Multisensor data fusion for surface land-mine detection

Receiver operating characteristic (ROC) curves have been used to examine a novel target recognition system using a number of knowledge-based techniques to automatically detect surface land mines that are present in 30 sets of thermal and multispectral images. A summary of the results, graphed at a probability of detection greater than or equal to 96%, shows the false-alarm rates (FARs) obtained using various combinations of fusing sensors and neural classifiers averaged over the 30 images. The results show that using two neural-network classifiers on the input textural and spectral characteristics of selected multispectral bands, we obtained FARs of approximately 3%. Using polarization-resolved images only, we obtained FARs of 1.15%. Fusing the best classifier output with the polarization-resolved images, we obtained FARs as low as 0.023%. This result has shown the large improvement gained in the sensor fusion. Also, an improvement is shown by comparing these results with those reported in an existing commercial system     

Multisensor data fusion for physical activity assessment

This paper presents a sensor fusion method for assessing physical activity (PA) of human subjects, based on support vector machines (SVMs). Specifically, acceleration and ventilation measured by a wearable multisensor device on 50 test subjects performing 13 types of activities of varying intensities are analyzed, from which activity type and energy expenditure are derived. The results show that the method correctly recognized the 13 activity types 88.1% of the time, which is 12.3% higher than using a hip accelerometer alone. Also, the method predicted energy expenditure with a root mean square error of 0.42 METs, 22.2% lower than using a hip accelerometer alone. Furthermore, the fusion method was effective in reducing the subject-to-subject variability (standard deviation of recognition accuracies across subjects) in activity recognition, especially when data from the ventilation sensor were added to the fusion model. These results demonstrate that the multisensor fusion technique presented is more effective in identifying activity type and energy expenditure than the traditional accelerometer-alone-based methods.     

Multisensor fusion in the frame of evidence theory for landmines detection

In the frame of humanitarian antipersonnel mines detection, a multisensor fusion method using the Dempster-Shafer evidence theory is presented. The multisensor system consists of two sensors-a ground penetrating radar (GPR) and a metal detector (MD). For each sensor, a new features extraction method is presented. The method for the GPR is mainly based on wavelets and contours extraction. First simulations on a limited set of data show that an improvement in detection and false alarms rejection, for the GPR as a standalone sensor, could be obtained. The MD features extraction method is mainly based on contours extraction. All of these features are then fused with the GPR ones in some specific cases in order to determine a new feature. From these results, belief functions, as defined in the evidence theory, are then determined and combined thanks to the orthogonal sum. First results in terms of detection and false alarm rates are presented for a limited set of real data and a comparison is made between the two cases: with or without multisensor fusion.     

Multisensor towed array detection system for UXO detection

The multisensor towed array detection system (MTADS) was designed to be an efficient, sensitive tool for the detection and characterization of buried unexploded ordnance. It comprises arrays of total-field magnetometers and time-domain electromagnetic induction (EMI) sensors, associated navigation and data acquisition hardware, and a custom data analysis system. The MTADS has conducted eleven demonstrations and surveys. The system has shown the ability to detect ordnance at its likely self-penetration depths with a probability of detection of 0.95 or better The model-derived positions and depths of the detected ordnance items are generally well within the physical size of the targets, making remediation much quicker and less costly than with standard techniques. Data sets corresponding to many of the MTADS surveys are available to others in the field     

Multisensor integration and fusion model that uses a fuzzyinference system

An intelligent multisensor integration and fusion model that uses fuzzy logic is developed. Measurement data from different types of sensors with different resolutions are integrated and fused based on the confidence in them derived from information not usually used in data fusion, such as operating temperature, frequency range, fatigue cycles, etc. These are fed as additional inputs to a fuzzy inference system (FIS) that has predefined membership functions for each of these variables. The output of the FIS are weights that are assigned to the different sensor measurement data that reflect the confidence in the sensor's behavior and performance. A modular approach is adopted. It allows adding or deleting a sensor, along with its fuzzy logic controller (FLC), anytime without affecting the entire data fusion system. This paper presents a preliminary model that fuses the data from three different types of sensors that monitor the strain at a single location in a cantilever beam. This will be later extended to sensors that will be fixed at different locations on the same beam. The results from the proposed work are a stepping stone toward the development of generic autonomous sensor models that are capable of data interpretation, self-calibration, data fusion from other sources, and even learning so as to improve their performance with time. This work is aimed at the development of smart structural health monitoring systems, but has applications in diverse fields such as robotics, controls, target tracking, and biomedical imaging     

Robust data fusion for multisensor detection systems

Minimax robust data fusion schemes for multisensor detection systems with discrete-time observations characterized by statistical uncertainty are developed and analyzed. Block, sequential, and serial fusion rules are considered. The performance measures used, and made robust with respect to the uncertainties, include the error probabilities of the hypothesis testing problem in the block fusion case and the error probabilities and expected numbers of samples or sensors in the sequential and serial fusion cases. For different sensor observation statistics, the minimax robust fusion rules are derived for two asymptotic cases of interest: when the number of sensors is large and when the number of times the fusion center collects the local (sensor) decisions is large. Moreover, for the case of identical sensor observation statistics and a large number of sensors, it is shown that there is no loss in optimality, if local tests using likelihood ratios and equal thresholds are used in the sequential fusion rule. In all situations, the robust decision rules at the sensors and the fusion center are shown to make use of likelihood ratios and thresholds that depend on the least-favorable probability distributions of the uncertainty class describing the statistics of sensor observations     

Inexpensive fusion methods for enhancing feature detection

Recent successful approaches to high-level feature detection in image and video data have treated the problem as a pattern classification task. These typically leverage the techniques learned from statistical machine learning, coupled with ensemble architectures that create multiple feature detection models. Once created, co-occurrence between learned features can be captured to further boost performance. At multiple stages throughout these frameworks, various pieces of evidence can be fused together in order to boost performance. These approaches whilst very successful are computationally expensive, and depending on the task, require the use of significant computational resources. In this paper we propose two fusion methods that aim to combine the output of an initial basic statistical machine learning approach with a lower-quality information source, in order to gain diversity in the classified results whilst requiring only modest computing resources. Our approaches, validated experimentally on TRECVid data, are designed to be complementary to existing frameworks and can be regarded as possible replacements for the more computationally expensive combination strategies used elsewhere.     

模糊聚合及遗传算法在多传感器数据融合中的应用

文中给出了多传感器数据融合的一个模糊－－遗传算法，数据融合过程中的推理由模糊聚合函数完成，模糊聚合比传统的集合率中的并和交操作能更地地模拟答的量。模糊聚合函数的连接参数由遗传算法确定。这２个算法的优点是在信息源的可靠性１信息的 余度／互补性以及进行融合的分级结构不确定的情况下能够色近了倨的方法对信息进行融合。     

基于图像融合的运动前景检测方法

提出了一种有效的运动前景检测方法。该方法根据图像融合思想,将背景帧与监控视频的当前帧在R,G和B颜色通道分别进行融合,形成包含背景帧和当前帧视觉信息的单一融合图像。之后根据背景区域与前景运动目标在饱和度上存在较大差异的现象,使用大津算法分割融合图像的饱和度分量图,形成运动前景二值图。经形态学处理后,形成了目标区域较完整、背景干净的运动前景检测图。实验结果显示,该算法具有较好的前景检测性能,解决了背景减法过分依赖背景帧的缺陷。     

多传感器数据融合发展评述及展望

结合近年来国内外的研究成果,回顾数据融合研究的发展历程,介绍了多传感器数据融合的概念和模型,探讨了数据融合的多层式体系结构,对数据融合理论的发展和研究现状进行了分析,对未来研究方向进行了展望。     

基于时空域融合滤波的红外运动小目标检测算法

针对红外警戒与跟踪系统中的实时弱小运动目标检测问题．提出了一种基于时空域融合滤波的小目标检测算法。算法在空域上利用形态学Tophat滤波抑制背景增强目标．在时域上通过改进的帧间差分方法增强运动目标,时空域处理结果融合分割后,根据目标运动的连续性和规则性．利用相邻帧中可能目标点之间的位置关系判别目标。算法全面考虑到了运动小目标在时域与空域方面的特性,时空域融合增强后可大大提高目标信噪比。通过实际录取的云层背景飞机目标红外数据检测表明,时空域融合滤波方法能更有效地从复杂背景中检测低信噪比运动小目标,减小虚警率．抗噪声干扰能力强。算法易于硬件实现,能够有效地应用于红外搜索与跟踪系统的实时目标检测中。     

超声波探伤在机械手臂应用中的信息监测研究

为了进一步改进机械手信号采集的效果,文中进行了一种信号采集电路的改进设计,采用了1221x-002芯片完成传感电路,应用仪表AD620放大器实现前置放大,在滤波电路中应用频谱整形滤波器实现信号补偿,整形滤波具有以下特点:在实际的分辨率为7.4m~45.7m情况下,经过频谱整形滤波器滤波以后分辨率为5.6m~34.1m,分辨率得到明显的提高,即浅层和中层反射分辨率明显提高,但对深层反射率影响不大,这一研究对于改进信号采集的滤波效果具有一定的意义。     

Nonbinary error detection codes for data retransmission and biterror rate monitoring

The author discusses the use of (n, n-1) polynomial codes for data retransmission and bit error rate (BER) monitoring in nonbinary data transmission systems. For a particular type of polynomial code, called a simple polynomial code, a simple error detection scheme which exploits the Gray coding commonly employed in nonbinary data transmission systems can be devised. Even though its algebraic structure is the same as that of general (n, n -1) polynomial code, the simple polynomial code's performance, when using this detection algorithm, is either equal to or better than that of the corresponding general polynomial code, for data retransmission and BER monitoring. The improvement in the BER monitoring performance of the simple code relative to that of the corresponding general code increases as the data alphabet size becomes larger     

Multi-view and multi-plane data fusion for effective pedestrian detection in intelligent visual surveillance

For the robust detection of pedestrians in intelligent video surveillance, an approach to multi-view and multi-plane data fusion is proposed. Through the estimated homography, foreground regions are projected from multiple camera views to a reference view. To identify false-positive detections caused by foreground intersections of non-corresponding objects, the homographic transformations for a set of parallel planes, which are from the head plane to the ground, are applied. Multiple features including occupancy information and colour cues are extracted from such planes for joint decision-making. Experimental results on real world sequences have demonstrated the good performance of the proposed approach in pedestrian detection for intelligent visual surveillance.     

对于IP地址攻击有效的混合蜜罐入侵检测系统

提出在入侵检测系统中融合蜜罐技术并应用在分布式的网络环境中。主要目的就是通过单播IP地址攻击和组播的IP地址攻击对比单独入侵检测系统与融合了蜜罐技术的入侵检测系统检测攻击的有效性。混合蜜罐网络由Snort和Honeyd组成,Snort的作用是入侵检测而Honeyd组成蜜罐系统。Honeyd安装在Linux系统中,这个系统的传感器探测Snort和Honeyd是否传送数据到主数据库。使用NESSUS对实验数据进行分析。提供给管理员一种更有效的网络管理方式。     

A novel method for beat-to-beat detection of ventricular late potentials

A novel method for beat-to-beat detection of ventricular late potentials (VLP) from high-resolution electrocardiograms (ECGs) is presented. ECG signals from the X lead are first filtered using a bandpass filter, and then a time-sequence adaptive filter, to improve its signal-to-noise ratio. Eight features are extracted using wavelet transform, from the VLP time-frequency distribution of the filtered ECG signals, and used as inputs of specially designed artificial neural network for VLP recognition. The artificial neural network was trained and tested using clinical data, respectively. The results show that the presented method can detect beat-to-beat-based VLP with sensitivity of 80% and specificity of 77%, and the detection accuracy is 78%.     

An atrioventricular node model for analysis of the ventricular response during atrial fibrillation

This paper introduces a model of the atrioventricular node function during atrial fibrillation (AF), and describes the related ECG-based estimation method. The proposed model is defined by parameters that characterize the arrival rate of atrial impulses, the probability of an impulse choosing either one of the two atrioventricular nodal pathways, the refractory periods of these pathways, and the prolongation of the refractory periods. These parameters are estimated from the RR intervals using maximum likelihood estimation, except for the shorter refractory period which is estimated from the RR interval Poincaré plot, and the mean arrival rate of atrial impulses by the AF frequency. Simulations indicated that 200-300 RR intervals are generally needed for the estimates to be accurate. The model was evaluated on 30-min ECG segments from 36 AF patients. The results showed that 88% of the segments can be accurately modeled when the estimated probability density function (PDF) and an empirical PDF were at least 80% in agreement. The model parameters were estimated during head-up tilt test to assess differences caused by sympathetic stimulation. Both refractory periods decreased as a result of stimulation, and the likelihood of an impulse choosing the pathway with the shorter refractory period increased.     

网络安全检测与监控技术的研究

计算机网络的发展及计算机应用的深入和广泛,使得网络安全问题日益突出和复杂。现代网络安全是网络专家分析和研究的热点课题。首先阐述因特网的安全检测技术即实时监控技术和安全扫描技术的概念、工作原理以及防火墙系统的优势和不足;然后介绍能够主动测试系统安全且已实现的网络安全自动检测系统和入侵监控预警系统;最后总结网络安全维护的重要性。