眼科高频环阵超声波数字化成像技术的研究

目的设计眼科高频环阵B超平台,实现超声波全程数字化处理。方法设计环阵换能器发射接收电路,将高频的超声回波信号经过前级放大后直接引出进行高分辨率、高速的模拟数字采样。信号数字化后,通过高速的现场可编程门阵列（field-programmable gatearray,FPGA）完成波束形成、动态聚焦、滤波、检波及对数放大等一系列信号处理。结果通过临床验证,眼科高频环阵B超平台图像横向分辨率0．2mm,侧向分辨率0．4mm,满足临床要求。结论环阵超声波数字化成像技术可提高图像分辨率和疾病检出率。     

一种基于胸阻抗法的心功能无创检测分析仪

目的为了经济、快捷、全面地实现心功能的无创检测,基于胸阻抗法成功研发了一种心功能无创检测分析仪,可方便地实现胸阻抗信号、心电信号、心音信号的同步检测分析,从而实现对患者心功能的无创综合评价。该方法无毒无创,操作简单,完全可以实现家用化普及。方法本文首先描述了系统的硬件模块构成,说明了胸阻抗信号的采集过程。其次,使用FPGA芯片与DDS芯片构成系统的控制与信号发生核心,指出了恒流源的精度等性能指标。再次,指出了胸阻抗信号处理的要点,运用互感原理实现干扰信号的隔离。最后,介绍了仪器软件功能,并展示了仪器软件实测结果。结果通过临床试验,对胸阻抗法与超声多普勒法检测的数据结果进行t检验,结果表明二者具有一致性。结论由于采用了先进的特征点判别方法,该设备具有较高的临床检测精度和较好的临床适用性,可满足临床心功能无创检测和评估的要求。     

基于盲信号分离的胎儿心电提取

本文提出了用盲信号分离提取胎儿心电的方法。首先研究了孕妇心电导联的特性 ,然后在此基础上设计了一个胎儿心电实时监护系统。由于使用了实时的盲信号分离算法 ,胎儿心电可以实时的被提取。一些试验结果表明该系统是有效的     

基于RLS-ANC自适应滤波的FECG信号提取方法

本文应用RLS-ANC(recursive least squares adaptive noise canceⅡation)自适应滤波方法提取胎儿心电(FECG)信号.该方法采用RLS-ANC自适应滤波消除母亲心电,提取胎儿心电信号.实验结果表明,本方法适应非平稳信号的能力强,收敛速度快,提取效果好于NLMS(normalized least mean squares)算法.     

胎儿心电监护系统的改进与提高

作者介绍一种先进的胎儿心电监护系统，对传统的胎儿心电监护系统作了改进和提高。该系统在胎儿心电的提取与处理方法上，解决了单纯用匹配滤波法难以提取到微弱的胎儿心电信号的问题。在系统的硬件方面，优化了信号放大器，重新设计和组建一套以４８０ＰＣ机为核心的胎儿监护系统。在软件上，采用了基于Ｗｉｎｄｏｗｓ平台，Ｂｏｒｌａｎｄ Ｃ＋＋的面向对象的软件编程。     

A field-programmable gate array based system for high frame rate laser Doppler blood flow imaging

This paper presents a general embedded processing system implemented in a field-programmable gate array providing high frame rate and high accuracy for a laser Doppler blood flow imaging system. The proposed system can achieve a basic frame rate of flow images at 1 frame/second for 256×256 images with 1024 fast Fourier transform (FFT) points used in the processing algorithm. Mixed fixed-floating point calculations are utilized to achieve high accuracy but with a reasonable resource usage. The implementation has a root mean square deviation of the relative difference in flow values below 0.1% when compared with a double-precision floating point implementation. The system can contain from one or more processing units to obtain the required frame rate and accuracy. The performance of the system is significantly higher than other methods reported to date. Furthermore, a dedicated field-programmable gate array (FPGA) board has been designed to test the proposed processing system. The board is linked with a laser line scanning system, which uses a 64×1 photodetector array. Test results with various operating parameters show that the performance of the new system is better, in terms of noise and imaging speed, than has been previously achieved.     

Fetal heart rate monitoring based on independent component analysis

In this paper, an algorithm based on independent component analysis (ICA) for extracting the fetal heart rate (FHR) from maternal abdominal electrodes is presented. Three abdominal ECG channels are used to extract the FHR in three steps: first preprocessing procedures such as DC cancellation and low-pass filtering are applied to remove noise. Then the algorithm for multiple unknown source extraction (AMUSE) algorithm is fed to extract the sources from the observation signals include fetal ECG (FECG). Finally, FHR is extracted from FECG. The method is shown to be capable of completely revealing FECG R-peaks from observation leads even with a SNR=-200dB using semi-synthetic data.     

基于嵌入式的多路肌电信号采集系统的设计

采用直接内存存取(direct memory access,DMA)和双口随机存取存储器(dual-port random access memory,dual-port RAM)相结合的方式设计了基于嵌入式的多路肌电信号采集系统。该系统由现场可编程门阵列(field-programmable gate array,FPGA)控制模数转换器(ADC)器件的采样时序;ARM作为主控器件采用DMA方式的数据采集机制,实现了上下位机的高速通信。本研究给出了数据采集接口设计方案,以及Linux操作系统下的DMA驱动程序和控制指令。实验表明该系统在采集肌电信息的同时对肌电信息进行算法处理并实时传输,明显提升了多路肌电信号采集系统的性能。     

Ultra-low-noise instrumentation and computer-based data acquisition and processing system for obtaining a noninvasive and intrauterine catheter fetal electrocardiogram

A fetal electrocardiogram (FECG) from the abdominal surface will be from 20 microVpp to unmeasurable. The intrauterine catheter signal will be from 50 microVpp to unmeasureable and will be corrupted with a significant direct current component of 10 to 200 microV. For electrophysiological information to be obtained from the abdominal and intrauterine catheter signals, the signals must be in a 0.05 to 100.0 Hz bandwidth. Because typical adult electrocardiogram systems have a noise specification of 5 to 10 microVpp from instrumentation, these systems are unacceptable for obtaining a FECG via the intrauterine catheter or noninvasively. Therefore, custom instrumentation has been developed with a noise specification of approximately 1.5 microVpp in a 0.05 to 100.0 Hz bandwidth. Design details of the custom instrumentation will be presented along with a laptop computer based data acquisition and signal processing system using LabVIEW. In addition, clinical data from the intrauterine catheter and noninvasive abdominal wall are presented to determine the feasibility of obtaining a FECG via the custom instrumentation. Clinical data obtained and documented indicates that after maternal electrocardiogram cancellation, a FECG with a good signal-to-noise ratio can be obtained in a diagnostic bandwidth of 0.05 to 100.0 Hz. Because the diagnostic bandwidth is preserved, electrophysiological information can be determined along with heart rate.     

便携式心电监测系统的硬件设计与实现

介绍了一种基于AD8232模拟电路和PSOC4 BLE可编程芯片的便携式心电监测系统的硬件设计,AD8232内置多个运放能够设计前置放大器、滤波电路和主放大电路,非常符合心电信号采集的要求,而PSOC4 BLE可编程芯片内含A/D转换、蓝牙等可编程模拟和数字电路,硬件设计体积非常小,便于携带,能够实现实时、低功耗和无线移动传输功能,又包括了软件滤波,处理后的波形验证了本设计的可行性。     

A Comparison of Single Channel Fetal ECG Extraction Methods

The abdominal electrocardiogram (ECG) provides a non-invasive method for monitoring the fetal cardiac activity in pregnant women. However, the temporal and frequency overlap between the fetal ECG (FECG), the maternal ECG (MECG) and noise results in a challenging source separation problem. This work seeks to compare temporal extraction methods for extracting the fetal signal and estimating fetal heart rate. A novel method for MECG cancelation using an echo state neural network (ESN) based filtering approach was compared with the least mean square (LMS), the recursive least square (RLS) adaptive filter and template subtraction (TS) techniques. Analysis was performed using real signals from two databases composing a total of 4 h 22 min of data from nine pregnant women with 37,452 reference fetal beats. The effects of preprocessing the signals was empirically evaluated. The results demonstrate that the ESN based algorithm performs best on the test data with an F1 measure of 90.2% as compared to the LMS (87.9%), RLS (88.2%) and the TS (89.3%) techniques. Results suggest that a higher baseline wander high pass cut-off frequency than traditionally used for FECG analysis significantly increases performance for all evaluated methods. Open source code for the benchmark methods are made available to allow comparison and reproducibility on the public domain data.     

基于独立成分分析和量子粒子群算法的胎儿心电提取

胎儿心电图(FECG)是反映胎儿心脏电生理活动的一项客观指标,获取的FECG受到母体心电图(MECG)的干扰,如何快捷、有效的提取FECG成为重要的研究课题。在非侵入方式下,FECG的提取算法中独立成分分析(ICA)算法被认为是效果最好的方法,但现有求解其分解矩阵的算法收敛性能都不太高。量子粒子群(QPSO)算法是一种收敛于全局的智能优化算法。因此,提出了一种结合QPSO的ICA方法。研究结果表明,与其他在非侵入方式下的主要提取算法相比,这种方法能更清晰准确地提取出有用信号,为胎儿的健康检测提供了更好的方法。     

Complete foetal ECG morphology recording by synchronised adaptive filtration

Present noninvasively measured indices of foetal stress are indirect and not sufficient. Foetal electrocardiography (FECG) is a potential noninvasive measurement of the foetus wellbeing which has been little utilised because of the difficulties of measuring it. The development of time-sequenced adaptive filters which are synchronised to the QRS complex by the use of Doppler echocardiography allowed the recording of relatively noise-free FECG. The paper describes the use of this technique for obtaining the complete complex of the FECG. Several sets of time-sequenced adaptive filters are combined to allow a multilead abdominal recording to produce a measurement system which rejects maternal ECG and enhances the FECG. Five subjects have been analysed, and their FECGs have been accurately reproduced with minimal changes of the filters' parameters.     

便携式超声背向散射骨密度仪设计

目的设计基于背向散射信号来评判骨密度情况的便携式超声骨密度仪,为实现超声骨密度仪的低成本和便携性提供一种解决方案。方法使用现场可编程门阵列(field programmable gate array,FPGA)作为主控以控制整个系统正常工作,配合信号调理、高速模数转换器(analog-to-digital converter,ADC)和USB传输电路,来实现高压脉冲控制模块、增益控制模块、信号采集、数据传输。最后对系统噪声和采集到的背向散射信号进行测试,并用松质骨样本进行骨密度测量的测试。结果系统整体尺寸为15 cm×10 cm×3 cm,数据传输速率可达60 MB/s,噪声水平低。结论设计了一种USB接口的便携式背向散射超声骨密度仪,在USB接口供电时,可以有效地获取背向散射信号。     

可穿戴式多参数监护装置信号处理平台的设计与实现

背景：可穿戴式多参数监护装置具有生理信号检测和处理、信号特征提取和数据传输等基本功能模块,可实现对人体的无创检测、诊断。 目的：将信号处理平台运用到对时效性和精确度要求较高的可穿戴式多参数监护装置中,提高ECG信号QRS波检测的检测速度和检定准确率。 方法：提出了一种新型可穿戴式多参数监护装置信号处理平台的设计思路,应用TMS320VC5509系列DSP系统实现改进后的LADT压缩算法结合小波变换和阈值检测ECG信号中QRS波的方法。 结果与结论：采用硬件DSP的方法显著提高了QRS波检测的速度,其结果可以用于穿戴式多参数监护装置异常心电检测的实际应用。     

Some ways of measurement unification in testing ECG analysers on the basis of test signals normalized according to amplitude/parameters and medical indications.

An urgency of test method development for testing the automated ECG analysers is substantiated; a generalized measurement algorithm used in measuring devices testing is discussed with interpretation as applied to ECG analysers. A general measurement scheme in analyser testing is given, tasks to create test ECG signals and develop methods and means for storage, reproduction and transfer of ECG signals to ECG analysers are advanced. A method to create, organize, store and reproduce the ECG signal data bank with the use of measuring and computing complex (MCC) is developed. A device for ECG signal reproduction and transfer (a generator) is made, with its structural diagram, work principles and main technological (metrological) characteristics shown.     

基于心电模块的心电采集系统设计

医用监护仪经常用心电模块进行心电采集分析。本文利用VC++实现计算机与监护仪专用心电模块进行串口通信,完成心电测量系统设计,实现了对心电数据的提取、处理和存储。经过多例心电信号的采集和处理,证实此系统运行稳定,结果与原来系统相同,其优点是更方便医学研究人员获取原始数据。     

先天性心脏病筛查系统设计

为提高医生筛查先天性心脏病的效率,设计一款基于卷积神经网络的先天性心脏病筛查系统。系统以软硬协同的方式实现心音、心电等生理参数的实时同步采集以及可视化和定量化分析。系统包含上下位机,下位机以FPGA为核心实现心音心电数据采集以及小波阈值去噪等预处理,上位机在Windows系统环境下以Python编程语言实现二阶谱特征提取、卷积神经网络二分类识别以及用户界面可视化显示。最终,系统对200名志愿者进行测试,准确率达到94.5%,特异度为95.9%,敏感度为93.2%。结果表明系统具有良好的表现,可以为临床先心病筛查提供有效的辅助。     

High-speed evaluation of track-structure Monte Carlo electron transport simulations

There are many instances where Monte Carlo simulation using the track-structure method for electron transport is necessary for the accurate analytical computation and estimation of dose and other tally data. Because of the large electron interaction cross-sections and highly anisotropic scattering behavior, the track-structure method requires an enormous amount of computation time. For microdosimetry, radiation biology and other applications involving small site and tally sizes, low electron energies or high-Z/low-Z material interfaces where the track-structure method is preferred, a computational device called a field-programmable gate array (FPGA) is capable of executing track-structure Monte Carlo electron-transport simulations as fast as or faster than a standard computer can complete an identical simulation using the condensed history (CH) technique. In this paper, data from FPGA-based track-structure electron-transport computations are presented for five test cases, from simple slab-style geometries to radiation biology applications involving electrons incident on endosteal bone surface cells. For the most complex test case presented, an FPGA is capable of evaluating track-structure electron-transport problems more than 500 times faster than a standard computer can perform the same track-structure simulation and with comparable accuracy.