| 摘要 |
PURPOSE:To attain the automatic correction of the variation in the focal length without large-sized device constitution by using two storage elements so as to correct the fluctuation of visual field of an infrared-ray optical system attended with the change in temperature. CONSTITUTION:An infrared-ray irradiated from an object R is collected by an infrared-ray sensor 3 via a vibration type scanning mirror 1 and an infrared- ray optical system 2. A temperature detector 21 detects the temperature of required position of the optical system 2 and sends it to the 1st ROM 23 and the 2nd ROM 24. Correction information of scanning time deviation having a scanning mirror effective vibration amplitude caused by the temperature of a required position is recorded in the ROM 23 with respect to the detection temperature of the detector 21 and the correction information of sampling time deviation in the scanning line time is recorded in the ROM 24. Then based on the correction information of the ROMs 23, 24, the visual field fluctuation of the optical system 2 attended with the temperature change is corrected.
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