Noise characterization and compensation for a charge-coupled-device-based pyrometer

The pyrometer based on the charge coupled device (CCD) is a cost-effective and widely used system for temperature measurement in various industrial fields. However, due to the inter-element sensitivity deviations of the CCD-array detector and the influence of various types of noise, the digital signal output of the CCD sensor itself is not completely equal to the ideal value as expected. In this work, based on a classical calibration method, the inter-element sensitivity deviations, dark current, shot noise, and readout-quantization noise for a CCD-based pyrometer are characterized, and the influence of these noises on the temperature measurement accuracy is evaluated quantitatively. Furthermore, the non-uniformity correction coefficient for each pixel is obtained by a simple segment correction method to reduce the inter-element sensitivity deviations, and meanwhile, the Kalman filter is introduced to remove the temperature fluctuations caused by these noises. Experimental results show that mean value of the spatial standard deviation of temperature measurement results in the total measurement range (800-1200 °C) is only 2.2 °C after non-uniformity correction, and the temperature fluctuations can be reduced from 26.6 to 1.98 °C based on the Kalman filter.