18,624 research outputs found

    Metrological Characterization of a Vision-Based Measurement System for the Online Inspection of Automotive Rubber Profile

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    This paper deals with the metrological characterization of a stereovision-based measurement system for the inspection of automotive rubber profiles in an industrial plant. The characterization of this class of measurement systems introduces new challenges due to both the unavailability of reference measurement instruments and the complexity of the measurement system itself, which does not allow a straightforward application of the standard procedures for uncertainty evaluation. To assign optimum values to a number of design parameters, the followed approach focuses not only on evaluating the total uncertainty but also on analyzing systematic effects and influence quantities

    Digital image correlation techniques applied to LANDSAT multispectral imagery

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    The author has identified the following significant results. Automatic image registration and resampling techniques applied to LANDSAT data achieved accuracies, resulting in mean radial displacement errors of less than 0.2 pixel. The process method utilized recursive computational techniques and line-by-line updating on the basis of feedback error signals. Goodness of local feature matching was evaluated through the implementation of a correlation algorithm. An automatic restart allowed the system to derive control point coordinates over a portion of the image and to restart the process, utilizing this new control point information as initial estimates

    CCD imaging instruments for planetary spacecraft applications

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    The development of new spacecraft camera systems to be used in conjunction with CCD sensors is reported. A brief overview of the science objectives and engineering constraints which influence the design of cameras for deep space is followed by a review of two current development programs, one leading to a line scan imager and the other to an area array frame camera. For each of these, a general description of the imager is given. It is evident that currently available CCDs fall short of requirements in some respects

    Real-time virtual sonography in gynecology & obstetrics. literature's analysis and case series

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    Fusion Imaging is a latest generation diagnostic technique, designed to combine ultrasonography with a second-tier technique such as magnetic resonance imaging and computer tomography. It has been mainly used until now in urology and hepatology. Concerning gynecology and obstetrics, the studies mostly focus on the diagnosis of prenatal disease, benign pathology and cervical cancer. We provided a systematic review of the literature with the latest publications regarding the role of Fusion technology in gynecological and obstetrics fields and we also described a case series of six emblematic patients enrolled from Gynecology Department of Sant ‘Andrea Hospital, “la Sapienza”, Rome, evaluated with Esaote Virtual Navigator equipment. We consider that Fusion Imaging could add values at the diagnosis of various gynecological and obstetrics conditions, but further studies are needed to better define and improve the role of this fascinating diagnostic tool

    Morphometric Analysis through 3D Modelling of Bronze Age Stone Moulds from Central Sardinia

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    Stone moulds were basic elements of metallurgy during the Bronze Age, and their analysis and characterization are very important to improve the knowledge on these artefacts useful for typological characterization. The stone moulds investigated in this study were found during an archaeological field survey in several Nuragic (Bronze Age) settlements in Central Sardinia. Recent studies have shown that photogrammetry can be effectively used for the 3D reconstruction of small and medium‐sized archaeological finds, although there are still many challenges in producing high‐quality digital replicas of ancient artefacts due to their surface complexity and consistency. In this paper, we propose a multidisciplinary approach using mineralogical (X‐ray powder diffraction) and petrographic (thin section) analysis of stone materials, as well as an experimental photogrammetric method for 3D reconstruction from multi‐view images performed with recent software based on the CMPMVS algorithm. The photogrammetric image dataset was carried out using an experimental rig equipped with a 26.2 Mpix full frame digital camera. We also assessed the accuracy of the reconstruction models in order to verify their precision and readability according to archaeological goals. This allowed us to provide an effective tool for more detailed study of the geometric‐dimensional aspects of the moulds. Furthermore, this paper demonstrates the potentialities of an integrated minero‐petrographic and photogrammetric approach for the characterization of small artefacts, providing an effective tool for more in‐depth investigation of future typo-logical comparisons and provenance studies

    Indirect Image Registration with Large Diffeomorphic Deformations

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    The paper adapts the large deformation diffeomorphic metric mapping framework for image registration to the indirect setting where a template is registered against a target that is given through indirect noisy observations. The registration uses diffeomorphisms that transform the template through a (group) action. These diffeomorphisms are generated by solving a flow equation that is defined by a velocity field with certain regularity. The theoretical analysis includes a proof that indirect image registration has solutions (existence) that are stable and that converge as the data error tends so zero, so it becomes a well-defined regularization method. The paper concludes with examples of indirect image registration in 2D tomography with very sparse and/or highly noisy data.Comment: 43 pages, 4 figures, 1 table; revise
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