- 标题
- 摘要
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- 实验方案
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Study of Power Consumption of Timepix3 Detector
摘要： The Timepix3 readout chip — the latest member of the Medipix family of hybrid pixel detectors — brought several new functionalities in comparison with the older Timepix, i.e. a high hit-rate, a time granularity of 1.5625 ns, a data-driven readout scheme (with a per pixel dead time of approximately 475 ns), and the capability of measuring Time-over-Threshold (ToT) and Time-of-Arrival (ToA) in each pixel at the same time. However, the high power consumption of the Timepix3 in the standard setting prevents its use in applications with limited power budget. Moreover, the high power consumption poses the risk of overheating the sensor so that proper cooling is crucial. The presented work investigates the effect of different settings in the analogue and a digital part of the Timepix3 detector on its power consumption. Measurements were performed with the Timepix3 chipboard. The firmware of the Katherine readout was modified so that the user can monitor the power consumptions of analogue and digital part “on-line” (directly in the control software). In standard settings, a power consumption of approximately 1.3 W was found. By changes of internal DACs, the consumption could be reduced to 650 mW. Further reduction was achieved by the change of the clock management in the digital part of the Timepix3. In result, a power consumption of 216 mA could be achieved. In these low power settings, the ToA clock was reduced to 10 MHz and thus the time binning was 100 ns. The energy resolution was not affected significantly. The pixel dead time is also negatively affected when the matrix clock is reduced. In the case of 10 MHz, the minimal per pixel dead time is 1.9 μs.
关键词： databases),Detector control systems (detector and experiment monitoring and slow-control systems,Data acquisition concepts,hardware,algorithms,architecture
更新于2025-09-23 15:23:52
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Enhanced depth estimation of integral imaging using pixel blink rate
摘要： In this paper, we propose a new depth estimation technique with enhanced depth resolution in three-dimensional (3D) integral imaging. Typical integral imaging using a lenslet array can obtain elemental images with different perspectives by a single shot. However, the lateral and depth resolutions of the reconstructed 3D image may be low, which limit applications of integral imaging such as for object tracking, occlusion removal, and depth estimation. Especially, enhanced depth estimation may be required since depth is the most important information for all 3D applications. In this paper, we use the pixel rearrangement technique for visual quality enhancement of the reconstructed 3D image, and use pixel blink rate to evaluate the defocus area for depth estimation improvement. Our experimental results support that our method can enhance the depth resolution in typical integral imaging using lenslet arrays.
关键词： Depth estimation,Three-dimensional image acquisition,Three-dimensional image processing
更新于2025-09-23 15:23:52
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Simultaneous acquisition of polarimetric SVBRDF and normals
摘要： Capturing appearance often requires dense sampling in light-view space, which is often achieved in specialized, expensive hardware setups. With the aim of realizing a compact acquisition setup without multiple angular samples of light and view, we sought to leverage an alternative optical property of light, polarization. To this end, we capture a set of polarimetric images with linear polarizers in front of a single projector and camera to obtain the appearance and normals of real-world objects. We encountered two technical challenges: First, no complete polarimetric BRDF model is available for modeling mixed polarization of both specular and diffuse reflection. Second, existing polarization-based inverse rendering methods are not applicable to a single local illumination setup since they are formulated with the assumption of spherical illumination. To this end, we first present a complete polarimetric BRDF (pBRDF) model that can define mixed polarization of both specular and diffuse reflection. Second, by leveraging our pBRDF model, we propose a novel inverse-rendering method with joint optimization of pBRDF and normals to capture spatially-varying material appearance: per-material specular properties (including the refractive index, specular roughness and specular coefficient), per-pixel diffuse albedo and normals. Our method can solve the severely ill-posed inverse-rendering problem by carefully accounting for the physical relationship between polarimetric appearance and geometric properties. We demonstrate how our method overcomes limited sampling in light-view space for inverse rendering by means of polarization.
关键词： polarization,SVBRDF acquisition
更新于2025-09-23 15:23:52
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Occasion determination method of low Earth orbit satellites meeting the narrow-beam signal
摘要： The determination of the occasion when the low Earth orbit satellite meets the narrow-beam signal is quite important. Based on the orbit prediction model of simplified general perturbations 4 (SGP4), the calculation model of the relative position between the low Earth orbit satellite and the ground target is established in the paper, and so is the calculation model of the relative position between the low Earth orbit satellite and the high Earth orbit communication satellite. The determination method of the occasion when the low Earth orbit satellite meets the narrow-beam signal is further proposed. It is shown by the simulation results that the proposed calculation method possesses high accuracy and feasibility and is able to satisfy the practical application requirements.
关键词： signal monitoring,SGP4,uplink signal acquisition,communication signal acquisition,payloads boot time,Satellite orbit prediction
更新于2025-09-23 15:22:29
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Development of the readout system for a time projection chamber prototype
摘要： A new GEM-TPC prototype with a laser calibration system is being designed to study the key issues of high-precision track detection whose aimed spatial resolution is better than 100 μm. Meanwhile, a readout system with scalability for the TPC is also being developed. Design of the readout system is based on the architecture of front-end ASICs and commercial ADCs for its advantages at high count rates. Given the requirement of several hundred channels, the system is composed of multiple front-end cards and DAQ boards. The DAQ boards are daisy-chained via bidirectional optical fibers, which transmit clock, trigger, data and control signals simultaneously. To achieve timing synchronization, the GigaBit Transceiver (GBT) firmware is employed to ensure fixed latency between the boards. This paper is focused on the design and setup of the DAQ system, including clock structure, trigger alignment, high-speed data acquisition, etc. The DAQ system consisting of 512 channels has been built, and tests have proved that the entire system works correctly and meets the expected requirements.
关键词： Trigger concepts and systems (hardware and software),Electronic detector readout concepts (gas, liquid),Modular electronics,Data acquisition concepts
更新于2025-09-23 15:22:29
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A multipurpose X-ray fluorescence scanner developed for in situ analysis
摘要： Over the time, instrument transportability has become more and more important, especially in Cultural Heritage, as often artworks cannot be moved from their site, either because of the size or due to problems with permission issues, or simply because moving them to a laboratory is physically impossible, as e.g. in the case of mural paintings. For this reason, the INFN-CHNet, the network for Cultural Heritage studies of the Italian National Institute of Nuclear Physics (INFN), has developed an XRF scanner for in situ analyses. The instrument is the result of a wide collaboration, where different units of the network have been developing the diverse parts, then merged in a single system. The XRF scanner has been designed to be a four-season and green instrument. The control/acquisition/analysis software has been fully developed by our group, using only open-source software. Other strong points of the system are easiness of use, high portability, good performances and ultra-low radiation dispersion, which allows us to use even when the public can be present. It can run both with mains or on batteries, in the latter case with a maximum runtime longer than 10 h. It has a very low cost, when compared to commercial systems with equivalent performances, and easily replaceable components, which makes it accessible for a much wider portion of the interested community. The system has been thought and designed as an open system, suitable for further development/improvements, that can result interesting for non-conventional XRF analysis. The CHNet XRF scanner has proved to be really very well suited for applications in the Cultural Heritage field, as testified by the many recent applications. This paper describes the present version of our instrument and reports on the tests performed to characterise its main features.
关键词： Transportable instrument,XRF imaging,Acquisition,In situ analysis,Cultural heritage,XRF scanner
更新于2025-09-23 15:22:29
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[IEEE 2018 Asia Communications and Photonics Conference (ACP) - Hangzhou, China (2018.10.26-2018.10.29)] 2018 Asia Communications and Photonics Conference (ACP) - Loop Parameters Designing Method for Optical Phase-Locked Loop System
摘要： A comprehensive loop parameters designing method and an auxiliary pulling module for an optical phase-locked system were discussed. The experiment successfully demonstrated a pull-in frequency range as wide as 2.4GHz and a frequency accuracy of 2MHz.
关键词： optical phase-locked,auxiliary pulling module,noise performance,acquisition,loop parameters,tracking
更新于2025-09-23 15:22:29
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[American Society of Agricultural and Biological Engineers 2017 Spokane, Washington July 16 - July 19, 2017 - ()] 2017 Spokane, Washington July 16 - July 19, 2017 - LabVIEW base software for spatial frequency domain imaging system
摘要： Spatial frequency domain imaging, a novel non-contact optical imaging technology, can quantitatively detect optical properties of agro-products which are connected with chemical components and physical structure of tissue. This study introduced a custom program written in LabVIEW 2014 to simplify the configuration and operation of spatial frequency domain imaging system. The LabVIEW procedure can realize several functions: generating sinusoidal grayscale patterns which were projected onto the surface of phantom through a digital projector, controlling motorized precision translation stage to change the position of sample accurately, triggering the CCD camera to circularly collect images, and doing data processing to extract optical properties of tissue. We detected the absorption coefficient and reduced scattering coefficient of a series of self-made solid phantoms with known optical properties and a Fuji red apple using the system proposed in study. The results of phantoms experiment were compared with that detected by the former procedure which processes data in MATLAB. The detection time is reduced, and few difference in accuracy was obtained which means the new software is practicable in spatial frequency domain imaging system. The result of apple experiment demonstrated this system can realize the correct detection of optical properties of apple.
关键词： LabVIEW,Optical properties,Imaging acquisition,Apple,SFDI
更新于2025-09-23 15:22:29
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Comparison of basis functions and q-space sampling schemes for robust compressed sensing reconstruction accelerating diffusion spectrum imaging
摘要： Time constraints placed on magnetic resonance imaging often restrict the application of advanced diffusion MRI (dMRI) protocols in clinical practice and in high throughput research studies. Therefore, acquisition strategies for accelerated dMRI have been investigated to allow for the collection of versatile and high quality imaging data, even if stringent scan time limits are imposed. Diffusion spectrum imaging (DSI), an advanced acquisition strategy that allows for a high resolution of intra-voxel microstructure, can be sufficiently accelerated by means of compressed sensing (CS) theory. CS theory describes a framework for the efficient collection of fewer samples of a data set than conventionally required followed by robust reconstruction to recover the full data set from sparse measurements. For an accurate recovery of DSI data, a suitable acquisition scheme for sparse q-space sampling and the sensing and sparsifying bases for CS reconstruction need to be selected. In this work we explore three different types of q-space undersampling schemes and two frameworks for CS reconstruction based on either Fourier or SHORE basis functions. After CS recovery, diffusion and microstructural parameters and orientational information are estimated from the reconstructed data by means of state-of-the-art processing techniques for dMRI analysis. By means of simulation, diffusion phantom and in vivo DSI data, an isotropic distribution of q-space samples was found to be optimal for sparse DSI. The CS reconstruction results indicate superior performance of Fourier-based CS-DSI compared to the SHORE-based approach. Based on these findings we outline an experimental design for accelerated DSI and robust CS reconstruction of the sparse measurements that is suitable for the application within time-limited studies.
关键词： diffusion MRI,sparse acquisition,q-space undersampling,microstructure,compressed sensing,basis functions,diffusion spectrum imaging
更新于2025-09-23 15:22:29
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Quantum States of Heralded Photons
摘要： In this paper, the design and the development of a remote system for continuous monitoring of leakage currents and ground currents in high voltage electrical substations are proposed. Based on wireless local area network technology, the system can be used to monitor continuously a variety of plants within the substation and has low power consumption with inbuilt overvoltage protection. It consists of a transmitter module equipped with a data acquisition (DAQ) system connected to leakage current and voltage sensors, and a receiver module connected to a remote controller for data processing and storage. The principle of operation and the characteristics of the various components of the system are described. Validation tests have been used to verify its performance in three different test situations: A) laboratory monitoring of the leakage current and voltage of a distribution surge arrester; B) laboratory measurement of the leakage current of an outdoor insulator; and C) ?eld monitoring of the earth current and potential rise of high-voltage tower. The measured results are in close agreement with those recorded directly through a DAQ card with ?ber-optic and coaxial cable connected systems. Data processing is carried out at the receiving end so that the monitored parameter is displayed continuously or at speci?ed time intervals. The operation of the system has been tested and proved resilient under high-frequency interference signals such as those generated by corona and surface discharges.
关键词： wireless transmission,solar power,surge arrester,data acquisition,high-voltage substation,leakage current measurement,insulator,WLAN system,Continuous monitoring
更新于2025-09-23 15:21:01