Patent ID: 6982412
Filing Date: 2006-01-03
Classification: H04N

Abstract:
1. A method of calibrating an infrared detector using a temperature-adjustable reference surface within its field of view, the method being characterized by the steps of: a) controlling the temperature of the reference surface to a first surface temperature and measuring the output of the detector over a first stare time, the first temperature and stare time being selected so as to achieve a predetermined first well-fill (Wactual) of the detector pixels at the lowest possible temperature of the reference surface; b) processing the output measurements of the detector to obtain a first calibration coefficient (coeff c) adjusting the temperature of the reference surface to a second surface temperature and measuring the output of the detector over a second stare time period (Sactual), the second temperature and stare time (Sactual) being selected so as to achieve a second predetermined well-fill of the detector pixels d) processing the output measurements of the detector to obtain a second calibration coefficient (coeff e) re-adjusting the temperature of the reference surface to a third surface temperature and measuring the output of the detector over the first stare time period, the third temperature being selected so as to achieve the second predetermined well-fill of the detector pixels over the first stare time period; f) processing the output measurements of the detector to obtain a third calibration coefficient (coeff g) adjusting the first calibration coefficient (coeff