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Issue 10 ， 2009

Article

Electrically driving and controlling adaptive 128×128 element liquid crystal micro-lens array with tunable focal length

Vol. 17, Issue 10, Pages: 2351-2358(2009)

Abstract：A new liquid crystal (LC) micro-lens array is proposed based on structure and design methods of the single circular hole electrode LC lens with 128×128 elements. The LC micro-lens array is an electrically driving and controlling micro-lens array with tunable focal length. And the Indium Tin Oxides (ITO) glasses are used as the top and bottom substrates of the LC micro-lens array. The top electrode patterns are got by the methods of lithography and hydrochloric acid etching. The top electrode patterns have 128×128 elements. Every element is a single circular hole of 50μm diameter. The distance between circular holes is 100μm. The bottom electrode is just ITO film. And the thickness of LC layer between the top and bottom electrode is about 20μm. The focal length of the LC micro-lens array can be electric tunable from 50μm to 400μm under operating voltage from 0.2 VRMS to 5.0 VRMS. The result of the test shows that the point spread function of the LC micro-lens array is close to the theory values. And the relationship of operating voltage and focal length is inverse proportion. The imaging characteristic of the LC micro-lens array is like the imaging characteristic of conventional optical micro-lens array.
Keywords：adaptive optics;liquid crystal;large-area micro-lens array

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Published：2020-08-12
Improvement of detecting distance of UV warning system by Lowtran package and Gabor matching

Vol. 17, Issue 10, Pages: 2359-2364(2009)

Abstract：The false alarm rate of Ultraviolet (UV) warning is low, but it’s detecting distance is low too. On the other round the Infrared (IR) warning’s performance is opposite. Therefore we put forward a new kind of UV and IR composite alarm warning system. We analyzed the detecting mechanism, capture condition and effecting distance of the UV Warning System. Hereby, we put forward a mode which can estimate calculate the detecting distance of UV Warning System based on Lowtran. At the same time, we calculated the UV Warning System’s detecting distance to solid fuel missile. We analyzed the factor which can effect the detecting distance, and put forward a new way of matching the diagnostic image which can improve the detecting distance and based on Gabor. Of course we did some experiments to validate our theory and detecting mode. From these experiments we can clearly know that the detecting distance veracity can be controlled below 5%, and the warning distance can be improved from before 5km to now 8km. Using our detecting mode the complex warning system’s detecting efficiency and important ground equipments’ warning viability can be enormously improved. This mode can be used in other optics detection equipments.
Keywords：complex warning;Ultraviolet (UV) warning;contenting length;Target detection;Signal to Noise Ratio(SNR)

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Published：2020-08-12
Influence of mid- and high-frequency errors from optical manufacture on ratio of scattering loss

Vol. 17, Issue 10, Pages: 2365-2370(2009)

Abstract：In view of the primary mirror of large optical system, with the statistical optics theory and Harvey-Shack scatter theory, the mathematical model between the root-mean square (RMS) errors of mid- and high-frequency errors and the ratio of scattering loss (RSL) was established by assuming that the surface error is a stationary Gaussian random process, and the numerical computation and actual surface profile data of the model was validated. It is found that the RSL increases almost in exponential form with the increasing of RMS and the mathematical model agrees with the simulation results very well within the focused radius. The influence of the mid- and high-frequency errors on the RSL is less than 1% when the RMS of the mid- and high frequency errors are less than λ/63 respectively and the analysis provides the support for the further finishing and figuring of the optical surface profile.
Keywords：optical primary mirror;mid-frequency error;high-frequency error;ratio of scattering loss;root-mean square

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Published：2020-08-12
Study of the structure of the stay light suppressing of the white light coronagraph optical system

Vol. 17, Issue 10, Pages: 2371-2376(2009)

Abstract：“KuaFu Mission” is an “L1 + Polar” triple satellite project. KuaFu is composed of three spacecraft. A white light coronagraph (2.5 R⊙ to 15 R⊙ ) is a key instrument in the “KuaFu A”. It is the first time for us to fabricate the satellite-based coronagraph. The coronagraph requires the strict stray light suppressing. In this paper, based on the principle of the coronagraph, its optical character and the basic rules of suppressing the stay light are analyzed. The external occurred white light coronagraph is designed. In this system, the FOV is 4 degree, the resolution is 14 arc sec, the aperture is 30mm, the focal length is 200mm, the total length is 1080mm, the length of the optical structure is 370mm, and the MTF value at 37pl/mm is above 0.5. With the help of the conjugated stops, the four main stray light sources are totally suppressed, and a very high stray light suppressing level is obtained.

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Published：2020-08-12
Research on phase-shift laser range finder receiver system

Vol. 17, Issue 10, Pages: 2377-2384(2009)

Abstract：Phase shift laser range finding is widely used in many fields with its high measurement resolution. Measuring rate and resolution of the whole range finding system is determined by those of phase shift detecting and is influenced by the crosstalk for a given modulation frequency. Based on these, a new magnification of phase shift detecting is proposed which improves the measurement resolution 1/N times without increasing the measuring time. The under sampled technique is adopted to perform multi-frequency modulation in the same system which avoids using the mixer and other accessorial components. These reduce prior art scheme complexities and the influence of crosstalk. Week light with high frequency is incident on the avalanche diode (APD), the phase of the output signal from APD is delayed over that of the incident light which induces distance measurement error. A new method on suppressing the phase delay is presented by controlling the bias voltage acting on APD. For a modulation frequency of 18.5MHz, a wavelength of 650nm and incident light intensity of 0.5uW, the phase delay of 1.4o can be reduce to less than0.03o .The crosstalk mathematic model is set up. The crosstalk influences on phase shift measurement employing different electrostatic screen are given. The experiment results show that the phase shift measurement resolution is 0.014o and the distance measurement resolution is 0.3mm accordingly when the modulation is 18.5MHz.

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Published：2020-08-12
The effect of spherical shell or airborne eletro-optical platform to the optical axis pointing precision

Vol. 17, Issue 10, Pages: 2385-2391(2009)

Abstract：Abstract: The concentric glass spherical shell with the uniform thickness has been dominantly chosen as the transparent window, in front of the optical lens of airborne opto-electronic platforms. When the centers of spheres on the inside and outside surface have been misaligned during the producing, there exists the additional pointing error. In this paper, the theoretical expression concerning the optical path has been derived. The experimental result indicates that the measurement agrees well with the theoretical result. When the concentric misalignment of the spherical centers is 0.26 mm, the axial pointing error at 45 degree field of view reaches 0.075 degree, much bigger than the limitation which is set as 0.029 degree (0.5 mrad). In order to reduce the pointing error to 0.017 degree (0.3 mrad), the concentric misalignment has been expected under 0.10 mm.
Keywords：electro-optical platform;glass spherical shell;optical pointing precicion

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Published：2020-08-12
Effect factors of locating diffraction spot of two-dimensional phase plate by correlation function fitting extreme method

Vol. 17, Issue 10, Pages: 2392-2400(2009)

Abstract：In order to improve calculating efficiency of sub-pixel location of diffraction spot generated by two-dimension phase plate by correlation function fitting extreme method, three effect factors: template size, fitting window size and correlation function are analyzed in detail. Analyzing results show that the three effect factors all make bigger effect on calculation efficiency and the template and fitting window sizes make the biggest effect on locating precision during integer pixel searching. The optimal design of searching template and fitting window sizes are completed during sub-pixel location experiment of diffraction spot generated by two-dimension phase plate: the optimized template and fitting window sizes are 51×51pixel and 3×3pixel respectively. Comparing with the template of 131×131pixel which just includes the whole diffraction spot, the calculating time of whole locating process is shorted for 40%, so the calculation efficiency is improved without degrading location precision.

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Published：2020-08-12
Centerpart deformation influence on large aperture telescope’s altitude axis precision

Vol. 17, Issue 10, Pages: 2401-2405(2009)

Abstract：Altitude axis precision is important to performance of large aperture telescope. At practice, the tested result can not reach the system requirement, but the performance is well enough. The main reason is the deformation of centerpart. In this paper, 1m telescope’s centerpart is analyzed by the FEM, and then finding the Altitude axis max deformation versus pitch angle curve is sinusoidal curve, that is the same as the tested results curve. We also calculate the influence of deformation on axis precision .We use the compensation method: add the tested results to calculated result. By this way, the PV error of axis shake is reduced from 2.42″ to 0.95″, the RMS error is reduced from 0.7″to 0.3″, the system precision model is improved.This can provide theory of even larger telescope’s design and test.

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Published：2020-08-12
Stability of optical elements in large lasers

Vol. 17, Issue 10, Pages: 2411-2417(2009)

Abstract：Large high-power solid-state laser facilities have a very high requirement for the total positioning error budget, which is within 50 microns (祄) in general. The stability budget allocated to one optical element is only several microns or microradians (祌ad). For some optical elements, the budget is even smaller than 1祌ad. Thus the requirement for stability of structures is high. The stability design is illustrated for several key optical and mechanical systems in a large laser facility. Using the finite element theory, stability due to ambient vibration is analyzed for key optical elements and support structures to verify the validity of the optical and mechanical systems. The finite element (FE) models are built for the systems. The results show that the optical elements and the support structures can satisfy the designed stability indices and all the design margins are greater than 1.5 which is very conservative based on NIF?s research.
Keywords：high-power solid-state laser facility;optical elements;support structures;stability

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Published：2020-08-12
Analysis on the Performance Impact of the Noises in the Raman Amplifier
Yuan Jian-Guo,Ben Zhang,Wen-wei YE
Vol. 17, Issue 10, Pages: 2418-2424(2009)

Abstract：The Amplified Spontaneous Emission (ASE) noise, equivalent spontaneous emission factor and equivalent noise factor for the Raman Amplifier (RA) as well as the respective impacts of the Signal Noise Ratio (SNR) for optical receivers on the ASE noise, Rayleigh noise, optical fiber length and switching gain in the RA are theoretically analyzed, and then the Double Rayleigh Backscattering (DRB) noise are also theoretically analyzed and calculated, furthermore, the numerically related simulations are also implemented. The calculation and simulation results show that: the RA, compared with the Erbium-Doped Fiber Amplifier (EDFA), can improve the SNR of optical receivers under the condition of the same input signal; the equivalent spontaneous emission factor is less than 1 and will decrease with the increase of the switching gain, so this characteristics of the RA excels that of the EDFA; the condition that the Rayleigh noise of the RA can be ignored is that the gain of the RA is less than 15dB. In addition, some other significant conclusions to play an important role in guiding the optimal design of the RA are also obtained.
Keywords：Amplified Spontaneous Emission (ASE) noise;Rayleigh noise;double Rayleigh backscattering (DRB);Signal Noise Ratio (SNR);Raman amplifier (RA)

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Published：2020-08-12
Accuracy calibration of chip mounter alignment system based on grating

Vol. 17, Issue 10, Pages: 2425-2430(2009)

Abstract：Accuracy calibration is the key of high-precision chip mounter vision alignment system, affects the precision and quality of chip mounting. The traditional calibration usually requires a large number of matrix calculation to define the relation of camera coordinate, world coordinate and image coordinate . This paper presents a new calibration method based on grating , a group of data being similar to sinusoid is gotten by calculating the sum of gray-value of pixels in each column. These calculated data are elaborately showed a Lissajous figure by translation for pixel. The size mapping coefficient between the grating groove and their image pixels of the optical alignment system is calculated to realize the accuracy calibration . The result of experiments indicates that the error of the new calibration method is little ,it can meet the precision needs of an automatic chip mounter vision alignment system.
Keywords：chip mounter;alignment system;accuracy calibration;grating;Lissajous figure

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Published：2020-08-12
New Approach Study for Precision Evaluation of 3D Optical Measuring System based on Forgings & Stampings and its Dies

Vol. 17, Issue 10, Pages: 2431-2439(2009)

Abstract：VDI2614/2634 is a kind of commonly method of precision evaluation for 3D optical measuring system .The national standard named measurement specification of optical 3D geometry for forgings & stampings and its dies is being formulated. A new method of evaluation for optical measuring system imposed on forgings/stamping has been proposed, the testing project has been drafted, then each group is considered as a single subsystem, that the minmax-difference， mean difference and mean square value of each group have been calculated. The system-relatively error of subsystem is defined because that mean difference is divided by measurement mean value, the accidence-relatively error of the subsystem is defined because that minmax difference is divided by measurement mean value. Relatively error and weight are considered completely, that the system error and accident error of the measurement system may be calculated. For the reunification of evaluation standard, the concept and calculation method which comprised of standardized system precision, standard accidental precision and standardized precision are put forward. The XJTUOM optical measuring system developed by ourselves has been evaluated by means of this approach, then the conclusion that the standard precision 0.89 is reached out. Formulating reference of national standard is provided with this approach.
Keywords：mean value;minmax-difference;standardized precision;optical

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Published：2020-08-12
Thermal Design and Proof Test of CCD Component in Spectral Imaging Apparatus

Vol. 17, Issue 10, Pages: 2440-2444(2009)

Abstract：As a complex space optical remote sensor with multiple optical channel and detectors, the optical-mechanical structure and the mounting mode and the load distribution in the spectral imaging apparatus present a asymmetric form. It’s very complex and difficult to practice heat control in the spectral imaging apparatus. CCD component is important element of image-forming system, furthermore, it’s a difficult point at the same time. The degree of thermal design have a direct reference of imaging quality. The characteristics of CCD component heat control in the spectral imaging apparatus are discussed and analysed. The corresponding thermal design scheme of CCD component is introduced and this component is simulated by means of software IDEAS-TMG. The guide line of thermal control is achieved. At last, the thermal design scheme is verified by proof heat test.
Keywords：spectral imaging apparatus;CCD component;thermal analysis;thermal test

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Published：2020-08-12
Fiber optic electromagnetic sensor based on magnetic fluid

Vol. 17, Issue 10, Pages: 2445-2449(2009)

Abstract：Abstract: A novel fiber optic F-P electromagnetic sensor is developed based on magnetic fluid as the medium in F-P interference cavity. A signal demodulation method based on fiber Bragg grating wavelength scanning is proposed. Theory and principle of electromagnetic-controlled refractive index of the magnetic fluid is described as well as the structure of the sensor system. Preliminary experiments are carried out, and the results indicate that there is a fairly good linearity of the measurement characteristic, and the thickness of magnetic fluid film and environmental temperature will affect the measurement results.
Keywords：fiber optic F-P filter;magnetic fluid;fiber optic sensor;electromagnetic measurement

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Published：2020-08-12
Research of the primary support technology of space high resolution imaging spectrometer

Vol. 17, Issue 10, Pages: 2450-2455(2009)

Abstract：In order to improve the stability of the opt-mechanical system which was produced by the primary support of the space High Resolution Imaging Spectrometer (HRIS), the expressions of the stability of the opt-mechanic system were analyzed from three ways. The lugs, which were the traditional support structures to the space optics remote sensing, were used to support the opt-mechanical system, but the results showed that it couldn’t meet the need of the three-mirror-off-axis anastigmat (TMA) imaging system. Then, a new coupling support structure by two axes was advanced and some theory analysis was done to it. Finite element analysis of the 3D model was realized by software MSC.PATRAN during the optimum designing. The results showed that the one mode of natural frequency was 95Hz under sine vibration loading. The maximum RMS value of the mirror surface was 12nm and the maximum PV value was 60nm. The angle rotation by Z axes of the primary mirror was reduced from 55''to12''. The spectrum data of the opt-system under the hot vacuum environments verified the analysis results. Coupling support structure was feasible to meet the need of the rigidity and the heat-stability of the opt-mechanical system.
Keywords：high resolution imaging spectrometer;support technology;structure design

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Published：2020-08-12
Electromagnetic Locking Device Based on Self-locking For Magnetic Bearing Wheel
Han Bang－Cheng,Qiang Liu
Vol. 17, Issue 10, Pages: 2456-2464(2009)

Abstract：Abstract：Due to the launch vibration environment, the use of locking device is necessary for magnetic bearing wheels. We developed a electromagnetic locking device based on self-locking for our magnetic bearing reaction wheel, the mass of the locking device is 158 gram, and the dimension is 45mm×49mm×40mm. The link created by the locking device can be completely released by the compression spring. The mathematical models of lock and release are established. The curves of the locking force versus displacement and the releasing force versus displacement are given. The force of holding locking is 133.8 N, and the force of holding releasing is -9.4N. The ground environment and space environment are considered in this paper, the effect of gravitation is very small for the locking device. The locking device is tested by the vibration table.
Keywords：magnetic bearing wheel;locking device;self-locking

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Published：2020-08-12
Study on microfabrication technology of multichannel flexible neural microelectrodes

Vol. 17, Issue 10, Pages: 2465-2472(2009)

Abstract：Objective: Multichannel flexible neural microelectrodes were designed and fabricated. The fabrication process of microelectrodes was studied. Method: A microfabrication technology was introduced to manufacture flexible microelectrodes based on a new flexible substrate material, parylene C, due to its excellent electrical insulating, mechanical and biocompatible performances. Result: A 36 channel flexible neural microelectrode was fabricated, arranging in a 6×6 square grid pattern. The size of microelectrode was 150m (circular) and 150m×150m (squre), respectively. The line width of metal traces was 30m. It was found that the surface of microelectrode was smooth and the outline of microelectrode was distinct. The impedance of microelectrode was only 7k or so, and reduced as frequency increasing, showing a high-pass behavior. Conclusion: The microelectrodes and flexible substrate were integrated by the microfabrication technology. Fabricated microelectrodes had nice quality and good electrical property, which was suitable for the application in retinal prostheses.

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Published：2020-08-12
Experiment on bending of Al2O3 ceramic slice with CO2 CW-laser

Vol. 17, Issue 10, Pages: 2473-2479(2009)

Abstract：As an important application of Laser Rapid Forming, laser bending technology of brittle materials has broad prospects. In this paper, experiments on bending of Al2O3 ceramic slice with CO2 CW-laser are carried out at various laser processing parameters, including laser power and scanning velocity. Laser linear energy density is introduced to discuss the best processing parameters, and bending characteristics are briefly analyzed according to the high temperature properties of Al2O3 ceramic. Experimental results show that the Al2O3 ceramic slice is bent by CO2 CW-laser, and the bending angle reaches up to 2° . Laser bending processing of Al2O3 ceramic slice is strongly sensitive to temperature. There exists a critical temperature, above which, the bending angle increases greatly. The best rang of laser linear energy density for bending Al2O3 ceramic is 17～24 J/mm.
Keywords：laser bending;Al2O3 ceramic;temperature sensitivity;plastic deformation

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Published：2020-08-12
Calibration Techniques Research on Position Topography Measurement

Vol. 17, Issue 10, Pages: 2480-2485(2009)

Abstract：To effectively realize camera calibration on position topography measurement, based on the camera intrinsic parameters model, a multi-camera parallel calibration method is proposed. According to active vision theory, four cameras are installed at four linear independence positions on the measuring support, and a parallel device is applied to drive these cameras shooting at he same time, so as to accomplish the shooting effect of three linear independence translation. The calibration experiments of position topography measurement are designed based on this calibration method, the experiments show that relative error of fu /fv is less than 3.87%, the absolute error of u0、v0 is less than 4 pixels, the variation range of s is 3 times. This method is fit for convenient and quick calibration on position topography measurement.
Keywords：Position Topography;Topography Measurement;Camera Calibratio

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Published：2020-08-12
Measurement of Short Arc Based on Centre Constraint Least-square Circle Fitting Method

Vol. 17, Issue 10, Pages: 2486-2492(2009)

Abstract：Least-square method is usually adopted for fitting of geometric elements in coordinate measurement. However, in the process of short arc measurement, it is difficult to keep precision due to lack of feature points and influence of noise jamming. Aimed at measurement of short arc based on machine vision system, centre constraint least-square method is proposed in the study. Influence of central angle on measurement error of circle centre and radius adopting least-square method is analyzed. It was proved that the measurement error is less than 0.01mm by using our method to measure the radius of a short arc with 20-degree central angle. Results of comparative experiment show that centre constraint least-square method can improve the accuracy of circle fitting efficiently in short arc measurement.

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Published：2020-08-12
Experimental Study on the Dual-Lapping Process with Sapphire Crystal

Vol. 17, Issue 10, Pages: 2493-2498(2009)

Abstract：In order to achieve high efficiency and low damaged layer during sapphire crystal lapping process, experimental research on rougness, lapping uniformity and sub-surface damaged layer were studied in this paper. Sapphire with (0001) orientation was lapped by 280 mesh boron carbide abrasive grits, firstly, effects of lapping times on the material remove rate and surface roughness were investigated, then micro-surface uniformity was also presented by using WYKO equipment. Finally,Nano-indentation test was applied to measure the depth of damaged layer according to the hardness or modulus variance. Experimental results show that sapphire crystal with average roughness Ra0.523μm and Rt<6.0μm, depth of sub-surface damaged layer not more than 1μm, could be achieved by dual-lapping abrasive machining with 280 mesh boron carbide grits in 120 minutes.
Keywords：sapphire;dual-lapping;uniformity;sub-surface damage

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Published：2020-08-12
Parameter identification based on a modified annealing algorithm for articulated arm CMMs

Vol. 17, Issue 10, Pages: 2499-2505(2009)

Abstract：Errors of structural parameters are one of the main factors causing uncertainty of articulated arm coordinate measuring machines (AACMM); therefore the accuracy of AACMMs can be improved efficiently by structural parameters identification. The homogeneous transformation equations of 6-DOF AACMMs were established based on Denavit-Hartenberg model. A method to identify structural parameters with a cone-shape hole was analyzed. A modified simulated annealing algorithm (MSAA) was presented to identify the structural parameters of the AACMMs. The MSAA can keep the best solution during search, and reduce the search range when the solution approaches the global minimum, which can improve the search efficiency and accuracy. The definition of single-point repeatability was deduced, and the method using single-point repeatability as the objective function to identify structural parameters of AACMMs base on the MSAA was presented. A 6-DOF AACMM was used to carry out experimental tests to evaluate the efficiency of the method presented, the results show that after identification the repeatability and length measurement accuracy of the AACMM are improved 7.87 and 5.59 times respectively.
Keywords：Articulated Arm Coordinate Measuring Machine (AACMM);structural parameter identification;calibration;Accuracy;Simulated Annealing Algorithm (SAA)

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Published：2020-08-12
Vertex manufacture precision analysis of the axicon

Vol. 17, Issue 10, Pages: 2506-2511(2009)

Abstract：Based on the Fresnel diffraction theory, the influence of the axicon with vertex manufacture precision is analyzed in detail. It is equal to a plano-convex lens focusing the beams when the vertex is machined to a circle. The blunt-tip region of a real axicon can be described actually by a hyperbola, and the aberration non-diffracting beams will be formed for the interference oscillation. We present the theoretical derivation, simulation analysis of the beam propagation and transformation with different vertex manufacture of the axicon. Finally, a method of modifying the influence of a hyperbola-tip axicon is proposed and the correction effect is ideal that is guiding significance to the application of the real manufacture axicon.
Keywords：axicon;vertex manufacture precision;non-diffracting beam

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Published：2020-08-12
Surfaces roughness study in diamond fly-cutting of micro-structured surface

Vol. 17, Issue 10, Pages: 2512-2519(2009)

Abstract：In order to obtain micro-structured surface with nano-surface finish, a three-dimensional diamond fly-cutting system is established based on ‘Nanosys-300’ ultra-precision machining system. The effects of spindle speed, feed rate, as well as the depth of cut on the roughness were investigated respectively. The analytical result of theoretic surface roughness (TSR) shown that TSR was constant along the normal direction, while TSR was periodic variety along the feed direction. TSR was reduced with the decreasing of feed rate and nose angle ε of tool or increasing of cutting radius. The experimental results revealed that roughness Ra was reduced with the decreasing feed rate and depth of cut on PC. While it was increased with the decreasing depth of cut or increasing feed rate on LY12. The spindle speed didn’t have a signify impact on Ra for both materials. The roughness of 38nm on LY12 and 43nm on PC were achieved. Micro pyramid array and v-groove array were obtained with a pointed V-shaped single crystal diamond tool on aluminum alloy LY12.
Keywords：ultra-precision machining;Micro-structured surface;Fly-cutting;diamond tool;surface roughness

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Published：2020-08-12
A New Prefilter Method for Initial Alignment of Ring Laser Gyroscope SINS on a Rocking Base
Lv shaolin,Ling XIE,Jiabin chen
Vol. 17, Issue 10, Pages: 2520-2527(2009)

Abstract：When the initial alignment of ring laser gyroscope SINS is performed on a rocking base, the noise of ring laser gyroscopes and accelerometers will increase. Then, it will need more time to accomplish the initial alignment. Sometimes, the large noise will make the alignment fail. Only with a lowpass filter, the output of sensors will still suffer from large noise. Wavelet can suppress the noise brought by the dither motion of base. However, it has a high computational complexity and block-processing structure, which makes it hard to be implemented online. To solve this problem, a new prefilter method is proposed in this paper. After the output of sensors is filtered by the lowpass filter, a steady-state Kalman filter which uses a hidden Markov model will be used to filter it. Then, the large sensor noise brought by the dither motion of base can be lowed down to a very low level. Experiment results show that this prefilter method can work efficiently with a low computational complexity and help SINS accomplish the initial alignment on a rocking base.
Keywords：ring laser gyroscope;strapdown inertial navigation system;initial alignment;hidden Markov Model;Kalman filter

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Published：2020-08-12
A parallel 3D skeletonization algorithm based on sort ascending rechecking

Vol. 17, Issue 10, Pages: 2528-2534(2009)

Abstract：A new parallel 3D skeletonization algorithm based on sort ascending rechecking is proposed. A new method, named 8-6 trees, to identifying simple points is designed. Simple points can be identified by traversing 8-6 trees, without calculating Euler characteristic. Distance transform and parallel 6-subiteration thinning are combined by a new label rule and sort ascending rechecking ,remedies the defects of usual sequential algorithms. The influence of noise is controlled by preserving convex vertexes. Skeleton generated by our algorithm is in accurate position, with correct connectivity and topology. This algorithm is applied to a large number of 3D images and good results were achieved. Furthermore, this algorithm can also be used to skeletonize 2D images.
Keywords：skeletonization;8-6 trees;sort ascending rechecking;parallel algorithm

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Published：2020-08-12
Double-channel Fast Blind Detection of Satellite Communication Signals
Geng Peng
Vol. 17, Issue 10, Pages: 2535-2541(2009)

Abstract：Power spectrum detection has robust performance in higher SNR, but in lower SNR the performance will deteriorate sharply. However, bispectrum detection may obtain higher detection probability by only utilizing bispectrum information of non-Gaussian noise and signals in lower SNR. Aiming at complex time-varying satellite communication reconnaissance environment with lower SNR, a double-channel blind detection algorithm based on energy spectrum and bispectrum slice of satellite communication signals is presented. The method is favorable for heightening detection performance with increased available information by making use of second and third order statistic. Computational complexity analysis indicates its speediness and simulation results affirm its validity.
Keywords：information processing technology;blind detection;power spectrum;bispectrum slice;satellite communication signals

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Published：2020-08-12
Study on colorimage tracking algorithms based on particle filter

Vol. 17, Issue 10, Pages: 2542-2547(2009)

Abstract：Abstract：In Video tracking, detection and tracking need two algorithms. The process is complex and need much time which detection and tracking is. In this paper a hybrid valued sequential state vector is formulated. The state vector is characterized by information of target appearance and of location. Particle filter-based method implements detection and tracking. In order to reduce process time and think of pixel position in tracking field, feature histogram of color-based is as observe vector and used posterior estimate. The experimental results confirm that method can detect and track object in 14.37ms successfully. The method is robust for rolling and scale.
Keywords：target detection;Tracking;particle filter;feature histogram

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Published：2020-08-12
Research on high speed and high capacity image recorder based on NandFlash

Vol. 17, Issue 10, Pages: 2548-2554(2009)

Abstract：Considering that single NandFlash has low speed, small capacity and existing invalid block, the reliability storage solutions of high speed and high capacity image recorder based on NandFlash is proposed. The structure and characteristics of NandFlash is analyzed .Then by separating written invalid block from non written invalid block, the classified data matching and detection mechanism based on CAM is proposed to raise invalid block information matching speed. The SRAM array backup is adopted to prevent data writing error. Based on this, when invalid block is occurring in multiple pipelining grade during writing，dual pipelining mechanism which is based on dual bus structure is proposed to prevent interruption of writing pipelining. The experiment which is based on hardware platform indicates the algorithm can identify the invalid blocks in 5 system clock period. The consistent storage speed is up to 960 Mb/s, consistent read speed up to 1.152Gb/s and erase speed up to 27.3Gb/s.The system storage capacity is up to 80Gbytes.
Keywords：invalid block management;content addressable memory (CAM);redundant backup;dual pipelining;dual bus structure

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Published：2020-08-12
Study on Palm-print Images Sampling Equimpment

Vol. 17, Issue 10, Pages: 2555-2560(2009)

Abstract：This paper proposes a new palmprint sampling system based on the DSP corresponding to the current system structure that it adopts scanner or image sampling card to sample palmprints and realizes the recognition process with PC. This paper a new palm-print sampling system based on DSP. The system changes the palmprint images into digital images through the SAA7113H vision decoder and realizes the sampling and recognition in the off-PC state by taking advantage of the TI DSP TMS320VC5509A control chip. The best optical source and optical structure to sample the best plamprint images is acquired by the experiments whose result show that this system satisfies the real-time requests and has a very high recognition rate.
Keywords：DSP;ring illuminator;SAA7113H;palmprint sampling

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Published：2020-08-12
The Color Romance for the 3D-Reconstructed Surface of Structured Light based on the Colorized Image

Vol. 17, Issue 10, Pages: 2561-2568(2009)

Abstract：The color romance technology has attracted extensive attention, because many industries have not been satisfied with the 3D figuration information and they also need the color information of the subjects. But in the process of assigning the color directly, there are some errors caused by the difference of the geometrical properties of the measured surface. In order to reflect the change of the geometrical properties of the measured surface, the measured surface is divided into several sub-units, so the change of the geometrical properties of the measured surface can be considered as the change in relative position between the sub-units and the projector as well as the camera. Further, the mathematical model is established based on the position relation mentioned above. The relation between the slope change of the sub-units and their incident intensity and scattered intensity is analyzed. Combining with the impact of the relation on the color information, the selection principle of the sub-units is given to eliminate the errors of the color romance brought by the impact of the incident intensity and the scattered intensity. Further, a kind of color romance method which is not affected by the incident intensity and the scattered intensity is given. The emulation and the practice experiment of the color romance are executed making use of the 3D measured data given by the 3D measurement system. The results show that the incident intensity and the scattered intensity of different parts of the measured surface is uniformly corrected, and the color information of the romanced measured surface is almost uniform with its real color, and even changing the measuring angle, there is a good visual effect as well.
Keywords：color romance;sub-units;color image;light intensity correction

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Published：2020-08-12
Signal design method for seismic vibrator based on ternary pseudorandom coding

Vol. 17, Issue 10, Pages: 2569-2575(2009)

Abstract：Seismic response to conventional Chirp sweeping vibrator signal has the shortcomings of high side lobs and low resolution. This paper aims at vibrator seismic exploration , investigating pseudo-random encoding sweeps, then contrasting binary encoding sweep working mode and ternary encoding, building binary encoding and ternary encoding , and gaining pseudo-random list by pseudo-random code. The developed ternary pseudo-random encoding sweeps signal generator is embedded into the electromagnetic driving Vibrators with the independent intellectual property rights in the laboratory, at last we analysis auto-correlation function and gained pseudo-random coding sweep signal which can be used in seismic exploration.
Keywords：Vibrator;Ternary Pseudo-random Sequence;code;correlation noise

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Published：2020-08-12
An adaptive algorithm based on morphological top-hat transformation to segment Chinese square seal in bank check

Vol. 17, Issue 10, Pages: 2576-2585(2009)

Abstract：Abstract: Objective: It is an open problem in image analysis based seal verification that how to segment a binary seal image out of a check image without distortions. An adaptive morphological segmentation algorithm based on top-hat transformation is proposed to accurately extract a binary Chinese square seal from a bank check. Method: A grayscale square seal is extracted from a color bank check according to the color information. Different Chinese characters have different stroke features and background evenness. To process each character in the square seal respectively, the seal is divided into four sub-squares. The background across each sub-square of the grayscale seal image is smoothed by top-hat transformation. The size of structuring element in top-hat transformation might have a great influence on the segmentation. An adaptive method is proposed to iteratively estimate the proper size of the structuring element according to the local foreground area. In each sub-square, the optimal sizes of the structuring elements respectively for the imprint frame and the character are estimated respectively. With their optimal structuring elements, the character and the imprint frame in each sub-square are filtered by top-hat transform and binarized by Otsu’s method. Result: The experiment result shows that when segmenting 350 different square seals in bank checks, 2 segmented seals have distortions. Conclusion: The proposed algorithm can correctly segment Chinese characters with intricate and dense strokes in a bank check square seal. Adhesion and incompleteness distortions in the segmentation results are reduced, even when the original square seal has a poor quality.
Keywords：Chinese square seal;segmentation;adaptive segmentation;top-hat transform;structuring element

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Published：2020-08-12
A pattern matching and parameter self-adaptive based PCB solder joint inspection algorithm
Wu Fu-pei,Yong-cong Kuang,Xian-Min ZHANG,Gaofei Ou-yang
Vol. 17, Issue 10, Pages: 2586-2593(2009)

Abstract：In order to improve the inspection success rate and velocity of the in-line Automated Optical Inspection (AOI) system of Printed Circuit Boards (PCBs), the solder joints of a PCB are studied. The solder joint images are acquired by a structure illuminator and a 3-CCD color camera. Based on the images, the area features of the conventional kinds of the PCB solder joints such as good, excessive, poor, pseudo are extracted with respect to the key sub-region in a solder joint. Five kinds of feature matrixes models of solder joints are presented. A pattern matching algorithm for inspecting the solder joint is developed by maximum the similarity of the same kind of solder joins. To solve the problem of the thresholds determined by experience, a parameter self-adaptive learning strategy is presented. Finally, a 1040 chip solder joints PCB is inspected. Experimental results show that the success rate is up to 96.5% and the inspection time is 9 seconds using the proposed algorithm, which indicates that the proposed algorithm can achieve both high success rate and inspecting velocity.
Keywords：automatic optical inspection (AOI) system;Solder Joint Inspection;feature matrix;pattern matching;parameter self-adaptive

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Published：2020-08-12
The Design and Implementation of Data Traffic Satellite Communication Simulation System

Vol. 17, Issue 10, Pages: 2594-2599(2009)

Abstract：A design method of data traffic satellite system has been developed. Firstly through band-pass sample theorem, the simulation system sample rate has been designed and furthermore the lowest equivalent carrier wave formula was deduced, the deduced formula is able to be applied into other simulation system. At the same time, the equivalent design methods to the practical system time and frequency spectrum were presented. Secondly according to the system function structure, the system software frame and running threads was studied. Finally corresponding function models has been realized. Two work modes including independent running and network controlling were provided, functional models, which were required by the transmitter and receiver of data-traffic satellite system and including radio modulation, were simulated integrally. Based on the evaluation model, the frequency spectrum, eye pattern and relation of BER and SNR are presented, and the simulation results are in agreement with theoretical values.
Keywords：satellite communication;Sampling;simulation equivalence;concatenated coding;modulation demodulation

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Published：2020-08-12
A Quick Adaptive Identification Algorithm Based on Three Order Nonlinear Volterra Model

Vol. 17, Issue 10, Pages: 2600-2605(2009)

Abstract：abstract: Objective: In the project of RFID flip chip package’s development, the high speed manipulator have obvious nonlinear and time-variable characters. For this reason, the linear control can’t satisfy requirement , so applies nonlinear adaptive inverse control. The key of this method is to identify the high speed manipulator with three order Volterra nonlinear model in limited time and with sufficient accuracy. But it’s hardly to satisfy real-time requirement with conventional method. This paper proposes a quick identification algorithm to resolve the problem. Method: Firstly, constructs high order input vector by low order input vector according their structure character. Next, speeds up estimates high order kernels based on low order kernels according their correlation. finally, uses linear variable step-size LMS strategy in nonlinear algorithm, and proves it’s convergent using Lyapunov global stability theorem. Result: By the experiments of identified a manipulator using conventional method and proposed method respectively, the result shows this algorithm reduces identification time form 100 ms to 30 ms, improves convergent speed 3.3 times, and reduces maladjustment 93.3%, as well as have higher precision. Conclusion: It can satisfy the requirements of real-time and identification precision .
Keywords：Non-linear;adaptive;identification;Volterra;Quick algorithm

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Published：2020-08-12
Mean Shift tracking algorithm with adaptive tracking window

Vol. 17, Issue 10, Pages: 2606-2611(2009)

Abstract：Objective: An new algorithm to estimation the scale and orientation of the tracking window is presented in order to solve the problem that traditional Mean Shift based tracking algorithm often fail when tracking a deformable target because of the unchanged tracking window. Method: Firstly, the principal components of the variance matrix are adopted to compute the scale and orientation of tracking target. Further, the similarity measure and Kalman filter are used to update the tracking window. Result: The experimental results show that the algorithm can be implemented in real-time and can adapt to the changes of scale and orientation of the moving object. Conclusion: It can satisfy the requirements of tracking non-rigid objects.
Keywords：Mean Shift;target tracking;principle component analysis;deformable object;Kalman filter

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Published：2020-08-12
Design of real-time infrared image enhancing system

Vol. 17, Issue 10, Pages: 2612-2619(2009)

Abstract：There is a severe contradiction between the 14bits output data of the infrared thermal imager and the 8bits input data of the monitor in a real-time infrared image processing system. A novel algorithm for real-time infrared image enhancement based on FPGA is proposed not only to solve this problem but also satisfy the real-time and mass data need of the system. First, an image mean filter is used to compute the local limit values for each frame dynamically. Next, a multi-level average statistics method is designed to calculate the values of segment points for each gray normalization partition. Finally, the means of different linear normalization on different gray level segments is taken to enhance the infrared image. The whole algorithm is developed on the FPGA hardware with Verilog language. Experimental result shows that this algorithm settles the problem that the output values of un-cooled focal plane array detector are varied with its working duration. Moreover, the algorithm could reduce the impact from little bad pixels with very large values, and enhance the details of an image which has some objects of high and low temperature simultaneously in a scene. Compared with histogram projection, one of the most traditional image enhancement methods, this algorithm shortens the computation time about 1.38ms and consumes only 1/42 memory resource than histogram does. Therefore, it could be implemented by FPGA easier and perform better in a real-time infrared image enhancement system. In terms of engineering application, the proposed scheme with simple architecture, high reliability and low cost characters could provide a valuable reference for other design of a real-time infrared image processing system.
Keywords：local limit value;multi-level average;linear normalization;image enhancement;real-time processing

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Published：2020-08-12
Super-resolution imaging method with detectors of special-shaped pixels
Liu Yan-Yan,Xin Zhang
Vol. 17, Issue 10, Pages: 2620-2627(2009)

Abstract：As optical imaging era transits to electro-optical (E-O) imaging one generally, spatial resolution is mainly limited by detectors for the overwhelming majority of imaging systems. It is obvious that the prior is to enhance detector resolution for high-resolved or even super-resolved imaging system. The spatial resolution of detector mainly depends on the effects of both the sampling process and the size and shape of active area. So far, there have been two main categories of solutions: one is the straightforward method of fabricating very small pixel, but it has a limit and causes some performances of detector going down; the other is called as super-resolution reconstruction, which is to solve undersampling phenomenon caused by insufficient sampling frequency. It is to decrease aliasing and increase spatial resolution based on the oversampling theory, but it has large limitation for it has another limitation that is the aperture effect of pixel. According to the pros and cons above, a new method is proposed based on special-shaped detectors for increasing simultaneously both the sampling frequency and the detector cutoff which depends on the aperture effect of pixel in spectral domain. It is realized with two detector-arrays of special-shaped pixel where each pixel is deducted a quarter. It is proved that if a small plot of active area per pixel is deducted and the frequency-response distribution of the complement will equal to that of the deducted part without consideration of the amplitude. And then multiple mis-registered frames available are used to solve the grayscale matrix and reconstruct the super-resolution image in the post-detector processing. It can not only enhance the detector resolution, but also weigh rationally the other performances. Finally it is analyzed and proved through theoretical assessment and specific experiment that the imaging method with detectors of special-shaped pixels should improve spatial resolution better for the detector-limited systems.
Keywords：super-resolution imaging;special-shaped pixel;pixel subdivision

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Published：2020-08-12

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