Detecting migrant vessels in the Cyprus region using Sentinel-1 SAR data

Abstract

Remote sensing is considered as an increasingly important technology for maritime surveillance. The process of maritime surveillance for safety is critical for every country. The need for information on migrant movements by sea using different sizes and types of vessels is of paramount significance. Such information is essential for the search and rescue (SaR) operations of unauthorised migrants. The aim of this paper is to show how to detect migrant vessels in the Cyprus Region using freely available Sentinel-1 SAR data. The comparison was made using open source available migrant data and Sentinel-1 SAR acquisitions. Sentinel-1 SAR images were used to investigate three Areas of Interest (AoI). The main AoI is located at the Northwest coasts, whilst the second area includes the Southeast coasts of Cyprus. The results indicate that the Sentinel-1 SAR data can provide decisionmakers with effective results and spatial information on migration routes.

Ship detection using SAR images based on YOLO (you only look once)

“…The results show that the objects are detected in satellite images as follows: Area of Interest 1 (AoI-1) on 19 November 2022 at 15:50 (see Figure 4), AoI-2 on 26 November 2022 at 15:41 (see Figure 5), and AoI-3 on 02 December 2022 at 03:51 (see Figure 6). In SAR images using SNAP viewer, ships appear bright pixels in a darker local background [7]. We can see the promising targets (ships) shown within the red circles [7] (see Figures 4,5,6) in the Areas of Interest.…”

“…Using the ocean object detection tool in SNAP, ships are extracted from Sigma Nought VH [7]. The results show that the objects are detected in satellite images as follows: Area of Interest 1 (AoI-1) on 19 November 2022 at 15:50 (see Figure 4), AoI-2 on 26 November 2022 at 15:41 (see Figure 5), and AoI-3 on 02 December 2022 at 03:51 (see Figure 6).…”

“…Sentinel-1 SAR images of three Areas of Interest (AoI) were processed throughout this research [7]. The AoI-1 is located in the Northwest coasts (Pomos Port), the AoI-2 in the Southeast coasts (Cape Greco) and the AoI-3 in the Southeast coasts (Larnaca port).…”

“…The AoI-1 is located in the Northwest coasts (Pomos Port), the AoI-2 in the Southeast coasts (Cape Greco) and the AoI-3 in the Southeast coasts (Larnaca port). Sentinel-1 data from the Copernicus Open Access Hub was used through the online interface [7].…”

“…Initially, the whole Sentinel-1 acquisitions were downloaded from Copernicus Open Access Hub. These were subsequently cropped to obtain smaller areas covering the selected AoIs and speed up the processing time [7]. Likewise, in this paper, we construct a YOLOv3-based end-to-end training convolutional neural network to detect ships.…”