Published December 2007

Video On Demand

By Dan Heim (page 60)

Hard-drive storage improves speed, convenience, efficiency, and reliability for a Tennessee city’s inspection data.

The Water and Sewer Depart-ment in the City of Murfreesboro, Tenn., has made the transition from fragmented VHS sewer inspection tape records to a comprehensive hard- drive-based (HD) video information storage system.

HD storage made sense to Terry Taylor, operations superintendent. Murfreesboro is a fast growing area, and with many pipes still being inspected for the first time, Taylor’s department was looking for the fastest way to catch up.

The Cobra Information Manage-ment System (CIMS) relational database system from Cobra Technologies is helping. “We used to have videotapes of just a few sections in the sanitary system, but now we’re quickly getting all our pipes recorded, including laterals,” Taylor says.

Great strides

The technology is an example of how far inspection technology has come. There was a time when the only images of pipe interiors were Polaroid photographs. The first inspection cameras recorded to videotapes, which were supplanted in the late 1990s by CD/DVD storage systems. Hard-drive storage is the latest leap forward.

The cost of hard-drive storage has plummeted. One gigabyte (GB) of capacity — equivalent to 500,000 pages of text — now sells for about $5, versus $100 a decade ago. Today’s buzzword is “terabyte” (TB), which is 1,000 GB. With this much space available at low cost, hard-drive storage makes sense, especially when it eliminates the storage and cataloging of CDs or DVDs and allows multiple users instant, simultaneous access on network platforms.

The CDL 9000 Data Logger compresses raw video to an MPEG-1 format with a bit rate of 1.15 MB/s (10 MB/minute). Resolution is 352 x 480 pixels at 30 frames per second. Capture is done in real-time, via a dedicated hardware-based compressor built into the Cobra Data logger installed in the inspection van.

MPEG-1 accurately captures the detail provided by typical survey cameras, says Alan Grant, Cobra CEO and national sales manager. Cobra provided Murfreesboro with the custom servers needed to store all its video data. “We purchased a separate 1.2 TB server to hold the video, and I’ll probably up that to 4.2 TB at some point,” says Brian Pollock, the city’s IT coordinator.

Miles of pipe

One single terabyte can hold video data for one million feet (190 miles) of pipe. The servers use RAID 3+0 (Redundant Array of Independent Drives) to preclude the need for data backups. RAID employs multiple hard drives to store the same data. With this redundancy, only a simultaneous failure of multiple drives could cause data loss.

On the field input end, field units can be equipped with a fingerprint ID logon to ensure that only trained and authorized operators can access the system. “Engineers like this added security, since it ensures that the data is entered by a certified operator,” says Grant. That is part of what NASSCO is trying to promote with the PACP Standard.”

Integration of the Cobra system was easy for the city, says Pollock. “If you’re computer literate, it’s routine work,” he says. “I just set up our access groups, mapped the network drives, and we were up and running.

Work is also going well in the field. “Our guys really like the system,” observes Bill Kemp, rehabilitation foreman. “They used to keep paper records, but this digital system is a lot better. Plus, the user interface is simple. I wasn’t computer literate, but it was very easy for me to learn. I started using it right away.”

The department still has a library of VHS tapes from the early days but expects at some point to convert them to MPEG-1 for transfer to hard drives. The ease with which video files can be located and searched makes other storage systems seem archaic.

Says Taylor, “When you need to look at a video, the speed of this system is just amazing. It’s saving us a lot of time and makes it easier to do our job.”