基于支撑矢量机的天体光谱自动分类方法

天体光谱自动识别系统的主要目标是对天体进行分类和参数测量。文章提出一种新的基于支撑矢量机的非活动天体与活动天体的自动分类方法。在信噪比低的时候 ,由于红移值未知使得噪声与发射谱线难于辨别 ,因此不能单纯依靠寻找发射谱线来确定是否为活动天体。据此 ,在低噪声情况下对非活动天体与活动天体的区分成为难点。本方法结合主分量分析法和支撑矢量机 ,能够对红移值未知的活动天体与非活动天体比较有效地进行自动光谱分类 ,对天文界的大型巡天计划中的海量观测数据自动处理有比较重要的应用价值。     

High-frequency enhancement by an optical system for superresolution of temporally restricted objects

A system for superresolution of temporally restricted objects allows one to transmit ultrawideband optical signals (objects) through a narrow aperture. Such a system was proposed, improved, and implemented for one- and two-dimensional objects. Implementing frequency-plane enhancement in this system provides the ability of spatial filtering of ultrawideband objects. A method for spatial filtering in a system for superresolution of temporally restricted objects by use of a generalized Dammann grating is suggested. An experimental demonstration of high-frequency enhancement (high-pass filtering) of one-dimensional objects is presented.     

Simultaneous use of amplitude and phase to improve the validation process in a joint transform correlator

We present an alternative technique to enhance the discrimination performance in a JTC architecture, employed as a validation procedure. We define as complex objects those amplitude objects bonded to random phase masks. When using complex objects as reference inputs in a JTC optical validation system, correlation peak intensity and correlation peak shape become simultaneous key parameters to increase the discrimination ability of the system. Simulation results, comparing amplitude-only objects versus complex objects as inputs to the system, reveal the validity of our approach and show the sensitivity of the JTC architecture to the additional phase structures.     

Review of Progress in Acoustic Levitation

Acoustic levitation uses acoustic radiation forces to counteract gravity and suspend objects in mid-air. Although acoustic levitation was first demonstrated almost a century ago, for a long time, it was limited to objects much smaller than the acoustic wavelength levitating at fixed positions in space. Recent advances in acoustic levitation now allow not only suspending but also rotating and translating objects in three dimensions. Acoustic levitation is also no longer restricted to small objects and can now be employed to levitate objects larger than the acoustic wavelength. This article reviews the progress of acoustic levitation, focusing on the working mechanism of different types of acoustic levitation devices developed to date. We start with a brief review of the theory. Then, we review the acoustic levitation methods to suspend objects at fixed positions, followed by the techniques that allow the manipulation of objects. Finally, we present a brief summary and offer some future perspectives for acoustic levitation.     

利用偏振技术识别人造目标

提出了一种利用目标的偏振信息识别人造目标的新型方法。利用自制的多波段偏振CCD地面实验装置获取目标的偏振图像,并提取其中的偏振信息。由于人造目标和自然目标的偏振特性上有较大差别,因而根据这些信息,通过较常规的图像处理手段,即可很好地识别出图像中的人造目标。实验证明,该方法识别自然背景下的人造目标是相当有效的。     

Stereoscopic imaging through scattering media

We develop and experimentally test a method for three-dimensional imaging of hidden objects in a scattering medium. In our scheme, objects hidden between two biological tissues at different depths from the viewing system are recovered, and their three-dimensional locations are computed. Analogous to a fly's two eyes, two microlens arrays are used to observe the hidden objects from different perspectives. At the output of each lens array we construct the objects from several sets of many speckled images with a previously suggested technique that uses a reference point. The differences of the reconstructed images in both arrays with respect to the reference point yield the information regarding the relative depth among the various objects.     

An echolocation model for range discrimination of multiple closely spaced objects: transformation of spectrogram into the reflected intensity distribution

Using frequency-modulated echolocation, bats can discriminate the range of objects with an accuracy of less than a millimeter. However, bats' echolocation mechanism is not well understood. The delay separation of three or more closely spaced objects can be determined through analysis of the echo spectrum. However, delay times cannot be properly correlated with objects using only the echo spectrum because the sequence of delay separations cannot be determined without information on temporal changes in the interference pattern of the echoes. To illustrate this, Gaussian chirplets with a carrier frequency compatible with bat emission sweep rates were used. The delay time for object 1, T1, can be estimated from the echo spectrum around the onset time. The delay time for object 2 is obtained by adding T1 to the delay separation between objects 1 and 2 (extracted from the first appearance of interference effects). Further objects can be located in sequence by this same procedure. This model can determine delay times for three or more closely spaced objects with an accuracy of about 1 micros, when all the objects are located within 30 micros of delay separation. This model is applicable for the range discrimination of objects having different reflected intensities and in a noisy environment (0-dB signal-to-noise ratio) while the cross-correlation method is hard to apply to these problems.     

虚物成像适用理论的论证

关于虚物成像问题多有论文发表,但都忽略事先论证虚物是否具有光学成像物的属性,实物成像理论是否适用于虚物.这些文章都是直接把虚物当做实物而运用实物作图成像方法,举例阐明虚物作图成像方法.本文通过物与像之间的共轭关系,虚物成像公式的推导证明:虚物是光学成像之物,具有光学成像物的一切属性.可以应用所有实物成像理论和方法求解虚...     

基于矩和小波变换的目标图象识别

在图象目标的识别中,目标图象的不变矩对于具有旋转、尺度变换特性的目标具有良好特征匹配性能,但其识别准确度直接受到不变矩计算区域内的目标个数的影响.本文首先采用一维小波变换降噪并获取图象边缘,结合轮廓跟踪法(“爬虫法”)与投影法对图象进行区域分割获取各目标存在区域,再利用目标图象的不变矩进行目标识别,最后通过利用目标的主轴特性及质心变化计算目标的旋转角度及尺度变换倍率.通过仿真实验,证明方案可行且具有良好的识别性能.     

基于感兴趣区域的幅型比变换新方法

基于人类视觉系统对运动目标比较敏感的特性,提出了一种新的幅型比变换方法.综合时空信息提取视频序列中的运动目标,利用图像修复技术对被提取运动目标后的视频图像进行背景修补.采用插值算法以不同的方式分别缩放运动目标和修复后的背景,并将变换后的运动目标与背景相叠加合成相应幅型比的视频图像.实验结果表明：此方法避免了已有幅型比变换方法的缺陷,保证了变换后运动目标的无失真性,与人类的视觉感知有较好的一致性.     

Fast detection, position and classification of moving objects on production line

This paper presents a decision analysis method for detection, position and classification of moving objects on automatic production line. The decision is based on the coordinates of moving objects in the image frames, and the displacement information provided by servo motor control synchronized with a conveyor belt. Multiple objects to identify duplication or omission can be avoided. The method for smart packing robot can provide reliable location information of measured objects.     

一种利用窗口结构提取红外弱小目标的方法

在分析红外弱小目标检测的检测概率和虚警率的基础上,引入了一种基于窗口结构的红外弱小目标检测方法.该方法无需进行图像差分,利用局部小范围内目标相对背景的灰度变化检测目标,可以在较低信噪比的情况下获得较高的检测概率和较低的虚警率.实验表明了该方法的有效性.     

Technique for predicting the number of lightning strokes to extended objects

A technique is developed for predicting the lightning stroke distribution over a territory that is occupied by extended objects protected by lightning arresters (for example, high-voltage substations). It is shown that the techniques used to predict the number of lightning strokes to small objects located in a rated zone protected by lightning arresters are inapplicable to extended objects. The probability distribution is calculated for the number of lightning strokes to lightning arresters and to arrester-protected extended objects at different arrangements of the arresters.     

Properties of gravitationally bound dark compact ultra dense objects

We consider compact astrophysical objects formed from dark matter fermions of mass 250 GeV to 100 TeV or from massless fermions hidden by vacuum structure of similar energy scale. These objects have maximum stable masses of sub-planetary scale and radii of micron to centimeter scale. We describe the surface gravity and tidal forces near these compact ultra dense objects, as pertinent to signatures of their collisions with visible matter objects.     

A method of separating blended images in space debris observation

Due to the relative movement between space debris and background stars, the blending of objects and stars is ineluctable through observation. It brings down position accuracy of objects and even makes the tracking break down in worse conditions. In view of the difference of geometry between stars and objects in space debris observation, a technique for separating blended objects based on mathematical morphology is presented. It’s sufficiently flexible to be applied in image processing, and the blending images can be separated effectively with a high degree of centroid precision.

     

基于Logistic回归模型的Blazar天体的分类

从文献中收集了205个Blazar天体,包括142个BL Lac天体和63个平谱射电类星体(FSRQs).对这些天体的类别与它们的红移、射电5 GHz辐射流量、光学V波段流量、1 keV处X射线流量、X射线光子谱指数进行了相关性和Logistic回归分析.结果表明,对Blazar天体分类产生主要影响的因素是红移、射电5 GHz辐射流量和X射线光子谱指数,综合应用这三个物理量判别Blazar天体的分类的准确率可达到91.2%,得到的分类方程具有良好的预测效果,可以作为Blazar天体分类的一个重要的判据.而光学V波段流量和1 keV处X射线流量不能区分开BL Lac天体和FSRQs,它们与Blazar天体分类没有相关性.本文结果支持将BL Lac天体和FSRQs归为Blazar天体,不同类别的Blazar天体之间能通过一种演化序列相联系. 关键词： Logistic 分类 Blazar天体     

Exotic branes in string theory

Besides the familiar D-branes, string theory contains a vast number of other non-perturbative objects. While a complete classification is lacking, many of these objects are related to each other through various dualities. Codimension two objects play a special role, because their charges are no longer additive but are instead expressed in terms of holonomies of scalar fields, which is given by an element of the relevant duality group. In this paper we present a detailed exposition of these “exotic” objects, the charges they carry, and their connection to non-geometric compactifications. Despite the name “exotic branes”, these objects are in fact ubiquitous in string theory, as they can automatically appear when describing bound states of conventional branes, and as such may be of particular importance in describing the microscopic degrees of freedom of black holes.     

Binding in Charged Spherically Symmetric Objects

We consider the subject of self-binding in static, spherically symmetric objects consisting of a charged fluid. We have shown previously that in the case of a perfect fluid, only the localized part of the mass contributes to gravitational self-binding of such objects and that in the limiting case of objects comprised purely of electromagnetic mass, there is no gravitational binding. Here, we extend this result to the more general case of an anisotropic fluid. Our inspection of the Oppenheimer–Volkov equation allows tracking of both gravitational and non-gravitational contributions to binding of spherically symmetric objects and shows that those with pure electromagnetic mass cannot exist.     

超声波多点定位

介绍了利用超声波对多个物体进行定位的装置及方法,利用2个超声波收发传感器接收每个物体的反射波,并通过一定的算法计算出每个物体的位置.该装置可对二维空间内多个物体进行定位,并可对其测速、跟踪,甚至测出物体轮廓.     

Real-Time Laser Ultrasound Tomography for Profilometry of Solids

We studied the possibility of applying laser ultrasound tomography for profilometry of solids. The proposed approach provides high spatial resolution and efficiency, as well as profilometry of contaminated objects or objects submerged in liquids. The algorithms for the construction of tomograms and recognition of the profiles of studied objects using the parallel programming technology NDIVIA CUDA are proposed. A prototype of the real-time laser ultrasound profilometer was used to obtain the profiles of solid surfaces of revolution. The proposed method allows the real-time determination of the surface position for cylindrical objects with an approximation accuracy of up to 16 μm.