Laser backscattering and transillumination imaging of human tissues and their equivalent phantoms

Surface backscattering profiles from a human forearm and transmission profiles through a human thumb, of red and near-infrared lasers, were determined. For the preparation of tissue-equivalent phantoms, white paraffin wax mixed with various wax color pigments were used. The surface reflectance profiles of a human forearm were matched with that of the phantom by mixing color pigments in various proportions. The reconstructed surface reflectance image of the phantom prepared by this procedure was similar to that of the human forearm. The transmission tomogram of the human thumb was obtained in fan-beam configuration by a near-infrared laser tomography system. Based on the horizontal scan of this tomogram, a two-layered phantom was made. The color composition of the phantom was so adjusted that its horizontal scan was matched with that of the thumb tomogram. The phantoms of complex tissues, prepared by this procedure, could be used for evaluation and calibration of new optical diagnostic imaging techniques.     

Multislice tomographic imaging and analysis of human breast-equivalent phantoms and biological tissues

A laser transillumination tomographic system, consisting of electrical, optical, mechanical, and software components, to obtain multislice images of tissue-equivalent breast phantoms and biological tissues, is developed. The tissue-equivalent phantoms are prepared from paraffin wax mixed with wax color pigments by matching their surface backscattered profiles as measured by multiprobe laser reflectometer, with that of respective tissues. The optical parameters of these phantoms are determined by matching their reflectance profiles with that as obtained by Monte Carlo simulation of optical scattering. For multislice tomographic analysis conical breast phantoms of height 80.0 mm and 80.0 mm base diameter with inclusions of different optical properties and dimensions are developed. The resolution of the inclusions in the tomograms depends on their sizes and optical parameters. The minimum size of the inclusion as detected by this procedure in a slice of diameter 50.0 mm is 3.0 mm. The structural variation as observed in the tomograms of phantoms of combination of biological tissues indicates its possible applications in detecting the abnormalities developing in human healthy soft tissues.     

The Study on Infrared Scattering of Red Tide

Based on analyzing the infrared laser’s transmitting characteristic in the seawater, the concept about the red tide infrared scattering coefficient is introduced. By analyzing the relationship between the red tide infrared scattering coefficient and the red tide’s density, we bring forward a new method of monitoring the red tide based on detecting the red tide infrared scattering coefficient. According to Mie scattering theory, the scattering efficiency factor and the scattering phase function of the red tide particles in the ocean are simulated and calculated. The result proves that, as the radiuses of the red tide particles increase, the scattering efficiency factor oscillates, and the swing decreases gradually, and then approaches to 2. From the results of the scattering phase function, it can find that the scattering of the red tide particles is mainly a forward scattering for the infrared laser. Therefore, by analyzing the scattering efficiency factor and the scattering phase function of the red tide particles in the ocean, it can prove the feasibility of this red tide monitoring method in theory.     

激光对红外成像制导跟踪系统的干扰技术研究

激光武器作为一种新型的光电对抗武器越来越受到人们的重视,但作为红外波段的干扰武器,目前研究甚少.本文以红外成像制导武器跟踪系统及其核心部件硅CCD为研究对象,对制导原理进行了概括,提出了激光干扰红外成像制导系统的三种途径.实验室以发射波长为10.6μm激光器作为干扰源对红外成像探测器及跟踪系统进行了干扰试验,给出了干扰效果图,并对影响干扰效果的因素进行了分析.     

Generation of Realistic Infrared Image for Moving Objects

Most of current methods are available for synthesizing the static infrared scene, but fail to simulate the infrared signature of the objects caused by motion. This paper presents a new method for generating realistic infrared image of moving objects. Considering various environmental factors, object geometry and structure, internal heat conditions and state of movement, an infrared image synthesis model for moving objects is established. Based on this model the rendering method for infrared image of this kind of objects is proposed. By incorporating the effect of atmosphere transmission and the noise mechanism of infrared sensor, the infrared images of the working aircraft and automobile are successfully generated from different viewpoint. Experimental results illustrate the potential of our method.     

Recognising partially occluded objects by rigid body relaxation matching

By representing 3D objects by a rigid-body model (RBM), application of probabilistic relaxation to satisfy the embedded spatial constraints in the RBMs for recognising partially occluded objects using range data was investigated. A computer simulated data set was used to illustrate the effectiveness of the proposed procedure.<>     

基于图像局部特征的红外小目标检测与跟踪算法

基于红外序列图像中小目标的典型特征,提出了一种新的红外小目标检测与跟踪算法.利用图像小目标的微分几何特性,计算图像的最小法向曲率,并以此为阈值,获得小目标的候选对象.之后利用多幅图像之间目标的相关性,在时间尺度上基于Kalman滤波算法,实现对目标噪声的过滤并实现目标的跟踪.最后对算法的有效性进行了验证.     

地面目标激光回波特征实验研究

对地观测激光扫描成像直接利用激光回波信息生成目标的灰度像，进行目标分类识别，因此，需要研究并建立激光回波特征与地面目标特征之间的关系模型。运用对地观测激光成像原理试验系统的实验结果分析了地面目标的脉冲激光回波的功率与波形等主要特征，探讨了目标后向散射率特性。通过机载信息获取与数据处理得到了由激光回波生成的局部区域灰度像，并且与被动红外成像结果的比较初步得到了地面目标与其激光回波特征之间的关系，从而为地面目标的激光三维成像与分类识别提供了部分技术支持。     

埋于介质中的二维多导体目标的微波成象

提出了一种埋于介质体内多导体目标几何特性和物理特性重建的迭代方法。应用Ｎｅｗｔｏｎ－Ｋａｎｔｏｒｏｖｉｔｃｈ方法求解非线性方程组,得到关于目标特性矢量的Ｆｒｅｃｈｅｔ导数,从而使非线性方程转僳“线线性”＋“迭代”的处理过程。     

类HED网络的热红外图像显著性人体检测深度网络

热红外图像中的人体目标易于观察显著性强,应用广泛,但受限于热红外设备的硬件,往往图像中的人体目标边缘模糊,检测效果较差,同时因为热红外的特殊成像原理,人体目标检测时极易受到发热物和遮挡物的干扰,检测的精度也无法得到保证。针对上述问题,本文提出了一种类HED（holistically nested edge detection）的热红外显著性人体检测网络。网络采用类HED网络形式,通过将不同比例的空洞卷积编解码模块进行残差相加形式,完成人体目标的检测任务。实验证明该网络可以有效地检测人体目标,准确地预测边缘结构,同时在发热物及遮挡物等环境下也具有较高的检测精度。     

红光固体激光实验设备的设计

目前市场上的激光倍频技术相关教学实验设备均以倍频输出绿光为主。本文介绍了一种腔内倍频红光固体激光实验装置的设计方法。采用平凹腔,通过808nm红外光端面泵浦掺钕钒酸钇(Nd:YVO4)激光晶体输出1342nm的红外激光,再通过腔内倍频表面镀1342nm和671nm增透膜的磷酸氧钛钾(KTP)倍频晶体,得到671nm的红光激光。     

Deep tissue photoacoustic imaging using a miniaturized 2-D capacitive micromachined ultrasonic transducer array

In this paper, we demonstrate 3-D photoacoustic imaging (PAI) of light absorbing objects embedded as deep as 5 cm inside strong optically scattering phantoms using a miniaturized (4 mm × 4 mm × 500 μm), 2-D capacitive micromachined ultrasonic transducer (CMUT) array of 16 × 16 elements with a center frequency of 5.5 MHz. Two-dimensional tomographic images and 3-D volumetric images of the objects placed at different depths are presented. In addition, we studied the sensitivity of CMUT-based PAI to the concentration of indocyanine green dye at 5 cm depth inside the phantom. Under optimized experimental conditions, the objects at 5 cm depth can be imaged with SNR of about 35 dB and a spatial resolution of approximately 500 μm. Results demonstrate that CMUTs with integrated front-end amplifier circuits are an attractive choice for achieving relatively high depth sensitivity for PAI.     

电视机手势遥控系统设计

提出了一种基于手势识别的交互方式用于遥控电视机,系统利用CMOS图像传感器捕捉用户手势信息,结合采集到的人手运动轨迹和手势识别技术,与标准手势的样本信息进行比对,从而判断出与之对应的控制信号,最后通过红外发射器完成对电视机各项基本功能的调控,实现了自然友好的人机交互操作,该系统使人们摆脱了传统的遥控器,可用于数字娱乐、...     

结合目标特性和局部背景类别预测的红外小目标检测

探索了一种结合目标特性和局部背景类别预测的红外小目标检测算法。具体研 究了红外天空小目标检测中屏蔽地物虚警的问题。在复杂的红外场景中,地面物体由于复杂多变造成 的虚警会严重影响系统的探测灵敏度和鲁棒性。如果仅从目标特性入手,难以滤除地物虚警。首先利 用新 Top Hat 变换提取出潜目标。然后,对每个潜目标,一方面利用目标特性获得一种潜目标为真实目标的 可能性度量,另一方面考虑潜目标一定大小的邻域背景,根据对背景类别(天空或者地物)的预测获得 另一种可能性度量。最后,结合两种度量滤除虚假目标。实验表明,相比仅考虑目标特性的算法,本文 算法的探测性能有了很大提升。     

红外序列图像中基于形状的人体检测

对红外序列图像中的人体检测问题进行了研究,提出一种新的人体检测方法.首先采用自适应高斯混合模型对序列图像中背景进行建模,在准确分割出前景运动目标的基础上,提出了一种新的人体形状表达模型,充分考虑了多个人体发生粘连或互相遮挡的情况,并用亮度投影的方法对其进行分离;以人体表达模型作为输入向量,构建支持向量机(SVM,Support Vector Machine)对人体进行分类判别.不同红外视频序列的检测结果表明了所提出算法在单个人体和多人体情况下均具有较好的鲁棒性和可行性.     

The Interaction of Static and Alternating Electric Fields with Biological Systems

A discussion is presented regarding the presence of natural and man-made electric fields in our environment. It is seen that biological objects readily come into contact with such fields. The interaction of some biological objects with electric fields is presented as well as original experimentation in this area. One experiment discussed deals with the influence of a 245 V/in (96.5 V/cm) electric field on the glucose concentration (as measured by per cent transmission) of human red blood cells. The data presented show an influence by the field. The second experiment discussed deals with the behavioral manifestations of electric fields on rats. An approach-avoidance procedure is utilized. The data presented shows an avoidance response at a high electric field intensity (4.5 kV/in) (1.77 kV/cm). Practical applications of this area of study are also presented.     

Calculations of Infrared Laser Beam Scattering from Rough Dielectric Objects

The coherent and incoherent scattering cross sections of Infrared Laser Gaussian beam scattering from arbitrarily shaped convex dielectric objects with rough surfaces are investigated by using plane wave spectrum method and physical optics approximation. In the paper, the infrared laser scattering cross sections of rough sphere are calculated at 10.6 μm , and the influence of the beam size, permittivity, and polarization as well as roughness parameters is analyzed numerically. When the beam size is much larger than the size of object, the results in the paper can reduce to those of an incident plane wave. On the other hand, for the case of roughness statistical parameter close to zero, only the forward scattering has a parent difference compared with the result of gaussian beam scattering from smooth sphere.     

Multiwavelength light emitters for scanning applications fabricatedby flipchip bonding

We present a multiwavelength light source which was fabricated using a self-aligned flipchip bonding technique. The device consists of an InGaN-GaN light-emitting diode emitting light at around 420 nm, on top of which we flipchip-bonded a monolithically integrated red/infrared dual-beam laser. The upper two lasers were built by selective removal of the red laser, and subsequent regrowth of an infrared laser structure. Since all processes, including the deposition of the PbSn solder bumps for bonding, were based on photolithographic precision, tight alignment tolerances of ±μm in the lateral direction could be fulfilled between the ridge waveguides of the three light emitters. For a high-speed color scanning system, this is an important design criterion because it will allow the use of a single scanning optics for the three laser beams     

利用激光器阵列方法测量烟幕对红外辐射的干扰效能

针对目前常用的单通道和多通道激光器测量方法的机理和无法解决的实时测量问题,提出了利用激光器阵列方法测量烟幕对红外辐射的干扰效能的思想。利用红外激光器均匀化整形等技术实现了对烟幕干扰红外成像时红外透过率的实时测量,解决了由于烟幕在红外成像视场中不断变化所带来的透过率测量随机性问题。通过计算典型试验条件下各方法的测量结果,给出了测量精度改进的定量分析。     

Location-oriented coordination in pervasive environments for collaborative work scenarios

Mobile or pervasive environments are inherently characterised by a high degree of dynamics and frequent changes in the environmental properties. This makes collaborative work of mobile users eminently difficult as the coordination of their work processes needs to adapt steadily to these changing circumstances. As location is one of the most critical changing context dimensions, this adaptive coordination and subsequent re-orientation are mostly based on distinctive temporal and spatial objects (the so-called Schelling points). The contribution of this article is to show the benefit of exploiting the human behaviour of using spatial objects for coordination (which we refer to as location-oriented coordination). We present an approach for which we implemented the location-oriented coordination considerations as a coordination pattern embedded in a coordination architecture, which serves as a runtime environment. By adopting this approach in a representative collaborative work scenario (in the domain of emergency management) and by presenting results from user tests we show its applicability and benefit.