77 research outputs found

    A high dynamic Micro Strips Ionization Chamber featuring Embedded Multi DSP Processing

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    An X-ray detector will be presented that is the combination of a segmented ionization chamber featuring one-dimensional spatial resolution integrated with an intelligent ADC front-end, multi DSP processing and embedded PC platform. This detector is optimized to fan beam geometry with an active area of 192 mm (horizontal) and a vertical acceptance of 6 mm. Spatial resolution is obtained by subdividing the anode into readout strips, having pitch of 150 micrometers, which are connected to 20 custom made integrating VLSI chips (each capable of 64-channel read-out and multiplexing) and read out by 14 bits 10 MHz ADCs and fast adaptive PGAs into DSP boards. A bandwidth reaching 3.2Gbit/s of raw data, generated from the real time sampling of the 1280 micro strips, is cascaded processed with FPGA and DSP to allow data compression resulting in several days of uninterrupted acquisition capability. Fast acquisition rates reaching 10 kHz are allowed due to the MicroCAT structure utilized not only as a shielding grid in ionization chamber mode but also to provide active electron amplification in the gas.Comment: 5 pages, 7 figures, distilled by AFPL Ghostscript 7.0

    A 3-year follow-up study on bone structure elastic quality

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    Osteoporosis is called a silent disease because bone fragility manifests itself to the patient only in an advanced state, through fracture and pain. Medical and industry leaders recognize that the current golden standard diagnostic method, densitometry, or Dual Energy X-ray Absorptiometry (DEXA), may not always be sufficient to assess the patient’s real risk of fragility fracture [1]. Indeed, pathological alterations affect not only the mineral content (quantity) of the bone, but also its “quality”, which can be measured from the elastic properties of the bone internal trabecular structure by means of the Bone Elastic Structure Test, BES TEST®. In this study, the incidence of fragility fractures was assessed after a 3-year follow-up period in the women enrolled for a population study in 2015. The BES TEST® resulted an effective estimator of bone health, and can improve the assessment of the patient’s fracture risk map

    Does Deep Learning-Based Super-Resolution Help Humans With Face Recognition?

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    The last decade witnessed a renaissance of machine learning for image processing. Super-resolution (SR) is one of the areas where deep learning techniques have achieved impressive results, with a speci fi c focus on the SR of facial images. Examining and comparing facial images is one of the critical activities in forensic video analysis; a compelling question is thus whether recent SR techniques could help face recognition (FR) made by a human operator, especially in the challenging scenario where very low resolution images are available, which is typical of surveillance recordings. This paper addresses such a question through a simple yet insightful experiment: we used two state- of-the-art deep learning-based SR algorithms to enhance some very low-resolution faces of 30 worldwide celebrities. We then asked a heterogeneous group of more than 130 individuals to recognize them and compared the recognition accuracy against the one achieved by presenting a simple bicubic-interpolated version of the same faces. Results are somehow surprising: despite an undisputed general superiority of SR-enhanced images in terms of visual appearance, SR techniques brought no considerable advantage in overall recognition accuracy

    Video Enhancement and Dynamic Range Control of HDR Sequences for Automotive Applications

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    CMOS video cameras with high dynamic range (HDR) output are particularly suitable for driving assistance applications, where lighting conditions can strongly vary, going from direct sunlight to dark areas in tunnels. However, common visualization devices can only handle a low dynamic range, and thus a dynamic range reduction is needed. Many algorithms have been proposed in the literature to reduce the dynamic range of still pictures. Anyway, extending the available methods to video is not straightforward, due to the peculiar nature of video data. We propose an algorithm for both reducing the dynamic range of video sequences and enhancing its appearance, thus improving visual quality and reducing temporal artifacts. We also provide an optimized version of our algorithm for a viable hardware implementation on an FPGA. The feasibility of this implementation is demonstrated by means of a case study

    Rotura de un aneurisma de arteria esplénica. A proposito de un caso y revisión de la literatura

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    La prevalencia de aneurismas esplénicos en la población general es del 0,8%, siendo más alta en mujeres que en hombres. El embarazo, la fibrodis plasia arterial y la hipertensión portal, con o sin esplenomegalia asociada, son factores de riesgo conocidos asociados al desarrollo de aneurismas esplénicos. Se presenta el caso clínico de una pa ciente nulípara de 24 años, sin factores de riesgo vasculares y con antecedentes de paludismo, que acudió al servicio de urgencias de nuestro centro por presentar dolor abdominal tras un vuelo en avión de larga distancia. La exploración física y las pruebas complementarias realizadas mostraron un shock hipovolémico por hemoperitoneo. A pe sar del tratamiento de apoyo, la paciente falleció antes de su entrada en quirófano. La necropsia mostró la rotura de un aneurisma sacular de la arteria esplénica como causa de muerte. Se discu te la posibilidad de que un barotrauma pueda ha ber sido la causa de rotura aneurismáti

    Multichannel Time Synchronization Based on PTP through a High Voltage Isolation Buffer Network Interface for Thick-GEM Detectors

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    Data logging and complex algorithm implementations acting on multichannel systems with independent devices require the use of time synchronization. In the case of Gas Electron Multipliers (GEM) and Thick-GEM (THGEM) detectors, the biasing potential can be generated at the detector level via DC to DC converters operating at floating voltage. In this case, high voltage isolation buffers may be used to allow communication between the different channels. However, their use add non-negligible delays in the transmission channel, complicating the synchronization. Implementation of a simplified precise time protocol is presented for handling the synchronization on the Field Programmable Gate Array (FPGA) side of a Xilinx SoC Zynq ZC7Z030. The synchronization is done through a high voltage isolated bidirectional network interface built on a custom board attached to a commercial CIAA_ACC carrier. The results of the synchronization are shown through oscilloscope captures measuring the time drift over long periods of time, achieving synchronization in the order of nanoseconds

    A modular software framework for the design and implementation of ptychography algorithms

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    Computational methods are driving high impact microscopy techniques such as ptychography. However, the design and implementation of new algorithms is often a laborious process, as many parts of the code are written in close-to-the-hardware programming constructs to speed up the reconstruction. In this article, we present SciComPty, a new ptychography software framework aiming at simulating ptychography datasets and testing state-of-the-art and new reconstruction algorithms. Despite its simplicity, the software leverages GPU accelerated processing through the PyTorch CUDA interface. This is essential for designing new methods that can readily be employed. As an example, we present an improved position refinement method based on Adam and a new version of the rPIE algorithm, adapted for partial coherence setups. Results are shown on both synthetic and real datasets. The software is released as open-source

    Unusual focal keratin expression in plexiform angiomyxoid myofibroblastic tumor: A case report and review of the literature

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    Background: Plexiform angiomyxoid myofibroblastic tumor (PAMT), also known as plexiform fibromyxoma, is a rare distinctive benign intramural tumor, typical of gastric antrum, commonly causing mucosal ulceration with upper gastrointestinal bleeding and anemia, effectively treated by complete surgical resection usually accomplished by distal gastrectomy. Methods and Results: We herein report a 47-year-old man presenting with a syncopal episode, regurgitation and epigastric discomfort, bearing a gastric antral myxoid plexiform tumor positive for \u3b1-smooth muscle actin, vimentin and, partially, for caldesmon, desmin, and CD10; CD117, DOG1, CD34, S100, CAM5.2, CK20, CK7, EMA, p53, CDX2, chromogranin A, synaptophysin, anaplastic lymphoma kinase, Melan-A, and HMB-45 were all negative. All these features are typical of PAMT. Of note, focal positivity for AE1/AE3 and pan-CK KL1 was also present. Conclusions: The finding of a focal keratin expression in PAMT contributes to enlarge the immunophenotypic spectrum of this tumor type and is relevant for avoiding presurgical misdiagnoses which could ultimately lead to inappropriate overtreatment of patients with PAMT

    First results of a novel Silicon Drift Detector array designed for low energy X-ray fluorescence spectroscopy

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    We developed a trapezoidal shaped matrix with 8 cells of Silicon Drift Detectors (SDD) featuring a very low leakage current (below 180 pA/cm2 at 20 \ub0C) and a shallow uniformly implanted p+ entrance window that enables sensitivity down to few hundreds of eV. The matrix consists of a completely depleted volume of silicon wafer subdivided into 4 square cells and 4 half-size triangular cells. The energy resolution of a single square cell, readout by the ultra-low noise SIRIO charge sensitive preamplifier, is 158 eV FWHM at 5.9 keV and 0 \ub0C. The total sensitive area of the matrix is 231 mm2 and the wafer thickness is 450\u3bcm. The detector was developed in the frame of the INFN R&D project ReDSoX in collaboration with FBK, Trento. Its trapezoidal shape was chosen in order to optimize the detection geometry for the experimental requirements of low energy X-ray fluorescence (LEXRF) spectroscopy, aiming at achieving a large detection angle. We plan to exploit the complete detector at the TwinMic spectromicroscopy beamline at the Elettra Synchrotron (Trieste, Italy). The complete system, composed of 4 matrices, increases the solid angle coverage of the isotropic photoemission hemisphere about 4 times over the present detector configuration. We report on the layout of the SDD matrix and of the experimental set-up, as well as the spectroscopic performance measured both in the laboratory and at the experimental beamline. \ua9 2015 Elsevier B.V

    Temporal video segmentation: A survey

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    Temporal video segmentation is the "rst step towards automatic annotation of digital video for browsing and retrieval. This article gives an overview of existing techniques for video segmentation that operate on both uncompressed and compressed video stream. The performance, relative merits and limitations of each of the approaches are comprehensively discussed and contrasted. The gradual development of the techniques and how the uncompressed domain methods were tailored and applied into compressed domain are considered. In addition to the algorithms for shot boundaries detection, the related topic of camera operation recognition is also reviewed. � 2001 Elsevier Science B.V. All rights reserved
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