| 摘要 |
PROBLEM TO BE SOLVED: To provide a hole inspection method in which neither a waterdrop nor a foreign matter sticks to a wide-angle lens provided at a tip of an insertion shaft.SOLUTION: When an insertion shaft 11 including a wide-angle lens 11a at a tip is inserted in a hole to inspect a hole wall surface S based on an image by the wide-angle lens 11a, first gas G1 is injected toward the bottom of the hole along a peripheral face of the insertion shaft 11, and second gas G2 is injected to the direction same as the first gas G1 in the peripheral part of the first gas G1 at a flow velocity faster than the first gas G1. |
