Radiometric Calibration and SNR Calculation of a SWIR Imaging Telescope

Yilmaz O., Turk F., Selimoglu O.

2nd International Congress on Advances in Applied Physics and Materials Science (APMAS), Antalya, Turkey, 26 - 29 April 2012, vol.1476, pp.365-369 identifier identifier

  • Publication Type: Conference Paper / Full Text
  • Volume: 1476
  • Doi Number: 10.1063/1.4751629
  • City: Antalya
  • Country: Turkey
  • Page Numbers: pp.365-369
  • Middle East Technical University Affiliated: No


Radiometric calibration of an imaging telescope is usually made using a uniform illumination sphere in a laboratory. In this study, we used the open-sky images taken during bright day conditions to calibrate our telescope. We found a dark signal offset value and a linear response coefficient value for each pixel by using three different algorithms. Then we applied these coefficients to the taken images, and considerably lowered the image non-uniformity. Calibration can be repeated during the operation of telescope with an object that has better uniformity than open-sky. Also SNR (Signal to Noise Ratio) of each pixel was calculated from the open-sky images using the temporal mean and standard deviations. It is found that SNR is greater than 80 for all pixels even at low light levels.