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

Applications of remote sensing, volume 3

The author has identified the following significant results. Of the four change detection techniques (post classification comparison, delta data, spectral/temporal, and layered spectral temporal), the post classification comparison was selected for further development. This was based upon test performances of the four change detection method, straightforwardness of the procedures, and the output products desired. A standardized modified, supervised classification procedure for analyzing the Texas coastal zone data was compiled. This procedure was developed in order that all quadrangles in the study are would be classified using similar analysis techniques to allow for meaningful comparisons and evaluations of the classifications

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

Characterization of color, gloss and mechanical performance of 3D printed structures

The demand for customized products is on a rise. As such, there is a great need for methods to efficiently satisfy this need for customization. Rapid prototyping, also known as 3D printing, is a technology that enables economic production of customized low volume products and enables expedited product development cycles. Given the importance of color as a means to differentiate products generated through 3D printing processes, accurate color reproduction is essential for broad market acceptance. Color reproduction in 2D document printing is itself a complex science; achieving similar results in 3D printing will require significant research. This research work explores the various factors that affect accurate color reproduction in rapid prototyping. More specifically, it studies the effect of process parameters and post-processing techniques on the color reproduction achieved in powder based layer deposition process with a selective binder delivery enabled by an ink-jet print head. A systematic study of a subset of these factors was conducted using a ZCorp Z510 3D printer. The process parameters that were included in the study were color, hue, coverage, layer thickness, and binder saturation. The post-processing technique focused on the use of an infiltrant, which is commonly used to increase the mechanical strength of the printed 3D structure. The response variables of interest for this study included color response, gloss and mechanical strength. A full factorial experiment was designed in order to characterize the effect. Gloss, which contributes to the visual perception, was studied as a qualitative response. Of particular interest was the effect of process parameters and the type of post processing on the tensile strength of the specimen to identify trade-offs between quality of color reproduction and the mechanical strength required for structural integrity. Analysis of the experimental data indicates that the standard process settings, on average, generate samples that have greater color lightness and lower chroma, representing an opportunity for improvement. In addition, layer thickness was found to have a significant effect on the tensile strength as well. The process of infiltration improved both the color reproduction and mechanical properties of the 3D printed samples. The choice of infiltrant did not have a significant effect on the color reproduction but had a significant effect on the tensile strength of the part. In this research, the effect of layer thickness on color reproduction in ink jet based 3D printing has been studied for the first time. Also, adding to the body of current research, the interaction effects of the various factors have been studied. The research intends to serve as a platform to enable color scientists to collaborate with rapid prototyping experts towards achieving full selective color throughout 3D printing in the future

Evaluation of Comparative Repair Methods for Stone

Stone masonry, once popular in 19th and early 20th century America, was gradually replaced by concrete and other modern building materials. Many Pennsylvania quarries produced prized local stone such as Pennsylvania Blue Marble, Hummelstown Brownstone, and Chester County Serpentine, all no longer quarried. These materials were used to construct numerous historically significant architecture in the Mid-Atlantic Region. While material authenticity is one of the guiding philosophies for conservation design, oftentimes compromises must be made for many reasons—cost, availability, compatibility with other materials or structure, schedule, skilled labor, aesthetics and an important one which will be the focus of this thesis—durability. Using serpentine as a model, this paper explores alternative methods of non-in-kind repair for buildings constructed with stones no longer quarried in the United States. Two methods are evaluated in detail: Creating a new face or patching using Lithomex, a composite repair material applied directly onto a substrate such as stone or brick. Creating a new face or unit replacement with an available stone such as sandstone, colored with Colorwash Stain, a potassium silicate mineral stain for masonry. An evaluation of repair durability is assessed by comparing surface erosion and color change before and after accelerated weathering. Profile change (profilometry) is assessed through digital models of the samples created with a structural light 3D scanner and color change is analyzed by comparative spectrophotometry. Three case studies of past serpentine repair act as additional discussion of repair methods not evaluated through testing

Analysis of image noise in multispectral color acquisition

The design of a system for multispectral image capture will be influenced by the imaging application, such as image archiving, vision research, illuminant modification or improved (trichromatic) color reproduction. A key aspect of the system performance is the effect of noise, or error, when acquiring multiple color image records and processing of the data. This research provides an analysis that allows the prediction of the image-noise characteristics of systems for the capture of multispectral images. The effects of both detector noise and image processing quantization on the color information are considered, as is the correlation between the errors in the component signals. The above multivariate error-propagation analysis is then applied to an actual prototype system. Sources of image noise in both digital camera and image processing are related to colorimetric errors. Recommendations for detector characteristics and image processing for future systems are then discussed

An entrepreneurial framework for deciding on the implementation of large format digital printing internationally

This study focuses on entrepreneurs within the SME sector using large format digital printing (LFDP) because of the changes in technology that influences the decisionmaking processes of the entrepreneur in the purchasing of a new LFDP. These fast changes are likely to continue and can cause technologies to become obsolete overnight. The entrepreneurs within the LFDP industry find themselves in the midst of these fast changes and are faced with a dilemma. On the one hand, they need to make sure that the technology used produces consistent and quality products. On the other hand, the entrepreneur needs to ensure an optimal return on investments. From the literature and the findings of the study, the researcher recommends a change to an existing model on a consultant involvement purchase of high technology products, which is then adapted to integrate resource-forecasting areas together with timing and type of information required as well as external environment scanning. The existing model’s focus is on the individual’s ability to make decisions based on their own knowledge. However, by integrating technology forecasting components, and scanning the business environment and resource forecasting needed the decision-maker will be better equipped to make decisions that also takes into account the external environment. This will also allow them to plan and manage growth in a systematic way. Therefore the proposed model takes into account individual capabilities and technology forecasting components that can facilitate the decision-making process. The adapted model on decision-making clearly delineates that the combination of entrepreneurial qualities and technology forecasting techniques in the LFDP industry will ultimately assist the entrepreneur on various levels in deciding on a new LFDP

Agricultural scene understanding

The author has identified the following significant results. The LACIE field measurement data were radiometrically calibrated. Calibration enabled valid comparisons of measurements from different dates, sensors, and/or locations. Thermal band canopy results included: (1) Wind velocity had a significant influence on the overhead radiance temperature and the effect was quantized. Biomass and soil temperatures, temperature gradient, and canopy geometry were altered. (2) Temperature gradient was a function of wind velocity. (3) Temperature gradient of the wheat canopy was relatively constant during the day. (4) The laser technique provided good quality geometric characterization

Test targets 5.0: A Collaborative effort exploring the use of scientific methods for color imaging and process control

Test Targets is about scholarship that intimately involves faculty and students in the process of writing and publishing. It is a collection if research papers that require collaborative effort over a time span of three academic quarters. Initially, students learned metrology, color management system, and the use of test targets for device optimization and process control. As time goes by, students are encouraged to identify research topics, formulate methodologies, and carry out experiments and data analyses in order to have specific findings. - p.