| 摘要 |
PURPOSE:To improve SN ratio and to make the execution of profile measurement of high accuracy possible by receiving the poulse laser beam reflected by the surface to be measured with a photodetecting system having a gate circuit operating in response to polses. CONSTITUTION:The laser beam outputted from a pulse laser oscillator irradiates the surface to be measured and the reflected beam thereof is received with an photodetection system having a gate circuit operting in accordance with pulses, whereby the profile of the surface to be measured is measured from the incident and exit angles of the laser. For example, the furnace top part 2 of a blast furnace 1 is irradiated via a reflection mirror 6a and a scanning mirro 7 having an angle encoder by the laser beam L outputted from a laser oscillator 6, and the reflected beam from the irradiation point A is received in a photodetecting system 5. At this time, a photodetector 11 receives the control of a gate circuit 12 operating with delay for a constant time from pulse generation by the signal from an electric power source circuit 15 and performs detection of good SN ratios and therefore the profile of the surface to be measured determined from the incident and exit angles is of high accuracy. |
