Tuesday March 12, 1996
Riggers raise glasses to 3-D TV
By Ross Storey |
| Mr Woods' underwater 3-D camera . . . destined for the industrial market. - Picture: Ross Swanborough |
The system, believed to be a world first, has been developed to be used with underwater remotely-operated vehicles (ROVs) in the offshore oil industry. Woodside Petroleum has successfully trialled the camera at the North Rankin gas production platform, off Western Australia's north-west coast. A further trial has been carried out in underground mines, giving operators a three-dimensional, almost real-life view of dangerous mine shafts.
An electronics and research engineer at Curtin University, Mr Andrew Woods, says the system has been under development since he took on the project for his engineering degree in 1988. Mr Woods admits to having been obsessed with 3-D video since he saw the movie Jaws in 3-D format when he was 15. An early prototype of Mr Woods' system used liquid-crystal shutter glasses, and a standard television, but suffered from a flickering screen.
He doubts his system would have broad application in general entertainment. "High-quality 3-D TV technology is quite expensive - certainly out of the range of the normal consumer market," he says. "For the industrial market, however, which can benefit financially from the demonstrated safety and efficiency improvements, the cost isn't much."
Curtin University has recently completed the development of a compact, underwater 3-D camera. The latest prototype weighs about 3.5kg, compared with the initial version's 25kg. It performed well for shipboard operators of ROVs at North Rankin last September, and will return there soon for more extensive trials. The stereoscopic camera system was mounted on the front of the Triton ROV on a pan-and-tilt system and used at a depth of 125m around the base of the North Rankin platform, about 140km off Karratha.
The system comprises a camera (which can also be switched to normal 2-D operation), and a flicker-free display monitor which the operators view in 3-D by wearing lightweight polarised glasses. The stereoscopic camera is actually two video cameras mounted side by side in a compact, robust unit and alignment to provide separate images for the left and right eyes.
"The advantage of being in a one package is that the offshore environment is very hostile," Mr Woods says. "It is very easy for equipment to be damaged, so the more robust and self-contained you can make it, the longer it will last. The alignment of the two cameras is ultra-important. If they were in separate housings and they were knocked, this could totally ruin the 3-D effect."
The camera signals pass through a frame doubler box which digitises the incoming video signal and doubles the display rate to 100 images a second, or 50 images an eye a second. This means the 3-D images are displayed flicker-free. Most standard televisions display 50 images a second, but the latest "flicker-free" sets display 100 images a second. The stereoscopic display screen is fitted with a special liquid-crystal screen - originally produced by the US company Tektronix - which polarises left images with clockwise polarisation and right images with anti-clockwise polarisation. The screen is viewed through special polarising glasses which look like normal sunglasses. Mr Woods says one lens in the glasses is polarised in a clockwise direction and the other in an anti-clockwise direction.
The result is dramatic 3-D colour TV pictures that appear to bulge out of the screen and enable a dramatic improvement in perception of depth, perspective and distance.
- More information:
- Stereoscopic Video Products
- Contact Andrew Woods.
