Colour analysis of degraded parchment

Multispectral imaging was employed to collect data on the degradation of an 18th century parchment by a series of physical and chemical treatments. Each sample was photographed before and after treatment by a monochrome digital camera with 21 narrow-band filters. A template-matching technique was used to detect the circular holes in each sample and a four-point projective transform to register the 21 images. Colour accuracy was verified by comparison of reconstructed spectra with measurements by spectrophotometer

Progressive Refinement Imaging

This paper presents a novel technique for progressive online integration of uncalibrated image sequences with substantial geometric and/or photometric discrepancies into a single, geometrically and photometrically consistent image. Our approach can handle large sets of images, acquired from a nearly planar or infinitely distant scene at different resolutions in object domain and under variable local or global illumination conditions. It allows for efficient user guidance as its progressive nature provides a valid and consistent reconstruction at any moment during the online refinement process. // Our approach avoids global optimization techniques, as commonly used in the field of image refinement, and progressively incorporates new imagery into a dynamically extendable and memory‐efficient Laplacian pyramid. Our image registration process includes a coarse homography and a local refinement stage using optical flow. Photometric consistency is achieved by retaining the photometric intensities given in a reference image, while it is being refined. Globally blurred imagery and local geometric inconsistencies due to, e.g. motion are detected and removed prior to image fusion. // We demonstrate the quality and robustness of our approach using several image and video sequences, including handheld acquisition with mobile phones and zooming sequences with consumer cameras

High Speed Vision Based Automatic Inspection and Path Planning for Processing Conveyed Objects

AbstractUnder the pressure of cost reduction and productivity improvement, this paper presents a new methodology which provides a fast inspection of defective objects and generates a real time motion trajectory for processing objects being conveyed with high speed in an industrial large-scale production. The image data obtained by a multispectral imaging system is analyzed within image processing algorithms using classification methods based on support vector machine. These data provide a basis for a path planning algorithm which considers location, orientation and arrangement of defects on the conveyed objects. Selective processing tool guided by the planed path is motion controlled

Comprehensive Use of Curvature for Robust and Accurate Online Surface Reconstruction

Interactive real-time scene acquisition from hand-held depth cameras has recently developed much momentum, enabling applications in ad-hoc object acquisition, augmented reality and other fields. A key challenge to online reconstruction remains error accumulation in the reconstructed camera trajectory, due to drift-inducing instabilities in the range scan alignments of the underlying iterative-closest-point (ICP) algorithm. Various strategies have been proposed to mitigate that drift, including SIFT-based pre-alignment, color-based weighting of ICP pairs, stronger weighting of edge features, and so on. In our work, we focus on surface curvature as a feature that is detectable on range scans alone and hence does not depend on accurate multi-sensor alignment. In contrast to previous work that took curvature into consideration, however, we treat curvature as an independent quantity that we consistently incorporate into every stage of the real-time reconstruction pipeline, including densely curvature-weighted ICP, range image fusion, local surface reconstruction, and rendering. Using multiple benchmark sequences, and in direct comparison to other state-of-the-art online acquisition systems, we show that our approach significantly reduces drift, both when analyzing individual pipeline stages in isolation, as well as seen across the online reconstruction pipeline as a whole

Achieving Efficient and Realistic Full-Radar Simulations and Automatic Data Annotation by Exploiting Ray Meta Data from a Radar Ray Tracing Simulator

In this work, a novel radar simulation concept for efficiently simulating realistic radar data for range, Doppler, and arbitrary antenna positions is introduced. With the concept, the simulated radar signal can also be automatically annotated by splitting it into multiple parts. Annotations that are almost perfect - including the annotation of exotic effects, such as multi-path - can be produced with this approach. Signal parts originating from different parts of an object can be labelled with it as well. To this end, the computation process used in a Monte Carlo shooting and bouncing rays (SBR) simulator is adapted. By considering the hits of each simulated ray, various meta data can be stored, such as hit position, mesh pointer, object IDs, and many more. This collected meta data can then be utilized to predict path-length changes caused by object motion to obtain Doppler information or to apply specific ray filter rules to obtain radar signals that only fulfil specific conditions, such as multiple bounces, or signals that contain specific object IDs. Using this approach, perfect, and otherwise almost impossible, annotation schemes can be realized

Room temperature high frequency transport of Dirac fermions in epitaxially grown Sb_2Te_3 based topological insulators

We report on the observation of photogalvanic effects in epitaxially grown Sb_2Te_3 three-dimensional (3D) topological insulators (TI). We show that asymmetric scattering of Dirac electrons driven back and forth by the terahertz electric field results in a dc electric current. Due to the "symmetry filtration" the dc current is generated in the surface electrons only and provides an opto-electronic access to probe the electric transport in TI, surface domains orientation and details of electron scattering even in 3D TI at room temperature where conventional surface electron transport is usually hindered by the high carrier density in the bulk

Interactive Exploration and Flattening of Deformed Historical Documents

We present an interactive application for browsing severely damaged documents and other cultural artefacts. Such documents often contain strong geometric distortions such as wrinkling, buckling, and shrinking and cannot be flattened physically due to the high risk of causing further damage. Previous methods for virtual restoration involve globally flattening a 3D reconstruction of the document to produce a static image. We show how this global approach can fail in cases of severe geometric distortion, and instead propose an interactive viewer which allows a user to browse a document while dynamically flattening only the local region under inspection. Our application also records the provenance of the reconstruction by displaying the reconstruction side by side with the original image data

ROZPROSZONA METODA DO SYMULACJI STANÓW PRZEJŚCIOWYCH DYNAMICZNIE UWZGLĘDNIAJĄCA DODATKOWE WYNIKI AUTONOMICZNYCH AGENTÓW PROGRAMOWYCH

Based on autonomous software agents capable of calculating individual numerical field problems, a distributed method for solving transient field problems is presented. The software agents are running on distributed resources connected via a network and represent a dynamic calculation environment. Communication and data exchange between multiple agents enables their collaboration and allows decisions based on distributed overall knowledge. As unique characteristics, no central unit influences the solution process at any time. The presented simulation example and its evaluated calculation process proves the method to benefit from redundant resources.W oparciu o autonomiczne agenty programowe zdolne do obliczania indywidualnych numerycznych problemów pola, przedstawiono rozproszoną metodę rozwiązywania stanów przejściowych pola. Agenty programowe działają na zasobach rozproszonych połączonych za pośrednictwem sieci i reprezentują środowisko obliczeń dynamicznych. Komunikacja i wymiana danych między wieloma agentami umożliwia ich współpracę i pozwala podejmować decyzje w oparciu o rozproszoną wiedzę ogólną. Jako unikalna charakterystyką jest fakt, że żadna jednostka centralna nie wpływa w żadnym momencie na proces rozwiązania. Przedstawiony przykład symulacji i jej oszacowany proces obliczeniowy dowodzi, że metoda umożliwia korzystanie z nadmiarowych zasobów

Ab initio calculations of the hydrogen bond

Recent x-ray Compton scattering experiments in ice have provided useful information about the quantum nature of the interaction between H$_2$O monomers. The hydrogen bond is characterized by a certain amount of charge transfer which could be determined in a Compton experiment. We use ab-initio simulations to investigate the hydrogen bond in H$_2$O structures by calculating the Compton profile and related quantities in three different systems, namely the water dimer, a cluster containing 12 water molecules and the ice crystal. We show how to extract estimates of the charge transfer from the Compton profiles.Comment: 16 pages, 7 figures, to appear in Phys. Rev.