Image Transformations and Printing of Plaster Layers in Spiral Growth Manufacturing

Spiral growth manufacturing (SGM) is a high speed rapid manufacturing technique in which objects are built up, layer by layer, by simultaneously depositing, levelling and selectively consolidating thin powder layers onto a rotating build platform. The size and position of the jetted droplets are mapped by the position and greyscale level of pixels within an 8 bit greyscale bitmap image. This paper reports on the development of software in which mathematical algorithms apply geometric transformations to images in preparation for printing onto a rotating substrate. In support of this work, dimensional accuracy measurements of printed images and methods to correct radial print density variations are reported. The accuracy of printed images were found to be within ±0.2mm of their predicted size. The experimental work is briefly extended to the direct printing of plaster layers, formed by mixing two reactive ink solutions.Mechanical Engineerin

Backward Diffusion Methods for Digital Halftoning

We examine using discrete backward diffusion to produce digital halftones. The noise introduced by the discrete approximation to backwards diffusion forces the intensity away from uniform values, so that rounding each pixel to black or white can produce a pleasing halftone. We formulate our method by considering the Human Visual System norm and approximating the inverse of the blurring operator. We also investigate several possible mobility functions for use in a nonlinear backward diffusion equation for higher quality results

North Tyneside Printing Sector Training Needs Analysis

The printing sector in this region has a proportionately low level of employment compared to the UK as a whole. North Tyneside provides the location for some 36 print-based firms, which account for only 11% of Tyne & Wear’s total print employment. However, this survey indicates that the official data significantly under-estimates the employment size of the sector in North Tyneside

A Hybrid Model Approach for Achieving the Highest Level of Matching Between the “Print and Original” in the Sheet-Fed Offset Pr

This study was designed to explore an optimized hybrid system through dual measurement approach of contrast measurement method and CIE L*a*b* measurement method to arrive a logical interface for achieving the highest matching between the print and original in sheet fed offset printing process. The work was started with the detailed study of contrast measurement, CIE L*a*b* measurement method, visual and computational intelligence based assessment and control. The master was designed in such a way that value of density and other values can be measured easily in effective way. X-Rite eXact instrument is used for capturing the readings, the 10 standard observers were selected initially by manual method and finally by using on line Fransworth-Munsell 100 Hue Colour Vision Test and visual assessments and judgement were done on X-Rite’s Macbeth Lighting Booth and their visual assessments are recorded, analyzed and represented. All the parameters like Paper, Ink, Measuring Conditions and Measuring Instruments etc. were maintained in compliance with ISO specifications. After the analysis of data, the study reached to the following main conclusion i.e. It is observed that almost in all the cases, preference of the Standard Observers are for Delta E Value leading to the higher contrast value instead of Minimum Delta E with less contrast value. Therefore the dual approach of “Hybrid System” will help us to arrive at the most convincing, measurable and perceptually acceptable print result which will be the highest (closest) match to the original by clubbing the best of “CIE Lab, Contrast Method and Standard Observers Visual Perception” as there are positives and negatives in all these three when one approaches individually. The objective of this paper was to develop a dual measurement approach of CIE Lab & Contrast to arrive at a logical inference for the highest level of matching between the original and print in the sheet fed offset printing

Reading in the presence of macular disease: a mini-review.

PurposeReading is vital to full participation in modern society. To millions of people suffering from macular disease that results in a central scotoma, reading is difficult and inefficient, rendering reading as the primary goal for most patients seeking low vision rehabilitation. The goals of this review paper are to summarize the dependence of reading speed on several key visual and typographical factors and the current methods or technologies for improving reading performance for people with macular disease.Important findingsIn general, reading speed for people with macular disease depends on print size, text contrast, size of the visual span, temporal processing of letters and oculomotor control. Attempts at improving reading speed by reducing the crowding effect between letters, words or lines; or optimizing properties of typeface such as the presence of serifs or stroke-width thickness proved to be futile, with any improvement being modest at best. Currently, the most promising method to improve reading speed for people with macular disease is training, including perceptual learning or oculomotor training.SummaryThe limitation on reading speed for people with macular disease is likely to be multi-factorial. Future studies should try to understand how different factors interact to limit reading speed, and whether different methods could be combined to produce a much greater benefit

Investigation into the capturing, manipulating, calibrating and outputting of black and white images on a Xerox Docutech

It is the purpose of this investigation to determine whether or not the output quality of black and white images on a Xerox Docutech can be enhanced. The Docutech is a black and white digital printing device. In times of a growing demand for on-demand printing and publishing, the Docutech not only has to reproduce text and graphics properly but also has to cope with the increasing task of rendering images. Although there are multiple options to improve the output quality, this project focuses on the impact of image capturing on the output. As a result of this investigation, a user\u27s manual should help to achieve satisfying reproductions on the Docutech. The project goals are reached by extensive testing and a careful evaluation of the experiments by visual, densitometric and statistical means. Prior to any testing and as a prerequisite for the project, the print characteristic of the Docutech is determined. With stable printing conditions as a starting point, the impact of the scanning process is investigated. For this purpose, four different scanners ranging from flatbed, desktop devices to high-end scanning systems are used to capture two test images. Those images are manipulated within this process step to improve the rendering quality of the printed output. The printed output is analyzed finally by statistical means to base the perceived quality differences on the objective judgement of a larger audience of observers. Focusing on the results of this evaluation process, one will find that the output quality can be enhanced. Not only are adjustments found which increase the perceived qualify of the printed result but also is insight gained into the printing process and its limitations. There is no doubt that the Docutech has its restrictions but its low cost and low quality image is not justified. It is possible to improve the output quality of black and white reproductions by applying the basic rules of image reproduction. Thus, utilizing the capabilities of this digital printing device efficiently, one can achieve satisfying output quality

Interactions between competition and consumer policy

This paper discusses complementarities and tensions between competition policies and consumer protection policies. The paper argues that markets will often supply adequate customer protection without the need for extra public intervention. Special areas where intervention might be needed are discussed, including the need to combat deceptive marketing and the need to provide additional market transparency (about both headline prices and shrouded product attributes). A few instances are presented of how more intense competition can worsen the outcomes for (some) consumers. Situations in which poorly designed consumer policies can harm consumers are discussed, including how they can be used to protect incumbent suppliers, how they can relax competition between oligopolists, how they can reduce consumer choice, how they can focus on one aspect of market performance at the expense of others, and how they can lead consumers to take insufficient care in the market.Competition policy; consumer protection; fraud; market transparency; add-on pricing

A review and evaluation of the Langley Research Center's Scientific and Technical Information Program: Results of phase 6: The technical report. A survey and analysis

Current practice and usage using selected technical reports; literature relative to the sequential, language, and presentation components of technical reports; and NASA technical report publications standards are discussed. The effctiveness of the technical report as a product for information dissemination is considered

An investigation of solid ink density variation as determined by the acceptability of overprints in process color printing

In order to establish limits which are representative of the allowable variation in solid ink density (SID) of the single process colors, as determined by the allowable variability of their overprints, a study was conducted utilizing fourteen (14) experienced color observers selected from printing companies in the Greater Rochester area. Printed color patches, at the 70% tint level of cyan, magenta, yellow, red (M+Y) , green (Y+C) , blue (M+C) and three-color overprints (Y+M+C) , were shown to observers, individually. In each group, the observer was asked to accept or reject the patch when compared to the reference standard in that group. The solid ink density of the process color or colors, which created the patch, were measured to determine the allowable variation in SID for the single colors, two and three-color over prints . The findings indicate that there is greater allow able variation when comparing single colors alone than when comparing their overprints. The standard deviations (S), ranges (R) and (R) average ranges of the allow able variation in SID for the colors utilized were: (See Thesis for Table). These findings and others would indicate that present standards, usually assigned to good quality color printing, such as -0.05, are unrealistic and unnecessary. The ranges allowed by these experienced color observers were as much as 0.42. Other significant findings show that magenta-reds are preferred to yellow-reds and that overall, increases in the magenta solid ink density were allowed more than increases in the cyan SID. There is conclusive evidence to show that these observers accepted greater variation in lightness than in hue and therefore would not accept as much hue change as lightness change. There is further evidence to indicate that it is important to monitor the hue change in the three-color overprints and near neutral colors, since these observers failed to accept comparatively small changes in SID in this region. It is, therefore, appropriate that the pressman vary SID on the press to maintain consistency in the overprints. In conclusion, it may be stated that densitometric values have been established which represent the allowable variation in SID of the single colors. These values are representative of the levels of the process colors on the press and could be applied towards a more effective method of controlling process color printing at the press