Image categorisation based on the spatiochromatic information

An imaging workflow to categorise images into business graphics and pictorial images based on spatiochromatic information is demonstrated. Studies on three computational characteristics (lightness frequency distribution, average chroma distribution, and Fourier spectrum) show that differences between business graphics and pictorial images can be discriminated mathematically. To enhance the performance of the image categorisation workflow, a multilayer perceptron neural network was designed and experimentally evaluated, and which performed with an accuracy of 95% using a database consisting of 57 randomly selected images

Digital Color Imaging

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

Contemplation of tone mapping operators in high dynamic range imaging

The technique of tone mapping has found widespread popularity in the modern era owing to its applications in the digital world. There are a considerable number of tone mapping techniques that have been developed so far. One method may be better than the other in some cases which is determined by the requirement of the user. In this paper, some of the techniques for tone mapping/tone reproduction of high dynamic range images have been contemplated. The classification of tone mapping operators has also been given. However, it has been found that these techniques lack in providing quality of service visualization of high dynamic range images. This paper has tried to highlight the drawbacks in the existing traditional methods so that the tone-mapped techniques can be enhanced

Computer mediated colour fidelity and communication

Developments in technology have meant that computercontrolled imaging devices are becoming more powerful and more affordable. Despite their increasing prevalence, computer-aided design and desktop publishing software has failed to keep pace, leading to disappointing colour reproduction across different devices. Although there has been a recent drive to incorporate colour management functionality into modern computer systems, in general this is limited in scope and fails to properly consider the way in which colours are perceived. Furthermore, differences in viewing conditions or representation severely impede the communication of colour between groups of users. The approach proposed here is to provide WYSIWYG colour across a range of imaging devices through a combination of existing device characterisation and colour appearance modeling techniques. In addition, to further facilitate colour communication, various common colour notation systems are defined by a series of mathematical mappings. This enables both the implementation of computer-based colour atlases (which have a number of practical advantages over physical specifiers) and also the interrelation of colour represented in hitherto incompatible notations. Together with the proposed solution, details are given of a computer system which has been implemented. The system was used by textile designers for a real task. Prior to undertaking this work, designers were interviewed in order to ascertain where colour played an important role in their work and where it was found to be a problem. A summary of the findings of these interviews together with a survey of existing approaches to the problems of colour fidelity and communication in colour computer systems are also given. As background to this work, the topics of colour science and colour imaging are introduced

Derivation and modelling hue uniformity and development of the IPT color space

Metric color spaces have been determined to be significantly non-uniform in the hue attribute of color appearance. Several independent sources have confirmed the non-uniformity. A data set was obtained during the course of this thesis work that contains the largest sampling of color space to date which can be used to compare models of color appearance. The data set obtained was compared to existing data sets and found to correspond closely. Lookup table methods were employed to test significant differences between data sets. A simple modeling approach was taken based on commonly understood color space models and knowledge of the visual system. Several color spaces can be derived using the simple model, and one was chosen that models hue uniformity very well and has other desirable attributes. This new color space is named IPT. Many visual data sets were plotted in the IPT color space and all show improved performance over industry standard color spaces. The IPT color space has applications in color data representation, gamut mapping, and color appearance modeling

AN APPRAISAL OF THE DEVELOPMENTS IN THE REPRODUCTION OF COLOUR IN COMPUTER PUBLISHING SYSTEMS

The plethora of coloured images that are reproduced in any printed media is facilitated through a variety of related processes that collectively constitute traditional printing techniques. The aim of this research is to appraise recent developments that have occurred within the colour prepress process. The colour prepress process involves the preparation of colour separated halftone films that are used in the production of offset lithographic printing plates. Over recent years the application of desktop publishing technology to perform many of the functions associated with the colour prepress process has raised a number of significant issues and debates. The reproduction of coloured images in the printed medium demands that certain fundamental criteria are adhered to in order to maintain professional standards of colour fidelity. Such criteria include: successful digital halftone production, the elimination of moiré patterns, and maintaining colour fidelity between the coloured original and the coloured reproduction. This research thesis shall therefore establish the principles and techniques involved in the reproduction of colour in a printed medium. It will also asses whether desktop publishing systems are able to facilitate successful professional colour reproduction by examining current debates that challenge the viability of desktop publishing solutions. Current debates concerning desktop publishing solutions are primarily concerned with assessing the value of Adobe PostScript level 2 solutions, computer interchange spaces for colour matching purposes, and rational supercell techniques that attempt to eliminate moiré patterns. The research also attempts to establish the validity of current debate findings by comparing them with statistics derived hom a questionnaire (undertaken as part of the research program) that seeks the opinions of system users on the effectiveness of their individual systems at processing and delivering acceptable colour separations

The design-by-adaptation approach to universal access: learning from videogame technology

This paper proposes an alternative approach to the design of universally accessible interfaces to that provided by formal design frameworks applied ab initio to the development of new software. This approach, design-byadaptation, involves the transfer of interface technology and/or design principles from one application domain to another, in situations where the recipient domain is similar to the host domain in terms of modelled systems, tasks and users. Using the example of interaction in 3D virtual environments, the paper explores how principles underlying the design of videogame interfaces may be applied to a broad family of visualization and analysis software which handles geographical data (virtual geographic environments, or VGEs). One of the motivations behind the current study is that VGE technology lags some way behind videogame technology in the modelling of 3D environments, and has a less-developed track record in providing the variety of interaction methods needed to undertake varied tasks in 3D virtual worlds by users with varied levels of experience. The current analysis extracted a set of interaction principles from videogames which were used to devise a set of 3D task interfaces that have been implemented in a prototype VGE for formal evaluation

Color 3D Printing: Theory, Method, and Application

Our research team proposes a colored manufacturing technology with a layer-by-layer printing process. Using digital inkjet printing in layer-by-layer printing color graphics, a further low-cost color 3D Printing (3DP) technology can be developed. It can provide an integrated way to prototype and reproduce 3D objects, from concept to design and manufacturing. Ultimately, with fast graphics printing method, it guarantees a feasible way to further promote cultural and creative products

A Paradigm for color gamut mapping of pictorial images

In this thesis, a paradigm was generated for color gamut mapping of pictorial images. This involved the development and testing of: 1.) a hue-corrected version of the CIELAB color space, 2.) an image-dependent sigmoidal-lightness-rescaling process, 3.) an image-gamut- based chromatic-compression process, and 4.) a gamut-expansion process. This gamut-mapping paradigm was tested against some gamut-mapping strategies published in the literature. Reproductions generated by gamut mapping in a hue-corrected CIELAB color space more accurately preserved the perceived hue of the original scenes compared to reproductions generated using the CIELAB color space. The results of three gamut-mapping experiments showed that the contrast-preserving nature of the sigmoidal-lightness-remapping strategy generated gamut-mapped reproductions that were better matches to the originals than reproductions generated using linear-lightness-compression functions. In addition, chromatic-scaling functions that compressed colors at a higher rate near the gamut surface and less near the achromatic axis produced better matches to the originals than algorithms that performed linear chroma compression throughout color space. A constrained gamut-expansion process, similar to the inverse of the best gamut-compression process found in this experiment, produced reproductions preferred over an expansion process utilizing unconstrained linear expansion