Color Constancy for RGB and Multispectral Images


Book Description

The problem of inferring the light color for a scene is called Illuminant Estimation. This step forms the first task in many workflows in the larger task of discounting the effect of the color of the illuminant, which is called Color Constancy. Illuminant Estimation is typically used as a pre-processing step in many computer vision tasks. In this thesis, we tackle this problem for both RGB and multispectral images. First, for RGB images we extend a moments based method in several ways: firstly by replacing the standard expectation value, the mean, considering moments that are based on a Minkowski p-norm; and then secondly by going over to a float value for the parameter p and carrying out a nonlinear optimization on this parameter; and finally by considering a different expectation value, generated by using the geometric mean. We show that these strategies can drive down the median and maximum error of illuminant estimates. And then for multispectral images, we formulate a multiple-illuminants estimation problem as a Conditional Random Field (CRF) optimization task over local estimations. We then improve local illuminant estimation by incorporating spatial information in each local patch.




Color Constancy


Book Description

A human observer is able to recognize the color of objects irrespective of the light used to illuminate them. This is called color constancy. A digital camera uses a sensor to measure the reflected light, meaning that the measured color at each pixel varies according to the color of the illuminant. Therefore, the resulting colors may not be the same as the colors that were perceived by the observer. Obtaining color constant descriptors from image pixels is not only important for digital photography, but also valuable for computer vision, color-based automatic object recognition, and color image processing in general. This book provides a comprehensive introduction to the field of color constancy, describing all the major color constancy algorithms, as well as presenting cutting edge research in the area of color image processing. Beginning with an in-depth look at the human visual system, Ebner goes on to: examine the theory of color image formation, color reproduction and different color spaces; discuss algorithms for color constancy under both uniform and non-uniform illuminants; describe methods for shadow removal and shadow attenuation in digital images; evaluate the various algorithms for object recognition and color constancy and compare this to data obtained from experimental psychology; set out the different algorithms as pseudo code in an appendix at the end of the book. Color Constancy is an ideal reference for practising engineers, computer scientists and researchers working in the area of digital color image processing. It may also be useful for biologists or scientists in general who are interested in computational theories of the visual brain and bio-inspired engineering systems.




Digital Color Image Processing


Book Description

An introduction to color in three-dimensional image processing and the emerging area of multi-spectral image processing The importance of color information in digital image processing is greater than ever. However, the transition from scalar to vector-valued image functions has not yet been generally covered in most textbooks. Now, Digital Color Image Processing fills this pressing need with a detailed introduction to this important topic. In four comprehensive sections, this book covers: The fundamentals and requirements for color image processing from a vector-valued viewpoint Techniques for preprocessing color images Three-dimensional scene analysis using color information, as well as the emerging area of multi-spectral imaging Applications of color image processing, presented via the examination of two case studies In addition to introducing readers to important new technologies in the field, Digital Color Image Processing also contains novel topics such as: techniques for improving three-dimensional reconstruction, three-dimensional computer vision, and emerging areas of safety and security applications in luggage inspection and video surveillance of high-security facilities. Complete with full-color illustrations and two applications chapters, Digital Color Image Processing is the only book that covers the breadth of the subject under one convenient cover. It is written at a level that is accessible for first- and second-year graduate students in electrical and computer engineering and computer science courses, and that is also appropriate for researchers who wish to extend their knowledge in the area of color image processing.




Computer Vision -- ECCV 2014


Book Description

The seven-volume set comprising LNCS volumes 8689-8695 constitutes the refereed proceedings of the 13th European Conference on Computer Vision, ECCV 2014, held in Zurich, Switzerland, in September 2014. The 363 revised papers presented were carefully reviewed and selected from 1444 submissions. The papers are organized in topical sections on tracking and activity recognition; recognition; learning and inference; structure from motion and feature matching; computational photography and low-level vision; vision; segmentation and saliency; context and 3D scenes; motion and 3D scene analysis; and poster sessions.




Computational Color Technology


Book Description

Henry Kang provides the fundamental color principles and mathematical tools to prepare the reader for a new era of color reproduction, and for subsequent applications in multispectral imaging, medical imaging, remote sensing, and machine vision. This book is intended to bridge the gap between color science and computational color technology, putting color adaptation, color constancy, color transforms, color display, and color rendition in the domain of vector-matrix representations and theories. Computational Color Technology deals with color digital images on the spectral level using vector-matrix representations so that the reader can learn to process digital color images via linear algebra and matrix theory.




Computational Color Imaging


Book Description

This book constitutes the refereed proceedings of the 4th Computational Color Imaging Workshop, CCIW 2013, held in Chiba, Japan, in March 2013. The 21 revised full papers, presented together with 4 invited papers, were carefully reviewed and selected from numerous submissions. The papers are organized in topical sections on color image perception; color combination; multi-spectral image analysis and rendering; color image detection and classification; color image features; and color image filtering and enhancement.




Acquisition and Reproduction of Color Images


Book Description

The goal of the work reported in this dissertation is to develop methods for the acquisition and reproduction of high quality digital color images. To reach this goal it is necessary to understand and control the way in which the different devices involved in the entire color imaging chain treat colors. Therefore we addressed the problem of colorimetric characterization of scanners and printers, providing efficient and colorimetrically accurate means of conversion between a device-independent color space such as the CIELAB space, and the device-dependent color spaces of a scanner and a printer.




Image and Signal Processing


Book Description

This book constitutes the refereed proceedings of the 5th International Conference on Image and Signal Processing, ICISP 2012, held in Agadir, Morocco, in June 2012. The 75 revised full papers presented were carefully reviewed and selected from 158 submissions. The contributions are grouped into the following topical sections: multi/hyperspectral imaging; image itering and coding; signal processing; biometric; watermarking and texture; segmentation and retieval; image processing; pattern recognition.




Color Imaging


Book Description

This book provides the reader with an understanding of what color is, where color comes from, and how color can be used correctly in many different applications. The authors first treat the physics of light and its interaction with matter at the atomic level, so that the origins of color can be appreciated. The intimate relationship between energy levels, orbital states, and electromagnetic waves helps to explain why diamonds shimmer, rubies are red, and the feathers of the Blue Jay are blue. Then, color theory is explained from its origin to the current state of the art, including image capture and display as well as the practical use of color in disciplines such as computer graphics, computer vision, photography, and film.




Colour Image Science


Book Description

The scope and importance of colour image science has grown rapidly in recent years. In parallel with the proliferation of consumer imaging products, the capabilities of colour displays, printers and digital cameras increase. New challenges for colour image science are emerging as cross-media image reproduction is applied in Internet and multimedia displays, motion pictures, digital television and augmented-reality systems. Colour Image Science takes an interdisciplinary approach, combining aspects of human vision with colour image capture, processing and reproduction: * Colour Vision - How we see and remember colours * Multispectral Imaging - Capturing and storing images in more than 3 channels * Image Processing - Correcting image colours and accessing databasess * Gamut Mapping - How to render colours in cross-media image reproduction * Image Quality - Metrics and methods for assessing images Colour Image Science will appeal to a wide readership, including scientists and engineers involved in the research and development of colour imaging products. It will also be a valuable reference text for post-graduate students in computer science, digital imaging and multimedia programmes.