| 摘要 |
PURPOSE:To compensate drift of temperature and that of elapsed time by controlling so that an output of an image sensor at the time of measuring a reference light source in addition to a body to be measured is regulated to the value corresponding to the output from the reference light source. CONSTITUTION:An output e1 of an image sensor 3 at the time of measuring a body to be measured 1 and a reference light source 1a is supplied to an AGC circuit 5 through an amplifier 4. Further, only an output e2 corresponding to the source 1a is sample-held by a sample holding circuit 6 and the gain of the circuit 5 is controlled so that said output e2 is regulated always to the value corresponding to an output ec from the constant light source 1a and the compensation for all outputs e1 of the sensor 3 is carried out. Moreover, these actions are performed smoothly by a transformer 8 and a controlling circuit 9 and the output subjected to the sensitivity compensation is outputted from an output terminal 10. Hereby, the highly accurate output is always obtaind. |
