| 摘要 |
PURPOSE:To provide a proper image at all times regardless of the temperature of an object by adjusting the quantity of light to reach a camera by changing a filter to be set in front of the camera corresponding to the radiating temperature of the object. CONSTITUTION:A filter unit 4 is provided between a lens unit 3 of a CCD camera 2 and a steel material P. This filter unit 4 is composed of plural filters 5 for which the transmissivity of light is mutually varied, movable holder 6 for holding the respective filters 5, and slide driving unit 7 for selectively setting any one of the respective filters 5 between the lens unit 3 of the CCD camera 2 and the steel material P by driving the movable holder 6. Since the quantity of light made incident on the camera for photographing is adjusted by changing the filter corresponding to the temperature of the object, in the case of photographing plural objects, the proper images can be always provided even when the radiating temperatures of respective objects are dispersed, and the positions or dimensions of objects can be exactly measured. |
