Journals >Opto-Electronic Engineering
Contents
2014
Volume: 41 Issue 1
17 Article(s)
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Research Article
Two Motors Synchronization Control for Photoelectric Theodolite
TANG Tao, ZHANG Tong, DU Junfeng, HUANG Yongmei, FU Chengyu, REN Ge, and ZHANG Mengwei
It is very important to use two motors synchronization control in photoelectric theodolite tracking control system. First, the direct drive function of two motors is modeled. Compared with single motor direct control system, the resonance frequency of two motors control systems is the same, while the anti-resonance freIt is very important to use two motors synchronization control in photoelectric theodolite tracking control system. First, the direct drive function of two motors is modeled. Compared with single motor direct control system, the resonance frequency of two motors control systems is the same, while the anti-resonance frequency of two motor control system is 1.414 times than those of sing motor system. Because of hard coupling for direct drive, the speed of two motor of the system is the same, and the synchronization of torque for motors is critical. The current master-slave control technique is effective to synchronize the torque, in which the current loop of the master motors is tracked by the other slave motor. The speed feedback into the input of current loop of the master motors. The experiments test the performance of the two motors drive system. The random tracking error is 0.011 9″for the line trajectory of 0.01°/s..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 1, 1 (2014)
The Research of Two-dimensional Precision Adjustment Mechanism for Focal Plane
CHAI Fangmao, FAN Yanchao, XIN Hongwei, YANG Huisheng, BAO He, and LI Zhilai
According to the requirements of adjusting focus and drift angle for the large diameter, long focal length and high resolution space optical remote sensor, a two-dimensional precision adjustment mechanism is proposed for focal plane based on the high rigidity, strength ball spline structure and the high precision ball According to the requirements of adjusting focus and drift angle for the large diameter, long focal length and high resolution space optical remote sensor, a two-dimensional precision adjustment mechanism is proposed for focal plane based on the high rigidity, strength ball spline structure and the high precision ball screw structure, which is able to realize the purpose of adjusting the focus and drift angle. This two-dimensional precision adjustment mechanism for focal plane not only has the advantage of compact structure, taking up small space and light quality, but also has enough strength and stiffness and excellent self-locking and resistance to cold welding properties. The quality of this structure is 5.5 kg. Its focusing range and resolution are ±2 mm and 0.17 μm, respectively. The adjustable range for drift angle is ±5, while resolution is better than 0.000 2″. The test result shows that all the parameters meet the requirements. So it’s suitable for application on the large diameter, long focal length and high resolution space optical remote sensor..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 1, 6 (2014)
Raman-based Fiber-optic Distributed Temperature Sensor with Laser Pulse
CHEN Zhibiao, WEI Deke, and JIANG Mingwu
A long sensing fiber was divided into 2 segments. An optical splitter was used to split a laser pulse into 2 channels which were connected with front and rear sensing fiber, respectively. Laser pulse was injected into the 10.7 km sensing fiber by a wavelength division multiplexer after transmitted through another 12.5 A long sensing fiber was divided into 2 segments. An optical splitter was used to split a laser pulse into 2 channels which were connected with front and rear sensing fiber, respectively. Laser pulse was injected into the 10.7 km sensing fiber by a wavelength division multiplexer after transmitted through another 12.5 km dedicated fiber instead of the front 12 km sensing fiber. This method can effectively improve Raman signal intensity of the rear segment sensing fiber. 22.7 km sensing length was achieved with temperature measurement accuracy of ± 0.5 ℃ for both of the front and rear segment of the sensing fiber..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 1, 12 (2014)
The Vibration Signal Recognition of Optical Fiber Perimeter Based on Time-frequency Features
ZHU Chenghui, QU Yongzhong, and WANG Jianping
In the optical fiber perimeter security system, both deliberate invasion and environmental noise can cause optical fiber sensor vibration. It is very important to distinguish the invasion and no invasion events under ensuring the high sensitivity of system. In order to identify the various fiber optic vibration signalsIn the optical fiber perimeter security system, both deliberate invasion and environmental noise can cause optical fiber sensor vibration. It is very important to distinguish the invasion and no invasion events under ensuring the high sensitivity of system. In order to identify the various fiber optic vibration signals effectively, we propose two-stage discriminative method based on the invasion and environmental noise vibration signals short features on time-domain as well as scale energy distribution on complex wavelet domain to recognize the fiber optic signal. The first level use the time-domain characteristics of short-time energy and short-time zero crossing rate to judge whether there is a vibration happening. The second level use complex wavelet extraction the energy distribution features, combining with the time domain characteristics form the characteristic vector, Support Vector Machine (SVM) as the classifier to identify whether it is a intrusion signal and intrusion type. The experiment results show that this method can identify the intrusion signals and environment noise signals effectively, improve the system alarm rate and reduce the nuisance alarm rate..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 1, 16 (2014)
Calibration and Error Analysis of Strain Coefficient of Optical Fiber Based on Stretching Device
YAN Jisong, YUAN Ming, ZHANG Zhihui, and WANG Dongsheng
In the distributed optical fiber sensor system, due to the difference of the manufacturer, materials, doping and the production process etc., the basic parameters of optical fiber sensor such as the refractive index, strain and temperature coefficient are slightly different, and it must be calibrated for sensing fiber In the distributed optical fiber sensor system, due to the difference of the manufacturer, materials, doping and the production process etc., the basic parameters of optical fiber sensor such as the refractive index, strain and temperature coefficient are slightly different, and it must be calibrated for sensing fiber before application. A method for calibrating the strain coefficient of optical fiber based on Brillouin Optical Time Domain Reflectometer (BOTDR) and stretching device was proposed, then the error analysis was presented. Several calibration experiments were conducted on G.652 single mode fiber with different initial length, and the strain coefficients calibrated were 0.050 2 ~ 0.051 2 (MHz/με), which showed good repeatability. Verified by BOTDR, the measured strain values agreed well with the results of theoretical calculation. The experimental results show that the calibration method is practical, easy to be implemented. It can be used both for the calibration of optical fiber sensing system and for the strain calibration of BOTDR in the production process..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 1, 23 (2014)
A Fast Signal Processing Method Based on Simplex Code in BOTDR System
LI Da, ZHANG Yanjun, and FU Xinghu
A new method which combines the Simplex code with the average superposition algorithm—S superposition algorithm is proposed. In the condition of the same denoising effect of the two methods, S superposition algorithm can substantially reduce the number of superposition to reduce the time of the signal processing and soA new method which combines the Simplex code with the average superposition algorithm—S superposition algorithm is proposed. In the condition of the same denoising effect of the two methods, S superposition algorithm can substantially reduce the number of superposition to reduce the time of the signal processing and solve the problem broughtby the length of Simplex code. In order to verify the correctness of the S superposition algorithm, create mathematical model of the distributed optical fiber sensing system. Simulation experiment is launched with the mathematical model. The results of the simulation experiment show that the S superposition algorithm can greatly reduce the signal processing time. It proves the correctness and validity of the new method..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 1, 29 (2014)
The Multi Target Recognition of Intrusion Signal of Perimeter Security with Distributed Fiber-optic Sensor
YU Xiaomang, LUO Guangming, ZHU Zhenmin, and YE Jian
The signal source that may be found in perimeter security system of distributed Fiber-optic includes noise signals caused by different environmental state and intrusion signals caused by common kinds of invasion. In order to distinguish noise signals from intrusion signals, a new method based on the M-Z interferometersThe signal source that may be found in perimeter security system of distributed Fiber-optic includes noise signals caused by different environmental state and intrusion signals caused by common kinds of invasion. In order to distinguish noise signals from intrusion signals, a new method based on the M-Z interferometers is proposed. In addition, by using BP neural network, we can recognize different targets while a variety of invasive signals through the Fiber-optic without any ambient noises. Experiment results show that the proposed method is able to differentiate intrusion signals from ambient noises effectively. What’s more, the recognition rate of the system is improved while the false alarm rate is reduced..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 1, 36 (2014)
The Ripple Noise in the Phase Modulation and Demodulation System of Optical Micro-cavities
ZHANG Jianhui, AN Panlong, XU Pengfei, ZHENG Yongqiu, XUE Chenyang, ZHANG Wendong, and YAN Shubin
The ripple noise comes from the FP resonator structure formed in the joint between discrete optics according to the theoretical analysis for the presence of it in the modulation and demodulation system. According to the analysis of the fiber FP cavity characteristics, transmittance function of the FP cavity is obtainedThe ripple noise comes from the FP resonator structure formed in the joint between discrete optics according to the theoretical analysis for the presence of it in the modulation and demodulation system. According to the analysis of the fiber FP cavity characteristics, transmittance function of the FP cavity is obtained. Its resonance characteristics were simulated and the resonance characteristic curves were obtained under different facets with different reflectivity. The relationship between the reflectivity and the finesse, and the influence of the reflectivity on the characteristics of the resonant are obtained. The two methods to suppress the ripple noise are proposed, the facet reflection method and the phase modulation suppression method. The result of the experiment shows that both methods suppress the ripple noise in the system effectively, improve the signal-to-noise ratio of the resonant signal, and lay the foundation to obtain the demodulated signal and track the optical micro-cavity resonance point..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 1, 42 (2014)
Fast Hologram Generation for Active Holographic Display
CHEN Huirong, FU Shenghao, and WANG Yuanqing
In holographic three-dimensional display, the generation speed of the hologram affected its practical application. Particularly, it is difficult to generate hologram of the large size and large scene fast. In order to solve the problem, the pupil tracking and directional backlight were applied to holographic display. TIn holographic three-dimensional display, the generation speed of the hologram affected its practical application. Particularly, it is difficult to generate hologram of the large size and large scene fast. In order to solve the problem, the pupil tracking and directional backlight were applied to holographic display. The formation of active holographic display is a way to solve the dynamic holographic display problem. For the need of active holographic display, a parallel hologram generation scheme based on two-step hologram algorithm and spatial redundancy lightwave removal algorithm was proposed. Firstly, rank contribution components were calculated by the two-step algorithm. Secondly, the scope of the sub-hologram was determined by the spatial redundancy lightwave removal algorithm. Finally, a reasonable CUDA parallel computing program was designed to generate hologram of the large size and large scene fast. The experimental results indicated that the algorithm was effective and feasible. With the two-step algorithm, the computing speed was accelerated about ten times on the basis of parallel computing technology. The contradiction between the large scene and spatial sampling interval was also overcome effectively by the spatial redundancy lightwave removal algorithm..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 1, 48 (2014)
Multiple Binary Images Optical Encryption Technology Based on JTC and Spread Spectrum Technology
WANG Zhipeng, MA Maofen, and QIN Yi
In order to improve the efficiency of transmission and security of the optical encryption system, a multiple binary images optical encryption technology is proposed. This technology uses digital method and optical method in the encryption process, and pure optical method in the decryption process. In the encryption proIn order to improve the efficiency of transmission and security of the optical encryption system, a multiple binary images optical encryption technology is proposed. This technology uses digital method and optical method in the encryption process, and pure optical method in the decryption process. In the encryption process, each original image’s spectrum is spread by multiplying with a encryption key and then all the images are added together to generate a composite image. The composite image is put on the input plane of the joint transform correlator for optical encryption. In the decryption process, each of the original images needs to be extracted from the composite image by an aperture in the frequency domain. Through theoretical analysis and computer simulation, the multiple binary images optical encryption technology system is very simple, and it has high image multiplexing capacity and security..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 1, 54 (2014)
The Improved DRLSE Ultrasound Image Segmentation Model Based on Phase Congruency
ZHENG Wei, PAN Zhengyong, and HAO Dongmei
As the Distance Regularized Level Set Evolution (DRLSE) model is difficult to deal with weak boundary images and has inefficient curve evolution, a novel ultrasound image segmentation model based on the phase information in a variational level set formulation is proposed. The proposed model constructs a new boundary inAs the Distance Regularized Level Set Evolution (DRLSE) model is difficult to deal with weak boundary images and has inefficient curve evolution, a novel ultrasound image segmentation model based on the phase information in a variational level set formulation is proposed. The proposed model constructs a new boundary indicator function by using the theory of phase congruency detection, instead of the boundary stopping function in the model of DRLSE, and then come to the new energy functional. Experimental results show that the method accelerates the evolution speed. Furthermore, it can extract thyroid tumors ideally in the segmentation of ultrasound images..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 1, 60 (2014)
Multimodality 3D Medical Image Registration in Clifford Algebra Space
HUA Liang, HUANG Yu, DING Lijun1, FENG Hao, and GU Juping
3D/3D medical image registration has important clinical significances and medical value, especially to the operation navigation and lesion location in brain surgery, the different modal 3D image data of patients need to be registered so that the medical characteristics of target tissue can be analyzed more completely a3D/3D medical image registration has important clinical significances and medical value, especially to the operation navigation and lesion location in brain surgery, the different modal 3D image data of patients need to be registered so that the medical characteristics of target tissue can be analyzed more completely and accurately. On the basis that classical registration methods are researched, the classical registration methods are embedded in Clifford algebra space, and the Geometric elements during registration calculating and the translation operator Geometric rotation operator during registration operation are built in Clifford algebra space. Then the floating image is operated with corresponding operator to achieve multimodality 3D medical image registration in head and skull. This registration method is applied to two famous 3D medical data base in the world. The experimental result indicates that this method not only inherits the advantage of classical registration methods, but also has high registration precision and intuitive geometric meaning, reducing the computing time..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 1, 65 (2014)
Calibration for Wavelength Linearity of Grating Spectrometer
WANG Shaoshui, ZHU Xingbang, SUN Quanshe, and ZHAO Facai
The spectrum power of low-pressure mercury is weak, and the spectral lines cannot be traceable to national standard. Using SHG and FHG technique, the laser at 532nm and 266nm was obtained based on 1064nm single solid-state ring laser. Using modulation transfer spectroscopy, the frequency of the 532nm laser was stabilizThe spectrum power of low-pressure mercury is weak, and the spectral lines cannot be traceable to national standard. Using SHG and FHG technique, the laser at 532nm and 266nm was obtained based on 1064nm single solid-state ring laser. Using modulation transfer spectroscopy, the frequency of the 532nm laser was stabilized at 10 hyperfine Spectra of 127I R (56)32-0. The wavelength accuracy of grating spectrograph was calibrated. The experiment results prove that the wavelengths of frequency stabilized wavelength source have strict multiple relationship, and the wavelength accuracy of grating spectrograph can be calibrated accurately and effectively. So this technique has good application value..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 1, 73 (2014)
Salient Object Detection Based on Image Contrast
ZOU Qiang, JIANG Ping, ZHOU Jin, and LU Zeqiong
In order to detect all kinds of salient object in natural scene, we present a method which combined image global contrast and local contrast information. Firstly, use global and local contrast detector to get the global and local contrast saliency map. Then, make border cut and morphological dilation on local contrast In order to detect all kinds of salient object in natural scene, we present a method which combined image global contrast and local contrast information. Firstly, use global and local contrast detector to get the global and local contrast saliency map. Then, make border cut and morphological dilation on local contrast saliency map. Finally, combine global and local contrast saliency map and make center bias to get final saliency map. We provide quantitative evaluation which shows the proposed method outperforms many other state-of-art methods..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 1, 77 (2014)
Lock-in Imaging Based on Modulated White Light
JIANG Bo, YU Xuecai, WAN Congling, and LI Zesi
Laser lock-in imaging technology is a method for obtaining target image from very powerful background lights based on the combination of phase discrimination of weak signal detection with the optical, which is applied in industrial measurement. A lock-in imaging based on modulated white LED is put forward based on the Laser lock-in imaging technology is a method for obtaining target image from very powerful background lights based on the combination of phase discrimination of weak signal detection with the optical, which is applied in industrial measurement. A lock-in imaging based on modulated white LED is put forward based on the phase technology of laser lock-in imaging. The white LED controlled by voltage modulation is used to illuminate interested target area where there are strong lights, and a color CCD image sensor is employed to take image synchronically. Then we adopt phase discrimination to handle the component of image’s RGB respectively. The experimental results show that lock-in image based on white LED is capable of getting image clearly from very powerful background light, and expands the range of application. The video monitoring, industrial measurements and other fields will have broad application and practical value..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 1, 83 (2014)
HEVC-oriented Depth Video Preprocessing
TIAN Zhaixing, PENG Zongju, JIANG Gangyi, YU Mei, CHEN Fen, and SHAO Feng
The depth video obtained by depth camera or depth estimation software is inaccurate, which will affect the compression performance. So, a HEVC-oriented depth video preprocessing algorithm is proposed. Firstly, the edge-mask of depth video is abstracted. Secondly, the depth pixels are classified and spatially smoothenedThe depth video obtained by depth camera or depth estimation software is inaccurate, which will affect the compression performance. So, a HEVC-oriented depth video preprocessing algorithm is proposed. Firstly, the edge-mask of depth video is abstracted. Secondly, the depth pixels are classified and spatially smoothened with the aid of edge-mask. Then, spatial smoothened depth video and its associated texture video are used to perform the Temporal Spatial Transform (TST), and the transformed depth video is temporally smoothened with the aid of transformed texture vide so as to enhance its temporal correlation. Finally, the temporal smoothened depth video is processed by the Inverse Temporal Spatial Transform (ITST) to get the final preprocessed depth video. The experimental results show that bit rate is saved by the depth video preprocessing algorithm, ranging from 7.00% to 23.78%, while the proposed preprocessing algorithm keeps the rendering quality of virtual view images..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 41, Issue 1, 87 (2014)
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