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5 August 2009 Correction of the non-uniformity of the radiometric detector of WSICMS
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Whole-Sky Infrared Cloud Measurement System (WSIRCMS) is a ground-based automatic cloud measurement equipment. WSIRCMS retrieves cloud from the atmospheric downward infrared radiance (DIR) in the range of 8~14μm. The Radiometric detector of WSIRCMS is made of a 320×240 pixels uncooled infrared focal plane array(UIRFPA) and a large field of view infrared lens which is approximately 47°×64°. The non-uniformity of the detector is caused by the infrared lens and the UIRFPA. The non-uniformity can seriously distort sky radiance image and affect cloud retrieval. A non-uniformity correction (NUC) method is proposed in this paper, which is based on the calibration test of each pixel of the detector. A Wide Field of view Hemispheroidal calibrator(WFHC) is manufactured to test the non-uniformity of the detector of WSIRCMS. Its temperature is controlled by water bath. The equivalent emissivity of the WFHC is determined first. The Each pixel of the detector mounted on the sphere's center of the calibrator can receive equal radiance. Correction coefficient of each pixel of the detector is acquired from the analysis of calibration data and a correction table is made. The result of non-uniformity correction shows that the method proposed can correct the nonuniformity of radiometric detector of WSIRCMS and improve the cloud image quality effectively.
© (2009) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
X. Sun and Jian Liu "Correction of the non-uniformity of the radiometric detector of WSICMS", Proc. SPIE 7383, International Symposium on Photoelectronic Detection and Imaging 2009: Advances in Infrared Imaging and Applications, 73830T (5 August 2009);

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