Observation of a dynamic specular weld pool surface

Observation and measurement of a weld pool surface is a key towards the development of next generation intelligent welding machines which can mimic a skilled human welder to a certain extent. However, the bright arc radiation and the specular surface complicate the observation and measurement task. This paper proposes a novel method to turn the difficulty of the specular surface into an advantage by exploiting the difference between propagation of an illumination laser and the arc plasma. The governing law is simply the reflection law which can provide the base for the computation of the weld pool surface. Experimental results verified the effectiveness of the proposed method in acquiring clear images in the presence of the bright arc.