| 摘要 |
PURPOSE:To simplify a processing circuit with a reduction ina step signal contained by extracting a temperature change component of a chopper arranged in front of a pyroelectric image pickup element to clamp a heat image signal. CONSTITUTION:Infrared rays radiated from an object 1 pass through an image pickup lens 2 for infrared rays and forms an image on the surface 5 of a target made of a pyroelectric material of a pyroelectric type image pickup tube 6 as infrared image 4. A chopper 3 is provided between the lens 2 and the target 5 to interrupt incident light intermittently whereby an heat image signal 4 is obtained at a terminal of the target 5 as signal varying alternately from positive and negative synchronizing the chopper 3. Then, output signals of the target 5 and a preamplifier 8 are obtained by overlapping a component radiated from the surface of the target with the heat image signal varying alternately from positive and negative synchronizing the chopper according to the chopper temperature. Then, a clamp pulse 19 and a signal component correction signal 18 due to the chopper temperature are applied to a clamp circuit 9. |
