溢油探测.pdf

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INTERNATIONAL INSTITUTE FOR GEO-INFORMATION SCIENCE AND EARTH OBSERVATIONAutomated oil spill detection with ship borne radar
ABSTRACT
This research outlines the need for a real-time, a ship borne radar facility SHIRA for the tracking of
nearby oil spills during oil containment and cleaning operations at sea with high quality imagery.
SHIRA is imaging digital X-band radar, developed by TNO for the measurement of oceanographic
features. It was especially adapted for the imaging of oil slicks by implementing a number of im-
provements, based on the outcome of a previous oil detection experiment. The main aspects that make
SHIRA suitable for the current purpose are its high sensitivity and dynamic range, and its ability to
integrate a large number of images of the same scene, after correction for platform motions.

Quantitative comparison has been made between various filters, which are able to reduce variance in
homogeneous areas, preserve edges and lines, suppress point scatter, and preserve spatial variability,
while avoiding artefacts. Gamma Filter yields the best smoothing and despeckling. Moreover, it seems
to keep the edges without blurring the minimum. Eight textures are applied, based on the co-
occurrence matrix. These textures include mean, variance, homogeneity, contrast, dissimilarity, en-
tropy, second moment, and correlation. Co-occurrence measures use a gray-tone spatial dependence
matrix to calculate texture values. This is a matrix of relative frequencies with which pixel values oc-
cur in two neighbouring processing windows separated by a specified distance and direc