Imaging a safer future - No2 - August 2018
NEXCO Mobile 360° Imaging System (M360IS)
A Safer, More Intuitive Way of Inspecting Structural Surfaces
NEXCO has developed a new service for inspecting metro tunnel systems. The Mobile 360° Imaging System (M360IS) is a high-resolution 360° spherical video system that allows NEXCO to map structures such as concrete tunnel surfaces. The M360IS renders a VR-view, which enables the user to "walk-through" the stream of high-definition images as if he/she is visually inspecting the site themselves.
Visual inspections can be made faster and safer with the System. Once the M360IS maps the site, either mounted on a vehicle or carried as a backpack, the inspector can examine the video from the comfort of their desk. During tunnel inspections, this feature is especially invaluable since it minimizes the time that inspectors are exposed to potential danger. Once the data set is created, inspectors can identify problem areas on their computers and focus-in on areas that may need further analysis on-site.
NEXCO is currently working to establish georeferencing capabilities for the M360IS which will associate each individual pixel of the image to real-world coordinates. To learn more about the M360IS, click on the link below, or find our brochure in the Downloads section under the News tab.
Driven by our wish to improve the infrared scanning technology, we performed a comprehensive research project in 2014 aiming to analyze which type of infrared camera is more accurate to inspect concrete structures. In this research project, different models of μ-bolometer and cooled sensor infrared cameras were compared to evaluate their accuracy in application to bridge deck scanning.
In the laboratory phase of this research project, stationary infrared images of test concrete pieces were taken from 3 different angles. The resulting images were analyzed using our proprietary software, IrBAS, to assess the efficiency of each camera. It was found that the cooled sensor cameras, especially the InSb ones, detect delaminations better than the μ-bolometer cameras. Even from a 45° angle, the cooled sensor cameras were able to clearly detect delaminations while the μ-bolometer cameras produced false detections. This effect can be easily explained considering that the cooled sensor cameras have a higher sensitivity than the μ-bolometer ones. As a conclusion, in laboratory conditions, cooled detector infrared camera performance was better.
Click on the link below to download the laboratory test research report if you want to know all the details on this project.
In the field tests the cameras were attached to a moving vehicle to perform inspection on Haymarket Bridge's southbound shoulder. The inspection was performed at a constant speed, 30 mph. The locations of defective areas were already known, making the site ideal for testing the capabilities of the cameras. It was found that cooled sensor infrared cameras captured high quality images while μ-bolometer cameras captured blurrier ones. The higher quality of the pictures taken with the cooled sensor cameras result in a better analysis of the data without false detections; however, the blurry pictures of the μ-bolometer cameras provoked some false detections of delamination. This phenomenon can be explained considering that the cooled sensor cameras have a shorter exposure time than the μ-bolometer ones. As a conclusion, in actual field inspections, cooled detector infrared camera provided more accurate detection. The analysis results were also compared with conventional methods like hammer sounding and chain dragging. Although the results were not a perfect match, the detections through infrared images are certainly comparable to conventional methods.
Click on the link below to download the field test research report if you want to know all the details on this project.