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Robust Voice Activity Detection Based on Concept of modulation transfer function in Noisy Reverberant Environments

JOURNAL OF SIGNAL PROCESSING SYSTEMS FOR SIGNAL IMAGE AND VIDEO TECHNOLOGY 2016年第2期82卷 163-173页

作者： Morita, Shota Unoki, Masashi Lu, Xugang Akagi, Masato Japan Adv Inst Sci & Technol Sch Informat Sci 1-1 Asahidai Nomi Ishikawa 9231292 Japan Natl Inst Informat & Commun Technol Universal Commun Res Inst 3-5 Hikaridai Seika Kyoto 6190289 Japan

Voice activity detection (VAD) is used to detect speech and non-speech periods from observed speech signals. It is an important front-end technique for many speech technology applications. Many VAD methods have been proposed. However most of them have been applied under clean or noisy conditions. Only a few methods have been proposed for reverberant conditions, particularly under noisy reverberant conditions. We therefore need to understand the ill effects of noise and reverberation on speech to design an accurate and robust method of VAD under noisy reverberant conditions. The ill effects of noise and reverberation for speech can be regarded as the modulation transfer function (MTF) under noisy and reverberant conditions. Therefore, our study is based on the MTF concept to reduce the ill effects of noise and reverberation on speech, and propose a robust VAD method that we obtained in this study. Noise reduction and dereverberation were first applied to the temporal power envelope of the speech signal to restore the temporal power envelope with this method. Then, power thresholding as a VAD decision was designed based on the restored temporal power envelope. A method of estimating the signal to noise ratio (SNR) was proposed to accurately estimate the SNR in the noise reduction stage. Experiments under both artificial and realistic noisy reverberant conditions were carried out to evaluate the performance of the proposed method of VAD and it was compared with conventional VAD methods. The results revealed that the proposed method significantly outperformed the conventional methods under artificial and realistic noisy reverberant conditions.

关键词： Voice activity detection modulation transfer function Noisy reverberant conditions SNR estimation Power thresholding

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Measurement of the modulation transfer function of Infrared Imaging System by Modified Slant Edge Method

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JOURNAL OF THE OPTICAL SOCIETY OF KOREA 2016年第3期20卷 381-388页

作者： Li, Hang Yang, Changxiang Shao, Jianbing Chinese Acad Sci Changchun Inst Opt Fine Mech & Phys Changchun 130033 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China

The performance of a staring infrared imaging system can be characterized based on estimating the modulation transfer function (MTF). The slant edge method is a widely used MTF estimation method, which can effectively solve the aliasing problem caused by the discrete undersampling of the infrared focal plane array. However, the traditional slant edge method has some limitations such as the low precision of the edge angle extraction and using the approximate function to fit the edge spread function (ESF), which affects the accuracy of the MTF estimation. In this paper, we propose a modified slant edge method, including an edge angle extraction method that can improve the precision of the edge angle extraction and an ESF fitting algorithm which is based on the transfer function model of the imaging system, to enhance the accuracy of the MTF estimation. This modified slant edge method presents higher estimation accuracy and better immunity to noise and edge angle than other traditional methods, which is demonstrated by the simulation and application experiments operated in our study.

关键词： modulation transfer function Slant edge method Infrared imaging system Edge angle Edge spread function

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Image quality assessment based on modulation transfer function for synthetic aperture radar systems

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JOURNAL OF APPLIED REMOTE SENSING 2016年第2期10卷 026023-1-026023-17页

作者： Lin, Xin Wang, Kaizhi Wang, Junfeng Liu, Xingzhao Shanghai Jiao Tong Univ Dept Elect Engn 800 Dongchuan Rd Shanghai 200240 Peoples R China

The performance of synthetic aperture radar (SAR) image interpretation directly depends on the image quality. However, conventional SAR image-quality indicators are measured to check whether the SAR system has maintained its performance specifications, not to assess how well the SAR image can serve image interpretation. An SAR image-quality assessment method based on the modulation transfer function (MTF) is proposed for image interpretation, which jointly reflects the resolution and the contrast of the SAR image. In addition, it describes the imaging performance of the SAR system at different spatial frequencies. Specifically, we propose a feasible MTF test field and realize it in Shanghai Jiao Tong University, Shanghai, China. Then, we give the MTF measurement procedure and utilize the MTF curve to evaluate SAR image quality. Simulation results demonstrate that the proposed MTF-based method is more accurate to assess the SAR image quality than the conventional methods. In addition, the spaceborne SAR experiments are carried out by the TerraSAR-X sensor and the experimental results are given to confirm the benefits of the proposed method. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)

关键词： synthetic aperture radar image quality assessment modulation transfer function contrast transfer function test field

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Real-Time Measurement of Ultra-High Definition Camera modulation transfer function

Real-Time Measurement of Ultra-High Definition Camera Modula...

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SMPTE Technical Conference

作者： Kenichiro Masaoka Kazuyuki Arai Kosuke Nomura Tomohiro Nakamura Yoshiro Takiguchi NHK 1-10-11 Kinuta Setagaya Tokyo 157-8510 Japan NHK 2-2-1 Jinnan Shibuya Tokyo 150-8001 Japan

The authors are solely responsible for the content of this technical presentation. The technical presentation does not necessarily reflect the Abstract. This paper presents a system capable of measuring the modulation transfer function (MTF) of a broadcast camera based on its knife-edge responses in real time. This method can be applied to multiple edges in arbitrary directions, unlike the conventional slanted-edge method in the ISO 12233 standard in which only a near-horizontal or vertical edge in a rectangular region of interest (ROI) can be analyzed. The new measurement system significantly facilitates the evaluation of the performances of the camera and lens as well as accurate focusing in an objective manner. Analysis of multidirectional edges on a starburst chart yields a contour plot of the multidirectional MTF for direct observation of the anisotropy due to not only the misalignment of the optical axis of the imaging system but also the pixel arrangement of the image sensor and image processing.

关键词： modulation transfer function Real-time measurement measurement system Cameras technical presentation Sensors (image) time measurement Optic axis Imaging systems direct observation

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Non-uniform sampling knife-edge method for camera modulation transfer function measurement 4

Non-uniform sampling knife-edge method for camera modulation...

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Conference on Optical Metrology and Inspection for Industrial Applications IV held as part of SPIE/COS Photonics Asia Conference

作者： Duan, Yaxuan Xue, Xun Chen, Yongquan Tian, Liude Zhao, Jianke Gao, Limin Chinese Acad Sci Xian Inst Opt & Precis Mech Xian Shaanxi Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China

ISBN: (数字)9781510604667

ISBN: (纸本)9781510604650;9781510604667

Traditional slanted knife-edge method experiences large errors in the camera modulation transfer function (MTF) due to tilt angle error in the knife-edge resulting in non-uniform sampling of the edge spread function. In order to resolve this problem, a non-uniform sampling knife-edge method for camera MTF measurement is proposed. By applying a simple direct calculation of the Fourier transform of the derivative for the non-uniform sampling data, the camera super-sampled MTF results are obtained. Theoretical simulations for images with and without noise under different tilt angle errors are run using the proposed method. It is demonstrated that the MTF results are insensitive to tilt angle errors. To verify the accuracy of the proposed method, an experimental setup for camera MTF measurement is established. Measurement results show that the proposed method is superior to traditional methods, and improves the universality of the slanted knife-edge method for camera MTF measurement.

关键词： Measurement modulation transfer function Cameras Numerical approximation and analysis

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modulation transfer function Consequences of Planar Dense Array Geometries in Infrared Focal Plane Arrays

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JOURNAL OF ELECTRONIC MATERIALS 2015年第9期44卷 2981-2989页

作者： Pinkie, Benjamin Wichman, Adam R. Bellotti, Enrico Boston Univ ECE Dept Boston MA 02215 USA

Finite-difference time-domain and finite element method simulations are used to evaluate two-dimensional spot-scan profiles of p-on-n double-layer planar heterostructure (DLPH) detector arrays with abrupt p-type diffusions. The modulation transfer function (MTF) is calculated from the spot-scan profiles. An asymmetric dark and photo current collection mechanism is identified and explained as a result of electric field bunching through the corners of polygonal diffusions in DLPH arrays. The MTF consequences of the asymmetric collection are studied for triangular, square, and hexagonal diffusions in square and hexagonal arrays. We show that the placement and shape of the diffusion relative to the pixel can modify the MTF by several percent. The magnitude of the effect is largest for diffusions with fewer degrees of rotational symmetry.

关键词： Infrared detectors numerical simulation modulation transfer function dense arrays HgCdTe

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NASA Technical Reports Server (Ntrs) 19840023689: Landsat-4 Thematic Mapper modulation transfer function (Mtf) Evaluation. [san Matteo Bridge and Stockton, California]

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2016年

NASA Technical Reports Server (Ntrs) 19840023689: Landsat-4 Thematic Mapper modulation transfer function (Mtf) Evaluation. [san Matteo Bridge and Stockton, California] by NASA Technical Reports Server (Ntrs); publishe... 详细信息

关键词： (mtf) (ntrs) 19840023689: aerial photography bridge california] earth resources program fast fourier transformations field of view image analysis landsat 4 modulation transfer function nasa technical reports server (ntrs) satellite imagery schowengerdt, r. [principal investigator] signal to noise ratios spatial resolution spectral bands thematic mappers (landsat)

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NASA Technical Reports Server (Ntrs) 19850007941: Landsat-4 Thematic Mapper modulation transfer function (Mft) Evaluation. [california and New Mexico]

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2016年

NASA Technical Reports Server (Ntrs) 19850007941: Landsat-4 Thematic Mapper modulation transfer function (Mft) Evaluation. [california and New Mexico] by NASA Technical Reports Server (Ntrs); published by

关键词： (mft) (ntrs) [california 19850007941: california earth resources program evaluation. image analysis landsat 4 landsat 5 modulation transfer function nasa technical reports server (ntrs) new mexico san francisco (ca) satellite imagery schowengerdt, r. [principal investigator] targets thematic mappers (landsat)

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NASA Technical Reports Server (Ntrs) 20130014799: on-Orbit Lunar modulation transfer function Measurements for the Moderate Resolution Imaging Spectroradiometer

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2016年

NASA Technical Reports Server (Ntrs) 20130014799: on-Orbit Lunar modulation transfer function Measurements for the Moderate Resolution Imaging Spectroradiometer by NASA Technical Reports Server (Ntrs); NASA Technical ... 详细信息

关键词： (ntrs) 20130014799: calibrating choi, taeyong fourier transformation function imaging imaging spectrometers imaging techniques interpolation lunar modis (radiometry) modulation transfer function nasa technical reports server (ntrs) spectroradiometers wang, zhipeng xiong, xiaoxiong

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modulation transfer function of Infrared Focal Plane Arrays 23

Modulation Transfer Function of Infrared Focal Plane Arrays

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Conference on Infrared Remote Sensing and Instrumentation XXIII

作者： Gunapala, S. D. Rafol, S. B. Ting, D. Z. Soibel, A. Hill, C. J. Khoshakhlagh, A. Liu, J. K. Mumolo, J. M. Keo, S. A. Hoeglund, L. Luong, E. M. CALTECH Jet Prop Lab Ctr Infrared Photodetectors Pasadena CA 91109 USA

ISBN: (纸本)9781628417746

modulation transfer function (MTF) is the ability of an imaging system to faithfully image a given object. The MTF of an imaging system quantifies the ability of the system to resolve or transfer spatial frequencies. In this presentation we will discuss the detail MTF measurements of 1024x1024 pixels mid-wavelength and long-wavelength quantum well infrared photodetector, and 320x256 pixels long-wavelength InAs/GaSb superlattice infrared focal plane arrays (FPAs). Long wavelength Complementary Barrier Infrared Detector (CBIRD) based on InAs/GaSb superlattice material is hybridized to recently designed and fabricated 320x256 pixel format ROIC. The n-type CBIRD was characterized in terms of performance and thermal stability. The experimentally measured NEAT of the 8.8 mu m cutoff n-CBIRD FPA was 18.6 mK with 300 K background and f/2 cold stop at 78K FPA operating temperature. The horizontal and vertical MTFs of this pixel fully delineated CBIRD FPA at Nyquist frequency are 49% and 52%, respectively.

关键词： modulation transfer function Infrared focal planes QWIP superlattice long-wave infrared

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