语义分割(CSS)的持续学习是一个快速新兴的领域,其中分割模型的功能通过学习新类或新域而逐渐改善。持续学习中的一个核心挑战是克服灾难性遗忘的影响,这是指在模型对新类或领域进行培训后,准确性突然下降了先前学习的任务。在持续分类中,通常通过重播以前任务中的少量样本来克服这种挑战,但是在CSS中很少考虑重播。因此,我们研究了各种重播策略对语义细分的影响,并在类和域内的环境中评估它们。我们的发现表明,在课堂开发环境中,至关重要的是,对于缓冲区中不同类别的不同类别的分布至关重要,以避免对新学习的班级产生偏见。在域内营养设置中,通过从学习特征表示的分布或通过中位熵选择样品来选择缓冲液样品是最有效的。最后,我们观察到,有效的抽样方法有助于减少早期层中的表示形式的变化,这是忘记域内收入学习的主要原因。
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持续深度学习的领域是一个新兴领域,已经取得了很多进步。但是,同时仅根据图像分类的任务进行了大多数方法,这在智能车辆领域无关。直到最近才提出了班级开展语义分割的方法。但是,所有这些方法都是基于某种形式的知识蒸馏。目前,尚未对基于重播的方法进行调查,这些方法通常在连续的环境中用于对象识别。同时,尽管无监督的语义分割的域适应性获得了很多吸引力,但在持续环境中有关域内收入学习的调查并未得到充分研究。因此,我们工作的目的是评估和调整已建立的解决方案,以连续对象识别语义分割任务,并为连续语义分割的任务提供基线方法和评估协议。首先,我们介绍了类和域内的分割的评估协议,并分析了选定的方法。我们表明,语义分割变化的任务的性质在减轻与图像分类相比最有效的方法中最有效。特别是,在课堂学习中,学习知识蒸馏被证明是至关重要的工具,而在域内,学习重播方法是最有效的方法。
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语义细分(CISS)的课堂学习学习目前是一个经过深入研究的领域,旨在通过依次学习新的语义类别来更新语义分割模型。 CISS中的一个主要挑战是克服灾难性遗忘的影响,这描述了在模型接受新的一组课程培训之后,先前学习的类的准确性突然下降。尽管在减轻灾难性遗忘方面取得了最新进展,但在CISS中特别遗忘的根本原因尚未得到很好的理解。因此,在一组实验和代表性分析中,我们证明了背景类别的语义转移和对新类别的偏见是忘记CISS的主要原因。此外,我们表明两者都在网络的更深层分类层中表现出来,而模型的早期层没有影响。最后,我们证明了如何利用背景中包含的信息在知识蒸馏和无偏见的跨透镜损失的帮助下有效地减轻两种原因。
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深度神经网络在学习新任务时遭受灾难性遗忘的主要限制。在本文中,我们专注于语义细分中的课堂持续学习,其中新类别随着时间的推移,而在未保留以前的训练数据。建议的持续学习方案塑造了潜在的空间来减少遗忘,同时提高了对新型课程的识别。我们的框架是由三种新的组件驱动,我们还毫不费力地结合现有的技术。首先,匹配的原型匹配在旧类上强制执行潜在空间一致性,约束编码器在后续步骤中为先前看到的类生成类似的潜在潜在表示。其次,特征稀疏性允许在潜在空间中腾出空间以容纳新型课程。最后,根据他们的语义,在统一的同时撕裂不同类别的语义,对形成对比的学习。对Pascal VOC2012和ADE20K数据集的广泛评估展示了我们方法的有效性,显着优于最先进的方法。
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Class-Incremental Learning is a challenging problem in machine learning that aims to extend previously trained neural networks with new classes. This is especially useful if the system is able to classify new objects despite the original training data being unavailable. While the semantic segmentation problem has received less attention than classification, it poses distinct problems and challenges since previous and future target classes can be unlabeled in the images of a single increment. In this case, the background, past and future classes are correlated and there exist a background-shift. In this paper, we address the problem of how to model unlabeled classes while avoiding spurious feature clustering of future uncorrelated classes. We propose to use Evidential Deep Learning to model the evidence of the classes as a Dirichlet distribution. Our method factorizes the problem into a separate foreground class probability, calculated by the expected value of the Dirichlet distribution, and an unknown class (background) probability corresponding to the uncertainty of the estimate. In our novel formulation, the background probability is implicitly modeled, avoiding the feature space clustering that comes from forcing the model to output a high background score for pixels that are not labeled as objects. Experiments on the incremental Pascal VOC, and ADE20k benchmarks show that our method is superior to state-of-the-art, especially when repeatedly learning new classes with increasing number of increments.
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Continual Learning is a step towards lifelong intelligence where models continuously learn from recently collected data without forgetting previous knowledge. Existing continual learning approaches mostly focus on image classification in the class-incremental setup with clear task boundaries and unlimited computational budget. This work explores Online Domain-Incremental Continual Segmentation~(ODICS), a real-world problem that arises in many applications, \eg, autonomous driving. In ODICS, the model is continually presented with batches of densely labeled images from different domains; computation is limited and no information about the task boundaries is available. In autonomous driving, this may correspond to the realistic scenario of training a segmentation model over time on a sequence of cities. We analyze several existing continual learning methods and show that they do not perform well in this setting despite working well in class-incremental segmentation. We propose SimCS, a parameter-free method complementary to existing ones that leverages simulated data as a continual learning regularizer. Extensive experiments show consistent improvements over different types of continual learning methods that use regularizers and even replay.
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Despite significant advances, the performance of state-of-the-art continual learning approaches hinges on the unrealistic scenario of fully labeled data. In this paper, we tackle this challenge and propose an approach for continual semi-supervised learning -- a setting where not all the data samples are labeled. An underlying issue in this scenario is the model forgetting representations of unlabeled data and overfitting the labeled ones. We leverage the power of nearest-neighbor classifiers to non-linearly partition the feature space and learn a strong representation for the current task, as well as distill relevant information from previous tasks. We perform a thorough experimental evaluation and show that our method outperforms all the existing approaches by large margins, setting a strong state of the art on the continual semi-supervised learning paradigm. For example, on CIFAR100 we surpass several others even when using at least 30 times less supervision (0.8% vs. 25% of annotations).
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人类智慧的主食是以不断的方式获取知识的能力。在Stark对比度下,深网络忘记灾难性,而且为此原因,类增量连续学习促进方法的子字段逐步学习一系列任务,将顺序获得的知识混合成综合预测。这项工作旨在评估和克服我们以前提案黑暗体验重播(Der)的陷阱,这是一种简单有效的方法,将排练和知识蒸馏结合在一起。灵感来自于我们的思想不断重写过去的回忆和对未来的期望,我们赋予了我的能力,即我的能力来修改其重播记忆,以欢迎有关过去数据II的新信息II)为学习尚未公开的课程铺平了道路。我们表明,这些策略的应用导致了显着的改进;实际上,得到的方法 - 被称为扩展-DAR(X-DER) - 优于标准基准(如CiFar-100和MiniimAgeNet)的技术状态,并且这里引入了一个新颖的。为了更好地了解,我们进一步提供了广泛的消融研究,以证实并扩展了我们以前研究的结果(例如,在持续学习设置中知识蒸馏和漂流最小值的价值)。
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凭借持续学习的能力,人类可以在整个生命周期中不断获得知识。但是,一般而言,计算系统不能顺序学习任务。对深神经网络(DNN)的长期挑战称为灾难性遗忘。已经提出了多种解决方案来克服这一限制。本文对内存重播方法进行了深入的评估,从而探讨了选择重播数据时各种采样策略的效率,性能和可扩展性。所有实验均在各个域下的多个数据集上进行。最后,提供了为各种数据分布选择重播方法的实用解决方案。
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在线持续学习是一个充满挑战的学习方案,模型必须从非平稳的数据流中学习,其中每个样本只能看到一次。主要的挑战是在避免灾难性遗忘的同时逐步学习,即在从新数据中学习时忘记先前获得的知识的问题。在这种情况下,一种流行的解决方案是使用较小的内存来保留旧数据并随着时间的推移进行排练。不幸的是,由于内存尺寸有限,随着时间的推移,内存的质量会恶化。在本文中,我们提出了OLCGM,这是一种基于新型重放的持续学习策略,该策略使用知识冷凝技术连续压缩记忆并更好地利用其有限的尺寸。样品冷凝步骤压缩了旧样品,而不是像其他重播策略那样将其删除。结果,实验表明,每当与数据的复杂性相比,每当记忆预算受到限制,OLCGM都会提高与最先进的重播策略相比的最终准确性。
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对于图像的语义分割,如果该任务限于一组封闭的类,则最先进的深神经网络(DNN)实现高分性精度。然而,截至目前,DNN具有有限的开放世界能够在开放世界中运行,在那里他们任务是识别属于未知对象的像素,最终逐步学习新颖的类。人类有能力说:我不知道那是什么,但我已经看到了这样的东西。因此,希望以无监督的方式执行这种增量学习任务。我们介绍一种基于视觉相似性群集未知对象的方法。这些集群用于定义新课程,并作为无监督增量学习的培训数据。更确切地说,通过分割质量估计来评估预测语义分割的连接组件。具有低估计预测质量的连接组件是随后聚类的候选者。另外,组件明智的质量评估允许获得可能包含未知对象的图像区域的预测分段掩模。这种掩模的各个像素是伪标记的,然后用于重新训练DNN,即,在不使用由人类产生的地面真理。在我们的实验中,我们证明,在没有访问地面真理甚至几个数据中,DNN的类空间可以由新颖的类扩展,实现了相当大的分割精度。
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A continual learning agent learns online with a non-stationary and never-ending stream of data. The key to such learning process is to overcome the catastrophic forgetting of previously seen data, which is a well known problem of neural networks. To prevent forgetting, a replay buffer is usually employed to store the previous data for the purpose of rehearsal. Previous works often depend on task boundary and i.i.d. assumptions to properly select samples for the replay buffer. In this work, we formulate sample selection as a constraint reduction problem based on the constrained optimization view of continual learning. The goal is to select a fixed subset of constraints that best approximate the feasible region defined by the original constraints. We show that it is equivalent to maximizing the diversity of samples in the replay buffer with parameters gradient as the feature. We further develop a greedy alternative that is cheap and efficient. The advantage of the proposed method is demonstrated by comparing to other alternatives under the continual learning setting. Further comparisons are made against state of the art methods that rely on task boundaries which show comparable or even better results for our method.
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We motivate Energy-Based Models (EBMs) as a promising model class for continual learning problems. Instead of tackling continual learning via the use of external memory, growing models, or regularization, EBMs change the underlying training objective to cause less interference with previously learned information. Our proposed version of EBMs for continual learning is simple, efficient, and outperforms baseline methods by a large margin on several benchmarks. Moreover, our proposed contrastive divergence-based training objective can be combined with other continual learning methods, resulting in substantial boosts in their performance. We further show that EBMs are adaptable to a more general continual learning setting where the data distribution changes without the notion of explicitly delineated tasks. These observations point towards EBMs as a useful building block for future continual learning methods.
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Continually learning to segment more and more types of image regions is a desired capability for many intelligent systems. However, such continual semantic segmentation suffers from the same catastrophic forgetting issue as in continual classification learning. While multiple knowledge distillation strategies originally for continual classification have been well adapted to continual semantic segmentation, they only consider transferring old knowledge based on the outputs from one or more layers of deep fully convolutional networks. Different from existing solutions, this study proposes to transfer a new type of information relevant to knowledge, i.e. the relationships between elements (Eg. pixels or small local regions) within each image which can capture both within-class and between-class knowledge. The relationship information can be effectively obtained from the self-attention maps in a Transformer-style segmentation model. Considering that pixels belonging to the same class in each image often share similar visual properties, a class-specific region pooling is applied to provide more efficient relationship information for knowledge transfer. Extensive evaluations on multiple public benchmarks support that the proposed self-attention transfer method can further effectively alleviate the catastrophic forgetting issue, and its flexible combination with one or more widely adopted strategies significantly outperforms state-of-the-art solutions.
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Deep learning models can achieve high accuracy when trained on large amounts of labeled data. However, real-world scenarios often involve several challenges: Training data may become available in installments, may originate from multiple different domains, and may not contain labels for training. Certain settings, for instance medical applications, often involve further restrictions that prohibit retention of previously seen data due to privacy regulations. In this work, to address such challenges, we study unsupervised segmentation in continual learning scenarios that involve domain shift. To that end, we introduce GarDA (Generative Appearance Replay for continual Domain Adaptation), a generative-replay based approach that can adapt a segmentation model sequentially to new domains with unlabeled data. In contrast to single-step unsupervised domain adaptation (UDA), continual adaptation to a sequence of domains enables leveraging and consolidation of information from multiple domains. Unlike previous approaches in incremental UDA, our method does not require access to previously seen data, making it applicable in many practical scenarios. We evaluate GarDA on two datasets with different organs and modalities, where it substantially outperforms existing techniques.
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Artificial neural networks thrive in solving the classification problem for a particular rigid task, acquiring knowledge through generalized learning behaviour from a distinct training phase. The resulting network resembles a static entity of knowledge, with endeavours to extend this knowledge without targeting the original task resulting in a catastrophic forgetting. Continual learning shifts this paradigm towards networks that can continually accumulate knowledge over different tasks without the need to retrain from scratch. We focus on task incremental classification, where tasks arrive sequentially and are delineated by clear boundaries. Our main contributions concern (1) a taxonomy and extensive overview of the state-of-the-art; (2) a novel framework to continually determine the stability-plasticity trade-off of the continual learner; (3) a comprehensive experimental comparison of 11 state-of-the-art continual learning methods and 4 baselines. We empirically scrutinize method strengths and weaknesses on three benchmarks, considering Tiny Imagenet and large-scale unbalanced iNaturalist and a sequence of recognition datasets. We study the influence of model capacity, weight decay and dropout regularization, and the order in which the tasks are presented, and qualitatively compare methods in terms of required memory, computation time and storage.
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恶意软件(恶意软件)分类为持续学习(CL)制度提供了独特的挑战,这是由于每天收到的新样本的数量以及恶意软件的发展以利用新漏洞。在典型的一天中,防病毒供应商将获得数十万个独特的软件,包括恶意和良性,并且在恶意软件分类器的一生中,有超过十亿个样品很容易积累。鉴于问题的规模,使用持续学习技术的顺序培训可以在减少培训和存储开销方面提供可观的好处。但是,迄今为止,还没有对CL应用于恶意软件分类任务的探索。在本文中,我们研究了11种应用于三个恶意软件任务的CL技术,涵盖了常见的增量学习方案,包括任务,类和域增量学习(IL)。具体而言,使用两个现实的大规模恶意软件数据集,我们评估了CL方法在二进制恶意软件分类(domain-il)和多类恶意软件家庭分类(Task-IL和类IL)任务上的性能。令我们惊讶的是,在几乎所有情况下,持续的学习方法显着不足以使训练数据的幼稚关节重播 - 在某些情况下,将精度降低了70个百分点以上。与关节重播相比,有选择性重播20%的存储数据的一种简单方法可以实现更好的性能,占训练时间的50%。最后,我们讨论了CL技术表现出乎意料差的潜在原因,希望它激发进一步研究在恶意软件分类域中更有效的技术。
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持续学习(CL)旨在开发单一模型适应越来越多的任务的技术,从而潜在地利用跨任务的学习以资源有效的方式。 CL系统的主要挑战是灾难性的遗忘,在学习新任务时忘记了早期的任务。为了解决此问题,基于重播的CL方法在遇到遇到任务中选择的小缓冲区中维护和重复培训。我们提出梯度Coreset重放(GCR),一种新颖的重播缓冲区选择和使用仔细设计的优化标准的更新策略。具体而言,我们选择并维护一个“Coreset”,其与迄今为止关于当前模型参数的所有数据的梯度紧密近似,并讨论其有效应用于持续学习设置所需的关键策略。在学习的离线持续学习环境中,我们在最先进的最先进的最先进的持续学习环境中表现出显着的收益(2%-4%)。我们的调查结果还有效地转移到在线/流媒体CL设置,从而显示现有方法的5%。最后,我们展示了持续学习的监督对比损失的价值,当与我们的子集选择策略相结合时,累计增益高达5%。
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持续学习旨在快速,不断地从一系列任务中学习当前的任务。与其他类型的方法相比,基于经验重播的方法表现出了极大的优势来克服灾难性的遗忘。该方法的一个常见局限性是上一个任务和当前任务之间的数据不平衡,这将进一步加剧遗忘。此外,如何在这种情况下有效解决稳定性困境也是一个紧迫的问题。在本文中,我们通过提出一个通过多尺度知识蒸馏和数据扩展(MMKDDA)提出一个名为Meta学习更新的新框架来克服这些挑战。具体而言,我们应用多尺度知识蒸馏来掌握不同特征级别的远程和短期空间关系的演变,以减轻数据不平衡问题。此外,我们的方法在在线持续训练程序中混合了来自情节记忆和当前任务的样品,从而减轻了由于概率分布的变化而减轻了侧面影响。此外,我们通过元学习更新来优化我们的模型,该更新诉诸于前面所看到的任务数量,这有助于保持稳定性和可塑性之间的更好平衡。最后,我们对四个基准数据集的实验评估显示了提出的MMKDDA框架对其他流行基线的有效性,并且还进行了消融研究,以进一步分析每个组件在我们的框架中的作用。
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最近的自我监督学习方法能够学习高质量的图像表示,并通过监督方法关闭差距。但是,这些方法无法逐步获取新的知识 - 事实上,它们实际上主要仅用为具有IID数据的预训练阶段。在这项工作中,我们在没有额外的记忆或重放的情况下调查持续学习制度的自我监督方法。为防止忘记以前的知识,我们提出了功能正规化的使用。我们将表明,朴素的功能正则化,也称为特征蒸馏,导致可塑性的低可塑性,因此严重限制了连续的学习性能。为了解决这个问题,我们提出了预测的功能正则化,其中一个单独的投影网络确保新学习的特征空间保留了先前的特征空间的信息,同时允许学习新功能。这使我们可以防止在保持学习者的可塑性时忘记。针对应用于自我监督的其他增量学习方法的评估表明我们的方法在不同场景和多个数据集中获得竞争性能。
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