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Improved Statistics Based positioning Scheme for Continuous Thick Crystal PET Detectors

IEEE TRANSACTIONS ON NUCLEAR SCIENCE 2013年第3期60卷 1527-1532页

作者： Wang Yonggang Cheng Xinyi Li Deng Univ Sci & Technol China State Key Lab Particle Detect & Elect Hefei 230026 Anhui Peoples R China Univ Sci & Technol China Dept Modern Phys Hefei 230026 Anhui Peoples R China

PET detectors based on continuous crystal could be an ideal alternative for current high resolution pixelated PET detectors as long as an effective positioning algorithm is provided. Statistics Based positioning (SBP) scheme has drawn much attention for its high positioning performance. However, we found that the Gaussian distribution assumption, which the two dimensional SBP (2D SBP) relies on, is inaccurate for detectors with thick crystal. The discrepancy between the assumption and the realistic situation could result in serious performance degradation. To address the problem, we propose to improve 2D SBP as ISBP (Improved Statistics Based positioning) scheme. Using our experimental data, the performance of 2D SBP and ISBP are evaluated and compared. By the event tracking method, the different behavior of 2D SBP and ISBP is revealed and analyzed. ISBP is more suitable for detectors with thick crystal. In addition, we compare the performance by ISBP and the artificial neural network position estimator using the same experimental data. The characteristics of both positioning algorithms are discussed.

关键词： ISBP Neural Network PET detector positioning algorithm SBP

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Wireless network positioning as a convex feasibility problem

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EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING 2011年第Pt.4期2011卷 1页

作者： Gholami, Mohammad Reza Wymeersch, Henk Strom, Erik G. Rydstrom, Mats Chalmers Univ Technol Dept Signals & Syst S-41296 Gothenburg Sweden

In this semi-tutorial paper, the positioning problem is formulated as a convex feasibility problem (CFP). To solve the CFP for non-cooperative networks, we consider the well-known projection onto convex sets (POCS) technique and study its properties for positioning. We also study outer-approximation (OA) methods to solve CFP problems. We then show how the POCS estimate can be upper bounded by solving a non-convex optimization problem. Moreover, we introduce two techniques based on OA and POCS to solve the CFP for cooperative networks and obtain two new distributed algorithms. Simulation results show that the proposed algorithms are robust against non-line-of-sight conditions.

关键词： wireless sensor network positioning algorithm convex feasibility problem projection onto convex sets outer approximation

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Received signal strength based positioning for multiple nodes in wireless sensor networks

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DIGITAL SIGNAL PROCESSING 2014年第0期25卷 41-50页

作者： Lin, Lanxin So, H. C. Chan, Y. T. City Univ Hong Kong Dept Elect Engn Kowloon Hong Kong Peoples R China Royal Mil Coll Canada Dept Elect & Comp Engn Kingston ON K7K 7B4 Canada

We address the problem of locating multiple nodes in a wireless sensor network with the use of received signal strength (RSS) measurements. In RSS based positioning, transmit power and path-loss factor are two environment dependent parameters which may be uncertain or unknown. For unknown transmit powers, we devise two-step weighted least squares (WLS) and maximum likelihood (ML) algorithms for node localization. The mean square error of the former is analyzed in the presence of zero-mean white Gaussian disturbances. When both transmit powers and path-loss factors are unavailable, two nonlinear least squares estimators, namely, the direct ML approach and combination of linear least squares and ML algorithm, are developed. Numerical examples are also included to evaluate the localization accuracy of the proposed estimators by comparing with two existing node positioning methods and the Cramer-Rao lower bound. (C) 2013 Elsevier Inc. All rights reserved.

关键词： Wireless sensor network Source localization Received signal strength positioning algorithm

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cMiCE: a high resolution animal PET using continuous LSO with a statistics based positioning scheme

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NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 2002年第1-3期489卷 584-598页

作者： Joung, J Miyaoka, RS Lewellen, TK Siemens Med Syst Inc Nucl Med Grp Dept Adv Res Hoffman Estates IL 60195 USA Univ Washington Dept Radiol Seattle WA 98195 USA

Objective: Detector designs for small animal scanners are currently dominated by discrete crystal implementations. However, given the small crystal cross-sections required to obtain very high resolution, discrete designs are typically expensive, have low packing fraction, reduced light collection, and are labor intensive to build. To overcome these limitations we have investigated the feasibility of using a continuous miniature crystal element (cMiCE) detector module for high resolution small animal PET applications, Methods: The detector, module consists of a single continuous slab of LSO, 25 x 25 mm(2) in exposed cross-section and 4 mm thick, coupled directly to a PS-PMT (Hamamatsu R5900-00-C12). The large area surfaces of the crystal were polished and painted with TiO2 and the short surfaces were left unpolished and painted black. Further, a new statistics based positioning (SBP) algorithm has been implemented to address linearity and edge effect artifacts that are inherent with conventional Anger style positioning schemes. To characterize the light response function (LRF) of the detector, data were collected on a coarse grid using a highly collimated coincidence setup. The LRF was then estimated using cubic spline interpolation. Detector performance has been evaluated for both SBP and Anger based decoding using measured data and Monte Carlo simulations. Results: Using the SBP scheme, edge artifacts were successfully handled, Simulation results show that the useful field of view (UFOV) was extended to similar to22 x 271 mm(2) with art average point spread function of similar to0.5 mm full width of half maximum (FWHMPSF). For the same detector with Anger decoding the UFOV of the detector was similar to16 x 16 mm(2) with an average FWHMPSP of similar to0.9 mm. Experimental results yielded similar differences between FOV and resolution performance. FWHMPSF for the SBP and Anger based method was 1.4 and 2.0 mm, uncorrected for source size, with a 1 mm diameter point

关键词： animal PET continuous LSO PS-PMT positioning algorithm

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基于有限元法的四象限探测器定位算法

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光学学报 2025年第10期45卷

作者：莫斯成闫连山叶佳邓炯斌西南交通大学信息科学与技术学院，四川成都 611756

针对传统四象限探测器定位算法在求解高斯光斑模型中的不足和挑战，提出了一种基于有限元法的改进定位方法。该方法通过将连续域的求解问题离散化为有限元可处理的数学问题，从而提高了定位精度和计算效率。仿真结果表明，所提方法在定... 详细信息

针对传统四象限探测器定位算法在求解高斯光斑模型中的不足和挑战，提出了一种基于有限元法的改进定位方法。该方法通过将连续域的求解问题离散化为有限元可处理的数学问题，从而提高了定位精度和计算效率。仿真结果表明，所提方法在定位误差方面显著优于其他算法，与传统定位算法相比，最大误差降幅可达87%。实验结果进一步验证了所提方法的有效性，所提方法在实验数据中的均方根误差达到了mm级精度，并且随着网格单元数量的增加，定位精度显著提升。综上所述，该方案在实际工程应用中具备极高的可行性与可靠性，因此其可成为四象限探测器定位的一种极具潜力的备选方案。您的浏览器不支持 audio 元素。AI语音播报关键词

关键词：四象限探测器定位算法定位精度光斑定位 quadrant detector positioning algorithm positioning accuracy spot positioning

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A crowdsourcing-based global indoor positioning and navigation system

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PERVASIVE AND MOBILE COMPUTING 2016年 31卷 94-106页

作者： Jung, Suk-hoon Lee, Sangjae Han, Dongsoo Korea Adv Inst Sci & Technol Dept Comp Sci 291 Daehak Ro Daejeon 305701 South Korea

This paper presents three key techniques to realize a global indoor positioning system (GIPS), and a global in- and-outdoor integrated navigation system (GINS). A crowdsourcing radio map construction method, a positioning algorithm for crowdsourced radio maps, and an indoor and outdoor environment detection method are developed as the three key techniques. The developed techniques have been integrated into a crowdsourcing-based indoor positioning system, named KAILOS, aiming to realize the GIPS and GINS. The system was deployed at KAIST, Daejeon campus, and now an in- and-outdoor integrated navigation service is available at KAIST campus area. The successful launch of KAILOS foretells that the GIPS and GINS are becoming a reality. (C) 2016 Elsevier B.V. All rights reserved.

关键词： Global indoor positioning and navigation Radio map positioning algorithm Crowdsourcing

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Design of an Accurate Yet Low-Cost Distributed Module for Vehicular Relative positioning: Hardware Prototype Design and algorithms

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2019年第5期68卷 4494-4501页

作者： Wang, Xinzuo Li, Wei Nanjing Univ Dept Control & Syst Engn Nanjing 210093 Jiangsu Peoples R China

In this paper, we design a modular prototype to provide relative position and orientation (RPO), with higher accuracy yet low-cost implementations. First, we design the hardware module as two distributed sub-modules: the beacon module and the receiver module. The beacon module is designed to have the rotational laser-emitting function and the wireless-broadcasting function, and the receiver module can receive both the laser signals and wireless broadcasting. Then, with these functions, we design the unique operating mechanisms for the whole module. Finally, we provide the event-triggered algorithms for the RPO measurements, which are tightly incorporated with the hardware design. Compared via experiments with other related methods, our design has more measurement capabilities, higher accuracy, and low-cost implementations on both hardware and computations. This module has potential vehicular applications, e.g., in a factory for tasks assistance.

关键词： Beacon module localization measurement modular design positioning algorithm vehicular positioning

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Survey of wireless indoor positioning techniques and systems

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IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS PART C-APPLICATIONS AND REVIEWS 2007年第6期37卷 1067-1080页

作者： Liu, Hui Darabi, Houshang Banerjee, Pat Liu, Jing Univ Illinois Dept Elect & Comp Engn Chicago IL 60612 USA Univ Illinois Dept Mech & Ind Engn Chicago IL 60607 USA

Wireless indoor positioning systems have become very popular in recent years. These systems have been successfully used in many applications such as asset tracking and inventory management. This paper provides an overview of the existing wireless indoor positioning solutions and attempts to classify different techniques and systems. Three typical location estimation schemes of triangulation, scene analysis, and proximity are analyzed. We also discuss location fingerprinting in detail since it is used in most current system or solutions. We then examine a set of properties by which location systems are evaluated, and apply this evaluation method to survey a number of existing systems. Comprehensive performance comparisons including accuracy, precision, complexity, scalability, robustness, and cost are presented.

关键词： indoor location sensing location fingerprinting positioning algorithm radio frequency (RF) wireless localization

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Investigation of bias-free positioning estimators for the scintillation cameras

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IEEE TRANSACTIONS ON NUCLEAR SCIENCE 2001年第3期48卷 715-719页

作者： Joung, J Miyaoka, RS Kohlmyer, SG Lewellen, TK Univ Washington Dept Radiol IRL Seattle WA 98105 USA

Bias-free positioning estimators for scintillation cameras are investigated. A linear correlation coefficient (LCC) and Chi square error (CSE) method are evaluated with respect to linearity and spatial resolution performance. The LCC method uses correlation information between the true function (i.e., light response function) and measured data in mapping an event characterization vector to the associated position. The CSE method estimates the position where the Chi square error between two functions becomes minimized. In order to determine true statistics as a function of position, the light response function (LRF) was estimated based on sample measurements by using a cubic spline interpolation technique which provides smooth first-order and continuous second-order derivative of the LRF. Both methods have superior linearity properties compared to the weighted centroid. Each method can be considered as a bias-free positioning estimator within the effective field of view of the detector. The spatial resolution performance of the CSE method is similar to7% and similar to 16% better than the weighted centroid method for a 16- and 25-mm-thick crystal, respectively. The spatial resolution performance of the LCC method is comparable to that of the weighted centroid method.

关键词： positioning algorithm scintillation camera

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Wireless Sensor Network Achieved by Automatic positioning System Node

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INTERNATIONAL JOURNAL OF FUTURE GENERATION COMMUNICATION AND NETWORKING 2015年第2期8卷 93-104页

作者： Yang Zhongguo Cai Tianfang Zaozhuang Inst Coll Mech & Elect Engn Tianjin 277160 Peoples R China

In application of wireless sensor network, the position information of sensor node is crucial within life cycle in the whole network. In order to design algorithm of node positioning with high-efficiency, high-precision and low-consumption, this paper puts forward using the encryption algorithm of space control node originally applied in field of engineering measurement, by using SDI algorithm ( space and distance intersection algorithm) as three-dimensional position algorithm used in system to achieve three-dimensional automatic positioning calculation of distributed nodes. Test proves that this kind of algorithm has better positioning nature and higher precision;it is used as three-dimensional positioning because it has good engineering application value.

关键词： Wireless sensor network automatic positioning of node beacon node positioning system positioning algorithm

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