627 research outputs found

    State of the art in digitization of historical maps and analysis of their metric content

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    The present work discuss the digitization and georeferencing of the cartographic heritage preserved in the public archives, with special attention to image quality, support deformation analysis and metric content verification. The use of the photogrammetric techniques is suggested, with some applications to the Sabaudian cadastre

    Evaluation of the results of orthodontic treatment by non-rigid image registration and deformation-based morphometry

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    The goal of this research was to find out, whether the non-rigid registration of dental casts can be used in the evaluation of orthodontic treatment and to develop a program, which would at least partially automatize the evaluation process of images. The aim was also to experiment the evaluation of three-dimensional models of the casts. This research was delimited to cover only the evaluation of malocclusions within the dental arch. The relationships between the dental arches were not considered. This thesis was done in the University of Vaasa at the Department of Electrical Engineering and Energy Technology as a part of the HammasSkanneri research project, whose aim is to automatize the digitization and archiving of dental casts. This research used two-dimensional images of dental casts which were taken of orthodontically treated patients before and after orthodontic treatment. Non-rigid registration was performed by using a registration tool of Fiji software. The evaluation of the accuracy of the registration was performed by measuring distances between manually inserted landmarks, and by comparing the linear and angular parameters of the registered images and the original target images. The displacements of the teeth were approximated with the help of deformation-based morphometry. The accuracy of registration is within reasonable error limits, if the image is taken straight from above of the cast and the registration is performed with the help of landmarks inserted by a human. Estimation of the changes showed that the movement of teeth can be coarsely measured by using deformation-based morphometry based on change estimates that resemble the Jacobian estimates. A set of programs, which partially automatize the evaluation of the accuracy and the changes, were developed. Three-dimensional imaging of the casts was unsuccessful, and thus the development of 3D evaluation system was left as a future research topic.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

    Miniature curved artificial compound eyes.

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    International audienceIn most animal species, vision is mediated by compound eyes, which offer lower resolution than vertebrate single-lens eyes, but significantly larger fields of view with negligible distortion and spherical aberration, as well as high temporal resolution in a tiny package. Compound eyes are ideally suited for fast panoramic motion perception. Engineering a miniature artificial compound eye is challenging because it requires accurate alignment of photoreceptive and optical components on a curved surface. Here, we describe a unique design method for biomimetic compound eyes featuring a panoramic, undistorted field of view in a very thin package. The design consists of three planar layers of separately produced arrays, namely, a microlens array, a neuromorphic photodetector array, and a flexible printed circuit board that are stacked, cut, and curved to produce a mechanically flexible imager. Following this method, we have prototyped and characterized an artificial compound eye bearing a hemispherical field of view with embedded and programmable low-power signal processing, high temporal resolution, and local adaptation to illumination. The prototyped artificial compound eye possesses several characteristics similar to the eye of the fruit fly Drosophila and other arthropod species. This design method opens up additional vistas for a broad range of applications in which wide field motion detection is at a premium, such as collision-free navigation of terrestrial and aerospace vehicles, and for the experimental testing of insect vision theories

    Sensor architectures and technologies for upper limb 3d surface reconstruction: A review

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    3D digital models of the upper limb anatomy represent the starting point for the design process of bespoke devices, such as orthoses and prostheses, which can be modeled on the actual patient’s anatomy by using CAD (Computer Aided Design) tools. The ongoing research on optical scanning methodologies has allowed the development of technologies that allow the surface reconstruction of the upper limb anatomy through procedures characterized by minimum discomfort for the patient. However, the 3D optical scanning of upper limbs is a complex task that requires solving problematic aspects, such as the difficulty of keeping the hand in a stable position and the presence of artefacts due to involuntary movements. Scientific literature, indeed, investigated different approaches in this regard by either integrating commercial devices, to create customized sensor architectures, or by developing innovative 3D acquisition techniques. The present work is aimed at presenting an overview of the state of the art of optical technologies and sensor architectures for the surface acquisition of upper limb anatomies. The review analyzes the working principles at the basis of existing devices and proposes a categorization of the approaches based on handling, pre/post-processing effort, and potentialities in real-time scanning. An in-depth analysis of strengths and weaknesses of the approaches proposed by the research community is also provided to give valuable support in selecting the most appropriate solution for the specific application to be addressed

    Digital Techniques for Documenting and Preserving Cultural Heritage

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    In this unique collection the authors present a wide range of interdisciplinary methods to study, document, and conserve material cultural heritage. The methods used serve as exemplars of best practice with a wide variety of cultural heritage objects having been recorded, examined, and visualised. The objects range in date, scale, materials, and state of preservation and so pose different research questions and challenges for digitization, conservation, and ontological representation of knowledge. Heritage science and specialist digital technologies are presented in a way approachable to non-scientists, while a separate technical section provides details of methods and techniques, alongside examples of notable applications of spatial and spectral documentation of material cultural heritage, with selected literature and identification of future research. This book is an outcome of interdisciplinary research and debates conducted by the participants of the COST Action TD1201, Colour and Space in Cultural Heritage, 2012–16 and is an Open Access publication available under a CC BY-NC-ND licence.https://scholarworks.wmich.edu/mip_arc_cdh/1000/thumbnail.jp

    Adaptive Methods for Robust Document Image Understanding

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    A vast amount of digital document material is continuously being produced as part of major digitization efforts around the world. In this context, generic and efficient automatic solutions for document image understanding represent a stringent necessity. We propose a generic framework for document image understanding systems, usable for practically any document types available in digital form. Following the introduced workflow, we shift our attention to each of the following processing stages in turn: quality assurance, image enhancement, color reduction and binarization, skew and orientation detection, page segmentation and logical layout analysis. We review the state of the art in each area, identify current defficiencies, point out promising directions and give specific guidelines for future investigation. We address some of the identified issues by means of novel algorithmic solutions putting special focus on generality, computational efficiency and the exploitation of all available sources of information. More specifically, we introduce the following original methods: a fully automatic detection of color reference targets in digitized material, accurate foreground extraction from color historical documents, font enhancement for hot metal typesetted prints, a theoretically optimal solution for the document binarization problem from both computational complexity- and threshold selection point of view, a layout-independent skew and orientation detection, a robust and versatile page segmentation method, a semi-automatic front page detection algorithm and a complete framework for article segmentation in periodical publications. The proposed methods are experimentally evaluated on large datasets consisting of real-life heterogeneous document scans. The obtained results show that a document understanding system combining these modules is able to robustly process a wide variety of documents with good overall accuracy

    Digital Techniques for Documenting and Preserving Cultural Heritage

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    This book presents interdisciplinary approaches to the examination and documentation of material cultural heritage, using non-invasive spatial and spectral optical technologies

    X-Fields: Implicit Neural View-, Light- and Time-Image Interpolation

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    We suggest to represent an X-Field -a set of 2D images taken across different view, time or illumination conditions, i.e., video, light field, reflectance fields or combinations thereof-by learning a neural network (NN) to map their view, time or light coordinates to 2D images. Executing this NN at new coordinates results in joint view, time or light interpolation. The key idea to make this workable is a NN that already knows the "basic tricks" of graphics (lighting, 3D projection, occlusion) in a hard-coded and differentiable form. The NN represents the input to that rendering as an implicit map, that for any view, time, or light coordinate and for any pixel can quantify how it will move if view, time or light coordinates change (Jacobian of pixel position with respect to view, time, illumination, etc.). Our X-Field representation is trained for one scene within minutes, leading to a compact set of trainable parameters and hence real-time navigation in view, time and illumination

    Digital workflows for the management of existing structures in the pre- and post-earthquake phases: BIM, CDE, drones, laser-scanning and AI

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    La metodologia BIM, sviluppata in America negli anni '70, ha rivoluzionato l'industria delle costruzioni introducendo i principi di innovazione e digitalizzazione per la gestione dei progetti, in un settore settore produttivo troppo legato a logiche tradizionali. I numerosi processi digitali che sono stati sviluppati da allora hanno riguardato in gran parte la progettazione di nuovi edifici, e sono principalmente legati alla disciplina del construction management. Alcune prime sperimentazioni condotte nel tempo hanno mostrato come l'estensione di questa metodologia agli edifici esistenti comporti molte difficoltà. In questo panorama, il lavoro di tesi si concentra sulla gestione delle strutture nella fase pre e post-sisma con l'obiettivo di sviluppare processi digitali basati sull'uso di tecnologie innovative applicate sia agli edifici ordinari che a quelli storici. Il primo workflow sviluppato, relativo alla fase pre-sisma, è stato denominato scan-to-FEM, ed è finalizzato a particolarizzare il classico processo scan-to-BIM nel campo dell'ingegneria strutturale, analizzando così tutti i passaggi dal rilievo dell'edificio con le tecniche digitali di fotogrammetria e laser-scanning fino all'analisi strutturale e alla valutazione della sicurezza nei confronti delle azioni sismiche. I processi di gestione delle strutture post-sisma sono invece incentrati sulla stima della sicurezza della struttura e sulla definizione delle strategie di intervento, e si basano sull'analisi delle caratteristiche intrinseche della struttura e dei danni indotti dagli eventi sismici. L'intero processo di valutazione del livello operativo di un edificio è stato quindi rivisto alla luce delle moderne tecnologie digitali. Nel dettaglio, sono state sviluppate Reti Neurali Convoluzionali (CNN) per la crack detection, e l'estrazione delle informazioni numeriche associate alle lesioni, gestite poi grazie ai modelli BIM. I quadri fessurativi sono stati digitalizzati grazie allìintroduzione un nuovo oggetto BIM "lesione" (attualmente non codificato nello standard IFC), al quale è stato aggiunto un set di parametri in parte valutati con le CNN ed in parte qualitativi. Durante lo sviluppo di questi processi, sono stati sviluppati nuovi strumenti adhoc per la gestione degli edifici esistenti. In particolare, sono state definite specifiche per lo sviluppo di schede tecniche digitali dei danni, e per la creazione del nuovo oggetto BIM "lesione". I processi di gestione degli edifici danneggiati, grazie agli sviluppi tecnologici realizzati, sono stati applicati per la digitalizzazione dell'edificio storico della chiesa di San Pietro in Vinculis danneggiato a seguito di eventi sismici, grazie ai quali sono stati sperimentati i massimi benefici in termini di riduzione di tempo e risparmio di risorse

    Image Analysis and Machine Learning in Agricultural Research

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    Agricultural research has been a focus for academia and industry to improve human well-being. Given the challenges in water scarcity, global warming, and increased prices of fertilizer, and fossil fuel, improving the efficiency of agricultural research has become even more critical. Data collection by humans presents several challenges including: 1) the subjectiveness and reproducibility when doing the visual evaluation, 2) safety when dealing with high toxicity chemicals or severe weather events, 3) mistakes cannot be avoided, and 4) low efficiency and speed. Image analysis and machine learning are more versatile and advantageous in evaluating different plant characteristics, and this could help with agricultural data collection. In the first chapter, information related to different types of imaging (e.g., RGB, multi/hyperspectral, and thermal imaging) was explored in detail for its advantages in different agriculture applications. The process of image analysis demonstrated how target features were extracted for analysis including shape, edge, texture, and color. After acquiring features information, machine learning can be used to automatically detect or predict features of interest such as disease severity. In the second chapter, case studies of different agricultural applications were demonstrated including: 1) leaf damage symptoms, 2) stress evaluation, 3) plant growth evaluation, 4) stand/insect counting, and 5) evaluation for produce quality. Case studies showed that the use of image analysis is often more advantageous than visual rating. Advantages of image analysis include increased objectivity, speed, and more reproducibly reliable results. In the third chapter, machine learning was explored using romaine lettuce images from RD4AG to automatically grade for bolting and compactness (two of the important parameters for lettuce quality). Although the accuracy is at 68.4 and 66.6% respectively, a much larger data base and many improvements are needed to increase the model accuracy and reliability. With the advancement in cameras, computers with high computing power, and the development of different algorithms, image analysis and machine learning have the potential to replace part of the labor and improve the current data collection procedure in agricultural research. Advisor: Gary L. Hei
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