Smoothing random noise from human head scan data

In obtaining human head range data with a laser scanner, noise results from system errors and rough surfaces. The noise can be reduced with a suitable filter. Two aspects need to be considered in smoothing head scan data: one is finding a filter to eliminate noise without creating new artifacts; the other is determining the parameters of this filter to achieve optimal smoothing. The Gaussian filter has been shown to have unique characteristics which preserve the integrity of the data. A cross-validation method based on regularization theory has been derived for estimating the correct filter size for smoothing head range data. The authors discuss the justification and implementation of the statements above. Generalized cross-validation is derived in the two-dimensional case. Experimental results are presented that show the technique is effective and robust.     

Mining three-dimensional anthropometric body surface scanning data for hypertension detection.

Hypertension is a major disease, being one of the top ten causes of death in Taiwan. The exploration of three-dimensional (3-D) anthropometry scanning data along with other existing subject medical profiles using data mining techniques becomes an important research issue for medical decision support. This research attempts to construct a prediction model for hypertension using anthropometric body surface scanning data. This research adopts classification trees to reveal the relationship between a subject's 3-D scanning data and hypertension disease using the hybrid of the association rule algorithm (ARA) and genetic algorithms (GAs) approach. The ARA is adopted to obtain useful clues based on which the GA is able to proceed its searching tasks in a more efficient way. The proposed approach was experimented and compared with a regular genetic algorithm in predicting a subject's hypertension disease. Better computational efficiency and more accurate prediction results from the proposed approach are demonstrated.     

浅谈基于点云数据的房屋三维建模

基于点云数据处理的三维重建技术突破了基于二维投影信息对目标物体建模在几何精度方面的瓶颈,重新构建出准确性更高、真实感更强的三维场景,可应用于工程项目的模拟仿真、规划、结构分析,或GIS展示、虚拟设计、场景还原等领域。因此,如何实现快速且自动化程度较高的真实再现三维模型的重建技术越来越多的受到人们的关注。     

浅谈基于点云数据的房屋三维建模

基于点云数据处理的三维重建技术突破了基于二维投影信息对目标物体建模在几何精度方面的瓶颈,重新构建出准确性更高、真实感更强的三维场景,可应用于工程项目的模拟仿真、规划、结构分析,或GIS展示、虚拟设计、场景还原等领域。因此,如何实现快速且自动化程度较高的真实再现三维模型的重建技术越来越多的受到人们的关注。     

基于三维光学信息的人体姿态快速测量

汽车中人体姿态三维测量对汽车座椅设计的舒适性评价具有重要的意义。为了快速准确地获取车内人体三维数据,文中采用一种基于双目视觉的立体三维数据获取方法,该方法将结构光与标记点相结合,实现了人体三维点云快速重建以及三维姿态(距离、角度)自动快速测量。实验结果表明,该方法在距离2 m以上,测量范围1.5 m×2 m时,人体姿态测量精度可以达到0.03 mm,满足了汽车人体姿态高精度三维数据采集的需求。与传统的汽车人体姿态三维测量方法相比,文中所使用的三维自动测量方法不仅自动化程度高,而且具有测量精度高、速度快、鲁棒性强的优点。     

基于IAA的毫米波人体三维高分辨成像算法

针对利用三维合成孔径技术成像的毫米波人体安检设备成像分辨力低的问题,提出一种将迭代自适应(IAA)技术与合成孔径成像技术相结合的波数域IAA成像算法。波数域IAA技术能估计出每个潜在位置所对应的信号源能量,具有分辨力高、旁瓣低且适合单快拍估计等优点。通过理论模型分析和仿真运算,将重构效果图与传统的匹配滤波方法重构效果图进行对比分析,验证了该算法的有效性;同时随着计算能力的提高,该算法的性能也得到提高。     

基于STM32的远程人体参数采集系统设计

日新月异的物联网应用及传感器技术,为健康信息采集、人员药品识别、精确定位奠定基础,使无边界感知医院和数字化智能医院成为可能.本文设计了一种基于物联网的远程人体参数采集系统.系统通过非接触采集人体的体温、脉搏、血压等信息,通过蓝牙无线传输模块传送给STM32主控系统,当人体的体温、脉搏或血压出现异常时,通过GSM报警模块向监测者发送信息,同时将数据上传至电脑中,并利用可视化工具进行显示.     

On the dynamics of human proximity for data diffusion in ad-hoc networks

We report on a data-driven investigation aimed at understanding the dynamics of message spreading in a real-world dynamical network of human proximity. We use data collected by means of a proximity-sensing network of wearable sensors that we deployed at three different social gatherings, simultaneously involving several hundred individuals. We simulate a message spreading process over the recorded proximity network, focusing on both the topological and the temporal properties. We show that by using an appropriate technique to deal with the temporal heterogeneity of proximity events, a universal statistical pattern emerges for the delivery times of messages, robust across all the data sets. Our results are useful to set constraints for generic processes of data dissemination, as well as to validate established models of human mobility and proximity that are frequently used to simulate realistic behaviors.     

Reconstruction of three-dimensional data for electrical impedance tomography

A two-dimensional reconstruction algorithm based on a modified version of the method of sensitivity regions is used to reconstruct data obtained from a three-dimensional finite element model. By using data obtained from off-drive-plane measurements an improved image of changes in resistivity on the drive plane is obtained.<>     

ROPES: a semiautomated segmentation method for accelerated analysis of three-dimensional echocardiographic data

Echocardiography (cardiac ultrasound) is today the predominant technique for quantitative assessment of cardiac function and valvular heart lesions. Segmentation of cardiac structures is required to determine many important diagnostic parameters. As the heart is a moving organ, reliable information can be obtained only from three-dimensional (3-D) data over time (3-D + time = 4-D). Due to their size, the resulting four-dimensional (4-D) data sets are not reasonably accessible to simple manual segmentation methods. Automatic segmentation often yields unsatisfactory results in a clinical environment, especially for ultrasonic images. We describe a semiautomated segmentation algorithm (ROPES) that is able to greatly reduce the time necessary for user interaction and its application to extract various parameters from 4-D echocardiographic data. After searching for candidate contour points, which have to fulfill a multiscale edge criterion, the candidates are connected by minimizing a cost function to line segments that then are connected to form a closed contour. The contour is automatically checked for plausibility. If necessary, two correction methods that can also be used interactively are applied (fitting of other line segments into the contour and searching for additional candidates with a relaxed criterion). The method is validated using in vivo transesophageal echocardiographic data sets.     

激光雷达扫描数据的快速三角剖分及局部优化

为了研究维激光雷达测量所得点云数据的三角构网,根据激光雷达逐行扫描特点,采用了改进的三角剖分方法,对点云数据进行不规则三角网格划分.基于激光雷达点云数据位置拓扑信息,分析了相邻扫描线之间数据点的相对位置关系,利用几何关系进行初步配对构网;并结合经典法则对初始网格进行局部优化,得到最终三角网;同时,对优化前后的三角网,提出一种新的评价法则进行剖分效果对比.结果表明,充分利用点云特点进行三角剖分可改进算法.所提出的剖分效果评价法可帮助检验构网质量.     

Method for locating a small magnetic object in the human body

A piece of thin acupuncture needle lodged under the right scapula of a patient could not be found in surgical procedures accompanied by studies of 30 standard X-ray images. To locate it, the authors mapped the magnetic field component normal to a plane lying above the object, using a superconducting quantum interference device (SQUID). Assuming that the needle could be modeled as a magnetic dipole, it was possible to infer its lateral position, depth, orientation, and magnetic moment. With this information, directed CT scans, high resolution X-ray films, and the subsequent surgical removal of the needle proved that it could be located in the body with an accuracy of about 3 mm     

An attempt to model the human body as a communication channel

Using the human body as a transmission medium for electrical signals offers novel data communication in biomedical monitoring systems. In this paper, galvanic coupling is presented as a promising approach for wireless intra-body communication between on-body sensors. The human body is characterized as a transmission medium for electrical current by means of numerical simulations and measurements. Properties of dedicated tissue layers and geometrical body variations are investigated, and different electrodes are compared. The new intra-body communication technology has shown its feasibility in clinical trials. Excellent transmission was achieved between locations on the thorax with a typical signal-to-noise ratio (SNR) of 20 dB while the attenuation increased along the extremities.     

On the performance of data receivers with a restricted detectiondelay

It is well known that the performance of a data receiver for an intersymbol interference (ISI) channel can depend strongly on the detection delay δ. For a discrete-time communication system, this paper derives a lower bound on the bit-error probability as a function of δ. This “restricted delay bound” is governed by a “restricted-delay distance” d(δ). In many instances, it improves upon Forney's (1972) bound, which is governed by the minimum distance d_min. For instance, for partial-response channels, d(δ) does not converge to d_min even as δ→∞. For channels without spectral zeros, a finite detection delay suffices for d(S) to coincide with d_min. For all finite δ, d(δ) is determined by a finite number of error patterns and may be computed in a straightforward manner. Unlike d_min, d(δ) depends on the phase characteristics of the channel. Minimum phase is proved to maximize d(δ). The lower bound is generalized to discrete-time channels with colored noise and to continuous-time channels. The effect of transforming a continuous-time channel into a discrete-time channel is discussed. Transformation via a matched filter, as in the ISI canceller and a Viterbi detector due to Ungerboeck and MacKechnie (1973), is shown to result in poor restricted-delay properties. Implications of these results are illustrated by means of examples     

Reconstruction of two- and three-dimensional images from synthetic-collimator data

A novel SPECT collimation method, termed the synthetic collimator, is proposed. The synthetic collimator employs a multiple-pinhole aperture and a high-resolution detector. The problem of multiplexing, normally associated with multiple pinholes, is reduced by obtaining projections at a number of pinhole-detector distances. Projections with little multiplexing are collected at small pinhole-detector distances and high-resolution projections are collected at greater pinhole-detector distances. These projections are then reconstructed using the ML-EM algorithm. It is demonstrated through computer simulations that the synthetic collimator has superior resolution properties to a high-resolution parallel-beam (HRPB) collimator and a specially built ultra-high-resolution parallel-beam (UHRPB) collimator designed for our 0.38-mm pixel CdZnTe detectors. It is also shown that reconstructing images in three dimensions is superior to reconstructing them in two dimensions. The advantages of a high-resolution synthetic collimator over the parallel-hole collimators are apparently reduced in the presence of statistical noise. However, a high-sensitivity synthetic collimator was designed which again shows superior properties to the parallel-hole collimators. Finally, it is demonstrated that, for the cases studied, high-resolution detectors are necessary for the proper functionality of the synthetic collimator.     

三维粒子动态分析仪的原始数据开发

三维粒子动态分析仪(3-Dimensional Particle Dynamic Analyzer)是利用激光多普勒频移原理,来测量两相流动中球形粒子的速度、粒径、浓度等参数,从而进一步得到三维湍流流动中粒子动态特性的一种激光测速设备。在其采集过程中自动建立的数据文件是以二进制形式存贮的,而且记录的都是每个球形粒子的信息,不能直接求平均及湍流计算。本文给出了处理这些数据的基本方法,通过编制的C语言程序得到各测点所通过的粒子数、三维速度、湍流特性以及相对体积流量,为PDA数据软件的进一步利用与开发提供了很大的方便。     

A spherical representation of a human body for visualizing movement

A three-dimensional human body model for displaying body movements on a computer graphics display is described. The surface of the body model is formed from overlapping spheres, yielding a realistically formed and shaded body image on a raster graphics display. An experimental model consisting of 310 spheres is articulated with 19 joints and 20 body segments. The properties of this model include joints which do not deform during movement, simple hidden surface removal, and efficient collision and contact detection. The model may also be placed in a planar polygon environment, displayed in shaded form, and tested for collisions with the environment. Applications in crash simulation and human movement simulation are indicated.     

On the size distribution in three-dimensional quantum-dot crystals

The size distribution function of nanodots in artificial three-dimensional (Si)Ge/Si and In(Ga)As/GaAs quantum dot crystals grown using templates with perfect periodicity is calculated. Pyramidal nanodots were modeled by cone-shaped clusters for which the Thomson formula was derived, which is necessary to determine the growth (dissolution) rate of clusters during Ostwald ripening. A comparison of the calculated curve with experimental histograms shows that the size distribution itself is formed during Ostwald ripening and is caused by features of Ge and InAs quantum-dot formation on preliminarily textured Si and GaAs substrates.     

On a reliable data communication broadcast system

This paper describes the design and implementation of a 3 KHz band HF data broadcast communication system, using a quantized frequency modulation, adaptive lattice equalizer together with forward error correcting code (FEC) to obtain a high link reliability and low error rate. A frequency diversity approach is also used in the selection of the timely best carrier frequency, and a microcomputer is implemented into the system for automatic best carrier acquisition, data transmission and clock synchronization, with minimum operator's attention. Extensive field experiments were conducted and experimental results indicate that the system can achieve, for daytime operation, a link reliability of 87–98%, with a probability of error between 10^?4 to 10^?5, depending upon data rate (50, 75bps) and FECs used. For night time operation, the link reliability reduces to from 65–93% with a probability of error down in the order of 10^?3.     

人体附近天线的辐射特性

使用解析方法研究了无线人体局域网（WBAN）通信中穿戴式天线的辐射特性。将人体简化为有耗介质椭圆柱体,采用椭圆柱面波展开和阻抗边界条件（IBC）,利用收、发天线的互易原理,推导了置于人体附近的短振子天线之方向性图和增益的解析表达式。计算了不同极化取向以及离人体不同间距对天线辐射特性的影响。经与软件仿真和实验测试结果对比,表明该解析方法的计算速度快、结果可信,能为无线人体局域网的天线设计提供依据。