Michael Stokes

Bio: Michael Stokes is an academic researcher. The author has contributed to research in topics: ICC profile & Color space. The author has an hindex of 3, co-authored 5 publications receiving 517 citations.

Limitations in Communicating Color Appearance with the ICC Profile Format.

Abstract: The ICC format has been widely adopted as an industry standard for communicating color and a context has been presented for implementing and interpreting this standard. There are three major implications of the way the ICC profile format has been publicly presented for use in communicating color; user interface and application development complexity, possible quality limitations due to undefined transforms, and the possible quality degradation of business graphics. Some specific implications for peripheral vendors will also be discussed.

The History of the ICC.

Abstract: The History of the ICC In recent years hopes of resolving the chaos of color reproduction in open systems and the World Wide Web have slowly become focused on de facto industry standards. Apple Computer led an initiative starting in the spring of 1993, known as the ColorSync Consortium, to resolve this chaos. Over the next eighteen months, this initiative produced an open, cross-platform device color characterization profile format specification based on the Apple ColorSync profile format and set the groundwork for unambiguous interaction among color devices and vendors in open systems. The following year was spent transforming this informal consortium into the International Color Consortium (ICC), a formal, non-profit organization. The next eighteen months were spent establishing clear goals for the consortium and struggling with intellectual property issues. Following this effort, the last six months have seen the genesis of new work to inventory all known problems with the ICC specification, create a set of reference implementation and establish guidelines for conformance testing. If these initiatives are successful, it appears that the ICC might finally meet many of its ambitious initial goals. As founding chairperson of the ColorSync Consortium, color architect for ColorSync 2 and recent past chairperson of the ICC, I have been intimately involved in all of the developments described above. I have also been involved in other related open color standards activities. This paper represents my personal viewpoint on these developments and the ICC in general. It does not necessarily represent the official position of the International Color Consortium, Apple Computer or Hewlett-Packard Company. Introduction – Before ColorSyncTM In recent years hopes of resolving the chaos of color reproduction in open systems and the World Wide Web have slowly become focused on the de facto industry standards. It might help to understand the current status of digital color reproduction by briefly examining how this field has evolved. The field of digital color reproduction is a congruence of several much older industries merging together. Each of these industries has their individual aspects of color reproduction that have evolved within the constraints of their particular production workflows. These industries include; broadcast television, motion pictures, slide reproduction, still photography, photofinishing, computer graphics, desktop publishing, paint formulation, presentation graphics, multimedia presentation and graphic arts. Color Science has provided a scientific foundation for all of these industries with varying degrees of significance, but each industry has extended this foundation with empirical results that are specialized to its particular needs. Thus, each of these industries individually encompasses a significant body of knowledge with respect to color reproduction issues. Much has been previously written about the traditional aspects of each field, usually from an analog point of view. In addition, researchers in color science have continued to advance the scientific foundations over the last several decades quite independently from any of these industries. Unfortunately until quite recently most of these efforts have also been independent of modern computer operating systems and digital networks. This has caused significant transition problems between the traditional methods and the constraints imposed by open computing environments and in particular the World Wide Web. The advent of digital color processing applications in open systems, and in particular the World Wide Web, has forced all of these industries into working within open computing environments and with each other. This created a new technology field—digital color reproduction. This relatively new field has inherited many of the methods and standards from each of its contributing industries. This is in addition to contributions from researchers in the color science community and in combination with the constraints imposed by the various software operating systems, networks, applications and devices that compose the digital computing environment today. The tensions between the traditional industries with each other, and along with the new digital technology, have created an interesting and often conflict-filled new technical environment for digital color reproduction. Most of the current practitioners trace their experience directly to either one of the color or computer industries listed above and many claim authority in setting direction and standards in this new field. Some traditional imaging companies feel threatened by the control of color by operating system venders or other traditional imaging industries. There has been a great reluctance to open up solutions for the betterment of the end-users. This has created an amalgam of solutions for end-users, none of which have fully answered the desire to have transparent, predictable color reproduction and most of which are incompatible with each other. In particular, the current chaos in this new field can be attributed to a few companies who had control or near monopolies in a single one of the many traditional analog imaging industries. In this new digital color reproduction field, these companies are fighting to survive. These same traditional analog companies are often the most vocal opponents to open standards for digital color reproduction. This is exemplified by attacks on open standards activities without constructive counter-proposals. Some of this resistance is due to a strong business strategy based on pro-

Color spectrum management method and system for ensuring color matching between an object and its electronic image

Abstract: Color characteristics of each color of object (4) and its support are determined. Object color absorbency and brilliance are measured. Absorbency characteristics of object colorants are determined. Electronic image of object is produced and object and support color characteristics data attached. Data space in electronic image (2) is established and data inserted into data space. Data indicative of object and support color characteristics are restored from electronic image. Color characteristics (14,22) used by output device (10,18) are determined and support characteristics (12,20) used by the output device (10,18). Measuring norm is generated from indicative data for all color characteristics. Electronic image (2) is modified by applying the norm and output.

Most apparent distortion: full-reference image quality assessment and the role of strategy

Abstract: The mainstream approach to image quality assessment has centered around accurately modeling the single most relevant strategy employed by the human visual system (HVS) when judging image quality (e.g., detecting visible differences, and extracting image structure/information). In this work, we suggest that a single strategy may not be sufficient; rather, we advocate that the HVS uses multiple strategies to determine image quality. For images containing near-threshold distortions, the image is most apparent, and thus the HVS attempts to look past the image and look for the distortions (a detection-based strategy). For images containing clearly visible distortions, the distortions are most apparent, and thus the HVS attempts to look past the distortion and look for the image's subject matter (an appearance-based strategy). Here, we present a quality assessment method [most apparent distortion (MAD)], which attempts to explicitly model these two separate strategies. Local luminance and contrast masking are used to estimate detection-based perceived distortion in high-quality images, whereas changes in the local statistics of spatial-frequency components are used to estimate appearance-based perceived distortion in low-quality images. We show that a combination of these two measures can perform well in predicting subjective ratings of image quality.

VSNR: A Wavelet-Based Visual Signal-to-Noise Ratio for Natural Images

Abstract: This paper presents an efficient metric for quantifying the visual fidelity of natural images based on near-threshold and suprathreshold properties of human vision. The proposed metric, the visual signal-to-noise ratio (VSNR), operates via a two-stage approach. In the first stage, contrast thresholds for detection of distortions in the presence of natural images are computed via wavelet-based models of visual masking and visual summation in order to determine whether the distortions in the distorted image are visible. If the distortions are below the threshold of detection, the distorted image is deemed to be of perfect visual fidelity (VSNR = infin)and no further analysis is required. If the distortions are suprathreshold, a second stage is applied which operates based on the low-level visual property of perceived contrast, and the mid-level visual property of global precedence. These two properties are modeled as Euclidean distances in distortion-contrast space of a multiscale wavelet decomposition, and VSNR is computed based on a simple linear sum of these distances. The proposed VSNR metric is generally competitive with current metrics of visual fidelity; it is efficient both in terms of its low computational complexity and in terms of its low memory requirements; and it operates based on physical luminances and visual angle (rather than on digital pixel values and pixel-based dimensions) to accommodate different viewing conditions.

Billmeyer and Saltzman's Principles of Color Technology

Abstract: Defining Color. Describing Color. Measuring Color. Measuring Color Quality. Colorants. Producing Colors. Back to Principles. Appendix. Bibliography. Index.

On the removal of shadows from images

Abstract: This paper is concerned with the derivation of a progression of shadow-free image representations. First, we show that adopting certain assumptions about lights and cameras leads to a 1D, gray-scale image representation which is illuminant invariant at each image pixel. We show that as a consequence, images represented in this form are shadow-free. We then extend this 1D representation to an equivalent 2D, chromaticity representation. We show that in this 2D representation, it is possible to relight all the image pixels in the same way, effectively deriving a 2D image representation which is additionally shadow-free. Finally, we show how to recover a 3D, full color shadow-free image representation by first (with the help of the 2D representation) identifying shadow edges. We then remove shadow edges from the edge-map of the original image by edge in-painting and we propose a method to reintegrate this thresholded edge map, thus deriving the sought-after 3D shadow-free image.

Digital Image Processing: An Algorithmic Introduction Using Java

Abstract: This revised and expanded new edition of an internationally successful classic presents an accessible introduction to the key methods in digital image processing for both practitioners and teachers. Emphasis is placed on practical application, presenting precise algorithmic descriptions in an unusually high level of detail, while highlighting direct connections between the mathematical foundations and concrete implementation. The text is supported by practical examples and carefully constructed chapter-ending exercises drawn from the authors' years of teaching experience, including easily adaptable Java code and completely worked out examples. Source code, test images and additional instructor materials are also provided at an associated website. Digital Image Processingis the definitive textbook for students, researchers, and professionals in search of critical analysis and modern implementations of the most important algorithms in the field, and is also eminently suitable for self-study.