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Synchronous X-ray/Optical QPOs from the Black Hole LMXB MAXI J1820+070 期刊论文 OAI收割
Monthly Notices of the Royal Astronomical Society, 2021
作者: HXMT

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black hole physics Low Mass X-ray Binaries accretion accretion discs stars: individual (MAXI J1820+070) Astrophysics - High Energy Astrophysical Phenomena Abstract: We present high-speed optical photometry from SAAO and SALT on the black hole LMXB MAXI J1820+070 (ASSASN-18ey), some of it simultaneous with NICER, Swift and Insight-HXMT X-ray coverage. We detect optical Quasi-Periodic Oscillations (QPOs) that move to higher frequencies as the outburst progresses, tracking both the frequency and evolution of similar X-ray QPOs previously reported. Correlated X-ray/optical data reveal a complex pattern of lags, including an anti-correlation and a sub-second lag that evolve over the first few weeks of outburst. They also show correlated components separated by a lag equal to the QPO period roughly centered on zero lag, implying that the inter-band variability is strongly and consistently affected by these QPOs at a constant phase lag of roughly ±Ю The synchronisation of X-ray and optical QPOs indicates that they must be produced in regions physically very close to each other we thus propose that they can be explained by a precessing jet model, based on analogies with V404 Cyg and MAXI J1348-630.

Stray light analysis of solar photoelectric detection system on space target (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Intelligent System and Applied Material, GSAM 2012, January 13, 2012 - January 15, 2012, Taiyuan, Shanxi, China
Li L.-Y.; Wang Y.-F.; San X.-G.

收藏 | 浏览/下载：148/0 | 提交时间：2013/03/25

Most conventional spacious solar photoelectric detection systems suffer from unexpected stray light. This paper demonstrates the effects on photoelectric detection system bring out by stray light. On this foundation build up evaluation index of stray light system to search the reasonable programme to eliminating stray light. A detailed telescope system geometry model was created and scatter models were create for telescope and enclosure components. By the means of designing the structure of main baffle baffle vane and the coating technology. In order to verify the prosperity of structure that designed we utilizes software to analysis opto-mechanical model. we utilizes software to analysis opto-mechanical model. The simulations show that point source transmittance of the system is thus reduced by up to two orders of magnitude between 10-8 and 10-10. Meanwhile the experiment obtains clean detection data which satisfies the system requirements. Stray light has been suppressed effectually and so measurement precision was improved from detection graphics. (2012) Trans Tech Publications.

A hybrid median filter for enhancing dim small point targets and its fast implementation (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Multimedia and Signal Processing, CMSP 2011, May 14, 2011 - May 15, 2011, Guilin, Guangxi, China
Yang Q.

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Weak stars and middle altitude orbit satellites or high altitude orbit satellites are presented as dim point targets in images of astronomical observation. They have low intensity and occupy few pixels in image. In most situations the background of sky is always ununiform and there exists pulse noises. Thus results in targets submerging in background noises and low signal noise ratio (SNR). Median filter is an effective method for removing pulse noise. But it can blur image after modifying gray of non-noise pixels when image has low SNR. A hybrid median filter algorithm is proposed to process low SNR dim point targets image. The newly proposed method can suppress the pulse noises also can increase target $SNR$ and does not add extra fake targets. The time complexity of median filter is O(N2)(N is the widow size) and is difficult to implement in hardware. For quasi real time application a fast implementation of our hybrid median filter is proposed to reduce the time complexity to O(N). Experimental results show that the newly proposed algorithm is superior to ordinary median filter and fast median filter by comparing visual effect and performance. 2011 IEEE.

The research on adaptive measurement of angular acceleration for photoelectric servo turntable (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Mechatronic Science, Electric Engineering and Computer, MEC 2011, August 19, 2011 - August 22, 2011, Jilin, China
作者: Guo J.; Chen J.; Guo J.

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The paper proposes a new measurement method of angular acceleration for photoelectric servo turntable. Piezoelectric angular acceleration sensor is used to measure angular acceleration directly Adaptive FIR filter based on LMS algorithm is established on DSP by which angular acceleration signal can be filtered and corrected errors adaptively then angular acceleration signals can be measured adaptively. This method avoids measurement errors and calculation noise by computing angular acceleration indirectly thus improving measurement precision and making measurement results better than traditional methods. The gotten angular acceleration can be sent to servo control mechanism as feed forward control signals to improve control effects of servo turntable significantly. 2011 IEEE.

The new approach for infrared target tracking based on the particle filter algorithm (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Infrared Imaging and Applications, May 24, 2011 - May 24, 2011, Beijing, China
作者: Sun H.; Han H.-X.; Sun H.

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Target tracking on the complex background in the infrared image sequence is hot research field. It provides the important basis in some fields such as video monitoring precision and video compression human-computer interaction. As a typical algorithms in the target tracking framework based on filtering and data connection the particle filter with non-parameter estimation characteristic have ability to deal with nonlinear and non-Gaussian problems so it were widely used. There are various forms of density in the particle filter algorithm to make it valid when target occlusion occurred or recover tracking back from failure in track procedure but in order to capture the change of the state space it need a certain amount of particles to ensure samples is enough and this number will increase in accompany with dimension and increase exponentially this led to the increased amount of calculation is presented. In this paper particle filter algorithm and the Mean shift will be combined. Aiming at deficiencies of the classic mean shift Tracking algorithm easily trapped into local minima and Unable to get global optimal under the complex background. From these two perspectives that "adaptive multiple information fusion" and "with particle filter framework combining" we expand the classic Mean Shift tracking framework.Based on the previous perspective we proposed an improved Mean Shift infrared target tracking algorithm based on multiple information fusion. In the analysis of the infrared characteristics of target basis Algorithm firstly extracted target gray and edge character and Proposed to guide the above two characteristics by the moving of the target information thus we can get new sports guide grayscale characteristics and motion guide border feature. Then proposes a new adaptive fusion mechanism used these two new information adaptive to integrate into the Mean Shift tracking framework. Finally we designed a kind of automatic target model updating strategy to further improve tracking performance. Experimental results show that this algorithm can compensate shortcoming of the particle filter has too much computation and can effectively overcome the fault that mean shift is easy to fall into local extreme value instead of global maximum value.Last because of the gray and fusion target motion information this approach also inhibit interference from the background ultimately improve the stability and the real-time of the target track. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

Realization of auto-focusing system for cameras based on TMS320F2812 DSP (EI CONFERENCE) 会议论文 OAI收割
2nd Annual Conference on Electrical and Control Engineering, ICECE 2011, September 16, 2011 - September 18, 2011, Yichang, China
作者: Zhang T.

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Focusing systems play an important role in a variety of optical measurements and detection instruments. In this paper several kinds of auto-focusing methods were described and the relevant focusing evaluation functions were introduced based on image processing methods. An auto-focusing system based on image processing was designed by using the TMS320F2812 digital signal processing chip as a platform. Moreover some problem and solutions about auto-focusing system was demonstrated. The system designed in this paper can find the good image plane in 10 steps (about 5 second) thus it can meet the requirements of practical applications. 2011 IEEE.

Study on the flutter model of the imaging quality of TDICCD space camera (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Advanced Engineering Materials and Technology, AEMT 2011, July 29, 2011 - July 31, 2011, Sanya, China
作者: Chen X.; Chen X.; Chen X.

收藏 | 浏览/下载：31/0 | 提交时间：2013/03/25

For any On-orbit Space camera the influence of flutter on the imaging process of TDICCD space camera is inevitable thus causing the decline of image quality. This paper briefly introduces the principle of TIDCCD camera and how flutter affects the imaging process. Then through the analysis and calculation of practical program we find the acceleration criterion to avoid the blur of image quality. (2011) Trans Tech Publications.

Neural network based online traffic signal controller design with reinforcement training (EI CONFERENCE) 会议论文 OAI收割
14th IEEE International Intelligent Transportation Systems Conference, ITSC 2011, October 5, 2011 - October 7, 2011, Washington, DC, United states
Dai Y.; Hu J.; Zhao D.; Zhu F.

收藏 | 浏览/下载：31/0 | 提交时间：2013/03/25

Traffic congestion leads to problems like delays decreasing flow rate and higher fuel consumption. Consequently keeping traffic moving as efficiently as possible is not only important to economy but also important to environment. Traffic system is a large complex nonlinear stochastic system. Traditional mathematical methods have some limitations when they are applied in traffic control. Thus computational intelligence (CI) technologies gain more and more attentions. Neural Networks (NNs) is a well developed CI technology with lots of promising applications in traffic signal control (TSC). In this paper a neural network (NN) based signal controller is designed to control the traffic lights in an urban traffic road network. Scenarios of simulation are conducted under a microscopic traffic simulation software. Several criterions are collected. Results demonstrate that through online reinforcement training the controllers obtain better control effects than the widely used pre-time and actuated methods under various traffic conditions. 2011 IEEE.

Research on image restoration of Roll-Swing imaging seeker (EI CONFERENCE) 会议论文 OAI收割
3rd IEEE International Conference on Advanced Computer Control, ICACC 2011, January 18, 2011 - January 20, 2011, Harbin, China
作者: Zhang H.; Zhang H.

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To achieve a correct image receiving for Roll-Swing imaging seeker the mechanism and imaging process is analyzed. The causes of image rotation are discussed. The influence of the frame encoders' precision on imaging de-rotation quality is analyzed. The Roll-Swing imaging seeker is designed for high-speed aerocraft thus the received images are greatly degraded due to atmospheric turbulence. A new method of image restoration is proposed for turbulence-degraded images in this paper. The method is to get point spread function (PSF) based on the estimation of optical transfer function (OTF) according to the optical system design simulation. Finally to obtain the restored image constrained least squares filtering is used with the known PSF. The experiment results indicate that the new restoration method has a favorable effect to satisfy requirement of the automatic target recognition. 2011 IEEE.

MTF-based research on the minimum fill factor in optical sparse aperture system (EI CONFERENCE) 会议论文 OAI收割
2011 4th International Conference on Intelligent Computation Technology and Automation, ICICTA 2011, March 28, 2011 - March 29, 2011, Shenzhen, Guangdong, China
作者: Liu Z.

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To avoid the loss of image information when it is transferred through optical sparse aperture system with excessively diluted apertures arrangement we propose a method in the frequency domain termed characteristic triangle to calculate the minimum fill factor. This method is based on the characteristics of MTF and demonstrates that when the characteristic triangle is equilateral with each side 3th power of sub-MTF cutoff frequency MTF has no zero value below cutoff frequency thus we can obtain the minimum fill factor. Furthermore we apply it to some typical sparse arrays such as Golay3 Golay6 Ring6 and Tri-arm7 and get their fill factors of 33.33% 15.16% 30.11% and 11.14% correspondingly which are consistent with numerical results. 2011 IEEE.