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Issue 10 ， 2008
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A new design of three-focus single objective lens used in DVD pick-up head
Abstract：In order to meet the compatibility between CD, DVD and HD-DVD disc, a single objective lens with a binary diffractive surface and an aspheric surface is designed. The lens is used for three wavelengths which are 780nm, 650nm and 405nm, and the numerical apertures are 0.45, 0.60 and 0.65, respectively. The binary diffractive surface is divided into two concentric radial zones. According to the harmonic diffraction theory, each region has a different diffraction order depending on the wavelength. The structure and working principle of the three-focus objective lens are presented .The design principle of the aspheric object lens, the parameter of the binary diffractive surface and spherical surface, and the metewand of the aspheric objective lens are described in detail. The use of zemax to simulate the lens is introduced and the simulation results show that the objective lens reaches the practical requirement.Keywords：optical pick-up;objective lens;three-focus;zemax- 42
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Published：2020-08-13 -
Temperature distribution simulation of the optical magnetic hybrid recording media with super-resolution near-field structure
Abstract：In order to further reduce the recorded bit size of optical-magnetic hybrid recording, Super-resolution near-field structure (Super-RENS) thin film model, near-field optics model and temperature field model were built for optical-magnetic hybrid recording media. Finite element method was used to simulate the temperature distribution of the recording layer of Super-RENS hybrid recording media. The layer structure of hybrid recording media was C(2nm)/Sb(10nm)/SiN(10nm)/Co75Cr15Pt10(30nm). When the writing temperature was 550K, the temperature writable area of hybrid recording media increased with the laser power. When laser power increased from 3.9mw to 6.9mw, the sizes of temperature writable area in both vertical and horizontal directions doubled and the areal recording density decreased to a quarter.Keywords：super resolution;near field;optical-magnetic hybrid recording media;temperature distribution- 41
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Published：2020-08-13 -
Liquid crystal based retina adaptive optics imaging system with the laser
Abstract：a model eye adaptive optics imaging system based on liquid crystal was demonstrated in this paper. The LCOS and HASO32 were used as wave-front corrector and wave-front detector respectively. The wave-front aberration detected was calculated and converted into voltage value. The computer put it on the LCOS to corrected the aberration. The optical performance of the model eye was improved by correcting the optical aberration of its own. After correction the wave-front error was reduced from 1.92m peak-to-valley to 0.048m peak-to-valley. The optical system diffraction limit was approached after correction of 70lp/mm.- 55
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Published：2020-08-13 -
An Achromatic Method based on Hybrid Refractive-Diffractive Principle for the Optical Imaging Objective with Long Focal Depth
Abstract：For the purpose of achromatic aberration and focal depth extension, an achromatic method in visible band is presented for the optical imaging objective with long focal depth in this works, which is based on the refractive-diffractive hybrid objective. By analyzing the formation of the logarithmic phase, the dispersion of the element with long focal depth is discussed. According to the refractive-diffractive hybrid achromatic principle, the phase distributive of the refractive and diffractive elements was restructured. In the novel objective system, the diffractive elements were employed for the focal depth extension and the achromatic focal power. Compared with traditional objective system, Simulation results showed that the on-axis intensity distribution of the achromatic hybrid refractive-diffractive objective based on novel phase relationship is unaltered in central wavelength λd(587nm), and they are the coincidence in achromatic wavelength λF(486nm), λc(656nm).Keywords：refractive-diffractive optics;optical imaging objective with long focal depth;achromatic method;uniform-intensity- 65
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Published：2020-08-13 -
Designing of the 3D EPIS System by optical fiber
Abstract：In order to realize the non-contact measurement of three dimensional deformation of the tested object, the three dimensional deformation measurement system based on electronic speckle pattern interferometry(ESPI) is designed. In this designed system, the one-to-five type fiber is one part to dispart and propagate light., which making the designed measurement system sample. Combining ESPI and the phase-shifting technique to get the quantitative deformation measurement. And PZT is used to shift the phase, the deformation results are calculated by “4+1” phase-shifting algorithm. The designed system can realize the in-plane and out-plane deformation measurement respectively, further, three dimensional deformation measurement of the tested object can be gotten. The experimental results of the in-plane, out-plane and three dimensional deformation for the wood block with defect and the steel plate with stress validate the designed system.- 25
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Published：2020-08-13 -
Quantitative Forecasting of Precision of Intersection Measure
Abstract：In order to resovle Quantitative Forecasting of Precision of Intersection Measure when the simple error theodolite is knowed. Beginning with the basic multi-sensor triangulation equations used to estimate a 3D target position, error propagation equations are derived by taking the appropriate partial derivatives with respect to various measurement errors. Next the concept of Gaussian measurement error is introduced and used to relate the standard deviation of various measurement errors to the standard deviation of the target 3D position estimate. Plots of the various error propagation coefficients are generated. The results indicate that the intersection errors is the smallest when the intersection angle is 90°，and when 20°-60°，the error changing is not obvious.The last is a set of equations and graphs useful for designing a two-sensor system to meet a required accuracy specification.Keywords：Triangulation- 63
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Published：2020-08-13 -
Measurements Refractive Index of Aerosol Particles in Xiamen
Abstract：The refractive index is important for studying aerosol. A new method is proposed to retrieve the refractive index of aerosol by using Aethalometre、Optical particle counter and Integrating Nephelometer.The absorption coefficient and scattering coefficient are measured with a Aethalometre and Integrating Nephelometer. and at the same time, the number density distribution of aerosol particle is measured by Optical particle counter with nominated radii, Mie theory is used to set up the relationship among the refractive index 、size distribution、absorption coefficient and scattering coefficients. Then, a curve of absorption coefficient and scattering coefficient can be calculated with different refractive index. Actual value of refractive index can be decided with the measurement absorption coefficient and scattering coefficient by Aethalometre and Integrating Nephelometer. The comparisons with other instruments show that this method is satisfactory. The character of refractive indices of aerosol particles retrieved in Xiamen with the proposed method are discussed at last..- 33
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Published：2020-08-13 -
Design of a Novel Multi-channel Optical Rotary Joint by Using of De-rotating Prism
Abstract：Objective: Optical fiber communications technology has greatly improved the information transmission speed and capacity, and it has become a major information transmission technology. Fiber optical rotary joint technologies could be used in some occasion to transmit signals continuously from rotary platform to stationary platform. Fiber optic rotary joint with large transmission capacity, small size, light weight and good performance in electromagnetic compatibility has been widely studied and applied. Method: A novel multi-channel optical rotary joint using square-cylinder de-rotating prism was proposed based on analyzing principle of the de-rotating prism multi-channel Fiber optical rotary joint. Result: The results of analysis of coupling characteristic of this optical rotary joint indicate that its insert loss mainly comes from the mechanical inaccuracy and the spherical aberration of de-rotating prism. The insert loss is below 2.0 dB according to the results of numerical simulation. Conclusion: This entirely meets the requirement of military equipment such as radar system, and has widespread application prospect.Keywords：Rotary joint;de-rotating prism;GRIN lens;collimating system- 43
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Published：2020-08-13 -
Use self-made TIS scatterometer to evaluate the performance of the surface modification of silicon carbide mirror
Abstract：A TIS scatterometer is manufactured based on the theory of total integrated scattering for the engineering needs and it is used to evaluate the performance of the surface modification of silicon carbide mirror.The merits of this device include that the operation on it is very simple , convenient and rapid.It needn’t to touch the surface of the sample in the testing process thus there is no risk to destroy it.The analysis of the testing datas and the comparation to Lambda 900 spectrometer show that it is reasonable and effective to evaluate the performance of the surface modification by means of scattering characteristic and the testing results of the TIS scatterometer is exact and reliable.Keywords：TIS;scatterometer;SiC mirror;surface modification- 32
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Published：2020-08-13 -
A new method to simulate and analyze the superposition compound eye simply
Abstract：The structure of the superposition compound eye is relatively complicated, therefore the si mulation and analysis process are very difficult, and this has been the bottleneck problem in the artificial superposition compound eye development. In this paper, a new method to simulate and analyze the superposition compound eye simply and easily was put forward. The effect of the different ommatidial on the power received by the rhabdom can be analyzed by analyzing the effect of the different rays focused by one ommatidial on the power received by the different rhabdoms. In this way, a great deal of ommatidia’s 3D coordinators calculation can be avoided, so the modeling process is become much simpler. A simulation of an superposition compound eye was completed by this method in the ZEMAX software. From the result, it has been proved that the simulation and analysis completed by this method is accurate.Keywords：superposition compound eye;sensitivity;ZEMAX software- 50
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Published：2020-08-13 -
Precision measurement of TDICCD interleaving assembly
Abstract：Focal plane is one of the most important components of remote sensing camera, and we could obtain a long focal plane by means of interleaving assembly of TDICCD. As to the longer TDICCD focal plane, it is difficult for us to obtain precise measuring results through the conventional method. Monitoring the pixels of TDICCD directly, using an air rails (linearity less than 2 μ m / m) that carries microscopic system, get the space position of the pixels. Measuring 600 mm long focal plane, attain the accurate test results whose error is less than 3 μ m. According to the imaging test of remote sensing camera on ground, by the research and analysis of the image, the precision reflected from the image matches as that obtained from the accurate measurement. So it is proved that this method is precise and feasible and could achieve high-precision measurement of the long focal plane.Keywords：applied optics;interleaving assembly;Focal plane;precision measurement- 52
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Published：2020-08-13 -
Radiation Effects and Radiation Harden of Flash Memory for space optical remote sensor
Abstract：Flash devices for a space optical remote sensor are selected as researching samples. Start with the circuit structure of the devices, the total dose effects(TDEs) and invalid mechanism in space are analysed. It is considered that the ionization effects make the threshold voltage of transistors in devices drift. The continuous drifting arouses the control circuit and memory cells invalid. And the control circuit becomes invalid first than the memory cells. With the TDEs, the accumulation of trap charge makes the static current and dynamic current increase. According to the radiation experiment using 60Co γ source, the invalidation threshold of these devices is between 15k Rad(si) and 20k Rad(si). The analyse to TDEs and invalid mechanism of Flash devices is also proved by the experiment results. Finally, some radiation harden methods are put forward such as N modular redundancy, check coding and cold backup.- 36
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Published：2020-08-13 -
The Waveband Selection for Optical Remote Sensor Designed for Detecting Marine Target
Abstract：During the mission of developing a remote sensor, the selection of waveband is one of the most important factors for sounding and identifying a target. Aiming at the application like detecting marine target from large area background, major factors which will restrict target detecting were analyzed. As an instance, in case of abyssalpelagic ship target, the SNR and contrasts between target and background at different wavebands within visible/near infrared region were calculated by using atmospheric radiative transfer code—MODTRAN 4.0, and whereupon it was concluded that for wide waveband remote sensor aiming at marine target detecting, the best waveband is from 0.5m to 0.9m..Keywords：Marine remote sensing;Target detection;waveband selection;SNR- 32
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Published：2020-08-13 -
Low Noise Video Processing Technique
Abstract：This paper develops the noise model of TDI-CCD camera system, analyses generated mechanism of read reset noise of TDI-CCD video signal and the principle of the CDS (Correlated Double Sampling) technique. Every part of the video processing circuit is analyzed and the design methods were presented. The scientific grade TDI-CCD camera is designed according to them. Results show that the designed circuit can effectively suppress dark current noise 、reset noise and 1/f noise．The output S/N (signal to noise ratio) of TDI-CCD camera can exceed 50 dB when the data rate is 50MHz.Keywords：TDI-CCD;low noise;CDS;video processing- 46
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Published：2020-08-13 -
Research and applications of forward kinematics of six-bar parallel mechanism in synchrotron radiation beam-line
Abstract：Six-bar parallel mechanism is widely used in synchrotron radiation beam-line now. But its six-dimensional adjustment is difficult and inefficient because of lacking theoretical direction. Based on the inverse kinematics, forward kinematics of six-bar parallel mechanism is obtained by trust region method for nonlinear optimization. The corresponding program with MATLAB language is also given. The result shows that trust region method is an effective way to study forward kinematics, and the program is stable, reliable and fast. This method has small errors with linear precision of 10-12mm and rotational precision of 10-15deg. Using differential snail adjustment, monochromator box’s attitude can reach a linear resolution of 5μm and a rotational resolution of 3". It completely satisfies the practical requirements.Keywords：synchrotron radiation;monochromator;six-bar parallel mechanism;forward kinematics;trust region method- 30
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Published：2020-08-13 -
Simulation for Vertical Monochromator of Neutron Diffraction Residual Stress Instrument
Abstract：This paper has reported a Monte Carlo simulation for vertical focusing monochromator Ge (511) of neutron diffraction residual stress instrument. The factors which will influence performance of instrument, such as the height of the monochromator and the angle between two crystals, have been investigated. Also the two conditions with the vertical focusing monochromator and with the flat monochromator which will affect the flux of sample table have been compared. At last the resolution of instrument is considered.Keywords：neutron diffraction;residual stress instrument;monochromator;vertical focusing;neutron intensity- 38
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Published：2020-08-13 -
Compact high-precision soft X-ray and extreme ultraviolet reflectometer
Abstract：A compact soft x-ray and extreme ultraviolet （EUV）reflectometer system using a laser produced-plasma (LPP) light source with liquid-jet target have been built based on the requirement on high-precision reflectance measurement of multilayer mirrors for use in an EUV imager which is a payload of CHANGE plan. This reflectometer is mainly composed of a LPP light source, Mcpherson 247 type grazing-incidence monochromator with moving exit slit and correlative data collection system. The monochromator have 1-125nm wavelength range and less than 0.08nm spectral resolution. In comparison with metal target LPP source, the usage of debris-free liquid-jet target LPP source avoid destroying optical elements near the light source, while the use of grazing-incidence monochromator with moving exit slit improve both wavelength range and spectral resolution. At the same time the measurement results of Mo/Si multilayer coatings reflectance with central wavelength 13.5nm and 30.4nm also are given. The curves of reflectance Vs. wavelength of Mo/Si multilayer coatings show the repeatability of the reflectance measurement is better than ±0.5%.Keywords：soft X-ray and extreme ultraviolet reflectometer;multilayer coating;liquid-target LPP source- 49
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Published：2020-08-13 -
Mid-wavelength infrared dual field-of-view optical system
Abstract：For cool 320×240 detector with staring focal plane array, a middle infrared continuous zoom optical system is presented. The optical system,which is composed of 8 lens, adopts the optical structure form of secondary imaging and front group lens moving along the optical axis. Based on practical application requirement and feature parameters of the detector, the optical design parameters are given. Then used zoom system principle and optical design software the schematic diagram, modulation transfer function (MTF) curver, spot diagram, and root mean square value (RMS) of the spot diameter are investigated. The parameters of the system is 1.96 f/number, 100% cold shield efficiency, 180mm/60mm effective focal length (EFL), 3-5 μm spectrum region, and 75% transmission. The optical system is analyzed from two mode of narrow field of view (NFOV) and wide field of view (WFOV). It has the advantages of simple structure, high image quality. And moreover, only one aspheric surface is adopted in the system, so the system has the benefits of low price and easy to machining and adjust.Keywords：infrared optical system;dual field-of-view;optical design- 54
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Published：2020-08-13 -
Investigation on ultrasonic levitative support to high speed axis in fly wheel
Abstract：The rotate speed has an effect on the storage rate and working performance of the fly wheel storage system, traditional bear has great friction coefficient and low limit speed, all of these restrict the development and application of fly wheel storage system, the ideal resolution is levitation support technology. Ultrasonic levitative support technology is using the high frequency vibration of ultrasonic transducer to form the interstice between the axis and vibrating surface, reduce fraction coefficient, decrease friction resistance moment, and increase the rotate speed. According to the testing equipment, the interstice of ultrasonic levitative support has been measured; the axis should be levitative supported when interstice lager than the summation roughness of scratch surfaces, the average interstice is up to from 12.49 to 52.97 micrometer under the condition of voltage is of 100 to 220 volt and frequency is of 21.34 kilo hertz.Keywords：fly wheel storage system;ultrasonic levitative bear;levitative technology;microsatellite- 35
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Published：2020-08-13 -
Design of laser guided measuring robot motion system
Abstract：Laser tracker system (LTS) is one of the latest portable three dimensional large size coordinate measuring machines (CMMs). It measures 3D coordinates with laser beam by following a spherical mounted retro-reflector (SMR) with the advantages of broad range, high speed and high accuracy. However, the current inspecting task of LTS is performed manually to move SMR along the different position on the surface of a given part and measured with complex course, low efficiency and the trial-and-error approach, which cause the deformation of measured part and seriously affect the measurement accuracy. In order to perform LTS more efficiently and automatically, a new laser tracking measurement theory of “laser beam moving and SMR tracking” is proposed. The laser guided measurement robot (LGMR) technology is studied and a miniature wheel-armed LGMR system is developed based on this theory which can move on the horizontal and vertical surface of measured part. The LGMR system combines the merits of wheeled mechanism, armed mechanism and vacuum-sorbs mechanism, and possesses many advantages, such as less weight, small volume, simplicity structure and quickly response. LGMR can changes the measuring modes according different characteristics of parts, it moves on the horizontal surface with high speed and remote distance using wheeled system, and climbs flexibly on the smooth inclined surfaces using crawling armed system. The moving characters of LGMR are analyzed in detail. The Faro SI laser tracker and Hexagon Globle9128 coordinate measuring machine (CMM) are used to test the performance of LGMR, the experimental results show that the LGMR can track laser beam automatically and effectively measure on the surfaces of given part.Keywords：laser guided;measuring robot;design;moving character- 40
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Published：2020-08-13 -
Study on Modifying Inertia Weight in PSO for Finding the Threshold of Otsu Rule
Abstract：In order to find the threshold of Otsu rule rapidly, a modifying strategy to the inertia weight in particle swarm optimization(PSO)is introduced. This makes the inertia weight being updated by the distance between the best position of the individual particle and the globally best position. With the reduction of the distance between the globally best position and the individual best position, the inertia weight of the individual particle would be reduced, vice versa. The comparison results with other methods indicate that this algorithm has less computational work and a fast convergence.Keywords：Otsu rule;Particle Swarm Optimization(PSO);Inertia weight updating- 38
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Published：2020-08-13 -
An adaptive non-contact submicroliter liquid dispensing system
Abstract：In the protein crystallization, thousands of reagents with different viscosities need to be transferred or dispensed. Most of the commercial automated liquid dispensing systems need to be calibrated through experiment to accurately dispense liquids when the reagent viscosity changes, which is time consuming and less accurate. In this paper, an automated adaptive non contact liquid handling system was developed, which could dispense submicroliter reagent without touching off. The noncontact reagent dispensing is accomplished by rapidly opening and closing the solenoid valve while applying fluid pressure to it and the volume modulation is possible by altering the opening time of the valve and the flow rate. The system combines the advantages of non-contact solenoid-based technology with the robustness and flexibility of traditional liquid handlers. The novel flow-through design and the integration of high-speed flow sensor enable robust, repetitive, flexible, low-volume dispensing of samples with different properties. This paper focuses on the system construction, dispense process analyses and control. Finally, experiments results are presented with different dispensing volumes, coefficient of variance (CV) has been shown to be below 3% at 1μl and approach 8% at 50 nl.Keywords：Nanoliter liquid dispensing;MEMS;flow sensor- 46
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Published：2020-08-13 -
Acceleration and Deceleration Control of Laser Processing Machine Tools for Engine Connecting rod Fracture Splitting Notch
Abstract：The objective of Laser Processing Machine Tools for Engine Connecting Rod Fracture Splitting Notch (the laser notching machine) is to cut notch in the inner surface of big-end hole of connecting rod at high speed and with high precision. In programming NC of this laser notching machine, in order to avoid the overcut as well as the remains resulted because of the importing of M function, this thesis put forward a look-ahead means to deal with the acceleration/deceleration of this laser notching machine. In addition, this thesis presents the new NC processing program by combining the result with the former program. Finally, fracture split the connecting rod after the laser cut the notch. Check the result with specific tool and it shows that the right and left parts of the splitting notch are symmetrical in the depths(the difference between the depths of the two sides is ±0.025mm) for all types of connecting rods. What’s more, there is no deviation of the center, the overcut or remains. This illustrates that this means greatly improves the stability and precision of the laser notching machine.Keywords：connecting rod;fracture splitting notch;laser;acceleration/deceleration;speed pretreatment- 28
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Published：2020-08-13 -
Modification of silicon absorbing coefficient in laser bending experiment
Abstract：Considering thermal factors changing with temperature, the laser bending experiments and simulation were conducted based on the material of silicon. The laser bending simulation program is edited by APDL and started from a single point of the temperature field, temperature variation on action point in cycle time were obtained；NiCr/NiSi alloy thin film thermocouple was applied to measure temperature distribution of single-pulse action process. Comparing the temperature field simulation results with thermocouple measurements results, absorption factor of silicon was modified into synthetic coefficient. Finite element analysis software was used in the simulation of pulse laser bending of silicon. The results of the simulation and experiments indicate that the simulation program was effective. The outcomes provided theoretical and experimental foundation for laser bending of silicon.Keywords：laser bending;absorbing coefficient;pulsed laser;silicon wafer- 42
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Published：2020-08-13 -
Optic-fiber evanescent wave sensor based on new type D-shaped fiber
Abstract：An optic-fiber evanescent wave sensor based on new type D-shaped fiber is designed. By letting the energy of the evanescent wave field and the analyte interact with each other directly and increasing the effective area of the sensing fiber, the sensitivity of the sensor is improved greatly. Compared with the sensors fabricated by B.Culshaw and G.Stewart, the new sensor is found to be three orders of magnitude more sensitive. Per equal length, the sensor’s sensitivity is about 1.2 times of the open-path cell sensing. Also we propose a new, low-cost and efficient method fabricating D-shaped fiber based on machine grinding.Keywords：D-shaped fiber;optic-fiber evanescent wave sensor;high sensitivity- 54
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Published：2020-08-13 -
Strapdown seeker system model and simulation analyze
Abstract：By applying mechanics and space flight principle，aim at the strapdown optical seeker special characteristics，to set up the pitch and azimuth two axes platform optical seeker model of the flight system． Then we described the coordinate system of the line of sight in the space and its transformation, the stability of the centerline of seeker sensor beam in the vehicle body disturbance and the algorithms principle of navigation flight were studied．Check up the influence of vehicle aero elasticity to the seeker works. Based on this model，the computer simulation of the missile system flight is done，the result show that the image have a top dithering line of sight bias about 0.5°on the condition of vehicle aero elasticity disturbance, it is easy to lose the target and unable to track. If we can track the target on-time, when filtered the line of sight rate ,the output of guidance single and the miss distance are almost consistent with and without the aero elasticity disturbance ,and the miss distance approximately 1 meter.Keywords：strapdown;model of seeker;system principle;simulation- 41
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Published：2020-08-13 -
Hardware-in-the-loop simulation for aircraft based on rapid prototype
Abstract：A real-time flight simulation system of large-scale hardware-in-closed-loop is constructed with rapid prototyping technology. It is composed of the flight-dynamics simulation subsystem, flight control subsystem, and visual simulation subsystem, etc. They are connected through unified high-speed optical network. Based on the principle of hierarchy and modularity, the mathematical model for aircraft flight dynamics simulation was established in Matlab/Simulink. The hardware-in-closed-loop simulation model was developed from the mathematical model, used corresponding driver module. Finally, the mathematical and hardware-in-closed-loop simulation were carried out with the example aircraft’s data. Compared with flight experiment, the relative error of range is 2.3％, and the relative error of maximal altitude is 0.85％. The simulation results validate the rationality and validity of modeling theories and methods.Keywords：rapid prototyping;HIL simulation;RTW;VxWorks- 25
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Published：2020-08-13 -
Realization of attitude algorithm module in strapdown inertial guidance system
Abstract：A method to realize attitude algorithm module in strapdown inertial guidance is presented. Based on the digital signal processor and quaternions, the attitude algorithm module in strapdown inertial guidance is designed. Firstly, the principle of trapdown inertial guidance, the attitude algorithm and the numerical method is introduced. The circuit and software of attitude algorithm is designed. The test result shows, when the increment is less than 5°, the relative error is less than 0.005286％ with 4 order Runge—Kutta; the algorithm time is less than 36µs with TMS320C6713B. It can meet the demands of trapdown inertial guidance.Keywords：Quaternions;Strapdown System;Inertial Guidance;Attitude algorithm- 66
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Published：2020-08-13 -
AFM based femto-second laser nanofabrication of PMMA
Abstract：A new nano-process technique beyond conventional optical lithography was introduced. As the main mechanisms, field enhancement effect was discussed. Using Finite Difference Time Domain method(FDTD), the near-field optical distribution of metallic tips was simulated. Nanofabrication on PMMA surfaces using an Atomic Force Microscope(AFM) tip under femto-second laser irradiation was investigated. Various lines and letters of different widths were processed, then fabricated patterns were tested by the same AFM tip in situ. Without optimization of the laser parameters, 100 nm resolution which is better than far field fabrication of our research group (~200 nm) was obtained.Keywords：nanofabrication;field enhancement;PMMA- 54
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Published：2020-08-13 -
Study on Attitude Solution for Strapdown Inertial Navigation System Based on Quaternion Algorithm
Abstract：To guarantee navigation precision of strapdown inertial navigation system (SINS), attitude solution for carrier is one of key technologies. We analysis strongpoint and defect of Euler algorithm, direction cosine algorithm and quaternion algorithm, firstly. Carrier attitude is compute separately according to quaternion algorithm and direct cosine algorithm, comparative deviation is obtained by contrasted these two solution deviation with theory result, therefore the validity of quaternion algorithm is proved. Increasing sampling frequency and adopting high-level compute algorithm is useful to monish compute deviation. Digital simulation and experiment results show that, the carrier attitude solution deviation is small by adopting this method, and it satisfies real-time needs for carrier self-navigation. The proposed attitude solution method offer an useful reference to strapdown inertial navigation technology applied in engineering.Keywords：SINS;Attitude solution;Quaternion algorithm;Navigation and control technology of aircraft- 97
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Published：2020-08-13 -
Model identification and Corrector design for the servo system of the Electromechanical Actuator
Abstract：A new frequency characteristic automated test method is proposed based on the digitization characteristics of the electromechanical actuator, then the system model of electromechanical actuator is identified, after further a series-wound corrector is designed to correct for the system. First the entire automated test process and data uploaded to the PC is controlled by the digital processing controller. Then these frequency characteristic tested data is identified to the high precision transfer function through using the Levy method. In the low and intermediate frequency, the maximal absolute error of magnitude between identified data and tested data is less than 0.8dB and the maximal absolute error of phase is less than 1.1°.On the basis of the transfer function, a lag-lead corrector is designed for the system, and the bandwidth of the corrected system is 138rad/s, which is better than 124rad/s by theory calculated. The corresponding experiments have been carried out, and the results show that the frequency characteristic test method has a high degree of automation, the identified transfer function has higher precision and the lag-lead corrector is suitable for the system. The whole process for the development of high-performance electromechanical actuator servo system provides a theoretical basis and engineering guidance.Keywords：Electromechanical Actuator;Frequency characteristic test;Levy identification;Lag-Lead Corrector- 38
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Published：2020-08-13 -
Research of Optimum Operation Mode Based on the Noise Characteristics of Electron Multiplying CCDs
Abstract：Based on the noise characteristics of electron multiplying CCDs, selecting suitable operation mode is favorable to make devices work at best state and obtain optimum image quality. This paper introduces the operation principle of inverted mode and non-inverted mode. The performance of dark current and clock induced charge is analyzed and compared under different operation modes. A mathematical model of optimum operation mode is constructed, taking operating temperature, integration time and total number of parallel transfers as parameters. Integration critical point is calculated and optimum operation mode is determined. According to the parameters of practical devices, the noise performance curve under optimum operation mode is simulated. The result offers the reliable theoretical basis for the operation mode selection of electron multiplying CCDs. It is of vital directive significance to the application and design of electron multiplying CCDs.Keywords：low light level imaging;optimum operation mode;noise analysis;electron multiplying CCD- 20
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Published：2020-08-13 -
A Two-step Algorithm for Estimating the Posture of Cameras Located in different points of View
Abstract：This paper proposed a new algorithm intituled a two-step method to estimate the posture of cameras located in multi-point of view. Firstly, the algorithm reconstructed the local 3D models of an object with the feature points in the first and second images. Secondly, the world coordinate frame was centered at local 3D models of the object, and every posture of the camera was estimated from the correspondences between the 3D feature points and the image feature points of the object. Experimental results on real images showed that the presented method is effective and the error of re-projection was less than 1 pixel.Keywords：Pose Estimation;two-step method;3D reconstruction- 37
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Published：2020-08-13 -
Infrared Image Background Suppression Based on 2rd Curvelet Transform and ProbShrink
Abstract：To detect weak targets in complex infrared background, this paper presents a new infrared image background suppression algorithm based on the 2rd generation Curvelet transform and ProbShrink. As the weak targets are described by high frequence of the 2rd generation Curvelet coefficients, we preserve these coefficients for later usage. Marginal statistics and joint satistics of the high frequence coefficents are used to find the positions of the target subband, then ProbShrink algorithm is used to suppress the background subband coeffients. Experiments show that our algorithm supress the infrared backgrounds well and preserve the weak targets.Keywords：2rd generation Curvelet transform;Probshrink;background subtraction;infrared image- 52
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Published：2020-08-13 -
An Improved method for Harris Corner Detection
Abstract：An Improved method for Harris corner detection is proposed while considering that there are two limitations exits in the Harris method. The first is its low localization to two kinds of corners(T and diagonal T). The second is its low efficiency. The improved method compare the value between the kernel pixel and pixels in the kernel pixel’s 8-neigbourghood while in which the value demonstrate the number of pixels that are similar to the kernel pixel. As a result of comparison, some of the pixels are reserved for the next step computation. If the value of the Harris corner response function(CRF) is bigger than the threshold value, the pixel will be considered as corner finally. The experiment show that the improved method achieves a better performance.Keywords：corner detection;Harris Method;Corner Response Function- 50
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Published：2020-08-13 -
The implement and improving of one area-based stereo matching algorithm
Abstract：Stereo matching is the most important and difficult part in the stereo vision. People have been working on how to establish matching cells between two homologous images more accurately and decrease the computational cost during matching. In the paper, firstly the images are rectified which makes the search range from two dimension to one dimension,and then adopt a latent constraint and one algorithm named SMP algorithm which is based on uniqueness constraint to achieve the matching of stereo pairs. This paper proposse one new method which make SMP algorithm more accurate than before.Using false constraint is to detect some fake match points gotten by SMP algorithm ,and get disparity map after interpolation.In addition, implementing Box filtering accelerating method is to decrease the computational cost and reduce program running time which is satisfied with application of real-time system.Keywords：stereo matching;area-based;uniquessness constraint;false epipolar constraint- 46
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Published：2020-08-13 -
On-Orbit Calibration of Star Sensor Based on Radial Alignment Constraint
Abstract：The internal parameters of star sensor such as focal length, principal point and focal plane distortion change after putting into use due to the impact of lunch, space circumstance, aging, etc. Therefore, the precision of attitude measurement decreases. As a kind of key technique to maintain high performance of star sensor during flight, autonomous on-orbit calibration is needed to correct the changed internal parameters. Independent of external attitude, an on-orbit calibration method of star sensor based on RAC (Radial Alignment Constraint) is proposed in this paper. Imaging model of star sensor is established according to radial alignment constraint firstly. Then, external and internal parameters are calculated from a single sky image using a two-stage method, and optimal solution of internal parameters is achieved from global optimization of multiple sky images. Simulation indicates that the proposed method can eliminate the coupling between external parameters and internal parameters effectively, and calculate these parameters precisely.Keywords：star sensor;On-orbit calibration;Radial alignment constraint- 34
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Published：2020-08-13 -
The Application of the Multiresolution Time Domain Based on Daubechies-Wavelet in the Electromagnetic Scattering
Abstract：Researching the multiresolution time domain (MRTD) and utilizing it to analyze the electromagnetic scattering of a target, in order to illustrate the advantages of the MRTD. First of all, the paper employs the Daubechies-wavelet, which is compact support, to be the basis, reduces the strict calculation formula systematically, while analyzes its character of dispersion and the absorbing boundary conditions-generalized perfectly matched layer (GPML). Then use this algorithm to analyze the electromagnetic scattering of a material ball. At last, the result can be simulated, which is the material ball’s radar cross section (RCS) of two-dimension and tree-dimension, furthermore, compares with other electromagnetic algorithms. With the same requirement of precision, MRTD not only has the good character of dispersion, but also use only half of the irregular cells to the FDTD, meanwhile, the calculation rate can be improve nearly 3 times and it makes the utilization of memory and CPU less. The GPML absorber also has a good effect. According to the result of analysis, MRTD demonstrates a lot of advantages in analyzing the electromagnetic scattering of a target.- 38
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Published：2020-08-13 -
The metheod which based on commuted band-pass filter
Abstract：As we all know, with the development of th eCharge Coupled Device, the application field of CCD is enlarging, the noise ofCCD become an obstacle which hinders the development of CCD. The noise isa major parameter of CCD which determine the signal to noise. We present a new method of CDS because of the shortcoming in thecurrent methods, that is, the metheod which based on commuted band-passfilter. We analyze the new method from white noise and 1/f noise and designhe mathematic model. The model is close to practice because of the dynamiccharacter.We discover a new method to reduce the noise of CCD which is betterthan the current methods in stability, cost and interfacing with the A/Dconverters. All of these is a useful experiment for reduction noise of CCD, itwill improve the signal to noise of CCD. Key words:CCD, signal no ise radio ,the metheod which based on commuted band-passfilter,noise, Double SamplingKeywords：The metheod which based on commuted band-pass filter- 47
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Published：2020-08-13 -
Enhancing Remote Sensing Image by the Contourlet Transform
Abstract：An algorithm for remote sensing image enhancement in space domain and transform domain based on the contourlet transform is proposed. Firstly, linear addition of original image and its details obtained by the Laplacian Pyramid transform is used for enhancing image in space domain. Then, the coefficients in different scales and different directions are obtained by the contourlet transform and a nonlinear function is introduced to modify the coefficients for enhancing image in transform domain. Finally, the image enhancement is implemented by reconstructing these coefficients. The experimental results show that this algorithm can get better effect for remote sensing image enhancement by comparing with other algorithms.Keywords：image enhancement;Contourlet transform;Laplacian Pyramid transform;Nonlinear function- 50
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Published：2020-08-13 -
Study on semiconductor cooling high frame rate CMOS digital camera and its imaging noise analysis
Abstract：For improving high-speed CMOS sensor imaging quality, reducing image sensor dark-current and spatio-temporal noise，the design of high frame rate CMOS digital camera system cooling by semiconductor refrigerator is introduced in the article. For this camera cooling system, It is implemented that refrigeration quantity can be controlled by the designed integrative multilevel semiconductor refrigerator. The difference in temperature of the sensor cooling temperature to surroundings temperature can attain max 40 degree. FPN( Fixed Pattern spatial Noise) of dark current can be reduced 50%, The random spatio-temporal noise can be reduced 90%, image SNR (Signal Noise Ratio) can be increased 6 dB. The designed cooling camera system has such advantaged features that high density of integration, compact structure, high resolution and high frame rate, high SNR, wide dynamic range, good imaging quality.Keywords：Semiconductor refrigeration;High frame rate;Digital camera;CMOS image sensor;Image noise- 37
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Published：2020-08-13 -
A Trous Wavelet Real-Time Image Fusion Algorithms Based on DM642 Fusion System
Abstract：A Trous wavelet real-time image fusion algorithms is presented based on DM642 fusion System. The fusion system is based on TI DM642 as its kernel processor，a latest high performance fixed-point DSP designed for video and image processing. It is built through the high operation speed of 600MHz, the high data transfer rates with EDMA and EMIF, the configurable video ports capable of glueless I/F to video decoder/encoder, and the dual-band image fusion system platform is constructed. A Trous wavelet transform is used to perform a decomposition of visible image in several scales in the system. The details extracted from which are fused into the infrared image. The fused images show the contribution of the visible image for discriminating lines and edges, while the infrared image provides an information on the detection of point targets. The simulated results show that dual-band image fusion algorithms cost 39.46ms, and fulfil 25 frame/s.Keywords：image fusion;A Trous wavelet;real-time processing;TI DM642- 38
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Published：2020-08-13
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