Abstract
Patterns on manhole covers prevent the slippage of pedestrians and vehicles that go over them. Owners of manhole covers inspect and repair manhole covers when their patterns wear down due to vehicle traffic. It is necessary to introduce efficient inspection methods and improve wear resistance of the patterns on the large number of manhole covers in Japan. We proposed an efficient method that uses image processing to inspect manhole covers. However, since the patterns are only a few millimeters deep, high-resolution images must be captured by placing the manhole cover with high resolution equipment.
We propose a novel pattern for manhole covers. The wear of this highly durable pattern is easy to judge in low resolution images. The shape of the pattern changes as wear increases. We experimented to confirm the pattern's high durability and proposed an algorithm that uses Hough transformation processing to detect wear in patterns.
