Journals >Acta Photonica Sinica
Contents
2011
Volume: 40 Issue 10
30 Article(s)
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Research Article
Endoscope Two Dimensional Scanning Fiber Probe and the Driving Method
LI Guang-ping, GAO He, ZHOU Ai, and LIU Zhi-hai
An endoscope scanning fiber probe was designed to perform two-dimensional (2D) scanning for optical coherence tomography based on the PZT. Two piezoelectric ceramic and a thin conductive substrate were used to drive the optical fiber probe. The probe used the cantilever resonance of optical fiber cantilever, imposed thAn endoscope scanning fiber probe was designed to perform two-dimensional (2D) scanning for optical coherence tomography based on the PZT. Two piezoelectric ceramic and a thin conductive substrate were used to drive the optical fiber probe. The probe used the cantilever resonance of optical fiber cantilever, imposed the mixing signals which closed to the resonant frequency of optical fiber on the piezoelectric ceramic, and also stimulated two orthogonal directions vibration of fiber cantilever to achieve two-dimensional scanning. Theoretical model was established and took the finite element simulation analysis was carried out. A practical model was made to carry out experiments and otain the scan pattern. The experimental results realize the optical fiber cantilever two dimensional scanning, and the scanning scope reaches (500×500)μm, adjusting drive signal amplitude can change the scanning range. The theoretical analysis and the simulation was consistent, and verified the feasibility of the scheme..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1447 (2011)
Relative Self-adaptive Filtering Method Applied to Incremental Optoelectric Encoder
MU Yi-ning, LI Ping, YU Lin-tao, ZHANG Guo-yu, and SHEN Chun-ming
The reasons of the high-frequency signals and noise signals generated from the Moire fringe optolectric signal and the relative method of self-adaptive filtering were discussed,in order to improve the quality of Moire fringe optoelectric signals of the incremental optoelectric encoder，decrease the impact of high-order The reasons of the high-frequency signals and noise signals generated from the Moire fringe optolectric signal and the relative method of self-adaptive filtering were discussed,in order to improve the quality of Moire fringe optoelectric signals of the incremental optoelectric encoder，decrease the impact of high-order harmonic frequency in the main count signal and increase the SNR for the stable output of sinusoidal waveform.The window function of the grating pair from both macro and micro perspectives,and the uncertain reasons of the Moire fringe optoelectric signal waveform were analyzed.The original fundamental frequency signal was retained by applying a method of self-adaptive filtering which can filter out high frequency signals.Meanwhile,the adaptive filtering process was derived and proved from the perspective of mathematical model of self-adaptive filtering,and its adaptability was discussed.In order to complete the effectiveness analysis of the self-adaptive filtering,several key indicators and their effects needed to be focused in the design of the self-adaptive filtering encoder.The effect of the adaptive filtering was equivalent to a narrowband band pass filter whose center frequency was the fundamental frequency,and the pass band would change with the random variation of the fundamental frequency.Thus,the relevant self-adaptive filtering could filter out all the high frequency component signals in the count signal except the fundamental frequency signals，and amplify the addition white gaussian noise in the circuit to make the output waveform of the moirefringe optoelectric signal approach the standard sinusoidal wave.The experiment results show that distortion degree of the Moire fringe photoelectric signal is reduced by 8 times..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1452 (2011)
Fluorescence Spectrum of Na2KSb(Cs) Multi-alkali Photocathode of the GenⅡ+ Image Intensifier
LI Xiao-feng, SONG Kai-jun, LIU Ru-biao, and YAN Wen-bo
Fluorescence spectrum of Na2KSb(Cs) multi-alkali photocathode of the GenⅡ+ image intensifier was measured with laser of 785 nm wavelength as the excitation source. It was found that the fluorescence spectrum is not a smooth Gaussian curve, but a Gaussian fluorescence curve superposition of small jagged peaks with a cerFluorescence spectrum of Na2KSb(Cs) multi-alkali photocathode of the GenⅡ+ image intensifier was measured with laser of 785 nm wavelength as the excitation source. It was found that the fluorescence spectrum is not a smooth Gaussian curve, but a Gaussian fluorescence curve superposition of small jagged peaks with a certain frequency interval. Experimental and theoretical analysis show that the small fluorescent jagged peaks on the curve are actually a fringe with relationship of the structure of the GenⅡ+ image intensifier. Pitch between two adjacent interference fringes is proportion to the product of peak wavelength of two adjacent interference fringes, and inversely proportion to the proximity focusing distance of the GenⅡ+ image intensifier. Modulation of interference fringes of fluorescence spectrum is inversely proportion to the thickness of multi-alkali photocathode. By measuring the pitch of two adjacent interference fringes and modulation of Na2KSb(Cs) multi-alkali photocathode of the GenⅡ+image intensifier, the proximity focusing distance and the thickness of Na2KSb(Cs) multi-alkali photocathode of the GenⅡ+ image intensifier can be measured. The results provide an effective means to further increase photocathode sensitivity and resolution of the GenⅡ+ image intensifier..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1459 (2011)
Analysis in Chaotic Characteristics of Electrical-optical Bistable Systems
ZHAO Zhen-hua, ZHANG Sheng-hai, YANG Hua, TAN Jian-feng, and ZHANG Dan
The stability of the electrical-optical bistable system is theoretically analyzed and the stability of the fixed points is researched by diagrammatized mode.Through the method of numerical caculation,the concrete positions of the bifurcation points are caculated,the ways of chaos generation are studied which are intermThe stability of the electrical-optical bistable system is theoretically analyzed and the stability of the fixed points is researched by diagrammatized mode.Through the method of numerical caculation,the concrete positions of the bifurcation points are caculated,the ways of chaos generation are studied which are intermittent chaos and period doubling bifurcations.Bifurcation diagram of the system state evolving with parameter and largest Lyapunov exponent changing with parameter of the system all show that the analysis is reasonable in theory ..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1464 (2011)
Simple Scheme for Preparation of Six-photon Entangled States via Cross-Kerr Medium
ZHU Meng-zheng, and ZHAO Chun-ran
A scheme is presented for preparing maximally entangled states among six modes. The scheme only utilizes weak cross-Kerr nonlinearity and momentum quadrature homodyne measurements on the probe mode of intense coherent light fields. It is relatively easy to generate Dicke states and W states of light fields in the schemA scheme is presented for preparing maximally entangled states among six modes. The scheme only utilizes weak cross-Kerr nonlinearity and momentum quadrature homodyne measurements on the probe mode of intense coherent light fields. It is relatively easy to generate Dicke states and W states of light fields in the scheme. It is not necessary that the cross-Kerr nonlinearity is very large, as long as the coherent light is bright enough. Therefore, this scheme is within the reach of current technology. In addition, only weak coherent light beams, with which single-photon sources have been replaced in the signal modes, are needed in the present scheme since it is difficult to realize single-photon sources in experiments..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1469 (2011)
Phase Modulation Optomechanical Dynamics Induced by Radiation-pressure in Nonlinear Optical Cavity
CHEN Hua-jun, and MI Xian-wu
A cavity optomechanical system containing an optical parametric amplifier is investigated under resolved sideband regime, which enhances the coupling between the movable mirror and the cavity field. The radiation-pressure inducing the movable mirror and the steady-state amplitude of the cavity field displaying an opticA cavity optomechanical system containing an optical parametric amplifier is investigated under resolved sideband regime, which enhances the coupling between the movable mirror and the cavity field. The radiation-pressure inducing the movable mirror and the steady-state amplitude of the cavity field displaying an optical multistable behavior are studied. The modification of mechanical frequency and mechanical damping rate are analyzed induced by radiation pressure, which will change with the change of parametric gain, input laser power and parametric phase. In addition, the fluctuation spectrum of the movable mirror is also analyzed presenting the normal mode splitting with modulating the parametric phase of the driving field. Moreover, an accurate scheme is used to calculate the final effective mean phonon number that demonstrates the ground state cooling. The results show that the cooling of the mirror is dominated by the initial bath temperature, high mechanical quality factor and parametric phase. The parametric phase shows a new way to control the dynamics of nonlinear optomechanical cavity..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1474 (2011)
Numerical and Experimental Analysis on the Operational Reliability of Rotating Mirror for Ultra-high Speed Camera
YU Chun-hui, LI Chun-bo, CHAI Jin-long, JIANG Zhan-hong, LI Jing-zhen, and HUANG Hong-bin
In order to explore a new method of calculating the operational reliability of rotating mirror by numerical analysis and experiment, a mathematic model of operational reliability of rotating mirror was established by the ANASYS parameter design language, based on the Monte Carlo method and the small sample theory. The In order to explore a new method of calculating the operational reliability of rotating mirror by numerical analysis and experiment, a mathematic model of operational reliability of rotating mirror was established by the ANASYS parameter design language, based on the Monte Carlo method and the small sample theory. The result of numerical analysis shows that the value of performance function is further than the value of zero. The correlation coefficient of the maximum stress and the revolving speed of rotating mirror are 0.9, the correlation coefficient of the mirror body density with that is 0.15 and the skewness and kurtosis of the maximum stress, strain and displacement are positive. Meanwhile, the statistical results of the maximum stress, strain and displacement obey normal distribution and show right skewed state. The sample data is concentration appears around the mean value. In the confidence level of 95%, the reliability of rotating mirror is 0.999 9. It can be concluded that the operational reliability of rotating mirror can meet the performance requirement in theory. The maximum stress of rotating mirror is determined by the operational and the density of the mirror body. None of the ten rotating mirror is damaged in the reliability experiment of rotating mirror. The results obtained in the course of this investigation clearly demonstrate that the numerical analysis of operational reliability for rotating mirror is right, which can prove a new method of analyzing the operational reliability with higher practicable and efficient..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1484 (2011)
Temperature Characteristics of Long Period Fiber Gratings Contained High Temperature Resistant Coating Layer
SUN Wei-sheng, SHI Jie-long, CHEN Yuan-yuan, and YANG Qing
Using Point-by-Point method,long period fiber gratings were inscribed in the high temperature resistant fiber by an infrared femtosecond laser.Characteristics of the high temperature resistant fiber was analyzed theoretically.The experiment with long period fiber gratings contained high temperature resistant coating laUsing Point-by-Point method,long period fiber gratings were inscribed in the high temperature resistant fiber by an infrared femtosecond laser.Characteristics of the high temperature resistant fiber was analyzed theoretically.The experiment with long period fiber gratings contained high temperature resistant coating layer indicates that the shift of resonant peak at the temperature range from 20 ℃~300 ℃ keeps a good linearity and the temperature sensitivity is 0.060 5 nm/℃.The coating of the long period fiber gratings is not carbonized due to the existence of the high temperature resistant polyimide materials and grating sensor with good performance.The result shows that the high temperature resistant long period fiber gratings can be used in the high temperature environment for long term application..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1490 (2011)
Spectropolarimetric Bidirectional Reflectance Distribution Modeling for Background Based on LS-SVM Regression
ZHAO Yong-qiang, LIU Dan, CHEN Chao, and CHENG Yong-mei
Relationship between detection geometry and spectropolarimetric bidirectional reflectance distribution function for soil background was analyzed in detail. The modeling of spectropolarimetric bidirectional reflectance distribution function was proposed based on LS-SVM, aiming to extend the value of measured spectropolaRelationship between detection geometry and spectropolarimetric bidirectional reflectance distribution function for soil background was analyzed in detail. The modeling of spectropolarimetric bidirectional reflectance distribution function was proposed based on LS-SVM, aiming to extend the value of measured spectropolarimetric bidirectional reflectance distribution function with limited geometry to whole hemi-sphere space. Results show that the predicted value and experimental value are close and meet the need of correction..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1494 (2011)
Spectrum Resonance Energy Transfer and Energy Analysis of Resorption
GE Li-xin, GAO Shu-mei, and L Si-bin
Synchronous fluorescence spectra of different plasma solution concentrations in the UV wavelength are investigated using three-dimensional synchronous fluorescence spectroscopy. The results show that there are three main excitation peaks of plasma proteins(near 257 nm, 274 nm and 280 nm),and the peak values change withSynchronous fluorescence spectra of different plasma solution concentrations in the UV wavelength are investigated using three-dimensional synchronous fluorescence spectroscopy. The results show that there are three main excitation peaks of plasma proteins(near 257 nm, 274 nm and 280 nm),and the peak values change with different plasma solution concentrations. By changing the offset (that is Δλ) value of the synchronous fluorescence spectra obtained, there are three synchronous fluorescence peaks of plasma, of which the values are 90 nm, 72 nm and 44 nm. According to the experimental data, it shows that the intrinsic fluorescence of the plasma in all groups exists the fluorescence resonance energy transfer and the second light absorption..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1500 (2011)
Formation Process of Pyramids on Single Crystal Si Surface
TIAN Jia-tong, FENG Shi-meng, WANG Kun-xia, Xu Hua-tian, YANG Shu-quan, LIU feng, HUANG Jian-hua, and PEI Jun
The texturing process with alkaline solution added a new additive on single-crystal silicon surface was discussed.At different times,alkaline solution added a new additive was used to etch the Si wafers,and samples were scanned by scanning electron microscopy.The results show that there are a few different size pyramidThe texturing process with alkaline solution added a new additive on single-crystal silicon surface was discussed.At different times,alkaline solution added a new additive was used to etch the Si wafers,and samples were scanned by scanning electron microscopy.The results show that there are a few different size pyramids and smooth regions in large-area on the Si surface after etching 10 min; after etching 15 min,the sizes of pyramids become uniform,and the areas of smooth regions will reduce; after etching 20 min,the etched surface is covered with the 2~4 μm of pyramids,and the distribution is more uniformly-densely; after etching 25 min,the sizes of pyramids increase again in the over-etching process.The experiments illustrate that the new additive can effectively reduce the texturing time,make an ideal textured structure,and be applied in industry..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1505 (2011)
Optical Characterization of Chemical Vapor Deposited Large-grained Polycrystalline Diamond Films by Raman and Infrared Spectroscopy
GU Li-ping, and TANG Chun-jiu
The relation between macro-properties and micro-quantities of the large-grained polycrystalline chemical vapour deposited diamond films was investigated. Considering the growth non-uniformity, the micro-Raman spectra measured on the top growth surface show large variation from spot to spot. Whereas, the micro-Raman speThe relation between macro-properties and micro-quantities of the large-grained polycrystalline chemical vapour deposited diamond films was investigated. Considering the growth non-uniformity, the micro-Raman spectra measured on the top growth surface show large variation from spot to spot. Whereas, the micro-Raman spectra taken on the fine-grained smooth interface of the diamond films show that small deviation and generally can represent the overall quality of the large-grained polycrystaline diamond films, and correlate well with hydrogen content of the film measured by Fourier-transform infrared spectroscopy. It can be concluded that a diamond film with darker color or lower transparency has lower quality and lower phase purity characterized by the larger full width at half maximum (FWHM) and lower intensity of the diamond Raman peak around 1 332 cm－1..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1509 (2011)
Design of Supporting Structure for Plane Grating and Surface Deformation Calculation
LIANG Biao, LIU Wei, and CHEN Cheng
In order to meet the high profile accuracy requirements of plane grating for carbon dioxide detector,the grating and its support structure were designed and analyzed.Firstly,the principles of selecting material for grating sub-assembly and the supporting form for grating were investigated.Then,the calculation method foIn order to meet the high profile accuracy requirements of plane grating for carbon dioxide detector,the grating and its support structure were designed and analyzed.Firstly,the principles of selecting material for grating sub-assembly and the supporting form for grating were investigated.Then,the calculation method for mirror rigid body motion and surface shape error were discussed,based on the Homogenous Coordinate transformation theory and least square method.Subsequently,the surface figure precision and structural strength were analyzed with finite element method subject to thermal-structural coupling loads.A program that can directly call the surface shape error calculation program written by MATLAB was compiled using the secondary development function provide by the finite element analysis software.Simulation results show that the PV≤63 nm,RMS≤12.6 nm.To verify the sub-assembly′s dynamitic character ,the modal and harmonic response analysis were adopted.The results indicate that the fundamental frequencies of the component in three directions are 1 046.3 Hz,1 640 Hz,1 147.5 Hz,respectively.These results demonstrate that the rationality of the supporting structure and can meet the requirements..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1514 (2011)
Athermalization for Mid-wave Infrared Scene Projector Optical System
YANG Le, SUN Qiang, WANG Jian, GUO Bang-hui, LIU Ying, and JIANG Yang
For the requirements of the infrared imaging system performance testing and evaluation applications, an athermalized mid-wave infrared scene projector was designed, based on Digital Micro-mirror Device(DMD). The aberration and design method of the optical system for infrared scene projector were analyzed, and the atherFor the requirements of the infrared imaging system performance testing and evaluation applications, an athermalized mid-wave infrared scene projector was designed, based on Digital Micro-mirror Device(DMD). The aberration and design method of the optical system for infrared scene projector were analyzed, and the athermalization for the scene projector was also discussed. A splitting lens and a compensation lens were used to address the light splitting and aberration balancing problems in the illumination of the telecentric projection systems with a large relative aperture. So the resolution and uniformity were improved, and the field of view was increased. The optical system is composed of a telecentric projection lens and a Kohler illumination lens with tilted image plane. The optical passive athermalization method was introduced into the design, which improved the stability of the system. The spectral band of the system is 3～5 μm , the focal length is 255 mm with a F/2.6 relative aperture, the field of view is 5.1°, and the exit pupil distance is 200 mm. The image quality of the system approaches diffraction limit with MTF>0.6 at spatial frequency 17 lp/mm in the whole operating temperature range of －20 ℃~ 60 ℃. The proposed athermalized mial-wave infrared scene projector has the advantages of high resolution, excellent uniformity, compact size and low weight..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1521 (2011)
Linearity Analysis on Bellows Actuator of a Fine Objective Lens
YUAN Wen-quan, GONG Yan, ZHANG Wei, WANG Xue-liang, NI Ming-yang, and ZHAO Lei
Geometrical nonlinearity of a fine objective lens′ bellows actuator was analyzed with finite element method, and characteristics of bellows actuator were evaluated by linearity. Geometric nonlinear deformations of some common bellows(U shape, S shape, C shape, rectangle shape and triangle shape) were analyzed via the fGeometrical nonlinearity of a fine objective lens′ bellows actuator was analyzed with finite element method, and characteristics of bellows actuator were evaluated by linearity. Geometric nonlinear deformations of some common bellows(U shape, S shape, C shape, rectangle shape and triangle shape) were analyzed via the finite element method, the stoke and linearity of these actuators were obtain with the least square method. The results show that: the S shaped bellows, of which linearity is up to 0.161%, is the best one for large stoke bellows actuator, and the triangle shaped bellows, of which linearity is up to 0.135%, is the best one for small stoke bellows actuator..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1526 (2011)
Synchronous Carrier Extracting Method Based Demodulation Scheme for Fiber Optic Sensor Using Phase Generated Carrier
ZHANG Yi, JIA Bo, XU Hai-yan, WU Hong-yan, and XIAO Qian
A Michelson interferometer based fiber optic sensor was constructed with the application of a 3×3 coupler, faraday rotator, and other optical elements. Phase generated carrier method was applied to modulate the laser. The constructed fiber disturbance sensor was used to a long-distance field safety monitoring. AccA Michelson interferometer based fiber optic sensor was constructed with the application of a 3×3 coupler, faraday rotator, and other optical elements. Phase generated carrier method was applied to modulate the laser. The constructed fiber disturbance sensor was used to a long-distance field safety monitoring. According to the analysis of the interferometer system output, a signal component with the same frequency of the carrier was found in the output signal. Consequently, the carrier signal could be extracted synchronously with a narrow-band band pass filter with center frequency being set to the carrier frequency. When the extracted carrier signal was used to passive homodyne demodulation procedure of phase generated carrier method, the external disturbance signal could be acquired. The method of synchronous carrier extraction was introduced, the feasibility of this method was obtained through theoretical derivation, and the correctness of this theory was authenticated through software simulation and experiment. The low frequency influence to the extracted carrier was also discussed, and the solution was given for the limit of the influence cased by the low frequency signal. This method can be applied especially in the condition when modulation is set far from the output signal to make it hard to acquire the carrier signal..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1531 (2011)
Modeling of Optical Circuit and Analysis of Polarization Errors for the Reflective Optical Voltage Sensor
LI Yan, ZHANG Min, FENG Xiu-juan, LI Li-jing, LI Chuan-sheng, and YANG Ming
The polarization errors of optical circuit limit the accuracy of the quasi-reciprocal reflective optical voltage sensor. The transmission models of discrete optical components and the splice points were developed based on the theory of Jones matrix. Also, a comprehensive transmission model of optical system was derivedThe polarization errors of optical circuit limit the accuracy of the quasi-reciprocal reflective optical voltage sensor. The transmission models of discrete optical components and the splice points were developed based on the theory of Jones matrix. Also, a comprehensive transmission model of optical system was derived. The influences of polarization errors on the system performance were analyzed and simulated theoretically. The theoretical and experimental results show that the sensitivity is dependent on factors including the degree of polarization of the light source, the extinction ratio of the polarizer and the azimuth angle between the principle axes of the polarizer and the modulator, the polarization errors induced by which exhibit no influences on the accuracy when the gain of the electrical circuit is large enough. The polarization errors induced by the rotation angle of Faraday rotator, the azimuth angle of the collimator-Faraday rotator with respect to the BGO crystal can mainly result in measurement error, which is sensitive to the environmental changes and brings on the output drift. According to the standard of IEC 60044-7 0.2S, the rotation angle of Faraday rotator and the azimuth angle between collimator-Faraday rotator and BGO crystal should be less than 1.6° and 1.85°, respectively .It is also useful to the design of the optical circuit and the errors compensation of the quasi-reciprocal reflective optical voltage sensor..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1536 (2011)
An Improved Algorithm for 3D Reconstruction Based on Color CGHs of 3D Objects Using Multiple Projection View Images
XUE Dong-xu, YANG Yong, ZHANG Hui-min, ZHAO Xing, and YUAN Xiao-cong
A novel method for the acquisition of full-color three dimensional (3-D) images of real objects was proposed based on multiple projections. In order to improve sampling efficiency, an orthogonal scanning mode was presented, instead of conventional 2-D scanning mode, to capture a series of projection images by a color cA novel method for the acquisition of full-color three dimensional (3-D) images of real objects was proposed based on multiple projections. In order to improve sampling efficiency, an orthogonal scanning mode was presented, instead of conventional 2-D scanning mode, to capture a series of projection images by a color charge coupled device in both vertically and horizontally direction with an incoherent light source. The 3-D Fourier spectra were extracted by using the projection images. The computer-generated hologram (CGH) was synthesized and the numerical 3-D image was reconstructed. The experimental results show that the acquisition method of multiple projection view images has good performance, high efficiency. Moreover, a new extraction method was adopted to improve viewing quality of 3-D imaging by using the multi-circle sampling area. Comparison with experimental result shows that more available data is used to synthesize the CGH and a significant improvement in image definition..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1542 (2011)
Video Quality Assessment Based on Gradient and Motion Estimation
Liu Wenjuan, Li Sumei, Zang Yanjun, and Wei Jinjin
Digital video quality assessment plays an important role in video compression , processing and video communications. A method of video quality assessment based on gradient and motion estimation was proposed according to the existing evaluations and human visual system. The new method takes into account the characteristDigital video quality assessment plays an important role in video compression , processing and video communications. A method of video quality assessment based on gradient and motion estimation was proposed according to the existing evaluations and human visual system. The new method takes into account the characteristics of the edge information, the temporal correlation between frames, and effects of the scenes′ contents changes on the quality of the video. The experiments results show that it is coherent to the human eye's visual effects on the distortion video based on H.264..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1547 (2011)
Multi-scale Unsupervised Color Image Segmentation
CHEN Zhi-gang, CHEN Ai-hua, CUI Yue-li, and XIANG Mei-jing
Nonsubsampled contourlet transform is a new multi-scale multi-resolution powerful analysis tool. An unsupervised segmentation algorithm for color image is proposed based on nonsubsampled contourlet transform. Firstly, for nonsubsampled contourlet transform shift invariance, multi-scale edge is extracted in transform doNonsubsampled contourlet transform is a new multi-scale multi-resolution powerful analysis tool. An unsupervised segmentation algorithm for color image is proposed based on nonsubsampled contourlet transform. Firstly, for nonsubsampled contourlet transform shift invariance, multi-scale edge is extracted in transform domain by using gradient vector method. Then, local low-frequency energy texture features and high-frequency multi-scale Zernike moments texture features are extracted from low-frequency sub-band and high-frequency sub-band in transform domain and fusing them. Finally, detecting seed points in edge map to represent color image regions, the region growing followed by region merging method is applied for segmentation by color and texture Euclidean distance. The experimental results show that the algorithm can automatically fulfill unsupervised segmentation for color image by combining color, multi-scale edge and texture properly, and has more precise and more robust segmentation effect than traditional algorithm..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1553 (2011)
A Weighted Hausdorff Distance Algorithm Based on Multi-scale Edge Measure Fusion
QU Sheng-jie, PAN Quan, CHENG Yong-mei, ZHAO Chun-hui, and LING Zhi-gang
The general edge weighted Hausdorff distance has limited effects on improving the noise robustness, because single-scale edge detection operator itself is sensitive to noise which lesds to little difference between the real and false edge. A novel weighted Hausdorff distance algorithm was proposed based on multi-scale The general edge weighted Hausdorff distance has limited effects on improving the noise robustness, because single-scale edge detection operator itself is sensitive to noise which lesds to little difference between the real and false edge. A novel weighted Hausdorff distance algorithm was proposed based on multi-scale edge measure fusion (EFWHD). Multi-scale edge measure was extracted and then evidence theory was brought in. The basic belief assignment of multi-scale edge measure was constructed by a new method of bidirectional exponent and then fused by Conflict-Redistribution DSmT. To distinguish the real edge and high-frequency noise furtherly, the general weighted hausdorff distance formula was modified and the new formula was proposed which can use the fused edge measure more effectively. Simulation with both optical and SAR images shows that the edge detection method of this paper suppresses noise effectively, meanwhile preserving rich details and the contrast tests are processed to verify the efficiency of improving noise robustness..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1560 (2011)
Phase Retrieval Based on Transport-of-intensity Equation
CHENG Hong, ZHANG Quan-bi, WEI Sui, and SHEN Chuan
Phase retrieval based on the transport-of-intensity equation is researched to calculate phase information from the intensity measurement. A practical phase retrieval system is designed including classic Fourier phase retrieval algorithm and phase retrieval algorithm based on the total variation. Only measurements of thPhase retrieval based on the transport-of-intensity equation is researched to calculate phase information from the intensity measurement. A practical phase retrieval system is designed including classic Fourier phase retrieval algorithm and phase retrieval algorithm based on the total variation. Only measurements of the spatial intensity of the optical wave in focal plane and defocus plane around are needed to retrieval the phase by solving a second-order differential equation. Phase retrieval based on the transport-of-intensity equation overcomes the disadvantages of iteration uncertainty and slow convergence compared with the iterative phase retrieval technique. The experimental results show that the phase retrieval based on the transport-of-intensity equation is able to quickly and effectively calculate phase information from the intensity measurement, and information in edge is remained at the same time of phase retrieval based on the total variation compared to Fourier algorithm..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1566 (2011)
Three-dimension Reconstruction Technique of Concrete CT Images Based on Modified Ray-casting
ZHAO Liang, LI Chang-hua, CHEN Deng-feng, DANG Fa-ning, and WANG Li-li
The study of concrete based on CT Images has been a heated issue in recent years. Normally the study focuses on 2-D meso--concrete image, but sutdy on the construction of 3-D meso-concrete are not paid much attention to which limits the scope of the research and intervene with the overall analysis of calculation on theThe study of concrete based on CT Images has been a heated issue in recent years. Normally the study focuses on 2-D meso--concrete image, but sutdy on the construction of 3-D meso-concrete are not paid much attention to which limits the scope of the research and intervene with the overall analysis of calculation on the forces in any circumstances. Owing to this point, The author offers a new tech-VTK system based on the ray-casting which also can achieve visualization. After tests, the new method is obviously more accurate and effective in guidance to build concrete material numerical model. In short, it is instructive and significant to solve the problems in this field..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1571 (2011)
A Blind Robust Quantization-based Watermarking Algorithm Against Brightness-and-contrast Adjustment
YE Tian-yu
Lots of existing image watermarking algorithm cannot resist brightness-and-contrast adjustment.In order to solve the problem,a blind robust quantization-based watermarking algorithm against brightness-and-contrast adjustment is proposed.An original image is transformed with discreet wavelet transform,and its low frequeLots of existing image watermarking algorithm cannot resist brightness-and-contrast adjustment.In order to solve the problem,a blind robust quantization-based watermarking algorithm against brightness-and-contrast adjustment is proposed.An original image is transformed with discreet wavelet transform,and its low frequency band is split into non-overlapping blocks.Then,each block is conducted with discreet cosine transform.Finally,a watermark is inserted into low frequency coefficient from each block after discreet cosine transform through odd-even quantization.At the detection end,revision for resistance against brightness-and-contrast adjustment is imposed on the attacked watermarked image at first,and then a watermark is blindly extracted through odd-even judgment.Experimental results show that it has strong robustness towards brightness-and-contrast adjustment,and adding gaussian noise,adding salt&pepper noise,cropping,median filter,gaussian low-pass filter and JPEG compression..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1577 (2011)
Sound Fields Generated by Laser-induced Liquid Breakdown
GAO Li-min, and CAO Hui
The sound field excited by laser-induced liquid breakdown is studied using fundamental theories of acoustics.Based on plasma ellipsoid model，a plasma elliptical disk model is proposed to simplify the processing and theoretical calculations.Via putting forward the plasma elliptical dish model,the law of sound pressure aThe sound field excited by laser-induced liquid breakdown is studied using fundamental theories of acoustics.Based on plasma ellipsoid model，a plasma elliptical disk model is proposed to simplify the processing and theoretical calculations.Via putting forward the plasma elliptical dish model,the law of sound pressure and a plasma elliptical dish vibration analytical expression of displacement are obtained,which provide certain theoretical basis to optical breakdown in liquid..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1586 (2011)
A Simulated Model for Analyzing Backscattering of Laser Pulse Propagating in Water Based on Fournier Forand Volume Scattering Function
HAN Biao, LIU Ji-fang, ZHOU Shao-jie, SUN Yan-ling, LIU Kun-lun, and WANG Xu
Based on Fournier Forand volume scattering function, a simulated model was built to analyze the backscattering properties of laser pulse propagating in water. In this model, in order to obtain light′s impulse response of backscattering in water, Monte Carlo method was used to simulate the process of photon′s propagatinBased on Fournier Forand volume scattering function, a simulated model was built to analyze the backscattering properties of laser pulse propagating in water. In this model, in order to obtain light′s impulse response of backscattering in water, Monte Carlo method was used to simulate the process of photon′s propagating. Then, the initial laser pulse and the impulse response were convolved, and the convolution result Fourier spectral was calculated to get the time- and frequency-domain characteristic of the laser pulse′s backscattering signal. Using this model, the influence of the size distribution of scatterer, the relative refractive index of scatterer to water and the attenuation coefficient on the backscattering properties of laser pulse propagating in water was analyzed when the initial laser pulse was approximated by Gaussian function. The result shows that, with the increase of the relative amount of small scatterer, the relative refractive index of scatterer to water and the attenuation coefficient, the energy of the backscattering signal is enhanced, the width is broadened , and the low frequency component is increased notablely..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1590 (2011)
Wavelength Sensing Based on the Goos-Hnchen Effect
XIAO Ping-pinga, QI Minb, and HU Hong-wua
The Goos-Hnchen effect,which is enhanced by the resonance of the guided mode in a symmetrical metal-cladding waveguide with submillimeter scale,is used to detect the slight variation of wavelength.The symmetrical metal-cladding waveguide consists of a guiding layer and two metal-cladding layers.When the laser beam incThe Goos-Hnchen effect,which is enhanced by the resonance of the guided mode in a symmetrical metal-cladding waveguide with submillimeter scale,is used to detect the slight variation of wavelength.The symmetrical metal-cladding waveguide consists of a guiding layer and two metal-cladding layers.When the laser beam incidents on the surface of the coupling prism with a small incident angle,the ultrahigh-order mode will be excited under the phase-matching condition,which exhibits a strong dispersion ability of the wavelength.Theoretical analysis indicates that the GH lateral shift is closely related to the intrinsic and radiative dampings of the waveguide.As the two dampings of SMCW approach to the best matching condition,the GH shift will exhibit a great enhancement and the lateral GH shift may reach several hundreds of microns.Since the detecting signal is proportional to the displacement of the light beam,the measurement will not be affected by the fluctuation of the light intensity.A wavelength resolution of 0.2 pm near the wavelength of 859 nm is demonstrated in experiment..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1595 (2011)
Design of Light Pipe with Microstructures for Touch Screen
WEI Xiao-na, BO Yang, LIU Peng-fei, and LU Kan
Taking the laser diode as the light source, the traditional inner structure of touch screen is improved using a light pipe with microstructures. The single row of LED is replaced by a combination of the laser and the light pipe. Light pipe uses PMMA as the material, of which the refractive index n2=1.49. In the total rTaking the laser diode as the light source, the traditional inner structure of touch screen is improved using a light pipe with microstructures. The single row of LED is replaced by a combination of the laser and the light pipe. Light pipe uses PMMA as the material, of which the refractive index n2=1.49. In the total reflection conditions, the geometric parameters of the light pipe′s micro-structure can be solved by a certain equation. The optical and mechanical models of the light pipe are established respectively, and the results show that this proposed design method achieve high resolution ratio and large size of the touch screen..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1599 (2011)
Analysis of Polarization-independent Optical Directional Coupler Based on Slot Waveguides for Long-wave Infrared
LI Guo-yi, WEI Yu-xin, ZHOU Qiang, YANG Jian-yi, WANG Ming-hua, and JIANG Xiao-Qing
The research of long-wave infrared silicon waveguided components is triggered by the development of integrated optic devices.The validity of Scale-up principle for designing the size of slot waveguides in this waveband is demonstrated, the characteristics such as contain factor and polarization were explained.The polarThe research of long-wave infrared silicon waveguided components is triggered by the development of integrated optic devices.The validity of Scale-up principle for designing the size of slot waveguides in this waveband is demonstrated, the characteristics such as contain factor and polarization were explained.The polarization-independent optical directional coupler based on slot waveguides was attained at the wavelength of 10.6μm..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 10, 1603 (2011)
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