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Multiple ship tracking (MST) is an important task in marine surveillance and ship situational awareness systems. Considerable work has been conducted on multiple object tracking in recent years, but it has focused primarily on pedestrians and automobiles, leaving a gap in studies on MST due to the particularities of complex marine scenes, such as ship scale variations, the long-tailed distribution of ships, and long-term occlusions caused by ship movements. In this article, we present a robust deep affinity network (RoDAN) for MST. To overcome the above difficulties in MST, we start with the basic deep affinity network (DAN) and improve it in three aspects: scale, region, and motion. For the scale dimension, we integrate an atrous spatial pyramid pooling (ASPP) module to improve the modeling ability for multiscale ships. For the region dimension, we propose the joint global region modeling (JGRM) module, which further strengthens the modeling ability of DAN and exploit it to overcome the long-tailed distribution property of ships. For the motion dimension, we propose the motion-matching optimization (MMO) module to fine-tune the tracking results and make our tracker more robust, less reliant on the front-end detector, and ameliorate long-term occlusions. The experimental results demonstrate that our MST method outperforms the state-of-the-art methods. In particular, it reduces the number of ID switches (IDSs) and trajectory fragmentations (FMs), achieving holistically preferable performance. Meanwhile, our method achieves a comparable speed.

Ship segmentation is an important task in maritime surveillance systems. A great deal of research on image segmentation has been done in the past few years, but there appears to be some problems when directly utilizing them for ship segmentation under complex maritime background. The interference factors decreasing segmentation performance usually are from the peculiarity of complex maritime background, such as the existence of sea fog, large wakes and large waves. To deal with these interference factors, this paper presents an integrated ship segmentation method based on discriminator and extractor (ISDE). Different from traditional segmentation methods, our method consists of two components in light of the structure: Interference Factor Discriminator (IFD) and Ship Extractor (SE). SqueezeNet is employed for the implementation of IFD as the first step to make a judgment on what interference factors are contained in the input image. While DeepLabv3 + and improved DeepLabv3 + are employed for the implementation of SE as the second step to finally extract ships. We collect a ship segmentation dataset and conduct intensive experiments on it. The experimental results demonstrate that our method for ship segmentation outperforms state-of-the-art methods in terms of segmentation accuracy, especially for the images contain sea fog. Besides our method can run in real time as well.

This paper presents a method that the algorithm of calculating the electric field combining with vector electric field multi-electrode gradient information is optimized by using the compression-aware greedy reconstruction algorithm, which can effectively identify the electric field gradient information and improve the accuracy rate of the voltage level detection judgment, through the research on the calculation method of the electric field gradient information of the electrical equipment in the substation. This method can accurately calculate the electric field distribution and voltage level around the high voltage conductor by analyzing the electric field information around the charged body. The distribution of the field strength at one interval of the charged carrier is obtained by tested in complex power frequency electric field environment of the 110 kV substation equipment. The results show that the method can effectively improve the detection capability of the voltage level of the charged carrier and the response speed of the electric field around the charged body, and improve the safety of the staff working in the complex electric field.