Showing papers by "National University of Defense Technology published in 1996"
20 May 1996
TL;DR: The experimental results show that the approach can detect spot target in the presence of clutter for low signal-to-noise ratio (SNR) and the probability of detection and false alarm is presented as ROC curves for sky, ground and sea clutter background.
Abstract: The morphological filters are a class of nonlinear signal processing algorithms, which have been applied extensively to computer vision, image processing, and more recently target detection. This paper presents a morphology-based algorithm for spot target detection in IR clutter. The algorithm utilizes a prior knowledge of target size to suppress background clutter and remove noise. The experimental results show that the approach can detect spot target in the presence of clutter for low signal-to-noise ratio (SNR). The probability of detection and false alarm is presented as ROC curves for sky, ground and sea clutter background.
19 citations
01 Jul 1996
13 citations
TL;DR: In this paper, a super-Gaussian-Bessel (SGB) beam with the form A exp [−( r w ) n ]J 0 (αr) is introduced and the relation of optimal n versus wα is obtained through numeric calculations.
11 citations
TL;DR: In this article, a hybrid search method based on a modified genetic algorithm combined with the SSDA concept and an effective correlation image tracker implemented by software is archived, and experimental results of the tracker using some IR image data are given.
Abstract: A high-speed image registration algorithm which determines the frame-to-frame translational motion in the image sequence is presented. Instead of the exhaustive search block-matching algorithms, we develop here a hybrid search method based on a modified genetic algorithm combined with the SSDA concept and an effective correlation image tracker implemented by software is archived. Experimental results of the tracker using some IR image data are given.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
11 citations
01 Jul 1996
10 citations
01 Jul 1996
8 citations
20 May 1996
TL;DR: A systematic study is performed about theoretical approaches and techniques for high resolution radar target recognition in guidance application about the method of Doppler compensation for moving target discrimination and the rule-based pattern recognition for vehicle-sized target identification.
Abstract: In our work summarized in this paper, a systematic study is performed about theoretical approaches and techniques for high resolution radar target recognition in guidance application. The method of Doppler compensation for moving target discrimination and the method of rule-based pattern recognition for vehicle-sized target identification are firstly introduced. Then the pattern recognition approach based on adaptive matched-filters is studied for target recognition when the radial length of target range profile is not long enough. Finally, the experimental results of recognition of tank target are given.
8 citations
01 Jul 1996
5 citations
14 Oct 1996
TL;DR: This work develops a real transform algorithm for calculating the discrete circular deconvolution by substituting the fast Fourier transform defined in the complex domain and it is shown that the computational cost is about half of the traditional FFT.
Abstract: Fast computation of the discrete deconvolution is very important in image/video signal processing. We develop a real transform algorithm for calculating the discrete circular deconvolution by substituting the fast Fourier transform (FFT) defined in the complex domain. It is shown that the computational cost of the algorithm is about half of the traditional FFT. Furthermore, the algorithm has a weak numerical stability.
5 citations
20 May 1996
TL;DR: In this paper, the adaptive digital beamforming techniques using sparse antenna subarray division are studied and one method that used is that of transformed constraint of subarray into conventional array constraint, and this is presented for the adaptive beamforming of subarrays.
Abstract: In this paper, the adaptive digital beamforming techniques using sparse antenna subarray division are studied. Based on the model of sparse antenna array to be given, three antenna subarray architectures are compared. The criterions were: realization simplicity, adaptive antijamming performance against multiple jammers. One method that used is that of transformed constraint of subarray into conventional array constraint, and this is presented for the adaptive beamforming of subarrays. The results of the method are compared and some useful conclusions are provided. A large number of computer simulation results demonstrate the performance of this proposed method.
5 citations
01 Jul 1996
TL;DR: In this article, different geometry nozzles used in CW hydrogen fluoride chemical laser are investigated, including the area ratio, area width, axis length and base width, and the power and small signal gain of a Fabry-Perot resonator.
Abstract: Different geometry nozzles used in CW hydrogen fluoride chemical laser are investigated. Four geometry parameters, including throat width; area ratio; axis length and base width are considered. The flow properties, laser outcoupling power and small signal gain (SSG) of a Fabry-Perot resonator are calculated. The results show that when throat width and area ratio increase, the power and SSG peak will decrease in varying degree; they also varied when axis length changed; larger base width is related to lower cavity pressure, and smaller base width is related higher cavity pressure.
14 Oct 1996
TL;DR: This paper presents an accurate 3D measurement method by a stereo camera system with a digital image processing subpixel technique, and the 3D position of the object is determined by the photogrammetric principle.
Abstract: Accurate measurement of 3D position of an object is very important for industrial quality control, robot vision and 3D movement analysis etc. Close range photogrammetry is one of the common techniques for this purpose. Coupled with digital image processing techniques, close range photogrammetry has been developing very quickly in the last decade and has more and more applications. In this paper, we present an accurate 3D measurement method by a stereo camera system with a digital image processing subpixel technique. With the method, the stereo camera system is accurately calibrated and rectified with a rectangular grid. The specified object masks are extracted accurately and automatically by a pattern recognition method. Finally, the object masks on each camera image are matched automatically and the 3D position of the object is determined by the photogrammetric principle.
14 Oct 1996
TL;DR: A new way to build a pyramid of an image and a new strategy of identifying the root nodes are developed, using the Gaussian filter function with changeable filter scales to decrease the loss of the original image information.
Abstract: Pyramid-based image segmentation is a kind of very precise, universal and efficient method. A new image segmentation approach based on this idea is presented. A new way to build a pyramid of an image and a new strategy of identifying the root nodes are developed. In this approach: (1) the Gaussian filter function with changeable filter scales is used to build a pyramid, so as to decrease the loss of the original image information; (2) the relationship among the pixels which are in both level-in and level-between is used to determine the root nodes. The new approach need not know the image information in advance. A satisfactory result can be obtained even in a low signal-to-noise ratio image.
TL;DR: This work proposes novel filters with wavelet point-spread functions to reform not only the phases of optical waves, but also the filters for amplitude, and transmittance functions of the filters are given.
Abstract: Saloma [Opt. Lett. 20, 1943 (1995)] proposed the concept of mirrors with point-spread functions that exhibit wavelet-related characteristics. We propose novel filters with wavelet point-spread functions. The mirrors are suggested to reform not only the phases of optical waves, but also the filters for amplitude. The transmittance functions of the filters, which are real and positive under some conditions, are given. Optical wavelet transforms can easily be made with these filters, and computer simulations for edge and corner extractions are given.
20 May 1996
TL;DR: An effective morphological filter is developed which removes the noise and clutter in infrared clutter in real time and is used for automatic target detection and tracking in IR image sequence.
Abstract: This paper describes a high speed image processing system for automatic target detection and tracking in IR image sequence. To detect and track moving targets in infrared clutter in real time, we have developed an effective morphological filter which removes the noise and clutter. After obtaining the potential objects, the system calculates their centroid and labels them. The architecture of the system consists of two units: the image acquisition and displaying unit and the image processing unit. The system captures the consecutive images in real time, detects and identifies objects within three or four frames, then tracks them at the video rate. The experimental results showed the effectiveness of this proposed system.
20 May 1996
TL;DR: In this article, the wavelet packets analysis theory is used to decompose the measurements into their trends and fluctuations in different resolution levels, thus KFB is applied respectively to the trends and the fluctuations, thus the measurement noise is easily attenuated with little or without attenuation of the location information.
Abstract: Multiple-model Kalman Filter Bank (KFB) is the conventional method in the area of maneuver target tracking. However, the KFB method is often faced with the dilemma between noise sensitivity and the accuracy of the temporal and spatial location of the maneuver. The difficulty, of dealing with this problem is due to the fact that the maneuver information of a target is often submerged in the measurement noise, especially when the measurements are acquired in low SNR case. With the wavelet packets analysis theory, the primitive measurements can be decomposed into two parts in a resolution level One is the "trend" of the measurements which is related to the true course of the target's moving track. The other is the "fluctuation" of the measurement which is related to the maneuver information of the target and the measurement noise. In the case of conventional KFB, measurements are processed in a single resolution level, thus, the noise components, the maneuver information components and the target location components of the measurements are weighted as the same to the KFB. With the wavelet packets theory, we can decompose the measurements into their trends and fluctuations in different resolution levels, thus KFB is applied respectively to the trends and the fluctuations So the measurement noise is easily attenuated with little or without attenuation of the location information anti maneuver information. Simulation tests and comparison between conventional KFB method and wavelet packets analysis method are also discussed in the paper to demonstrate practicality and advantage of the wavelet packets method.
01 Jul 1996
31 Mar 1996
TL;DR: An efficient program partitioning algorithm based on objects for distributed system is designed and program restructuring according to the parallel model is automatically implemented by the translator.
Abstract: The paper introduces object-oriented large-grain data flow model and a parallelizing translator for the model. We design an efficient program partitioning algorithm based on objects for distributed system. Program restructuring according to the parallel model is automatically implemented by the translator.
TL;DR: In this paper, a phase contrast method was used to measure the birefringent axis orientation in PANDA fiber with matching refractive index (MRI) and distinguishing characteristics were obtained by image analysis of side view image systems.
Abstract: In the paper, we gave a phase contrast method to measure the birefringent axis orientation in polarization-maintaining fiber (PMF) with matching refractive-index (MRI). The phase contrast intensity profiles in PANDA fiber and distinguishing characteristics were obtained by image analysis of side view image systems. Experiments and computer simulation showed that the difference between two crests of intensity profile was not only used for determining angular orientation but also for determining the direction of rotation. The angular resolution of orientation was less than 2 degrees in phase contrast method. The difference between geometric and birefringent axes in PMF would be the limit of accuracy in side view image system.
08 Oct 1996
TL;DR: An automatic high range resolution (HRR) target recognition algorithm is detailed and tested on a data set of five different aircraft and a super-resolution downrange profile of radar returns of HRR is obtained using the Prony model.
Abstract: An automatic high range resolution (HRR) target recognition algorithm is detailed and tested on a data set of five different aircraft. A super-resolution downrange profile of radar returns of HRR is obtained using the Prony model. Target features are extracted by the wavelet transform. The features consist of two parts: one reflects the detailed structure of the targets, the other shows the outline of the targets. A probabilistic neural network (PNN) with a simple data fusion technique is applied for target classification.
20 May 1996
TL;DR: The paper emphatically studies the way for solving the problem of track confusion in multiple targets tracking by using message fusion technique and suggests two fusion modes-cascade fusion and parallel fusion.
Abstract: The paper emphatically studies the way for solving the problem of track confusion in multiple targets tracking by using message fusion technique. The discussion is on the basis of measurement data of practical bistatic systems. At first the paper introduces the association algorithm used for multiple targets tracking in bistatic systems and points out that track confusion easily happens if dynamic state parameters are the only ones used for association process. Then it gives several association methods fusing data of target state, Doppler frequency (F/sub ds/) and radar cross-section (RCS). After analyzing characteristics of F/sub ds/ and RCS data, the paper suggests two fusion modes-cascade fusion and parallel fusion. Both modes can decide whether or not to use F/sub ds/ data according to its change. From one hundred statistical results it is clear that track confusion frequency drops greatly when using data fusion techniques.
01 Jul 1996
08 Oct 1996
TL;DR: Based on wide-band polarimetric radar, a model of the radar target's polarization structure is proposed and pseudo-eigenpolarization is used to describe the dynamic properties from which fuzzy-dynamic-features are extracted.
Abstract: Based on wide-band polarimetric radar, a model of the radar target's polarization structure is proposed. On this basis, pseudo-eigenpolarization is used to describe the dynamic properties from which fuzzy-dynamic-features are extracted. The experimental results show that the method of identifying aircraft is effective and feasible.
20 May 1996
TL;DR: A fusion algorithm is presented for asynchronous multi-sited-sensors target tracking based on extended pseudo measurement filter that can preserve the tracking of target even in a jamming environment.
Abstract: A fusion algorithm is presented for asynchronous multi-sited-sensors target tracking based on extended pseudo measurement filter. Even in a jamming environment it can preserve the tracking of target. The difference between the algorithm and MGEKF is discussed. Afterwards, in conjunction with a simplified joint probabilistic data association, the tracking of two cross moving targets in clutter was implemented.
08 Oct 1996
TL;DR: The multi-stage tracking technique proposed makes full use of measurement data in T/R and R stations under different condition of jamming, as a result the tracking precision of 3-D moving targets is increased.
Abstract: Under the condition of jamming the number of usable measurements in a T/R-R bistatic system is variable. Therefore it is necessary to study some location and tracking algorithms concerning different sets of measurement data. The multi-stage tracking technique proposed makes full use of measurement data in T/R and R stations under different condition of jamming, as a result the tracking precision of 3-D moving targets is increased. The performance of these algorithms is evaluated with the help of computer simulation for typical target paths.
14 Oct 1996
TL;DR: Two novel recognition methods, namely dynamic binary tree and dynamic multibranch tree methods, are introduced based on the hierarchical process principle and can be applied to over 20 classes of object with satisfactory results.
Abstract: Multi-class object recognition has long been a difficult subject in pattern recognition studies. Based on the hierarchical process principle two novel recognition methods are introduced in this paper: the namely dynamic binary tree and dynamic multibranch tree methods. Experiments have shown that these two new approaches can be applied to over 20 classes of object with satisfactory results.
08 Oct 1996
TL;DR: Adapt digital beamforming techniques using sparse antenna subarray division are studied and one method, that used the transformed constraint of subarray into conventional array constraint, is presented for the adaptive beamforming of the subarray.
Abstract: In this paper, adaptive digital beamforming techniques using sparse antenna subarray division are studied. Based on the model of sparse antenna arrays, three antenna subarray architectures are compared. The criteria were realization simplicity and adaptive antijamming performance against multiple jammers. One method, that used the transformed constraint of subarray into conventional array constraint, is presented for the adaptive beamforming of the subarray. The results of the method are compared and some useful conclusions are provided. Computer simulation results demonstrate the performance of this method.
05 Nov 1996
TL;DR: In this article, a time domain bispectrum estimation algorithm was used to analyze target impulse response, which could estimate accurately local scattering distribution of complex targets, and measured the response of several target models and a scale aircraft.
Abstract: With reference to the air target detection of ultra- wideband(UWB)/impulse radar, we discussed transient signal processing techniques. In weak UWB signal detection, wavelet transforms and high order spectrum estimation techniques were preferred. In target characteristic analysis, two algorithms of impulse response deconvolution, MCGM and DPREM, were presented. In this paper, a time domain bispectrum estimation algorithm was used to analyze target impulse response, which could estimate accurately local scattering distribution of complex target. A free field IR experimental system was used which was laid out in an anechoic chamber. With this system, we measured the response of several target models and a scale aircraft.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
14 Oct 1996
TL;DR: Through deeply analyzing the implicit parallelism of genetic algorithms, this paper paints out a few errors and solves the problem simply but strictly with a method of inductive inference
Abstract: Through deeply analyzing the implicit parallelism of genetic algorithms, this paper paints out a few errors in "Genetic algorithms in search, optimization, and machine learning", by D.E. Goldberg (Addison-Wesley Publishing Company, Inc., 1989), p. 40-1, and revises his inference process and the corresponding conclusion according to his idea of sliding window. Besides, this paper solves the problem simply but strictly with a method of inductive inference.