The thesis addresses the upcoming particle physics programme foreseen at the Beijing Electron Positron Collider II (BEPCII), for which the Beijing Electron Spectrometer III (BESIII) is being upgraded. The work present...
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The thesis addresses the upcoming particle physics programme foreseen at the Beijing Electron Positron Collider II (BEPCII), for which the Beijing Electron Spectrometer III (BESIII) is being upgraded. The work presented focused on the upgrade of the central tracker of the experiment by exploring the possibilities offered by a new approach using CMOS Pixel Sensors (CPS) instead of the present gas drift chamber. The MDC inner chamber of BESIII suffers from ageing effects which lead to performance degrading in terms of detection efficiency, momentum resolu- tion and spatial resolution. From the analysis in 2013, the efficiency of the MDC inner cell could be around 70% and its spatial resolution degraded from ∼ 120µm to ∼ 300µm in the worst case. This ageing effect would prevent BE- SIII from collecting the foreseen data sample and decrease the precision of the measurements. The collaboration decided therefore to upgrade the original in- ner chamber with a newly designed one or with a tracker using more advanced technology. The project of a Silicon Pixel Tracker (SPT) was proposed in this perspective. Two issues in SPT development have been studied: a low material budget of a long ladder and the detecting geometry optimization. CPS prototypes using large pixel pitches and an improved rolling-shutter readout architecture have been tested and studied to validate the sensor performance of a spatial resolution ∼ 10 µm, an integration time ∼ 20.8 µs and a power consumption around 80 mW/cm 2. Therefore, the materials from cooling system are limited to guarantee the low material budget of the ladder. For tracker optimiza- tion, a general method and the related software based on tracking algorithms, numerical geometry scans and Geant4 Monte-Carlo simulations, has been de- veloped and applied for BESIII SPT. The total number (3) of ladders and the tracker layout with a uniform spacing have been determined for the opti- mal momentum measurement for a sensor spatial resolution ∼10
The development of autonomous vehicles requires different sensor types for constructing an accurate local environment model. The evolution of sensor technology is challenging the development of sensor data fusion. Alt...
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ISBN:
(数字)9781728156255
ISBN:
(纸本)9781728156262
The development of autonomous vehicles requires different sensor types for constructing an accurate local environment model. The evolution of sensor technology is challenging the development of sensor data fusion. Although, the sensors are getting more robust and reliable. However, because of the development of sensors the data fusion should be able to handle diversified sensor clusters. Thus, the high-level sensor fusion algorithms, like track to track method, are getting more important. This paper introduces different tracking approaches, which are intended to support a track-to-track fusion method of an autonomous vehicle in highway situations.
The use of protons to treat cancer has expanded rapidly in the past two decades. For safe and e↵ective proton therapy, the proton range in a patient's body must be accu- rately determined. Current treatment planni...
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The use of protons to treat cancer has expanded rapidly in the past two decades. For safe and e↵ective proton therapy, the proton range in a patient's body must be accu- rately determined. Current treatment planning is based on X-ray computed tomogra- phy images, which might cause uncertainty because of the di↵erent behaviour between protons and X-rays. As an alternative, proton Computed Tomography (pCT) has been proposed to directly measure the Relative Stopping Power (RSP) map in the patient and reduce this uncertainty. During a proton CT scan, a high-energy proton beam is directed at the patient. Then, the proton's residual energy and position are measured with a detector placed behind the patient. This information is used to calculate the volumetric RSP. In the case of using a pixel based detector, a tracking algorithm is required in order to increase the proton intensity capacity of the detec- tor. A proton track reconstruction system has been already developed by Pettersen [1], however, it has some limitations on the track density that can be reconstructed correctly. The algorithm is based on the track-following scheme, in which a growing track searches for deeper- laying activated pixels. This thesis introduces proton therapy and the advantages of pCT and proton ra- diography for treatment planning. Then, the main track reconstruction techniques found in the literature are reviewed. Improvements in the reconstruction process are proposed and their e? ciencies are discussed. While current algorithm begins from the layer closest to the patient, in the present study a new reconstruction algorithm is developed. It di↵ers by starting the reconstruction process from the distal end of the detector. Based on this new algorithm, studies related to its optimization are conducted. Lastly, an algorithm based on the identification of the most probable scenario is developed. The potential algorithms are evaluated on data simulated with GATE (based on Monte Carlo interactio
Aiming at the solar photovoltaic characteristics and the lower transformation efficiency problem in grid-connected photovoltaic power generation, a maximum power point tracking(MPPT) algorithm is put forward. Accordin...
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ISBN:
(纸本)9781510803084
Aiming at the solar photovoltaic characteristics and the lower transformation efficiency problem in grid-connected photovoltaic power generation, a maximum power point tracking(MPPT) algorithm is put forward. According to the changes of amplitude and frequency of power-grid voltage, the proposed algorithm can calculate the correction value of maximum power point, which will be stacked with the maximum power obtained by means of perturbation and observation method, and then the MPPT control is realized. Simulation experiment results present that, compared with the traditional MPPT method using perturbation observation, the proposed method can avoid misjudgment, guarantee the shorter time for maximum power point tracking, and reduce the shock around the maximum power point. Moreover, it can effectively suppress the influences of instable factors on the maximum power point, and meet the optimal power point for stable operation of power grid.
Omnidirectional vision(Omni-vision)has the feature that an extremely wide view can be achieved simultaneously. The omni-image brings a highly unavoidable inherent distortion while it provides hemispherical field of **...
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Omnidirectional vision(Omni-vision)has the feature that an extremely wide view can be achieved simultaneously. The omni-image brings a highly unavoidable inherent distortion while it provides hemispherical field of *** this paper,a method called Spherical Perspective Projection is used for correction of such distorted ***-vision target recognition and tracking with fisheye lens for AGVs appears definite significant since its advantage of acquiring all vision information of the three-dimensional space once.A novel Beacon Model and Omni-vision tracker for mobile robots is *** present,the research of target model has many different problems,such as outdoor illumination, target veiling,target ***,outdoor illumination and beacon veiling are the key problems which need an effective method to *** new beacon model which features particular topology shape can be recognized in the outdoors with part veiled of the *** this paper an improved omni-vision object tracking method based on mean shift algorithm is *** mean shift algorithm which is a powerful technique for tracking objects in image sequences with complex background has been proved to be successful for the fast computation and effective tracking *** recognition and tracking functions have been demonstrated on experimental platform.
This project details the design and implementation of an offline data processor for a radar system in order to track targets that have been detected. It associates the detections in tracks that belong to the targets i...
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This project details the design and implementation of an offline data processor for a radar system in order to track targets that have been detected. It associates the detections in tracks that belong to the targets in the scene. Additionally a script to simulate targets has been implemented and used to train and test the tracker developed. This tracker is developed for a ubiquitous radar demonstrator (RAD-DAR), which is in its field test stage. The demonstrator has been designed and developed by the Microwave and Radar Research Group (GMR), taking over all the stages of hardware and software design. The radar system consists of a frequency modulated continuous waveform (FMCW) ubiquitous radar that works at X-Band (8.75 GHz). The results of the first stages have already been presented in several national and international conferences for the last two years [1], [2]. The radar demonstrator uses one transmitting antenna and eight receiving antennas in order to cover the whole are to survey. Afterwards, in the post-processing of the recorded scene, beamforming and monopulse techniques are performed in order to point the beam of the receiver towards the area of interest. Also a 2D-FFT processing is carried out to obtain the information of range and speed of the targets. algorithm has been tested on data from simulated scenarios and field-test scenarios. The field tests consist in scenes with a commercial drone in controlled flights and a scen with vehicles in a highway 2.5 km away from the rad. The tests obtained show positive results because in the scene with cars it is able to separate the cars into tracks (probed at plain sight, since GPS data was not available), additionally have been compared in the case of the drone to real GPS data of the target. The first stage of this project included the familiarization with the developed radar demonstrator and with the format of the data obtained from the demonstrator. Additionally, this initial stage implied the search of bi
This paper introduces a real-time TV tracking system which is based on DSP(DM642). It narrates the principle of hardware design and the structure of the hardware in detail. A fast median filter algorithm, which is the...
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ISBN:
(纸本)9781424447749
This paper introduces a real-time TV tracking system which is based on DSP(DM642). It narrates the principle of hardware design and the structure of the hardware in detail. A fast median filter algorithm, which is the most novelty in the system, is used to achieve the image pre-processed. And the algorithm of centroid calculated and Gaussian-fitting predicting approach are used to track the target. The experiment proves that this system can obtain continuous and stable tracking effect when the target is moving and covered up.
Předmětem této diplomové práce bylo vybrat a implementovat metody určené pro detekci a sledování osob v komerčních aplikacích. Výsledné řešení bylo voleno jako k...
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Předmětem této diplomové práce bylo vybrat a implementovat metody určené pro detekci a sledování osob v komerčních aplikacích. Výsledné řešení bylo voleno jako kombinace moderních přístupů a metod, s kterými přišel výzkum a vývoj poslední doby. Algoritmus je schopen vytvářet trajektorie pohybu osob ve vnitřních prostorách budov, a to i v případě částečného nebo úplného zakrytí sledovaných objektů. Scéna je snímána statickou kamerou umožňující přímý pohled na sledované osoby. Vybrané metody jsou implementovány v programovém jazyce C# s využitím funkcí knihovny OpenCV. Výstup algoritmu je zobrazován ve vytvořeném uživatelském rozhraní.
Bakalárska práca bola zameraná na evaluáciu sledovacích algoritmov, obsiahnutých v knižnici OpenCV voči motion blur efektu. Bol vytvorený dataset videí s definovanými rozsa...
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Bakalárska práca bola zameraná na evaluáciu sledovacích algoritmov, obsiahnutých v knižnici OpenCV voči motion blur efektu. Bol vytvorený dataset videí s definovanými rozsahmi vybraných parametrov, ktoré ovplyvňovali vznik motion blur efektu (rýchlosť, vzdialenosť od objektu, pozícia svetla a ďalšie). Každé z videí bolo spracované pomocou sledovacieho algoritmu. Z týchto výsledkov boli v závere formulované zistenia o efektivite každého z algoritmov pre definovanú situáciu.
This paper presents a data processing algorithm with machine learning for polarization extraction and event selection applied to photoelectron track images taken with X-ray polarimeters. The method uses a convolutiona...
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This paper presents a data processing algorithm with machine learning for polarization extraction and event selection applied to photoelectron track images taken with X-ray polarimeters. The method uses a convolutional neural network (CNN) classification to predict the azimuthal angle and 2-D position of the initial photoelectron emission from a 2-D track image projected along the X-ray incident direction. Two CNN models are demonstrated with data sets generated by a Monte Carlo simulation: one has a commonly used loss function calculated by the cross entropy and the other has an additional loss term to penalize nonuniformity for an unpolarized modulation curve based on the H-test, which is used for periodic signal search in X-ray/gamma-ray astronomy. The modulation curve calculated by the former model with unpolarized data has several irregular features, which can be canceled out by unfolding the angular response or simulating the detector rotation. On the other hand, the latter model can predict a flat modulation curve with a residual systematic modulation down to less than or similar to 1%. Both models show almost the same modulation factors and position accuracy of less than 2 pixel (or 240 mu m) for all four test energies of 2.7, 4.5, 6.4, and 8.0 keV. In addition, event selection is performed based on probabilities from the CNN to maximize the polarization sensitivity considering a trade-off between the modulation factor and signal acceptance. The developed method with machine learning improves the polarization sensitivity by 10%-20%, compared to that determined with the image moment method developed previously.
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