近年来,压缩图像超分辨率已引起了极大的关注,其中图像被压缩伪像和低分辨率伪影降解。由于复杂的杂化扭曲变形,因此很难通过简单的超分辨率和压缩伪像消除掉的简单合作来恢复扭曲的图像。在本文中,我们向前迈出了一步,提出了层次的SWIN变压器(HST)网络,以恢复低分辨率压缩图像,该图像共同捕获分层特征表示并分别用SWIN Transformer增强每个尺度表示。此外,我们发现具有超分辨率(SR)任务的预处理对于压缩图像超分辨率至关重要。为了探索不同的SR预审查的影响,我们将常用的SR任务(例如,比科比奇和不同的实际超分辨率仿真)作为我们的预处理任务,并揭示了SR在压缩的图像超分辨率中起不可替代的作用。随着HST和预训练的合作,我们的HST在AIM 2022挑战中获得了低质量压缩图像超分辨率轨道的第五名,PSNR为23.51db。广泛的实验和消融研究已经验证了我们提出的方法的有效性。
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使用深网的Visual Place识别(VPR)已达到最先进的性能。但是,他们中的大多数都需要采用地面真相传感器姿势的培训,以获取每个观察的空间邻里的正面和负面样本,以进行监督学习。当不可用的信息不可用时,尽管我们发现其性能次优训练,但可以利用从顺序收集的数据流中的时间社区进行自我监督训练。受嘈杂的标签学习的启发,我们提出了一个名为\ textit {tf-vpr}的新颖的自我监督框架,该框架使用时间社区和可学习的特征邻域来发现未知的空间社区。我们的方法遵循一个迭代训练范式,该范式在以下方面交替:(1)与数据增强的表示学习,(2)正设置扩展以包括当前的特征空间邻居,以及(3)通过几何验证进行正面集合。我们在模拟数据集和真实数据集上进行了全面的实验,将RGB图像或点云作为输入进行。结果表明,我们的方法在召回率,稳健性和标题多样性方面优于我们的基准,这是我们为VPR提出的新型指标。可以在https://ai4ce.github.io/tf-vpr/上找到我们的代码和数据集。
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机器的图像编码(ICM)旨在压缩图像进行AI任务分析,而不是满足人类的看法。学习一种既是一般(用于AI任务)的特征,也是紧凑的(用于压缩)的功能,这对于其成功而言至关重要。在本文中,我们试图通过学习通用功能,同时考虑压缩来开发ICM框架。我们将诸如无所不能功能和相应框架的功能命名为Omni-ICM。考虑到自我监督学习(SSL)提高了特征的概括,我们将其与压缩任务集成到OMNI-ICM框架中,以学习无所不能的功能。但是,在SSL中协调语义建模并在压缩中删除冗余是不平凡的,因此我们通过合作实例区分和熵最小化以自适应掉落的信息来设计新颖的信息过滤(如果)模块,以较弱相关的信息执行AI任务(例如,某些纹理冗余)。与以前的特定解决方案不同,Omni-ICM可以直接基于学习的无能功能的AI任务分析,而无需联合培训或额外的转换。尽管简单而直观,但Omni-ICM在多个基本愿景任务上大大优于现有的传统和基于学习的编解码器。
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布换人员重新识别(CC-REID)旨在在长时间匹配不同地点的同一个人,例如,超过日子,因此不可避免地满足换衣服的挑战。在本文中,我们专注于处理更具有挑战性的环境下的CC-Reid问题,即,只有一个图像,它可以实现高效和延迟的行人确定实时监控应用。具体而言,我们将步态识别作为辅助任务来驱动图像Reid模型来通过利用个人独特和独立布的步态信息来学习布不可知的表现,我们将此框架命名为Gi-Reid。 Gi-Reid采用两流架构,该架构由图像Reid-Stream和辅助步态识别流(步态流)组成。在推理的高计算效率中丢弃的步态流充当调节器,以鼓励在训练期间捕获捕获布不变的生物识别运动特征。为了从单个图像获取时间连续运动提示,我们设计用于步态流的步态序列预测(GSP)模块,以丰富步态信息。最后,为有效的知识正则化强制执行两个流的高级语义一致性。基于多种图像的布更换Reid基准测试的实验,例如LTCC,PRCC,Real28和VC衣服,证明了GI-REID对最先进的人来说。代码在https://github.com/jinx-ustc/gi -reid提供。
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Increasing research interests focus on sequential recommender systems, aiming to model dynamic sequence representation precisely. However, the most commonly used loss function in state-of-the-art sequential recommendation models has essential limitations. To name a few, Bayesian Personalized Ranking (BPR) loss suffers the vanishing gradient problem from numerous negative sampling and predictionbiases; Binary Cross-Entropy (BCE) loss subjects to negative sampling numbers, thereby it is likely to ignore valuable negative examples and reduce the training efficiency; Cross-Entropy (CE) loss only focuses on the last timestamp of the training sequence, which causes low utilization of sequence information and results in inferior user sequence representation. To avoid these limitations, in this paper, we propose to calculate Cumulative Cross-Entropy (CCE) loss over the sequence. CCE is simple and direct, which enjoys the virtues of painless deployment, no negative sampling, and effective and efficient training. We conduct extensive experiments on five benchmark datasets to demonstrate the effectiveness and efficiency of CCE. The results show that employing CCE loss on three state-of-the-art models GRU4Rec, SASRec, and S3-Rec can reach 125.63%, 69.90%, and 33.24% average improvement of full ranking NDCG@5, respectively. Using CCE, the performance curve of the models on the test data increases rapidly with the wall clock time, and is superior to that of other loss functions in almost the whole process of model training.
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In the scenario of black-box adversarial attack, the target model's parameters are unknown, and the attacker aims to find a successful adversarial perturbation based on query feedback under a query budget. Due to the limited feedback information, existing query-based black-box attack methods often require many queries for attacking each benign example. To reduce query cost, we propose to utilize the feedback information across historical attacks, dubbed example-level adversarial transferability. Specifically, by treating the attack on each benign example as one task, we develop a meta-learning framework by training a meta-generator to produce perturbations conditioned on benign examples. When attacking a new benign example, the meta generator can be quickly fine-tuned based on the feedback information of the new task as well as a few historical attacks to produce effective perturbations. Moreover, since the meta-train procedure consumes many queries to learn a generalizable generator, we utilize model-level adversarial transferability to train the meta-generator on a white-box surrogate model, then transfer it to help the attack against the target model. The proposed framework with the two types of adversarial transferability can be naturally combined with any off-the-shelf query-based attack methods to boost their performance, which is verified by extensive experiments.
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Supervised Deep-Learning (DL)-based reconstruction algorithms have shown state-of-the-art results for highly-undersampled dynamic Magnetic Resonance Imaging (MRI) reconstruction. However, the requirement of excessive high-quality ground-truth data hinders their applications due to the generalization problem. Recently, Implicit Neural Representation (INR) has appeared as a powerful DL-based tool for solving the inverse problem by characterizing the attributes of a signal as a continuous function of corresponding coordinates in an unsupervised manner. In this work, we proposed an INR-based method to improve dynamic MRI reconstruction from highly undersampled k-space data, which only takes spatiotemporal coordinates as inputs. Specifically, the proposed INR represents the dynamic MRI images as an implicit function and encodes them into neural networks. The weights of the network are learned from sparsely-acquired (k, t)-space data itself only, without external training datasets or prior images. Benefiting from the strong implicit continuity regularization of INR together with explicit regularization for low-rankness and sparsity, our proposed method outperforms the compared scan-specific methods at various acceleration factors. E.g., experiments on retrospective cardiac cine datasets show an improvement of 5.5 ~ 7.1 dB in PSNR for extremely high accelerations (up to 41.6-fold). The high-quality and inner continuity of the images provided by INR has great potential to further improve the spatiotemporal resolution of dynamic MRI, without the need of any training data.
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Recent studies have shown that using an external Language Model (LM) benefits the end-to-end Automatic Speech Recognition (ASR). However, predicting tokens that appear less frequently in the training set is still quite challenging. The long-tail prediction problems have been widely studied in many applications, but only been addressed by a few studies for ASR and LMs. In this paper, we propose a new memory augmented lookup dictionary based Transformer architecture for LM. The newly introduced lookup dictionary incorporates rich contextual information in training set, which is vital to correctly predict long-tail tokens. With intensive experiments on Chinese and English data sets, our proposed method is proved to outperform the baseline Transformer LM by a great margin on both word/character error rate and tail tokens error rate. This is achieved without impact on the decoding efficiency. Overall, we demonstrate the effectiveness of our proposed method in boosting the ASR decoding performance, especially for long-tail tokens.
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The objective of this paper is to learn dense 3D shape correspondence for topology-varying generic objects in an unsupervised manner. Conventional implicit functions estimate the occupancy of a 3D point given a shape latent code. Instead, our novel implicit function produces a probabilistic embedding to represent each 3D point in a part embedding space. Assuming the corresponding points are similar in the embedding space, we implement dense correspondence through an inverse function mapping from the part embedding vector to a corresponded 3D point. Both functions are jointly learned with several effective and uncertainty-aware loss functions to realize our assumption, together with the encoder generating the shape latent code. During inference, if a user selects an arbitrary point on the source shape, our algorithm can automatically generate a confidence score indicating whether there is a correspondence on the target shape, as well as the corresponding semantic point if there is one. Such a mechanism inherently benefits man-made objects with different part constitutions. The effectiveness of our approach is demonstrated through unsupervised 3D semantic correspondence and shape segmentation.
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Patients take care of what their teeth will be like after the orthodontics. Orthodontists usually describe the expectation movement based on the original smile images, which is unconvincing. The growth of deep-learning generative models change this situation. It can visualize the outcome of orthodontic treatment and help patients foresee their future teeth and facial appearance. While previous studies mainly focus on 2D or 3D virtual treatment outcome (VTO) at a profile level, the problem of simulating treatment outcome at a frontal facial image is poorly explored. In this paper, we build an efficient and accurate system for simulating virtual teeth alignment effects in a frontal facial image. Our system takes a frontal face image of a patient with visible malpositioned teeth and the patient's 3D scanned teeth model as input, and progressively generates the visual results of the patient's teeth given the specific orthodontics planning steps from the doctor (i.e., the specification of translations and rotations of individual tooth). We design a multi-modal encoder-decoder based generative model to synthesize identity-preserving frontal facial images with aligned teeth. In addition, the original image color information is used to optimize the orthodontic outcomes, making the results more natural. We conduct extensive qualitative and clinical experiments and also a pilot study to validate our method.
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