Infrared and Laser Engineering, Volume. 50, Issue 8, 20200371(2021)

Target detection performance of infrared spectrum with diffractive optical system

Kai Zhou1,2, Daojing Li1、*, Yefei Wang3, Yuan Yao3, and Ming Qiao1
Author Affiliations
  • 1National Key Laboratory of Microwave Imaging Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China
  • 2University of Chinese Academy of Sciences, Beijing 100049, China
  • 3Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China
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    Figures & Tables(10)
    Optical path diagram of infrared camera system based on diffractive optical system
    Graph of relative radiant exitance function of black-body when takes different ranges. (a) takes entire range; (b) takes 2.4×103-3.6×103μm·K ; (c) takes 0-1.5×103μm·K取不同范围时黑体相对辐出度函数图。(a) 取全部范围;(b) 取2.4×103~3.6×103μm·K;(c) 取
    Same spectral curve of radiance at target/background temperature difference of 1 K
    Differrent spectral curve of radiance at target background temperature difference of 1 K
    Principle block diagram of the laser local oscillator unit detector
    • Table 1. Relevant parameters for calculating \begin{document}${D^*}$\end{document}

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      Table 1. Relevant parameters for calculating \begin{document}${D^*}$\end{document}

      ParametersValueParametersValue
      Conversion factor $K$0.7F number of optical systems 1
      Grass background temperature in Summer ${T_B}$303 KDetector peak wavelength ${\lambda _p}$$10.8\;{\text{μm}}$
      First radiation constant ${c_1}$$3.741\;5 \times {10^8}\;{\rm{W}} \cdot \;{{\text{μm}}^4} \cdot \;{{\rm{m}}^2}$Second radiation constant ${c_2}$$1.438\;8 \times {10^4}{\text{μm}} \cdot \;{\rm{K}}$
      Optical system transmittance during testing ${\eta _{0t}}$0.6Background emissivity0.93
      Noise equivalent temperature difference $NETD$$40 \times {10^{ - 3}}\;{\rm{K}}$Integration time during testing ${t_{{\rm{int}} 1}}$$34.56 \times {10^{ - 6}}\;{\rm{s}}$
      Detector pixel area ${A_d}$${\left( {14 \times {{10}^{ - 6}}} \right)^2} \times {10^4}\;{\rm{c}}{{\rm{m}}^2}$Detector specific detectivity ${D^*}$$5.{\rm{4}} \times {10^{10}}\;{\rm{cm}} \cdot \;{\rm{H}}{{\rm{z}}^{1/2}} \cdot \;{{\rm{W}}^{ - 1}}$
    • Table 2. System parameters

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      Table 2. System parameters

      ParametersValueParametersValue
      Signal extraction factor $\delta $0.707Number of pixels occupied by the vehicle target on the focal plane ${N_t}$1
      Atmospheric transmittance ${\tau _a}$0.75Optical system aperture ${D_0}$100 mm
      Optical system transmittance ${\eta _0}$0.6Optical system entrance pupil area ${A_0}$$79 \times {10^{ - 4}}\;{{\rm{m}}^2}$
      Integration time in actual work ${t_{{\rm{int}} 2}}$$10 \times {10^{ - 3}}\;{\rm{s}}$Target effective radiation area ${A_t}$$4 \times {10^4}\;{\rm{c}}{{\rm{m}}^2}$
      Background surface temperature303 KTarget surface temperature304/306/308 K
      Detection range R15 kmDetector specific detectivity ${D^*}$$1.4 \times {10^9}\;{\rm{cm} } \cdot \;{\rm{H} }{ {\rm{z} }^{1/2} } \cdot \;{ {\rm{W} }^{ - 1} }$
    • Table 3. Infrared detection SNR under different optical systems when the spectral characteristics of target/ background are same

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      Table 3. Infrared detection SNR under different optical systems when the spectral characteristics of target/ background are same

      ParametersValue
      Target/background emissivity0.93/0.93
      Target/background spectral range8-12 μm
      Target radiance$\left( {3.82/3.94/4.06} \right) \times {\rm{1}}{{\rm{0}}^{{\rm{ - 3}}}}\;{\rm{W}} \cdot {\rm{c}}{{\rm{m}}^{ - 2}} \cdot {\rm{s}}{{\rm{r}}^{ - 1}}$
      Background radiance$3.75 \times {\rm{1}}{{\rm{0}}^{{\rm{ - 3}}}}\;{\rm{W}} \cdot {\rm{c}}{{\rm{m}}^{ - 2}} \cdot {\rm{s}}{{\rm{r}}^{ - 1}}$
      SNR of infrared detection with traditional optical system3.9/11.9/20
      SNR of infrared detection with diffractive optical system0.19/0.55/0.92
    • Table 4. Infrared detection SNR under different optical systems when the spectral characteristics of target/background are different

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      Table 4. Infrared detection SNR under different optical systems when the spectral characteristics of target/background are different

      ParametersValue
      Target/background emissivity0.93/0.2
      Target/background spectral range10.4-11 μm/8-12 μm
      Target radiance$\left( {5.75/5.92/6.1} \right) \times {\rm{1}}{{\rm{0}}^{{\rm{ - 4}}}}\;{\rm{W}} \cdot {\rm{c}}{{\rm{m}}^{ - 2}} \cdot {\rm{s}}{{\rm{r}}^{ - 1}}$
      Background radiance$8.08 \times {\rm{1}}{{\rm{0}}^{{\rm{ - 4}}}}\;{\rm{W}} \cdot {\rm{c}}{{\rm{m}}^{ - 2}} \cdot {\rm{s}}{{\rm{r}}^{ - 1}}$
      SNR of infrared detection with traditional optical system15.2/14/12.9
      SNR of infrared detection with diffractive optical system9.7/10.1/10.5
    • Table 5. Equivalent noise power in different systems

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      Table 5. Equivalent noise power in different systems

      Signal time widthEquivalent noise power
      Electronics system0.25 ns$1.6 \times {10^{ - 11}}\;{\rm{W}}$
      Laser system0.25 ns$7.3 \times {10^{ - 11}}\;{\rm{W}}$
      10 ms$1.8 \times {10^{ - 16}}\;{\rm{W}}$
      Infrared system10 ms$6.8 \times {10^{ - 12}}\;{\rm{W}}$
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    Kai Zhou, Daojing Li, Yefei Wang, Yuan Yao, Ming Qiao. Target detection performance of infrared spectrum with diffractive optical system[J]. Infrared and Laser Engineering, 2021, 50(8): 20200371

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    Paper Information

    Category: Infrared technology and application

    Received: Dec. 17, 2020

    Accepted: --

    Published Online: Nov. 2, 2021

    The Author Email: Daojing Li (lidj@mail.ie.ac.cn)

    DOI:10.3788/IRLA20200371

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