MONITORING DEVICE FOR WELDING ARC PART

摘要

PURPOSE:To obtain a clear picture with eliminating the halation in the arc part by forming the photographic pattern having a low transmission factor on a liquid crystal dot matrix and by extincting the arc part only. CONSTITUTION:The arc generated at a welding arc part 6 comes into a TV camera 5 after passing through a liquid crystal dot matrix 9. The composite synchronous signal obtd. by the camera 5 is led to a matrix control circuit 10 and the brightness in image picking of the video signal obtd. by the incorporated separation circuit is subjected to a bivalent process with the threshold value processing by the prescribed value. An unit liquid crystal plate is motioned with outputting a X axis pulse signal for the LC dot matrix 9 from a X axis pulse generation circuit based on said output. The photographic pattern of the similar shape to the welding arc part 6 having higher brightness than the prescribed value is obtd. for the liquid crystal dot matrix 9 and this part of the photographic pattern has reduced light transmission quantity, so the incident light quantity of the arc part entering the camera 5 is controlled and good picture without any halation is obtd.