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Issue 1 ， 2004
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Use of diffractive-refractive optical system for correction of secondary spectrum
Abstract：The secondary spectrum of an aerospace wide spectrum(420.0～900.0 nm)and long focus(450 mm)telescope was corrected by combining diffractive and refractive optical elements, and the structural dimensions of diffractive lens and the aberrations of a telescope system were calculated as well. Computer simulation results showed that the secondary spectrum of the telescope objective lens corrected by combining diffractive and refractive optical elements was no greater than 0.08 mm, and the position aberration of a point on the axis was also very small, and repeated elimination of aberration was achieved. The optical transmission function was generally close to the diffractive limit, and the whole system designed could satisfy the actual operational requirements.Keywords：diffractive optical system;refractive optical system;secondary spectrum;telescopes;correction- 98
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Published：2020-08-12 -
Effect of digital zenith camera axis error on measurement precision of vertical deflection and its correction
Abstract：Due to machining accuracy and limited leveling precision of gimbals, there is always an inconsistency between the visual axis and the vertical rotational axis of the digital zenith camera and the plumb line, which leads to a big deviation between measurement precision and theoretical precision. In order to improve the measurement precision of vertical deflection, following the measurement principle of digital zenith camera, the effect of different axis errors on the measurement precision of vertical deflection is analyzed both quantitatively and qualitatively with necessary correction schemes suggested, and correction formula and post-correction error formula derived, and the image deflection resulting from axis inconsistency and its effect are analyzed as well. Various parameters of the system are determined in accordance with the actual technological level achievable, and simulations and simulation calculations show that the post-correction measurement error of the system is 0.4285".Keywords：zenith camera;axis error;precision analysis;vertical deflections- 50
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Published：2020-08-12 -
Wavelength calibration for PC2000-PC/104 spectrometer
Abstract：In order to reduce the effect of wavelength drift on measuring spectrum, a simple device was designed for wavelength calibration of PC2000-PC/104 spectrometer using Ocean Optics' HG-1 Mercury-Argon Lamp. Wavelength calibration coefficients were calculated through regression analysis after several ordinal numbers of CCD's pixels corresponding to Mercury-Argon Lamp's spectral lines were measured. The residuals of certain spectral lines were computed using the coefficients measured and the ones from factory, the degree of fitting for regression equation was estimated using the new coefficients. The final results validated the wavelength calibration model.Keywords：Spectrometer;wavelength calibration;regression analysis;coefficient of determination- 71
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Published：2020-08-12 -
Characterization of color scanners
Abstract：The nonlinear relationship between the scanner RGB signals and original image CIEXYZ or CIELAB values were obtained using the polynomial regression and the artificial neural network procedures. The reasonable structures of the polynomial and the artificial neural network were found for four color scanners. The better number of polynomial terms was 10, reaching the accuracy of 1.6～3.0 CDU(color difference unit)CIELAB average CD(color difference)and 8～13 CDU CIELAB maximal CD. And the reasonable number of hidden cells of the network was 6, reaching the accuracy of 1.4～2.6 CDU CIELAB average CD and 6～8 CDU CIELAB maximal CD. The test results showed that the polynomial regression and the artificial neural network techniques could be used to characterize commonly used color scanners, and the latter has a higher accuracy.Keywords：color scanner;characterization;color difference;polynomial regression;artificial neural network- 40
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Published：2020-08-12 -
Application of linear accelerometer for stabilization of nongyroscopic platform
Abstract：A necessary theoretical basis must be provided for the application of linear accelerometer in the platform stability control. The study of the application of linear accelerometer in electro-optically stabilized platform is briefed, and from the theoretical basis that the angular motion of a rigid body is irrelevant to the selection of reference point, a feasible arrangement scheme is proposed for the application of linear accelerometer for stabilization of platform so that the problems resulting from inconvenient installation of linear accelerometers in reality can be solved.Keywords：linear accelerometer;stabilization platform;angular velocity;angular acceleration- 51
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Published：2020-08-12 -
Slope error and aberration analysis for XRDX beamline toroidal focusing mirror
Abstract：A long cylindrical mirror bent into a toroidal shape in a special mechanism is usually used to focus the synchrotron radiations in both horizontal and vertical directions of X-ray beamline. The imaging principle and structural parameters of a XRDX beamline toroidal focusing mirror for NSRL use are discussed, the effect of aberrations and slope errors on the imaging quality is analyzed, the variation of curvature in meridional direction due to mirror bending, the error for theoretical value, and the thermal distortion resulting from the incident beam are discussed in detail. The actual measurements made with Marcam CCD camera showed that the theoretical calculations are in very good agreement with the actual measurements.Keywords：toroidal focusing mirror;slope error;aberrations;synchrotron radiation- 53
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Published：2020-08-12 -
Wavefront guided ablation on cornea
Abstract：The customized ablation based on the individual eye's wavefront aberrations and the ablation depth in corneal zone were studied and the hardware and software used for wavefront aberrations were developed for refractive surgery. According to this model, a scanning-spot laser with a 1.0 mm spot size and a 200 Hz repetition rate were used. Under the condition that the treatment area diameter is 6.5 mm, the PMMA result to myopia, hyperopia, astigmatism is that the maximal depth is equal and the time needed is a little bigger than the refractive errors of guided Lasik model, the result shows that the wavefront guided Lasik model is acceptable.Keywords：laser keratotomy;wavefront aberration;model;eye tracking system- 84
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Published：2020-08-12 -
Design of beam delivery system for RF CO2 laser ceramic substrate scriber
Abstract：The current requirements for laser ceramic substrate scriber systems are high light beam quality, fast scribing velocity, narrow scribing groove, small heat-affected zone, smooth cross-section, and independence of scribing quality from scribing direction. The light guide system designed can satisfy all the above-mentioned requirements, and it includes anamorphic lens, space filter, circular polarizer, Galileo defocusing telescope and focusing lens, and it has a scribing velocity of up to 10 m/min, a scribing width of less than 0.1 mm, and a scribing depth of more than 0.3 mm.Keywords：laser processing equipment;ceramic substrate;scriber;light paths;design- 64
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Published：2020-08-12 -
Development of constrictor with bio-feedback function
Abstract：In order to solve the problem of defecation-control for anus incontinence patients, an anus constrictor with biofeedback function has been developed by using a sensor to measure the pressure of patient' intestine following the principle of healthy people's defecation-control and constrictor's flab-reflex. A micro bi-directional-pump which exuberates of pumps water for a silica gel theca to simulate the constriction and flab function of a constrictor. The whole equipment is controlled by a MSP430F1121 micro controller. Animal experimental results show that, this equipment can control defecation very well.Keywords：medical instrument;constrictor;defecation-control;bio-feedback;bidirectional-pump- 50
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Published：2020-08-12 -
MEMS resonators and filters in RF systems
Abstract：The development of MEMS resonators and filters of RF systems including capacitive-comb transduced micro-mechanical resonator, free-free beam micro-mechanical resonator, FBAR resonator, cavity resonator, HF micro-mechanical bandpass filter, MF micro-mechanical filter, and transmission lines for tunable filter, both at home and abroad is reviewed, and the structures, performance and fabrications of these components are analyzed. The applications of these components are forecast from the performance requirements for current RF systems, and the development trend of MEMS resonators and filters is discussed as well.Keywords：MEMS;RF systems;resonator;Filter- 61
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Published：2020-08-12 -
Micro-drive positioning system based on PZT and its control
Abstract：An ID micro-drive table actuated by PZT, which has a parallel board framework, is described in detail, and the relationship between its thrust force and displacement is analyzed and validated with ANSYS simulation and experimental results. The system is controlled by a neuron adaptive PID controller, which features self-learning and adaptability, and easy calculation for simple structure, and the experiments made with the neuron adaptive PID controller indicate that the method proposed is effective, and the response time for a micro displacement of 20 μm is 12 ms.Keywords：micro-drive table;parallel board;PZT actuator;neuron;adaptive PID control- 61
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Published：2020-08-12 -
Comparative study of three regulating mechanisms for pipeline robot to suit different pipe diameters
Abstract：In order to enable a pipeline robot to suit pipelines with diameters in the range of 400～650 mm, three commonly used regulating mechanisms are proposed by analyzing the mechanical properties of each type of regulating mechanism and comparing the advantages and disadvantages of these regulating mechanisms. A ball screw pair regulating mechanism has been chosen to satisfy the actual engineering needs of this subject under investigation. The cylindrical pressure sensor on the ball screw can keep the pressure between the driving wheel and the pipe inner wall always stable so that the pipeline robot has adequate and stable traction force. Experimental results show that this regulating mechanism has a traction force output of 1404 N, and it can be used to suit pipelines with pipe diameters in the range of 400～650 mm very well.Keywords：in-pipe robot;ball screw pair;pipe inspection;regulating mechanism- 58
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Published：2020-08-12 -
Measurement of encoder errors with two-step method
Abstract：The encoder errors obtained by measuring the encoder errors with an encoder angular testing system consisting of polyhedrons and an autocollimator, include encoder errors and calibration errors of polyhedrons. According to the conditions for use of two-step method, the two-step method is applied to the processing of photoelectric rotary encoder errors, and the calibration errors of polyhedrons and the encoder errors are separately obtained. The results of error separation are close to the results obtained by other methods, but the volume of data to be measured for use of two-step method is dramatically reduced. The results of comparison show that, in comparison with other methods, this method can be used to improve the measurement efficiency by more than 90%, and shorten the measurement time by nearly 80%.Keywords：optoelectronic encoders;angle encoders;two-step method;error separation;discrete Fourier transform- 47
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Published：2020-08-12 -
Stereo matching in 3D measurement system using double CCD structured light
Abstract：The establishment of correspondence between two images is the precondition for 3D reconstruction in computer vision. By comparing several commonly used stereo matching methods, a highly effective stereo matching method, which is a combination of several matching methods, is proposed as a solution to the existing problem as detailed below: a series of gratings constructed by computer for phase demodulation is projected onto the object, and a series of black and white coded gratings constructed by computer is then projected onto the object, the distorted grating images are collected into the computer by CCD, the primary value of phase folded in zone is obtained through phase demodulation using the phase demodulation gratings, the period of phase is obtained through phase demodulation using structured light coding proposed, the true phase value is obtained by adding the two, the points with the same phase are fitted into a continuous cure by interpolation to realize the matching between two CCD images with the same curves, and the matching between the corresponding points in two images is obtained according to the epipolar constraint conditions. Experimental results proved the correctness and effectiveness of the method proposed.Keywords：3D measuring system;stereo matching;binary code light;phase demodulation;epipolar constraint- 63
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Published：2020-08-12 -
Application of object-oriented technology in vehicle dynamics simulation
Abstract：By analysing the crucial issues of vehicle dynamic simulation, a vehicle dynamic simulation system has been built using the object-oriented technology. The class of the system is analyzed with a class scheme worked out, and the way to establish a use case and an interaction diagram for used vehicle dynamic simulation are given. The corresponding simulation software is developed from the software model established. The straightline braking and turning braking safety and stability of a vehicle is an important part of vehicle dynamics, and simulation computation is made using the software developed for these two operating conditions, and the computation results are in good agreement with the actual operating conditions of the vehicle. Such special features as seal and package, and inheritance of the object-oriented technology have made the system structure well-defined, and the expansion and maintenance of system easy, thereby providing a basis for the development of vehicle steering system.Keywords：vehicle dynamics;object-oriented method;simulation- 59
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Published：2020-08-12 -
Detection of structured light strip center line based on genetic algorithm
Abstract：A way of detecting the structured light strip center line based on genetic algorithm, which is capable of optimizing the selection of image threshold value and accurately segmenting the light strip from the laser image, is proposed to improve the accuracy of the structured light 3D information acquisition system. The laser center line is further detected from the laser stripe through data processing and using alterable detection templates. Experimental results show that, with the adaptive rate of crossover and aberrance properly selected for genetic algorithm, the structured light strip center line can be accurately acquired to satisfy the system accuracy requirement.Keywords：image processing;structured light;genetic algorithm;direction template- 64
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Published：2020-08-12 -
Application of Monte Carlo simulation technology in OCT imaging contrast
Abstract：The relationship between OCT imaging contrast and objective numerical aperture(NA), focus depth, time gate has been studied with interrelationship established using the model established for the propagation of light in bio-tissue and the Monte Carlo simulation technology. Other simulation programs can not be used to simulate any effect of optical components, such as microscope and time gate, on OCT images. The drawback of other simulation programs to simulate the light propagation in bio-tissue only has been overcome by adding some lens permeation ratio functions and optical transmission functions to the models established. This can be used to analyze the relationship between the bio-tissue images and the bio-optical properties, and to promote the perfection and innovation of OCT configuration. Simulation results show that, while OCT is constructed, the larger the objective NAs of reference arm and sample arm are, the shallower the sample depth of bio-tissue is, and the more narrow the time gate of processing signal is, but it can not be less than laser pulse time, the better the imaging contrast of turbid tissue is.Keywords：optical coherence tomography(OCT);Monte Carlo simulation;bio-tissue;optical properties;imaging contrast;time gate- 60
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Published：2020-08-12 -
Electromagnetic compatibility design in optics and image processing equipment
Abstract：In order to improve the precision of 3D model obtained, suggestions were made for the elimination of electromagnetic interference signals on optics and image processing equipment. The alternator servo was first identified as the electromagnetic interference source through amplitude and frequency screening, the coupling path was then determined by calculating the interference voltage in the equipment grounding loop, and the CCD camera was finally identified as the sensitive interference receiver through comparison of components' sensitivity indexes. Electromagnetic compatibility designs were made one after another against the equipment electromagnetic compatibility specifications through analyses and calculations and by grounding, isolating, filtering and shielding.Keywords：image processing;Electromagnetic compatibility;3D mode acquisition- 69
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Published：2020-08-12 -
Correction of high-speed tri-CCD color disorder
Abstract：In order to improve the quality of image acquired, the causes of high-speed tri-CCD color disorder were analyzed, and several approaches including prismatic decomposition, exposure controlled by asynchronous trigger clock, and correction by software, are suggested for correction of high-speed tri-CCD color disorder. A prism splitter can be used to enable tri-CCD to receive red, green and blue beams separately so that color disorder can be avoided. An asynchronous clock can be used to control the exposures so that the sequence and delay of tri-CCD exposures can be adjusted to avoid color disorder. Real-time correction of color disorder can be achieved through software modification using data redundancy and data relocation technology. Substantiations made with a BASLER L301bc tri-CCD showed that the quality of images was significantly improved.Keywords：image processing;color tri-CCD;color disorder;prism splitter;asynchronous clock;data redundancy- 68
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Published：2020-08-12 -
NC surfacing of two off-axis aspheric mirrors
Abstract：A new way of solving and optimizing a best-fit sphere is proposed for surfacing and testing of two off-axis mirrors. A virtual fabrication program was developed for determination of CCOS CNC process parameters. The two off-axis aspheric mirrors surfaced are a convex mirror with an aperture of 165 mm×100 mm and a lightweighted concave mirror with an aperture of 770 mm×200 mm, and the design accuracies required for these two off-axis mirrors are better than 0.025 λ RMS with λ=632.8 nm over any 100 nm or 200 nm diameter sub-aperture. Inspections showed that the finish accuracies of convex and concave mirrors satisfied the design requirements, and they reached 0.023 λ RMS and 0.013 λ RMS respectively.Keywords：aspheric processing;off-axis asphere;computer controlled optical surfacing;virtual manufacturing- 56
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Published：2020-08-12 -
Calibration of soft X-ray detector
Abstract：In order to measure the relative spectrum distribution of soft X-ray source, it is proposed to calibrate the channel electron multiplier(CEM)using a silicon transfer standard photodiode calibrated by NIST. The quantum efficiency of the CEM has been determined using the calibration method proposed while CEM was biased to 1.3 kV. The analysis of calibration results indicates that the calibration error of CEM is 11%～17% in the 8～30 nm region.Keywords：soft X-ray detector;Soft X-ray;silicon photodiode;detector calibration;quantum efficiency- 50
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Published：2020-08-12 -
Role of Al layer in metallic-dielectric multiplayer
Abstract：A one dimensional metallic-dielectric multilayer coating was designed to suppress the long wavelength component in the emission spectrum of BaF2 crystal, while the short wavelength component is allowed to pass. The coating was composed of several periods of high(Al2O3)/low(MgF2)refractive index materials inserted in the metallic layer(Al). The multilayer coating was optimized and the effect of layer thickness error was estimated. The effect of thickness and distribution of the metallic layers was emphatically discussed. The multilayer coating was prepared through electron beam evaporation and the experiment results were in very good agreement with the calculated results.Keywords：multi-layer film;metal thin film;dielectric film;BaF2 crystal;Al- 43
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Published：2020-08-12
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