| 摘要 |
PROBLEM TO BE SOLVED: To provide an endoscope imaging system capable of extending the life of a light source even for a subject periodically moving at high speed when an image of the subject periodically moving at high speed is taken with pulse emission of the light source. SOLUTION: The periodical movement of the vocal cords is detected by a microphone 10, and a signal component in a prescribed range of frequency is extracted by a sound frequency extraction part 41, etc., and converted to DC voltage on a frequency/voltage converter circuit 43. The converted DC voltage is inputted to a comparison circuit 51 and a voltage shift circuit 44, and compared with a standard voltage Vr on the comparison circuit 51. If a periodical movement is judged, connecting points (a) of switching circuits 49a and 49b are switched on. After the voltage is shifted by a small voltage on the voltage shift circuit 44, the voltage is converted to a rectangular wave with a frequency slightly different from that of the vocal cords on a voltage/frequency converting circuit 45. The wave is divided on a frequency converting/dividing circuit, and two LED's 16a and 16b are made to emit light alternately with two pulses of a frequency half of the frequency of the vocal cords synchronized with the starting edge of the rectangular wave divided from a pulse width/pulse gain adjusting circuit 47.
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