Color CRT Research Articles

Categorical Color-Name Regions of A Color Spacein Aperture and Surface Color Modes.

When we indicate or describe an object in everyday lives we often use a color of the object. Although there are a million of colors around us we do not use so many colors, but categorize different colors into several color names. Eleven color names; red, green, yellow, blue, brown, orange, purple, pink, white, black and gray, have been qualified as basic color categories, that are used consistently among observers and occasions. In this study we measured categorical regions in a color space determined with a categorical color naming method using these 11 basic color names. Two color-appearance modes; aperture color mode and surface color mode, were tested. We employed both a color CRT monitor and a OSA uniform color set as test stimuli in the two color-appearance modes. It is shown in our results that both aperture and surface color spaces were consistently divided into the 11 basic color categories, and that positions and borders of color categories depend on luminance (lightness) of test stimuli in the surface color mode, but almost independent of luminance in the aperture color mode. Furthermore, test stimuli made by a color CRT do not appear so different from those by color chips in both color-appearance modes. There are some similarities between our results and the Kelly’s chart.

Considerations on the calibration of color displays assuming constant channel chromaticity

AbstractTo calibrate a CRT color monitor, several assumptions are often made about its performance, one of the most accepted being constanel channel chromaticity. However, when the measurements are taken in a extended field of CRT screen, where it is assumed that only one primary phosphor is excited, the relative spectral radiance of the other primary phosphors that are contained in that field also contributes, if the background luminance is not zero. This contribution is greater at low levels of RGB channel stimulation and would invalidate the results obtained with calibration methods based on the hypothesis of constancy of chromaticity coordinates of RGB channels. We have studied this effect on the calibration of the CRT color monitor and, as a result, we propose a calibration that takes this effect into account. to evaluate the accuracy of the method, we have calculated color differences between the chromaticity that we wanted to reproduce and the one displayed with the CIELUV color‐difference formula, and the color tolerances with the line element of MacAdam ellipses.

Determination of constant Hue Loci for a CRT gamut and their predictions using color appearance spaces

AbstractA colorimetrically characterized computer‐controlled CRT display was used to determine 24 loci of constant perceived hue for pseudo‐object related stimuli, sampling the display's interior color gamut at constant lightness and the edge of its gamut at variable lightness. Nine observers performed three replications generating matching data at 132 positions. the constant hue loci were used to evaluate the correlation between perceived hue and hue angle of CIELAB, CIELUV, Hunt, and Nayatani color appearance spaces. the CIELAB, CIELUV, and Hunt spaces exhibited large errors in the region of the blue CRT primary, while the Nayatani and CIELUV spaces produced large errors in the region of the red primary for constant lightness stimuli. Along the edge of the CRT's color gamut (variable lightness stimuli), all the spaces had a similar trend, large errors in the cyan region. the differences in performance between the four spaces were not statistically significant for the constant lightness stimuli. For the variable lightness stimuli, CIELAB and CIELUV had statistically superior performance in comparison with the Nayatani space and equal performance in comparison with the Hunt space. It was concluded that for imaging applications, a new color appearance space needs to be developed that will produce small hue error artifacts when used for gamut mapping along loci of constant hue angle. © 1995 John Wiley & Sons, Inc.

Beam spot shift in a dynamic astigmatism correction type (DQ-DAF) electron gun

This paper presents the results of an investigation to avoid the convergence error in color CRT guns operating with a dynamic focus correction. The dynamic spot shift as well as the spot coma can be avoided at the same time with a proper arrangement of the quadrupole and main lenses with an oblique incidence of the side beam. The design confirmation is also presented.

Measurement of Color CRT Beam Profile and Its Application to Focus Evaluation

A method for measuring electron beam profiles is developed with the goal of evaluating the focus of color CRT displays. To increase measurement speed, a two-dimensional sensor is used and the electron beam profile is measured from the light emission intensity of phosphor dots. The portion blocked by the shadow-mask is measured by applying a magnetic field from the glass panel side. The electron beam profile obtained by this method and the results of visual focus evaluation by character pattern are compared. Good agreement with the visual evaluation results is obtained using two types of beam cross-section areas in the high and low intensity regions.

カラーCRTのビーム形状高速計測とフォーカス評価への応用

カラーCRTのビーム形状高速計測とフォーカス評価への応用

A Simulation of the Influence of the Magnetization of the Shadow Mask on the Electron Beam Trajectory

It is well known that in color CRTs, color changes occur as the result of magnetization of the shadow mask and frame by an ambient magnetic field. In order to clarify the influence of the mask and frame quantitatively, we used an integral equation method to analyze the magnetization resulting when a shadow mask and frame are subjected to an ambient field. The electron beam trajectories were calculated using the derived magnetic field distributions, and the mislanding was computed to obtain a quantitative evaluation of the color change. The results of the numerical analysis agree well with experiment, and help to clarify the relation of the shielding to the amount of mislanding.

CRT colorimetry. part I: Theory and practice

AbstractThe relationship was derived for computer‐controlled color CRT displays between spectral radiant exitance emitted and digital counts. The derivation was historical and could be traced to pioneering work in photographic sensitometry, vacuum tube physics, and broadcast television. By performing radiometric measurements relative to a display's maximum exitance, the model simplified to a two‐stage model. The first stage was a nonlinear transformation relating normalized digital‐to‐analog converter values to device‐dependent monitor tristimulus values using model parameters of gain, offset, and γ. The second stage was a linear transformation where the device‐dependent monitor tristimulus values were transformed to device‐independent CIE tristimulus values. By using the model, colorimetric characterization accuracy of better than 0.5 CIELAB color‐difference units for 125 colors sampling the display color gamut was achieved by measuring the CIE tristimulus values of only eight colors. The model had equivalent performance to methods using extensive measurements and table lookup. © 1993 John Wiley & Sons, Inc.

Double‐Quadrupole DAF Gun for Self‐Converging Color CRTs

Abstract— A new dynamic astigmatism and focus (DAF) gun has been developed for high‐resolution color CRTs, resulting in a rounder spot than that produced by existing DAF guns. A quadrupole lens adjacent to the triode of a conventional DAF was added. This lens is driven by the same dynamic waveform as employed in conventional DAFs. The new gun solves the problem of elliptically distorted spot shapes characteristic of conventional DAF guns with a self‐converging deflection yoke.

The use of Lorentzian functions in the analysis of non‐Gaussian CRT spots

Abstract— The spot profile of the CRT electron beam is Gaussian at low currents, but exhibits tails at higher currents, such as those used by modern high‐resolution color CRTs. Lorentzian functions are proposed as an analytic model to represent these distributions. Experimental evidence is given and the effect on the resultant picture quality analyzed. The flexibility of the Lorentzian functions make them useful in simulation and modeling tasks.

Quantifying color constancy: Evidence for nonlinear processing of cone-specific contrast

Color constancy was studied by the method of comparing color samples under two different illuminants using a CRT color monitor. In addition to the classical approach in which one of the illuminants is a (standard) white, we performed experiments in which the range of differential illumination was extended by using pairs of lights that were both colored. The stimulus pattern consisted of an array of thirty-five color samples (including five neutral samples) on a white background. A trichromatic illuminant-object interaction was simulated analogous to that resulting from illumination by three monochromatic lights. The test samples, as seen under “test” and “match” illumination, were successively presented to the left and right eye (haploscopic matching). The data show systematic deviations from predictions on the basis of cone-specific normalization procedures like those incorporated in the Retinex algorithm and the von Kries transformation. The results can be described by a nonlinear response transformation that depends on two factors, receptor-specific sample/background contrast and the extent to which the illuminant stimulates the receptor system in question. The latter factor explains the deviations. These are mainly caused by the short-wave-sensitive system, as a consequence of the fact that this system can be more selectively stimulated than the other, spectrally less separated, cone systems.

マスクの磁化による電子ビーム軌道への影響シミュレーション

It is well known that, in a color CRT, color change occurs as a result of the magnetization of the shadow mask and frame in the enviromental magnetic field. In order to clarify the influence of the mask and frame quantitatively, We analyzed the magnetization by integral equation method when a shadow mask and frame were subjected to an ambient field. We calculated the electron beam trajectories by using the derived magnetic field distributions, and computed the miss-landing to evaluate the color change quantitatively. The results of the numerical analysis agree well with experiment, and aid in relating the shielding to the miss-landing.

開ロ色と表面色モードにおける色空間のカテゴリカル色名領域

When we indicate or describe an object in everyday lives we often use a color of the object. Although there are a million of colors around us we do not use so many colors, but categorize different colors into several color names. Eleven color names; red, green, yellow, blue, brown, orange, purple, pink, white, black and gray, have been qualified as basic color categories, that are used consistently among observers and occasions. In this study we measured categorical regions in a color space determined with a categorical color naming method using these 11 basic color names. Two color-appearance modes; aperture color mode and surface color mode, were tested. We employed both a color CRT monitor and a OSA uniform color set as test stimuli in the two color-appearance modes. It is shown in our results that both aperture and surface color spaces were consistently divided into the 11 basic color categories, and that positions and borders of color categories depend on luminance (lightness) of test stimuli in the surface color mode, but almost independent of luminance in the aperture color mode. Furthermore, test stimuli made by a color CRT do not appear so different from those by color chips in both color-appearance modes. There are some similarities between our results and the Kelly’s chart.

カラーディスプレイ管用非接続型漏洩磁界補償コイル

This paper introduces a new system which compensates for low frequency magnetic field leakage from color CRTs without significant deterioration in the CRTs quality.The system consists of two isolated closed-wire loops and a cylindrical ferrite core installed at the horizontal lead wire. One portion of each loop is wound around the ferrite core and another portion is mounted on the deflection yoke.Current is brought about in each loop by electromagnetic induction of the flux from the lead wire. This generates the compensation field.By using this system, the compensating power can be suppressed to 3% of the horizontal deflection power. Moreover, the picture screen quality deterioration disappears because of the compensation field distribution arrangment in the deflection region.

レーザースペックル法を用いた眼底血流実時間測定

Real-time measurement of blood flow in retina is achieved by developing a hardware-logic board for the Laser Flowgraphy system. The retina is illuminated by a diode laser through a fundus camera and the spot is imaged onto the area sensor. The speckle field is scanned for certain numbers of time, and the blur rate of the speckles is calculated by the logic board. The maps of blood flow are obtained in every 120 msec and are displayed successively in the color CRT screen of a personal computer. The time varying blood flow in arterioles, as well as in veinules is clearly observed; which is synchronized to the heart pulse

Experimental evaluation of an operator decision aid system for BWR power plants

An experiment was carried out to evaluate the effectiveness of an integrated operator decision aid (IODA) system for boiling water reactor (BWR) power plants. The IODA was developed to enhance the operating safety, reliability and quality of plants. It assists an operator's monitoring and diagnostic capabilities under adverse plant situations using computers and color CRT display devices. Three functions—a standby systems management system (SSMS), a disturbance analysis system (DAS), and a post-trip operational guidance (PTOG) system—have been developed as aids corresponding to the operator's various roles in the safe operation of a nuclear power plant. These functions were designed with full consideration of the operator's problem-solving process, and they have been integrated into a comprehensive IODA system for abnormal BWR power plant conditions. To ensure the applicability of the test results to real-life situations, emphasis was placed on establishing realistic test conditions—including a fully equipped experimental control room, a full-scope plant simulator, participation of experienced operating crews, and well-designed test transient scenarios. Experimental data were collected by means of computers and audio-visual devices, and were processed and summarized to facilitate analysis. Qualitative analysis of the test results was performed with emphasis on the decision-making process of an operator. The analysis points to the utility of the IODA as an operator aid, especially in diagnosing adverse plant situations and in formulating strategies for countermeasures.

Chromatic adaptation to natural and incandescent illuminants

A color CRT image display system was used to present adapting backgrounds that were spatially and temporally varied. Three observers adjusted the chromaticity of test stimuli to produce an achromatic appearance under a variety of adapting conditions. The achromatic-appearing chromaticities were used as measures of the observers' states of chromatic adaptation. The spatial configuration of the adapting background was varied to measure the spatial extent of the mechanisms responsible for chromatic adaptation. The temporal configuration of the adapting background was varied to measure the time-course of these mechanisms. The results show that chromatic adaptation is spatially localized with a time-course on the order of 10 sec. Since the mechanisms were shown to be spatially localized, the observed temporal integration across eye movements is required to allow these mechanisms to adjust to the spatially integrated scene chromaticity.

Magnetic Field Distribution of Shadow Mask having a Magnetic Circuit around a Frame Periphery and its Affection to the Electron Beam Trajectory

The shadow mask in a color CRT is a soft thin iron plate which regulates the electron beam path. The mask may be magnetized by ambient magnetic fields, and the magnetization may change the beam path. As a result of the mask magnetization, the CRT screen may show color changes. We introduced magnetic circuits on the periphery of a shadow mask frame in order to decrease the mask and frame magnetization. The magnetic field distribution around the shadow mask was measured, and the effect of the circuits was evaluated through calculations of the change in electron trajectory. The addition of a magnetic circuit may be effective for decreasing the color change in CRT screens.

X線ディスクスキャナによる高温高圧下に於ける管内蒸気水二相流の可視化

To improve the accuracy of BWR safety evaluation, it is necessary to measure void distributions in high-pressure steam-water two-phase flow. For this purpose, the authors have developed a new technique using a high-speed rotating disc for X-ray beam scanning. Using the disc scanner, void distributions were measured across a pipe cross-section every 2.5 ms under various conditions. The device can visualize the transient flow pattern on a color CRT in real time. Using the measured flow pattern, a new flow-pattern map was made for high-pressure steam-water two-phase flow in a horizontal pipe. Results were compared with a flow pattern map used in the TRAC code. The measured flow patterns are about the same as those of the TRAC code. There seems to be little pressure effect on the flow pattern borders as pressure changes from.5 MPa to 7 MPa.

3-D TV without glasses

A hologram-like, 3-D, high-resolution, stereoscopic video display technique based on a color CRT is described. The technique is unique in that it is autostereoscopic, i.e., no special glasses, goggles, panels, helmets, or two-channel optical systems are required by the viewer to see depth. Any image that can be put into a television-like format can be displayed. This allows real-time scanning sensor data to be viewed with depth in a format familiar to the viewer. An implementation using real-time sensors is shown.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>