gangneung Wonju Natl Univ Dept Elect Engn Kangnung South Korea Johns Hopkins Univ Dept Elect & Comp Engn Baltimore MD 21218 USA

Sound Event Detection (SED) is the challenge of identifying sound events into their temporal boundaries as well as sound category. With recent advances in deep learning, more effective SED techniques are investigated through the annual challenge of Detection and Classification of Acoustic Scenes and Events (DCASE). Most SED systems rely on data-driven learning where a deep neural network is trained to minimize the error between model prediction and the truth. While this framework is generally effective at identifying sound classes present in an audio recording, it results in unreliable estimates of temporal information for identifying sound boundaries. In order to heighten the temporal precision, this paper proposes a novel temporal coding of magnitude and phase for embedding vectors in an intermediate layer. This coding is reflected as a regularization term in the objective function for training the model. The regularization allows magnitude of embedding vectors to increase near event boundaries, which represent the onset and offset points. Simultaneously, each of the boundaries are distinguishable from others using phase difference between two neighboring vectors. This approach results in notable improvement in timing sensitivity compared to a baseline system tested on SED task in the context of DCASE2021 challenge.

关键词： sound event detection coherence loss time balanced focal loss phase coding

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Cortical coding of Whisking phase during Surface Whisking

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CURRENT BIOLOGY 2020年第16期30卷 3065-+页

作者： Isett, Brian R. Feldman, Daniel E. Univ Calif Berkeley Dept Mol & Cellular Biol Berkeley CA 94720 USA Univ Calif Berkeley Helen Wills Neurosci Inst Berkeley CA 94720 USA Carnegie Mellon Univ Mellon Inst 4400 Fifth Ave Pittsburgh PA 15213 USA

In rodent whisker sensation, whisker position signals, including whisking phase, are integrated with touch signals to enable spatially accurate tactile perception, but other functions of phase coding are unclear. We investigate how phase coding affects the neural coding of surface features during surface whisking. In mice performing rough-smooth discrimination, S1 units exhibit much stronger phase tuning during surface whisking than in prior studies of whisking in air. Among putative pyramidal cells, preferred phase tiles phase space, but protraction phases are strongly over-represented. Fast-spiking units are nearly all protraction tuned, This protraction bias increases the coding of stick-slip whisker events during protraction, suggesting that surface features are preferentially encoded during protraction. Correspondingly, protraction-tuned units encode rough-smooth texture better than retraction-tuned units and encode the precise spatial location of surface ridges with higher acuity. This suggests that protraction is the main information-gathering phase for high-resolution surface features, with phase coding organized to support this function.

关键词： active sensation whisking phase coding somatosensory cortex barrel cortex population code localization texture

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High-Chip-Count UWB Biphase coding for Multiuser UWB-Over-Fiber System

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JOURNAL OF LIGHTWAVE TECHNOLOGY 2009年第11期27卷 1448-1453页

作者： Dai, Yitang Yao, Jianping Univ Ottawa Microwave Photon Res Lab Sch Informat Technol & Engn Ottawa ON K1N 6N5 Canada

In this paper, we propose and demonstrate a novel technique to optically generate high-chip-count, phase-coded direct-sequence (DS) ultrawideband (UWB) signals for multiple-access UWB communications. In the proposed system, a lightwave from a laser source is phase-modulated by a Gaussian pulse train. The phase-modulated lightwave is then sent to a polarization modulator, to modulate the polarization state of the lightwave by a code pattern. The polarization-coded optical signal is then converted into a biphase-coded DS-UWB signal by a polarization-dependent frequency discriminator. The key device in the proposed system is the frequency discriminator, which is implemented using a length of polarization maintaining fiber (PMF) and a polarizer. A 127-chip, biphase-coding DS-UWB that has a data rate of 26.46 Mb/s and a chip rate of 3.36 Gb/s is experimentally generated. A multiuser UWB-over-fiber system is then proposed and a two-user system is demonstrated, in which the encoding is performed experimentally and the decoding is performed by numerically calculating the correlation between the coded UWB signal and the signature sequence. The signal of each user is well recognized. An effective two-user UWB-over-fiber system based on the DS-UWB technology is thus demonstrated.

关键词： Code-division multiple access (CDMA) direct sequence (DS) phase coding ultrawideband (UWB)

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Large aperture phase-coded diffractive lens for achromatic and 16°field-of-view imaging with high efficiency

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Chinese Physics B 2022年第7期31卷 349-360页

作者： Gu Ma Peng-Lei Zheng Zheng-Wen Hu Suo-Dong Ma Feng Xu Dong-Lin Pu Qin-Hua Wang School of Optoelectronic Science and Engineering and Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow UniversitySuzhou 215006China Key Laboratory of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Laboratory of Modern Optical Technologies of Education Ministry of China Soochow UniversitySuzhou 215006China CAS Key Laboratory of Space Precision Measurement Technology Xi’an 710119China

Diffractive lenses(DLs)can realize high-resolution imaging with light weight and compact *** DLs suffer large chromatic and off-axis aberrations,which significantly limits their practical *** many achromatic methods have been proposed,most of them are used for designing small aperture DLs,which have low diffraction *** the designing of diffractive achromatic lenses,increasing the aperture and improving the diffraction efficiency have become two of the most important design ***,a novel phase-coded diffractive lens(PCDL)for achromatic imaging with a large aperture and high efficiency is proposed and demonstrated experimentally,and it also possesses wide field-of-view(FOV)imaging at the same *** phase distribution of the conventional phase-type diffractive lens(DL)is coded with a cubic function to expand both the working bandwidth and the FOV of conventional *** proposed phase-type DL is fabricated by using the laser direct writing of grey-scale patterns for a PCDL of a diameter of 10 mm,a focal length of 100 mm,and a cubic phase coding parameter of 30π.Experimental results show that the working bandwidth and the FOV of the PCDL respectively reach 50 nm and 16°with over 8%focusing efficiency,which are in significant contrast to the counterparts of conventional DL and in good agreement with the theoretical *** work provides a novel way for implementing the achromatic,wide FOV,and high-efficiency imaging with large aperture DL.

关键词： achromatic imaging diffractive lens phase coding large aperture high efficiency

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Photonic Generation of a Dual-Band Polyphase-Coded Microwave Signal With a Tunable Frequency Multiplication Factor

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JOURNAL OF LIGHTWAVE TECHNOLOGY 2019年第19期37卷 4911-4920页

作者： Zhai, Weile Wen, Aijun Wei, Kongkun Xidian Univ State Key Lab Integrated Serv Networks Xian 710071 Shaanxi Peoples R China Xidian Univ Collaborat Innovat Ctr Informat Sensing & Underst Xian 710071 Shaanxi Peoples R China

A photonic approach to generate dual-band polyphase-coded microwave signal with a tunable frequency multiplication factor is proposed. The scheme contains a dual-polarization quadrature phase-shift-keying (DP-QPSK) modulator, a polarization modulator (PolM), and a balanced detector. When the bias voltages of the DP-QPSK modulator is properly adjusted, a double-sideband signal will be generated with one sideband along the X polarization of the PolM, with the optical carrier and the other sideband along the Y polarization. Then, the PolM is employed to modulate the optical signal with a phase-coded microwave signal. After the photoelectric balanced detection, polyphase-coded microwave signals with frequency multiplication factors of one, two, and four can be generated. In addition, the proposed scheme can simultaneously produce two phase-coded microwave signals with different carrier frequencies. The proposed system finds a potential application in dual-band radar. In the experiment, a binary- and a quaternary-phase-coded signal with 5.5, 11, and 22 GHz carrier frequencies are generated.

关键词： Dual band frequency multiplication microwave photonics microwave signal generation phase coding radar pulse compression

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