中国科学院机构知识库网格系统: 检索

浏览/检索结果: 共7条，第1-7条

帮助

条数/页：排序方式：
	Microwave Pulse-Coherent Technique-Based Clock With a Novel Magnetron-Type Cavity 期刊论文 OAI收割 IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL, 2020, 卷号: 67, 期号: 4, 页码: 873-878 作者: Hao, Qiang; Xue, Wenxiang; Li, Wenbing; Xu, Feng; Wang, Xin \| 收藏 \| 浏览/下载：23/0 \| 提交时间：2020/11/09 Atomic clock frequency stability magnetron-type cavity optical pumping signal contrast
	Research on key technologies of active polarization imaging system 期刊论文 OAI收割 OPTIK, 2018, 卷号: 157, 页码: 556-564 作者: Xie Meilin; Liu Peng; Ma Caiwen; Huang Wei; Liang Jian \| 收藏 \| 浏览/下载：37/0 \| 提交时间：2018/12/11 Active Polarization Imaging Sensitivity Pulse Laser Image Contrast Signal-to-noise Ratio
	High sensitivity phase retrieval method in grating-based x-ray phase contrast imaging 期刊论文 OAI收割 MEDICAL PHYSICS, 2015, 卷号: 42, 期号: 2, 页码: 741-749 作者: Wu, Z; Gao, K; Chen, J; Wang, DJ; Wang, SH 收藏 \| 浏览/下载：34/0 \| 提交时间：2016/04/18 grating-based phase contrast imaging information extraction methods signal-to-noise ratio sensitivity
	Signal-to-noise ratio analysis of X-ray grating interferometry with the reverse projection extraction method 期刊论文 OAI收割 JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA, JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA, 2014, 2014, 卷号: 196, 196, 期号: SI, 页码: 75-79, 75-79 作者: Wu, Z; Wang, ZL; Gao, K; Wang, DJ; Wang, SH \| 收藏 \| 浏览/下载：20/0 \| 提交时间：2016/04/08 Grating-based X-ray phase contrast imaging Photon statistics Mechanical errors Signal-to-noise ratio Grating-based X-ray phase contrast imaging Photon statistics Mechanical errors Signal-to-noise ratio
	The application of adaptive enhancement algorithm based on gray entropy in mammary gland CR image (EI CONFERENCE) 会议论文 OAI收割 2012 2nd International Conference on Consumer Electronics, Communications and Networks, CECNet 2012, April 21, 2012 - April 23, 2012, Three Gorges, China Zhang M.-H.; Zhang Y.-Y. 收藏 \| 浏览/下载：34/0 \| 提交时间：2013/03/25 Mammary gland is composed entirely of soft tissue with approximate density therefore mammary gland CR medicine radiation image presents a low contrast and slight difference changes may be a manifestation of tumor so it is necessary to enhance mammary gland CR image to improve its visual quality in order to meet the demands of doctor's clinical diagnosis. However the general enhancement algorithms over enhance the contrast and noise due to image details lost aiming at the defects a mammary gland CR medicine image adaptive enhancement arithmetic based on image gray entropy is put forward. The arithmetic adapts dizzy image to magnify selected spatial frequency response in order to enhance the edge details of mammary gland CR images. It can adjust weighted factor K according to image gray characteristics namely pixel gray entropy. Experiments results demonstrate that mammary gland CR image enhanced by the algorithm has abundant details and high signal-to-noise ratio moreover CR image enhanced has good visual effect. So the method is effective and fit for enhancing CR medical radiation image edge details. 2012 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. 收藏 \| 浏览/下载：111/0 \| 提交时间：2013/03/25 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).
	Method for obtaining real temperature of space object by using the ratio of emissivity at different wavelengths (EI CONFERENCE) 会议论文 OAI收割 4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, November 19, 2008 - November 21, 2008, Chengdu, China Guo-Qiang W.; Tao C.; Jian-Li W. 收藏 \| 浏览/下载：33/0 \| 提交时间：2013/03/25 The infrared radiation character (temperature and efficiency radiation area) of a space object is an important characteristic we can judge the state of the object working in orbit by measuring temperature and variety. Due to lower temperature of the object and far distance between the object and the earth the infrared radiation signal is faintness therefore temperature and the infrared radiation character is difficult to measure. There are several methods to measure the temperature of the object in theory and each one has its applicability respectively such as applying Wien Law to compute temperature based on Stefan-Bolzmann law to compute temperature and utilizing multi-spectrum detector to measure temperature As a whole these methods are based on the hypothesis that the object is a Black-body or the radiance emissivity is constant. In fact homochromatic radiance of object is not a constant but a function that changes with wavelength. Since the problem that an object whose homochromatic radiance s not a constant which results in temperature can not be computed accurately we bring forward a method to contrast the luminance of the object at different wavelengths and deduce the relationship among homochromatic radiance and wavelength and the temperature of Black-body from which we can compute real temperature of object. 2009 SPIE.