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Comparison of simulated backgrounds with in-orbit observations for HE, ME, and LE onboard Insight-HXMT 期刊论文 OAI收割
Astrophysics and Space Science, 2020, 卷号: 365, 页码: 158
作者: HXMT

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收藏 | 浏览/下载：48/0 | 提交时间：2022/02/08

Insight-HXMT Geant4 simulation Background observation Astrophysics - Instrumentation and Methods for Astrophysics Abstract: Insight-HXMT, the first X-ray astronomical satellite in China, aims to reveal new sources in the Galaxy and to study fundamental physics of X-ray binaries from 1 to 250 keV. It has three collimated telescopes, the High Energy X-ray telescope (HE), the Medium Energy X-ray telescope (ME), and the Low Energy X-ray telescope (LE). Before the launch, in-orbit backgrounds of these three telescopes had been estimated through Geant4 simulation, in order to investigate the instrument performance and the achievement of scientific goals. In this work, these simulated backgrounds are compared with in-orbit observations. Good agreements are shown for all three telescopes. For HE, (1) the deviation of the simulated background rate after two years of operation in space is 5 % from the observation (2) the total background spectrum and the relative abundance of the 67 keV line show long-term increases both in simulations and observations. For ME, (1) the deviation of simulated background rate is within 15 % from the observation, and (2) there are no obvious long-term increase features in the background spectra of simulations and observations. For LE, the background level given by simulations is also consistent with observations. The consistencies of these comparisons validate that the Insight-HXMT mass model, i.e., space environment components and models adopted, physics processes selected, and detector constructions built, is reasonable. However, the line features at 7.5 and 8.0 keV, which are obvious in the observed spectra of LE, are not evident in simulations. This might result from uncertainties in the LE constructions.

Enhanced Local Gradient Order Features and Discriminant Analysis for Face Recognition 期刊论文 OAI收割
IEEE TRANSACTIONS ON CYBERNETICS, 2016, 卷号: 46, 期号: 11, 页码: 2656-2669
作者: Ren, Chuan-Xian; Lei, Zhen; Dai, Dao-Qing; Li, Stan Z.

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收藏 | 浏览/下载：22/0 | 提交时间：2017/02/14

Discontinuity Image Gradient Order Features Sparse Representation Subspace Learning

Research on load-bearing characteristics of precision air-bearing rotary stage (EI CONFERENCE) 会议论文 OAI收割
3rd international Conference on Manufacturing Science and Engineering, ICMSE 2012, March 27, 2012 - March 29, 2012, Xiamen, China
作者: Wang L.; Wang L.; Wang L.; Lin J.

收藏 | 浏览/下载：114/0 | 提交时间：2013/03/25

Air-bearing is a core component of air-bearing rotary stage. The weakness that the air-bearing has the low load capacity and stiffness has been concerned about by domestic and foreign scholars. So how to improve the load capacity and stiffness has become a serious problem. In order to improve the load capacity and stiffness of the air-bearing rotary stage in this paper we improved structure of Zhang Wenjie and others' high-precision direct-drive air-bearing rotary stage. The gas film of air-bearing has been meshed by GAMBIT software and we use FLUENT software to obtain the carrying capacity features of the gas film. Finally the structural static force of the precision air-bearing rotary stage will be analyzed by ANSYS software. The analysis results show that: the structural design of the precision air-bearing rotary stage is reasonable and this structure can provide a larger range of loads. Even in heavy load conditions a larger deformation will not occur any more. It has a good practical value and also can be widely used in high precision equipments. (2012) Trans Tech Publications.

Multi-focus image fusion algorithm based on adaptive PCNN and wavelet transform (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Imaging Detectors and Applications, May 24, 2011 - May 26, 2011, Beijing, China
Wu Z.-G.; Wang M.-J.; Han G.-L.

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Being an efficient method of information fusion image fusion has been used in many fields such as machine vision medical diagnosis military applications and remote sensing.In this paper Pulse Coupled Neural Network (PCNN) is introduced in this research field for its interesting properties in image processing including segmentation target recognition et al. and a novel algorithm based on PCNN and Wavelet Transform for Multi-focus image fusion is proposed. First the two original images are decomposed by wavelet transform. Then based on the PCNN a fusion rule in the Wavelet domain is given. This algorithm uses the wavelet coefficient in each frequency domain as the linking strength so that its value can be chosen adaptively. Wavelet coefficients map to the range of image gray-scale. The output threshold function attenuates to minimum gray over time. Then all pixels of image get the ignition. So the output of PCNN in each iteration time is ignition wavelet coefficients of threshold strength in different time. At this moment the sequences of ignition of wavelet coefficients represent ignition timing of each neuron. The ignition timing of PCNN in each neuron is mapped to corresponding image gray-scale range which is a picture of ignition timing mapping. Then it can judge the targets in the neuron are obvious features or not obvious. The fusion coefficients are decided by the compare-selection operator with the firing time gradient maps and the fusion image is reconstructed by wavelet inverse transform. Furthermore by this algorithm the threshold adjusting constant is estimated by appointed iteration number. Furthermore In order to sufficient reflect order of the firing time the threshold adjusting constant is estimated by appointed iteration number. So after the iteration achieved each of the wavelet coefficient is activated. In order to verify the effectiveness of proposed rules the experiments upon Multi-focus image are done. Moreover comparative results of evaluating fusion quality are listed. The experimental results show that the method can effectively enhance the edge details and improve the spatial resolution of the image. 2011 SPIE.

Study of experimental design and Response Surface method for surrogate model of computational simulation (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
Xi R.; Jia H.; Xiao Q.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

While the high-precision simulation is widely used in science and technology Design of Experiment (DOE) based on Response Surface (RS) method can be employed in surrogate model to reduce the cost and error. In order to illustrate the relationship between parameters and response features several DOE methods and Response Surface (RS) method are studied. The author used polynomial regression and RBF neural network based on orthogonal array to build a rocket aerodynamic discipline surrogate model respectively which proved their feasibility. From the results of the test case conclusion is drawn that characteristic as well as acclimatization of DOE methods and different approximation should be considered for different issues so the factors of cost and accuracy could reach a balance synthetically. 2011 IEEE.

An improved algorithm to generate high quality progressive animation models (EI CONFERENCE) 会议论文 OAI收割
2010 International Conference on Biomedical Engineering and Computer Science, ICBECS 2010, April 23, 2010 - April 25, 2010, Wuhan, China
作者: Zhao J.; Zhang S.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

In computer graphics investigation has been made in many years in progressive models generation to alleviate the workload of visualization processing. However most of the existing algorithms only focus on static meshes and very little works are to deal with animation models. In this paper we propose an improved method for generating progressive multiresolution animation models. By the method we first use a normal deviation parameter to improve the famous QEM method as our basic edge contraction metric to generate a base hierarchy. The sequence of the simplified models is generated progressively from the first frame to the last one. Based on the edge contraction sequence in the previous frame the contraction order in the current frame is adjusted according to the deformation degree. We demonstrate that our method works efficiently and can generate better approximations with well-preserved features than previous methods. 2010 IEEE.

A new algorithm to approximate deforming models based on torsion detection (EI CONFERENCE) 会议论文 OAI收割
2010 6th International Conference on Wireless Communications, Networking and Mobile Computing, WiCOM 2010, September 23, 2010 - September 25, 2010, Chengdu, China
作者: Zhang S.; Wang G.

收藏 | 浏览/下载：25/0 | 提交时间：2013/03/25

In this paper we propose a new method to approximate deforming models based on torsion detection. We propose the use of surface torsion to represent local features on the original model and consider it as an additional weight factor when calculating the edge contraction cost during the simplification process. The approximations of the original deforming models are generated progressively from the first frame to the last one. Based on the edge contraction sequence in the previous frame the contraction order in the current frame is adjusted according to the deformation degree. Our approach is fast easy to implement and as a result good quality approximations with well-preserved fine details can be generated at any given frame. 2010 IEEE.

A study of automation recognition of bridge in SAR image (EI CONFERENCE) 会议论文 OAI收割
2010 International Conference on Computer, Mechatronics, Control and Electronic Engineering, CMCE 2010, August 24, 2010 - August 26, 2010, Changchun, China
作者: Zhang L.-P.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

According to river and bridge features in SAR (Synthetic Aperture Radar SAR) image as well as the position relationship between bridge and river the automatic recognition method of bridge is presented. First the gradient of an image is calculated by gradient operator in order to get the gradient image and river region is segmented by Fisher criterion. Then a doubtful bridge region is extracted by morphology method and segmented by Fisher criterion. Finally the bridge is recognized according to the features. Experimental results show that this method can automatically and rapidly recognize bridge. 2010 IEEE.

Mean shift tracking combining SIFT (EI CONFERENCE) 会议论文 OAI收割
2008 9th International Conference on Signal Processing, ICSP 2008, October 26, 2008 - October 29, 2008, Beijing, China
作者: Xue C.

收藏 | 浏览/下载：65/0 | 提交时间：2013/03/25

A novel visual tracking algorithm to cope with occlusion and scale variation is proposed. This method combines mean shift and SIFT algorithm to track object. SIFT algorithm is invariant to rotation translation and scale variation. But it is a timeconsuming algorithm. The wasting time is related to image size. So the proposed algorithm first adopts mean shift to initially locate object position then SIFT operator is used to detect features in object area and model area lastly the proposed method matches features in these two areas and calculates the relationship between them using affine transform. According to affine transform parameters the state of object can be adjusted in time. In order to reduce process time an improved feature matching algorithm is proposed in this paper. Experiments show that the proposed algorithm deals with occlusion successfully and can adjust object size in time. 2008 IEEE.

Stochastic video signal's automatic identification and image reproduction (EI CONFERENCE) 会议论文 OAI收割
2007 2nd IEEE Conference on Industrial Electronics and Applications, ICIEA 2007, May 23, 2007 - May 25, 2007, Harbin, China
Mingxiu L.; Guangliang H.

收藏 | 浏览/下载：18/0 | 提交时间：2013/03/25

In order to realize the automatic extraction of stochastic signal's horizontal synchronization frequency and the stable reproduction of video image different image features of horizontal synchronization blanking signal under different deviation are analyzed and spectrum analysis algorithm of horizontal synchronization frequency texture feature extraction algorithm of slope image and phase feature extraction algorithm of drifting image are put forward. Based on the three algorithms the hierarchical automatic recognition algorithm is put forward to automatically control the adjusting of the horizontal synchronization frequency and realize the reproduction. The algorithm was applied in the automatic interception system of computer video leaking information and quick interception and stable reproduction of computer video leaking information were achieved. 2007 IEEE.