Engineering news
Researchers from the École polytechnique fédérale de Lausanne in Switzerland have increased the precision of optical fibre measurements 100 times by applying graphics processing techniques found in Photoshop.
The use of fibre optics for monitoring the condition of structures, such as bridges or gas pipelines, has increased recently as engineers seek to improve maintenance regimes. The technology measures the path of light within optical fibre up to 100km long. Software algorithms assess deviations in the light to work out information about temperature pressure and the intensity of magnetic fields along the length of the fibre.
However, according to the researchers from the École polytechnique fédérale de Lausanne (EPFL) Group for Fibre Optics (GFO), the method is now reaching its limits with engineers having to sacrifice length, accept a lower resolution or add more equipment, which increases costs.
Measurements made this way have to be processed because they include “noise” that interferes with the signals. The ratio between useful signals and noise cannot go below a certain threshold, or the measurements become unreliable.
The EPFL research team were able to significantly boost this ratio by using technology from the graphic arts field. Luc Thévenaz, director of the GFO said: “The values collected from these measurement points on the fiber can be represented as a matrix of pixels - a two-dimensional image.
"By applying standard graphic filters to this image, like those found in Photoshop, we were able to reduce the noise inherent in this measurement technique very effectively and identify the desired values more precisely."
The work makes it possible to maintain an extremely fine resolution when the fibre gets longer and to process more complex measurements, which account for several parameters.
Thévenaz said the research brings the field of distributed optical optical fibre sensors into a “new era” by using software techniques.
"We have no trouble getting a million measurement points from one optical fibre the width of a hair, for a resolution of one centimeter over 10 kilometers. That's 100 times more precise than current techniques,” he added.