Study on the Extraction method for the Contrast Feature of Ship Wake Images Based on Human Visual Characteristics

Since how to evaluate the ship wake image's quality quantitatively and effectively, and achieve the purpose of the extraction of ship wake's optical signal characteristics rapidly, is an important base task for the ship optics-wakes elimination technology now. The method about quality evaluation of ship wake images is studied in this paper based on the contrast model. According to the characteristics of the obvious contrast between wake area and seawater background area in ship wake images, this paper uses the contrast parameter as the index of wake image quality evaluation, and also as the characterization of the strength of ship wake's optical signal characteristic. In order to evaluate the actual quality of ship wake images, the weighting factors on wake area and seawater background area are introduced in this paper for combination evaluation when the basic contrast calculation model is improving. The improved model can fully consider the human visual characteristics and combine the subjective and objective evaluation methods organically. An experiment about the extraction of contrast feature is also carried out in this paper using the developed experiment device, which especially for the maritime feature extraction experiment. The results of this paper show that the contrast parameters can not only reflect the subjective visual perception of the human eye on the wake images' actual quality, but also better reflect the application essence of the wake image processing. And the contrast parameters can describe the intensity's changing rules of ship wake's optical signal characteristics reliably and quantitatively.