Detection and Identification Techniques for Markers Used in Computer Vision

This paper summarizes and compares techniques for detecting and identifying markers in the context of computer vision. Existing approaches either use correlation, digital or topological methods for marker identification. The comparison points out, that all marker processing algorithms which employ sophisticated digital codes perform more robust and reliable. Existing bit representation schemes for these codes and marker designs are compared with each other. In the overall context it is illustrated, why the marker processing algorithm is the best performer regarding marker occlusion and minimal detectable pattern size

Markerless Camera Pose Estimation - An Overview

As shown by the human perception, a correct interpretation of a 3D scene on the basis of a 2D image is possible without markers. Solely by identifying natural features of different objects, their locations and orientations on the image can be identified. This allows a three dimensional interpretation of a two dimensional pictured scene. The key aspect for this interpretation is the correct estimation of the camera pose, i.e. the knowledge of the orientation and location a picture was recorded. This paper is intended to provide an overview of the usual camera pose estimation pipeline as well as to present and discuss the several classes of pose estimation algorithms

Sequentiality of String-to-Context Transducers

Transducers extend finite state automata with outputs, and describe transformations from strings to strings. Sequential transducers, which have a deterministic behaviour regarding their input, are of particular interest. However, unlike finite-state automata, not every transducer can be made sequential. The seminal work of Choffrut allows to characterise, amongst the functional one-way transducers, the ones that admit an equivalent sequential transducer. In this work, we extend the results of Choffrut to the class of transducers that produce their output string by adding simultaneously, at each transition, a string on the left and a string on the right of the string produced so far. We call them the string-to-context transducers. We obtain a multiple characterisation of the functional string-to-context transducers admitting an equivalent sequential one, based on a Lipschitz property of the function realised by the transducer, and on a pattern (a new twinning property). Last, we prove that given a string-to-context transducer, determining whether there exists an equivalent sequential one is in coNP

Комп’ютерна система реєстрації та аналізу біоелектричних сигналів

We present a new method for matching a region between an input and a query image, based on the P-channel representation of pixel-based image features such as grayscale and color information, local gradient orientation and local spatial coordinates. We introduce the concept of integral P-channels, which conciliates the concepts of P-channel and integral images. Using integral images, the P-channel representation of a given region is extracted with a few arithmetic operations. This enables a fast nearest-neighbor search in all possible target regions. We present extensive experimental results and show that our approach compares favorably to existing methods for region matching such as histograms or region covariance.DIPLEC

Citations des revues de paléontologie : bilan 2005

L'Association Paléontologique Française (APF) propose un bilan annuel des citations d'une trentaine de revues, dont une dizaine française. En voici le bilan 2005. Cet index de l'APF ne cherche pas à se substituer au facteur d'impact (FI) fourni par l'ISI, mais plutôt à fournir un document de référence fiable à l'échelle de la paléontologie. Le fait de disposer d'un index de citation interne à cette discipline apparait plus utile et plus approprié pour la hiérarchisation de ces revues disciplinaires que le FI officiel qui intègre dans une même hiérarchie des revues de disciplines diverses aux communautés hétérogènes en nombre de chercheurs, ce nombre étant corrélé avec le FI

Cr2C3–NiCr VPS thermal spray coatings as candidate for chromium replacement

The present investigation has been carried out with the aim of determining the tribological behavior of a VPS chromium carbide coating both in the as-deposited and heat-treated conditions. A commercial powder of Cr2C3–25% NiCr was sprayed employing a VPS system (Medicoat AG, Switzerland) onto plain low carbon steel coupons. The samples were subsequently annealed for 2 h at 600 °C, 800 °C and 900 °C in Ar. The microstructural characterization was carried out by using SEM and XRD before and after the heat treatment of the samples. SEM observations were employed for determining the degradation mechanisms that took place during the wear tests. When the coated systems rubbed against alumina under a 5 N normal load in air, a progressive change in the mechanism, from a mixed adhesive and abrasive, to a predominant abrasive was observed, as the heat treatment temperature increased. The wear constants were found to be of the order of approximately 10− 6 mm3/N.m, which indicates a wear resistance of nearly 4 times higher in comparison with the wear results reported in the literature for similar coating systems obtained by employing HVOF deposition. However, the heat treatment carried out at 900 °C brought about only 20% increase in the sliding wear resistance of the coated system

CRAS et Palevol : bilan 2002

L'Association Paléontologique Française (APF) propose un bilan annuel des citations d'une trentaine de revues, dont une dizaine française. En voici le bilan 2003. Cet index de l'APF ne cherche pas à se substituer au facteur d'impact (FI) fourni par l'ISI, mais plutôt à fournir un document de référence fiable à l'échelle de la paléontologie. Le fait de disposer d'un index de citation interne à cette discipline apparait plus utile et plus approprié pour la hiérarchisation de ces revues disciplinaires que le FI officiel qui intègre dans une même hiérarchie des revues de disciplines diverses aux communautés hétérogènes en nombre de chercheurs, ce nombre étant corrélé avec le FI