Failure detection system for optical system

Abstract

Abstract PURPOSE:To detect a failure of the entire optical system with high accuracy, by storing a reference background waveform in advance, and comparing the stored data as a threshold value with a video signal at present. CONSTITUTION:When no original exists in a reading position and the output of original detectors 18, 19 goes to H level, the output of an AND circuit 24 goes to H level and this device is set to a state for the failure detection. A binary circuit 9 reads out a reference background waveform value stored in advance from a memory 10, a comparator 11 compares the value with a present reference background waveform obtained via an amplifier 8 and discriminates whether or not the optical system is in failure. When the level of the video signal waveform obtained from the optical system is lower than the threshold level, a failure signal is outputted from the comparator 11. Through this system, failures of the optical system such as deterioration of fluorescent lamp 1, frosting, dirt of lens and dirt of reflection plate 5 is detected.

Inventors

• 👤 Yasuo Inoue
• 👤 井上　保男
• 👤 Haruyoshi Komiya
• 👤 小宮　治義

Bibliographic Details