• Title/Summary/Keyword: contrast radiance intensity

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Thermal Signature Characteristics of Clothed Human Considering Thermoregulation Effects (체온 조절 작용을 고려한 의복 착용 시의 인체 열상신호 특성 분석)

  • Chang, Injoong;Bae, Ji-Yeul;Lee, Namkyu;Kwak, Hwykuen;Cho, Hyung Hee
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.32 no.2
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    • pp.109-116
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    • 2019
  • Survivability of soldiers has been greatly threatened by the development of thermal observation device(TOD). Therefore, infrared, especially thermal, stealth technology is applied to combat suit to avoid detection from TOD. In this study, prior to the thermal camouflage performance evaluation of combat suit, thermal signature characteristic from clothed the human body was analyzed considering the realistic condition for human surface temperature compared to that from unclothed human body. To get the realistic surface temperature distribution of human, thermoregulation and multi-layer skin structure model is applied to the human model. Based on temperature distribution, surface diffuse radiance in thermal range is calculated and by assuming the background conditions, contrast radiance intensity(CRI) characteristic of human body is analyzed. By wearing clothing, the CRI between background and human body became reduced in low emissive background but in high emissive background, the contrast is much more prominent. Therefore, this issue should be considered in design process of thermal camouflage combat suit.

Analysis on Infrared Stealth Performance with Emissivity Controlled Aircraft Surface Structure at Various Background (항공기 적외선 스텔스 기술 적용을 위한 다양한 배경조건에서의 방사율 제어구조 성능 분석)

  • Bae, Munjang;Kim, Taehwan;Kim, Taeil;Jung, Daeyoon;Cho, Hyung Hee
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.29 no.5
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    • pp.455-461
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    • 2016
  • Survivability of an aircraft has been greatly threatened by the development of a weapon system using infrared. Therefore, the infrared stealth technology is a very important technique to improve the survivability of an aircraft. In this study, the infrared signal of an aircraft was analyzed which corresponding to the aircraft surface temperature and environmental conditions with various surface conditions(especially emissivity changed). Based on the analyzed infrared signal, the optimized surface emissivity was suggested to reduce the average contrast radiance and contrast radiant intensity(CRI). In addition, we confirmed that the infrared contrast radiant intensity between the aircraft and the background can be minimized through an appropriately controlled surface emissivity of the aircraft at specific background.

Study on Effectiveness of Ocean Meteorological Variables through Sensitivity Analysis of Ship Infrared Signature (함정 적외선신호 민감도 해석을 통한 기상변수 영향에 관한 연구)

  • Cho, Yong-Jin;Jung, Ho-Seok
    • Journal of Ocean Engineering and Technology
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    • v.27 no.3
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    • pp.36-42
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    • 2013
  • According to a study on improving ship survivability, an IR signature represents the contrast radiance intensity between the radiation signature from a ship and the background signature. It was found from applying stealth techniques to the process of ship development that the IR signature is remarkably sensitive and dependent on the environment. In this study, marine climate data for the sea near the Korean Peninsula were collected, and the marine meteorological environment in Korean waters was defined. Based on this data, a study on the sensitivity of the IR signature of target objects was performed using analytical methods. The results of the research indicated that clouds have important effects on the infrared signature, but the velocity of the wind and the humidity have only slight effects on the IR signature. In addition, the air and seawater temperatures had hardly any effect on the IR signature, but it is judged that additional study is needed.

Variation of Human Thermal Radiation Characteristics Applying Different Clothing Materials (의복 소재 변경에 따른 인체 열상신호 변화 특성)

  • Chang, Injoong;Bae, Ji-Yeul;Lee, Namkyu;Kwak, Hwykuen;Cho, Hyung Hee
    • Journal of the Korea Institute of Military Science and Technology
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    • v.22 no.5
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    • pp.644-653
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    • 2019
  • With the development of themal observatory device(TOD), thermal camouflage system has been applied not only to the weapon system but also to the combat suit for soldiers. In this paper, the characteristic of thermal radiation of human body depending on the clothing material properties was analyzed through numerical simulations. The bioheat equation with thermoregulatory model was solved to obtain the realistic surface temperature of human body and these results are combined with the emissivity of human skin and clothing in order to calculate the thermal signature from the human body. According to each thermal resistance of clothing, the optimal background radiance which makes contrast radiance intensity(CRI) be lowest is different. Also, the average CRI variation per thermal resistance change is about twice as much as the case of evaporative resistance change.

A Comparative Study between Measurement and Prediction Results of a Naval Ship Infrared Signature in the Marine Environment (해상환경에서 함정 적외선 신호 측정 및 예측결과 비교 분석 연구)

  • Kim, Jung-Ho;Yoon, Yoon-Sik
    • Journal of the Society of Naval Architects of Korea
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    • v.48 no.4
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    • pp.336-341
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    • 2011
  • Ship infrared signature is the cause of detection and tracking by infrared sensor and anti-ship missile seeker. Recent warships have been applied the infrared stealth technology to reduce own ship infrared signature and tested to validate own ship infrared signature level. This study describes the two issues. Firstly, we describe the infrared measurement concept and infrared signature level establishment method that have been performed. Secondly, we compare and analyze the error components between the infrared measurement and simulation result.