Light Field Methods for the Visual Inspection of Transparent Objects PDF Download
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Author: Meyer, Johannes
Publisher: KIT Scientific Publishing
ISBN: 3731509121
Category : Science
Languages : en
Pages : 268
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Book Description
Author: Meyer, Johannes
Publisher: KIT Scientific Publishing
ISBN: 3731509121
Category : Science
Languages : en
Pages : 268
Get Book Here
Book Description
Author: Grégoire Nieto
Publisher:
ISBN:
Category :
Languages : fr
Pages : 0
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Book Description
Les champs de lumière ont attisé la curiosité durant ces dernières décennies. Capturés par une caméra plénoptique ou un ensemble de caméras, ils échantillonnent la fonction plénoptique qui informe sur la radiance de n'importe quel rayon lumineux traversant la scène observée. Les champs lumineux offrent de nombreuses applications en vision par ordinateur comme en infographie, de la reconstruction 3D à la segmentation, en passant par la synthèse de vue, l'inpainting ou encore le matting par exemple.Dans ce travail nous nous attelons au problème de reconstruction du champ de lumière dans le but de synthétiser une image, comme si elle avait été prise par une caméra plus proche du sujet de la scène que l'appareil de capture plénoptique. Notre approche consiste à formuler la reconstruction du champ lumineux comme un problème de rendu basé image (IBR). La plupart des algorithmes de rendu basé image s'appuient dans un premier temps sur une reconstruction 3D approximative de la scène, appelée proxy géométrique, afin d'établir des correspondances entre les points image des vues sources et ceux de la vue cible. Une nouvelle vue est générée par l'utilisation conjointe des images sources et du proxy géométrique, bien souvent par la projection des images sources sur le point de vue cible et leur fusion en intensité.Un simple mélange des couleurs des images sources ne garantit pas la cohérence de l'image synthétisée. Nous proposons donc une méthode de rendu direct multi-échelles basée sur les pyramides de laplaciens afin de fusionner les images sources à toutes les fréquences, prévenant ainsi l'apparition d'artefacts de rendu.Mais l'imperfection du proxy géométrique est aussi la cause d'artefacts de rendu, qui se traduisent par du bruit en haute fréquence dans l'image synthétisée. Nous introduisons une nouvelle méthode de rendu variationnelle avec des contraintes sur les gradients de l'image cible dans le but de mieux conditionner le système d'équation linéaire à résoudre et supprimer les artefacts de rendu dus au proxy.Certaines scènes posent de grandes difficultés de reconstruction du fait du caractère non-lambertien éventuel de certaines surfaces~; d'autre part même un bon proxy ne suffit pas, lorsque des réflexions, transparences et spécularités remettent en cause les règles de la parallaxe. Nous proposons méthode originale basée sur l'approximation locale de l'espace plénoptique à partir d'un échantillonnage épars afin de synthétiser n'importe quel point de vue sans avoir recours à la reconstruction explicite d'un proxy géométrique. Nous évaluons notre méthode à la fois qualitativement et quantitativement sur des scènes non-triviales contenant des matériaux non-lambertiens.Enfin nous ouvrons une discussion sur le problème du placement optimal de caméras contraintes pour le rendu basé image, et sur l'utilisation de nos algorithmes pour la vision d'objets dissimulés derrière des camouflages.Les différents algorithmes proposés sont illustrés par des résultats sur des jeux de données plénoptiques structurés (de type grilles de caméras) ou non-structurés.
Author: Uhlig, David
Publisher: KIT Scientific Publishing
ISBN: 3731513064
Category :
Languages : en
Pages : 284
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Book Description
Optical measurement methods are becoming increasingly important for high-precision production of components and quality assurance. The increasing demand can be met by modern imaging systems with advanced optics, such as light field cameras. This work explores their use in the deflectometric measurement of specular surfaces. It presents improvements in phase unwrapping and calibration techniques, enabling high surface reconstruction accuracies using only a single monocular light field camera.
Author: Shiqi Yu
Publisher: Springer Nature
ISBN: 3031189167
Category : Computers
Languages : en
Pages : 752
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Book Description
The 4-volume set LNCS 13534, 13535, 13536 and 13537 constitutes the refereed proceedings of the 5th Chinese Conference on Pattern Recognition and Computer Vision, PRCV 2022, held in Shenzhen, China, in November 2022. The 233 full papers presented were carefully reviewed and selected from 564 submissions. The papers have been organized in the following topical sections: Theories and Feature Extraction; Machine learning, Multimedia and Multimodal; Optimization and Neural Network and Deep Learning; Biomedical Image Processing and Analysis; Pattern Classification and Clustering; 3D Computer Vision and Reconstruction, Robots and Autonomous Driving; Recognition, Remote Sensing; Vision Analysis and Understanding; Image Processing and Low-level Vision; Object Detection, Segmentation and Tracking.
Author: Ana Paula Cláudio
Publisher: Springer Nature
ISBN: 3030415902
Category : Computers
Languages : en
Pages : 629
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Book Description
This book constitutes thoroughly revised and selected papers from the 14th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications, VISIGRAPP 2019, held in Prague, Czech Republic, in February 2019. The 25 thoroughly revised and extended papers presented in this volume were carefully reviewed and selected from 395 submissions. The papers contribute to the understanding of relevant trends of current research on computer graphics; human computer interaction; information visualization; computer vision.
Author: Gábor Horváth
Publisher: Springer
ISBN: 3642547184
Category : Science
Languages : en
Pages : 652
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Book Description
This book covers advances made since the 2004 Springer volume “Polarized Light in Animal Vision” edited by Horvath and Varju, but also provides reviews and synopses of some areas. Part I examines polarization sensitivity across many animal taxa including vertebrates and invertebrates and details both terrestrial and aquatic life. Part II is devoted to the description of polarized light in nature and explores how the physics of light must be taken into account when understanding how polarized light is detected by the visual system. This includes underwater polarization due to scattering; polarization patterns reflected from freshwater bodies; polarization characteristics of forest canopies; normal and anomalous polarization patterns of the skies; skylight polarization transmitted through Snell’s window and both linearly and circularly polarized signals produced by terrestrial and aquatic animals. This Part also examines polarized “light pollution” induced by anthropogenic factors such as reflection off asphalt surfaces, glass panes, car bodies, and other man-made structures that are now known to form ecological traps for polarotactic insects. Part III surveys some of the practical applications of polarization vision including polarization-based traps for biting insects, ground-based polarimetric cloud detectors and an historical examination of the navigational abilities of Viking seafarers using the sky polarization compass. The deterrent qualities of ungulate pelage to polarization-sensitive biting insects is also examined in this section.
Author: Yunlin Zhang
Publisher: MDPI
ISBN: 3038425087
Category : Science
Languages : en
Pages : 437
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Book Description
This book is a printed edition of the Special Issue "Water Optics and Water Colour Remote Sensing" that was published in Remote Sensing
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 388
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Book Description
Author: Merrill J. Allen
Publisher:
ISBN:
Category : Astronautics
Languages : en
Pages : 42
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Book Description
"A study of the visual performance through five regularly available ophthalmic filter glasses, five identical filter glasses uniformly coated to 10 percent transmission, and five other identical filter glasses with a gradient density coating transmitting 10 percent in the center of the lens and about 0. 1 percent at the top of the lens was made using a 7- by 8- by 24-foot atmosphere chamber to simulate flight under adverse glare conditions. Controlled atmospheric conditions and chamber wall luminances of 7000 foot-lamberts and 400 foot-lamberts were provided. The far point test target was a threshold 1/2° white spot variable in brightness relative to the surround. The near target was a randomly presented number target set in a Link Trainer instrument panel. Panel luminances ranging from 0.1 to 0.43 percent of fog room wall luminances were provided and the subject's response time to adapt to the near target after adjusting the threshold spot at distance was the measure of visual performance through the specific filter being worn. Six subjects were used. Approximately 10, 000 judgments were recorded and analyzed for this study. The average time (under average experimental conditions using all subjects) required to identify a target on the instrument panel without sunglasses was 0.5994 sec.; with ordinary sunglasses, 0.6093 sec.; with uniform coating, 0.7603 sec.; and with gradient coating, 0.5057 sec. These include over 300 findings for the "no sunglasses" to 1800 findings for the gradient coating. Differences in performance could be accounted for on the basis of overall transmission effects without regard to filter color. All observers disliked the yellow filters. Threshold distant target recognition through gradient density filters was the poorest at low levels but the best at high levels by a narrow margin. Vision tended to be as good or better unaided than with most filters for a distant threshold target at about 490 foot-lamberts. However, at about 7000 foot-lamberts, the gradient density filter was again superior."--Abstract.
Author: Gábor Horváth
Publisher: Springer Science & Business Media
ISBN: 3662093871
Category : Science
Languages : en
Pages : 465
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Book Description
The subject of this volume is two-fold. First, it gathers typical polarization patterns occurring in nature. Second, it surveys the polarization-sensitive ani mals, the physiological mechanisms and biological functions of polarization sensitivity as weIl as the polarization-guided behaviour in animals. The monograph is prepared for biologists, physicists and meteorologists, espe cially for experts of atmospheric optics and animal vision, who wish to under stand and reveal the message hidden in polarization patterns of the optical environment not directly accessible to the human visual system, but measur able by polarimetry and perceived by many animals. Our volume is an attempt to build a bridge between these two physical and biological flelds. In Part I we introduce the reader to the elements of imaging polarimetry. This technique can be efflciently used, e. g. in atmospheric optics, remote sens ing and biology. In Part 11 we deal with typical polarization patterns of the natural optical environment. Sunrise/sunset, clear skies, cloudy skies, moonshine and total solar eclipses all mean quite different illumination conditions, wh ich also affect the spatial distribution and strength of celestial polarization. We pre sent the polarization patterns of the sky and its unpolarized (neutral) points under sunlit, moonlit, clear, cloudy and eclipsed conditions as a function of solar elevation. The polarization pattern of a rainbow is also shown. That part of the spectrum is derived in which perception of skylight polarization is optimal under partly cloudy skies.
