Color CRT Research Articles

ID Asks/Kenneth Werner

ID Asks/Kenneth Werner

ONE APPROACH TO CAI-EFL PROBLEMS IN JAPAN

Some current topics related to CAI-EFL field in Japan are reviewed with emphasis on the achievements of the TELP (Tokai English Language Program)-CAI project, which developed a stand-alone microcomputer system in 1979 and another CAI-EFL system in 1984, along with abundant courseware. The latest system, called TELP-CAI System III, is described. It is composed of a personal computer keyboard, a color CRT, a cassette tape deck, a floppy disc drive unit, and a tailor-made interface unit to integrate all these devices. Including some of its features, like the menu-format authoring system, the discussion extends to on-going improvements for continued development of this system.

Real-world stimuli show perceived hue shifts in the peripheral visual field

Certain hues undergo shifts in their appearance when they are viewed by the peripheral retina. This has often been shown on a 3-primary color CRT monitor. To investigate the possible role of metamerism, we replicated our peripheral color matching experiments using Munsell paper stimuli viewed under real and simulated daylight (using a 3-primary projection system). Using stimuli of constant value and chroma (7/4), observers adjusted the hue of a 3 deg target presented 18 deg nasally, until it matched a 1 deg target presented 1 deg nasally. The magnitude and pattern of measured hue shifts were similar to those measured using CRT stimuli. We conclude that the perceived hue shifts that have previously been reported in the peripheral retina are independent of the nature of the stimulus and of the illuminant.

DISPLAY QUALITY OF DIFFERENT MONITORS IN FELINE DIGITAL RADIOGRAPHY

In human medical imaging, the performance of the monitor used for image reporting has a substantial impact on the diagnostic performance of the entire digital system. Our purpose was to compare the display quality of different monitors used in veterinary practice. Two medical-grade gray scale monitors (one cathode-ray tube [CRT], one liquid crystal display [LCD]) and two standard consumer-grade color monitors (one CRT, one LCD) were compared in the ability to display anatomic structures in cats. Radiographs of the stifle joint and the thorax of 30 normal domestic shorthair cats were acquired by use of a storage phosphor system. Two anatomic features of the stifle joint and five anatomic structures of the thorax were evaluated. The two medical-grade monitors had superior display quality compared with standard PC monitors. No differences were seen between the monochrome monitors. In comparison with the color CRT, the ratings of the color LCD were significantly worse. The ranking order was uniform for both the region and the criteria investigated. Differences in monitor luminance, bit depth, and screen size were presumed to be the reasons for the observed varying performance. The observed differences between monitors place an emphasis on the need for guidelines defining minimum requirements for the acceptance of monitors and for quality control in veterinary radiography.

Light scattering in artificial fog and simulated with light scattering filter

Disability glare, affecting e.g. road safety at night, may result either from intraocular light scattering or from external conditions such as fog. Measurements were made of light scattering in fog and compared with intraocular straylight data for normal eyes and eyes with simulated cataract. All measurements were made with a direct compensation flicker method. To estimate light scattering levels in fog, straylight measurements were carried in a fog chamber for different densities of fog. Density was characterized by the meteorological term visibility V and ranged from 7 to 25. Test distance for measurements in the fog was constant at 5 m. Cataract eye conditions were simulated by placing a light scattering polymer dispersed liquid crystal (PDLC) filter with scatterers of submicron size in front of the normal eye. All measurements were made using each of three broad-band color stimuli - red, green and blue (produced either with LEDs or a color CRT monitor). Differences were found in both the level and the spectral characteristics of scattering under the different conditions. The measured values of the straylight parameter, s, in artificial fog showed no noticeable spectral dependence at any visibility range. Increasing the visibility range caused an exponential decrease in the straylight. Intraocular straylight measured with the clear eye showed an increase at the red and blue ends of the spectrum as compared to the green. Straylight measured using PDLC plates with different transparency levels showed a spectral dependence which decreased with wavelength. The scattering introduced by the PDLC plate therefore failed to give a valid simulation of cataract and fog conditions for polychromatic stimuli, due to its erroneous spectral dependence.

A study on spot distortion for an in‐line self‐converging system for color CRTs

Abstract— The spot distortion at the screen periphery of an in‐line self‐converging CRT is formulated by considering four factors; (a) oblique incidence of the beam at the screen periphery, (b) increased path length of the beam, (c) beam compression due to the deflection, and (d) the astigmatism due to the deflection field. The analytic spot size calculated with the formulas agrees well with measurement, though the effects of a particular gun system, spherical aberration, and space‐charge repulsion are not taken into consideration in the formulas while assuming an ideal deflection field. The analytic formulas enable easy evaluation of spot distortion at the screen periphery because they give an intuitive understanding of beam behavior in the in‐line self‐converging system. In addition to the derivation of the formulas, “transposed scanning” is analyzed with the use of the formulas for one of the ways to optimize the spot distortion at the screen periphery.

Influence of random-dot textures on perception of suprathreshold color differences

We have analyzed the way in which simulated textures made of random dots influence visual suprathreshold color tolerances. We considered 32 textures created by a systematic variation of the following variables: size, number, and color of the dots. Each texture was mapped on the five centers recommended by the International Commission on Illumination (CIE) in 1978 [Color Res. Appl.3, 149 (1978)]. A panel of five experienced observers determined the experimental tolerances using a CRT color monitor by the method of adjustment. At our observation distance, neither small differences in dot size (1 or 4 pixels) nor sparse number of dots (less than 20% of the surface of the sample) changed the tolerances found for homogeneous samples. For the textures that led to statistically significant differences with respect to homogeneous samples, the parametric factors of CIEDE2000 and CIE94 color-difference formulas were fitted. These simulated textures consistently reduced the color difference perceived in a pair or, equivalently, increased the tolerances, mainly (but not only) lightness tolerance. The results demonstrate that it is not simple to provide a unique set of parametric factors for all the potential textures.

Development of CRT’s corner cutting repair systems

CRT Corner cutting tube is considered as a definitive reject and will be sent to reclaim at all times. It caused lots of material loss. In this paper, a novel technology used to save CRTs corner cutting tube is presented firstly. A set of repair system has been successfully developed to repair CRTs corner cutting tube. Then, the process technology for corner cutting repair has been excogitated by empirical studies. Finally, the correlative performances of repaired tube are evaluated. The experimental results show that the quality of repaired tube has no difference with that of normal product. The repair yield has reached above 97 percent. This new technology has contributed to improving the production yield, reducing the material consumption and decreasing the cost of color CRT production.

Fabrication of brightness optimizer for CRT color monitors

AbstractIn CRT monitor characterization accuracy is largely affected by the brightness setting on the monitor. At the optimum brightness level, which adjusts the offsets of RGB channels to nearly zero, CRT monitors have a simple relationship between DAC count and luminance so characterization can be achieved accurately. However, since the optimum brightness levels of CRT monitors are different from one another monitor users, have to make adjustments to the monitor themselves. In this study, a simple device named, brightness optimizer, is fabricated to determine the optimum brightness level objectively. This method uses change of curvature in tone reproduction curves plotted in log‐log scale, according to the changes of brightness level. In this article, the configuration of the brightness optimizer and the measurement processes are described. The repeatability and the accuracy in the measurement of the optimum brightness level for three different CRT monitors are also evaluated. © 2003 Wiley Periodicals, Inc. Col Res Appl, 28, 468–472, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10199

Generation mechanism and evaluation of overall raster moiré patterns on color CRTs

Abstract— An evaluation technique of overall raster moiré patterns on color CRTs is developed. The technique can simulate any of the moiré modes. Generation mechanisms of various moiré patterns are clarified using the technique. It is found that the moiré patterns, no matter how complicated, consist of four basic types: barrel, pincushion, elliptical, and hyperbolic types. The patterns are found to be sensitive to the scan line distribution. When the scan lines are curved, the pattern appearing on the upper screen is different from that on the lower screen. When the scan lines are tilted, the patterns have horizontal shifts. By observing the moiré patterns, the scan line distribution can be estimated precisely.

THE EFFECTS OF AN AREA OF AN OVERLAPPING REGION OF TWO TEXTURES AND THEIR COMPOUND OUTLINE ON TEXTURE LACINESS

Three experiments were performed to examine how the spatial arrangement of two texture squares affected the occurrence of texture laciness, which is named by Watanabe and Cavanagh (1992). When two texture squares were presented with a part of them overlapping, one square is seen through the other in front of it for some arrangement. Varied were the area of the overlapping region of the squares and the compound outline produced by the squares. Ten undergraduates rated the stimuli generated on a color CRT display according to texture laciness. The experiments showed that the rating of laciness was higher where the compound outline of the squares was easily decomposed into two squares rather than where it was not. The area of the overlapping region did not produce any difference. The results indicate that texture laciness is affected by perceptual organization of the squares in the display.

P‐16: Simulation and Analysis of Overall Raster Moire Patterns on Color CRTs

AbstractGeneration mechanisms of various moire patterns are clarified, and a simulation technique of overall raster moire patterns appearing on the color CRT screen is developed. The moire patterns are found to be sensitive to the slope and curvature of the scan lines. The technique allows to determine various CRT design parameters.

Overtraining in back‐propagation neural networks: A CRT color calibration example

A condition of overtraining a back-propagation neural network exists when excessive model degrees of freedom are used in network training. A CRT color calibration experiment was done to illustrate methods to avoid an overtrained condition in model development. Cross-validation, in which the experimental data are split into parameter-training and independent-test data sets, is advocated. © 2002 Wiley Periodicals, Inc. Col Res Appl, 27, 122–125, 2002; DOI 10.1002/col.10027

Overtraining in back‐propagation neural networks: A CRT color calibration example

AbstractA condition of overtraining a back‐propagation neural network exists when excessive model degrees of freedom are used in network training. A CRT color calibration experiment was done to illustrate methods to avoid an overtrained condition in model development. Cross‐validation, in which the experimental data are split into parameter‐training and independent‐test data sets, is advocated. © 2002 Wiley Periodicals, Inc. Col Res Appl, 27, 122–125, 2002; DOI 10.1002/col.10027

10-6 カラーCRTにおけるビームプロファイル選択によるラスタモアレの低減

10-6 カラーCRTにおけるビームプロファイル選択によるラスタモアレの低減

Real-time full-color three-dimensional display with a micromirror array

We designed, realized, and tested what is believed to be the first real-time, full-color, autostereoscopic three-dimensional (3-D) display with a micromirror array. Compared with the diffractive partial pixel architecture [Opt. Lett. 20, 1418 (1995)], this approach has certain advantages:(1) Micromirrors are reflective and thus achromatic (panchromatic) and (2) a variety of displays can be used as the image source. We used backlit transparencies to test the system and then used an ordinary color CRT to show several computer-generated full-color 3-D animations.

25.3: Optimized Phosphors for Field Emission Displays

AbstractCandescent Technologies and SONY have developed the first commercially viable, full color, high performance field emission display (FED) which combines the premium visual performance of a color CRT in a thin flat panel package. Because of the similarity between the FED and CRT electron excitation, the FED can use the conventional P22 color CRT phosphor triad. However in this paper we will show improved performance for screens based on phosphors optimized for the lower accelerating voltage of the FED (7–10 kV). Data will be presented showing screen performance in full color FED's including color gamut, white screen brightness and luminous efficacy. This data will compare optimized phosphors with the P22 color CRT phosphors. The most striking improvement has been seen for the ZnS:Ag blue phosphor where the optimized phosphor shows higher efficacy, superior color saturation, and improved maintenance of efficacy with coulombic aging when compared to the P22 blue phosphor. Factors which influence the phosphor performance will be discussed including activator and co‐activator concentration as well as phosphor crystal structure as measured by cross sectional TEM.

The feasibility of dynamic color separation: data from a 20V display prototype

Abstract— This article provides performance requirements and measurement data on dynamic‐color‐separation (DCS) displays. Implementation for a 20V prototype is described. Measurement on its electron gun and phosphor screen provides a benchmark by which requirements for the full range of color CRT displays may be extrapolated. The advantages of DCS are summarized.

Users' behavior and performance of general-purpose color CRT monitors of PACS in the wards

The hospital-wide PACS uses personal computer and general-purpose color CRT monitor as a client because many clients are demanded in the wards, but medical CRTs are too expensive; and the PACS stored and delivered endoscopic color images. Users should adjust each CRT monitor because of fewer administrators and too many clients. But the adjustment of color CRT monitors is not simple. It will be so complicated to meet the luminance characteristics, including maximum and minimum luminance and regional contrasts. We were afraid that the maladjustment of CRT caused misunderstanding in the daily practice. We should have an easy way of adjusting general-purpose CRT monitors from the recognition of CRT characteristics. In this paper, we focused on the adjustment of the contrast and brightness of color CRT monitors, and the users' behavior on this adjustment. The characteristic curves of luminance on several contrast and brightness settings were measured. The characteristic curve on the lower brightness and higher contrast seemed to be similar to the ideal curve of the medical CRT monitor. Users' settings were also similar to that according to clinical images.

Erratum

Color Research & ApplicationVolume 26, Issue 3 p. 233-233 ErratumFree Access Erratum First published: 03 April 2001 https://doi.org/10.1002/col.1020Citations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat References 6 Díaz JA, Jiménez JR, Hita E, Jiménez del Barco L. Optimizing the constant-channel chromaticity and color gamut of CRT color displays by control of brightness and contrast levels. Appl Opt 1996; 35: 1711– 1718. Citing Literature Volume26, Issue3June 2001Pages 233-233 ReferencesRelatedInformation