| 摘要 |
PURPOSE:To eliminate the need for a power circuit for generating a reference voltage and to simplify the hardware by calculating an exposure time from the quantity of exposure converted by an exposure quantity converting means and the output value of an integral state value converting means. CONSTITUTION:The reflected light from a subject 100 is converted by a photoelectric converting means 15 into an electric signal, which is integrated by an integrating means 16 to output an integral state value. A converted exposure quantity storage means 53 is stored with plural exposure quantities for a photographic surface as converted exposure quantities which are converted into real number values respectively. The integral state value which is outputted by the integrating means 16 is converted by the integral state value converting means 60 to the same scale with the converted exposure quantity. Then a lighting control means finds the exposure time from the converted exposure quantity and the output value of the integral state value converting means 60 and the supply time of illumination light from a light source 40 to the endo scope is controlled according to the exposure time. Consequently, the reference voltage for setting the exposure quantity need not be generated, so wide-range photographic conditions (exposure quantity) can be complied with by the simple, inexpensive hard ware. |
