Dissertations / Theses on the topic 'Bio-medical signal'

В работе предложен критерий оценки качества метода структурной идентификации биомедицинских сигналов с локально сосредоточенными признаками с помощью цифрового нелинейного фильтра. Выполнена экспериментальная проверка качества структурной идентификации при задании различных параметров нелинейного фильтра.
The quality evaluation criterion for the method of structural identification of bio-medical signals with localized features using the digital non-linear filter is proposed in this study. The quality of structural identification in the process of setting various parameters of the non-linear filter is experimentally verified.

Les techniques d'acquisition des signaux médicaux sont en constante évolution et fournissent une quantité croissante de données hétérogènes qui doivent être analysées par le médecin. Dans ce contexte, des méthodes automatiques de traitement des signaux médicaux sont régulièrement proposées pour aider l'expert dans l'analyse qualitative et quantitative en facilitant leur interprétation. Ces méthodes doivent tenir compte de la physique de l'acquisition, de l'a priori que nous avons sur ces signaux et de la quantité de données à analyser pour une interprétation plus précise et plus fiable. Dans cette thèse, l'analyse des tissus biologique par spectroscopie RMN et la recherche des activités fonctionnelles cérébrales et leurs connectivités par IRMf sont explorées pour la recherche de nouveaux bio-marqueurs. Chaque information médicale sera caractérisée par un ensemble d'objets que nous cherchons à extraire, à aligner, et à coder. Le regroupement de ces objets par la mesure de leur similitude permettra leur classification et l'identification de bio-marqueurs. C'est ce schéma global d'indexation et de recherche par le contenu d'objets pour la détection des bio-marqueurs que nous proposons. Pour cela, nous nous sommes intéressés dans cette thèse à modéliser et intégrer les connaissances a priori que nous avons sur ces signaux biologiques permettant ainsi de proposer des méthodes appropriées à chaque étape d'indexation et à chaque type de signal
The medical signal acquisition techniques are constantly evolving in recent years and providing an increasing amount of data which should be then analyzed. In this context, automatic signal processing methods are regularly proposed to assist the expert in the qualitative and quantitative analysis of these images in order to facilitate their interpretation. These methods should take into account the physics of signal acquisition, the a priori we have on the signal formation and the amount of data to analyze for a more accurate and reliable interpretation. In this thesis, we focus on the two-dimensional 2D Heteronuclear Single Quantum Coherence HSQC spectra obtained by High-Resolution Magic Angle Spinning HR-MAS NMR for biological tissue analysis and the functional Magnetic Resonance Imaging fMRI images for functional brain activities analysis. Each processed medical information will be characterized by a set of objects that we seek to extract, align, and code. The clustering of these objects by measuring their similarity will allow their classification and then the identification of biomarkers. It is this global content-based object indexing and retrieval scheme that we propose. We are interested in this thesis to properly model and integrate the a priori knowledge we have on these biological signal allowing us to propose there after appropriate methods to each indexing step and each type of signal

La tomographie est la discipline qui cherche à reconstruire une donnée physique dans son volume, à partir de l'information indirecte de projections intégrées de l'objet, à différents angles de vue. L'une de ses applications les plus répandues, et qui constitue le cadre de cette thèse, est l'imagerie scanner par rayons X pour le médical. Or, les mouvements inhérents à tout être vivant, typiquement le mouvement respiratoire et les battements cardiaques, posent de sérieux problèmes dans une reconstruction classique. Il est donc impératif d'en tenir compte, i.e. de reconstruire le sujet imagé comme une séquence spatio-temporelle traduisant son "évolution anatomique" au cours du temps : c'est la tomographie dynamique. Élaborer une méthode de reconstruction spécifique à ce problème est un enjeu majeur en radiothérapie, où la localisation précise de la tumeur dans le temps est un prérequis afin d'irradier les cellules cancéreuses en protégeant au mieux les tissus sains environnants. Des méthodes usuelles de reconstruction augmentent le nombre de projections acquises, permettant des reconstructions indépendantes de plusieurs phases de la séquence échantillonnée en temps. D'autres compensent directement le mouvement dans la reconstruction, en modélisant ce dernier comme un champ de déformation, estimé à partir d'un jeu de données d'acquisition antérieur. Nous proposons dans ce travail de thèse une approche nouvelle ; se basant sur la théorie des problèmes inverses, nous affranchissons la reconstruction dynamique du besoin d'accroissement de la quantité de données, ainsi que de la recherche explicite du mouvement, elle aussi consommatrice d'un surplus d'information. Nous reconstruisons la séquence dynamique à partir du seul jeu de projections courant, avec pour seules hypothèses a priori la continuité et la périodicité du mouvement. Le problème inverse est alors traité rigoureusement comme la minimisation d'un terme d'attache aux données et d'une régularisation. Nos contributions portent sur la mise au point d'une méthode de reconstruction adaptée à l'extraction optimale de l'information compte tenu de la parcimonie des données -- un aspect typique du problème dynamique -- en utilisant notamment la variation totale (TV) comme régularisation. Nous élaborons un nouveau modèle de projection tomographique précis et compétitif en temps de calcul, basé sur des fonctions B-splines séparables, permettant de repousser encore la limite de reconstruction imposée par la parcimonie. Ces développements sont ensuite insérés dans un schéma de reconstruction dynamique cohérent, appliquant notamment une régularisation TV spatio-temporelle efficace. Notre méthode exploite ainsi de façon optimale la seule information courante à disposition ; de plus sa mise en oeuvre fait preuve d'une grande simplicité. Nous faisons premièrement la démonstration de la force de notre approche sur des reconstructions 2-D+t à partir de données simulées numériquement. La faisabilité pratique de notre méthode est ensuite établie sur des reconstructions 2-D et 3-D+t à partir de données physiques "réelles", acquises sur un fantôme mécanique et sur un patient

This thesis is concerned with the investigation of two types of eye movements; smooth pursuit, and saccadic eye movement, each of which was analysed under normal condition, and then after the administration of alcohol. Parameters of interest in a selected range were measured using the novel approaches developed in this thesis and the results of a series of different tests compared. Much of the early work done in this area was based on minicomputers. Obviously, a microcomputer based system would be welcome because of costs, and the fact that they are readily available in many hospitals and health centres. The work reported here was carried out using the BBC microcomputer system, since it is inexpensive and commonly used in UK health institutes. The experimental facilities constructed for the work of this thesis were driven by the intention of producing a system free from many of the weaknesses in existing procedures, and to develop an essentially new approach to the problem. The starting point of the research described depends on the fact that whenever the eyes are moved a signal appears at the two poles of the eyes. This signal is known as the resting potential, or standing potential, with the cornea several mV positive with respect to the back of the globe. This potential is generated by the retinal pigment epithelium. By influencing the eyes to move in certain directions, and at certain velocities and frequencies, information can be gathered by further analysis of the signal captured. The signal captured is found to be very small (in the μV range), therefore an amplification of the signal is required, the amplifier needed must have specific features to meet the requirement of high input impedance so the signal is not distorted. This was achieved using a specially designed instrumentation amplifier. Noise which is always present in the signal, was rejected using filtering in analogue and digital forms. The analogue filter was a Butterworth filter with a frequency passband in the range between 0.1-30Hz. The digital filter chosen was the Hanning Window type. To ensure the safety of the person taking the tests care must be taken to isolate all equipment, consequently the signal collecting electronics was powered by batteries. The collected signal was interfaced to the computer using the 1MHz BUS of the BBC microcomputer. A second computer was used so that one of them can process the captured signal while the other generates a moving spot on the screen of a monitor as a stimulus for eye movement The collected signals are then processed in both the time and the frequency domain. The use of frequency domain techniques is a particularly useful form of analysis in the treatment of eye movement potentials, and is shown to extend the information that can be extracted from such signals.

碩士
國立臺灣大學
電子工程學研究所
97
The application of VLSI technology in bio-medical instrumentation enables the emerging of the bio-MEMS and wireless technologies. By combining these technologies, personal remote sensing has become a popular research area. It applies an implantable bio-medical circuit for neural stimulation and uses RF signal to transmit recorded physiological signals. In such implanted bio-medical circuits, low power operation is very important because the heat spread caused by the implanted circuit will increase local temperature which may damage organs and neurons. This thesis presents a signal processor with area-efficient DC offset cancellation. For this processor, this work designs the building blocks of a low power 10-bit successive-approximation-register analog-to-digital converter (SAR ADC) and a low power decimation filter for bio-medical applications. In the 10-bit SAR ADC, an energy-saving capacitor array and a splitting comparator architecture is proposed to achieve low power consumption. The average switching energy of the capacitor array can be reduced by 68% compared to a conventional architecture. The splitting comparator consists of two gain paths, through which power saving for an A/D conversion is achieved by selecting the appropriate comparison path and disabling the unused path. The measured signal-to-noise-and-distortion ratio of the ADC is 58.4 dB at 500KS/s sampling rate with power consumption of 42μW from a 1-V supply. The ADC is fabricated in a 0.18-μm CMOS technology. A low-power decimation filter for portable electrocardiogram (ECG) monitoring applications is also presented. This decimation filter consists of two parts: front-end and back-end. The font-end filters noise to regain ECG signal while the back-end computes the direct current (DC) offset caused by the local oscillator (LO) leakage and subtracts it from the input. This makes the ECG signal stays within the allowable ADC input range. In addition, selecting the right decimation factors gives the most efficient design in terms of storage requirements and the number of multiplications per second (MPS). Finally, the functionality of the decimation filter is tested and verified with an Altera Stradix EP1S80 FPGA board and Tektronix TLA 715.

碩士
國立中央大學
機械工程研究所
93
Owing to the tiny molecular weight and volume of biomolecules and very low physiologic concentration in biomolecular interaction analysis, it is important to improve the detection limit of biosensing. In this thesis, we integrate high sensitivity transducers (with or without fluorescence label) and developed electro-optical (E-O) signal processors to enhance the resolution of optical metrology system. First, we develop an E-O detector in bio-medical detecting application. The E-O detector combines with a photomultiplier tube sensor and a developed circuit board including the analog current amplifier, analog to digital converter, and universal serial bus (USB) interface. The detector now can measure the light power down to 10-16W and has been used in the bio-luminescence system and biochip fluorescent scanning reader. Moreover, a microfluid biochip is used to verify and the signal-to-noise ratio of the fluorescent signal is improved with the amplitude modulation lock-in amplifying technique with the help of dual-phase lock-in amplifier, and therefore the detection limit of the fluorescence measurement is improved with 20 times better then that of a conventional system. Lock-in amplifier is a key E-O device, so, we develop a home-made digital lock-in amplifier based on a home-made 32-bit digital signal processing board with USB 2.0 interface to realize the digital lock-in amplifier technique in real-time data transmission. To develop label-free biosensing systems, we focus on high sensitivity surface plasmon resonance (SPR) biosensing to build a common-path SPR heterodyne interferometer with the above E-O devices. The SPR interferometer can detect the refractive index change of better than 10-6 by testing the nitrogen and argon gases. Besides, we compare the difference between the magneto-optical and E-O modulation light sources. Finally, a prototype of full-field heterodyne interferometer is developed.

碩士
國立中興大學
電機工程學系所
99
In recent years, the wireless communication technology has been developed with a very high speed. In accordance to the tendency towards an aging society, the wireless communications technology has been used in medical monitoring gradually, such as home health monitoring, telemedicine, bio-sensing, smart device near body and so on. Such devices are all with characteristics of low power consumption, low cost, and low complexity. Thus, we want to construct a smart bio-sensing system, which is wireless, tiny, and can be provided for more than one person to use at the same time. The bio-signal between users will not be interfered with each other. The sensing bio-signal will be sent to the smart analyzing system by wireless transmission. Once the unusual signal is detected, the smart analyzing system will send out a warning signal. The system can save a lot of medical officers and resources. This thesis accomplished the baseband receiver for wireless bio-medical signal transmission.Like the other wireless transmission standard, this thesis also considered the channel effect like AWGN, carrier frequency offset, and phase noise. To reduce the complexity of the baseband receiver, many algorisms have been carefully investigated, such as packet detector, the compensation and estimation for carrier frequency offset, energy detector, boundary synchronism, and dispreading. After the algorisms for various functions are determined, then it is verified and accomplished by Verilog and FPGA.

碩士
中原大學
電機工程學系
87
The objective of this dissertation is to design and implement the analog integrated circuit chips for the wireless bio-signal transmission system. By the integrating method, it can achieve minimizing the occupied area, consuming little power, making the cost down and using conveniently. The analog integrated circuit chips have been used in the medical system application to process the physiological signal. The source of the signal is most coming from the electrocardiograpy (ECG). All these designed analog integrated circuits are based on a generic CMOS two-stage operational amplifier (op-amp). Design and characteristics of the CMOS two-stage op-amp has been presented in this dissertation. By using the op-amp, other analog circuits could be constructed, such as instrumentation amplifier, gain amplifier, switched-capacitor lowpass filter, and A/D converter. They are all integrated into chips. Before the fabrication of chips, these building blocks had simulated by HSPICE. The simulation results must meet the specifications. Then draw the circuit layout and simulate again (such as verification of DRC, LVS and LPE) until all the performance meet the specifications. The fabrication of chips uses the UMC 0.5μm double-poly double-metal CMOS technology. In order to identify the performance of these chips, The experimental on-board system constructed by using discrete commercial chips and designed chips have been verified in this research. The results showed that it meets the system specification. It is proved that by the integrating method, the occupied area can be minimized, and the expense of the system can also be reduced. Also, it is convenient to use.

碩士
國立清華大學
電機工程學系
100
This thesis proposes a novel 0.9V 10-bit Successive Approximation (SAR) analog-to-digital converter (ADC) based on half junction splitting (J.S.) and half binary weighted capacitor digital-to-analog converter (DAC) architecture. The kick-back noise of this structure due to comparator is larger than other DAC structures, thus a modified rail-to-rail comparator is used to reduce kick-back noise. This ADC is implemented in sub-threshold to reduce power consumption. In addition, dummy comparators are used in different sections of DAC to reduce the offset voltage caused by different gain errors of different DAC sections. The pre-simulation shows that the power dissipation is 1.27μW, SNDR is 61.7dB, ENOB is 9.96-bit, and figure-of-merit (FOM) is 12.8 fJ/conversion step. The chip has been fabricated with TMSC 0.18μm 1P6M CMOS process. The chip area is 893�e893μm2 with pads, and the core area is 440�e430μm2. The post-layout simulation shows that the power consumption is 1.72μW, the SNDR is 59.1dB, ENOB is 9.53-bit, and FOM is 23.2 fJ/conversion step. Under 0.9V supply voltage and 100KS/s sampling rate, the measurement result shows that the power dissipation was 1.59μW, SNDR was 46.47dB, ENOB was 7.43-bit, and FOM was 92.2 fJ/conversion step. This chip worked under 0.6 V supply voltage and consumed only 0.783μW. This low-power ADC is suitable for bio-medical signal acquisition. This low-power ADC is suitable for bio-medical signal acquisition.

碩士
國立清華大學
電機工程學系
101
In recent years, the industry of the portable electronic devices for bio-medical signals monitoring has been significantly growing. For the requirement of these portable devices, low power dissipation and high hardware efficiency are the main goals of the circuit design for the bio-medical electronics. A 10-bit, 1.28MS/s successive approximation register analog-to-digital converter (SAR ADC) for the acquisition system of bio-medical signals is presented in this thesis. In this SAR ADC, the DAC is functioned by a tri-level monotonic switching capacitive architecture. Its average switching energy is 9.5% to that of conventional switching capacitive DAC (CDAC), while its capacitor amount is 25% to that of conventional switching CDAC. The SAR ADC was fabricated in TSMC 90nm CMOS technology. The whole chip area was 1mm2, while the core circuit area was 0.205mm2. At 0.7V and 1.28MS/s, the static experimental performance of this SAR ADC were DNL of 5.312/-1 LSB and INL of 6.559/-3.932 LSB; the dynamic experimental performance were SFDR of 56.51dB, SNDR of 47.13dB, and ENOB of 7.53 bit. The SAR ADC dissipated power of 9.44uW, and achieved FOM of 39.9fJ/conversion-step. For better performance, another 10-bit SAR ADC is presented and also fabricated in TSMC 90nm CMOS technology. To lessen the dynamic offset effect induced by asymmetric switching process of monotonic switching CDAC, the improved SAR ADC was formed by an offset adjustable comparator and a proposed tri-level alternative switching CDAC. The average switching energy of this CDAC was 13.5% to that of conventional switching CDAC. The whole chip area was 1mm2, while the core circuit area was 0.14025mm2. At experiment conditions of 0.5V and 1.28MS/s, this SAR ADC had DNL of 0.646/-0.929 LSB, INL of 1.556/-1.467 LSB, and its SFDR, SNDR, and ENOB were enhanced to 60.21dB, 50.78dB, and 8.14 bit, respectively. The power dissipation of this SAR ADC was 4uW, and the resulting FOM was improved to 11.078 fJ/conversion-step.

碩士
國立清華大學
電機工程學系
103
In recent years, the design on bio-medical electronics has been getting more emphasized, especially the relative application on mobile device or portable monitors for the on time bio-signal acquitsition system. Low power consumption and high hardware efficiency are the trend of the requirement of portable devices. A 0.5-V 10-bit, 1.28MS/s successive approximation register analog-to-digital converter (SAR ADC) for the acquisition system of bio-medical signals is presented in this thesis. A capacitor switching detection circuit mainly constructed by two auxiliary comparators is applied to determine whether the high weighted capacitor in DAC should join the switching process or not for different input voltage cases. Through this detection, the wasted switching power can be avoided and also promote the performance of SAR ADC. The SAR ADC is fabricated in TSMC 90nm CMOS technology, and it is 868μm × 868μm of area for whole chip and 260μm × 234μm for the core circuit. At 0.5V and 1.28MS/s, the post-layout simulation results of SAR ADC are DNL of 0.21/-0.30 LSB, INL of 0.28/-0.13 LSB, SFDR of 76.42 dB, SNDR of 61.54dB, ENOB of 9.93 bit, power dissipation of 3μW, and FOM of 2.4fJ/conversion-step. For experiment, it achieves DNL of 0.58/-0.43 LSB and INL of 0.84/-0.63 LSB, SFDR of 66.28dB, SNDR of 56.66dB, ENOB of 9.12 bit, power consumption of 3.86μW, and FOM of 5.59 fJ/conversion-step. In order to achieve better performance of SAR ADC, another 10-bit SAR ADC is presented and also fabricated in TSMC 90nm CMOS technology. The switching detect circuit is replaced by digital logic gates and lessen the analog circuit concerns such as matching and parastic capcaitors due to routing which induces from the two auxiliary comparators. The chip area are 868μm × 868μm for total and 238μm × 200μm for core circuit. At 0.5V and 1.28MS/s, its post-layout simulation DNL and INL results are DNL 0.20/-0.28 LSB、0.21/-0.16 LSB, respectively; SFDR of 79.06 dB, SNDR of 61.67 dB, ENOB of 9.95 bit, power dissipation of 3μW, and FOM of 2.36fJ/conversion-step. For experiment, it achieves DNL of 0.56/-0.59 LSB and INL of 0.57/-0.70 LSB, SFDR of 66.97dB, SNDR of 56.55 dB, ENOB of 9.1 bit, power consumption of 3 μW, and FOM of 4.38fJ/conversion-step.

The information extracted from the bio-potential signals such as ECG, EEG, ECoG, ERG and ENG is extensively used for health care and medical treatment purposes. The use of bio-potential acquisition systems is not only limited to the hospitals but also extended to the homes for ubiquitous health care. Therefor the demand of portable bio-signal measurement system is increasing. The key constituent to this kind of systems is the analog front-end (AFE). The analog readout front-end extracts the bio-signals directly from human body through electrodes and defines the extracted signal quality. The most critical block in an bio-potential acquisition system is the AFE as it is connected directly to the human body and the output this should be ready to feed the subsequent stages that are ADCs and DSPs. This block must operate under low power consumption with minimal added noise to ensure the better signal quality with enhanced battery life, when incorporated in portable bio-signal acquisition systems. In this dissertation a novel multi-function Analog Front-End is proposed. This analog readout front end is oriented to be employed in flexible and portable bio-potential signal acquisition systems. The essential contribution of this work is the new Forward Body Biased Current Mode Amplifier (FBBCMA) based on convention forward body biased technique for low-voltage operation. The proposed FBBCMA achieves very low noise performance because of inherent properties of current mode topology. Forward body biasing of MOS devices further reduces the flicker noise that is a critical concern in circuits operating at low frequencies. Low power consumption and other advantages are achieved by the aid of the forward body biasing and current mode topology. A complete analog readout front end is implemented and simulated using the standard TSMC 180nm parameters and P-Spice as simulator. This AFE consist of a pre amplifier followed by a band pass filter to enhance in band signals and reject the signals that are laying out of the band of interest. Tuneable bandwidth of AFE enables it to serve as the first stage in variety of bio-signal acquisition systems. The simulation results show that the designed circuits meet the basic requirements of the low power consumption under low noise operation for long time portable bio-potential recorders.

碩士
國立臺灣大學
電信工程學研究所
94
We use linear model to simulate two kinds of Bio-medical signals, and then to find certain parameters to differtiate each group of each kind of Bio-medical signals. We measure and store two kinds of Bio-medical signals—Signals from jetlock joints of performance horse, and those from knee joints of human bodies. This first kind consisit of 2 groups including the normal horses and those with synovitis especially windgall on the front legs, no lameness, and the other one 3 groups, the signals from normal knee joints, those from injured joints and others from those injured being treated by taping. Then we apply Autoregressvie process to model each kind of signals, and select 3 certain characteristic parameters from each domain – time domain, transform domain and frequency domain—to analyze and differentiate each group of each kind.

碩士
國立臺灣大學
電子工程學研究所
94
Wireless technique has greatly improved in recent years. Applications in many different field arise quickly. Biomedical-signal wireless sensor system is one of the hottest research targets. The objective of this thesis is to design a wireless interface suitable for biomedical signals. The requirements of such a interface are low power consumption、medium transmission speed and high precision. Frequency-shift-keying fits in with these requirements and is adopted. A fractional-N type phase-locked loop is used as the modulator. It has the advantages of convenience to change the frequency and high precision. Fractional-N architecture allows the lock speed、loop bandwidth and frequency resolution to be optimized at the same time. A delta-sigma modulator is also used to reduce noise. The receiver adopts direct conversion topology. Low noise amplifier enhances the weak received signal and a Gilbert mixer down-converts it to baseband by mixing it with the local oscillator signal. A limiting amplifier limits the down-converted signal to rail-to-rail level assembling the waveform of a square wave witch can be view as digital pulses. A counter-based digital demodulator extracts the data.