分类: 生物学 >> 生物物理学 提交时间: 2016-05-12
摘要: Synthetic aperture radar (SAR) provides a powerful surveillance capability allowing the observation of target, independently from weather effects and from the day and night cycle. Unfortunately, the automatic interpretation of SAR images is often complicated and time consuming. In support of real-time vessel monitoring, a fast line-scanning detector designed for detecting ships from SAR imagery is proposed in this paper. The detector does not require any prior knowledge about ships and background observation. It uses a novel local gray-level gathering degree algorithm to detect potential targets and then a complementary filtering scheme to reject false alarms. The performance analysis over real SAR images confirms that the proposed detector works well in various circumstances with high detection rate, fast detection speed and perfect shape preservation.
分类: 物理学 >> 核物理学 提交时间: 2023-10-07
摘要: In the RD for upgrading the KL0and detector (KLM) in Belle II experiment using scintillator and silicon photomultiplier (SiPM), we design a compact preamplifier with high#2;speed and low-noise. The preamplifier has a good gain stability, a baseline noise level of 0.3 mV, a good time resolution that can achieve < 20 ps, and can be applied comprehensively to SiPMs. To reduce the pile-up in using a large size SiPM or an array of SiPMs, which is due to the large capacitance and high dark count rate, we adopt pole#2;zero-cancellation which reduce both the rise time and the fall time of a SiPM signal. The combinations of the preamplifier and several kinds of SiPMs show time resolutions better than 50 ps for most of the cases; when the number of detected photons is larger than 60, a time resolution of about 25 ps can be achieved