| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and device which is capable of reliably detecting a bare metal position of a slab even in the case that it is difficult to preliminarily recognize a distance to the bare metal position in an end surface of the slab and to install an imaging apparatus.SOLUTION: A surface of a slab 60 having a deposit is irradiated with laser light, reflected light I is received, and distances L from a light projection position FP to a plurality of reflection positions TP and reflection intensity rates R of the reflected light I at the reflection positions TP are calculated. They are stored in association with each other, a reflection position TP where the reflection intensity rate is a threshold for determination of the position of the deposit, or higher is determined as the position of the deposit, and a reflection position TP where the reflection intensity rate R is lower than the threshold is determined as a bare metal position of the slab 60. |
