Journals >Acta Photonica Sinica
Contents
2013
Volume: 42 Issue 11
23 Article(s)
Export citation format
Research Article
Dispersion Slope Compensating Photonic Quasicrystal Fiber over S+C+L Band
LI Yuan, FAN Wande, CHEN Jun, BU Fanhua, and LI Haipeng
For multichannel dispersion compensation in dense wavelength division multiplexing (DWDM) systems optical communication networks, a broadband dispersion slope compensating photonic quasicrystal fiber (PQF) is proposed. The PQF has a sixfold symmetric quasiperiodic array of air holes in cladding and a high index robFor multichannel dispersion compensation in dense wavelength division multiplexing (DWDM) systems optical communication networks, a broadband dispersion slope compensating photonic quasicrystal fiber (PQF) is proposed. The PQF has a sixfold symmetric quasiperiodic array of air holes in cladding and a high index rob in the concentric core. The simulating results of the dispersion slope and dispersion of PQF reveal that the relative dispersion slope (RDS) can reach a low value 0.004 4 nm－1 to 0.002 9 nm－1 that is equal to the standard single mode fiber (SMF) over S+C+L band approximately; the PQF can achieve dispersion slope compensation effectively, while obtain a larger negative dispersion coefficient of －2 476 ps·nm－1·km－1 over optical communication band 1 460 nm to 1 625 nm. The value of dispersion compensation result is (－0.5~0)ps·nm－1·km－1 to the SMF in the S+C+L band. The designed PQF can achieve multichannel dispersion compensation, simplify the structure and reduce compensation costs, and then it can be used for wideband dispersion slope compensation..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1261 (2013)
Polarization Control Characteristics of Spun Magnetooptic Fibers
WU Bao jian, HAN Rui, WEN Feng, and QIU Kun
According to the coupledmode method, the propagation of guided optical waves in spun magnetooptic fibers (SMOFs) was investigated by considering the coupling of linear birefringence, fiber spun and the magnetooptic (MO) effect. The results show that, 1) the SMOF′s eigen optical waves are of constant ellipticity alonAccording to the coupledmode method, the propagation of guided optical waves in spun magnetooptic fibers (SMOFs) was investigated by considering the coupling of linear birefringence, fiber spun and the magnetooptic (MO) effect. The results show that, 1) the SMOF′s eigen optical waves are of constant ellipticity along the SMOF; 2) from the viewpoint of input/output properties, the SMOF may be regarded as a linearly birefringent MO fiber (LBMOF) followed by a polarization rotator, in which the LBMOF has the same length as the SMOF and its MO coupling coefficient is equal to that of the SMOF minus fiber rotation ratio. The polarization characteristics of the SMOF under magnetic control were analyzed as well. For the case of incident linear polarization, the ellipticity and azimuth of light output from the SMOF can be linearly adjusted by changing the MO coupling coefficient or magnetic field, which is helpful for the design of magnetically tunable polarization controllers..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1267 (2013)
Effect of Radiation Dose on Radiationinduced Attenuation and Temperature Dependence in Optical Fiber
JIN Jing, XU Raomei, LIU Jixun, and SONG Ningfang
The effect of total dose on radiationinduced attenuation and temperature dependence of radiationinduced attenuation in optical fibers was investigated. The GeP doped fibers were irradiated with different total doses and test systems for radiation induced attenuation and temperature dependence were built up. The relaThe effect of total dose on radiationinduced attenuation and temperature dependence of radiationinduced attenuation in optical fibers was investigated. The GeP doped fibers were irradiated with different total doses and test systems for radiation induced attenuation and temperature dependence were built up. The relation between radiation induced attenuation and radiation dose was analyzed. The results show that the radiation induced attenuation at 1 310 nm in fiber is primarily dependent on P1 center. The POHC center also has obviously effect on radiation induced attenuation at 1 310 nm irradiated at high dose. The radiation induced attenuation in fiber increases with increasing radiation dose. The radiation induced attenuation of irradiated GeP doped fibers after sufficient annealing exhibit steady and monotonic temperature dependence in the temperature range from －40 to 60℃. The higher radiation dose, the stronger temperature dependence of radiation induced attenuation in the irradiated fiber there will be. The investigation on total dose influencing radiation induced attenuation and temperature dependence in GeP codoped fibers can better apply the optical fiber in complex radiation environment and utilize stable temperature dependence of radiation induced attenuation for temperature sensor..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1272 (2013)
Multiuser MIMO Indoor Visible Light Communication System Based on BD Precoding Algorithm
HONG Yang, CHEN Jian, and WANG Zixiong
A precoding multiuser MIMO model was proposed for the multiuser indoor visible light communication system. The multiuser interference was eliminated by data preprocessing in transmitter, leading to the reduction of complexity and power consumption of terminals in the VLC system. Based on a 4×［2, 2］ indoor MUMA precoding multiuser MIMO model was proposed for the multiuser indoor visible light communication system. The multiuser interference was eliminated by data preprocessing in transmitter, leading to the reduction of complexity and power consumption of terminals in the VLC system. Based on a 4×［2, 2］ indoor MUMIMO VLC system, the limitation of block diagonalization precoding algorithm in VLC system was figured out. The corresponding solution by utilizing receivers with different field of view was analyzed. The impact of the terminals′ location to BER and SNR performances of the proposed system was also investigated. Based on the numerical results of the proposed indoor VLC system, the terminals can achieve 100 Mb/s at a BER of 10－6 in the most indoor area when single LED chip′s power is 10 mW..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1277 (2013)
Propagation Property of THz Pulses Through a Hollowcore Bragg Fiber with Cobwebby Cladding
ZHANG Baorong, and LI Bingxin
The coefficient of loss and dispersion relation of a hollowcore Bragg fiber with cobwebby cladding in the THz band was investigated analytically by adjustable boundary conditions Fourier decomposition method (ABCFDM). The spectra and waveforms for three THz transmitted pulses were calculated through the hollowcore BThe coefficient of loss and dispersion relation of a hollowcore Bragg fiber with cobwebby cladding in the THz band was investigated analytically by adjustable boundary conditions Fourier decomposition method (ABCFDM). The spectra and waveforms for three THz transmitted pulses were calculated through the hollowcore Bragg fiber. The analytical result shows that loss characteristic of the hollowcore Bragg fiber is similar to a highpass filter with variable cutoff frequency and phaseshift constant. Fiber core radius and transmission distance determinate the cutoff frequency of the highpass filters jointly. The hollowcore Bragg fiber only attenuates the THz wave in the band below the cutoff frequency, and significant phaseshift will be yield near the cutoff frequency when the THz pulse pass through the fiber. If the core radius is advisable, THz pulse will be transmitted through the hollowcore Bragg fiber effectively for a short distance..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1283 (2013)
Study and Fabrication of Low Loss Filter Film in Torpedo Fiber Optic Guidance System
TANG Haolong, FU Xiuhua, LIU Guojun, YANG Yongliang, and KOU Yang
To meet the torpedo fiber optic guidance system communication needs and achieve the information exchange between torpedo and ship, a kind of lowloss communication filter was designed and manufactured. The films were prepared by the depositing method of dual ion beam sputtering, through the comparative study of severalTo meet the torpedo fiber optic guidance system communication needs and achieve the information exchange between torpedo and ship, a kind of lowloss communication filter was designed and manufactured. The films were prepared by the depositing method of dual ion beam sputtering, through the comparative study of several targets. Based on the requirements of the lowloss filter, a new type of alloy target and SiO2 target were chosen as sputtering materials. In order to broaden the shortwave cutoff region of the filter, the longwave pass film was added behind the initial film, and the thicknesses of the matching layers were optimized, based on the concept of equivalent refractive index. The insertion loss of the passband of the filter was reduced by 0.12 dB. In the preparation of the film, the optical extreme value method and average time method were used to monitor layers′ thickness. By using the method of correct the thickness of irregular layers in proportion, the layers′ thickness control accuracy was improved. The proposed filter basically meets the demand of torpedo fiber optic guidance system through performance test..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1289 (2013)
Analysis of Laser Cleaning of Iron in Air Based on Characteristics of Plasma Spectra
YAO Hongbing, YU Wenlong, LI Yaru, GAO Yuan, MENG Chunmei, JIANG Guangping, and ZHANG Yongkang
The intensities of emission spectra of rusty iron plasma induced by Nd: YAG pluse laser, were experimentally studied in air atmosphere. Modified ME5000 echelle grating spectrometer coupled to intensified CCD camera was used to acquire the emission spectrum of laserinduced Fe plasma under the laser shock. The experimenThe intensities of emission spectra of rusty iron plasma induced by Nd: YAG pluse laser, were experimentally studied in air atmosphere. Modified ME5000 echelle grating spectrometer coupled to intensified CCD camera was used to acquire the emission spectrum of laserinduced Fe plasma under the laser shock. The experimental results indicated that continuous laser impacts with certain energy were required to induce the Fe emission spectrum due to the existence of the impurities in the sample. The relative intensities of plasma spectra increased obviously after the impurities were decomposed during the process of laser shock. With the comparison of spectra acquired under 1st laser shock and in the cleaning process, it was shown that when the intensity of the characteristic line at the wavelength of 563.40 nm increased by 443.11%, the rusty iron was cleaned and the cleaningratio reached 99.84%. At the same time, the fluctuation of the spectrum decreased obviously during the cleaning. As a result, the changes of spectrum distribution and relative intensity of Fe spectrum lines could be used to judge whether the samples were cleaned or not through an analysis of the spectrum lines under 1st laser shock and those in the cleaning process..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1295 (2013)
Comparative Analysis of the Trapping Force Using LaguerreGaussian Beam and Gaussian Beam
ZHOU Yepeng, REN Hongliang, WANG Juan, and CHEN Ling
The axial trapping effect of hollow beam such as LaguerreGaussian beam is better than that of Gaussian beam. The intensity distributions of Gaussian beam and LaguerreGaussian beam were simulated according to their crosssection intensity expression. The trapping Qfactors of Gaussian beam and LaguerreGaussian beam wThe axial trapping effect of hollow beam such as LaguerreGaussian beam is better than that of Gaussian beam. The intensity distributions of Gaussian beam and LaguerreGaussian beam were simulated according to their crosssection intensity expression. The trapping Qfactors of Gaussian beam and LaguerreGaussian beam were calculated in the rayoptics model. The trapping efficiencies of Gaussian beam and LaguerreGaussian beam were compared with different trappped bead size and refractive index, numerical aperture of microscope objective, and the distance from the bottom of the sample cell to the trapped bead. The results show that the maxmium backward trapping Qfactor and trap stiffness of LaguerreGaussian beam are higher than those of the Gaussian beam. LaguerreGaussian beam is more sensitive to spherical aberration due to its special intensity distribution, especially when the numerical aperture of microscope objective is high..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1300 (2013)
Controlled Secure Quantum Dialogue by Using Brown States
YANG Youfeng, YE Zhiqing, and TU Chunlei
A novel scheme of controlled secure quantum dialogue by using Brown states was proposed in this paper. It this scheme, Alice, Bob and Charlie shared a fiveparticle Brown states. Alice made unitary operations on two particles of the Brown states to realize encoding her secret calssical message. Similarly, Bob performedA novel scheme of controlled secure quantum dialogue by using Brown states was proposed in this paper. It this scheme, Alice, Bob and Charlie shared a fiveparticle Brown states. Alice made unitary operations on two particles of the Brown states to realize encoding her secret calssical message. Similarly, Bob performed corresponding unitary transformations to another two particles to encode the information that he wanted to send to Alice. Later, Charlie made Brown base states joint measurement on the Brown final state and announced the measured results. Alice and Bob deduced the opposite party′s information according to Charlie′s announced measurement results and her (his) unitary operation when encoding.They completed quantum dialogue successfully. Then the scheme′s security was discussed and a conclusion was drawn. Compared with the previous quantum dialogues, the secure quantum dialogue scheme adds the controlled party, ensures the communication security, and increases the particles number involving in the communication process and the coding efficiency..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1305 (2013)
Information Leakage Prevention in Quantum Dialogue Using the Measurement Correlation after Entanglement Swapping and Decreasing the Transmission Efficiency
YE Tianyu, and JIANG Lizhen
In order to solve the security threat of information leakage in quantum dialogue protocols, a controlled quantum dialogue protocol without information leakage was proposed, where the controller Alice controlled the bidirectional communication between two communication parties, Bob and Charlie. The problem of informatioIn order to solve the security threat of information leakage in quantum dialogue protocols, a controlled quantum dialogue protocol without information leakage was proposed, where the controller Alice controlled the bidirectional communication between two communication parties, Bob and Charlie. The problem of information leakage was avoided by making full use of the measurement correlation property after entanglement swapping between two maximally entangled GHZ states and decreasing the transmission efficiency. Moreover, the Bellbasis measurement rather than the GHZbasis measurement was needed. Security analysis shows that the active attacks from an outside eavesdropper can be detected, such as the interceptresend attack, the measurementresend attack and the entanglementandmeasurement attack..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1311 (2013)
Influence of Birefringence on Polarization Phase Shifting Interferometry
XUAN Bin
The birefringence of transmission flat/sphere and other components introduces measurement error in Polarization Phase Shifting Interferometry (PPSI). Based on the principle of PPSI, the measurement error was analyzed by using the Jonse maxtrix formulations. It was found that the birefringence generated eight beams inteThe birefringence of transmission flat/sphere and other components introduces measurement error in Polarization Phase Shifting Interferometry (PPSI). Based on the principle of PPSI, the measurement error was analyzed by using the Jonse maxtrix formulations. It was found that the birefringence generated eight beams interference on the CCD, and the measurement error was a function of the ratio of amplitude of test beam and reference beam, the testing cavity phase, the amount and orientation of birefringence. The measurement error varied 2 periods in every fringe. The maximal PV of measurement error would be 4 times of birefringence and the measurement error would be compressed if the orientation of birefringence was consistent. When the birefringence was of the same orientation, the measurement error could be eliminated. A 12 inches material was analyzed. The results show that the birefringence of the 4 inches area in the center was 18 nm, which introduced the measurement error of 72 nm (PV). The birefringence of the material at the edge was 22 nm and the measurement error was 24.9 nm (PV) because of the consistence of birefringence orientation..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1319 (2013)
An Inversion Algorithm of Dynamic Light Scattering Based on Singular Value Decomposition
YU Xiangfei, YANG Hui, YANG Haima, ZHENG Gang, LI Jun, HU Hengqing, and Mark BIGGS
To solve the problem that the traditional inversion of dispersion particle size distribution with the method of dynamic light scattering requires prior knowledge or constraints for the solution, a new inversion algorithm of dynamic light scattering based on singular value decomposition was proposed. Firstly, the HankelTo solve the problem that the traditional inversion of dispersion particle size distribution with the method of dynamic light scattering requires prior knowledge or constraints for the solution, a new inversion algorithm of dynamic light scattering based on singular value decomposition was proposed. Firstly, the Hankel matrix H with the intensity autocorrelation data was constructed. Secondly, the singular value decomposition of H was calculated. Thirdly, the rank of the reconstruction matrix with the singular value of H was determined. Finally, the characteristic value decomposition with the new matrix was calculated, and then the particle size distribution was obtained. The experiment was carried out using two and three different sized particles dispersion respectively. The results show that, in the measuring with two different size particles, the new method can achieve good results without any prior knowledge or constraints for the solution; it is not so good in the measuring with three different size particles and can distinguish three different size particles, but the results have large deviation, especially for the smaller particles. Through the analysis of the experiment, the main reason was found that the small particles scattered light is easily blocked by large particles..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1324 (2013)
Method for Measuring Dispersion of Three Projectiles Impacting Simultaneously
DONG Tao, HUA Dengxin, LI Yan, and NI Jinping
As for the difficulty of measuring the dispersion of three projectiles impacting simultaneously，a method for measuring coordinate by using a single color linear array CCD camera was presented. A highspeed color linear array CCD camera was used, with red, blue and green sectorlike line laser modules as the light sourcAs for the difficulty of measuring the dispersion of three projectiles impacting simultaneously，a method for measuring coordinate by using a single color linear array CCD camera was presented. A highspeed color linear array CCD camera was used, with red, blue and green sectorlike line laser modules as the light source. When passing through the sharing screen of the CCD camera and the light source, the projectiles left projections on the projection board. Meanwhile, the camera captured the images of the projections and projectiles. Then the projection coordinates was identified and calculated by image processing and coordinate computation. By the principle of linear intersection, the impacting coordinates was obtained. The measuring principle and derivation of the measurement formula were described, and the measurement errors were analyzed and simulated. The proposed method, which proves to be effective in measuring the dispersion of three projectiles impacting simultaneously, provides guidance for the development of measuring system for the impacting coordinate of high RF weapons and multibarrel weapons..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1329 (2013)
A New Method for Calibrating Line Structuredlight 3D Measurement Model
LI Guannan, TAN Qingchang, KOU Ying, and ZHANG Yupeng
A machine vision measurement model of line structuredlight was established. Based on the improved camera calibration method, an accurate calibration method of structuredlight plane was proposed. According to the distribution of the structuredlight′s energy along the normal direction of the light′s plane, Gauss fittiA machine vision measurement model of line structuredlight was established. Based on the improved camera calibration method, an accurate calibration method of structuredlight plane was proposed. According to the distribution of the structuredlight′s energy along the normal direction of the light′s plane, Gauss fitting method was used to extract the subpixel coordinates of the light stripe′s center point on the image. In the calibration, the local world coordinate system was established on the surface of the freemoving planar target. Then, the local world coordinates of the stripe′s center point, which were obtained by the parameters of the camera calibration, were translated into the camera coordinate system. Using the obtained calibration points on the light plane, the plane of the structuredlight was estimated in the camera coordinate system. The factors that would affect the precision of the measurement model were fully considered in this method, which could achieve a large number of calibration points. From the measurement of standard gauge block and shaft diameter, this method has high precision in practice..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1334 (2013)
Sensitivity Analysis Method on Detecting Ability of Electrooptical System
TAN Bitao, CHEN Hongbin, WANG Qunshu, and GUAN Xiaowei
Based on analysis of the influence factors on detecting ability of electrooptical system, a theory model of detecting ability on the influence factors is established, concept of sensitive factors of the detecting ability is put forward, an analysis method on weights sensitivity is given, and ration sensitivity researcBased on analysis of the influence factors on detecting ability of electrooptical system, a theory model of detecting ability on the influence factors is established, concept of sensitive factors of the detecting ability is put forward, an analysis method on weights sensitivity is given, and ration sensitivity research of the factors on the detecting ability is realized. Using the ration analysis method, the sensitivity of the electrooptical system is simulated under different initial conditions, and the sensitivity weights of the factors are gained. Results show that the diameter, focus, atmosphere transmittance, detecting SNR threshold, detecting pixel size and the imaging pixel numbers may influence detecting ability obviously, and detecting SNR threshold, detecting pixel size and the imaging pixel numbers change reversely with detecting ability; the sky background brightness, optical transmittance, quantum efficiency and integral time influence the detecting ability secondly, and mainly the sky background brightness change reversely with detecting ability; the ratio of obstruction influences the detecting ability least, changes reversely with detecting ability too; and the weights do not change on different initial conditions. The simulation results prove the completeness and generality of the sensitivity analysis method that can provide technical support for the electrooptical system design..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1340 (2013)
Noise Factors Model of Electron Multiplying CCD and Test Methods
ZHANG Wenwen, QIAN Yuehong, CHEN Qian, and GU Guohua
The noise factor of the electron multiplying CCD was derived based on Poisson distribution model whose theoretical limit was 2, the same as binomial model. The input and output characteristics of the electron multiplying register and the additional noise introduced by signal multiplication process were quantitatively dThe noise factor of the electron multiplying CCD was derived based on Poisson distribution model whose theoretical limit was 2, the same as binomial model. The input and output characteristics of the electron multiplying register and the additional noise introduced by signal multiplication process were quantitatively described. Considering the defects of coating test, the image information of uniform illuminated was analyzed and processed. The influence of readout noise, fixed pattern noise and background values to test results was eliminated. This method reduced the test error and improved the precision. Meanwhile, the chip was uncoated and test process was simplified. Based on theoretical study, the experiments were carried out to test Andor Luca camera. The results show that when the gain is greater than 100, the electron multiplying CCD noise factor is 1.414, consistent with the theoretical values. This demonstrates that the proposed test is feasible and reliable..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1345 (2013)
Water Cooling Technology on High Power LED with the Twisted Tube
WANG Zhibin, ZHANG Jian, LIU Lijun, ZHANG Qian, and LIU Yongcheng
A water cooling structure based on twisted tube to high power light emitted diode (LED) is proposed in this paper, and mechanical model is established. In order to get the best effect of heat dissipation in the case of heat transfer equipment minimization, low flow power consumption etc., the heat transfer performance A water cooling structure based on twisted tube to high power light emitted diode (LED) is proposed in this paper, and mechanical model is established. In order to get the best effect of heat dissipation in the case of heat transfer equipment minimization, low flow power consumption etc., the heat transfer performance of the twisted tube is investigated under different water velocity, wall thickness, length of the twisted section, and the thickness of the twisted tube cavity. In the operating conditions, the structural dimensions of the twisted tube are optimized, and the finite volume method is used to calculate the computation domain. The results of simulation indicate that the twisted tube system after optimizing has better properties of heat transfer; the heat exchanger is used in 180 W high power LED array luminaries, and the temperature of chips is lower than 57.573 9℃; the model and analysis results can provide a significance reference for the engineering radiator design of high power LED lighting system..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1350 (2013)
Circuitry Detection in Printed Circuit Board
QIAO Naosheng, and SUN Ping
In order to carry out printed circuit board (PCB) circuitry detection better, an effective detection method was proposed. Firstly, the basic principle of image preprocessing based on histogram potential function model was analyzed; such principle was applied to PCB photoelectric image preprocessing, and the primary edgIn order to carry out printed circuit board (PCB) circuitry detection better, an effective detection method was proposed. Firstly, the basic principle of image preprocessing based on histogram potential function model was analyzed; such principle was applied to PCB photoelectric image preprocessing, and the primary edge images after removing dark and noise were obtained. Secondly, a line detection method based on improved Hough transform was proposed, the approximate location of line existed in image was ascertained by such method, and the characteristic point sets in the candidate areas were obtained roughly. Then, the basic principle of line detection by using least square method was discussed, the accurate line parameters were acquired by applying least square method to fit these lines detected by the improved Hough transform, and the eventual edge lines were obtained by adding pattern clustering. Finally, the edge detection experiment was carried out by the method in the dark and noisy PCB photoelectric image acquired actually. The results show that the proposed method can better incarnate the PCB circuitry detection..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1355 (2013)
Partial Response Polynomial and Equalizer Design for Signal Waveform Modulation Multilevel Disc
ZHANG Long, NI Guoqiang, PEI Jing, and YANG Bo
The multilevel disc, which uses the signal waveform modulation method for modulation and recording, employs the partial response maximum likelihood detection techniques for the readout channel recovery. With improving the recording density, the complexity and nonlinearity of the optical disc channel modeling will alsoThe multilevel disc, which uses the signal waveform modulation method for modulation and recording, employs the partial response maximum likelihood detection techniques for the readout channel recovery. With improving the recording density, the complexity and nonlinearity of the optical disc channel modeling will also increase. Therefore, a optimized design method of the partial response polynomial and the corresponding equalizer design were introduced to solve it. By finding the critical frequency point between signal frequency band and noisy frequency band in the power spectral density curve of the disc readout signal, the optimized parameters of the partial response polynomial and the partial response equalizer were designed, thus effectively improving the optical readout signal to noise ratio, reducing the error rate of the signal recognition. And this method can also be applied to the partial response maximum likelihood detection system of bluray and other highdensity baseband transmission channel..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1360 (2013)
A Compressive Image Fusion Algorithm Based on Block Sparse Bayesian Learning
LIU Zhe, GU Shuyin, NAN Bingbing, and LI Qiang
Natural signals and images usually have rich temporal structures, which greatly influence the performance of the compressive image fusion algorithms based multiple measurement vectors. In this paper, a new compressive image fusion algorithm was investigated based on block sparse Bayesian learning. The proposed algorithNatural signals and images usually have rich temporal structures, which greatly influence the performance of the compressive image fusion algorithms based multiple measurement vectors. In this paper, a new compressive image fusion algorithm was investigated based on block sparse Bayesian learning. The proposed algorithm used a probabilistic approach, and constructed the temporal structures of images via the positive definite matrices under the multiple measurement vectors model. Thus, the MAP estimate of original images were obtained according to the Bayes rule and the estimation of hyperparameters. To verify the applicability of the proposed method, numerical experiments of image fusion were performed. Numerical results indicate that the proposed method can obviously reduce the sampling number required, and provide better fusion performance for many kinds of images compared to algorithms based on single measurement vector model..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1365 (2013)
Study on the Extraction Method of Radar Life Signal Based on Wavelet Transform
YANG Xiufang, ZHANG Wei, WANG Ruojia, YANG Yuxiang, and YANG dawei
Radar noncontact detection of life signals is severely affected by factors such as environmental noise and the micro movement of detecting object, and the Doppler signal nonstationarity that caused by the interference makes the useful life signalsbreathing and heartbeat signals cannot be extracted with general signalRadar noncontact detection of life signals is severely affected by factors such as environmental noise and the micro movement of detecting object, and the Doppler signal nonstationarity that caused by the interference makes the useful life signalsbreathing and heartbeat signals cannot be extracted with general signal processing method(such as digital filtering, fast Fourier transform). According to this problem, the mathematical model of radar noncontact measuring life information has been established. Using Kband, frequency 24 GHz ,power 30 mW continuous wave radar system has measured a 30 yearsold healthy men. Measurement is carried out in a quiet office environment. There is 2 m distance between radar transmitting head and measure target. Data acquisition card′s sampling frequency is 100 Hz. The data measured are carried out eight scale wavelet decomposition and reconstruction by db3 wavelet basis function. It is success that extracted the person′s breathing and heartbeat signals on the seventh lowfrequency layer and sixth highfrequency layer respectively. Through fast Fourier transform processing of these two layers′ signals, the energy frequency value of the peak area is 0.29 Hz and 1.07 Hz. The frequency difference between the traditional measuring method and the wavelet transform method is 0.04 Hz and 0.03 Hz. The results show that the wavelet transform is used to extract and separate breathing and heartbeat in radar life signals is feasible. It will provide theoretical basis and experimental data for radar noncontact measurement method applied to the clinical monitoring and disaster rescue and so on..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1370 (2013)
Improved LFP Algorithm on Leukocyte Image Texture Feature Extraction and Recognition
PANG Chunying, and LIU Jikui
Leukocyte image feature extraction and classification are studied to improve the correct recognition rate of leukocyte image. For cell texture feature extraction, leukocyte image texture features are extracted by using the improved local fuzzy pattern,and the texture feature extraction method based on local fussy patteLeukocyte image feature extraction and classification are studied to improve the correct recognition rate of leukocyte image. For cell texture feature extraction, leukocyte image texture features are extracted by using the improved local fuzzy pattern,and the texture feature extraction method based on local fussy pattern (LFP) was proposed by making the threshold parameter fuzzy in local binary pattern (LBP). The algorithm introduces in uniform pattern to make the extracted feature dimension decrease to 10 with rotation invariance. The classification of 100 CellAtlas’s white blood cells images was tested with a support vector machine combination classifier established by a directed acyclic graph method. Experimental results show that: the improved local fuzzy pattern algorithm simplifies texture feature quantity to realize “discard the false and retain the true”.The leukocyte image classification and recognition with noise exhibits excellent performance, so that the extracted features have better Robustness. And it has a short running time, high efficiency, leukocyte correct recognition rate is up to 93%. Improved support vector machine classifier shows efficient classification effect,and has better characteristics to small sample analysis..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1375 (2013)
Remote Sensing Image Matching Performance Measurement for Edge Feature
JU Xinuo, SUN Jiyin, WANG Peng, and GAO Jing
In order to improve the effectiveness of reference map production, it is necessary to predict matching performance for early remote sensing images. For edge feature, the saliency and stability of edge determines matching performance. An algorithm for remote sensing image matching performance was proposed based on blockIn order to improve the effectiveness of reference map production, it is necessary to predict matching performance for early remote sensing images. For edge feature, the saliency and stability of edge determines matching performance. An algorithm for remote sensing image matching performance was proposed based on block difference of inverse probabilities and texture cell cooccurrence matrix. Firstly, remote sensing image was divided into potential matching regions and no matching regions based on edge density, and training images were extracted from potential matching regions. Secondly, edge feature vector was computed by block difference of inverse probabilities and texture cell cooccurrence matrix (BDIPTCCM). Thirdly, on basis of the real matching probability computed by simulation experiment, matching probability predicting model was built by support vector regression based on edge feature vector. Lastly, matching probability was predicted for the whole remote sensing image based on the matching probability predicting model. The experimental esult shows that the mean squared error between the predicted matching probability and real matching probability is small and the squared correlation coefficient is high. The model is general for the same satellite images after gray level correction. It can meet the demand of remote sensing image matching performance measure, and provide decision support for selecting matching algorithm..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 11, 1381 (2013)
© Copyright 2018-2021 | Chinese Laser Press. All Rights Reserved 沪ICP备15018463号-20