| 摘要 |
PURPOSE:To prevent the occurrence of errors in detected values, by setting a counting part for a run length for every scanning line in an image pickup device only in the interested region. CONSTITUTION:A molten metal part 2a and a molten metal injecting part 3a of fused steel 2 are scanned by the pickup device 8. The image signal from the device is imparted to a binary coating circuit 15. The signals for molten metal part 2a and the molten metal injecting part 3a are made to be a 1, and the signals for a background part is made to be a 0. The output signals from the circuit 15 are inputted to a counter 17 through a sampling circuit 16. The counting is started by the control signal from a timer 19. The counting is stopped by the control signal from a timer 20. The timer 19 generates a signal which is continued for a preset time period T1 which is set by a variable resistor 22 in response to the fall of a asynchronizing signal from a horizontal signal generator 21. The timer 20 generates a signal which is continued for a preset time period T2 through a resistor 22 by the same way. The counted value of the counter 17 is latched by a register 25 in response to the signal from a strobe signal generator 24. The liquid level 5 is detected from the run length (counted value). Therefore the errors in the detected value can be prevented. |
