Deep learning (DL)-based tomographic SAR imaging algorithms are gradually being studied. Typically, they use an unfolding network to mimic the iterative calculation of the classical compressive sensing (CS)-based methods and process each range-azimuth unit individually. However, only one-dimensional features are effectively utilized in this way. The correlation between adjacent resolution units is ignored directly. To address that, we propose a new model-data-driven network to achieve tomoSAR imaging based on multi-dimensional features. Guided by the deep unfolding methodology, a two-dimensional deep unfolding imaging network is constructed. On the basis of it, we add two 2D processing modules, both convolutional encoder-decoder structures, to enhance multi-dimensional features of the imaging scene effectively. Meanwhile, to train the proposed multifeature-based imaging network, we construct a tomoSAR simulation dataset consisting entirely of simulation data of buildings. Experiments verify the effectiveness of the model. Compared with the conventional CS-based FISTA method and DL-based gamma-Net method, the result of our proposed method has better performance on completeness while having decent imaging accuracy.
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Benefiting from a relatively larger aperture's angle, and in combination with a wide transmitting bandwidth, near-field synthetic aperture radar (SAR) provides a high-resolution image of a target's scattering distribution-hot spots. Meanwhile, imaging result suffers inevitable degradation from sidelobes, clutters, and noises, hindering the information retrieval of the target. To restore the image, current methods make simplified assumptions; for example, the point spread function (PSF) is spatially consistent, the target consists of sparse point scatters, etc. Thus, they achieve limited restoration performance in terms of the target's shape, especially for complex targets. To address these issues, a preliminary study is conducted on restoration with the recent promising deep learning inverse technique in this work. We reformulate the degradation model into a spatially variable complex-convolution model, where the near-field SAR's system response is considered. Adhering to it, a model-based deep learning network is designed to restore the image. A simulated degraded image dataset from multiple complex target models is constructed to validate the network. All the images are formulated using the electromagnetic simulation tool. Experiments on the dataset reveal their effectiveness. Compared with current methods, superior performance is achieved regarding the target's shape and energy estimation.
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This work focuses on 3D Radar imaging inverse problems. Current methods obtain undifferentiated results that suffer task-depended information retrieval loss and thus don't meet the task's specific demands well. For example, biased scattering energy may be acceptable for screen imaging but not for scattering diagnosis. To address this issue, we propose a new task-oriented imaging framework. The imaging principle is task-oriented through an analysis phase to obtain task's demands. The imaging model is multi-cognition regularized to embed and fulfill demands. The imaging method is designed to be general-ized, where couplings between cognitions are decoupled and solved individually with approximation and variable-splitting techniques. Tasks include scattering diagnosis, person screen imaging, and parcel screening imaging are given as examples. Experiments on data from two systems indicate that the pro-posed framework outperforms the current ones in task-depended information retrieval.
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The explosive growth of dynamic and heterogeneous data traffic brings great challenges for 5G and beyond mobile networks. To enhance the network capacity and reliability, we propose a learning-based dynamic time-frequency division duplexing (D-TFDD) scheme that adaptively allocates the uplink and downlink time-frequency resources of base stations (BSs) to meet the asymmetric and heterogeneous traffic demands while alleviating the inter-cell interference. We formulate the problem as a decentralized partially observable Markov decision process (Dec-POMDP) that maximizes the long-term expected sum rate under the users' packet dropping ratio constraints. In order to jointly optimize the global resources in a decentralized manner, we propose a federated reinforcement learning (RL) algorithm named federated Wolpertinger deep deterministic policy gradient (FWDDPG) algorithm. The BSs decide their local time-frequency configurations through RL algorithms and achieve global training via exchanging local RL models with their neighbors under a decentralized federated learning framework. Specifically, to deal with the large-scale discrete action space of each BS, we adopt a DDPG-based algorithm to generate actions in a continuous space, and then utilize Wolpertinger policy to reduce the mapping errors from continuous action space back to discrete action space. Simulation results demonstrate the superiority of our proposed algorithm to benchmark algorithms with respect to system sum rate.
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公平性是一个标准,重点是评估不同人口组的算法性能,它引起了自然语言处理,推荐系统和面部识别的关注。由于医学图像样本中有很多人口统计学属性,因此了解公平的概念,熟悉不公平的缓解技术,评估算法的公平程度并认识到医疗图像分析(媒体)中的公平问题中的挑战很重要。在本文中,我们首先给出了公平性的全面和精确的定义,然后通过在媒体中引入当前使用的技术中使用的技术。之后,我们列出了包含人口统计属性的公共医疗图像数据集,以促进公平研究并总结有关媒体公平性的当前算法。为了帮助更好地理解公平性,并引起人们对媒体中与公平性有关的问题的关注,进行了实验,比较公平性和数据失衡之间的差异,验证各种媒体任务中不公平的存在,尤其是在分类,细分和检测以及评估不公平缓解算法的有效性。最后,我们以媒体公平性的机会和挑战得出结论。
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随着卷积神经网络(CNN)的蓬勃发展,诸如VGG-16和Resnet-50之类的CNN广泛用作SAR船检测中的骨架。但是,基于CNN的骨干很难对远程依赖性进行建模,并且导致缺乏浅层特征图中缺乏足够的高质量语义信息,从而导致在复杂的背景和小型船只中的检测性能不佳。为了解决这些问题,我们提出了一种基于SWIN Transformer的SAR船检测方法,并提出了功能增强功能功能金字塔网络(FEFPN)。SWIN Transformer用作建模远程依赖性并生成层次特征图的骨架。提出了FEFPN,以进一步提高特征地图的质量,通过逐渐增强各级特征地图的语义信息,尤其是浅层中的特征地图。在SAR船检测数据集(SSDD)上进行的实验揭示了我们提出的方法的优势。
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在过去十年中,深度学习的出现极大地帮助进步了图像。尽管实现了有希望的性能,但基于深度学习的载体算法仍然因结构和上下文特征的融合而造成的失真而挣扎,这些特征通常是从卷积编码器的深层和浅层层中获得的。在这一观察过程中,我们提出了一个新型的渐进式介绍网络,该网络维持了处理的图像的结构和上下文完整性。更具体地说,受高斯和拉普拉斯金字塔的启发,提出的网络的核心是一个名为GLE的特征提取模块。堆叠GLE模块使网络能够从不同的图像频率组件中提取图像特征。这种能力对于维持结构和上下文完整性很重要,对于高频组件对应于结构信息,而低频组件对应于上下文信息。提出的网络利用GLE功能以迭代方式逐渐以损坏的图像填充缺失区域。我们的基准测试实验表明,所提出的方法在许多最先进的介绍算法上取得了明显的改善。
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人脸图像通常以广泛的视觉量表出现。现有的面部表示通过组装有限系列的预定尺度的多尺度方案来追求处理量表变化的带宽。这种多弹药方案带来了推理负担,而预定义的量表不可避免地从真实数据中差异。取而代之的是,从数据中学习比例参数,并将其用于单发功能推理是一个不错的解决方案。为此,我们通过诉诸规模空间理论并实现两倍的设施来改革Conv层:1)Conv层从真实数据分布中学习一组尺度,每个数据分布都由Conv内核来实现; 2)该图层自动在适当的通道和位置上突出显示与输入模式量表及其存在相对应的位置。然后,我们通过堆叠改革层的层来实现分层尺度的关注,建立一种名为“比例尺注意Cons Neurnet网络”(\ textbf {scan-cnn})的新颖风格。我们将扫描CNN应用于面部识别任务,并推动SOTA性能的前沿。当面部图像模糊时,准确性增长更为明显。同时,作为单发方案,该推断比多弹性融合更有效。与普通CNN相比,制造了一组工具,以确保对扫描CNN进行快速训练和推理成本的零增加。
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否决单图是一项普遍但又具有挑战性的任务。复杂的降雪降解和各种降解量表需要强大的代表能力。为了使否定的网络看到各种降雪并建模本地细节和全球信息的上下文相互作用,我们提出了一种称为Snowformer的功能强大的建筑。首先,它在编码器中执行比例感知功能聚合,以捕获各种降解的丰富积雪信息。其次,为了解决大规模降级,它使用了解码器中的新颖上下文交互变压器块,该互动器块在全球上下文交互中从前范围内的局部细节和全局信息进行了上下文交互。并引入本地上下文互动可改善场景细节的恢复。第三,我们设计了一个异质的特征投影头,该功能投影头逐渐融合了编码器和解码器的特征,并将精制功能投影到干净的图像中。广泛的实验表明,所提出的雪诺形雪孔比其他SOTA方法取得了重大改进。与SOTA单图像HDCW-NET相比,它在CSD测试集上将PSNR度量提高了9.2dB。此外,与一般图像恢复体系结构NAFNET相比,PSNR的增加5.13db,这验证了我们的雪诺形雪地降雪任务的强大表示能力。该代码在\ url {https://github.com/ephemeral182/snowformer}中发布。
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场景图生成(SGG)任务旨在在给定图像中检测所有对象及其成对的视觉关系。尽管SGG在过去几年中取得了显着的进展,但几乎所有现有的SGG模型都遵循相同的训练范式:他们将SGG中的对象和谓词分类视为单标签分类问题,而地面真实性是一个hot目标。标签。但是,这种普遍的训练范式忽略了当前SGG数据集的两个特征:1)对于正样本,某些特定的主题对象实例可能具有多个合理的谓词。 2)对于负样本,有许多缺失的注释。不管这两个特征如何,SGG模型都很容易被混淆并做出错误的预测。为此,我们为无偏SGG提出了一种新颖的模型不合命相的标签语义知识蒸馏(LS-KD)。具体而言,LS-KD通过将预测的标签语义分布(LSD)与其原始的单热目标标签融合来动态生成每个主题对象实例的软标签。 LSD反映了此实例和多个谓词类别之间的相关性。同时,我们提出了两种不同的策略来预测LSD:迭代自我KD和同步自我KD。大量的消融和对三项SGG任务的结果证明了我们所提出的LS-KD的优势和普遍性,这些LS-KD可以始终如一地实现不同谓词类别之间的不错的权衡绩效。
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