Streamlining Pipeline Data Collection with DVSS


Courtesy of Envirosight LLC

Streamlining Pipeline Data Collection Information with Digital Visual Sidewall Scanning (DVSS)

Since the advent of miniature cameras, engineers, contractors and public works officials have used them to assess pipeline conditions and troubleshoot problems.

Over the years, new delivery mechanisms have emerged to carry cameras deeper and deeper into lines, while capturing increasingly better images. Among the most sophisticated of these is the video inspection crawler, which can transport a robotically articulated camera hundreds -- even thousands -- of feet into pipelines to identify corrosion, deposits, foreign matter, cracks, deformations, offsets and erosion.

Although widely successful, crawler inspection still presents certain drawbacks. For instance, under normal conditions, a crawler operators is simply too preoccupied to properly analyze the video a crawler captures. In many instances, the operator isn’t even the person most qualified to make the analysis. Furthermore, those who are best qualified— PACP trained personnel and civil/environmental engineers—seldom have the time to review hours of video footage.

Introducing Digital Visual Sidewall Scanning. Digital Visual Sidewall Scanning (DVSS) relies on the proven inspection crawler platform to gather visual data from within a pipe. However, unlike traditional video inspection, DVSS implements digital image processing to deliver rich information in a format that is easy to analyze.

DVSS relies on software to manipulate video frames into a flat digital scan. This scan resembles a long mural or scroll, and it bears an image whose length corresponds to the length of the pipe, and whose height represents the pipe’s full circumference, from 0 to 360 degrees. These scans capture a level of detail far greater than conventional video, while presenting it in a format that is easier to review and analyze.

Rather than sitting through hours of inspection video, an analyst looking at a DVSS scan can review an entire length of pipe in one glance, quickly pinpointing problem areas and making annotations and measurements directly on the scan itself. Client software presents a thumbnail version of the entire scan (resembling a film strip, as shown) for quick navigation to specific regions of the scan. Drawing and annotation tools allow analysts to mark-up the scan, while identifying pipe features and highlighting regions of concern.

Technology of DVSS.
Ideally, Digital Visual Sidewall Scans are created in real time by a quick-moving crawler. The crawler itself requires only three special features:
• A fish-eye camera lens that provides a field of view greater than 180 degrees
• Diffuse wide-angle lighting
• An encoder for exact measurement of camera movement

As the crawler advances down a line, the encoder fires a signal for each inch of forward motion. With each signal the video camera captures a single video frame and transmits it back to the crawler CCU.

The CCU then digitizes the signal by extracting a ring of pixels corresponding to a one-inch section of the pipe wall. Using a mathematical algorithm, the computer slices this ring at the bottom and unfolds it into a rectangle. As rectangles are extracted from each subsequent video frame, they are stitched together into a complete sidewall scan. Building a good scan in this manner requires ample and even illumination, a camera whose view is centered in the pipe, and minimal terrain variation.

Typical DVSS Workflow.
Because it captures data in an automated fashion and relieves operators of having to analyze footage on the fly, DVSS greatly improves the speed at which inspection can be performed. Furthermore, it allows operators to concentrate on piloting the crawler, since the analysis is left to the appropriate professionals. For this reason, there is no need to slow down at problem areas or articulate the camera to gain a better view. Likewise, there is no need to stop and backtrack when a potential problem flashes by onscreen, or even to second-guess perceived anomalies.

This productivity also extends into the analysis phase, where professionals representing multiple disciplines can quickly survey scans using client software. Presented with a single scan of the entire pipe interior, an analyst can quickly search for areas of interest, zoom in for greater scrutiny, and annotate the scan directly. Because the scan is dimensionally accurate, built-in measurement tools allow for the precise quantification of observations -- like crack length, tap diameter, and corrosion surface area.

Implementing DVSS.
As revolutionary as Digital Visual Sidewall Scanning technology may seem, it remains remarkably accessible. The technology is comparatively affordable, requires no extensive training, and delivers robust, digestible data.

When evaluating DVSS solutions, primary considerations include:

• Real-time versus offline operation. Real-time DVSS is just that—you can view the scan as it is built, and upon completion of inspection the entire scan is immediately available for review by others. The DVSS equipment and operator, meanwhile, are free to move on to the next job. Offline scanning purports to deliver a higher-resolution scan, but typically requires extensive post-processing, which means the scan cannot be viewed as it’s created, nor is it immediately available for review by others.

• Storage bandwidth. As with digital cameras, more resolution is better, but only within practical limits. Ideally, scans should be viewable on a standard computer terminal with a standard video card, easily transmitted via wireless LAN, and readily archived in batches onto CD-R or DVD-R.

• Equipment investment. Some DVSS systems are standalone, which means you must purchase the DVSS camera, computer, and software, as well as a crawler, cable reel, and CCU, plus a vehicle in which to haul everything. By contrast, other DVSS systems are modular, which means the DVSS camera, computer and software can be purchased to retrofit an existing crawler system. These modular systems require substantially less investment. They also offer the versatility of switching between DVSS and standard video inspection, plus they are easier to upgrade.

• Ease of integration. DVSS should complement your current inspection program, not upend it. Make sure the DVSS system you choose integrates with the inspection and asset-tracking software already in use. This means you should be able to link databased observations to regions of your scan, correlate scans to GIS/GPS data, and easily integrate those scans into reports.

Envirosight, LLC , based in Randolph, New Jersey specializes in video pipeline inspection. Their versatile ROVVER and SuperVision video inspection crawlers are known for their exceptional range, maneuverability and portability. The company’s DigiSewer DVSS solution is available for the ROVVER crawler. Envirosight also manufactures the QuickView zoom inspection camera, which carries several zooming patents and patents pending. The company serves industry, municipalities, contractors, departments of transportation, and civil/environmental engineers. The company is committed to ongoing innovation, delivering products that enhance user productivity and improve inspection results. Envirosight supports customers through a worldwide network of extensively trained sales and service partners. All Envirosight technical employees hold NASSCO PACP certification. Visit Envirosight online at

Customer comments

No comments were found for Streamlining Pipeline Data Collection with DVSS. Be the first to comment!