中国科学院机构知识库网格系统: 检索

Design and Locomotion Control of a Dactylopteridae-Inspired Biomimetic Underwater Vehicle With Hybrid Propulsion 期刊论文 OAI收割
IEEE TRANSACTIONS ON AUTOMATION SCIENCE AND ENGINEERING, 2021, 页码: 13
作者: Zhang, Tiandong; Wang, Rui; Wang, Yu; Cheng, Long; Wang, Shuo

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收藏 | 浏览/下载：27/0 | 提交时间：2022/01/27

Propulsion DC motors Robots Control systems Servomotors Underwater vehicles Sports Biomimetic underwater vehicle (BUV) body and or caudal fin (BCF) median and or paired fin (MPF) hybrid propulsion central pattern generators (CPGs) fuzzy proportion integral differential (PID)

Constraining the X-Ray-Infrared Spectral Index of Second-timescale Flares from SGR 1935+2154 with Palomar Gattini-IR 期刊论文 OAI收割
The Astrophysical Journal, 2020, 卷号: 901, 页码: L7
作者: HXMT

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收藏 | 浏览/下载：22/0 | 提交时间：2022/02/08

Radio transient sources Magnetars Soft gamma-ray repeaters 2008 992 1471 Astrophysics - High Energy Astrophysical Phenomena Astrophysics - Instrumentation and Methods for Astrophysics Abstract: The Galactic magnetar SGR 1935+2154 has been reported to produce the first example of a bright millisecond-duration radio burst (FRB 200428) similar to the cosmological population of fast radio bursts (FRBs). The detection of a coincident bright X-ray burst represents the first observed multiwavelength counterpart of an FRB. However, the search for similar emission at optical wavelengths has been hampered by the high inferred extinction on the line of sight. Here, we present results from the first search for second-timescale emission from the source at near-infrared (NIR) wavelengths using the Palomar Gattini-IR observing system in the J band, enabled by a novel detector readout mode that allows short exposure times of ?0.84 s with 99.9% observing efficiency. With a total observing time of ?12 hr (?47,728 images) during its 2020 outburst, we place median 3Ҡlimits on the second-timescale NIR fluence of ?18 Jy ms (13.1 AB mag). The corresponding extinction-corrected limit is ?125 Jy ms for an estimated extinction of A_J = 2.0 mag. Our observations were sensitive enough to easily detect an NIR counterpart of FRB 200428 if the NIR emission falls on the same power law as observed across its radio to X-ray spectrum. We report nondetection limits from epochs of four simultaneous X-ray bursts detected by the Insight-HXMT and NuSTAR telescopes during our observations. These limits provide the most stringent constraints to date on fluence of flares at 10¹⁴ Hz, and constrain the fluence ratio of the NIR emission to coincident X-ray bursts to R_NIR ? 0.025 (fluence index ?0.35).

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.

收藏 | 浏览/下载：20/0 | 提交时间：2013/03/25

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.

Research on infrared dim-point target detection and tracking under sea-sky-line complex background (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: Dong Y.-X.; Zhang H.-B.; Li Y.; Li Y.; Li Y.

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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).

The corner detector of teeth image based on the improved SUSAN algorithm (EI CONFERENCE) 会议论文 OAI收割
3rd International Conference on BioMedical Engineering and Informatics, BMEI 2010, October 16, 2010 - October 18, 2010, Yantai, China
作者: Yang L.; Yang L.; Wang X.; Wang X.; Wang X.

收藏 | 浏览/下载：17/0 | 提交时间：2013/03/25

In order to detect the corners of the teeth image secondly last we detected the corners of the image through the improved SUSAN corner detector algorithm. Through lots of experiments and comparing with other corner detector methods which were acquired by oral cavity endoscope we segmented the image by the threshold based on the gray value of the image this method can detect the corners of the teeth image effectively in this paper which can offer some available parameters for the 3D reconstruction of the teeth. 2010 IEEE. we used the improved SUSAN corner detector algorithm. In this method firstly we removed the noise of the image by the morphology open operation and median filtering

The research of corner detector of teeth image based on the curvature scale space corner algorithm (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: Yang L.; Wang X.; Wang X.; Wang X.; Yang L.

收藏 | 浏览/下载：18/0 | 提交时间：2013/03/25

In order to detect the corners of the teeth image secondly thirdly last this method can detects the corners of the teeth image effectively which were acquired by oral cavity endoscope we segmented the image by the threshold based on the gray value of the image we detected the edge of the teeth image by the Canny edge detector we detected the corners by the adaptive threshold curvature scale corner detector. Through lots of experiments and we compare this method to other corner detector methods which offers some available parameters for the 3D reconstruction of the teeth. 2010 IEEE. in this paper we used the CSS algorithm. In this method firstly we removed the noise of the image by the morphology open operation and median filtering

Sort optimization algorithm of median filtering based on FPGA (EI CONFERENCE) 会议论文 OAI收割
2010 International Conference on Machine Vision and Human-Machine Interface, MVHI 2010, April 24, 2010 - April 25, 2010, Kaifeng, China
作者: Li S.

收藏 | 浏览/下载：28/0 | 提交时间：2013/03/25

The traditional sorting algorithm of median filtering is optimized according to the hardware structure features of FPGA. FPGA is used to acquire the data parallelly for comparing the data of the same column in the median filtering window. Comparing results shared by adjacent filter window are saved temporarily to match the new round of median filtering by using FPGA internal resources. This method can reduce the comparing times from current 21 down to 13 and improve the algorithm efficiency nearly 40%.The experimental results prove that the optimized algorithm can filter a 1K1K gray-level image in about 20ms which ensure the proposed algorithm can be applied in the real-time image median filtering system. 2010 IEEE.

Extracting sea-sky-line based on improved local complexity (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 Y.-F.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

Sea-sky-line extraction under complicated sea-sky background is an important aspect of long-range target tracking research. An algorithm based on improved local complexity is proposed according to the feature that the sky and the sea usually show up at different gray levels in sea-sky background images. Median filter is applied first to remove peak noise and then the point set of sea-sky-line region which has the greatest change in image is obtained by calculating the local complexity of image and selecting a segmentation threshold. Finally Hough transform is used to extract the sea-sky-line. The experiment results indicate that this method can extract sea-sky-line under simple and complicated sea-sky backgrounds which is robust and can improve noise immunity of the algorithm. 2010 IEEE.

Design of real-time small target detection system for infrared image based on FPGA (EI CONFERENCE) 会议论文 OAI收割
2010 International Conference on Optics, Photonics and Energy Engineering, OPEE 2010, May 10, 2010 - May 11, 2010, Wuhan, China
作者: Liu J.; Sun Q.; Wang J.; Ye X.; Xu H.

收藏 | 浏览/下载：24/0 | 提交时间：2013/03/25

A simple detection measurement is developed for realtime small target detection in infrared background which can be easily available on FPGA. Basing on the difference between target and background a predictive background is generated via restraining the infrared background with median filter and then global threshold segmentation is used to residual image for further processing. Taking advantage of the relationship of targets in frames a comprehensive analysis of residual image is made and then the precise position of target is got by removing pseudo-objectives. Experiment results show that the method is simple to apply to hardware system improve the system's false alarm rate and meet the requirements of practical engineering. 2010 IEEE.

The design of acquisition circuit for grating digital signal based on FPGA (EI CONFERENCE) 会议论文 OAI收割
2010 3rd International Conference on Advanced Computer Theory and Engineering, ICACTE 2010, August 20, 2010 - August 22, 2010, Chengdu, China
作者: Wang W.-G.

收藏 | 浏览/下载：36/0 | 提交时间：2013/03/25

In order to resolve the poor suppression capability of noise and fitter interference existing in grating encoder high-rate subdivision and the poor accuracy of kam-to counting circuit the results show that the design method will help improve the controlled object of measurement precision and control accuracy. 2010 IEEE. we design a circuit based on FPGA to realize multiplier kam and filter for the output of two-way orthogonal signal generated by Incremental Optical Encoder. The system is mainly divided into three modules such as filtering multiplier kam-to and counting. The main function of filter circuit is to eliminate the jitter and noise interference existing in the quadrate encoder signals. Kam-to multiplier circuit can accurately judge the full cycle and half-cycle of incremental encoder at the same time can make fourfold multiplier. Counting circuit can use IP cores owned by Quartus II which is not restricted on the median. At last timing simulation based on Modelsim carried on the three modules