• IEMEK Journal of Embedded Systems and Applications
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• v.8 no.2
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• pp.111-119
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• 2013

This paper proposes one method on photometric stereo calibration using the constraint on light source directions in which the light sources have the unknown tilt and slant angles but the slant angles are the same. First, the constraint is analyzed based on the equation of linear ambiguity which leads to the conclusion that another constraint should be added to solve the calibration completely. Later, the combination of constraint on light source directions and the constraint that there exists at least six surface patches having known albedos is exploited to resolve the linear ambiguity up to an accurate and close-form solution. The effective performance of the proposed method is demonstrated through experiment results.

• Journal of The Korean Astronomical Society
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• v.20 no.2
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• pp.63-94
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• 1987

Using many homogeneous data of DDO and UBV colors for all luminosity classes and physical quantities known from spectroscopic observations, new calibration schemes with DDO photometric parameters are presented for metal abundance, effective temperature and surface gravity of stars. And an intrinsic color relation is derived for the reddening estimate.

• Journal of Sensor Science and Technology
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• v.21 no.2
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• pp.96-102
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• 2012

This paper addresses photometric distortion problems of a compact 3D scanning sensor which is composed of a micro-size and inexpensive camera-projector system. Recently, many micro-size cameras and projectors are available. However, erroneous 3D scanning results may arise due to the poor and nonlinear photometric properties of the sensors. This paper solves two inherent photometric distortions of the sensors. First, the response functions of both the camera and projector are derived from the least squares solutions of passive and active calibration, respectively. Second, vignetting correction of the vision camera is done by using a conventional method, however the projector vignetting is corrected by using the planar homography between the image planes of the projector and camera, respectively. Experimental results show that the proposed technique enhances the linear properties of the phase patterns that are generated by the sensor.

• Journal of The Korean Astronomical Society
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• v.10 no.1
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• pp.31-38
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• 1977

To reduce the instrumental and calibration errors in the photoelectric photometry as much as possible it is necessary to select the optimum photocell voltage and energy attenaution and to observe as many standard stars as possible over the wide range of color, spectral type and air mass.

• The Bulletin of The Korean Astronomical Society
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• v.5
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• pp.21.2-21.2
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• 1980

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.66.4-67
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• 2020

Gyeonggi science high school for the gifted (GSHS) installed 60cm telescope, which is waiting for student observers. It is essential to understand the characteristics of the photometric system, consisting of telescope, filter, and CCD, to get reliable data. CCD images of SA98 Landolt standard field and M67 were obtained on 19th March 2020. The images of each field were combined by filters, i.e., we ignored the monochromatic atmospheric extinction since the photometric objects themselves are standard stars. 24 standard stars in SA98 field and 12 standard stars in M67 were used to derive the tentative transformation equation between our bv photometric system and Johnson BV photometric system. In this poster, we present the preliminary standardization result for Johnson BV photometric system in GSHS 60cm telescope. The reproductivity is discussed by comparing color coefficients of two fields. We plan to extend this process to Johnsons-Cousins BVRI photometric system and narrow-band filters for flux calibration.

• Archives of Pharmacal Research
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• v.6 no.2
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• pp.103-108
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• 1983

Such sulfur-containing drugs as chlorpromazine, sulfonamides and thiazides were determined by gas chromatography with flame photometric detector (FPD) and flame ionization detector (FID). 0.6% QF-1 or 3% SE-30 on Chromosorb WAWDMCS were found suitable for drugs listed above. In the experimental conditions given maximum response the FPD response and the response ratio of FPD increased with the number of sulfur atom per molecule. It was possible to obtain a linear calibration curve from $10^{-9}$ / mole to $2{\times}10^{-8}$ / mole and to analyze variety of sulfur drugs by the calibration curve of one sulfur standard.

• YAKHAK HOEJI
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• v.29 no.5
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• pp.227-233
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• 1985

A new method of determination of fatty acid using gas chromatography-flame photometric detector (GC-FPD) is described. Fatty acid was methylthiomethyl-esterified with methylthiomethy chloride in 1,8-diazabicyclo [5,4,0]-undec-7-ene catalyst and its concentration measured by GC-FPD with 3%OV-1 or 3% FS-1 column. The FPD responses of thirteen fatty acid methylthiomethyl esters were examined and were proportional to the concentration of the esters without regard to their chemical structures. Consequently it was possible to determine various fatty acid using one standard calibration curve by GC-FPD. We could rapidly and conveniently determine varous fatty acids using one standard calibration curve by GC-FPD. We could rapidly and conveniently determine 13 fatty acids in Ginseng Radix alba by this method.

• The Bulletin of The Korean Astronomical Society
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• v.4
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• pp.26.3-27
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• 1979

• Journal of the Korean earth science society
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• v.43 no.1
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• pp.1-22
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• 2022

We provide a detailed description of the installation and operation of a remote spectroscopic meteor observation system at Unjangsan optical astronomy observatory. Three light-sensitive charge-coupled device cameras were installed, and two cameras had a diffraction grating attached to the front of the lens. Station employ sensitive "Watec-902H2" cameras in combination with f/1.2 lenses were installed in November 2019. Diffraction gratings for spectral observations were used at 500 l/mm. Observations were conducted from November 2019 to June 2020. We employed the SonotaCo UFO software suite for meteor detection. Subsequently, meteor spectra were analyzed using field-tested RSpec software. To analyze the observation images, astronomical calibration and photometric calibration were performed, and the chemical elements of the meteor were determined. The study results are presented along with the system setup installation and operation experience. Brief information regarding the origin of the meteor was also provided based on the results.