A joint research group of NEXCO Central Japan and the Graduate School of Information Science and Engineering of the University of Tokyo has succeeded in developing a technology to detect cracks with a width of 100 mm while traveling in a tunnel at a speed of 0.2 km / h. Aim for introduction in 2018.
Currently, tunnel structures are inspected once every five years by traffic regulation, and by using aerial work platforms, close-up visual inspection, tapping sound, and palpation (detailed inspection).In response to this situation, in order to improve the reliability of inspection technology and reduce costs, technology has been developed to automatically detect deformation by image processing during high-speed driving.
Blurring (motion blur) in camera shooting causes deterioration of image quality.Generally, methods such as image stabilization, flash, and exposure time limitation are used, but inspections for infrastructure maintenance and management purposes require high-speed moving shooting in a vehicle and high-precision image judgment.Taking high-resolution images without motion blur was an extremely difficult task, he said.
Using the "high-speed image processing technology and high-speed compact rotating mirror" researched and developed by the University of Tokyo, we conducted verification toward the practical application of motion blur compensation technology through multiple field experiments.As a result, motion blur can be removed by imaging from a moving object at a speed of 7 km / h against a ceiling 100 m high from the ground in an actual tunnel, and the subject (damage such as cracks) is captured in the center of the screen even while moving at high speed. It became possible to continue control.In addition, the illuminance required for shooting can be reduced compared to the past, so the size of the shooting device has been successfully reduced.In addition, because traffic restrictions are not required, inspection costs can be expected to be reduced.
With this technology, the inside of the tunnel is photographed in advance, and the inspection is carried out after grasping highly accurate information in advance, in order to improve the reliability and efficiency of the inspection.