SHUTTER-LESS TEMPERATURE-DEPENDENT CORRECTION FOR UNCOOLED THERMAL CAMERA UNDER FAST CHANGING FPA TEMPERATURE
Keywords: Uncooled Thermal Camera, Fast Changing FPA Temperature, Shutter-less, Temperature-dependent Correction, Radiometric Calibration, FLIR GEV
Abstract. Conventional temperature-dependant correction methods for uncooled cameras are not so valid for images under the condition of fast changing FPA temperature as usual, therefore, a shutter-less temperature-dependant correction method is proposed here to compensate for these errors and stabilize camera's response only related to the object surface temperature. Firstly, sequential images are divided into the following three categories according to the changing speed of FPA temperature: stable (0°C/min), relatively stable (<0.5°C/min), unstable (>0.5°C/min). Then all of the images are projected into the same level using a second order polynomial relation between FPA temperatures and gray values from stable images. Next, a third order polynomial relation between temporal differences of FPA temperatures and the above corrected images is implemented to eliminate the deviation caused by fast changing FPA temperature. Finally, radiometric calibration is applied to convert image gray values into object temperature values. Experiment results show that our method is more effective for fast changing FPA temperature data than FLIR GEV.