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2008 IEEE International Geoscience and Remote Sensing Symposium - Proceedings

作者： Morstad, Daniel L. Helder, Dennis L. Image Processing Laboratory South Dakota State University SD 57007 United States Electrical Engineering and Computer Science Department South Dakota State University SD 57007 United States

ISBN: (纸本)9781424428083

Over the past several years, pseudo-invariant sites for trending the radiometric gain of multispectral satellite imaging systems has proven to be very useful and accurate. For example, the lifetime calibration of the Landsat 5 Thematic Mapper (TM) was recently updated based in large part upon this approach. This effort reduced the error in the gain estimate from roughly 13 percent to less than 5 percent and integrated a variety of absolute calibration estimates for the sensor [1]. Typically, pseudo-invariant sites are located in arid regions where very little temporal and spatial change occurs over long periods of time and significant extent. Sites in the Sahara desert are especially attractive. However, drawbacks of this approach are that the sites are relatively unacceptable and, for some instruments, only limited numbers of data sets are available. As a result, it would be helpful to use sites that are observed often, such as locations in North America, so that the technique could be applied to more sensors both historically and in the future. The drawback to these sites is that they are typically of much smaller extent and, therefore, are more difficult to use from a geometric perspective. Recent work has shown that small pseudo-invariant sites, if carefully chosen, can also be used for accurate trending of satellite instruments. This paper will illustrate an approach that suggests the calibration site commonly known as Sonoran Desert can be used to observe the characteristic calibration curve of Landsat 5 TM. Because of the significant number of observations of this site, and other similar sites in North America, there is good potential to extend this technique to additional multispectral instruments for enhanced long term monitoring of radiometric gain. © 2008 IEEE.

关键词： Landsat

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Fast Blind Adaptive Channel Shortening Using Signal Subspace

Fast Blind Adaptive Channel Shortening Using Signal Subspace

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IEEE Conference on Vehicular Technology (VTC)

作者： Mahdi Karami Ali Olfat Signal Processing & Communication Systems Laboratory Department of Electrical and Computer Engineering University of Tehran Iran

In cyclic-prefixed communication systems, if the delay spread of the channel is longer than the cyclic prefix (CP) a channel-shortening equalizer (CSE) can be used to restore the desired operation of such systems. Since in time-varying environment we are interested in fast adaptive equalizer with tracking capability, the aim of this paper is to propose RLS-type algorithm for channel shortening. In this paper, we first propose an RLS-type algorithm to estimate the eigenvector corresponding to the smallest eigenvalue of a matrix and based on this algorithm we develop an RLS-type blind channel shortener. We also, based on PAST algorithm, propose an RLS-type update rule to shorten the channel under MMSE criterion. Simulations show the speed advantage of the proposed algorithms.

关键词： Signal processing algorithms OFDM Nonlinear filters Equalizers Eigenvalues and eigenfunctions Finite impulse response filter Signal processing Adaptive signal processing Laboratories Delay systems

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A pyramid-based block of skewers for pixel purity index for endmember extraction in hyperspectral imagery

A pyramid-based block of skewers for pixel purity index for ...

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作者： Chang, Chein-I Hsueh, Mingkai Liu, Weimin Wu, Chao-Cheng Chaudhry, Farzeen Solyar, Gregory Plaza, Antonio Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore County Baltimore MD 21250 United States Computer Science Department University of Extremadura Avda. de la Universidad s/n 10.071 Caceres Spain

Pixel Purity Index (PPI) has been widely used for endmember extraction. Recently, an approach using blocks of skewers was proposed by Theiler et al., called blocks of skewers (BOS) method, to improve computation of the PPI. It utilizes a block of skewers to reduce number of calculations of dot products operated by the PPI on each skewers with all data sample vectors. Unfortunately, the BOS method also suffers from the same drawbacks that the PPI does in terms of several parameters which are needed to be determined a priori. Besides, it also has an additional parameter, block size, B needed to be determined where no guideline is provided of how to select this parameter. In this paper, the BOS method is also investigated. Most importantly, a new pyramid-based block design for the BOS method is also introduced as opposed to the cube-based block designed used by Theiler et al.'s BOS. One major advantage of our proposed pyramid-based BOS over Theiler et al.'s cube-design BOS is the hardware design for Field Programmable Gate Arrays (FPGAs) implementation. © 2008 World Scientific Publishing Company.

关键词： Pixels

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Joint angle tracking with inertial sensors

Joint angle tracking with inertial sensors

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： Mahmoud El-Gohary Sean Pearson James McNames Department of Electrical and Computer Engineering Biomedical Signal Processing Laboratory Portland State University Portland OR USA

Many wearable inertial systems have been used to continuously track human movement in and outside of a laboratory. The number of sensors and the complexity of the algorithms used to measure position and orientation vary according to the clinical application. To calculate changes in orientation, researchers often integrate the angular velocity. However, a relatively small error in measured angular velocity leads to large integration errors. This restricts the time of accurate measurement to a few minutes. We have combined kinematic models designed for control of robotic arms with state space methods to directly and continuously estimate the joint angles from inertial sensors. These algorithms can be applied to any combination of sensors, can easily handle malfunctions or the loss of some sensor inputs, and can be used in either a real-time or an off-line processing mode with higher accuracy.

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Speech enhancement using a Kalman-based normalized LMS algorithm

Speech enhancement using a Kalman-based normalized LMS algor...

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International Symposium on Telecommunications, IST

作者： A. Mahmoodzadeh H. R. Abutalebi H. Agahi Signal Processing Research Laboratory Electrical Engineering Department Yazd University Yazd Iran Electrical and Computer Engineering Department University of Tehran Tehran Iran

This paper deals with the problem of Adaptive Noise Cancellation (ANC) for the speech signal corrupted with an additive white Gaussian noise. After explaining the least Mean Square (LMS)-based adaptive filter and Kalman filter, we examine the hybrid Kalman-based LMS (KLMS) technique for adaptation of the ANC. The proposed technique suggests a way to normalize LMS algorithm using Kalman filter. Our simulation shows that the KLMS method converges faster and is more stable compared to the LMS and its Normalized version, NLMS.

关键词： Artificial neural networks Least squares approximation Kalman filters Speech Speech enhancement Adaptive filters Noise

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Three-dimensional ISAR imaging based on antenna array

Three-dimensional ISAR imaging based on antenna array

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作者： Ma, Changzheng Yeo, Tat Soon Zhang, Qun Tan, Hwee Siang Wang, Jun IEEE School of Electric and Information Engineering Zhongyuan University of Technology Zhengzhou 450007 China Department of Electrical and Computer Engineering National University of Singapore Singapore 117576 Singapore Institute of Telecommunication Engineering Air Force Engineering University Xi'an 710071 China National Key Laboratory of Radar Signal Processing Xidian University Shaanxi 710071 China

In this paper, a 3-D inverse synthetic aperture radar (ISAR) imaging method based on an antenna array configuration is proposed. The performance of conventional interferometric ISAR imaging system using three antennas is poor, as the positions of scatterers, which have the same range-Doppler value and projected onto the ISAR plane as a synthesis scatterer, cannot be correctly estimated. However, by using two antenna arrays perpendicular to each other, the system's ability to separate these scatterers can be improved. The criterion for the selection of a range unit that contains an isolated scatterer in the 2-D array domain for doing motion compensation is discussed. If there is no range unit which contains only an isolated scatterer, then radial and cross-range motion compensation has to be carried out by motion parameter estimation. Two cross-range motion parameters measurement algorithms, one based on array processing of the range profile and another based on correlation of ISAR images of different antennas, are proposed. The coordinates registration problem for the scatterers of a synthesis scatterer is also discussed. Simulation results have shown the effectiveness of the proposed methods. © 2008 IEEE.

关键词： Synthetic aperture radar

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Fundamental Uncertainty Rotationally Symmetric and Anamorphic Laser Triangulation

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电子学报(英文版) 2008年第1期17卷 8-11页

作者： WANG Lei GAO Jun WANG Xiaojia Johannes Eckstein Peter Ott Laboratory of Image Information Processing School of Computer and Information Hefei University of Technology Hefei 230009 China Optical Engineering Laboratory Heilbronn University Heilbronn 74081 Germany Department of Mechanical and Electrical Engineering Xiamen University Xiamen 361005 China

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Use of Pseudo-Invariant Sites for Long-Term Sensor Calibration

Use of Pseudo-Invariant Sites for Long-Term Sensor Calibrati...

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IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： Daniel L. Morstad Dennis L. Helder Image Processing Laboratory South Dakota State University SD USA Electrical Engineering and Computer Science Department South Dakota State University SD USA

Over the past several years, pseudo-invariant sites for trending the radiometric gain of multispectral satellite imaging systems has proven to be very useful and accurate. For example, the lifetime calibration of the Landsat 5 Thematic Mapper (TM) was recently updated based in large part upon this approach. This effort reduced the error in the gain estimate from roughly 13 percent to less than 5 percent and integrated a variety of absolute calibration estimates for the sensor. Typically, pseudo-invariant sites are located in arid regions where very little temporal and spatial change occurs over long periods of time and significant extent. Sites in the Sahara desert are especially attractive. However, drawbacks of this approach are that the sites are relatively unacceptable and, for some instruments, only limited numbers of data sets are available. As a result, it would be helpful to use sites that are observed often, such as locations in North America, so that the technique could be applied to more sensors both historically and in the future. The drawback to these sites is that they are typically of much smaller extent and, therefore, are more difficult to use from a geometric perspective. Recent work has shown that small pseudo-invariant sites, if carefully chosen, can also be used for accurate trending of satellite instruments. This paper will illustrate an approach that suggests the calibration site commonly known as Sonoran Desert can be used to observe the characteristic calibration curve of Landsat 5 TM. Because of the significant number of observations of this site, and other similar sites in North America, there is good potential to extend this technique to additional multispectral instruments for enhanced long term monitoring of radiometric gain.

关键词： Calibration Remote sensing Radiometry Satellite broadcasting Instruments North America Remote monitoring Uncertainty Layout Sun

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Radiometric Calibration of Reflective Bands of Landsat 4 Thematic Mapper using Pseudo-Invariant Site Technique

Radiometric Calibration of Reflective Bands of Landsat 4 The...

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IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： Rimy Malla Dennis L. Helder Image Processing Laboratory South Dakota State University SD USA Electrical Engineering and Computer Science Department South Dakota State University SD USA

Historically, for purposes of calibration, the Landsat 4 Thematic Mapper (TM) sensor has relied upon prelaunch calibration data, internal calibration data and very limited post-launch data. Landsat 4 additionally has used Landsat 5 TM cross-calibration data. The availability of one more independent source, commonly called pseudo-invariant sites, can be used to improve the calibration of the sensor. Pseudo-invariant sites are mainly well characterized desert sites exhibiting the properties of high reflectance, high spatial and spectral uniformity, temporal stability and are nearly Lambertian to decrease BRDF and shadow effects. The successful update of the calibration of the Landsat 5 TM sensor using the pseudo-invariant site approach suggested using this approach to calibrate the Landsat 4 TM sensor. The pseudo-invariant sites selected to characterize the Landsat 4 TM sensor are Middle East sites at Path 166, Row 39 and Path 166, Row 40. Previously, calibration attempts have been primarily based only on the internal calibrator (IC) and prelaunch data. The Landsat 5 internal calibrator was found to be unreliable approximately three years after launch. The Landsat 4 IC data also become questionable especially knowing that the internal calibrators for both the instruments were essentially identical. Thus, it is necessary to characterize the system with another independent and reliable source-in this case pseudo-invariant sites. Unfortunately, due to the unavailability of an adequate number of scenes at the site used for Landsat 5, the Middle East site of Path 166, Row 39 and Path 166, Row 40 were selected. A large drawback of these sites is that they are the locations of the First Gulf War in 1991. This negates the assumption that the surface and atmosphere did not change during the study period. To account for the change, radiometric correction was done using the known Landsat 5 gain signature. A correction factor, which is the ratio of the averages of Landsat 5 pre-g

关键词： Radiometry Calibration Satellites Remote sensing Sensor phenomena and characterization Integrated circuit modeling Reflectivity Stability Instruments Layout

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A PYRAMID-BASED BLOCK OF SKEWERS FOR PIXEL PURITY INDEX FOR ENDMEMBER EXTRACTION IN HYPERSPECTRAL IMAGERY

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International Journal of High Speed Electronics and Systems 2008年第2期18卷 469-482页

作者： CHEIN-I CHANG MINGKAI HSUEH WEIMIN LIU CHAO-CHENG WU FARZEEN CHAUDHRY GREGORY SOLYAR ANTONIO PLAZA Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore County Baltimore MD 21250 USA Computer Science Department University of Extremadura Avda. de la Universidad s/n 10.071 Caceres Spain

Pixel Purity Index (PPI) has been widely used for endmember extraction. Recently, an approach using blocks of skewers was proposed by Theiler et al., called blocks of skewers (BOS) method, to improve computation of the PPI. It utilizes a block of skewers to reduce number of calculations of dot products operated by the PPI on each skewers with all data sample vectors. Unfortunately, the BOS method also suffers from the same drawbacks that the PPI does in terms of several parameters which are needed to be determined a priori . Besides, it also has an additional parameter, block size, B needed to be determined where no guideline is provided of how to select this parameter. In this paper, the BOS method is also investigated. Most importantly, a new pyramid-based block design for the BOS method is also introduced as opposed to the cube-based block designed used by Theiler et al.'s BOS. One major advantage of our proposed pyramid-based BOS over Theiler et al.'s cube-design BOS is the hardware design for Field Programmable Gate Arrays (FPGAs) implementation.

关键词： Blocks of skewers (BOS) method Field Programmable Gate Arrays (FPGAs) Pixel purity index (PPI)

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