Acta Photonica Sinica
Co-Editors-in-Chief
Yue Hao
GAO Zhiqiang, and LI Yong

It is an interesting thing to output high quality digital hologram (Computer Generated Hologram) under limited grey level. The reconstructed image quality of digital hologram was studied with adjusting the grey level of hologram, according to its histogram. The grey levels whose ratios were relatively small were cut down, and the grey levels whose ratios were relatively large were expanded. Firstly, the change of diffraction efficiency of digital hologram after grey level adjusting was studied in theory. The diffraction efficiency would be increased while the threshold for grey level adjustment increased. Then the change of Signal to Noise Ratio (SNR) of reconstructed image was analyzed. It is found that the SNR will increase at first and then decrease with the increase of the threshold. The hologram with high diffraction efficiency and high SNR can be obtained if the special threshold for grey level adjustment is selected. The computer simulation and optical reconstruction of digital hologram prove the analysis.

Aug. 23, 2021
  • Vol. 40 Issue 3 327 (2011)
  • XU Fuyang, LI Yong, and GAO Zhiqiang

    To improve the spatial light modulation properties of Digital Micromirror Device (DMD),and exert its performance in holographic display and threedimensional reconstruction,blazing characteristics of DMD was investigated.Wtith the theory of reflection grating and DMD microstructur,it was concluded that there were four relative blazing states of DMD according to theoretical calculations and experimental results.And it was drawn that incident angle of 24° as usually demanded was the least angle of blazing angles.Thus the incident angle could be adjusted properly to change the blazing states of DMD and enhance the visual effects of the holographic representation.Finally,Fourier transform holography display was investigated as an application example,and the experimental results agree well with the theoretical analysis.

    Aug. 23, 2021
  • Vol. 40 Issue 3 332 (2011)
  • WANG Zhijun, LI Panlai, YANG Zhiping, and GUO Qinglin

    KBaPO4∶Eu3+ phosphor was synthesized by the high temperature solid state reaction method, and the effects of Eu3+ concentration and charge compensators on the luminescent characteristics of the phosphor were investigated. The phase present of the samples was characterized by powder Xray diffraction (XRD) (D/maxrA, Cu Kα, 40 kV, 40 mA, λ=0.15406 nm). The excitation and emission spectra of these phosphors were measured by a SHIMADZU RF540 fluorescence spectrophotometer. The research results show that under 400 nm excitation, the phosphor presents several emission peaks, which correspond to the 5D0→7FJ(J=0,1,2,3,4) transition of Eu3+, respectively, and the highest emission locate at 621 nm; monitored at 621 nm emission, the excitation spectrum contains 200~350 nm and 350~450 nm two excitation bands, which correspond to a weak charge transition broad band absorption CTS and a strong ff transition absorption of Eu3+, respectively, and the highest peak locates at 400 nm; the emission intensity of the phosphor was influenced by the Eu3+ concentration, and it reaches the maximum at 5 mol% Eu3+; the concentration quenching occurs when the Eu3+ concentration is beyond 5 mol%, and the concentration selfquenching mechanisms are the dd interaction by Dexter theory; under the conditions of charge compensator incorporated in the phosphor, the emission intensity can be enhanced, and can obtain the prime function with doping Li+ or Cl.

    Aug. 23, 2021
  • Vol. 40 Issue 3 336 (2011)
  • FAN Yexia, XIA feifei, YU Zemin, HOU Jun, and TIAN Chongjun

    The Ho3+/Yb3+codoped TiO2 sol was prepared through SolGel method, Ti(OC4H9)4 was chosen as a precursor, and ethanol as impregnant, acid as catalyzer, and its upxonverted luminescence mechanism was studyed. By means of Xray diffraction, energy spectrum and scanning electron microscope samples characterization, and the results show that the structure of the sample is rutile, samples contained by powder doped Yb, sample Ho and element of very small particles diameter is about 100 nanometers, spherical shape, and has obvious reunion phenomenon. At room temperature for 980 nm wavelength selection center, maximum output power for the diode laser 500 mV do stimulate light stimulates samples. In TiO2∶Ho3+ / Yb3+ sample find red and green, the emission strength of red is two times of green. When the doping concentration of Yb3+ is 2.5 mol%, fluorescence spectroscopy 543 nm conversion in observed strong green emission.The mechanisms of the upconversion luminescence were researched.

    Aug. 23, 2021
  • Vol. 40 Issue 3 340 (2011)
  • XU Kuanhong, LIANG YanMei, WANG JinYi, WANG YinLi, and ZHU XiaoNong

    The effect of beat noise in a time domain optical coherence tomography (OCT) system was investigated through theoretical analysis and their comparision with experimental data. It is shown that the best SNR of a fiberbased and balanced OCT system is about 100 dB, being restricted by the beat noise. And, the excess intensity noise may not be eliminated completely in a practical balanced OCT system, and this leads to a SNR value of 10~20 dB lower than the theoretically expected value. A simplified physical model that describes the overall noise of a time domain OCT system was established. By using such a model, the influence of the optical interferemeter, signal filtering and amplifier circuits, the resolution of data acquisition system and the external electromegnetic interference source were analyzed on the overall signaltonoise raitio of a practical optical coherence tomographic system, presenting a useful method to optimize the performance of the interested OCT system.

    Aug. 23, 2021
  • Vol. 40 Issue 3 344 (2011)
  • WANG Qionghua, PAN Dongdong, LI Xiaofang, LI Dahai, and LIAO Yongchuan

    A method was proposed to evaluate visual fatigue in autostereoscopic displays by measuring the pupil diameter of viewers.And a pupil diameter measuring device was presented to record the viewers′ pupil diameter when the viewers watch threedimensional videos.The conclusion was made that the degree of visual fatigue increases as the increase of viewing time according to viewers′ subjective evaluation,and experiments shown that the pupil diameter increases as the increase of the degree of visual fatigue.As a result,the pupil diameter can be used as a new measurement index of visual fatigue.The variation of viewers′ pupil diameter is 0.4 mm when viewers′ visual fatigue is medium which can be considered as a critical value of viewing comfort.

    Aug. 23, 2021
  • Vol. 40 Issue 3 350 (2011)
  • SONG Jidong, ZHANG Wanzhen, and LIN Bin

    In the process of cutting quartz,machining errors often cause two surfaces unparallel,which will can influence on the judgment to its crystal orientation.The angle measurement of fullautomated xray sorting machine was analyzed.The light spots deflected by quartz were detected by position sensitive detector,and relational expression between points position sensitive detector detected in the coordination and angles between top and bottom surfaces was deduced.And,the shapes of the light spots on the position sensitive detector in different incident angles and thicknesses were studied.It was found that similar linear relationship exists between height differences at coordination axis on position sensitive detector.When the incident angle is 20°,the norm of residual has the smallest value of 5.306 2×10-6 mm.The system resolution and measurement range are 1.033″ and 15′ respectively.

    Aug. 23, 2021
  • Vol. 40 Issue 3 354 (2011)
  • LI Peng, FENG Lishuang, CHEN Shuying, and WANG Kai

    The application of photonic crystal as micromirrors was emphatically investigated to calculate the photonic crystal band structure and band gap map, based on plane wave expansion method. The finitedifference timedomain was applied for analyzing the transmission characteristics of micromirrors constituted of the triangular lattice of dielectric cylinder structure to discuss the dielectric cylinder radius and lattice period effects on the reflectivity, and optimal results and parameters Were given. Photonic crystal ring resonant cavity constituted of dielectric cylinder can achieve monolithic integration, and realize the transmission of light in the air to substantially reduce the Kerr and Faraday effect, and the back scattering effects, etc. This study provides a new idea for highprecision resonant Gyro.

    Aug. 23, 2021
  • Vol. 40 Issue 3 358 (2011)
  • LIU Binghui, YANG Lijun, WANG Yang, and YUAN Julong

    In order to reveal the nearfield distribution of electromagnetic field and the axial distribution of trapping force acting on nanoparticles located in nearfield optical tweezers,and to explore the trapping size,trapping location and trapping stability,the direct calculations of Maxwell stress tensor were solved numerically by using threedimensional finite difference time domain method without the limitation of dipole approximation.Calculations show that the particle with radius larger than the aperture is pushed away from the tapered metalcoated fiber probe,while it tends to be trapped in larger effective region as the radius becoming smaller.The nearfield optical probe can trap and manipulate a nanoparticle with tens of nanometres diameter to different positions with different distance from the probe tip.Results of the calculations are found to be helpful for the design and manifacturing of nearfield optical tweezers system.验室开放基金项目(No.2009EP012)和机器人技术与系统国家重点实验室开放研究项目(No.SKLRS20102D10)资助

    Aug. 23, 2021
  • Vol. 40 Issue 3 363 (2011)
  • HE Xiaoqing, ZHANG Zhenhui, GAO Aihua, YE Ping, HU Shangbin, and LU Zhiguo

    The gain characteristics of laser gyro were investigated by measuring the relative strength of the laser gyro′s side spectrum. It was obtained experimentally that the gain of the laser gyro increases with the increasing of the current, the gyro gain presents the saturated gain phenomena with the increasing of the total pressure and the gain reaches a maximum value when the total pressure is about equal to 4P0. By comparing the timevarying gain curves of aluminum cathode and B cathode gyroscope in the gyro′s startup phase and corrying out error analysis of experimental data, the experimental results show that the gain stability and antienvironmental interference capability of B cathode gyro are better than that of aluminum cathode gyro. The gain of active medium and the beat′s frequency shift induced by the Langmuir flow effects both are related to the population density difference of the producing laser′s upper and lower level. The experimental results show that the zero drift′s stability of the laser gyro can be evaluated by the gyro gain′s stability.

    Aug. 23, 2021
  • Vol. 40 Issue 3 370 (2011)
  • HU Qiang, YAN Jizhong, and CHEN Linfeng

    Based on 4×4 matrix including meridian and latitude, the roundtrip matrix of nonplanar cavity was established. According to the matrix, the q parameters matrix was calculated, the complex astigmatism in some nonplanar cavity ring laser gyro (RLG) was analyzed, and the spot radius of Gaussian beam at any location was obtained theoretically. Then the spot radii of the outcavity Gaussian beam were measured by CCD, and the Gaussian beam waist was obtained by hyperbola fitting. The result was consistent with the theoretical one. According to spot radii, diaphragm radii and location, the diffraction loss was obtained. The designed diaphragm located at the Gaussian beam waist is circular, and the ratio of diaphragm radius to waist radius is about 2. The designed scheme guarantees the nonplanar cavity RLG works with single TEM00 mode.

    Aug. 23, 2021
  • Vol. 40 Issue 3 375 (2011)
  • WANG Xiangxin, LI Lin, and LI Lan

    Producing the broad XUV spectra is an important way to generate the isolated attosecond pulse, in which the propagation effect is an important factor. With the first order propagation equation of the slowlyevolvingwave approximation, the propagation effect on the broad XUV continuum spectra and the isolated attosecond pulse generated by twocolor fewcycle laser pulse were investigated. By simulating the generation of the broad XUV spectra under different focal positions and different medium lengths, it was found that it is benefit for the generation of the continuum spectra when the medium is after the focal point. But, with the longer medium, the pulse duration of the isolated attosecond pulse will be longer, although its intensity becomes higher. With further analysis, it was found that if the delay between twocolor pulses can be optimized, a strong isolated attosecond pulse with the same pulse duration as that of the singleactive electron model can still be obtained.

    Aug. 23, 2021
  • Vol. 40 Issue 3 379 (2011)
  • HE Ning, LIANG Po, and YU Shengyun

    According to the influence of arc discharge on safe operation of electrical equipment caused by quality defects or poor contact, the mechanism and detection methods of arc were analyzed. According to the characteristics of UV intensity radiation, an arc detecting system based on channel photomultipliers was designed. The captured arc discharge intensity was monitored, as a judgment basis of arc discharge degree, to realize the protection and control of electrical equipments effectively. The results show that the system can detect weak UV light with high sensitivity and linearity, and achieve the online monitoring of weak UV light detection.

    Aug. 23, 2021
  • Vol. 40 Issue 3 383 (2011)
  • DONG Hongjun, and ZHOU Zhongliang

    In view of the problem of solar radiation in the imaging spacebased laser warning system, the effects of sunlight on the infrared detector of warning system were studied by theoretical analysis and numerical calculation. On the basis of analysis of the different spatial relationship of sun and detector, the influences of direct sunlight and sunlight reflected by earth to the signal to noise ratio(SNR) of infrared image, laser threat detection, the detector safety were investigated respectively. The results show that the sunlight is the mainly background radiation to spacebased laser warning system. The sunlight reflected by earth is the main imaging background light of system′s near infrared detector, and the maximum energy density of reflected sunlight exposuring the CCD is 0.97 mJ/cm2. In the reflected sunlight background, the SNR of attack laser image exceeds 103, for the beacon laser is always below 1. While the reflected sunlight has no effect on attack laser detection, but it is strong background interference to the beacon laser detection. The sunlight direct exposure detector is unavoidable to the warning system. As the maximum energy density of the sun imaging spot is about 20 W/cm2, it will lead to the pixel of CCD saturation or even damaged. Since the imaging spot of sun is similar to the laser, direct sunlight will cause serious false alarm.

    Aug. 23, 2021
  • Vol. 40 Issue 3 388 (2011)
  • SUN Ping, LIU Bin, WANG Xiaofeng, and HAN Qing

    In electronic speckleshearing interferometry, it is difficult to realize phaseshifting by separating two birefracting beams. The phaseshifting method of the translating Wollaston prism can introduce additional phase changes without separating the two beams. The principle of the phase changes introduced by translating Wollaston prism was discussed. The relationship between the magnitude of translation and the additional phase was offered. A typical experiment about the method presented was completed by using a centrally loaded clamped circular plate. The obtained results show that the translating Wollaston prism method of phaseshift can effectively obtain displacement derivative field from fringe patterns of a test object.

    Aug. 23, 2021
  • Vol. 40 Issue 3 393 (2011)
  • ZHANG Zhifeng, JIANG Fengchun, YANG Kun, and REN Yufen

    The cotton′s maturity and fineness are the key parameters to evaluate the cotton fibers quality. The indirect parameters measurement can not accurately evaluate the cotton fiber′s quality. A direct method based on the optoelectronic measurement of Fraunhofer diffraction was presented. The measurement results were compared between the microscope and the optoelectronic setup. The results show that two methods have the good correlation(R=0.956, and SD=0.332). The optoelectronic technique can assess the cotton fiber′s maturity in the lab.

    Aug. 23, 2021
  • Vol. 40 Issue 3 397 (2011)
  • HAN Yishi, ZHANG Li, and CHEN Weitao

    A bidirectional radiooverfiber system using a single light source was demonstrated. A tunable laser was simply configured to produce the constant frequency laser source at central station(CS), and the baseband signal was modulated in optical carrier through integrated optical modulation technology(frequency modulation, intensity modulation), eventually forming a 60 GHz millimeterwave downlink signal. And, the same optical carrier was reused at base station for uplink connection. The system combined the characteristics of optical carrier reuse technology and integrated optical modulation technology, so as to use resources reasonably and simplify the base station structure. Simulation result shows that the bidirectional 2.5Gbit/s data is successfully transmitted over 20 km singlemode fiber for both upstream and downstream channels with less than 0.5dB power penalty. Relative to the existing technical scheme, the transmission system has advantages in the transmission power, the transmission distance and transmission performance.

    Aug. 23, 2021
  • Vol. 40 Issue 3 401 (2011)
  • HU Xiaodong, PENG Lang, LEI Ming, LEI Yusheng, XIONG Mengfei, and XIONG Muxue

    A subdividing method for grating signal based on FPGA was proposed. The method uses CORDIC algorithms and singleprecision floatingpoint calculation, which can implement the function of directionjudgement,counting, phase decoding by CORDIC algorithm, floatingpoint calculation between the two codes on a single FPGA. It can assure the subdivision accuracy, guarantee the effective calculation accuracy of subdivision data, and ensure the computational speed. The simulation was based on chip CycloneIIEP2C20F484C8 of Altera company, by subdividing the signal of grating with 2 μm length period. The result proves the feasibility and validity of this method.

    Aug. 23, 2021
  • Vol. 40 Issue 3 407 (2011)
  • YAO Ruia, ZHANG Yanninga, SUN Jinqiub, and ZHANG Yongpenga

    When the frame transfer CCD image sensor shooting starsky background image,the smear phenomenon caused by high brightness stars in the field of view will seriously affect the target detection.For removing the smear phenomenon,a smear removal algorithm based on wavelet transform in starsky image was proposed.According to the mechanism of smear and characteristics of the starsky image,the model of smear problem was established,the smear line was separated into the high frequency components and vertical components by using multilayer twodimension haar wavelet transform,and the smearremoved image was reconstructed.The expirmental results show that the method can effectively remove smear and retain original image information,and enhance the SNR of small target in smear area.

    Aug. 23, 2021
  • Vol. 40 Issue 3 413 (2011)
  • MING Ming, WANG Jianli, and MA Peili

    As a frequent part of optical systems, the lens group plays an important role in the large aperture optical system, but the lens group can not be tested directly after alignment. The disadvantage during common measurement of the lens group was analyzed. With adding one simple optical element, a new method for testing the whole lens group after alignment, which solves the test problem of lens group applied in the large aperture optic systems. Two practical optical systems were given, and the design and accuracy demand of the lens group were analyzed. Next, the lens group of the practical optical systems with the new method were tested, and the comparison of analyzed results and test results proved the reliability and precision of this method, which derives that the precision of measurement is better than 0.01λ. At last, the optical quality of lens group after final alignment meets the design requirement.

    Aug. 23, 2021
  • Vol. 40 Issue 3 419 (2011)
  • LIAO Zhibo, JIAO Wenchun, and FU Ruimin

    In the camera design,veiling glare index is a main criterion to evaluate the stay light.In order to quickly,easily and accurately calculate the veiling glare index,the stray light paths were detailed analyzed.The formula of fastcalculating the veiling glare index was deduced and programmed.It was indicated that the proposed method is an easy way to estimate the veiling glare index and it will betterment the following design.

    Aug. 23, 2021
  • Vol. 40 Issue 3 424 (2011)
  • WANG Shuang, HUANG Min, and ZHU Qibing

    Partial least squares projection analysis combined with uninformative variable elimination was used to select optimal wavelengths from apple hyperspectral scattering images.After this algorithm,the number of effectivewavelengths decreased to 26%. The selected effective wavelengths were set as inputs of partial least squares model. Root mean square error of prediction dropped from 6.00N to 5.73N and correlation coefficient increased a little. The result shows that to select effective wavelengths using the algorithm is feasible. In the parameter selection, there is not such as random defects. It is expected that the algorithm would provide an effective method foroptimal wavelengths selection using hyperspectral scattering image technique.

    Aug. 23, 2021
  • Vol. 40 Issue 3 428 (2011)
  • HOU QingYua, WU ChunFengb, ZHAO Minga, LU LiHonga, and ZHANG Weia

    In order to realize automatic image registration for infrared image and visible image,an image registration algorithm based on the steepest descent of the likelihood function was proposed.Image edge was selected as the registration point,and thus the image registration was transferred to edge point set registration.The likelihood function of edge sets registration was established on the basis of Gauss Mixture Model (GMM) of point sets.In order to resolve the optimum transformation parameter by using the steepest descent method,the likelihood function was regarded as objective function and the affine transformation parameter was regarded as the optimization variance.Meanwhile,the multiresolution pyramid was induced into iteration registration and the speed of registration algorithm for high resolution image was increased.The experiment results show that the algorithm can well complete automatic registration of infrared image and visual image at high registration accuracy and fast registration speed.

    Aug. 23, 2021
  • Vol. 40 Issue 3 433 (2011)
  • WU Yingxia, ZHANG Jianqi, YANG Hongjian, WANG Xiaobing, and WANG Xiaorui

    The apparent average temperature difference and critical dimension of actual target and background were acquired through retrieving infrared target image.The retrieved apparent temperature difference and the measured MRTD curve were combined to determine the corresponding spacial frequency.And,a quantitative relationship between the target infrared image and the probability of detection and recognition was established with Johnson criteria and target transfer probability function(TTPF).The method avoids operater′s subjective judging,so the result is more impersonal.This method was experimentally validated in evaluating the detection and recognition probability of IR system.

    Aug. 23, 2021
  • Vol. 40 Issue 3 438 (2011)
  • REN Taotao, TIAN Yongyong, XIE Yun, and CHEN Wuling

    HeNa laser(λ=632.8 nm,P=12 mW) &licl was used to irradiate B.subtilis WB3 which had an antagonistic ability on Botrytis cinerea.14 strains that have prominent antagonistic effects were obtained,and the maximum inhibitory bandwidth is 15.7 mm.According to the mortality rates and the size of antagonistic of single mutagenesis group,the optimization condition of irradiation time of 30 min and the density of licl of 1.2% were obtained.After multiplicity mutation,the max inhibiting belt width is L8 that raised more than 14%,however single HeNe laser and licl irradiation could only raise 8.8% and 9%.The strains grew rapidly with stable heredity.The proposed experimental results the HeNa laser & licl mutagenesis of Bacillus subtilistest WB3 show a broad application prospect for the biological control of botrytis cinerea.

    Aug. 23, 2021
  • Vol. 40 Issue 3 443 (2011)
  • LI Ke, LING Weijun, and WANG Zhijiang

    The entropy properties of the light field of coupled identical Λtype threelevel atoms interacting with vacuum field in cavity filled with Kerr medium were investigated by means of quantum theory.The time evolutions of the entropy of the light field were discussed via the initial state of the system,detuning,coupling coefficient between the atoms,and the Kerr coefficient.Numerical calculation results show that the evolution of the entropy of the light field exhibits periodic oscillation,and its frequency and amplitude are intensively dependent on the initial state of the system.When the detuning the oscillation amplitude decreases with the increases of coupling strength and Kerr coefficient.

    Aug. 23, 2021
  • Vol. 40 Issue 3 448 (2011)
  • JIANG Min, WU Yunwen, PENG Jun, YI Jian, and LI Xiaojuan

    With two atoms system drived by external periodic laster field, we have getted the analytic solutions of the centroid quantum state transition probability of the system via the perturbation theory. In the case of two Ca+, the figure of the transition probability of the photon states have simulated, which is vary with the time and the frequency of the laser. The results show that the quantum state of centerofmass collapses and revives,adjusted by external periodical laser frequency and interaction time under feeble field.When the frequency offset is selected from to ,the quantum state of centerofmass transition probabilities achieve 0.98,the longest manipulation cycle is shortened to 0.6×10-6 s,and the manipulation cycle is shortened greatly in theory.When the frequency offset achieve 1.2×107 Hz,quantum state of centerofmass transition probabilities is about 0.49,and the laser can not effectively manipulate the transition of centerofmass quantum states.Accordingly,these results may have some referential values on the realization of twobit quantum logic gate implementation and some other experimental studies.

    Aug. 23, 2021
  • Vol. 40 Issue 3 453 (2011)
  • LIU Xiaojuan, LIU Yiman, and LIU Min

    In the rotatingwave approximation,the evolution of the field quantum entropy in the system that consists of a twolevel atom interacting with a singlemode field was studied,considering the atomic motion and the field frequency varying with the time in the form of sinefunction at the same time.In two cases of neglecting atomic motion and considering atomic motion,figures of the time evolutions of the field entropy were plotted respectively using numerical calculations.Influences of the atomic motion,the fieldmodel structure parameter,amplitude and angular frequency of the fieldfrequency variation on the field entropy were also discussed.The atomfield entangled states,field fock states and atomic high fidelity states were prepared by analytic method according to the decomposition theorem of Schmidt,and the related system parameters of these quantum states operation were acquired.The results show that:the time evolution behavior of the field entropy is modulated by the frequency variation of field; the interaction between the field and atom will weaken with the increase of the amplitude of variation of the field frequency; the period of the field entropy agrees with the period of fieldfrequency variation; the atomic motion will result in the period of the field entropy doubled; the evolution of the field entropy is related to the parity of fieldmode structure parameter; the approximate EPR states of fieldatom can be prepared periodically whether the atom moves or not.

    Aug. 23, 2021
  • Vol. 40 Issue 3 458 (2011)
  • PENG Jun, WU Yunwen, and LI Xiaojuan

    A theory scheme was proposed for implementing a Toffoli gate with threelevel structure superconducting quantuminterference devices (SQUID), based on the cavity quantum electrodynamics (CQED). In this proposal, quantum information was encoded into the two lower levels of a SQUID while a higher level serves as the gate manipulation. Applying the coupling of the cavity field with a SQUID, which was driven by a classical microwave pulse to control the evolution of quantum state, the scheme could be extended to achieve Nqubit Toffoli gate. And, the experimental feasibility of Toffoli gate was disscussed, and the total operation time of fourqubit Toffoli gate was computed only 30 nanometers, which was much shorter than the decay time of the cavity mode or the energy relaxation time of the higher level. And the increasing rate of the gate response time became slow with the increase of the qubit number.

    Aug. 23, 2021
  • Vol. 40 Issue 3 466 (2011)
  • XU Yunxi, JIANG Yunliang, and CHEN Fang

    The scene matching aided inertial integrated navigation system needs to get both the aircraft position errors and the course deviation relative to the present flight path simultaneously.A realtime scene matching algorithm based on region covariance was proposed.The distance of region covariance matrixs as the similarity measuring for image matching was introduced.Firstly,the image was smoothed by a Gaussion filter,and features of the image were extracted.Global searching algorithm using multilevel pyramid matching was put forward.Then,multiple local regions in real image was selected,and local searching and matching was utilized.The local match set between real image and referance image was obtained.Finally,the least square algorithm ans RANSAC method were applied to get the distortion transformation parameters between real image and referance image.The results of simulation show that the proposed image matching algorithm can satisfy the accuracy demands of scene aided navigation system and provide the system location and course errorcorrecting information.

    Aug. 23, 2021
  • Vol. 40 Issue 3 471 (2011)
  • QIN Jian, CHEN Qian, and QIAN Weixian

    In connection with the infrared target detecting under complex cloud backgrounds,a small target detection algorithm based on the optical flow estimation and adaptive was put forward.Fistly,the infrared image under cloud backgrounds was analyzed based on the optical flow and the cloud movement was extracted.The traditional gradientbased optical flow was proved based on the characteristics of cloud movement and the two constraints of the optical flow equation in the calculation of optical flow.And,it was found that the cloud movement had a greater impact on the target detection,the algorithm of adaptive suppress the complex backgrounds was introduced to reduce the interference of the cloud.the background factors on behalf of background complexity was used to adjust the threshold in the cloud region extracted in the optical flow analysis.In this way,the background suppresion was produced in the cloud movements.It would easily cause false alarm and the algorithm simply the calculation,and reduce the influence of the cloud and the false alarm.Experimental results show that this algorithm can detect small targets and significantly reduce the false alarm caused by the cloud area.

    Aug. 23, 2021
  • Vol. 40 Issue 3 476 (2011)
  • CHEN Jun, CUI Xiangxia, XIAO Jing, YANG Zhaohua, and LIU Tingting

    The properties of edge enhancement for different marginal distribution density image based on radial Hilbert transform with a spiral phase filter were studied.The analytical expression to describe the point spread function of a finiteradius spiral phase filter with topological charge n=1 was given and the edge enhancement for different marginal distribution image such as circular aperture,Chinese character and portraits were simulated.The results show that the edge enhanced images using radial Hilbert transform have threedimensional relief effect,and the more intensive marginal distribution of input image,the more significant relief effect.Theoretical analysis found that this property derives from convolution between the input image and subsidiary maximum in the point spread function.This conclusion will be beneficial as a way for image processing.

    Aug. 23, 2021
  • Vol. 40 Issue 3 483 (2011)
  • Please enter the answer below before you can view the full text.
    6+1=
    Submit