Digital Visual Sidewall Scanning: Streamlining Collection And Analysis Of Inspection Data

Since the advent of miniature cameras, plant and utility personnel have used them to assess pipe condition and troubleshoot problems. Over the years, new delivery mechanisms have emerged to carry cameras deeper and deeper into pipelines 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.

However, as successful and widespread as crawler inspection has become, its main drawback remains the issue of operation vs. analysis. Under normal conditions, an operator is too preoccupied driving a crawler to properly analyze the video it captures. In many instances, the operator isn’t even the person most qualified to make the analysis. Those who are best qualified - metallurgists, process chemists, structural engineers - seldom have time to review hours of video footage which may still fail to deliver sufficient detail of problem areas.

Ultimately, the dilemma is one of presentation - crawlers need to capture rich visual data in a manner independent of operator judgment and present it in a way that allows efficient review by those best qualified to make an analysis.

Responding to this need, Digital Visual Sidewall Scanning (DVSS) provides an extremely reliable method for gathering visual data from within a pipe using the proven crawler platform. But, 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 bears an image whose length corresponding to the length of the pipe and whose height represents the pipe’s full circumference, from 0-360 degrees. These scans capture a level of detail far greater than conventional video, presenting it in a format easier to review and analyze. Rather than sitting through hours of inspection video, an analyst can review an entire length of pipe at a time, quickly pinpointing problem areas, then making annotations and measurements directly on the scan itself.

This review is aided by special client software presenting a thumbnail version of the entire scan (resembling a film strip) to enable quick investigation of specific scan regions. When an area of the thumbnail is clicked, a detailed view of that region appears in the analysis pane, and a corresponding down-pipe view appears alongside it. In these panes, the analyst can scroll the view in either direction and zoom in on specific regions. Drawing and annotation tools allow the analyst to mark up the scan, identifying pipe features, highlighting regions of concern, and posing questions to subsequent reviewers.

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: