A Practical Approach for SAR Image Despeckling Using Deep Learning

We propose a new method for SAR image despeckling, which performs nonlocal filtering with a deep learning engine. Nonlocal filtering has proven very effective for SAR despeckling. The key idea is to exploit image self-similarities to estimate the hidden signal. In its simplest form, pixel-wise nonlocal means, the target pixel is estimated through a weighted average of neighbors, with weights chosen on the basis of a patch-wise measure of similarity. Here, we keep the very same structure of plain nonlocal means, to ensure interpretability of results, but use a convolutional neural network to assign weights to estimators. Suitable nonlocal layers are used in the network to take into account information in a large analysis window. Experiments on both simulated and real-world SAR images show that the proposed method exhibits state-of-the-art performance. In addition, the comparison of weights generated by conventional and deep learning-based nonlocal means provides new insight into the potential and limits of nonlocal information for SAR despeckling.

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An Advanced SAR Image Despeckling Method by Bernoulli-Sampling-Based Self-Supervised Deep Learning

Remote Sensing ◽

10.3390/rs13183636 ◽

2021 ◽

Vol 13 (18) ◽

pp. 3636

Author(s):

Ye Yuan ◽

Yanxia Wu ◽

Yan Fu ◽

Yulei Wu ◽

Lidan Zhang ◽

...

Keyword(s):

Big Data ◽

Deep Learning ◽

Noise Suppression ◽

Speckle Noise ◽

Training Data ◽

Superior Performance ◽

Sar Image ◽

Sar Images ◽

Image Despeckling ◽

Image Pairs

As one of the main sources of remote sensing big data, synthetic aperture radar (SAR) can provide all-day and all-weather Earth image acquisition. However, speckle noise in SAR images brings a notable limitation for its big data applications, including image analysis and interpretation. Deep learning has been demonstrated as an advanced method and technology for SAR image despeckling. Most existing deep-learning-based methods adopt supervised learning and use synthetic speckled images to train the despeckling networks. This is because they need clean images as the references, and it is hard to obtain purely clean SAR images in real-world conditions. However, significant differences between synthetic speckled and real SAR images cause the domain gap problem. In other words, they cannot show superior performance for despeckling real SAR images as they do for synthetic speckled images. Inspired by recent studies on self-supervised denoising, we propose an advanced SAR image despeckling method by virtue of Bernoulli-sampling-based self-supervised deep learning, called SSD-SAR-BS. By only using real speckled SAR images, Bernoulli-sampled speckled image pairs (input–target) were obtained as the training data. Then, a multiscale despeckling network was trained on these image pairs. In addition, a dropout-based ensemble was introduced to boost the network performance. Extensive experimental results demonstrated that our proposed method outperforms the state-of-the-art for speckle noise suppression on both synthetic speckled and real SAR datasets (i.e., Sentinel-1 and TerraSAR-X).

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SAR Image Despeckling by Noisy Reference-Based Deep Learning Method

IEEE Transactions on Geoscience and Remote Sensing ◽

10.1109/tgrs.2020.2990978 ◽

2020 ◽

Vol 58 (12) ◽

pp. 8807-8818

Author(s):

Xiaoshuang Ma ◽

Chen Wang ◽

Zhixiang Yin ◽

Penghai Wu

Keyword(s):

Deep Learning ◽

Sar Image ◽

Learning Method ◽

Image Despeckling

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SAR Image Ship Detection Based On Deep Learning

2020 International Conference on Computer Engineering and Intelligent Control (ICCEIC) ◽

10.1109/icceic51584.2020.00019 ◽

2020 ◽

Author(s):

Jiang Kun ◽

Cao Yan

Keyword(s):

Deep Learning ◽

Sar Image ◽

Ship Detection

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High-Speed Lightweight Ship Detection Algorithm Based on YOLO-V4 for Three-Channels RGB SAR Image

Remote Sensing ◽

10.3390/rs13101909 ◽

2021 ◽

Vol 13 (10) ◽

pp. 1909

Author(s):

Jiahuan Jiang ◽

Xiongjun Fu ◽

Rui Qin ◽

Xiaoyan Wang ◽

Zhifeng Ma

Keyword(s):

Deep Learning ◽

Gpu Computing ◽

Hot Spot ◽

Detection Algorithm ◽

Detection Methods ◽

Detection Accuracy ◽

Processing Unit ◽

Sar Image ◽

Marine Monitoring ◽

Ship Detection

Synthetic Aperture Radar (SAR) has become one of the important technical means of marine monitoring in the field of remote sensing due to its all-day, all-weather advantage. National territorial waters to achieve ship monitoring is conducive to national maritime law enforcement, implementation of maritime traffic control, and maintenance of national maritime security, so ship detection has been a hot spot and focus of research. After the development from traditional detection methods to deep learning combined methods, most of the research always based on the evolving Graphics Processing Unit (GPU) computing power to propose more complex and computationally intensive strategies, while in the process of transplanting optical image detection ignored the low signal-to-noise ratio, low resolution, single-channel and other characteristics brought by the SAR image imaging principle. Constantly pursuing detection accuracy while ignoring the detection speed and the ultimate application of the algorithm, almost all algorithms rely on powerful clustered desktop GPUs, which cannot be implemented on the frontline of marine monitoring to cope with the changing realities. To address these issues, this paper proposes a multi-channel fusion SAR image processing method that makes full use of image information and the network’s ability to extract features; it is also based on the latest You Only Look Once version 4 (YOLO-V4) deep learning framework for modeling architecture and training models. The YOLO-V4-light network was tailored for real-time and implementation, significantly reducing the model size, detection time, number of computational parameters, and memory consumption, and refining the network for three-channel images to compensate for the loss of accuracy due to light-weighting. The test experiments were completed entirely on a portable computer and achieved an Average Precision (AP) of 90.37% on the SAR Ship Detection Dataset (SSDD), simplifying the model while ensuring a lead over most existing methods. The YOLO-V4-lightship detection algorithm proposed in this paper has great practical application in maritime safety monitoring and emergency rescue.

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