Virtual instrumentation, virtual oscilloscope, virtual instrumentation technology, virtual instrumentation software, virtual instrumentation development, virtual instrumentation composition
I. Introduction
The current multimedia computers, information superhighway and computer networks are the three important development direction of computer information science. They are interconnected, promote each other, *** with the development, has penetrated into people's daily work, life, learning, entertainment in all aspects, and gradually from the office, laboratory to the family.
Virtual reality is an important application field of multimedia computer, multimedia technology is the technical basis of virtual reality. Virtual reality (Virtual Reality) is the use of multimedia computer technology to generate a realistic visual, auditory, tactile and olfactory simulation of the real environment. Users can interact with this virtual reality using natural human skills, and the result of the user's experience - the reaction of the virtual reality - is similar or identical to the result of the user's experience in the corresponding real reality. The concept of virtual reality includes the following three levels of meaning:
1, virtual reality is the use of computer technology and the generation of realistic entities, people have a real three-dimensional vision of the entity, stereo hearing, texture of the sense of touch and smell.
2, people can have a conversation with virtual reality through natural skills, that is, the human head, eyes, limbs, etc. of the various actions in the virtual reality of the response has a sense of reality.
3, virtual reality technology often have to use some three-dimensional sensing equipment to complete the interactive action, such as helmet-type stereo display, data gloves, data clothes, three-dimensional manipulator and so on.
Virtual reality technology is still in its infancy, but it has been applied in scientific visualization, CAD, aircraft / automotive / surgical, virtual instrumentation and other operational simulation. Already in the aerospace, national defense military, biomedical, education and training, entertainment games, tourism and other fields show a broad application prospects.
Virtual Instrument (Virtual Instrument -- VI) is an important application of virtual reality in the field of instrumentation, has quietly emerged in the international arena. Virtual Instrument is a multimedia computer as the basis for the use of graphical interface programming technology, simulating the actual instrument panel, function and operation, so as to generate a variety of tasks to complete a variety of special instruments.
As a result of the high degree of development of science and technology, resulting in a variety of powerful and increasingly complex instruments continue to emerge, many of which are based on computers, the emergence of the trend of computerized instruments, which is mainly manifested as follows:
1, standardization of the interface between the hardware and the computer
2, the hardware software
3, modularity of the software
4, module control
5, system integration
6, programming graphical
7, scientific computing visualization
8, hardware interface software driven
Because of the continuous development of computer software and hardware technology, coupled with the need for practical applications, so that people's interest in the virtual instrumentation is growing stronger and stronger, and the development of Virtual instrumentation has also become a realistic possibility. The development of virtual instruments mainly stems from the following purposes:
1, to save time and funds for instrument development
2, to fully utilize the functions of computer data processing and analysis
3, the unification of the instrument's user interface
4, to enhance the instrument's functionality and applicability
5, the need to integrate the instrument
6, to make the instrument Easy to expand
Virtual instrumentation is mainly composed of the following parts:
1, interface control library
2, data input, output
3, data processing method library
4, data representation library
5, data storage and management
6, arbitrary signal generation
7, graphical interface Programming environment
Interface control library includes some commonly used instrument panel parts, such as indicators, meters, light-emitting diodes, buttons, dials, dials, sliders, etc. Each control comes with programmable functions and properties.
Data input and output refers to obtaining data from external devices into the computer or outputting data from the computer to control external devices, and it is necessary to establish driver software to communicate with data acquisition boards, serial and parallel ports, as well as other standardized interfaces (IEEE-488, GPIB, RS-232, RS-422, SCSI, VXI, etc.), so as to expand the applicability of the instrument
Scope and application areas.
The Data Processing Methods Library concentrates many data processing methods, such as FFT calculation, filtering, modeling, parameter estimation, etc., and provides programming interfaces for these methods, which can be used to complete various complex tasks by simply combining these methods.
Data representation refers to a certain way to display data and processing results, including digital display, curve display, histograms, scatter plots, two-dimensional graphics, three-dimensional grid graphics, three-dimensional filled graphics, four-dimensional graphics, graphics, and even dynamic graphics or graphics, making the data representation very intuitive and easy to understand.
Data storage and management mainly refers to the provision of data storage format, data query methods, data browsing methods.
Signal generation refers to the need to generate arbitrary signals, some of the standard signals can be used for instrument testing and self-test purposes.
Graphical programming environment refers to the user can be any combination of controls and methods, will be linked into a whole, the formation of specialized instrumentation tools. The use of virtual instruments can be like building blocks as soon as the user to generate the required variety of instruments.
Second, the existing virtual instrumentation and integrated environment examples
1, MATLAB: high-performance numerical computation and data analysis software
MATLAB is the United States by the development of Mathworks high-performance numerical computation and data analysis software. It has become the industry standard for engineering and scientific research, it has a unique user interactive interface, complex numerical calculations, powerful data analysis, flexible scientific graphics, fast calculations, easy to expand and so on, it is the first choice of high-yield and creative scientific research software.
The basic functions of MATLAB are:
※ Matrix operations
※ Matrix decomposition
※ Matrix eigenvalues and eigenvector calculation
※ Signal convolution
※ Spectrum estimation
※ Complex number operations
※ One-dimensional and two-dimensional FFT
※ Filter design and Filtering
※ Curve Fitting
※ Triple Spline Fitting
※ Bessel Functions
※ Nonlinear Optimization
※ Linear Equation Solving
※ Differential Equations
MATLAB includes toolboxes such as:
※ Digital Signal Processing Toolbox
※ Control System Design Toolbox
※ System Identification Toolbox
※ Self-Expansion Toolbox
MATLAB includes the following plotting functions:
※ Histogram
※ Scatter Plot
※ Curve Plot
※ Three-dimensional Grid Plot
※ Three-dimensional Filled Plot
※ Contour Plot
※ Polar graphs
※ X-Y plots
※ Image display
2. DADiSP: Data Analysis and Graphics Software for Scientists and Engineers
DADiSP software is developed by DSP Development Corporation in the United States.
DADiSP software is developed by DSP Development Corporation in the United States, and is mainly used as a data analysis and graphical display tool for scientists and engineers. It includes the following functions:
※ Matrix operations
※ Eigenvector and eigenvalue computation
※ One-dimensional, two-dimensional FFT and convolution
※ Two-dimensional, three-dimensional, four-dimensional graphic display
※ Medical image processing
※ Satellite remote sensing image processing
※ Seismic signal processing
※ Statistical analysis and processing
※ Experimental design
※ Hypothesis testing
※ Filter design
※ Sonar Radar Signal Processing
※ Speech and Communication Signal Processing
※ Vibration Analysis
3. MP100: Medical Signal Acquisition and Processing System
MP100 is a medical signal acquisition and processing system developed by BIOPAC System, Inc. BIOPAC System developed by the United States medical signal acquisition and processing system, which runs with AcqKnowledge software, providing a flexible, easy-to-use modular system that allows you to complete the data acquisition and analysis tasks as you wish. AcqKnowledge is a powerful, very flexible software package, which uses drop-down menus and dialog boxes, without having to learn another programming language. AcqKnowledge is a powerful and flexible software package that uses drop-down menus and dialog boxes to design complex data acquisition, simulation, triggering and analysis systems without the need to learn a separate programming language. The main functions include real-time data recording, analysis and filtering, off-line data analysis and processing, and various graphical representations of data. The system can be linked with the virtual instrument LabVIEW to provide a visual graphical programming environment. Its main application areas are:
※ Exercise physiology
※ EMG signal recording
※ ECG recording and analysis
※ EEG recording and analysis
※ Evoked potentials recording and analysis
※ Ophthalmoplegia electrograms and ocular motility analysis
※ Nerve conduction analysis
※ Mental Physiology
※ Pharmacology
※ Telemetry monitoring
4, LabVIEW: Graphical Programming Virtual Instrument
LabVIEW is a graphical programming virtual instrument system developed by National Instrument Corporation. Mainly includes data acquisition, control, data points, data representation and other functions, it provides a novel programming method, that is, the graphical assembly of software modules to generate a dedicated instrument.LabVIEW by the panel, process block diagram, icon / connector composition, where the panel is the user interface, process block diagram is the source code of the virtual instrument, the icon / connector is the call interface (Calling) Interfaces.) Flow block diagram includes input/output (I/O) components, computing components and sub-VI components, which are represented by icons and data flow lines; I/O components communicate directly with the data acquisition board, GPIB board, or other external physical instruments; computing components to complete the mathematical or other operations and operations; sub-VI components to call other virtual instruments.
5, LabWINDOWS/CVI: C language programming of the virtual instrument
LabWINDOWS function is similar to LabVIEW, and developed by the same company, the difference is that it can be used in C language programming of virtual instruments.
6, LabLinc V: modular virtual instrument system
LabLinc V by the U.S. COULBOURN INSTRUMENTS developed modular virtual instrument system, which consists of the basic unit, signal acquisition and processing, control and other modules, mainly used in physiology, biomedicine and biomechanics, and other fields of data acquisition, real-time display and process control, etc.
7, HyperSignal: visual signal processing system design
HyperSignal by the U.S. Hyperception developed by the company's visual signal processing system design software, which makes the process of signal processing system design visualization, while making the signal processing results visualization.
8, Model900: flexible data acquisition and waveform generation system
Model900 developed by the U.S. Applied Signal Technology, Inc. to provide high-speed, high-capacity data acquisition, waveform generation and other functions, the use of virtual instrumentation environment in order to save development time and money.
9, DASP: large-capacity data acquisition and processing analysis software
DASP developed by the Oriental Institute of Vibration and Noise Technology, mainly used for scientific experiments data recording and analysis, multi-functional signal acquisition and analysis, automation of data acquisition, display, readings, calculations, analysis, storage, printing, plotting and so on.
10, LabDoc: integrated instrumentation software package
LabDoc developed by Japan's CONTEC Electronic Technology Co., Ltd. which has a variety of measurement instrumentation functions, through the graphical user interface and online help, can provide easy to operate the instrument screen. It can be applied to laboratory, production line inspection, education and training, etc. The main test functions are:
※ Digital Filtering
※ Pulse Generation
※ Function Generation
※ Waveform Generation
※ Tuned Signal Generation
※ FFT Analysis
※ Frequency Counter
Above we Listed ten currently more popular virtual instruments and integrated environment systems, including the United States in this area of work is the most outstanding, while our country in this area is just starting, have not yet seen the complete virtual instrumentation system. By the above examples can be seen, virtual instruments have the following characteristics:
※ involves more esoteric numerical calculation methods
※ integrated signal processing and process control algorithms
※ software and hardware modules are independent of each other
※ with the secondary development of an integrated programming environment
※ multidisciplinary intersection, penetration of the product
< p>Three, virtual medical signal processing instrumentsThe range of medical signals is very wide, in which the common medical signals are electrocardiography, electroencephalogram, evoked potentials, electromyography, ophthalmology, gastroenterology, nerve impulse potentials, blood pressure, pulse wave, respiratory wave, temperature and other signals, which are characterized by various
differences in characteristics, and their respective frequency bands, amplitude ranges, sources of interference, and so on, thus making the processing of medical signals become very complex. The signal processing of medical signals has become very complicated.
Whatever the medical signal instrumentation, almost all involved in signal amplification, acquisition, analysis, processing, filtering and other **** the same task, while different signals have their own special processing methods, the organic combination of these **** the same sex and specificity, the formation of an integrated environment is the basis of virtual instrumentation.
Because of the need for multi-parameter clinical monitoring and comprehensive diagnosis, medical signal acquisition and processing instruments show a trend of integration, people from the development of a single function of the medical signal instrument to the development of multi-functional integrated instrument, however, this integration is not a single-function instrument of the stacked combinations, but from the different single-function instrument to find out the **** the same point and the different points, the formation of software and hardware modules, will be the computerization of medical signal processing instruments, constituting a medical signal processing instruments, and the computerization of medical signal processing instruments. Signal processing instrument computerization, constitute the medical signal processing instrument development environment, that is, virtual instrumentation.
Virtual medical signal processing instruments is a promising field, many medical instrumentation companies are optimistic about the prospects of this market, investing a lot of human, material and financial resources to engage in research and development in this area, the previously mentioned MP100 medical data acquisition system and LabLinc V modular virtual instrument is one of the outstanding representatives.
Virtual medical signal processing instrument is the development and production of a variety of medical signal instrumentation tools. For developers, it can be like building blocks as soon as the generation of specialized instruments, saving a lot of development time and money; for the user, you can spend less money, buy more instruments. Virtual medical signal processing instruments for the development of integrated multifunctional instruments to lay the foundation, and can be the latest research results as soon as possible to apply to the instrument. In addition, virtual medical signal processing instruments can be used for the research of unknown signals and unknown characteristics of signals, to achieve the purpose of fast results, more results. In fact, the virtual medical signal processing instruments also on the current telemedicine, medical e-books and other popular research areas will play a role in promoting the role.
Four, virtual instrumentation related technologies
1, numerical calculations
In the virtual instrument, the need to provide flexible data processing methods, these methods can be based on the actual needs of the user through the programming to achieve, in order to simplify the complexity of the programming and to save a lot of time in the development of a virtual instrument should be as much as possible to provide a variety of numerical calculations program, these numerical calculations are mainly in the following areas. These numerical calculations are mainly in the following areas:
※ Matrix operations (addition, subtraction, multiplication, inverse, transpose)
※ Eigenvalues and eigenvectors calculated
※ Matrix decomposition
※ Unitary, binary interpolation
※ Numerical integration and differentiation
※ Linear algebraic equations
※ Nonlinear equations solved
※ Fitting and Approximation
※ Special Functions
※ Regression and Statistics
2, Digital Signal Processing
In the complex instrumentation, digital signal processing occupies an important position, and thus it is necessary to integrate a variety of digital signal processing methods in the virtual instrumentation, the digital signal processing methods can be divided into several major categories:
※ Signal Signal pre-processing
※ Filter design and filtering
※ Classical spectral estimation
※ Modern spectral estimation
※ Correlation and convolution
※ Discrete transform
※ Digital feature calculation
※ Common signal generation
※ Signal modeling
※ Data compression
3 Computer graphics, graphics
Graphics and images are intuitive representations of a large amount of data in complex instruments, such as static and dynamic electroencephalograms, surface temperature distribution maps, electromagnetic field distribution maps, etc., which can be converted from the original very abstract data into an easy to understand intuitive representations; in addition, the data and its analytical results, people are accustomed to curves, histograms, three-dimensional graphs, contour maps, etc., to represent. etc. to represent. So in the virtual instrument, the establishment of these data graphics, image representation module is very necessary.
4, scientific computing visualization
Mentioned earlier, the complexity of a large number of data graphics, graphical representation of the virtual instrument is very important, however, by the data to the graphical mapping is not a simple matter, which is the development of recent years, the visualization of scientific computing research topics.
The fundamental purpose of scientific computing visualization is to convert a large amount of data obtained from experiments or numerical calculations into computer images that can be perceived by human vision. The use of images to a large number of abstract data organically organized together, so as to image, vividly show the content of the data expressed and their interrelationships, to help people directly grasp the complexity of the overall situation, better discover and understand the laws, and get rid of the complexity of a large number of abstract data confusion. The introduction of scientific computing visualization in the virtual instrument will show people the infinite charm of the instrument, so that the instrument has the ability to handle and analyze a large amount of complex data.
5, object-oriented visualization programming
Virtual instrumentation is an integrated programming environment, with which people can quickly generate their own needs of complex instruments. So the virtual instrument should be both programmable and easy to operate, so people introduce object-oriented visual graphical programming techniques into the virtual instrument. In the virtual instrument integrated many powerful components, these components with intuitive computer graphics, each component has the corresponding controllable attributes, operations and functions, people only need to lay out these components in the computer screen, set up the appropriate attributes, as well as its connection with other parts of the relationship between the instrument can be generated to constitute the corresponding function.
V. Summary
Virtual instrumentation is the current domestic and foreign just started the field of research, many high-tech companies and research institutes are optimistic about the prospects for this market application, have invested a lot of manpower, material and financial resources to step up the development and research. Virtual instrumentation is an important application of multimedia computers, multidisciplinary cross, the product of penetration, which is concentrated in many high, precise, pointed science and technology. Virtual instruments are not instruments but higher than the instrument, it greatly shortens the development cycle of new instruments, saving the cost of instrument development, it is not only the development of instruments, but also a powerful means of scientific research. Virtual instrument is the product of instrument computerization, is the basis of integrated instrumentation, is a revolution in the instrument industry, its development and development has far-reaching significance.