Journals >Acta Photonica Sinica
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2011
Volume: 40 Issue 3
32 Article(s)
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Research Article
Relationship of Image Quality of Digital Hologram and Grey Level Adjustment
GAO Zhiqiang, 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 doIt 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 327 (2011)
Blazing Characteristics of DMD and Its Applications in Holographic Display
XU Fuyang, LI Yong, and GAO Zhiqiang
To improve the spatial light modulation properties of Digital Micromirror Device (DMD),and exert its performance in holographic display and threedimensional reconstruction,blazing characteristics of DMD was investigated.Wtith the theory of reflection grating and DMD microstructur,it was concluded that there were four To improve the spatial light modulation properties of Digital Micromirror Device (DMD),and exert its performance in holographic display and threedimensional 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 332 (2011)
Spectral Characteristics of KBaPO4∶Eu3+ Red Emitting Phosphor
WANG Zhijun, LI Panlai, YANG Zhiping, and GUO Qinglin
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 Xray diffraction (XRD) (D/maxrA, CuKBaPO4∶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 Xray diffraction (XRD) (D/maxrA, Cu Kα, 40 kV, 40 mA, λ=0.15406 nm). The excitation and emission spectra of these phosphors were measured by a SHIMADZU RF540 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 ff 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 selfquenching mechanisms are the dd 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 336 (2011)
Effect of the Yb3+Concentration in Upconverting of Ho3+/Yb3+ Codoped TiO2
FAN Yexia, XIA feifei, YU Zemin, HOU Jun, and TIAN Chongjun
The Ho3+/Yb3+codoped TiO2 sol was prepared through SolGel 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 Xray diffraction, energy spectrum and scanning electron microscope samples characterization, and thThe Ho3+/Yb3+codoped TiO2 sol was prepared through SolGel 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 Xray 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 340 (2011)
Noise Analysis and Experimental Study of Time Domain Optical Coherence Tomography
XU Kuanhong, LIANG YanMei, WANG JinYi, WANG YinLi, and ZHU XiaoNong
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 fiberbased and balanced OCT system is about 100 dB, being restricted by the beat noise. And, the excess inteThe 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 fiberbased 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 signaltonoise raitio of a practical optical coherence tomographic system, presenting a useful method to optimize the performance of the interested OCT system..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 344 (2011)
Relation Between Viewer′s Pupil Diameter and Visual Fatigue in Autostereoscopic Display
WANG Qionghua, PAN Dongdong, LI Xiaofang, LI Dahai, and LIAO Yongchuan
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 threedimensional videos.The conclusion was made that the degree of visual fatigue incA 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 threedimensional 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 350 (2011)
A New Optical Angle Measurement and Compensation
SONG Jidong, ZHANG Wanzhen, 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 fullautomated xray sorting machine was analyzed.The light spots deflected by quartz were detected by position sensitive detector,and relatiIn 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 fullautomated xray 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 354 (2011)
Design of Photonic Crystal Micromirrors in Ring Resonant Cavity
LI Peng, FENG Lishuang, CHEN Shuying, and WANG Kai
The application of photonic crystal as micromirrors was emphatically investigated to calculate the photonic crystal band structure and band gap map, based on plane wave expansion method. The finitedifference timedomain was applied for analyzing the transmission characteristics of micromirrors constituted of the triThe application of photonic crystal as micromirrors was emphatically investigated to calculate the photonic crystal band structure and band gap map, based on plane wave expansion method. The finitedifference timedomain was applied for analyzing the transmission characteristics of micromirrors 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 highprecision resonant Gyro..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 358 (2011)
Nanomanipulation of Nearfield Optical Tweezers Using a Fiber Probe
LIU Binghui, YANG Lijun, WANG Yang, and YUAN Julong
In order to reveal the nearfield distribution of electromagnetic field and the axial distribution of trapping force acting on nanoparticles located in nearfield optical tweezers,and to explore the trapping size,trapping location and trapping stability,the direct calculations of Maxwell stress tensor were solved numeIn order to reveal the nearfield distribution of electromagnetic field and the axial distribution of trapping force acting on nanoparticles located in nearfield 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 threedimensional 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 metalcoated fiber probe,while it tends to be trapped in larger effective region as the radius becoming smaller.The nearfield optical probe can trap and manipulate a nanoparticle 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 nearfield 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.SKLRS20102D10)资助.
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 363 (2011)
Experimental Investigation on the Gain Characteristics of Laser Gyro
HE Xiaoqing, ZHANG Zhenhui, GAO Aihua, YE Ping, HU Shangbin, and LU Zhiguo
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 totalThe 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 timevarying gain curves of aluminum cathode and B cathode gyroscope in the gyro′s startup phase and corrying out error analysis of experimental data, the experimental results show that the gain stability and antienvironmental 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 370 (2011)
Study on the Complex Astigmatism in Nonplanar Cavity RLG and Design of the Diaphragm
HU Qiang, YAN Jizhong, and CHEN Linfeng
Based on 4×4 matrix including meridian and latitude, the roundtrip 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 Based on 4×4 matrix including meridian and latitude, the roundtrip 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 outcavity 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 375 (2011)
Propagation Effect on the Broadbandwidth XUV Continuum Spectra
WANG Xiangxin, 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 slowlyevolvingwave approximation, the propagation effect on the broad XUV continuum spectra and the isolated attoseconProducing 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 slowlyevolvingwave approximation, the propagation effect on the broad XUV continuum spectra and the isolated attosecond pulse generated by twocolor fewcycle 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 twocolor pulses can be optimized, a strong isolated attosecond pulse with the same pulse duration as that of the singleactive electron model can still be obtained..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 379 (2011)
Arc Discharge Detection Based on Channel Photomultipliers
HE Ning, LIANG Po, and YU Shengyun
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. TAccording 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 online monitoring of weak UV light detection..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 383 (2011)
Effects of Sun on Imaging SpaceBased Laser Detection System
DONG Hongjun, and ZHOU Zhongliang
In view of the problem of solar radiation in the imaging spacebased 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 influencesIn view of the problem of solar radiation in the imaging spacebased 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 spacebased 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 388 (2011)
Phaseshifting Method of Translating Wollaston Prism in Electronic Speckleshearing Interferometry
SUN Ping, LIU Bin, WANG Xiaofeng, and HAN Qing
In electronic speckleshearing interferometry, it is difficult to realize phaseshifting by separating two birefracting beams. The phaseshifting method of the translating Wollaston prism can introduce additional phase changes without separating the two beams. The principle of the phase changes introduced by translatinIn electronic speckleshearing interferometry, it is difficult to realize phaseshifting by separating two birefracting beams. The phaseshifting 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 phaseshift can effectively obtain displacement derivative field from fringe patterns of a test object..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 393 (2011)
A Novel Method to Assess Cotton Fiber Fineness and Maturity Based on Optoelectronic Measurement
ZHANG Zhifeng, JIANG Fengchun, YANG Kun, and REN Yufen
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 compaThe 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 397 (2011)
Bidirectional Radio over Fiber System Based on Integrated Optical Modulation
HAN Yishi, ZHANG Li, and CHEN Weitao
A bidirectional radiooverfiber 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 modulatiA bidirectional radiooverfiber 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 millimeterwave 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 bidirectional 2.5Gbit/s data is successfully transmitted over 20 km singlemode 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 401 (2011)
Realization of a Subdividing Method for Grating Signal Based on FPGA
HU Xiaodong, PENG Lang, LEI Ming, LEI Yusheng, XIONG Mengfei, and XIONG Muxue
A subdividing method for grating signal based on FPGA was proposed. The method uses CORDIC algorithms and singleprecision floatingpoint calculation, which can implement the function of directionjudgement,counting, phase decoding by CORDIC algorithm, floatingpoint calculation between the two codes on a single FPGA. A subdividing method for grating signal based on FPGA was proposed. The method uses CORDIC algorithms and singleprecision floatingpoint calculation, which can implement the function of directionjudgement,counting, phase decoding by CORDIC algorithm, floatingpoint 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 CycloneIIEP2C20F484C8 of Altera company, by subdividing the signal of grating with 2 μm length period. The result proves the feasibility and validity of this method..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 407 (2011)
Smear Removal Algorithm of CCD Imaging SensorsBased on Wavelet Transform in Starsky Image
YAO Ruia, ZHANG Yanninga, SUN Jinqiub, and ZHANG Yongpenga
When the frame transfer CCD image sensor shooting starsky 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 starsky image was proposed.AccordingWhen the frame transfer CCD image sensor shooting starsky 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 starsky image was proposed.According to the mechanism of smear and characteristics of the starsky image,the model of smear problem was established,the smear line was separated into the high frequency components and vertical components by using multilayer twodimension haar wavelet transform,and the smearremoved 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 413 (2011)
A New Method for Testing the Whole Lens Group of Large Optic System
MING Ming, WANG Jianli, and MA Peili
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 tAs 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 419 (2011)
Veiling Glare Index Calculation for Refract Optical System
LIAO Zhibo, JIAO Wenchun, and FU Ruimin
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 fastcalculating the veiling glare index was deduced and programmed.It was indicated that the prIn 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 fastcalculating 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 424 (2011)
Optimal Wavelength Selection of Hyperspectral Scattering Images Based o UVEPLS Projection Analysis
WANG Shuang, HUANG Min, and ZHU Qibing
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 sqPartial 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 428 (2011)
IR/Visible Image Registration Based on the Steepest Descent of the Likelihood Function
HOU QingYua, WU ChunFengb, ZHAO Minga, LU LiHonga, 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.TheIn 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 multiresolution 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 433 (2011)
Application of Johnson Criteria in Evaluating Field Detection and Recognition Probability of IR System
WU Yingxia, ZHANG Jianqi, YANG Hongjian, WANG Xiaobing, and WANG Xiaorui
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 relationshThe 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 438 (2011)
Improvement of Antagonistic Activity of Bacteria WB3 Against Botrytis Cinerea by HeNe Laser and licl
REN Taotao, TIAN Yongyong, XIE Yun, and CHEN Wuling
HeNa 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 mutagHeNa 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 HeNe laser and licl irradiation could only raise 8.8% and 9%.The strains grew rapidly with stable heredity.The proposed experimental results the HeNa laser ＆ licl mutagenesis of Bacillus subtilistest WB3 show a broad application prospect for the biological control of botrytis cinerea..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 443 (2011)
Entropy Properties of the Field of Coupled Identical Λtype Threelevel Atoms Interacting with Vacuum Field in Cavity Filled with Kerr Medium
LI Ke, LING Weijun, and WANG Zhijiang
The entropy properties of the light field of coupled identical Λtype threelevel 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 The entropy properties of the light field of coupled identical Λtype threelevel 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 448 (2011)
Centerofmass Quantum States Motion of Two Ions Drived by Feeble Field
JIANG Min, WU Yunwen, PENG Jun, YI Jian, and LI Xiaojuan
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 tWith 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 centerofmass 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 centerofmass 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 centerofmass transition probabilities is about 0.49,and the laser can not effectively manipulate the transition of centerofmass quantum states.Accordingly,these results may have some referential values on the realization of twobit quantum logic gate implementation and some other experimental studies..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 453 (2011)
Evolution of the Field Entropy and Preparation of Quantum States in the Control of Atomic Motion and Fieldfrequency Variation
LIU Xiaojuan, LIU Yiman, and LIU Min
In the rotatingwave approximation,the evolution of the field quantum entropy in the system that consists of a twolevel atom interacting with a singlemode field was studied,considering the atomic motion and the field frequency varying with the time in the form of sinefunction at the same time.In two cases of neglectIn the rotatingwave approximation,the evolution of the field quantum entropy in the system that consists of a twolevel atom interacting with a singlemode field was studied,considering the atomic motion and the field frequency varying with the time in the form of sinefunction 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 fieldmodel structure parameter,amplitude and angular frequency of the fieldfrequency variation on the field entropy were also discussed.The atomfield 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 fieldfrequency 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 fieldmode structure parameter; the approximate EPR states of fieldatom can be prepared periodically whether the atom moves or not..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 458 (2011)
Realization of Toffoli Gate Based on Superconducting QuantumInterference Devices in Cavity Quantum Electrodynamics
PENG Jun, WU Yunwen, and LI Xiaojuan
A theory scheme was proposed for implementing a Toffoli gate with threelevel structure superconducting quantuminterference 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 gateA theory scheme was proposed for implementing a Toffoli gate with threelevel structure superconducting quantuminterference 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 Nqubit Toffoli gate. And, the experimental feasibility of Toffoli gate was disscussed, and the total operation time of fourqubit 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 466 (2011)
Scene Matching Algorithm Based on Region Covariance for INS Integrated Navigation System
XU Yunxi, JIANG Yunliang, 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 realtime scene matching algorithm based on region covariance was proposed.The distance of region covariance matrixs as the similariThe 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 realtime 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 multilevel 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 errorcorrecting information..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 471 (2011)
A Detection Algorithm for Dim and Small Infrared Target Based on the Optical Flow Estimation and the Adaptive Background Suppression
QIN Jian, CHEN Qian, and QIAN Weixian
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 traditioIn 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 gradientbased 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 476 (2011)
Properties of Image Edge Enhancement Using Radial Hilbert Transform
CHEN Jun, CUI Xiangxia, XIAO Jing, YANG Zhaohua, and LIU Tingting
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 finiteradius spiral phase filter with topological charge n=1 was given and the edge enhanceThe 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 finiteradius 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 threedimensional 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..
Acta Photonica Sinica
- Publication Date: Aug. 23, 2021
- Vol. 40, Issue 3, 483 (2011)
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