Research on the laboratory radiometric calibration of the thermal imager

Zifeng Lu; Qiang Sun; Jian Wang; Zhenwu Lu; Yichun Liu

doi:10.1117/12.865337

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11 October 2010 Research on the laboratory radiometric calibration of the thermal imager

Zifeng Lu, Qiang Sun, Jian Wang, Zhenwu Lu, Yichun Liu

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Proceedings Volume 7656, 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment; 765645 (2010) https://doi.org/10.1117/12.865337
Event: 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies, 2010, Dalian, China

Abstract

The radiometric calibration of the thermal imager was investigated to build the relationship between the input radiance and the digital output to realize the temperature measurement. The radiometric calibration was implemented in the State Key Laboratory of Applied Optics. A standard black body source was served as radiation source. The response of the thermal imager to the input radiance was tested for different gains. The experimental results show that the average grey level of the output imaging is linear dependence of the input radiance. Because the radiance in the receiving wave range of the thermal imager is linear with the black body's temperature based on Planck's law of radiation, the average grey level of the output image is also linear with the black body's temperature after fitting a curve to the experiment data points. Then the relationship of the response and the gain was studied when the black body's temperature kept constant. The preliminary analysis of calibration data shows that the response of the thermal imager is linear and the average grey value of the image is directly proportion to the gain. According to the experimental results, the reference gains and the dynamic range of temperature measurement were obtained. Finally, the uncertainty influencing the calibration results was analyzed, the analysis shows the maximal uncertainty is 5.2%, which can meet the calibration requirement less than 10%.

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Zifeng Lu, Qiang Sun, Jian Wang, Zhenwu Lu, and Yichun Liu "Research on the laboratory radiometric calibration of the thermal imager", Proc. SPIE 7656, 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, 765645 (11 October 2010); https://doi.org/10.1117/12.865337

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