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Issue 6 ， 2002
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Design consideration of two-dimensional anti-reflective subwavelength periodic gratings
Abstract：This paper investigates the design of a two-dimensional anti-reflective subwavelength grating, by means of RCWA and EMT, take for example, the square-pillar and columned binary gratings, and pyramidal and coned multi-level gratings, the impact of filling factor and surface profile on the reflectance of a grating are mainly considered. It is shown that surface profile has no effect on the reflectivity when the period is sufficiently small, but the wavelength and the filling factor have an important impact on the diffraction characteristics of the grating. So it is very important to design an anti-reflective grating. The validity of EMT is also investigated in the paper.- 46
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Published：2020-08-12 -
Correcting method for ring artifacts in fan-beam X-ray ICT
Abstract：In a fan-beam X-ray ICT system, the non-uniform response of the detecting system could cause ring artifacts in image reconstruction. In order to mitigate this situation, a class of scan sampling patterns was proposed,which could suppress the non-uniform response and consequently decrease the ring artifacts. A condition, which this class of scan patterns must meet, is discussed. Computer simulation and experimental results show that the reconstruction of image with few ring artifacts, and without any other special disposal, could be generated with a filtered back-projection algorithm using those data sampled by the detecting system with non-uniform response under this kind of scan pattern.Keywords：computed tomography;penetrating radiation tests;ring artifacts;non-uniform response- 46
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- 7
Published：2020-08-12 -
Real-time parallel processing system for remote sensing images based on two DSPs
Abstract：Based on the introduction to the development of real-time processing system for remote-sensing images quickly, this paper analyzes some basic tactics, technology and relative hardware platform of parallel processing. It presents a real-time parallel processing scheme for remote-sensing images based on two DSPs concern with the applied background. At the same time, it also gives a processed output of WEN by the above system. It is concluded that this parallel processing scheme will benefit a huge number of real-time data processing technology in-orbit in the future.Keywords：digital signal processor;remote sensing images;Parallel processing- 49
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Published：2020-08-12 -
Application of wavelet in the spectrum signal processing of microspectrometer
Abstract：This article analyzes the properties of the signal obtained by microspectrometer and studies the influences caused by a wavelet transform on the Gauss peak with a different half-width. The results show that when the decomposition time is 8 by using the Mallat method, the high frequency noise and low frequency background can be reduced by letting the decomposition factors a8, d1 and d2 be zeros when reconstructing the spectrum signal.Keywords：wavelet transform;micro spectrometer;signal processing;spectrum signal- 58
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Published：2020-08-12 -
Research on the system of the construction and virtual display of free-formed surface based on measurement
Abstract：Based on the measurement of free-formed surfaces,a free-formed surface was constructed with the method of NURBS. The virtual graphics of surface model was displayed by the OpenGL technology.A utility construction system of free-formed surfaces was developed in this paper. This system consists of modules of surface simulation, of data input, of interaction modification, of graphics simulation and of surface feature analysis. Some graphics technology used in the system is discussed also.Keywords：free-formed surface;construction;virtual display- 48
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Published：2020-08-12 -
Research on the application of lifting scheme in image lossless compression
Abstract：This paper studies an image lossless compression coding method based on the CDF (m,n)invertible or thogonal wavelet transform of lifting scheme and SPIHT. The experimental results show that the CDF(m,n) transform based on lifting scheme and integer operation, is an integer-integer invertible transform, and that the image lossless compression performance of CDF(2,n) is better than that of Huffman, NinRar,Raw+WinZip, JPEGLS. The compression rate has been improved by 62%,47%,44% and 32%,respectively.Its fast operation speed makes hardware implementation easier.Keywords：lifting scheme;image loss-less compression;CDF(m;n) invertible bi-orthogonal wavelet transform;SPIHT- 37
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Published：2020-08-12 -
Safe-compressing technology of optical theodolite survey information
Abstract：During the course of changing film theodolite survey information into numeral pictures, if the optical survey films are transformed into the bitmap directly, the data will become larger, which will hinder transmission and storage. If the data are compressed, the precision of judging the position of the object will be reduced. This paper adopts picture-handling technology, according to the information recording principles of optical survey film, and the concrete demands of data processing. It designs a new method which can divide the film pictures into different areas, realize direct storage of the areas affecting precision, conduct compression in other areas, and maintain the relative position of different areas to the cross. The goal is for these areas to compose properly when the pictures are restored. The method reduces the data, assures the precision of data, realizes the number of optical survey films and also solves the serious problem of information storage and transmission of optical theodolite survey information.Keywords：picture information;Compression;film;lattice;target- 84
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Published：2020-08-12 -
Study of an image tracking system based on DSP
Abstract：In order to enhance the real-time traits, based on the DSP(TMS320VC5410), a real-time image recognizing and tracking system consisting of four modules is introduced in this paper. The algorithm includes image pre-processing, image segmentation, selecting feature and target tracking, which are explained in turn. At the same time, block diagrams of image tracking are given. Finally, the method is emulated with a computer, and the experimental results are found in accordance with theoretical ones,showing that the system is feasible and effective.Keywords：image tracking;Real-time image processing;image segmentation;DSP;wave gate- 38
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- 10
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Published：2020-08-12 -
High precision 3-D stage for synchrotron radiation beamline engineering
Abstract：This paper briefly introduces the structural principle of a special 3-D stage for synchrotron radiation beamlines. The characteristics include compact structure, heavy load and high precision. It is step motor driven and digitally controlled by software in a PC. A manual operation mode is also reserved.Keywords：synchrotron radiation;beamline;3-D precision stage- 45
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Published：2020-08-12 -
Development of the scanning system for confocal laser scanning fluorescence microscope
Abstract：For adaptation of 3D optical microfabrication and 3D optical data storage, we have developed a stage-scanning system for a confocal laser scanning fluorescence microscope (CLSM) with 138μm x 138μm field of view. The stage employs flexure hinges driven by piezoelectric (PZT) actuators to achieve high positioning accuracy and large scanning area. This paper describes the principle of the stage, and the testing of the static and dynamic properties. The whole system has been testified to work well for confocal laser scanning microscopy.Keywords：confocal microscope;PZT(piezoelectric) actuator;flexure hinge- 50
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- 6
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- 6
Published：2020-08-12 -
Automatic light-adjusting system of CCD video camera
Abstract：With the combination of an electronic shutter and a variable diaphragm in a CCD video camera system, light is adjusted automatically under the control of a single chip microcomputer. In this way,not only is the dynamic scope extended, but also the effective control is made on image displacements produced by dynamic goal. Its maximum image displacement is controlled within 0.0024mm.The methods brought out in this paper have practical use for small television video camera systems.Keywords：image displacement;variable diaphragm;electronic shutter- 48
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Published：2020-08-12 -
Analysis of the transmission efficiency of a two-channel elliptical crystal spectrometer
Abstract：The two-channel elliptical crystal spectrometer (TCECS) is a very important diagnostic instrument for researching inertial confinement fusion controlled by laser. Since spatial resolution is recorded by X-film or X-CCD in one channel, and time resolution is recorded by an X-streak camera in another channel, the spatial and time characteristics can be measured simultaneously. Spectrographic effects will be affected by the transmission efficiency of TCECS, which depends on the reflective ratio of a cylindrical mirror, the integrated diffraction of a crystal, the transmissivity of filter foil, and the spectrographic aperture ratio. The relations between these four influencing factors and wavelength are analyzed theoretically in this paper. The numerical calculations are done by using Matlab 6.1 software. It is indicated that transmission efficiency decreases as X-ray wavelength increases, which is very important to instruct the structural design.Keywords：elliptical crystal spectrometer;transmission efficiency;laser fusion;x-ray diagnosis- 37
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Published：2020-08-12 -
Grazing exit X-ray fluorescence spectrometer
Abstract：The technology of grazing exit X-ray fluorescence is an important tool for the analysis of thin layer characteristics and media surfaces. The principle of analysis of thin layer thickness by this method is described in this paper. A grazing exit X-ray fluorescent spectrometer has been constructed in our lab, which is composed of an exciting source, a sample stage, a monochromator, and a detecting system, collecting data and compressing units. Meanwhile, the result of calibrating this spectrometer by. 55Fe is presented.Keywords：grazing exit X-ray fluorescence;spectrum analysis;thin layer- 56
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Published：2020-08-12 -
Research on the control model of piezoelectric micropositioning actuator
Abstract：Two control models for piezoelectric actuators are introduced from different angles. Firstly, by means of statistic physical analysis, a simple and practical mathematic formula describing the hysteresis of a piezoelectric actuator built by a mathematic modeling method. Then, based on elastic deformation theory, a normalization model of piezoelectric/electrostrictive effect is introduced. Accordingly, the viewpoint that hysteresis can be greatly reduced by polarization control method was proved theoretically. Two experimental systems were designed and two control models tested, respectively. Some experimental results show that the models are effective in decreasing the error arising from nonlinear hysteresis. In this way the micropositioning control accuracy of piezoelectric actuators can be improved. As a result, the research is helpful to realize high precision open loop micropositioning controls based on piezoelectric actuators.Keywords：piezoelectric actuator;control model;hysteresis;polarization intensity- 59
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- 9
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- 12
Published：2020-08-12 -
Micro-nano electromechanical system by bulk silicon micromachining
Abstract：MEMS(Micro ElectroMechanical System)based on semiconductor microfabrication plays im-portant roles for example in the periphery of IT systems.N EMS(Nano Elect roMechanical Sys-tem)contains nano-scale structures.Sop histicated and high performance systems based on the MEMS and the NEMS have been developed.Packaging and elect rical interconnection play an important role in realizing practically applicable systems.- 49
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Published：2020-08-12 -
Design of the image acquisition and wireless transmission branch system of wireless micro robotic endoscope system
Abstract：A new type of short distance micro image acquisition and wireless transmission system was designed. It consists of a micro CMOS image sensor and a UHF micro RF transceiver working in the ISM band. It shows such features as high integration, small size and low power consumption. The paper discusses the feasibility of its application in wireless micro robotic endoscope system , and describes the experiment on the system. The results show that the image is very clear on the monitor.Keywords：micro robot;endoscopes;image acquisition;wireless image transmission- 53
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Published：2020-08-12 -
Research on piezoelectric pump and its development
Abstract：Piezoelectric pump, a new type of piezoelectric actuator, has many potential applications in the future due to its characteristics. Based on public literature, the state of research progress for a piezoelectric pump is surveyed in this paper, including its structure and principle.The performance is described, the application and main trends are also discussed.Keywords：piezoelectric pump;piezoelectric vibrator;research progress- 47
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Published：2020-08-12 -
Study of the technology of modeling and simulation of MEMS
Abstract：This paper analyzes the reason for modeling and simulation of MEMS briefly.There are four difficulties i.e.,microscale effect,fast algorithms of surface force,multiple physics fields coupling algorithms,and development of macromodel of MEMS or microdevice in modeling and simulation of MEMS.Their key technologies are analyzed in detail.Several current methodologies of system-level modeling and simulation of MEMS are introduced. The method of modeling MEMS with the aid of VHDL-AMS is finally proposed.Keywords：MEMs;physic field coupling;Modeling and simulation;macromodel- 34
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Published：2020-08-12 -
Silicon optical MEMS:optical components and sensors
Abstract：Using Micro-Electro-Mechanical System (MEMS)technology,many devices and systems can be miniaturized.M icro pressure sensors and micro accelerometers(air-bag sensor)are examples that are widely commercialized.In the case of optical system,some optical components need to be combined to implement the function desired f or optical processing.A micro-optical bench based on a Si surface and bulk microm achining has been proposed in order to integrate optical components on a Si substrate.- 31
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Published：2020-08-12 -
Explanation of the round interference fringes in the measurement of varied-line-space gratings
Abstract：Varied-line-space gratings can correct aberrations,and they are useful in synchrotron radiation devices and laser inertial confinement fusion devices. In this paper, the line-density of varied-line-space gratings is measured with interferometry. The design of optical alignment is given, and the round interference fringes and their changes are observed in experiments. The prerequisite of round interference fringes is that the density of gratings is monotone, and the density of virtual grating divided by a integer is close to it, but the grooves are curved. The fringes that hyperbolas are predicted.Keywords：varied-line-space grating;line-density;interferometry;round interference fringes- 65
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Published：2020-08-12 -
Intelligent control and application of two-dimensional counting-tracing LDA measurement system
Abstract：Two components of velocity are distinguished and measured by two closed optic-electro-hybrid-feedback loops for counting and tracking in a two-dimensional counting-tracing LDA measurement system. The effective frequencies of optical electric signals are sorted automatically into the corresponding scopes of bandwidth of signal processors, respectively at certain optical frequency shift grades. At the same time, a personal computer supervises the station of the LDA system. The two-dimensional velocities are obtained after a series of disposals of the optical electronic signal frequencies and the optical frequency shifts. In this paper, the application of a two-dimensional counting and tracking LDA measurement system in the flowing measurement of asymmetric sudden wide pipe confirms the successful development of the system.Keywords：LDA(laser Doppler anemometry);intelligent control;frequency shift grade;bandwidth- 49
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- 2
Published：2020-08-12 -
Method for measuring the angle of burst strong flashing object in space
Abstract：The burst strongly flashing event taking place in space such as strong explosion in low air is randomin time and position, and its duration time is very short. The photoelectric measuring method for measuring the angle of a burst strongly flashing object appearing randomly in space is presented. It can complete the measurement of 2D information, the azimuth angle and pitching angle of the center position of a spatial flashing object. The measuring angle principle and basic structure of the measuring angle device are introduced. The critical parts of the device are briefly described. A comparison of measuring the sun’s 2D angle by the measuring angle device and by transit was made, giving the measured results and accuracy analysis. This device has the characteristics of detecting object dynamic range and realizing omnibearing angle measurement, due to being equipped with changeable gain amplifiers and three silicon photoelectric accepters with cylinder surfaces.Keywords：photoelectric detector;2D angle measurement;burst strong flashing event- 50
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Published：2020-08-12 -
Study of the calculation method for accurately adjusting laser-range-finder′s three-optic-axes to parallel to each other
Abstract：For laser range-finders to measure target′s distance accurately and creditably it is important that three-optic-axes are accurately adjusted to be parallel to each other with eccentric object-glass-frame and rings. Because the exercises of optic-axes-adjustment cannot be done with real laser range-finders, the formulate used to imitate real optic-axes-adjustemnt are worked out by using an example in which the object-glass of laser range-finger has an eccentric object-glass-frame and ring to adjust aiming and laser-shooting axes to parallel. First, it is proved that the error of optic-axes-parallelism can be measured with a collimator and a black-photograph. Second, the formulae are given, which are used to calculate the radial displacement of an object-glass' principal point, when aiming and laser-shooting axes are accurately adjusted to parallel with the known error of optic-axes-parallelism and focal distance of object-glass. Finally, knowing the error of optic-axes-parallelism and thinnest-position of eccentric object-glass-frame and ring before optic-axes-adjustment, the formulae are analyzed to give the new thinnest-position of eccentric object-glass-frame and ring for accurately adjusting optic-axes to parallel each other. According to the real handling of optic-axes-adjustment,the principle point of object-glass is moved by rotating eccentric object-glass-frame and ring.Keywords：laser range-finder;optic-axes-parallelism;eccentric object-glass-frame;eccentric ring;imitative simulation- 60
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Published：2020-08-12
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