Fiber Optic Specklegram Sensor Based On Image Processing Using LoG Filter
In fiber optic sensors, laser source produces a
coherent light which is transmitted through a fiber cable. The
output of this laser forms a speckle. This speckle is captured by a
CCD and then analyzed by a PC. The intensity and shape of the
speckle change when external force is applied on the cable. In this
paper, Laplacian of Gaussian (LoG) filter is used to improve the
dynamic range and accuracy of the fiber optic sensor. Capturing
images is done in a dark room and the simulation is done by
Matlab. The difference between the intensities of a normal and
abnormal state image was 4.0556 when using 2D Discrete Wavelet
transform (DWT) filter. It is increased into 14.6191 when LoG
filter is used, thus increasing the dynamic range and accuracy of
the sensor. In addition, the time is decreased by about 24.5 %. The
number of changed blocks is increased by about 22 % leading to
double increase in the accuracy and dynamic range
KeyWords
speckle imaging; fiber optic sensors; image
proccesing; fiber specklegram; LoG filter
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