The successful tenderer was Veolia Network Services and the equipment supplier was Austeck Pty Ltd.

The first opto-scanner prototype was delivered to the market in late 2001 and officially launched during the IFAT Exhibition in Munich, Germany in May of 2002. At the time it represented a huge leap forward in data acquisition and processing as well as overall contract deliverability and serviceability. Today the system is still unsurpassed in virtually every capacity and is still, as the Yarra Valley Water (YVW) case study will demonstrate, as impressive with its delivery now as it was with its promise nine years ago.

This article examines opto-scanning as a technology, including statistics relating to Panoramo’s performance during the Yarra Valley contract. It draws on data supplied from the contractor responsible for delivering the contract, as well as from YVW.

The concept The approach that opto-scanners take is quite unlike anything YVW has seen before or since. It is a unique idea that gives the viewer complete control of the survey, whether in the field or back in the office, and allows the complete resource of information to be handled in any way long after the survey is complete.

The defining difference of the scanner is that it uses fixed-focus, high-resolution digital photo cameras instead of a conventional video camera. There is one camera placed at each end of the transport unit, or crawler, each with a wide-angle (fish-eye) lens and high-power Xenon flash.

The unit traverses up or down the pipe at 350 mm per seconds taking high resolution digital snap shots at 50 mm intervals – seven shots a second at each end. The exposure rate is 0.0005 of a second, some 80 times faster than conventional CCTV systems, which ensures that the images retained are always crisp and clear. A fibre-optic umbilical is used to convey the images back to the control console eliminating data loss and signal boosting requirements. The unit doesn’t stop or slow down at any point along its journey.

Due to the fish-eye lens, each shot is hemispherical (360 degrees circumferentially around the pipe and 185 degrees longitudinally down/up the pipe)and, once run through the 3D software, the images are collated to give a complete 360 x 360 degree sphere. These spheres are then digitally processed into a ‘film-like’ sequence that is presented in a continuous virtual reality stream allowing the viewer to examine the pipe whichever way they like, at any point in the survey.

Unlike other systems, the scanner enables the viewer to examine the entire internal wall of the pipe including every feature and every defect within it. It records each detail from all possible angles without the need to stop, pan, tilt, focus or interact in any way. After a single pass the survey is complete with everything retained in the digital file format making it available for manipulation or interrogation in the future.

The pipe can be illuminated, rotated and traversed upstream or downstream. Defects can be zoomed in on, viewed from every conceivable angle, and multiple sections can be viewed simultaneously, enabling measurements and observations to be executed with unprecedented speed and accuracy.

One of the many attractive features of the system is that the pipe can be ‘unwrapped’. This feature effectively cuts the pipe along its length, either at 12:00 or 6:00, and lays it out in a two-dimensional format. This allows utilities such as crack width measurement, at-a-glance defect identification and pixel recognition defect analysis to be performed with precision.

Yarra Valley Water case study YVW provides water supply and sewerage services to a population of approximately 1.6 million people across the eastern and north-eastern suburbs of Melbourne – an area exceeding 4,000 square kilometres. This includes management of 9,100 kilometres of water mains.

Gravity sewers owned by YVW range in size from DN150 mm to DN1,800 mm and are constructed from a variety of materials including concrete, earthenware/vitrified clay, cast iron, steel, asbestos cement, PVC and polyethylene. The oldest sewers still in operation were constructed in 1901 however the average age of sewer assets is approximately 60 years.

A vital asset management tool comes of age

CCTV inspection of sewers has been used as an important asset management tool for almost 30 years. The Panoramo camera has provided a significant advance in the quality and useability of YVW’s CCTV records. For the last three years, YVW has used this camera on all programmed inspections their main and branch sewers of DN225 and larger.

The Panoramo program has been increased each year since its beginning in 2006 with 280 kilometres completed and another 540 kilometres planned over the next four years.

The program includes locating, assessing and reporting on condition and features in accordance with WSAA Conduit Inspection Reporting Code. This has resulted in the identification of 215 sewers with a structural grading by peak of rating 5, and 235 sewers with a structural grading by peak of rating 4.

Improved productivity in the field

The operator of the Panoramo camera is not required to code the findings or stop the camera to examine faults or features. The camera is driven straight through the pipe, increasing the length of main that can be surveyed in a shift and reducing the inconvenience to customers by minimising the time spent on their properties. The coding is then done in the office by an operator who is not under the pressures and inconveniences of the field, resulting in a higher quality and more detailed report. Using the data now…and storing it for the future

YVW has found that the great advantage of the Panoramo camera is that it surveys the complete pipe. This means that anyone viewing the data – wherever and whenever – can focus in on any area of the pipe. They are not dependant on what the camera operator chose to focus on or inadvertently skipped over.

Users can also use tools in the ‘unwrapped’ view to specifically identify the location of any defects or fractures, and measure them.

All the data is stored in the Hansen Asset Management System. This eliminates the need for tapes, DVDs and paper records which take up storage space and can be lost. It also provides a full historical record of each line, as well as detailed inspection reports, films and photos. This data is easy to access and compare, and readily available to all relevant areas of the business – including planning, maintenance, and asset rehabilitation – both now and in the future.

Conclusion

Opto-Scanners, such as the Panoramo Camera are a significant advance in CCTV technology. Yarra Valley Water’s use of this technology has enabled the company to prioritise its sewer rehabilitation program with confidence and store a complete condition record in a way that is easily retrievable for future comparisons.