| 摘要 |
PURPOSE:To always perform a detection at a fixed operating point even if a temp. of a body to be detected is varied, by photodetecting radiation heat by an optical fiber consisting of plural cores, and processing arithmetically the photodetected output due to a space filtering principle. CONSTITUTION:When the radiation heat 2 emitted from a moving body 1 to be detected is entered into a detecting view field 3, an image is formed by a condenser lense 4 at a photodetecting part end surface 5 of an optical fiber in which seven cores are arranged spatially. The image is transmitted to photoelectric element groups 7 through a cable 6 to generate an output corresponding to the temp. of the body 1. Owing to a method of space filtering, a core output of the center in said output is amplified by amplifier groups 8 by the magnification six times that at the circumference, core outputs of circumferential 6 cores are added by an adder 9, then the difference between said core outputs the center core output is obtained by a difference device 10. Thereby, a space filter signal is obtained, and a stable detecting signal is generated from a position signal generator 12, by detecting by a zero point detector 11 a zero cross point where the photodetected quantity of the center core becomes zero. |
