Digital Color Imaging
TL;DR: A survey of color imaging can be found in this article, where the fundamental concepts of color perception and measurement are first presented us-ing vector-space notation and terminology, along with common mathematical models used for representing these devices.
Abstract: This paper surveys current technology and research in the area of digital color imaging. In order to establish the background and lay down terminology, fundamental concepts of color perception and measurement are first presented us-ing vector-space notation and terminology. Present-day color recording and reproduction systems are reviewed along with the common mathematical models used for representing these devices. Algorithms for processing color images for display and communication are surveyed, and a forecast of research trends is attempted. An extensive bibliography is provided.
Citations
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TL;DR: This work demonstrates a convenient, versatile approach to dynamically fine-tuning emission in the full colour range from a new class of core-shell upconversion nanocrystals by adjusting the pulse width of infrared laser beams and suggests that the unprecedented colour tunability from these nanocry crystals is governed by a non-steady-state upconverting process.
Abstract: Developing light-harvesting materials with tunable emission colours has always been at the forefront of colour display technologies. The variation in materials composition, phase and structure can provide a useful tool for producing a wide range of emission colours, but controlling the colour gamut in a material with a fixed composition remains a daunting challenge. Here, we demonstrate a convenient, versatile approach to dynamically fine-tuning emission in the full colour range from a new class of core-shell upconversion nanocrystals by adjusting the pulse width of infrared laser beams. Our mechanistic investigations suggest that the unprecedented colour tunability from these nanocrystals is governed by a non-steady-state upconversion process. These findings provide keen insights into controlling energy transfer in out-of-equilibrium optical processes, while offering the possibility for the construction of true three-dimensional, full-colour display systems with high spatial resolution and locally addressable colour gamut.
777 citations
TL;DR: This article presents an overview of existing map processing techniques, bringing together the past and current research efforts in this interdisciplinary field, to characterize the advances that have been made, and to identify future research directions and opportunities.
Abstract: Maps depict natural and human-induced changes on earth at a fine resolution for large areas and over long periods of time. In addition, maps—especially historical maps—are often the only information source about the earth as surveyed using geodetic techniques. In order to preserve these unique documents, increasing numbers of digital map archives have been established, driven by advances in software and hardware technologies. Since the early 1980s, researchers from a variety of disciplines, including computer science and geography, have been working on computational methods for the extraction and recognition of geographic features from archived images of maps (digital map processing). The typical result from map processing is geographic information that can be used in spatial and spatiotemporal analyses in a Geographic Information System environment, which benefits numerous research fields in the spatial, social, environmental, and health sciences. However, map processing literature is spread across a broad range of disciplines in which maps are included as a special type of image. This article presents an overview of existing map processing techniques, with the goal of bringing together the past and current research efforts in this interdisciplinary field, to characterize the advances that have been made, and to identify future research directions and opportunities.
674 citations
TL;DR: The proposed demosaicing algorithm estimates missing pixels by interpolating in the direction with fewer color artifacts, and the aliasing problem is addressed by applying filterbank techniques to 2-D directional interpolation.
Abstract: A cost-effective digital camera uses a single-image sensor, applying alternating patterns of red, green, and blue color filters to each pixel location. A way to reconstruct a full three-color representation of color images by estimating the missing pixel components in each color plane is called a demosaicing algorithm. This paper presents three inherent problems often associated with demosaicing algorithms that incorporate two-dimensional (2-D) directional interpolation: misguidance color artifacts, interpolation color artifacts, and aliasing. The level of misguidance color artifacts present in two images can be compared using metric neighborhood modeling. The proposed demosaicing algorithm estimates missing pixels by interpolating in the direction with fewer color artifacts. The aliasing problem is addressed by applying filterbank techniques to 2-D directional interpolation. The interpolation artifacts are reduced using a nonlinear iterative procedure. Experimental results using digital images confirm the effectiveness of this approach.
462 citations
TL;DR: An overview of the image processing pipeline is presented, first from a signal processing perspective and later from an implementation perspective, along with the tradeoffs involved.
Abstract: Digital still color cameras (DSCs) have gained significant popularity in recent years, with projected sales in the order of 44 million units by the year 2005. Such an explosive demand calls for an understanding of the processing involved and the implementation issues, bearing in mind the otherwise difficult problems these cameras solve. This article presents an overview of the image processing pipeline, first from a signal processing perspective and later from an implementation perspective, along with the tradeoffs involved.
368 citations
TL;DR: The proposed fully automated vector technique can be easily implemented in either hardware or software; and incorporated in any existing microarray image analysis and gene expression tool.
Abstract: Vector processing operations use essential spectral and spatial information to remove noise and localize microarray spots. The proposed fully automated vector technique can be easily implemented in either hardware or software; and incorporated in any existing microarray image analysis and gene expression tool.
348 citations
References
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Book•
01 Jan 1970
TL;DR: A shopping cart control system for preventing the theft of shopping carts in which a track mounted on the ground and extends from a store to the automobile parking area.
Abstract: A shopping cart control system for preventing the theft of shopping carts in which a track mounted on the ground and extends from a store to the automobile parking area. The shopping cart is connected by a chain to a member slidably mounted in the track, but not removable therefrom whereby the shopping cart can only travel along a defined path. The over-all concept comprehends an attachment that lends itself to being mounted on shopping carts currently in use.
126 citations
TL;DR: An extension of the most promising measure, based on linearized CIELAB space, is proposed to obtain a new figure of merit that has a high degree of perceptual relevance and also accounts for the varying noise performance of different filters.
Abstract: In the design and evaluation of color scanners and cameras, it is useful to have a single figure of merit that closely agrees with perceived color accuracy. In the past, several measures of goodness for color scanning filters have been proposed to fulfil such a requirement. Most of the proposed measures have had shortcomings in that they are either based on error metrics in color spaces that are not perceptually uniform, or in that they do not take into account the effects of measurement noise. An extension of the most promising measure, based on linearized CIELAB space, is proposed to obtain a new figure of merit that has a high degree of perceptual relevance and also accounts for the varying noise performance of different filters. The paper also provides a common framework for the different figures of merit and a comprehensive comparison of their computational complexity and reliability.
126 citations
TL;DR: A multizone color model is described, which has nonlinear receptor gain control, two postreceptor opponent-colors processing stages, and neural compression late in the visual pathway.
Abstract: A multizone color model is described. It has nonlinear receptor gain control, two postreceptor opponent-colors processing stages, and neural compression late in the visual pathway. It is assumed that gain control can be activated by receptor responses from a test light itself (self-adaptation) and (or) by receptor responses from other adapting fields. Apparent brightnesses and visual discriminations are mediated by the first processing stage, and apparent hues and saturations are mediated by the second stage. The model accounts for a wide range of data, including nonlinear hue shifts in the color solid, various apparent brightness effects, visual discriminations for achromatic and chromatic lights under various adaptation conditions, and effects of chromatic adaptation on color appearances.
124 citations
TL;DR: An extension of the CIE 1976 (L*, a*, b*) color space, referred to as the RLAB color space as discussed by the authors, is described for applications in color reproduction, which incorporates a more accurate model of chromatic adaptation, capability to distinguish between the modes of appearance of reflective and self-luminous stimuli, and adjustments to account for changes in surround.
Abstract: An extension of the CIE 1976 (L*, a*, b*) color space, CIELAB is described for applications in color reproduction. This extension incorporates a more accurate model of chromatic adaptation, capability to distinguish between the modes of appearance of reflective and self-luminous stimuli, and adjustments to account for changes in surround. The extension of CIELAB is referred to as the RLAB color space. This color space can be used for calculating metrics of lightness, chroma, hue, and color difference. It can also be used to determine the required colors for reproduction across changes in media and viewing conditions. A pilot experiment testing the RLAB model for cross-media color reproduction is also described.
115 citations
TL;DR: In this paper, Wyszecki described radiometric functions as composed of two components, a fundamental color-stimulus function and a metameric black function, and discussed procedures for accomplishing the decomposition or resolution of any visual stimulus into these components.
Abstract: In 1953, Wyszecki described radiometric functions as composed of two components--a fundamental color-stimulus function and a metameric black function. The present paper discusses procedures for accomplishing the decomposition or resolution of any visual stimulus into these components. These methods rest on the fact that the color-stimulus space is a space of three dimensions and the metameric black space is orthogonal to it. Introduced and given specific attention here is the particular procedure wherein the stimulus-energy vector is premultiplied by A(A'A)-1A', A being any matrix of experimentally established color-mixture data with three linearly independent columns (primaries). This computation provides the fundamental metamer (as we shall call it) of the visual stimulus being analyzed. The difference between the stimulus-energy distribution and the fundamental metameric function provides the metameric black function. Examples of both types of functions are given and discussed.
114 citations