Olivier Demuynck

Universidad Politécnica de Madrid, Madrid, Madrid, Spain

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Publications (8)15.04 Total impact

  • O. Demuynck · J.M. Menendez
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    ABSTRACT: Augmented reality (AR) commonly uses markers for detection and tracking. Such multimedia applications associate each marker with a virtual 3D model stored in the memory of the camera-equipped device running the application. Application users are limited in their interactions, which require knowing how to design and program 3D objects. This generally prevents them from developing their own entertainment AR applications. The Magic Cards application solves this problem by offering an easy way to create and manage an unlimited number of virtual objects that are encoded on special markers.
    IEEE Computer Graphics and Applications 01/2013; 33(1):12-19. DOI:10.1109/MCG.2012.94 · 1.12 Impact Factor
  • Olivier Demuynck · José Manuel Menéndez
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    ABSTRACT: Complying with security certifications in most harsh industrial areas is usually very expensive and sometimes hinders the industrialization of new technologies. Thus, we observe in the modern industry an increasing need for visual inspection and closed monitoring systems, either manual (direct and permanent observation of a supervisor) or automatic (usually through Computer Vision applications) to monitor hazardous environments. In such conditions, the use of incoherent optical fiber bundle (IOFB) for image transmission is probably the most appropriate solution. This option requires a prior calibration step to perform the reconstruction of the IOFB output image, where the reconstruction process is very efficient, according to the latest studies. It is of further interest to introduce and extend this technique in industrial applications, to make possible the portability of IOFB calibration. Indeed, a slight position shift of the system may corrupt the calibrated IOFB, consequently invalidating it for image transmission. We propose a new method to quickly and automatically solve this problem. Such an image acquisition and transmission system is very attractive for commercial introduction, since the IOFB can be pre-calibrated, and the calibration quickly recomputed any time it is needed without loss in image quality. The presented work has been submitted for patent.
    Optical Engineering 01/2012; 51(1):5001-. DOI:10.1117/1.OE.51.1.015001 · 0.96 Impact Factor
  • Olivier Demuynck · José Manuel Menéndez
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    ABSTRACT: Computer vision, despite all the recent progress, still cannot be employed technically in most hazardous and harsh industrial areas. Most of the alternative solutions to this modern issue are usually unavailable mainly due to the global visual inspection solution cost. The best suitable option is the use of an incoherent optical fiber bundle (IOFB) that obviously requires a calibration step before image transmission purpose. We already presented our contribution to this topic improving the calibration method of the IOFB for image transmission, with some additional and essential steps that considerably improve the reconstructed image quality while also drastically reducing the processing time needed. We also proposed and evaluated a new full-resolution calibration method in a very recent study. We present and discuss in this paper an application using the IOFB for robot guiding in hazardous areas, based on a stereoscopic vision system. Conclusions compare the low- and full-resolution IOFB calibration methods for the depicted application and introduce some advantages of a specially designed IOFB that could perfectly fit with some industrial applications.
    Applied Optics 05/2011; 50(15):2274-82. DOI:10.1364/AO.50.002274 · 1.78 Impact Factor
  • Olivier Demuynck · José M. Menéndez
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    ABSTRACT: Computer vision, despite all the recent progress, still cannot be employed technically in most hazardous and highly industrialized areas. Most of the alternative solutions to this modern issue are usually unavailable mainly due to the elevated cost of the overall visual inspection solution. The most suitable option is the use of an incoherent optical fiber bundle (IOFB), which clearly requires a calibration step prior to image transmission. This technique has been presented previously and has received national and international patents. We also contributed strongly to the improvement of this image transmission technique through IOFB. Thus, we summarize our chosen IOFB calibration method and associated essential steps that definitively improve the reconstructed image quality. Furthermore, by employing the new optimal steps combination that we introduce, we also drastically reduce the processing time needed to calibrate and reconstruct an IOFB-transmitted output image compared to previous proposals. Finally, we present a new full-resolution method, which also requires the previously described and optimized calibration methods, to achieve a higher image definition.
    Optical Engineering 03/2011; 50(3):3601-. DOI:10.1117/1.3551498 · 0.96 Impact Factor
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    ABSTRACT: Cognitive processes require a functional interaction between specialized multiple, local and remote brain regions. Although these interactions can be strongly altered by an acquired brain injury, brain plasticity allows network reorganization to be principally responsible for recovery. The present work evaluates the impact of brain injury on functional connectivity patterns. Networks were calculated from resting-state magnetoencephalographic recordings from 15 brain injured patients and 14 healthy controls by means of wavelet coherence in standard frequency bands. We compared the parameters defining the network, such as number and strength of interactions as well as their topology, in controls and patients for two conditions: following a traumatic brain injury and after a rehabilitation treatment. A loss of delta- and theta-based connectivity and conversely an increase in alpha- and beta-band-based connectivity were found. Furthermore, connectivity parameters approached controls in all frequency bands, especially in slow-wave bands. A correlation between network reorganization and cognitive recovery was found: the reduction of delta-band-based connections and the increment of those based on alpha band correlated with Verbal Fluency scores, as well as Perceptual Organization and Working Memory Indexes, respectively. Additionally, changes in connectivity values based on theta and beta bands correlated with the Patient Competency Rating Scale. The current study provides new evidence of the neurophysiological mechanisms underlying neuronal plasticity processes after brain injury, and suggests that these changes are related with observed changes at the behavioural level.
    Brain 08/2010; 133(Pt 8):2365-81. DOI:10.1093/brain/awq174 · 10.23 Impact Factor
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    Olivier Demuynck · Carlos Pacheco Cedeño · Allison L Moore
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    ABSTRACT: Machine Vision for industrial applications requires simple-to-use and robust solutions. Usually industrial machine vision solutions are reduced to a simple 2D application, for which algorithm robustness has already been fully demonstrated, and where a key part of all those visual inspection systems is the efficient commercially-available illumination control systems that ensure the repeatability of captured image intensity. Nevertheless these projects sometimes require the 3D information for applications such as pick and place robotics, and this field of applications is not yet covered by most of the commercial industrial vision brands which actually tend to simplify the programmable visual device and its associated functions. We present in this paper a new fast and robust 3D localization method based on object edge. This process offers an infinite number of possible cases of industrial applications when 3D localization is required, but could also be employed for 3D classification, for example in case of the food industry when fruits are selected depending on their size and must be localized because of the random distribution on a conveyor belt. The presented industrial machine vision system is easy and fast to implement. It results in a robust, precise, and inexpensive industrial solution.
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    O. Demuynck · J. M. Menéndez
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    ABSTRACT: Artificial vision, in spite of all theoretical and practical progress accomplished during last thirty years, still cannot be employed technically in some hazardous and strong industrial areas, where conditions are such that cameras would not operate properly. Possible alternatives on such problem are the quite recent IP65 and IP67 industrial cameras, and associated connectors, protected by an anticorrosive, waterproof, and high temperatures resistive carcass employing a dedicated electronic, in addition robust to almost 3G accelerations. Nevertheless, such cameras are still very expensive compared to conventional industrial cameras and would still not be enough in hardest conditions (explosive gas or dust environment) or in electromagnetic interferences environments. A good alternative in extreme conditions is the use of optical fiber bundle. Since such cable only transmits light, they intrinsically have electromagnetic interferences immunity and, depending on the fiber material, could be exposed to very high temperature (over 1000°C for sapphire fibers for example), could be employed in almost all corrosive, environment, and totally submersible. Nevertheless, the coherent optical fiber bundles are very expensive, and for large distances could be non-competitive facing the other hardware solutions (armor plating, electromagnetic interferences isolation). Thus, the best suitable option to develop a competitive system in those particular cases is the use of incoherent optical fiber bundle (IOFB), nowadays just we discuss in this paper. Improvement of the noisy resulting quality image is also exposed here, achieved by experimental post calibration methods. We propose in this work a new calibration method of incoherent optical fiber bundle (IOFB) for image transmission purpose. Firstly, we present the calibration method (an enhancement of previously published calibration methods), some resulting reconstructed image and a discussion on its quality improvement employing simple denoising methods assisted by low pass filters (smooth filter, resizing method,...). We finally depict the two post calibration method are: correction of the input plane optical aberrations and extraction of a unique pixel (almost centered) for each fibers. We finally present some resulting images that demonstrate how it efficiently refine the reconstruction Look Up Table (LUT) used for the output image reconstruction improving image quality, image contrast but also reconstruction processing time.
    WSEAS Transactions on Signal Processing 09/2008; 4(9):531-541.
  • Olivier Demuynck · Nazareth Castellanos
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    ABSTRACT: This paper presents a method for image positioning, and map creation. The images are captured by a flying modulo equipped by a camera to observe a selected area. In this study we suppose this system is located at a fixed height, and compare its mechanism to a free pendulum moving with the wind force. The camera is always pointing vertically thanks to a motored system. This system isn't noise free and has a positioning error range, and so it requires a software correction to carry out this mapping from a continuous transmission of pictures. The goal of this study is to allow the user to easily watch a coherent sequence of images to observe and follow a moving target. The implemented algorithm, detailed in the further sections, compute first the interest points, finds then their match without using correlation (which speed up the treatment), solve the mathematical system of equations to obtain the translation and rotation that suffered the two successive pictures, and interprets the result for its representation for the user. In this study, we checked the well functioning of this method for a few sorts of grounds (city, forest, or desert) which allow us to conclude on the high efficiency with a high speed processing.
    Proceedings of the 8th conference on Signal processing, computational geometry and artificial vision; 08/2008