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signal and data processing of small targets 1990

作者： Drummond, O.E. Blackman, S.S. Peirisor, G.C. Hughes Aircraft Co. 2141 E. Rosecrans Boulevard El SegundoCA90245 United States

ISBN: (纸本)9780819403568

This paper develops a group tracking algorithm for the tracking of clusters of closely spaced targets as viewed by passive sensors. This problem is complex because the size and shape of the observed cluster will differ from sensor to sensor. Since a passive sensor provides projection of the objects, possible sensors in different locations will provide different projections of the 3-dimensional (3-D) shape of a cluster. Furthermore, the number of resolved objects in a cluster can vary as closely spaced targets may appear to a sensor as a single extended object. In order to track the target clusters with multiple sensois, a method is needed to characterize the size, shape and location of each cluster. The method described in this paper models the target cluster in 3-D as an effipsoid with the projection in 2-D being an effipse. The centroid and parameteis of the ethpsoid are tracked over time using measurements from widely spaced passive sensors. The filtering methods are described and performance is presented based upon tracking simulations. Application of this method to tracking extended objects with multiple sensors is also discussed. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.

关键词： data handling

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Neural network implementation of plot/track association

Neural network implementation of plot/track association

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signal and data processing of small targets 1990

作者： Smith, William F. Ekchian, Leon K. Johnson, David D. Litton Data Systems 8000 Woodley Ave Van NuysCA91409 United States

ISBN: (纸本)9780819403568

Plot/track association consists of assigning radar plots to predicted track positions and is an important feature of all track while scan systems. We demonstrate the feasibility of applying neural network technology to the plot/track association problem in such a way as to achieve good global solutions. The plot/track association problem can be structured in a basic framework very similar to that of the classic Travelling Salesman Problem (TSP). Hopfield organization networks have been applied to the TSP by various researchers, but with varying degrees of success because of recurring instability problems. The network presented here seeks to minimize a global cost which is a function of the distances between plots in a given scan of data and the predicted track positions. Additionally, in this paper a novel technique is introduced for helping to alleviate the instability of Hopfield networks. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.

关键词： Traveling salesman problem

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Detecting and tracking low-observable targets using IR

Detecting and tracking low-observable targets using IR

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signal and data processing of small targets 1990

作者： Fernández, M.F. Aridgides, A. Bray, D. GE Advanced Technology Labs Electronics Parkway SyracuseNY13221 United States

ISBN: (纸本)9780819403568

Sensitivity to low-observable targets--given a sequence of N frames of pre-processed (e.g., spatial/time-filtered) but unthresholded data-may be enhanced by selecting, from among all possible paths traversing these frames, those containing any indication that a target may be present. However, since only upper bounds regarding target velocities are usually known, explicit formulation of all feasible paths (and accompanying confidence factors) becomes a formidable task even for small values of N. In this paper we address this problem by utilizing a Dynamic Programming ("Viterbi") algorithm to efficiently generate and evaluate, in an unthresholded fashion, all possible paths through the N frames. Trajectories are traced recursively by assigning accumulated trajectory scores to each entry in a given frame of data so as to maximize that entry's updated score. This Viterbi Track-Before-Detect procedure differs from standard Multiple Hypothesis Testing (MHT) methods in two ways. First, while in the MHT method the number of plausible paths grows exponentially (hence the need for introducing thresholds), in the Viterbi approach they remain constant, equal to the number of data entries in a frame. Second, whereas in the MHT method trajectories are updated by selecting for each existing trajectory the best current (thresholded) detection, in the Viterbi approach each current data value is updated with the best trajectory up to that point. Simulation results show that application of the Viterbi Track-Before-Detect algorithm over ten frames of IR data yields roughly a 7 dB improvement in detection sensitivity over conventional thresholding/peak-detection procedures. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.

关键词： Dynamic programming

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PASSDAT: Passive sensor data association for tracking-a PC software

PASSDAT: Passive sensor data association for tracking-a PC s...

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signal and data processing of small targets 1990

作者： Deb, Somnath Pattipati, Krishna R. Bar-Shalom, Yaakov University of Connecticut Department of Electrical and Systems Engineering U-157 260 Glenbrook Road StorrsCT06269-3157 United States

ISBN: (纸本)9780819403568

This paper describes a PC software package for the following problem: We are given multiple passive sensors, each with a number of detections at a given time. With each detection, there is an associated line-of-sight measurement originating from a source. The source can be either a real target, in which case the measurements are azimuth and elevation angles of the target, plus some measurement noise, or a spurious one, i.e., a false alarm. Position estimates of targets can be formed by associating measurements originating from it. Mathematically, the measurement-Target association problem leads to a generalized assignment problem. The problem of forming position estimates of multiple targets in a dense cluster, from passive sensor measurements at a given time, require at least three sensors. However, for three sensors, the three-dimensional assignment is known to be NP-complete, i.e., the complexity of the optimal algorithm increases exponentially with the size of the problem. The association problem is solved as a maximum likelihood estimation procedure;the likelihood function is maximized through the use of a near-optimal, iterative, and polynomial-Time three dimensional assignment algorithm which employs Lagrangian relaxation technique that successively solves a series of (polynomial time) generalized two-dimensional assignment subproblems. The algorithm is coded in Fortran and available as an interactive PC software package PASSDAT. In this paper we present performance results and graphical scenario description of a representative test case solved by PASSDAT. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.

关键词： Software packages

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Autonomous interpretation of side scan sonar returns

Autonomous interpretation of side scan sonar returns

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Symposium on Autonomous Underwater Vehicle Technology (AUV)

作者： A.R. Castellano B.C. Gray General Dynamics-Electric Boat Groton CT USA

The automatic interpretation of side scan sonar (SSS) returns is addressed. The proposed system combines signal detection techniques, feature extraction using SSS geometry, and a neural network classification algorithm for real-time detection and classification. Preliminary results were obtained by experimenting with actual SSS data. Applying the automated system to the data, the detection subsystem was able to detect properly the targets of interest as well as other bottom objects. The feature extraction subsystem helped the neural classifier separate targets from extraneous objects. However, in many instances, more resolution was needed to describe small targets accurately so that the neural classifier could classify correctly.< >

关键词： Sonar Sea floor Geometry Object detection Acoustic signal detection Underwater vehicles signal processing algorithms Vehicle dynamics Boats Magnetic sensors

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USE OF A VARIANCE ESTIMATOR FOR INTERFEROMETER ANGLE ACCURACY.

USE OF A VARIANCE ESTIMATOR FOR INTERFEROMETER ANGLE ACCURAC...

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Proceedings of the 1988 IEEE National Radar Conference.

作者： Greenspan, Marshall Holt Jr., Hugh D. Radza, Bernard P. Norden Systems Inc Norwalk CT USA Norden Systems Inc Norwalk CT USA

For radar applications requiring angle measurements on ground clutter over a large range swath or large elevation-angle extent, the single-pulse clutter-to-noise power ratio can be small due to low intercept grazing angles or low reflectivity. An approach is presented for using multiple returns to derive an angle variance estimate as a direct measure of data validity, rather than an amplitude threshold to better detect the presence of angle glint prior to angle estimation. The variance estimator can be used to detect the presence of spatially distributed interference returns such as those from a rain cloud. Results of a Monte Carlo signal simulation are presented to demonstrate the expected angle accuracy performance when the variance estimator is used in a phase interferometer radar. These results are compared to angle accuracy estimates based on an amplitude discriminant. small integration sample size and degradation due to thermal noise, clutter, and glint are considered. The results are applicable to measurements in either azimuth or elevation angle and to discrete targets with Swerling-I amplitude fluctuation.

关键词： signal processing

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Within-scene radiometric correction of LANDSAT Thematic Mapper (TM) data in Canadian production systems

Within-scene radiometric correction of LANDSAT Thematic Mapp...

引用

Earth Remote Sensing Using the Landsat Thermatic Mapper and SPOT Sensor Systems 1986

作者： Murphy, Jennifer M. Canada Centre for Remote Sensing 2464 Sheffield Road OttawaONK1A 0Y7 Canada

The Canada Centre for Remote Sensing (CCRS) has been using the scene-statistics approach, originally implemented in 19751 for destriping LANDSAT MSS data, for the routine correction of LANDSAT Thematic Mapper (TM) reflective band data. The 0.8% within-scene radiometric accuracy specified for Canadian production systems has been achieved for all but a small percentage of requested scenes2. A significant functionality of the processing methodology includes the correction for dark signal (DC) level shifts as a function of both detector and scan line number, by utilizing background reference level measurements available during the calibration period of each mirror scanning sequence. Additionally, forward and reverse mirror scans are treated independently. The effect of extended, bright targets such as snow, ice or clouds, is to cause a lowering of the background level by as much as 4 digital numbers (DN), with recovery times equivalent to approximately 2000 pixels. Hence, in the vicinity of the target itself, localized banding in phase with forward and reverse mirror sweeps is evident. A two-fold impact to the CCRS processing system occurs when the bright targets are at the edge of the scene, since the background reference level measured during the calibration period does not represent the offset for the imaging period of the sequence. The effects are, firstly, a more pronounced banding in those scan lines which image the bright target, and secondly, a forward/reverse banding superimposed over the entire scene, causing these scenes to fail the accuracy criterion. An automated procedure has therefore been adopted to detect when the forward/reverse banding would be outside specifications using the standard techniques. In such cases, forward and reverse mirror sweeps are then corrected with identical gain and offset correction parameters and the DC level shift corrections are applied. © 1986 SPIE. All rights reserved.

关键词： Mirrors

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Simultaneous high-speed digital recording of vocal fold vibration and speech signal

Simultaneous high-speed digital recording of vocal fold vibr...

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International Conference on Acoustics, Speech, and signal processing (ICASSP)

作者： S. Kiritani K. Honda H. Imagawa H. Hirose Research Institute Logopedics and Phoniatrics Faculty of Medicine University of Tokyo Tokyo Japan

A new method for the high-speed digital recording of the vocal fold vibration is presented. The method employs a solid endoscope, a solid-state image sensor and a digital image memory. About 100 frames of continuous image data with 50 × 50 picture elements can be stored in the image memory at one time. Image recording at a rate of 2000 frames per second was achieved using a small light source of a 250 W halogen lamp. The method enables to record the speech signal without special consideration on the camera noises, and also to observe the recorded image on the spot through CRT display. An example of the image data with simultaneously recorded speech and EEG signals are presented comparing the male and female voices, and the chest voice, falsetto and breathy voice.

关键词： Digital recording Speech Endoscopes Solid state circuits Image sensors Digital images Light sources Lamps Cameras Cathode ray tubes

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A dynamic programming-based DUR recognizer implemented on analog devices' DSP

A dynamic programming-based DUR recognizer implemented on an...

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International Conference on Acoustics, Speech, and signal processing (ICASSP)

作者： D. Morgan K. Leary Analog Devices Brown University Providence RI USA Analog Devices Norwood MA USA

This paper describes the use of Analog Devices' ADSP- 2100 digital signal processor in discrete utterance recognition applications. The practicality of implementing conventional 100, 300, 500, 1000, 2000, and 5000-word speaker-dependent recognizers is explored. The processor's functionality is demonstrated via the coordination and execution of tasks which include data acquisition, silence detection, feature extraction, amplitude normalization, and dynamic programming. A two-pass algorithm is presented which limits the computational burden of large vocabularies in the dynamic-programming phase. On the first pass decimated prototypes and candidates are compared to obtain a set of best matches. A complete dynamic programming search is then performed on this set during the second pass. An adequate hardware implementation is shown to consist of a small general-purpose ADSP-2100 processor board and separate memory board.

关键词： Digital signal processing Vocabulary signal processing algorithms Dynamic programming Prototypes Computer vision Throughput Detectors Finite impulse response filter databases

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AN INTERLEAVED-TRACE TIME-COMPRESSION RADAR DISPLAY

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IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS 1981年第5期17卷 724-726页

作者： LINDE, GJ WATERS, WM Search and Radar Branch Radar Division Naval Research Laboratory Washington DC 20375

Detection information from conventional surveillance radars is frequently presented in the form of a display known as the plan position indicator map. In this display, new data are displayed while data from previous scans fade from the display. Target blips typically persist for several scans, making possible operator integration or correlation. However, the noise from previous scans often masks signals from small moving targets. To avoid the loss in signal-to-noise ratio caused by the addition of noise to signal plus noise, a digital signal processing display unit has been designed and is presented here.

关键词： Displays Radar antennas signal to noise ratio Radar detection Surveillance Digital signal processing signal design Process design Airborne radar Aircraft

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