• Ocean Science Journal
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• v.41 no.2
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• pp.97-104
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• 2006

A useful radiance-converting method was developed to convert the Landsat-7 ETM+thermal-infrared (TIR) band's radiance ($L_{{\lambda},L7/ETM+}$) to that of Landsat-5 TM TIR ($L_{{\lambda},L5/TM+})$ as: $L_{{\lambda},L5/TM}=0.9699{\times}L_{{\lambda},L7/ETM+}+0.1074\;(R^2=1)$. In addition, based on the radiance-converting equation and the linear relation between digital number (DN) and at-satellite radiance, a DN-converting equation can be established to convert DN value of the TIR band between Landsat-5 and Landsat-7. Via this method, it is easy to integrate Landsat-5 and Landsat-7 TIR data to retrieve the sea surface temperature (SST) in coastal waters on the basis of local empirical algorithms in which the radiance or DN of Lansat-5 and 7 TIR band is usually the only input independent variable. The method was employed in a local empirical algorithm in Daya Bay, China, to detect the thermal pollution of cooling water discharge from the Daya Bay nuclear power station (DNPS). This work demonstrates that radiance conversion is an effective approach to integration of Landsat-5 and Landsat-7 data in the process of a SST retrieval which is based on local empirical algorithms.

• Korean Journal of Optics and Photonics
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• v.17 no.5
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• pp.391-395
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• 2006

In this paper, radiometric calibration of a FTIR spectrometer for passive remote sensing application was introduced and verified. Radiometric calibration is a significant signal processing procedure to retrieve the object radiance from the measured spectrum. The object radiance is measured and registered distorted by the detector's responsivity dependent on wavelength and instrument self-emission. Radiance of two temperature points, hot temperature and cold temperature, from a well-controlled blackbody was measured and used to obtain the scale factor and offset factor which are required for radiometric calibration. For gas phase C2H5OH. radiometric calibration was done and verified through comparison of its emission line width and intensity with the standard spectrum.

• Korean Journal of Remote Sensing
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• v.36 no.6_2
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• pp.1629-1634
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• 2020

It is essential to convert the Digital Number (DN) measured from Earth observing satellites into the physical parameter of radiance when deriving the geophysical parameter such as surface temperature in the satellite data processing. The purpose of this study is to update the DN·Radiance equation established from lab measurements, using the KOMPSAT-3A mid-wave infrared data and the MODTRAN radiative transfer model. Results of this study show that the improved DN·Radiance equation allows us to produce the realistic values of radiance. We expect in the forthcoming study that the radiances calculated as such should be more quantitatively validated with the use of relevant in-situ measurements and a radiative transfer model.

• Journal of Korea Multimedia Society
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• v.17 no.11
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• pp.1270-1278
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• 2014

The modern infrared (IR) imaging systems use mainly one or more wavelength bands among short wavelength IR (SWIR), middle wavelength IR (MWIR), and long wavelength IR (LWIR) bands. In the process of IR image synthesis and modeling, IR image wavelength-band conversion which transforms arbitrary band image to other band one is required. The wavelength-band conversion procedure includes a temperature estimation process of an object surface. However, in this procedure, an approximated Planck's radiation equation causes errors in estimated temperature. In this paper, we propose an estimation temperature error attenuation method in IR image band conversion procedure. The estimated temperature is corrected with a slope information of radiance according to it. The corrected temperature is used for generation of the other band IR image. The verification of proposed method is demonstrated through the simulation.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1201-1206
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• 2004

Sonoluminescence (SL) characteristics such as pulse shape, radiance and spectrum radiance from submicron bubbles were investigated. In this study, a set of analytical solutions of the Navier-Stokes equations for the gas inside bubble and equations obtained from mass, momentum and energy equations for the liquid layer adjacent the bubble wall were used to estimate the gas temperature and pressure at the collapse point, which are crucial parameters to determine the SL characteristics. Heat transfer inside the gas bubble as well as at the liquid boundary layer, which was not considered in the most of previous studies on the sonoluminescence was taken it into account in the calculation of the temperature distribution inside the bubble. It was found that bremsstrahlung is a very possible mechanism of the light emission from either micron or submicron bubbles. It was also found that the peak temperature exceeding $10^{6}$ K in the submicron bubble driven at 1 MHz and 4 atm may be due to the rapid change of the bubble wall acceleration near the collapse point rather than shock formation.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.4
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• pp.97-103
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• 2006

A synthetic infrared image can be effectively utilized in various fields such as the recognition and tracking of targets as long as its quality is good enough to reflect the real situations. One way to improve its quality is to use the reference atmosphere which best describes atmospheric properties of regional areas. The east asian reference atmosphere has been developed to represent atmospheric properties of the east asia including Korean peninsula. However, few research has been conducted to examine the effects of this east asian reference atmosphere on the modeling and simulation. In this regard, this paper analyzes the effects of the east asian reference atmosphere on a synthetic infrared image. The research compares the atmospheric transmittance, the surface temperature, and the radiance obtained by using the east asian reference atmosphere with those of the midlatitude reference atmosphere which has been widely applied in the east asia. The results show that the differences of the atmospheric transmittance, the surface temperature, and the radiance between the east asian reference atmosphere and the midlatitude reference atmosphere are significant especially during the daytime. Therefore, it is recommended to apply the east asian reference atmosphere for generating a synthetic infrared image with targets in the east asia.

• Korean Journal of Remote Sensing
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• v.38 no.4
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• pp.343-353
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• 2022

An attempt to derive the surface temperature from the Korea Multi-purpose Satellite (KOMPSAT)-3A mid-wave infrared (MWIR) data acquired over the southern California on Nov. 14, 2015 has been made using the MODerate resolution atmospheric TRANsmission (MODTRAN) radiative transfer model. Since after the successful launch on March 25, 2015, the KOMPSAT-3A spacecraft and its two payload instruments - the high-resolution multispectral optical sensor and the scanner infrared imaging system (SIIS) - continue to operate properly. SIIS uses the MWIR spectral band of 3.3-5.2 ㎛ for data acquisition. As input data for the realistic simulation of the KOMPSAT-3A SIIS imaging conditions in the MODTRAN model, we used the National Centers for Environmental Prediction (NCEP) atmospheric profiles, the KOMPSAT-3Asensor response function, the solar and line-of-sight geometry, and the University of Wisconsin emissivity database. The land cover type of the study area includes water,sand, and agricultural (vegetated) land located in the southern California. Results of surface temperature showed the reasonable geographical pattern over water, sand, and agricultural land. It is however worthwhile to note that the surface temperature pattern does not resemble the top-of-atmosphere (TOA) radiance counterpart. This is because MWIR TOA radiances consist of both shortwave (0.2-5 ㎛) and longwave (5-50 ㎛) components and the surface temperature depends solely upon the surface emitted radiance of longwave components. We found in our case that the shortwave surface reflection primarily causes the difference of geographical pattern between surface temperature and TOA radiance. Validation of the surface temperature for this study is practically difficult to perform due to the lack of ground truth data. We therefore made simple comparisons with two datasets over Salton Sea: National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory (JPL) field data and Salton Sea data. The current estimate differs with these datasets by 2.2 K and 1.4 K, respectively, though it seems not possible to quantify factors causing such differences.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.3
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• pp.342-349
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• 2010

This paper is a foundation work in developing a software for generating infrared images from a scene with various objects. The spectral radiance received by a remote sensor is consisted of the self-emitted, reflected and scattered components. In general, the self-emitted component is the most important part for generating Infrared signatures from the object. In this paper, the infrared image generation considering various surface temperature and optical surface property of a flat plate is demonstrated in MWIR($3{\sim}5{\mu}m$) and LWIR($8{\sim}12{\mu}m$) regions for different spatial resolutions of the images. Resulting spectral radiance values in the MWIR($3{\sim}5{\mu}m$) and LWIR($8{\sim}12{\mu}m$) regions arrived at the infrared sensor are compared numerically and graphically by recognizing that they are strongly dependent on the surface conditions such as the surface temperature and the surface emissivity. And these infrared images are also shown to be strongly dependent on the resolutions of the infrared imaging devices as well. This study reveals that the surface conditions are more dependent on the radiance level from the surface while the resolution of the imaging device is more responsible for identifying the shape of object.

• Korean Journal of Optics and Photonics
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• v.26 no.1
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• pp.30-37
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• 2015

The design and implementation of a radiative temperature measurement system for a flash light are carried out. Since a massive amount of energy is emitted within a very short time, it is impossible to measure the temperature of a flash with a conventional method. It is also irrelevant to measure one with an optical noncontact method. In this paper, a radiative temperature measurement system using the ratio of spectral radiances over mid- and long-wavelength infrared (IR) is designed and implemented. The implemented system utilizes optical bandpass filters to divide the wavelengths within the mid- and long-wavelength IR ranges, and pyroelectric IR detectors to measure the incident optical power of each wavelength-divided channel. It is shown that the measured radiative temperature of a flash is in the range of 1393 to 1455 K. This temperature-measurement system can be utilized to obtain information about the spectral radiance of a flash as a light source, which is of crucial importance to approaching the modeling and simulation of the various effects of a flash.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.5
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• pp.84-91
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• 2008

The spectral radiance received by a remote sensor at a given temperature and wavelength region is consisted of the self-emitted component directly from the object surface, the reflected component of the solar irradiation at the object surface, and the scattered component by the atmosphere without ever reaching the object surface. The IR image of a ship is mainly affected by location, meteorological condition(atmosphere temperature, wind direction and velocity, humidity etc.), atmospheric transmittance, solar position and ship surface temperature etc. Computer simulations for prediction of the IR signatures of ships are very useful to examine the effects of various meteorological conditions. In this paper, we have acquired the IR signature for different meteorological conditions by using two different computer programs. The numerical results show that the IR image contrast as compared to the background sea considering the atmosphere temperature and wind velocity.