Edge following up method, detecting method and device

TL;DR: In this paper, the gap between the plates 6 and 7 or between edge passages is estimated from line passage from a projector projecting a line pattern over the edge, a camera picking up the image of the pattern and the image that is picked up is analyzed.

Abstract: PROBLEM TO BE SOLVED: To evaluate an image which is picked up even under each poor condition without problems. SOLUTION: To follow up and check an edge between two metallic plates 6 and 7 to be welded, a projector 2 projects a line pattern 5 over the edge, a camera 3 picks up the image of the pattern 5, the image that is picked up is analyzed and the gap between the plates 6 and 7 or between edge passages is estimated from line passage. In such cases, plural lines which have various light intensities are projected. With this, at the time of image processing of the image that is picked up, even when a reflection characteristic of the metallic plates changes, the edge in the image is not shown too weakly or is not shown by being irradiated too strongly, and the image can be evaluated clearly.