360 research outputs found
Ship Detection and Segmentation using Image Correlation
There have been intensive research interests in ship detection and
segmentation due to high demands on a wide range of civil applications in the
last two decades. However, existing approaches, which are mainly based on
statistical properties of images, fail to detect smaller ships and boats.
Specifically, known techniques are not robust enough in view of inevitable
small geometric and photometric changes in images consisting of ships. In this
paper a novel approach for ship detection is proposed based on correlation of
maritime images. The idea comes from the observation that a fine pattern of the
sea surface changes considerably from time to time whereas the ship appearance
basically keeps unchanged. We want to examine whether the images have a common
unaltered part, a ship in this case. To this end, we developed a method -
Focused Correlation (FC) to achieve robustness to geometric distortions of the
image content. Various experiments have been conducted to evaluate the
effectiveness of the proposed approach.Comment: 8 pages, to be published in proc. of conference IEEE SMC 201
Ship Detection Feature Analysis in Optical Satellite Imagery through Machine Learning Applications
Ship detection remains an important challenge within the government and the commercial industry. Current research has focused on deep learning and has found high success with large labeled datasets. However, deep learning becomes insufficient for limited datasets as well as when explainability is required. There exist scenarios in which explainability and human-in-the-loop processing are needed, such as in naval applications. In these scenarios, handcrafted features and traditional classification algorithms can be useful. This research aims at analyzing multiple textures and statistical features on a small optical satellite imagery dataset. The feature analysis consists of Haar-like features, Haralick features, Hu moments, Histogram of Oriented Gradients, grayscale intensity histograms, and Local Binary Patterns. Feature performance is measured using 8 different classification algorithms, including K-Nearest Neighbors, Logistic Regression, Gradient Boosting, Extreme Gradient Boosting, Support Vector Machine, Random Decision Forest, Extremely Randomized Trees, and Bagging. The features are analyzed individually and in different combinations. Individual feature analysis results found Haralick features achieved a precision of 92.2% and were computationally efficient. The best combination of features was Haralick features paired with Histogram of Oriented Gradients and grayscale intensity histograms. This combination achieved a precision score of 96.18% and an F1 score of 94.23%
Space-based Global Maritime Surveillance. Part I: Satellite Technologies
Maritime surveillance (MS) is crucial for search and rescue operations,
fishery monitoring, pollution control, law enforcement, migration monitoring,
and national security policies. Since the early days of seafaring, MS has been
a critical task for providing security in human coexistence. Several
generations of sensors providing detailed maritime information have become
available for large offshore areas in real time: maritime radar sensors in the
1950s and the automatic identification system (AIS) in the 1990s among them.
However, ground-based maritime radars and AIS data do not always provide a
comprehensive and seamless coverage of the entire maritime space. Therefore,
the exploitation of space-based sensor technologies installed on satellites
orbiting around the Earth, such as satellite AIS data, synthetic aperture
radar, optical sensors, and global navigation satellite systems reflectometry,
becomes crucial for MS and to complement the existing terrestrial technologies.
In the first part of this work, we provide an overview of the main available
space-based sensors technologies and present the advantages and limitations of
each technology in the scope of MS. The second part, related to artificial
intelligence, signal processing and data fusion techniques, is provided in a
companion paper, titled: "Space-based Global Maritime Surveillance. Part II:
Artificial Intelligence and Data Fusion Techniques" [1].Comment: This paper has been submitted to IEEE Aerospace and Electronic
Systems Magazin
Automatic Ship Detection of Remote Sensing Images from Google Earth in Complex Scenes Based on Multi-Scale Rotation Dense Feature Pyramid Networks
Ship detection has been playing a significant role in the field of remote
sensing for a long time but it is still full of challenges. The main
limitations of traditional ship detection methods usually lie in the complexity
of application scenarios, the difficulty of intensive object detection and the
redundancy of detection region. In order to solve such problems above, we
propose a framework called Rotation Dense Feature Pyramid Networks (R-DFPN)
which can effectively detect ship in different scenes including ocean and port.
Specifically, we put forward the Dense Feature Pyramid Network (DFPN), which is
aimed at solving the problem resulted from the narrow width of the ship.
Compared with previous multi-scale detectors such as Feature Pyramid Network
(FPN), DFPN builds the high-level semantic feature-maps for all scales by means
of dense connections, through which enhances the feature propagation and
encourages the feature reuse. Additionally, in the case of ship rotation and
dense arrangement, we design a rotation anchor strategy to predict the minimum
circumscribed rectangle of the object so as to reduce the redundant detection
region and improve the recall. Furthermore, we also propose multi-scale ROI
Align for the purpose of maintaining the completeness of semantic and spatial
information. Experiments based on remote sensing images from Google Earth for
ship detection show that our detection method based on R-DFPN representation
has a state-of-the-art performance.Comment: 14 pages, 11 figure
Sea target detection using spaceborne GNSS-R delay-doppler maps: theory and experimental proof of concept using TDS-1 data
© 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This study addresses a novel application of global navigation satellite system-reflectometry (GNSS-R) delay-Doppler maps (DDMs), namely sea target detection. In contrast with other competing remote sensing technologies, such as synthetic aperture radar and optical systems, typically exploited in the field of sea target detection, GNSS-R systems could be employed as satellite constellations, so as to fulfill the temporal requirements for near real-time ships and sea ice sheets monitoring. In this study, the revisit time offered by GNSS-R systems is quantitatively evaluated by means of a simulation analysis, in which three different realistic GNSS-R missions are simulated and analyzed. Then, a sea target detection algorithm from spaceborne GNSS-R DDMs is described and assessed. The algorithm is based on a sea clutter compensation step and uses an adaptive threshold to take into account spatial variations in the sea background and/or noise statistics. Finally, the sea target detector algorithm is tested and validated for the first time ever using experimental GNSS-R data from the U.K. TechDemoSat-1 dataset. Performance is assessed by providing the receiver operating characteristic curves, and some preliminary experimental results are presented.Peer ReviewedPostprint (published version
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