中国开放科研知识云: 检索

Structural amelioration of 920 nm optically pumped semiconductor vertical external-cavity surface emitting laser (OPS-VECSEL) (EI CONFERENCE) 会议论文
2nd International Conference on Energy, Environment and Sustainable Development, EESD 2012, October 12, 2012 - October 14, 2012, Jilin, China
Liang X.; Wang L.; Ning Y.; Liu Y.

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920 nm optically pumped semiconductor vertical external-cavity surface emitting laser (OPS-VECSEL) has an important application in laser display. We constructed and optimized a 920 nm OPS-VECSEL with active region of In0.09Ga0.91As quantum well (QW) system pumped by 808 nm laser diode module. By the finite element method self-consistent solutions of the semiconductor electronic and optical equations are realized to calculate the characteristics parameters of OPS-VECSEL. The performances of device especially the mode the threshold and the optical-optical translation efficiency were analyzed by dealing with different number of QWs (1 2 and 3) in one period QW depth barrier width the component and dimension of the non-absorption layer. We chose an improved structure of them. On this basis we ameliorated the number of QW periods and the simulation showed that in order to obtain high performance device the choice of the number of QW periods must be cautious. (2013) Trans Tech Publications Switzerland.

Image quality assessment based on gradient complex matrix (EI CONFERENCE) 会议论文
2012 International Conference on Systems and Informatics, ICSAI 2012, May 19, 2012 - May 20, 2012, Yantai, China
Wang Y.

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An image quality assessment model based on gradient complex matrix is proposed. The vertical and horizontal gradient information of grayscale image is calculated. Complex number is used to construct the measuring matrix. Singular value decomposition is performed in order to obtain the main structure information of the image. The singular value feature vectors of the image gradient complex matrices corresponding to the reference image and the distorted image are used to measure the structural similarity of the two images. PSNR is taken as a tool to evaluate the gradient distribution similarity. Their properties are analyzed by using LIVE database and nonlinearity regression function. 2012 IEEE.

Research on infrared dim-point target detection and tracking under sea-sky-line complex background (EI CONFERENCE) 会议论文
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Infrared Imaging and Applications, May 24, 2011 - May 24, 2011, Beijing, China
Dong Y.-X.; Li Y.; Zhang H.-B.

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Target detection and tracking technology in infrared image is an important part of modern military defense system. Infrared dim-point targets detection and recognition under complex background is a difficulty and important strategic value and challenging research topic. The main objects that carrier-borne infrared vigilance system detected are sea-skimming aircrafts and missiles. Due to the characteristics of wide field of view of vigilance system the target is usually under the sea clutter. Detection and recognition of the target will be taken great difficulties.There are some traditional point target detection algorithms such as adaptive background prediction detecting method. When background has dispersion-decreasing structure the traditional target detection algorithms would be more useful. But when the background has large gray gradient such as sea-sky-line sea waves etc.The bigger false-alarm rate will be taken in these local area.It could not obtain satisfactory results. Because dim-point target itself does not have obvious geometry or texture feature in our opinion from the perspective of mathematics the detection of dim-point targets in image is about singular function analysis.And from the perspective image processing analysis the judgment of isolated singularity in the image is key problem. The foregoing points for dim-point targets detection its essence is a separation of target and background of different singularity characteristics.The image from infrared sensor usually accompanied by different kinds of noise. These external noises could be caused by the complicated background or from the sensor itself. The noise might affect target detection and tracking. Therefore the purpose of the image preprocessing is to reduce the effects from noise also to raise the SNR of image and to increase the contrast of target and background. According to the low sea-skimming infrared flying small target characteristics the median filter is used to eliminate noise improve signal-to-noise ratio then the multi-point multi-storey vertical Sobel algorithm will be used to detect the sea-sky-line so that we can segment sea and sky in the image. Finally using centroid tracking method to capture and trace target. This method has been successfully used to trace target under the sea-sky complex background. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

Design and test of focusing mechanism of space camera (EI CONFERENCE) 会议论文
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Design, Manufacturing, and Testing of Micro- and Nano-Optical Devices and Systems, April 26, 2010 - April 29, 2010, Dalian, China
Guo Q.; Jin G.; Dong J.; Li Y.; Li W.; Wang H.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

According to the focal depth and work environment of a space camera a focusing mechanism is designed which consists of precision screw ball transmission and linear bearing guidance and accuracy improving. The dynamic- strike- resistance adaptability to temperature and vacuum are considered into the reliable design method. Furthermore the linearity error the structure stability and the mechanism work situation in high and low temperature are tested. The result is that the linearity error of the mechanism is less than 0.003 mm and the sway error of vertical way and level way of the mirror is less than 20''. The linearity error of the mechanism and the sway error of the mirror remain unchanged after vibration test. The mechanism can work in the complex space environment. 2010 SPIE.

Study on dynamic imaging on TDI CCD optical remote sensor of push-broom technology (EI CONFERENCE) 会议论文
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, April 26, 2010 - April 29, 2010, Dalian, China
Gao M.-H.; Zhao G.-J.; Liu L.; Ren J.-Y.

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A set special detecting system is proposed based on TDICCD push-broom technology applying in dynamic imaging detecting experiment of space optics remote sensor. In the system In the course of detecting push-broom movement of the satellite is simulated through using double supporting U structure precision rotary platform with remote sensor by angular speed 0.555/s regard Nyquist frequency target as detecting aim within the range of 5 and control precision on steady speed achieves 0.3% in order to solve matching uncertainty between the CCD pixel and the vertical target strip image when the remote sensor does push-broom make matching simplify enhance the measurement result the accuracy. So the tolerance a/n arithmetic progression gap target strip is joined in each group of rectangular vertical group target strip. The remote sensor obtains in vertical the level and 45 the direction 0 fields of view 0.86 the field of view Nyquist frequency target strip image after detected a group target strip which can precision matching to TDICCD pixel at least can be obtained through analysis and dealing with 0.86 field of view's target strip image. The experiment not only verifies the detecting system's feasibility but simultaneously verifies whether to have the high quality dynamic imaging quality when TDICCD push-broom technology is adopted on the remote sensor developed. 2010 Copyright SPIE - The International Society for Optical Engineering.

Vertical-external-cavity surface-emitting lasers: Numerical simulation, and characterization (EI CONFERENCE) 会议论文
Optoelectronic Materials and Devices III, October 27, 2008 - October 30, 2008, Hangzhou, China
Yan C.; He C.; Lu G.; Qin L.

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Firstly the vertical external-cavity surface-emiting lasers (VECSELs) device structure and model was given and the output characteristic was simple calculated. Then in experiment the VECSELs were grown bonded on to the heat sink and optically pumped by high-power 808nm diode laser array with fiber output module the light emission spectra were measured. Finally The thermal characteristic of the VECSELs was investigated by changing the temperature of the substrate. 2008 SPIE.

Driving techniques for high frame rate CCD camera (EI CONFERENCE) 会议论文
Electronic Imaging and Multimedia Technology V, November 12, 2007 - November 15, 2007, Beijing, China
Guo W.; Jin L.; Xiong J.

收藏 | 浏览/下载：24/0 | 提交时间：2013/03/25

This paper describes a high-frame rate CCD camera capable of operating at 100 frames/s. This camera utilizes Kodak KAI-0340 an interline transfer CCD with 640(vertical)480(horizontal) pixels. Two output ports are used to read out CCD data and pixel rates approaching 30 MHz. Because of its reduced effective opacity of vertical charge transfer registers interline transfer CCD can cause undesired image artifacts such as random white spots and smear generated in the registers. To increase frame rate a kind of speed-up structure has been incorporated inside KAI-0340 then it is vulnerable to a vertical stripe effect. The phenomena which mentioned above may severely impair the image quality. To solve these problems some electronic methods of eliminating these artifacts are adopted. Special clocking mode can dump the unwanted charge quickly then the fast readout of the images cleared of smear follows immediately. Amplifier is used to sense and correct delay mismatch between the dual phase vertical clock pulses the transition edges become close to coincident so vertical stripes disappear. Results obtained with the CCD camera are shown.