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Author: Adam Kirk Publisher: ISBN: Category : Languages : en Pages : 104
Book Description
We present a perceptually based algorithm for modeling the color shift that occurs for human viewers in low-light scenes. Known as the Purkinje effect, this color shift occurs as the eye transitions from photopic, cone-mediated vision in well-lit scenes to scotopic, rod-mediated vision in dark scenes. At intermediate light levels vision is mesopic with both the rods and cones active. Although the rods have a spectral response distinct from the cones, they still share the same neural pathways. As light levels decrease and the rods become increasingly active they cause a perceived shift in color. We model this process so that we can compute perceived colors for mesopic and scotopic scenes from spectral data. While our tone mapping operator works with spectral data from any source, we show how to produce spectral data of static scenes using multiple images and a camera with known spectral sensitivity. If the spectral sensitivity isn't provided by the camera manufacturer, we describe a one-time calibration procedure to estimate the sensitivity. Should obtaining spectral data of a scene be infeasible, we also describe how the effect can be approximated from high dynamic range RGB images by learning a mapping from RGB to rod and cone responses. Once we have determined rod and cone responses either directly or through our approximation process, we map them to RGB values that can be displayed on a standard monitor to elicit the same color perception when viewed photopically. Our tone mapping method focuses on computing the color shift associated with low-light conditions and leverages current HDR techniques to control the image dynamic range. We include results generated from both spectral and RGB images as well as experimental data.
Author: Adam Kirk Publisher: ISBN: Category : Languages : en Pages : 104
Book Description
We present a perceptually based algorithm for modeling the color shift that occurs for human viewers in low-light scenes. Known as the Purkinje effect, this color shift occurs as the eye transitions from photopic, cone-mediated vision in well-lit scenes to scotopic, rod-mediated vision in dark scenes. At intermediate light levels vision is mesopic with both the rods and cones active. Although the rods have a spectral response distinct from the cones, they still share the same neural pathways. As light levels decrease and the rods become increasingly active they cause a perceived shift in color. We model this process so that we can compute perceived colors for mesopic and scotopic scenes from spectral data. While our tone mapping operator works with spectral data from any source, we show how to produce spectral data of static scenes using multiple images and a camera with known spectral sensitivity. If the spectral sensitivity isn't provided by the camera manufacturer, we describe a one-time calibration procedure to estimate the sensitivity. Should obtaining spectral data of a scene be infeasible, we also describe how the effect can be approximated from high dynamic range RGB images by learning a mapping from RGB to rod and cone responses. Once we have determined rod and cone responses either directly or through our approximation process, we map them to RGB values that can be displayed on a standard monitor to elicit the same color perception when viewed photopically. Our tone mapping method focuses on computing the color shift associated with low-light conditions and leverages current HDR techniques to control the image dynamic range. We include results generated from both spectral and RGB images as well as experimental data.
Author: Francesco Banterle Publisher: CRC Press ISBN: 1498706959 Category : Computers Languages : en Pages : 337
Book Description
This book explores the methods needed for creating and manipulating HDR content. HDR is a step change from traditional imaging; more closely matching what we see with our eyes. In the years since the first edition of this book appeared, HDR has become much more widespread, moving from a research concept to a standard imaging method. This new edition incorporates all the many developments in HDR since the first edition and once again emphasizes practical tips, including the authors' popular HDR Toolbox (available on the authors' website) for MATLAB and gives readers the tools they need to develop and experiment with new techniques for creating compelling HDR content. Key Features: Contains the HDR Toolbox for readers' experimentation on authors' website Offers an up-to-date, detailed guide to the theory and practice of high dynamic range imaging Covers all aspects of the field, from capture to display Provides benchmarks for evaluating HDR imagery
Author: Nobuhiko Mukai Publisher: BoD – Books on Demand ISBN: 9535104551 Category : Computers Languages : en Pages : 270
Book Description
Computer graphics is now used in various fields; for industrial, educational, medical and entertainment purposes. The aim of computer graphics is to visualize real objects and imaginary or other abstract items. In order to visualize various things, many technologies are necessary and they are mainly divided into two types in computer graphics: modeling and rendering technologies. This book covers the most advanced technologies for both types. It also includes some visualization techniques and applications for motion blur, virtual agents and historical textiles. This book provides useful insights for researchers in computer graphics.
Author: Sam Birley Publisher: LAP Lambert Academic Publishing ISBN: 9783846559734 Category : Languages : en Pages : 96
Book Description
Tone-mapping is essential for photorealistic interactive applications, such as games or walkthroughs, as it allows for physically-based simulations of light to be rendered in a perceptually accurate manner. However, most currently existing tone-mapping operators fail to integrate well into real-time applications; their designs do not take temporal coherency into account. We demonstrate that it is possible to improve the temporal coherence of many tone-mapping operators using a generalised time-dependant framework designed for temporally varying HDR content. The framework also accounts for adaptation over time to the prevailing luminance in a scene, allowing an additional measure of psychophysical accuracy to be added to operators that was not present in their original design. The generalised framework is applied to both spatially uniform and spatially varying operators within an interactive application, which is used to conduct a study of their real-time performance; both in terms of efficiency and perceptual preference.
Author: Alessandro Artusi Publisher: CRC Press ISBN: 1482249928 Category : Computers Languages : en Pages : 238
Book Description
In recent years visual devices have proliferated, from the massive high-resolution, high-contrast screens to the tiny ones on mobile phones, with their limited dynamic range and color gamut. The wide variety of screens on which content may be viewed creates a challenge for developers. Adapting visual content for optimized viewing on all devices is called retargeting. This is the first book to provide a holistic view of the subject, thoroughly reviewing and analyzing the many techniques that have been developed for retargeting along dimensions such as color gamut, dynamic range, and spatial resolution.
Author: Frédéric Dufaux Publisher: Academic Press ISBN: 0128030399 Category : Computers Languages : en Pages : 631
Book Description
At the time of rapid technological progress and uptake of High Dynamic Range (HDR) video content in numerous sectors, this book provides an overview of the key supporting technologies, discusses the effectiveness of various techniques, reviews the initial standardization efforts and explores new research directions in all aspects involved in HDR video systems. Topics addressed include content acquisition and production, tone mapping and inverse tone mapping operators, coding, quality of experience, and display technologies. This book also explores a number of applications using HDR video technologies in the automotive industry, medical imaging, spacecraft imaging, driving simulation and watermarking. By covering general to advanced topics, along with a broad and deep analysis, this book is suitable for both the researcher new or familiar to the area. With this book the reader will: Gain a broad understanding of all the elements in the HDR video processing chain Learn the most recent results of ongoing research Understand the challenges and perspectives for HDR video technologies Covers a broad range of topics encompassing the whole processing chain in HDR video systems, from acquisition to display Provides a comprehensive overview of this fast emerging topic Presents upcoming applications taking advantages of HDR
Author: Fouad Sabry Publisher: One Billion Knowledgeable ISBN: Category : Computers Languages : en Pages : 98
Book Description
What is Tone Mapping Tone mapping is a technique used in image processing and computer graphics to map one set of colors to another to approximate the appearance of high-dynamic-range (HDR) images in a medium that has a more limited dynamic range. Print-outs, CRT or LCD monitors, and projectors all have a limited dynamic range that is inadequate to reproduce the full range of light intensities present in natural scenes. Tone mapping addresses the problem of strong contrast reduction from the scene radiance to the displayable range while preserving the image details and color appearance important to appreciate the original scene content. How you will benefit (I) Insights, and validations about the following topics: Chapter 1: Tone_mapping Chapter 2: Gamma_correction Chapter 3: Multi-exposure_HDR_capture Chapter 4: High-dynamic-range_rendering Chapter 5: Shadow_and_highlight_enhancement Chapter 6: High_dynamic_range Chapter 7: Tone_reproduction Chapter 8: Luminance_HDR Chapter 9: Aurora_HDR Chapter 10: EasyHDR (II) Answering the public top questions about tone mapping. (III) Real world examples for the usage of tone mapping in many fields. Who this book is for Professionals, undergraduate and graduate students, enthusiasts, hobbyists, and those who want to go beyond basic knowledge or information for any kind of Tone Mapping.
Author: Gabriel Eilertsen Publisher: Linköping University Electronic Press ISBN: 9176853020 Category : Languages : en Pages : 155
Book Description
Techniques for high dynamic range (HDR) imaging make it possible to capture and store an increased range of luminances and colors as compared to what can be achieved with a conventional camera. This high amount of image information can be used in a wide range of applications, such as HDR displays, image-based lighting, tone-mapping, computer vision, and post-processing operations. HDR imaging has been an important concept in research and development for many years. Within the last couple of years it has also reached the consumer market, e.g. with TV displays that are capable of reproducing an increased dynamic range and peak luminance. This thesis presents a set of technical contributions within the field of HDR imaging. First, the area of HDR video tone-mapping is thoroughly reviewed, evaluated and developed upon. A subjective comparison experiment of existing methods is performed, followed by the development of novel techniques that overcome many of the problems evidenced by the evaluation. Second, a largescale objective comparison is presented, which evaluates existing techniques that are involved in HDR video distribution. From the results, a first open-source HDR video codec solution, Luma HDRv, is built using the best performing techniques. Third, a machine learning method is proposed for the purpose of reconstructing an HDR image from one single-exposure low dynamic range (LDR) image. The method is trained on a large set of HDR images, using recent advances in deep learning, and the results increase the quality and performance significantly as compared to existing algorithms. The areas for which contributions are presented can be closely inter-linked in the HDR imaging pipeline. Here, the thesis work helps in promoting efficient and high-quality HDR video distribution and display, as well as robust HDR image reconstruction from a single conventional LDR image.
Author: Adam Kirk
Author: Adam Kirk
Author: 廖家麟
Author: Francesco Banterle
Author: Nobuhiko Mukai
Author: Sam Birley
Author: Alessandro Artusi
Author: Frédéric Dufaux
Author: Fouad Sabry
Author: Stephen B. Chisholm
Author: Gabriel Eilertsen