Down the Tube

The Panoramo SI 3D optical manhole scanner brings a “virtual reality” experience to the routine task of inspecting manholes and other vertical cavities

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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.

 

Operation

A single average-depth manhole can be scanned in less than four minutes. The scanner is simply lowered to the bottom of the manhole and activated by the controller. It then rises at a controlled rate, taking a pair of still images for every 2 inches of vertical travel. That translates to a productivity of 50 to 75 manholes per day versus the 10 per day that is more typical using manned entry.

 

The scanner need not be exactly centered in the cavity. The optics provide clear images from surfaces as close as 2 inches, and so as long as that margin is maintained, the camera can be anywhere inside.

 

An internal gyroscope functioning as an accelerometer is used to acquire positional data needed to create the 3D model. Over-lapping visual data from the two cameras is then triangulated to set the spatial scale of the model. The gyro is not required for leveling — that is taken care of by the support cable and gravity.

The Viewer software first creates a 3D spatial point model (Figure 1) using data from the scanner. If needed, that point model can be exported as an AutoCad (*.dxf) file, from which a wire frame can be meshed.

 

Next, the point model is processed as a grid on which to overlay camera images, creating the visual model (Figure 2). Later, when the Viewer is launched, it draws the required images from that database to create the 3D model.

 

All views are fully interactive, allowing the user to zoom, pan, rotate, measure, and annotate according to standard NASSCO inspection templates. Sutton notes, “The visual data is of such high quality that anything you could see by actually being in the manhole, you see just as easily onscreen.” ­

 

Visual data can be viewed and used on site, but it is typically transferred to the engineers responsible for assessment and analysis in an office setting.

 

Observer comments

With the software launched, the user’s immediate impression is that of indeed being inside the manhole. The functionality is similar to what is experienced when using the 3D viewers provided by many resorts and realty companies to move around inside rooms or buildings. With the motion controlled by either mouse or shortcut keys, the user quickly develops an intuitive feel for the interface.

 

The user also has control over image brightness and gamma, both of which need to be adjusted to best match the type of monitor used for viewing. At any point, individual images can be saved to disc or sent to a printer. Of particular note is the option for an unfolded view (Figure 3), where the entire manhole interior is unrolled from its cylindrical or rectilinear shape into a flat 2D image. Size and distance measurements are easily accomplished with a few mouse clicks.

 

Supplier comments

The Panoramo SI was designed from an engineer’s perspective, and is designed to represent the best engineering solution to the problem of efficiently and accurately acquiring visual and geometric pipe and cavity data, Sutton notes.

 

If the Panoramo SI is purchased in Europe, IBAK provides its own data logging software to serve as an integrated database. That software is not available in the United States. Without it, it is still possible to use the system, but it requires two windows open on the monitor: one for the actual image (observing defects and taking measurements), and the other for logging data manually in a database. “This is by no means difficult,” says Sutton, “but there’s an easier way, thanks to third-party developers.”

 

The flexidata software program from PipeLogix integrates with the Panoramo SI, displaying images, numerical data, and comments in a single window. “What actually happens is that the flexidata software integrates with the IBAK software, storing the images generated by the IBAK scanner and making them available to the user for condition rating the pipe,” says Joan Stone, president of PipeLogix.

 

“The database is available in NASSCO format, so most operators will already be familiar with its layout. Features have been added to take advantage of the survey detail available from the 3D model to make entering the condition assessment fast and easy.”

 

Pipelogix was the first third-party developer to integrate its data-logging software with the Panoramo SI. Sutton says RapidView is seeking to integrate with other third-party developers as well.



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