Algorithms for the enhancement of dynamic range and colour constancy of digital images & video

One of the main objectives in digital imaging is to mimic the capabilities of the human eye, and perhaps, go beyond in certain aspects. However, the human visual system is so versatile, complex, and only partially understood that no up-to-date imaging technology has been able to accurately reproduce the capabilities of the it. The extraordinary capabilities of the human eye have become a crucial shortcoming in digital imaging, since digital photography, video recording, and computer vision applications have continued to demand more realistic and accurate imaging reproduction and analytic capabilities. Over decades, researchers have tried to solve the colour constancy problem, as well as extending the dynamic range of digital imaging devices by proposing a number of algorithms and instrumentation approaches. Nevertheless, no unique solution has been identified; this is partially due to the wide range of computer vision applications that require colour constancy and high dynamic range imaging, and the complexity of the human visual system to achieve effective colour constancy and dynamic range capabilities. The aim of the research presented in this thesis is to enhance the overall image quality within an image signal processor of digital cameras by achieving colour constancy and extending dynamic range capabilities. This is achieved by developing a set of advanced image-processing algorithms that are robust to a number of practical challenges and feasible to be implemented within an image signal processor used in consumer electronics imaging devises. The experiments conducted in this research show that the proposed algorithms supersede state-of-the-art methods in the fields of dynamic range and colour constancy. Moreover, this unique set of image processing algorithms show that if they are used within an image signal processor, they enable digital camera devices to mimic the human visual system s dynamic range and colour constancy capabilities; the ultimate goal of any state-of-the-art technique, or commercial imaging device

Response of sea bream to handling

Understanding how gilthead sea bream, Sparus aurata L., an important Mediterranean Sea species for aquaculture, respond physiologically to stressors commonly encountered in intensive rearing is important for eiective production, as managing for stress is a major factor in maintaining healthy ¢sh stocks. Our objective was to determine whether holding juvenile gilthead sea bream at a high density (HD), as a chronic stressor, would aiect their physiological responses to a subsequent acute handling stressor. After acclimation at a low density (LD) of 6k g m 3 in 200-L circular tanks containing 33^ 36 g L 1 recirculating seawater at 191C under a normal photoperiod, juvenile 37-g gilthead sea bream were con¢ned for 14 days at a HD of 26 kg m 3 an

Reliability-based dynamical design of a singular structure for use in High Energy Physics experiments

[EN] The present work presents a comprehensive design and dynamic calculation of singular metallic structures, part of the Neutrino Experiment NEXT. The experiment uses an electroluminescent TPC chamber, a high-pressure 136Xe gas vessel enclosing the detector. A lead-block "castle'' or containing box shields this vessel against external g-rays from all directions; in spite of its heavy weight, the castle must be regularly open for the detector maintenance. Since the structures will be constructed at a middle-level seismic localization (Laboratorio Subterraneo Canfranc, Spain), the earthquake hazard must be taken into account. Vessel and castle are supported by a rigid frame, which must satisfy two requirements: (i) the Spanish seismic standard, (ii) for equipment protection, the detector maximum horizontal acceleration must be < 1 [m/s(2)]. This frame rests on special base isolators to decrease horizontal accelerations in case of an earthquake. Three dynamical calculations are conducted: (i) a response spectrum analysis to comply with the standard, (ii) five time-history analyses to calculate tolerances and, (iii) a reliability-based approach using 1000 timehistory responses to ensure satisfaction of the operating requirements. The final outcome is the design of a singular structure optimized for the NEXT experiment with a probability of failure against any standard earthquake of only 0.125%. (C) 2017 Politechnika Wroclawska. Published by Elsevier Sp. z o.o. All rights reserved.This research was supported by the grants CSD2008-00037 Canfranc Underground Physics.Palma, R.; Torrent, J.; Pérez-Aparicio, JL.; Ripoll, L. (2018). Reliability-based dynamical design of a singular structure for use in High Energy Physics experiments. Archives of Civil and Mechanical Engineering. 18(1):256-266. https://doi.org/10.1016/j.acme.2017.07.00325626618

Subjectively optimised multi-exposure and multi-focus image fusion with compensation for camera shake

Multi-exposure image fusion algorithms are used for enhancing the perceptual quality of an image captured by sensors of limited dynamic range. This is achieved by rendering a single scene based on multiple images captured at different exposure times. Similarly, multi-focus image fusion is used when the limited depth of focus on a selected focus setting of a camera results in parts of an image being out of focus. The solution adopted is to fuse together a number of multi-focus images to create an image that is focused throughout. In this paper we propose a single algorithm that can perform both multi-focus and multi-exposure image fusion. This algorithm is a novel approach in which a set of unregistered multiexposure/focus images is first registered before being fused. The registration of images is done via identifying matching key points in constituent images using Scale Invariant Feature Transforms (SIFT). The RANdom SAmple Consensus (RANSAC) algorithm is used to identify inliers of SIFT key points removing outliers that can cause errors in the registration process. Finally we use the Coherent Point Drift algorithm to register the images, preparing them to be fused in the subsequent fusion stage. For the fusion of images, a novel approach based on an improved version of a Wavelet Based Contourlet Transform (WBCT) is used. The experimental results as follows prove that the proposed algorithm is capable of producing HDR, or multi-focus images by registering and fusing a set of multi-exposure or multi-focus images taken in the presence of camera shake

Polarization conversion spectroscopy of hybrid modes

Enhanced polarization conversion in reflection for the Otto and Kretschmann configurations is introduced as a new method for hybrid-mode spectroscopy. Polarization conversion in reflection appears when hybrid-modes are excited in a guiding structure composed of at least one anisotropic media. In contrast to a dark dip, in this case modes are associated to a peak in the converted reflectance spectrum, increasing the detection sensitivity and avoiding confusion with reflection dips associated with other processes as can be transmission.Comment: 4 pages, 4 figure

Effect of Background, Attitudinal and Social Network Variables on PhD Students’ Academic Performance. A Multimethod Approach

The aim of this paper is to predict the academic performance of PhD students understood as publications and presentations at conferences. MATERIALS AND METHODS: We use a multimethod approach, a quantitative web survey of PhD students and their supervisors and in-depth interviews. We surveyed all PhD students at the University of Girona (Spain) in their 4th and 5th year, who held either a PhD grant or a teaching position at the university. RESULTS: The explanatory variables of PhD performance are of three types: characteristics of the PhD students’ research groups understood as social networks, background variables and attitudinal characteristics. The quantitative analyses show the importance of some background and attitudinal variables like supervisor performance, having a grant, or motivation. The qualitative results show networking to be also important. Policy implications are drawn at country and university level. DISCUSSION: Policy implications are drawn at country and university level

Vivimos ante un paradigma de cambio constante o un cambio de paradigma: «Blockchain» y su promesa transformadora

La crisis financiera de 2008 puso en entredicho la eficiencia del sistema monetario. Ese shock desembocó en una innovsación sin precedentes en el uso de financas y tecnología, y en nuevos modelos e negocio