• Korean Journal of Digital Imaging in Medicine
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• v.10 no.1
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• pp.21-28
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• 2008

Diagnostic display monitor QA according to AAPM TG18 is usually performed by PACS administrator, product manager and reading doctor, and for acceptance testing and periodic quality control evaluation, a combination of visual and quantitative tests can be used, as outlined in sections 5 and 6 of 'assessment of display performance for medical imaging systems'. Although many display tests can be performed visually, a more objective and quantitative evaluation of display performance requires special test tools. The required instruments vary in their complexity and cost, depending on the context of the evaluation(research, acceptance testing, or quality control) and how thorough the evaluation needs to be. Objective and reliable assessment of many display characteristics can be performed with relatively inexpensive equipment, So, we made 'AAPM TG18 guiding instrument' to ues variable purpose of the evaluation of 'geometrical distortions(quantitative"', 'veiling glare(visual)' and 'sensor calibration'. The spatial measurements for the quantitative evaluation of geometric distortions, and the measurement of the veling-glare ring response function which provides information regarding the spatial extent of the luminance spread, can be performed using the TG18 guiding instrument can be used to sensor calibration to standardize the basic rate of 0% luminance when periodic calibration.

• Advanced Industrial SCIence
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• v.2 no.4
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• pp.28-35
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• 2023

In this paper, a diffractive optical element was designed to create lighting patterns that satisfy the requirements of adaptive headlight systems for normal road mode, highway mode, and wet road mode, and this was rendered into a GDSII stream format file.To verify the effectiveness of the light distribution formed by the diffractive optical elements and the realization of white light, simulations based on Field Tracing and Ray Tracing were conducted, confirming the satisfaction of position and luminance requirements at the transformation beam measurement points. Based on this research, it is anticipated that the implementation of adaptive headlights would be possible, enabling the reproduction of luminance contrast and the creation of a simple-structured adaptive headlight system.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1783-1785
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• 1999

In this paper, we apply V-Q Lissajoucs' figure for observation of a V-Q (Voltage-Charge) hysteresis loop at interface between phosphor and insulation layer in P-ELDz which are a simple structure and the back lighting of LCDs (Liquid Crystal Display). In V-Q Lissajous' figure, we measured a change of hysteresis loop according to the thickness of Insulation and phosphor layer. From experiment result, we will be obtained a optimum thickness of insulation with comparing the correlation of a V-L (Voltage-Luminance) and V-Q hysteresis loop.

• KIEAE Journal
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• v.7 no.2
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• pp.31-37
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• 2007

Despite of many supportive research to the usefulness of slide evaluation on environment of outdoor lighting, study method of using slides have provoked many discussions of its manifestation of reality of field conditions. This study aims to compare the results of slide survey with that of field survey. Distant view and short range view of nightscape of Seoul were selected. Field measurement of luminance and chromaticity were conducted and questionnaire survey were conducted. Frequency analysis, T-test, factor analysis were conducted. Results shows that distant view and short range view of field survey have better visual atmosphere than slide survey. In addition, slide survey on distant view shows lowest values. Difference between field survey and slide survey on distant view is much bigger than the results of short range view.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.34-35
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• 2002

Large-screen projectors for video applications and computer monitors are convenient instruments for conference presentations as well as for TV use at home. Recently, CRT and LCD projectors have achieved higher resolutions and luminance in the projection TV The large surface of the CRT compared to the LCD allows a great number of pixels to be displayed, while simultaneously providing maximum brightness of the final picture. (omitted)

• Journal of Information Display
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• v.5 no.3
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• pp.35-40
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• 2004

In this study, we collected data used to formulate the relationship between quantitative metrological parameters in CRT display and the perceived focus quality. Human perception of the focusing quality was evaluated in terms of user feedback scores regarding the character legibility from four highly trained inspectors. Thirteen CRT monitors from five different manufacturers were compared relatively with respect to the norm monitor. The profile of electron beam such as spot size and the shape of distribution made by electron beam, contrast, convergence of RGB beams, and luminance characteristics were measured using a precision measurement system. Linear regression analysis and artificial neural network models were used to formulate the relationship between human perception and the quantitative measurements. The accuracy of the formulated linear regression model ($R^2$=0.515) was not satisfactory but the nonlinear neural network model ($R^2$=0.716) was fairly convincing and robust even the utilized data included subjective differences.

• 한국가시화정보학회:학술대회논문집
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• 2004.11a
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• pp.52-55
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• 2004

Thermo-chromic Liquid Crystal(TLC) particles were used as temperature sensor for thermal fluid flow. $1K\times1K$ CCD color camera and Xenon Lamp(500W) were used for the visualization of a Hele-Shaw cell. The characteristic between the reflected colors from the TLC and their corresponding temperature shows strong non-linearity. A neural network known as having strong mapping capability for non-linearity is adopted to quantify the temperature field using the image of the flow. Improvements of color-to-temperature mapping was attained by using the local color luminance (Y) and hue (H) information as the inputs for the constructed neural network.

• Journal of the Korean institute of surface engineering
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• v.30 no.1
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• pp.57-62
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• 1997

Green-emitting $ZnGa_2O_4$ : Mn phosphors were synthesized by a thermal method and their low-voltage cathodoluminescent characteristics were examined for the field emitter display (FED) application. Low efficiency of $ZnGa_2O_4$ : Mn phosphors could be ascribed to the low penetration depth of into phosphors, which might results in charge accumulation on the phosphors screen. For increasing cathodoluminescent of $ZnGa_2O_4$ : Mn under low voltage excitation, wide band-gap oxide materials were added to the $ZnGa_2O_4$: Mn powder. It is found that the luminance can be increased by 20%. Measurement of leakage current on the phosphor screen shows that the enhancement of low-voltage cathodoluminescent by additive materials is mainly due to the consumption of surface charges on the phosphor.

• Journal of Information Display
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• v.11 no.2
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• pp.57-62
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• 2010

A method of characterizing time-sequential stereoscopic 3D displays based on the measurement of the temporal behavior of the systems vs. the grey levels is proposed. An Nvidia 3D vision kit with a 3D-ready SAMSUNG 2233RZ LCD display is characterized in the paper. OPTISCOPE SA especially designed for the precise measurements of the luminance and temporal behavior of LCD displays was used. The transmittance and response time of the shutter glasses was first evaluated. Then the grey-to-grey response times of the display were measured. The 2D and 3D behaviors of the display were then compared. Finally, the temporal behavior of the complete system was modeled, and the grey-level variations on one view were deduced as a function of the synchronization and level of the other eye. The main sources of imperfection were identified and quantified, and a full computation of the system performances was done.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2218-2220
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• 1999

Plasma Display Panel(PDP) has mirco-cell, so it is difficult to know the physical properties of particles in PDP cell. To know this, we made a cell that is 200 times as large as a general PDP cell. Using this cell, the temperature and the density of electrons have been measured by the fast scanning probe.