38 research outputs found
SAR Ship Detection for Rough Sea Conditions
In the Synthetic Aperture Radar (SAR) framework many detection algorithms and techniques have been published in the recent literature; however the detection of vessels whose dimensions are in the order of the image spatial resolution is still challenging in rough sea state scenarios. This issue is addressed in the paper presented here by comparing rationale and performance of two detectors developed by the same authors: the Generalized Likelihood Ratio Test (GLRT) and the Intensity Dual-Polarization Ratio Anomaly Detector (iDPolRAD). Both detectors are tested on a dual-polarization VV/VH Interferometric Wide Swath Sentinel-1 image acquired over the Suruga Bay on the Pacific Coast of Japan. The theory is presented here and the two detectors are compared against the Cell Average-Constant False Alarm Algorithm (CA-CFAR) showing both better performance than CFAR in terms of false alarms rejection
Ship detection in SAR images based on Maxtree representation and graph signal processing
Β© 2018 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 paper discusses an image processing architecture and tools to address the problem of ship detection in synthetic-aperture radar images. The detection strategy relies on a tree-based representation of images, here a Maxtree, and graph signal processing tools. Radiometric as well as geometric attributes are evaluated and associated with the Maxtree nodes. They form graph attribute signals which are processed with graph filters. The goal of this filtering step is to exploit the correlation existing between attribute values on neighboring tree nodes. Considering that trees are specific graphs where the connectivity toward ancestors and descendants may have a different meaning, we analyze several linear, nonlinear, and morphological filtering strategies. Beside graph filters, two new filtering notions emerge from this analysis: tree and branch filters. Finally, we discuss a ship detection architecture that involves graph signal filters and machine learning tools. This architecture demonstrates the interest of applying graph signal processing tools on the tree-based representation of images and of going beyond classical graph filters. The resulting approach significantly outperforms state-of-the-art algorithms. Finally, a MATLAB toolbox allowing users to experiment with the tools discussed in this paper on Maxtree or Mintree has been created and made public.Peer ReviewedPostprint (author's final draft
A ship detector applying Principal Component Analysis to the polarimetric Notch Filter
Ship detection using polarimetric synthetic aperture radar (PolSAR) data has attracted a lot of attention in recent years. Polarimetry can provide information regarding the scattering mechanisms of targets, which helps discriminate between ships and sea clutter. This enhancement is particularly valuable when we aim at detecting smaller vessels in rough sea states. This work exploits a ship detector called the Geometrical Perturbation-Polarimetric Notch Filter (GP-PNF), and it is aimed at improving its performance especially when less polarimetric images are available (e.g., dual-polarimetric data). The idea is to design a new polarimetric feature vector containing more features that are renowned to allow separation between ships and sea clutter. Then, a Principal Component Analysis (PCA) is further used to reduce the dimensionality of the new feature space. Experiments on four real Sentinel-1 datasets are carried out to demonstrate the validity of the proposed method and compare it against other ship detectors. Analyses of the experimental results show that the proposed algorithm can not only reduce the false alarms significantly, but also enhance the target-to-clutter ratio (TCR) so that it can more effectively detect weaker ships
The Polarimetric Detection Optimization Filter and Its Statistical Test for Ship Detection
Ship detection via synthetic aperture radar (SAR) has been demonstrated to be very useful as polarimetric information helps discriminate between targets and sea clutter. Among the available polarimetric detectors, optimal polarimetric detection (OPD) theoretically provides the best detection performance under the assumption that the fully developed speckle hypothesis stands. This study proposes a polarimetric detection optimization filter (PDOF). The target clutter ratio (TCR) over the speckle variation was maximized using a matrix transform to derive the PDOF. The objective function based on a matrix transform instead of a vector transform is optimized to obtain synthetic effects by combining a polarimetric whitening filter (PWF) and a polarimetric matched filter (PMF). Subspace form of the PDOF (SPDOF) is also proposed, which gives performance comparable to the PDOF. Assuming a Wishart distribution, the exact and approximate expressions of the closed-form probability density function (PDF) of the PDOF are derived. The probability of false alarm (PFA) was derived in a closed-form expression, which allows obtaining the PDOF threshold analytically. Moreover, the gamma model is extended to a generalized gamma distribution (GΞD) to adapt complicated resolutions and sea states. Experiments with simulated and real data validate the correctness and effectiveness of the results. The PDOF detector achieves the best performance in most virtual and real-world environments, especially in cases where the target statistics and clutter are not Wishart-distributed
PolSAR Ship Detection Based on Neighborhood Polarimetric Covariance Matrix
The detection of small ships in polarimetric synthetic aperture radar (PolSAR) images is still a topic for further investigation. Recently, patch detection techniques, such as superpixel-level detection, have stimulated wide interest because they can use the information contained in similarities among neighboring pixels. In this article, we propose a novel neighborhood polarimetric covariance matrix (NPCM) to detect the small ships in PolSAR images, leading to a significant improvement in the separability between ship targets and sea clutter. The NPCM utilizes the spatial correlation between neighborhood pixels and maps the representation for a given pixel into a high-dimensional covariance matrix by embedding spatial and polarization information. Using the NPCM formalism, we apply a standard whitening filter, similar to the polarimetric whitening filter (PWF). We show how the inclusion of neighborhood information improves the performance compared with the traditional polarimetric covariance matrix. However, this is at the expense of a higher computation cost. The theory is validated via the simulated and measured data under different sea states and using different radar platforms
Synthetic Aperture Radar (SAR) Meets Deep Learning
This reprint focuses on the application of the combination of synthetic aperture radars and depth learning technology. It aims to further promote the development of SAR image intelligent interpretation technology. A synthetic aperture radar (SAR) is an important active microwave imaging sensor, whose all-day and all-weather working capacity give it an important place in the remote sensing community. Since the United States launched the first SAR satellite, SAR has received much attention in the remote sensing community, e.g., in geological exploration, topographic mapping, disaster forecast, and traffic monitoring. It is valuable and meaningful, therefore, to study SAR-based remote sensing applications. In recent years, deep learning represented by convolution neural networks has promoted significant progress in the computer vision community, e.g., in face recognition, the driverless field and Internet of things (IoT). Deep learning can enable computational models with multiple processing layers to learn data representations with multiple-level abstractions. This can greatly improve the performance of various applications. This reprint provides a platform for researchers to handle the above significant challenges and present their innovative and cutting-edge research results when applying deep learning to SAR in various manuscript types, e.g., articles, letters, reviews and technical reports
Π‘ΠΈΠ½ΡΠ΅Π· ΠΎΠ±ΠΎΠ±ΡΠ΅Π½Π½ΠΎΠ³ΠΎ Π°Π»Π³ΠΎΡΠΈΡΠΌΠ° ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ ΠΈ ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π΄Π°Π½Π½ΡΡ ΠΏΠΎ ΠΎΡΡΠ°ΠΆΠ΅Π½Π½ΡΠΌ ΡΠΈΠ³Π½Π°Π»Π°ΠΌ ΠΎΡ ΡΠ»ΠΎΠΆΠ½ΡΡ ΡΠ΅Π»Π΅ΠΉ
Introduction. The quality of input information for trajectory processing (TP) systems can be improved by increasing the measurement accuracy of radar sensors (RS). However, in such a case, radar targets acquire the characteristics of complex targets having several marks at the output of the detector. This makes it difficult to accurately assess the kinetic parameters of targets in a TP system. In this respect, the development of a generalized algorithm for processing and generating data from the reflected signals of complex targets seems a relevant research task.Aim. To investigate reasons for the formation of complex targets and, using the theory of radar image processing, to synthesize an algorithm for processing and generating data on reflected signals from a complex target.Materials and methods. The following methodological approaches were used: the theory of digital signal processing; applied theory of radar image processing; MATLAB Simulink Toolboxes for simulating radar image processing; some prerequisites for fuzzy clustering methods.Results. Following an analysis of some characteristics of complex targets and the theory of radar image processing, an generalized algorithm was synthesized for processing and generating data of reflected signals from this class of targets. The results can be used to improve the measurement accuracy of their representative point when solving the TP problem.Conclusion. Reasons for the formation of complex targets in radar technology were analyzed. Their specific features consist in the need to accurately assess a true mark. A generalized algorithm for processing and generating these signals reflected from complex targets was proposed. The results can serve as a basis for solving the TP problem.ΠΠ²Π΅Π΄Π΅Π½ΠΈΠ΅. ΠΠΎΠ²ΡΡΠ΅Π½ΠΈΠ΅ ΠΊΠ°ΡΠ΅ΡΡΠ²Π° Π²Ρ
ΠΎΠ΄Π½ΠΎΠΉ ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠΈ Π΄Π»Ρ ΡΠΈΡΡΠ΅ΠΌΡ ΡΡΠ°Π΅ΠΊΡΠΎΡΠ½ΠΎΠΉ ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ (Π’Π) Π½Π° ΠΎΡΠ½ΠΎΠ²Π΅ ΠΏΠΎΠ²ΡΡΠ΅Π½ΠΈΡ ΡΠΎΡΠ½ΠΎΡΡΠΈ ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½ΠΈΠΉ ΡΠ°Π΄ΠΈΠΎΠ»ΠΎΠΊΠ°ΡΠΈΠΎΠ½Π½ΡΡ
(Π Π) ΡΠ΅Π½ΡΠΎΡΠΎΠ² ΡΠ²Π»ΡΠ΅ΡΡΡ ΠΎΠ΄Π½ΠΈΠΌ ΠΈΠ· ΠΎΡΠ΅Π²ΠΈΠ΄Π½ΡΡ
ΠΏΠΎΠ΄Ρ
ΠΎΠ΄ΠΎΠ². ΠΠ΄Π½Π°ΠΊΠΎ ΠΏΡΠΈ ΡΡΠΎΠΌ Π Π-ΡΠ΅Π»ΠΈ ΠΌΠΎΠ³ΡΡ ΡΡΠ°ΡΡ "ΡΠ»ΠΎΠΆΠ½ΡΠΌΠΈ ΡΠ΅Π»ΡΠΌΠΈ", ΠΈΠΌΠ΅ΡΡΠΈΠΌΠΈ Π½Π΅ΡΠΊΠΎΠ»ΡΠΊΠΎ ΠΎΡΠΌΠ΅ΡΠΎΠΊ Π½Π° Π²ΡΡ
ΠΎΠ΄Π΅ ΠΎΠ±Π½Π°ΡΡΠΆΠΈΡΠ΅Π»Ρ. ΠΡΠΎ Π·Π°ΡΡΡΠ΄Π½ΡΠ΅Ρ ΡΠΎΡΠ½ΡΡ ΠΎΡΠ΅Π½ΠΊΡ ΠΊΠΈΠ½Π΅ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ² ΡΠ΅Π»Π΅ΠΉ Π² ΡΠΈΡΡΠ΅ΠΌΠ΅ Π’Π. Π ΡΡΠ°ΡΡΠ΅ ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½Ρ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΡ ΡΠΈΠ½ΡΠ΅Π·Π° ΠΎΠ±ΠΎΠ±ΡΠ΅Π½Π½ΠΎΠ³ΠΎ Π°Π»Π³ΠΎΡΠΈΡΠΌΠ° ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ ΠΈ ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π΄Π°Π½Π½ΡΡ
ΠΈΠ· ΠΎΡΡΠ°ΠΆΠ΅Π½Π½ΡΡ
ΡΠΈΠ³Π½Π°Π»ΠΎΠ² ΡΠ»ΠΎΠΆΠ½ΡΡ
ΡΠ΅Π»Π΅ΠΉ, ΠΏΠΎΠ·Π²ΠΎΠ»ΡΡΡΠ΅Π³ΠΎ ΡΠΎΡΠ½ΠΎ ΠΎΡΠ΅Π½ΠΈΡΡ ΠΊΠΈΠ½Π΅ΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΡ Π΄Π»Ρ ΡΠ΅ΡΠ΅Π½ΠΈΡ Π·Π°Π΄Π°ΡΠΈ Π’Π.Π¦Π΅Π»Ρ ΡΠ°Π±ΠΎΡΡ. ΠΡΠ°ΡΠΊΠΎΠ΅ ΠΈΠ·ΡΡΠ΅Π½ΠΈΠ΅ ΠΏΡΠΈΡΠΈΠ½ ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ "ΡΠ»ΠΎΠΆΠ½ΡΡ
ΡΠ΅Π»Π΅ΠΉ". Π‘ΠΈΠ½ΡΠ΅Π· ΠΎΠ±ΠΎΠ±ΡΠ΅Π½Π½ΠΎΠ³ΠΎ Π°Π»Π³ΠΎΡΠΈΡΠΌΠ° ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ ΠΈ ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π΄Π°Π½Π½ΡΡ
ΠΏΠΎ ΠΎΡΡΠ°ΠΆΠ΅Π½Π½ΡΠΌ ΡΠΈΠ³Π½Π°Π»Π°ΠΌ ΠΎΡ ΡΠ»ΠΎΠΆΠ½ΡΡ
ΡΠ΅Π»Π΅ΠΉ Π½Π° ΠΎΡΠ½ΠΎΠ²Π΅ ΡΠ΅ΠΎΡΠΈΠΈ ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ Π Π-ΠΈΠ·ΠΎΠ±ΡΠ°ΠΆΠ΅Π½ΠΈΠΉ.ΠΠ°ΡΠ΅ΡΠΈΠ°Π»Ρ ΠΈ ΠΌΠ΅ΡΠΎΠ΄Ρ. Π’Π΅ΠΎΡΠΈΡ ΡΠΈΡΡΠΎΠ²ΠΎΠΉ ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ ΡΠΈΠ³Π½Π°Π»ΠΎΠ²; ΠΏΡΠΈΠΊΠ»Π°Π΄Π½Π°Ρ ΡΠ΅ΠΎΡΠΈΡ ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ Π Π-ΠΈΠ·ΠΎΠ±ΡΠ°ΠΆΠ΅Π½ΠΈΠΉ; MATLAB Simulink Toolboxes Π΄Π»Ρ ΠΌΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ Π Π-ΠΈΠ·ΠΎΠ±ΡΠ°ΠΆΠ΅Π½ΠΈΠΉ; ΠΌΠ΅ΡΠΎΠ΄Ρ Π½Π΅ΡΠ΅ΡΠΊΠΎΠΉ ΠΊΠ»Π°ΡΡΠ΅ΡΠΈΠ·Π°ΡΠΈΠΈ.Π Π΅Π·ΡΠ»ΡΡΠ°ΡΡ. ΠΠ° ΠΎΡΠ½ΠΎΠ²Π΅ Π°Π½Π°Π»ΠΈΠ·Π° Π½Π΅ΠΊΠΎΡΠΎΡΡΡ
Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊ ΡΠ»ΠΎΠΆΠ½ΡΡ
ΡΠ΅Π»Π΅ΠΉ ΠΈ ΡΠ΅ΠΎΡΠΈΠΈ ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ Π Π-ΠΈΠ·ΠΎΠ±ΡΠ°ΠΆΠ΅Π½ΠΈΠΉ ΡΠΈΠ½ΡΠ΅Π·ΠΈΡΠΎΠ²Π°Π½ ΠΎΠ±ΠΎΠ±ΡΠ΅Π½Π½ΡΠΉ Π°Π»Π³ΠΎΡΠΈΡΠΌ ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ ΠΈ ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π΄Π°Π½Π½ΡΡ
ΠΎΡΡΠ°ΠΆΠ΅Π½Π½ΡΡ
ΡΠΈΠ³Π½Π°Π»ΠΎΠ² ΠΎΡ ΡΡΠΎΠ³ΠΎ ΠΊΠ»Π°ΡΡΠ° ΡΠ΅Π»Π΅ΠΉ, ΡΠ²Π»ΡΡΡΠΈΡ
ΡΡ ΠΏΡΠ΅Π΄ΠΏΠΎΡΡΠ»ΠΊΠΎΠΉ Π΄Π»Ρ ΡΠΎΡΠ½ΠΎΠΉ ΠΎΡΠ΅Π½ΠΊΠΈ ΠΈΡ
"ΠΏΡΠ΅Π΄ΡΡΠ°Π²ΠΈΡΠ΅Π»ΡΠ½ΠΎΠΉ ΠΎΡΠΌΠ΅ΡΠΊΠΈ" ΠΏΡΠΈ ΡΠ΅ΡΠ΅Π½ΠΈΠΈ Π·Π°Π΄Π°ΡΠΈ Π’Π.ΠΠ°ΠΊΠ»ΡΡΠ΅Π½ΠΈΠ΅. Π ΡΡΠ°ΡΡΠ΅ ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½ Π°Π½Π°Π»ΠΈΠ· ΠΎΡΠΎΠ±Π΅Π½Π½ΠΎΡΡΠ΅ΠΉ ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΡΠ»ΠΎΠΆΠ½ΡΡ
ΡΠ΅Π»Π΅ΠΉ Π² Π Π-ΡΠ΅Ρ
Π½ΠΈΠΊΠ΅ ΠΈ ΠΈΡ
ΠΎΡΠΎΠ±Π΅Π½Π½ΠΎΡΡΠ΅ΠΉ ΠΏΡΠΈ ΡΠΎΡΠ½ΠΎΠΉ ΠΎΡΠ΅Π½ΠΊΠ΅ ΠΈΡΡΠΈΠ½Π½ΠΎΠΉ ΠΎΡΠΌΠ΅ΡΠΊΠΈ; ΡΠΈΠ½ΡΠ΅Π·ΠΈΡΠΎΠ²Π°Π½ ΠΎΠ±ΠΎΠ±ΡΠ΅Π½Π½ΡΠΉ Π°Π»Π³ΠΎΡΠΈΡΠΌ ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ ΠΈ ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π Π-ΡΠΈΠ³Π½Π°Π»ΠΎΠ², ΠΎΡΡΠ°ΠΆΠ΅Π½Π½ΡΡ
ΠΎΡ ΡΠ»ΠΎΠΆΠ½ΡΡ
ΡΠ΅Π»Π΅ΠΉ, ΡΠ²Π»ΡΡΡΠΈΠΉΡΡ ΠΎΡΠ½ΠΎΠ²ΠΎΠΉ ΠΏΡΠΈ ΡΠ΅ΡΠ΅Π½ΠΈΠΈ Π·Π°Π΄Π°Ρ Π’Π
SAR Image Edge Detection: Review and Benchmark Experiments
Edges are distinct geometric features crucial to higher level object detection and recognition in remote-sensing processing, which is a key for surveillance and gathering up-to-date geospatial intelligence. Synthetic aperture radar (SAR) is a powerful form of remote-sensing. However, edge detectors designed for optical images tend to have low performance on SAR images due to the presence of the strong speckle noise-causing false-positives (type I errors). Therefore, many researchers have proposed edge detectors that are tailored to deal with the SAR image characteristics specifically. Although these edge detectors might achieve effective results on their own evaluations, the comparisons tend to include a very limited number of (simulated) SAR images. As a result, the generalized performance of the proposed methods is not truly reflected, as real-world patterns are much more complex and diverse. From this emerges another problem, namely, a quantitative benchmark is missing in the field. Hence, it is not currently possible to fairly evaluate any edge detection method for SAR images. Thus, in this paper, we aim to close the aforementioned gaps by providing an extensive experimental evaluation for SAR images on edge detection. To that end, we propose the first benchmark on SAR image edge detection methods established by evaluating various freely available methods, including methods that are considered to be the state of the art
Ship Identification on Satellite Image Using Convolutional Neural Network and Random Forest
Ship identification on satellite imagery can be used for fisheries management, monitoring of smuggling activities, ship traffic services, and naval warfare. However, high-resolution satellite imagery also makes the segmentation of the ship difficult in the background, so that to handle it requires reliable features so that it can be identified adequately between large vessels, small vessels and not ships. The Convolutional Neural Network (CNN) method, which has the advantage of being able to extract features automatically and produce reliable features that facilitate ship identification. This study combines CNN ZFNet architecture with the Random Forest method. The training was conducted with the aim of knowing the accuracy of the ZFNet layers to produce the best features, which are characterized by high accuracy, combined with the Random Forest method. Testing the combination of this method is done with two parameters, namely batch size and a number of trees. The test results identify large vessels with an accuracy of 87.5% and small vessels with an accuracy of not up to 50%