| 摘要 |
A system for calibrating a thermal imaging system comprising an array of pixels forming for example a Focal Plane Array (FPA) 4. The calibration system comprises a passive shutter or paddle (3, Fig.1) that can be moved in and out of the optical path between a first 3a and second 3b position. When the shutter (3, Fig.1) is in the optical path of the imaging system, an image of the shutter surface, which is flat and uniform, is generated. The shutter is heated whilst in the second position 3b by for example a suitable LED 7 and then returned to the first position 3a. A further image of the heated shutter is then generated. The data sets generated at the two different temperatures enable the image generated by the imaging system in normal use to be to be adjusted for responsivity and variation in DC offset of the specific pixel array. The first temperature may be ambient temperature. The shutter blade may be partially reflective to allow the shutter to appear to be at a lower temperature when placed in front of a cooled infrared detector. The shutter may be moved by a suitable shutter motor drive (5, Fig.1). |
