De-noising of Impedance Cardiography Differential Signal and Detection of the Feature Points Based on Wavelet Transformation / 生物医学工程学杂志

Calculation of cardiac hemodynamic parameters is based on accurate detection of feature points in impedance cardiogram. According to these parameters, doctors can determine heart conditions, so it is very important to accurately detect the feature point of impedance differential signals. This article presents a process in which we used wavelet threshold method to de-noise signals, and then detected the feature points after six layers wavelet decomposition by using bior3. 7. The experimental data were collected from healthy persons in our laboratory and twenty two clinical patients in Chongqing Daping Hospital by using KF_ICG instrument. The results indicated that this method could precisely detect feature points whether it was from healthy people or clinical patients. This helps to achieve the application of noninvasive detection cardiac hemodynamic parameters in clinical treatments by using impedance method.

The principles and research status of noninvasive glucose detection based on near-infrared spectrum / 生物医学工程学杂志

It is of great clinical significance to investigate noninvasive glucose detection. As one of the most potential methods, the noninvasive glucose detection based on near-infrared has become a hot research area recently. In this paper the principles and research methods of noninvasive glucose detection based on near-infrared spectrum are introduced. With the comparison between the research status at home and abroad in recent years, we summarize and discuss crucial issues in near-infrared noninvasive glucose detection, such as the selection of measurement method, selection of measurement position and choice of wavelength, and, furthermore, setting up models.

Research progress on key technology of power and signal transmission in neuroprosthetic / 生物医学工程学杂志

The power and signal transmission technology is one of the key technologies in neuroprosthetic research. This paper proposes firstly the related theory of power and signal transmission technology in neuroprosthetic, then summarizes the three key aspects of the power and signal transmission technology in neuroprosthetic. After analyzed the development of the inductive wireless power harvesting technology, the wireless telemetry technology and the wireless power harvesting telemetry technology, the emphasis on research contents will be proposed and discussed, which will help accelerate the further research of prosthetic.

Review of the active locomotion system for capsule endoscope / 生物医学工程学杂志

This review summarized the progress of researches on the active locomotion system for capsule endoscope, analyzed the moving and controlling principles in different locomotion systems, and compared their merits and shortcomings. Owing to the complexity of human intestines and the limits to the size and consumption of locomotion system from the capsule endoscope, there is not yet one kind of active locomotion system currently used in clinical practice. The locomotive system driven by an outer rotational magnetic field could improve the commercial endoscope capsule, while its magnetic field controlling moving is complex. Active locomotion system driven by shape memory alloys will be the orientated development and the point of research in the future.

Study of principles of non-invasive glucose monitoring and instruments with the methods / 生物医学工程学杂志

Non-invasive blood glucose monitoring will be the development direction for detecting the blood glucose concentration of body in time. In this way, the concentration of the blood glucose can be controlled effectively, then the complicating diseases of diabetes can be reduced, so it is of great significance for diagnosis and treatment of diabetes. The recent developments of non-invasive blood glucose concentration monitoring technologies, including basic principles, results of verification test and instruments, are discussed, especially three methods with instruments facing market. The existing problems of these methods are also discussed. Finally, some difficult points of current non-invasive blood glucose monitoring methods are further discussed and the future trend of the technologies has been pointed out according to the above analysis.

An improved morphological edge detection algorithm of medical image based on multi-structure element / 生物医学工程学杂志

An improved edge detection algorithm is proposed in this paper for the medical images with strong noises and fuzzy edges. The algorithm modified the combination of morphological operations, so that the unclear edges of the images are avoided. In this paper is also introduced the algorithm of multi-structure elements which can reserve integrated edges from different directions of the images. Furthermore, the contrast enhancement and morphological filter processing are implemented. This method can detect the edges efficiently, keep the detected edges smooth and obtain coherent image edges. Experiments demonstrate that this edge detector has a better performance of noise reduction and keeps the edges more accurate than do the traditional edge detectors; thus its practicality is enhanced.

A discussion about key issues in retinal prosthesis / 生物医学工程学杂志

Retinitis pigmentosa (RP) and age-related macular degeneration (AMD) are two predominant causes of visual deterioration. Retinal prosthesis embeds a micro-electric chip or a micro-photoelectric diode array in the sub-retina or epi-retina, which is used to stimulate the remainder of inner retina, so as to restore some degree of sight. Retinal prosthesis has attracted most attention in the field of artificial visual function recovery, and along with deep-going research, many issues need to be resolved. In this paper, the theory of retinal prosthesis and the status quo of research in many countries are introduced, the key issues which influence the application of the retinal prosthesis are discussed in detail, and some notions and advices are presented.

A modified fast independent component analysis and its application to ERP extraction / 生物医学工程学杂志

Feature extraction of event-related potentials (ERP) plays an important part in both basic and clinical researches for cerebral neurophysiology. ICA is a method for separating blind signals based on signal statistic characteristics. In this paper, the fundamental principle, the discrimination condition and the practical algorithm of Independent Component Analysis are discussed. Then, a fast Independent Component Analysis algorithm (Fast ICA) is introduced. But like Fast ICA, its convergence is dependent on initial weight. We bring in a revision factor into the algorithm; thus the new algorithm could implement convergence on a largescale. In this paper, the revision factor is calculated by gradient. By modifying kernel iterate course, several iterations of Fast ICA are merged into one iteration of Modified Fast ICA, so the convergence of ICA will be accelerated. Finally, Modified ICA is applied to ERP extraction. The simulation shows that the convergence speed can be increased by using the improved algorithm.

Development of a video image system for wireless capsule endoscopes based on DSP / 生物医学工程学杂志

A video image recorder to record video picture for wireless capsule endoscopes was designed. TMS320C6211 DSP of Texas Instruments Inc. is the core processor of this system. Images are periodically acquired from Composite Video Broadcast Signal (CVBS) source and scaled by video decoder (SAA7114H). Video data is transported from high speed buffer First-in First-out (FIFO) to Digital Signal Processor (DSP) under the control of Complex Programmable Logic Device (CPLD). This paper adopts JPEG algorithm for image coding, and the compressed data in DSP was stored to Compact Flash (CF) card. TMS320C6211 DSP is mainly used for image compression and data transporting. Fast Discrete Cosine Transform (DCT) algorithm and fast coefficient quantization algorithm are used to accelerate operation speed of DSP and decrease the executing code. At the same time, proper address is assigned for each memory, which has different speed;the memory structure is also optimized. In addition, this system uses plenty of Extended Direct Memory Access (EDMA) to transport and process image data, which results in stable and high performance.

Review of the design of power supply in retinal implants / 生物医学工程学杂志

The energy supply for the stimulation arrays is the key component in retinal implants. Usually, the thin film solar cell is used to supply energy, but it can not supply enough stimulation power. One of the general idea of incident energy supply is radio frequency (RF) circuit. Another method is to convert near infrared (NIR) radiation and enable retina cell stimulation. In this paper, firstly, we aim at listing these two energy supply methods, and introduce the characteristics of RF circuit and NIR conversion method. Especially, we present the design procedure in detail. The next part is a discussion on the advantage and disadvantage of adopting these two methods. At last, we explicate the new research and application of the energy supply for the use as retinal implants, and we envisage the future.

Application of feedback techniques in motor function rehabilitation / 生物医学工程学杂志

Feedback is an important way of information transmission in motor function output. Movement-related information can be transmitted as proprioceptive, haptic, visual and/or audial information to the central nervous system for control and modification of the temporal and spatial precision of motor output. Here presented is a systematic discussion on the principle, technique and effect for some typical motor function rehabilitation methods such as treatment based on EMG feedback, robot-aided movement therapy, high-level perceptional feedback and motor training effect with 3-D virtual reality environment.

Suppression of geomagnetic field interference in the magnet locating system of the micro-magnetic capsule inside the alimentary tract / 生物医学工程学杂志

A method for the suppression of geomagnetic field interference is here-in introduced. It is designed for use in the magnet locating system of the engineering-based microcapsule inside the alimentary tract. This method marks the geomagnetic field interference levels by getting the static value. Then subtracting the static value from the dynamic value. The results of the experiment show that the method can assess the geomagnetic fi eld interference levels around thelocating waistcoat accurately. And the three-dimensional tracking trajectory shows that the method has greatly improved the accuracy of the capsule location inside the alimentary tract.

Three-dimension reconstruction of ocular fundus image / 生物医学工程学杂志

The mathematical model for 3D reconstruction of ocular fundus images is constructed according to both the reduced eye model and the simplified model of fundus camera optical system. The relationship between the images of emmetropic and ametropic eye and the true shape of ocular fundus retina is analyzed, and then the mapping relationship from 2D ocular fundus plan image to 3D surface image is obtained. As a result, the real example of 3D reconstruction for ocular fundus images is given. The max visual field of ocular fundus image for three-dimensional reconstruction is decided by the max visual field angle of fundus camera, which limits a size of the visual field of 3D reconstruction image and a range of z axis. According to the formulas of 3D mapping, the 2D data of ocular fundus image is mapped to 3D data and then veins mapping is carried out; thereafter, the 3D surface image of ocular fundus can be drawn immediately. This method makes use of the existing 2D imaging equipments to provide 3D surface image of patient's ocular fundus, and can provide ophthalmologist with beneficial reference and help to their clinical diagnosis and treatment.

Research progress of subretinal implant based on electronic stimulation / 生物医学工程学杂志

Subretinal prosthesis is one kind of retinal prosthesis, which means that a microimplant based on MEMS technology is inserted in the subretinal space to stimulate the optic nerve and elicit an electrical-evoked response on the cortical region. The subretinal implant is made up of extraocular part and intraocular part. As an important part, the latter consists of accessorial setting and stimulation chip that contains microphotodiode array (MPDA) and microelectrodes. The paper main body is made up of four parts. Firstly significance of the retinal prosthesis is given out; secondly fundamentals on both in retina physiology and retinal prosthesis theory are introduced simply. Then the key segment about the subretinal microimplant is presented in detail. In the third segment, first of all is its design concept, the second is fabrication of MPDA which consists of several parts. First is microscopic configuration, electric prototype schematic and chip image CMOS. The second is detailed fabrication flow with several special materials. Then is situation of its dimension. The fourth segment presents challenge and outlook.

Research and development of artificial retina material / 生物医学工程学杂志

The application of artificial retina was introduced. The principal characteristics of artificial retina material were reviewed in particular. Moreover, the recent research development and application prospect were discussed.

Application of Visualization Toolkit in three-dimensional reconstruction for medical images / 中国组织工程研究

Visualization of medical images has become an important method for the basic medical research as well as clinical diagnosis and treatment.Construction of the highly sophisticated three-dimensional(3D) models of the human body by computers has become an essential foundation for current medical research and disease treatment methods.Visualization Toolkit(VTK) is a kind of famous software in scientific visualization fields.It is convenient and efficient for programming.This paper implements three typical algorithms,Contour-connecting,Marching Cubes and Ray-casting,of medical image 3D visualization using VTK with VC++.Results show that VTK is a powerful tool with many advantages,such as simple operation,fast,and good interaction ability and can be widely used in 3D reconstruction of medical images.

Development of a massage device based on microcontroller in the field of alimentary tract / 生物医学工程学杂志

In this artical is first reported a survey of the progress in research of MEMS technology. Then, the basic structure, features and the principles of a massage device based on microcontroller in the field of alimentary tract are introduced. Special emphasis is laid on the utilization of MSP430F123 microprocessor for producing a kind of period pulse to control the power of massage capsule. In general, the research and development of the massage device in the field of alimentary tract have active support and deep significance to therapy in the clinical and business settings as well as in the development of biomedical engineering and MEMS.

Electrocardiographic signal feature extraction and its instrument development based on continuous wavelet transform / 生物医学工程学杂志

This paper introduces a virtual recording and analysis instrumentation system for recording and identifying electrocardiographic (ECG) signals. The system developed is aimed at constructing a PC-based virtual instrumentation which enables to record. investigate and measure the ECG signal of 12 leads simultaneously and perfectly in order to improve the measuring precision of ECG. Based on the proper feature in time domain of Mexican hat wavelet expressed by positioning and analysis precision for QRS complex, the instrumentation system uses continuous wavelet transform(CWT) and uses the Mexican hat as the wavelet base to measure precisely the characteristic information and generate the precise characteristic parameters of ECG. The analysis of measured ECG signals in hospital demonstrated that even in the condition with serious noise interference, the method presented is still easily to describe the characteristics of ECG on line precisely which makes the instrumentation system valuable in practical application.

Methods applied to muscle fatigue assessment using surface myoelectric signals / 生物医学工程学杂志

Surface myoelectric signal analysis has proved effective for assessing the electrical manifestations of localized muscle fatigue. In the past, the analysis of muscle fatigue was restricted to isometric, constant force contractions due to the limitation of signal processing technique. The development and recent availability of spectral estimation techniques specifically designed for nonstationary signal analysis have made it possible to extend the employment of muscle fatigue assessment to dynamic contractions, thus opening new application fields such as ergonomics rehabilitation and sports medicine. This paper reviews the current study achievements of using surface myoelectric signals in muscle fatigue assessment, particularly in that during dynamic contractions. The conclusions provide theoretical bases for encouraging further studies on the mechanisms of muscle fatigue.

Application of medical signal processing based on theory and method of chaos / 国际生物医学工程杂志

Reviewing the theory of chaos in the field of nonlinear dynamics, this paper summarized theory of chaos and its applications in medical signal processing including electroencephalogram(EEG) signal?electrocardiogram(ECG) signal?electromyogram(EMG) signal, etc. The foreground is reviewed to advance the study and application of nonlinear dynamics theory in biomedical engineering.