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Accurate visual assessment of the interiors of manholes, boreholes, drilled shafts, or other vertical cavities is essential for efficient planning, maintenance, rehabilitation, and replacement. On-site inspection can be accomplished by lowering a trained inspector into the confined space, but more often requires deployment of a pan-and-zoom pole camera to capture the needed images for onsite or later analysis.
The Panoramo SI 3D Optical Manhole Scanner by RapidView provides an alternative method of inspecting. The system creates a digital 3D visual model of the structure that can be rotated, panned, zoomed, and measured on a computer screen. The Viewer software puts users into the shaft space by creating a fully interactive virtual reality 3D environment based on the digital model.
Images are acquired simply by lowering a special optical scanner to the bottom of the shaft and retrieving it again. Matt Sutton, vice president of sales and marketing at RapidView, guided a demonstration via telephone using a CD with data from a manhole previously scanned. A scanning demonstration was not observed because that process is extremely simple and takes only a few minutes.
RapidView LLC, based in Rochester, Ind., is the U.S. distributor of the system. The manufacturer is IBAK Helmut Hunger GmbH & Co. KG of Kiel, Germany.
Walk-around
The Panoramo 3D pipe inspection system from RapidView was the subject of a Technology Test Drive in the July 2008 issue of Municipal Sewer & Water. “The manhole inspection system was a logical extension of that same hardware and software,” says Sutton. “We just realized that if we rotated the pipe inspection camera by 90 degrees, we’d have the perfect solution for inspecting vertical cavities like manholes.”
The full package includes the camera (3D optical scanner), fiber-optic camera cable, KW505 winch, BS5 controller, and a computer with a sufficiently powerful processor and video card to support the 3D Viewer software.
A community could use an existing computer to trim the cost slightly, but the machine needs to meet the software’s system requirements: Windows XP or Vista, and a fast video card. Since a single manhole generates about 20 Mb of video data, a large hard drive is also required for data storage with any significant numbers of assets.
Mechanically, the heart of the system is the scanner, which uses two opposite-facing wide-angle lenses to image the cavity interior. Each lens has a 186-degree field of view, enabling the system to cover 360 degrees with a slight overlap.
One pair of images is captured for every 2 inches of vertical travel. Illumination is provided by two onboard xenon strobes that produce bright, pure, white light and render colors with high accuracy. Accurate color rendition is essential for the correct identification of asset composition, corrosion states, and biological intrusions.
Images have high enough resolution to allow zooming by a factor of nine, handy for taking a closer look at a bent ladder rung or cracked wall. Images are streamed via fiber optic camera cable to the controller and display. There, the operator can view acquired images in real time, or generate a Panoramo film for later off-site review and analysis by engineers.
The scanner fits any vertical cavity 16 inches or greater in diameter. It is 7 inches long and weighs 16 pounds. It must be lowered by the RapidView winch and controller to move the camera at its design speed of about one foot per second.
The digital magic happens in real time, as visual data is processed by the Viewer software. It stitches the individual images into a seamless representation of the entire cavity interior, providing a “virtual reality” experience that essentially places the operator inside the cavity.
