| 摘要 |
<p>A shutter 3 which can be momentarily held open and immediately closed, is disposed adjacent to an aperture stop 4 in an optical system, and a temperature sensor 5 is provided for measuring the temperature of the shutter 3. The blades of the shutter 3 can be utilized as a reference heat source. With the shutter 3 disposed adjacent to the aperture stop 4, the optical equivalence in the case when a reference heat source is inserted and in the other case, is not spoiled. A shutter 202 which can be readily momentarily held open and immediately closed under control of a shutter controller 203, is disposed at the optical pupil position of a combination lens 201. When the shutter 202 is closed, thermal image data is stored in a shading memory 208. The shading data stored in the shading memory 8 is subtracted for each image element in a subtracter 207 from thermal image data, which is obtained by picking up external infrared image in the open state of the shutter, and the resultant difference data is outputted to a frame memory 209. <IMAGE></p> |
