Many standard computer vision datasets exhibit biases due to a variety of sources including illumination condition, imaging system, and preference of dataset collectors. Biases like these can have downstream effects in the use of vision datasets in the construction of generalizable techniques, especially for the goal of the creation of a classification system capable of generalizing to unseen and novel datasets. In this work we propose Unbiased Metric Learning (UML), a metric learning approach, to achieve this goal. UML operates in the following two steps: (1) By varying hyperparameters, it learns a set of less biased candidate distance metrics on training examples from multiple biased datasets. The key idea is to learn a neighborhood for each example, which consists of not only examples of the same category from the same dataset, but those from other datasets. The learning framework is based on structural SVM. (2) We do model validation on a set of weakly-labeled web images retrieved by issuing class labels as keywords to search engine. The metric with best validation performance is selected. Although the web images sometimes have noisy labels, they often tend to be less biased, which makes them suitable for the validation set in our task. Cross-dataset image classification experiments are carried out. Results show significant performance improvement on four well-known computer vision datasets.

Domain adaptation is an important emerging topic in computer vision. In this paper, we present one of the first studies of domain shift in the context of object recognition. We introduce a method that adapts object models acquired in a particular visual domain to new imaging conditions by learning a transformation that minimizes the effect of domain-induced changes in the feature distribution. The transformation is learned in a supervised manner and can be applied to categories for which there are no labeled examples in the new domain. While we focus our evaluation on object recognition tasks, the transform-based adaptation technique we develop is general and could be applied to non-image data. Another contribution is a new multi-domain object database, freely available for download. We experimentally demonstrate the ability of our method to improve recognition on categories with few or no target domain labels and moderate to large changes in the imaging conditions.

Despite significant progress in object categorization, in recent years, a number of important challenges remain; mainly, the ability to learn from limited labeled data and to recognize object classes within large, potentially open, set of labels. Zero-shot learning is one way of addressing these challenges, but it has only been shown to work with limited sized class vocabularies and typically requires separation between supervised and unsupervised classes, allowing former to inform the latter but not vice versa. We propose the notion of vocabulary-informed learning to alleviate the above mentioned challenges and address problems of supervised, zero-shot, generalized zero-shot and open set recognition using a unified framework. Specifically, we propose a weighted maximum margin framework for semantic manifold-based recognition that incorporates distance constraints from (both supervised and unsupervised) vocabulary atoms. Distance constraints ensure that labeled samples are projected closer to their correct prototypes, in the embedding space, than to others. We illustrate that resulting model shows improvements in supervised, zero-shot, generalized zero-shot, and large open set recognition, with up to 310K class vocabulary on Animal with Attributes and ImageNet datasets.

The accuracy of k-nearest neighbor (kNN) classification depends significantly on the metric used to compute distances between different examples. In this paper, we show how to learn a Mahalanobis distance metric for kNN classification from labeled examples. The Mahalanobis metric can equivalently be viewed as a global linear transformation of the input space that precedes kNN classification using Euclidean distances. In our approach, the metric is trained with the goal that the k-nearest neighbors always belong to the same class while examples from different classes are separated by a large margin. As in support vector machines (SVMs), the margin criterion leads to a convex optimization based on the hinge loss. Unlike learning in SVMs, however, our approach requires no modification or extension for problems in multiway (as opposed to binary) classification. In our framework, the Mahalanobis distance metric is obtained as the solution to a semidefinite program. On several data sets of varying size and difficulty, we find that metrics trained in this way lead to significant improvements in kNN classification. Sometimes these results can be further improved by clustering the training examples and learning an individual metric within each cluster. We show how to learn and combine these local metrics in a globally integrated manner.

The problem of domain generalization is to take knowledge acquired from a number of related domains where training data is available, and to then successfully apply it to previously unseen domains. We propose a new feature learning algorithm, Multi-Task Autoencoder (MTAE), that provides good generalization performance for crossdomain object recognition.Our algorithm extends the standard denoising autoencoder framework by substituting artificially induced corruption with naturally occurring inter-domain variability in the appearance of objects. Instead of reconstructing images from noisy versions, MTAE learns to transform the original image into analogs in multiple related domains. It thereby learns features that are robust to variations across domains. The learnt features are then used as inputs to a classifier.We evaluated the performance of the algorithm on benchmark image recognition datasets, where the task is to learn features from multiple datasets and to then predict the image label from unseen datasets. We found that (denoising) MTAE outperforms alternative autoencoder-based models as well as the current state-of-the-art algorithms for domain generalization.

The PASCAL Visual Object Classes (VOC) challenge is a benchmark in visual object category recognition and detection, providing the vision and machine learning communities with a standard dataset of images and annotation, and standard evaluation procedures. Organised annually from 2005 to present, the challenge and its associated dataset has become accepted as the benchmark for object detection.This paper describes the dataset and evaluation procedure. We review the state-of-the-art in evaluated methods for both classification and detection, analyse whether the methods are statistically different, what they are learning from the images (e.g. the object or its context), and what the methods find easy or confuse. The paper concludes with lessons learnt in the three year history of the challenge, and proposes directions for future improvement and extension.

深度学习的最新进展依赖于大型标签的数据集来培训大容量模型。但是，以时间和成本效益的方式收集大型数据集通常会导致标签噪声。我们提出了一种从嘈杂的标签中学习的方法，该方法利用特征空间中的训练示例之间的相似性，鼓励每个示例的预测与其最近的邻居相似。与使用多个模型或不同阶段的训练算法相比，我们的方法采用了简单，附加的正规化项的形式。它可以被解释为经典的，偏置标签传播算法的归纳版本。我们在数据集上彻底评估我们的方法评估合成（CIFAR-10，CIFAR-100）和现实（迷你网络，网络vision，Clotsing1m，Mini-Imagenet-Red）噪声，并实现竞争性或最先进的精度，在所有人之间。

Jain等人引入的倾向模型。2016年已成为处理极端多标签分类（XMLC）中缺失和长尾标签的标准方法。在本文中，我们对这种方法进行批判性修订，表明尽管具有理论性，但其在当代XMLC作品中的应用仍是有争议的。我们详尽地讨论了基于倾向的方法的缺陷，并提出了几种食谱，其中一些与搜索引擎和推荐系统中使用的解决方案有关，我们认为这构成了XMLC中遵循的有希望的替代方案。

监督学习的关键假设是培训和测试数据遵循相同的概率分布。然而，这种基本假设在实践中并不总是满足，例如，由于不断变化的环境，样本选择偏差，隐私问题或高标签成本。转移学习（TL）放松这种假设，并允许我们在分销班次下学习。通常依赖于重要性加权的经典TL方法 - 基于根据重要性（即测试过度训练密度比率）的训练损失培训预测器。然而，由于现实世界机器学习任务变得越来越复杂，高维和动态，探讨了新的新方法，以应对这些挑战最近。在本文中，在介绍基于重要性加权的TL基础之后，我们根据关节和动态重要预测估计审查最近的进步。此外，我们介绍一种因果机制转移方法，该方法包含T1中的因果结构。最后，我们讨论了TL研究的未来观点。

The ImageNet Large Scale Visual Recognition Challenge is a benchmark in object category classification and detection on hundreds of object categories and millions of images. The challenge has been run annually from 2010 to present, attracting participation from more than fifty institutions. This paper describes the creation of this benchmark dataset and the advances in object recognition that have been possible as a result. We discuss the chal-

We build new test sets for the CIFAR-10 and ImageNet datasets. Both benchmarks have been the focus of intense research for almost a decade, raising the danger of overfitting to excessively re-used test sets. By closely following the original dataset creation processes, we test to what extent current classification models generalize to new data. We evaluate a broad range of models and find accuracy drops of 3% -15% on CIFAR-10 and 11% -14% on ImageNet. However, accuracy gains on the original test sets translate to larger gains on the new test sets. Our results suggest that the accuracy drops are not caused by adaptivity, but by the models' inability to generalize to slightly "harder" images than those found in the original test sets.

我们提出了一个统一的查看，即通过通用表示，一个深层神经网络共同学习多个视觉任务和视觉域。同时学习多个问题涉及最大程度地减少具有不同幅度和特征的多个损失函数的加权总和，从而导致一个损失的不平衡状态，与学习每个问题的单独模型相比，一个损失的不平衡状态主导了优化和差的结果。为此，我们提出了通过小容量适配器将多个任务/特定于域网络的知识提炼到单个深神经网络中的知识。我们严格地表明，通用表示在学习NYU-V2和CityScapes中多个密集的预测问题方面实现了最新的表现，来自视觉Decathlon数据集中的不同域中的多个图像分类问题以及MetadataSet中的跨域中的几个域中学习。最后，我们还通过消融和定性研究进行多次分析。

We study the problem of object recognition for categories for which we have no training examples, a task also called zero-data or zero-shot learning. This situation has hardly been studied in computer vision research, even though it occurs frequently; the world contains tens of thousands of different object classes, and image collections have been formed and suitably annotated for only a few of them. To tackle the problem, we introduce attribute-based classification: Objects are identified based on a high-level description that is phrased in terms of semantic attributes, such as the object's color or shape. Because the identification of each such property transcends the specific learning task at hand, the attribute classifiers can be prelearned independently, for example, from existing image data sets unrelated to the current task. Afterward, new classes can be detected based on their attribute representation, without the need for a new training phase. In this paper, we also introduce a new data set, Animals with Attributes, of over 30,000 images of 50 animal classes, annotated with 85 semantic attributes. Extensive experiments on this and two more data sets show that attribute-based classification indeed is able to categorize images without access to any training images of the target classes.

零拍摄对象检测（ZSD），将传统检测模型扩展到检测来自Unseen类别的对象的任务，已成为计算机视觉中的新挑战。大多数现有方法通过严格的映射传输策略来解决ZSD任务，这可能导致次优ZSD结果：1）这些模型的学习过程忽略了可用的看不见的类信息，因此可以轻松地偏向所看到的类别; 2）原始视觉特征空间并不合适，缺乏歧视信息。为解决这些问题，我们开发了一种用于ZSD的新型语义引导的对比网络，命名为Contrastzsd，一种检测框架首先将对比学习机制带入零拍摄检测的领域。特别地，对比度包括两个语义导向的对比学学习子网，其分别与区域类别和区域区域对之间形成对比。成对对比度任务利用从地面真理标签和预定义的类相似性分布派生的附加监督信号。在那些明确的语义监督的指导下，模型可以了解更多关于看不见的类别的知识，以避免看到概念的偏见问题，同时优化视觉功能的数据结构，以更好地辨别更好的视觉语义对齐。广泛的实验是在ZSD，即Pascal VOC和MS Coco的两个流行基准上进行的。结果表明，我们的方法优于ZSD和广义ZSD任务的先前最先进的。

机器学习模型通常会遇到与训练分布不同的样本。无法识别分布（OOD）样本，因此将该样本分配给课堂标签会显着损害模​​型的可靠性。由于其对在开放世界中的安全部署模型的重要性，该问题引起了重大关注。由于对所有可能的未知分布进行建模的棘手性，检测OOD样品是具有挑战性的。迄今为止，一些研究领域解决了检测陌生样本的问题，包括异常检测，新颖性检测，一级学习，开放式识别识别和分布外检测。尽管有相似和共同的概念，但分别分布，开放式检测和异常检测已被独立研究。因此，这些研究途径尚未交叉授粉，创造了研究障碍。尽管某些调查打算概述这些方法，但它们似乎仅关注特定领域，而无需检查不同领域之间的关系。这项调查旨在在确定其共同点的同时，对各个领域的众多著名作品进行跨域和全面的审查。研究人员可以从不同领域的研究进展概述中受益，并协同发展未来的方法。此外，据我们所知，虽然进行异常检测或单级学习进行了调查，但没有关于分布外检测的全面或最新的调查，我们的调查可广泛涵盖。最后，有了统一的跨域视角，我们讨论并阐明了未来的研究线，打算将这些领域更加紧密地融为一体。

仅使用图像级注释的弱监督对象检测（WSOD）在过去几年中引起了不断增长的关注。然而，此类任务通常以专注于自然图像的特定于域的解决方案，而我们表明应用于预先训练的深度特征的简单多实例方法会产生优异的非摄影数据集的性能，可能包括新类。该方法不包括任何微调或跨域学习，因此有效且可能适用于任意数据集和类。我们调查了拟议方法的几种口味，一些包括多层的Perceptron和多层分类器。尽管其简单性，我们的方法在一系列公开的数据集中展示了竞争结果，包括绘画（人民艺术，象征），水彩画，剪贴画和漫画，并允许快速学习未经看的视觉类别。

Transfer learning aims at improving the performance of target learners on target domains by transferring the knowledge contained in different but related source domains. In this way, the dependence on a large number of target domain data can be reduced for constructing target learners. Due to the wide application prospects, transfer learning has become a popular and promising area in machine learning. Although there are already some valuable and impressive surveys on transfer learning, these surveys introduce approaches in a relatively isolated way and lack the recent advances in transfer learning. Due to the rapid expansion of the transfer learning area, it is both necessary and challenging to comprehensively review the relevant studies. This survey attempts to connect and systematize the existing transfer learning researches, as well as to summarize and interpret the mechanisms and the strategies of transfer learning in a comprehensive way, which may help readers have a better understanding of the current research status and ideas. Unlike previous surveys, this survey paper reviews more than forty representative transfer learning approaches, especially homogeneous transfer learning approaches, from the perspectives of data and model. The applications of transfer learning are also briefly introduced. In order to show the performance of different transfer learning models, over twenty representative transfer learning models are used for experiments. The models are performed on three different datasets, i.e., Amazon Reviews, Reuters-21578, and Office-31. And the experimental results demonstrate the importance of selecting appropriate transfer learning models for different applications in practice.

Object detection performance, as measured on the canonical PASCAL VOC dataset, has plateaued in the last few years. The best-performing methods are complex ensemble systems that typically combine multiple low-level image features with high-level context. In this paper, we propose a simple and scalable detection algorithm that improves mean average precision (mAP) by more than 30% relative to the previous best result on VOC 2012-achieving a mAP of 53.3%. Our approach combines two key insights:(1) one can apply high-capacity convolutional neural networks (CNNs) to bottom-up region proposals in order to localize and segment objects and (2) when labeled training data is scarce, supervised pre-training for an auxiliary task, followed by domain-specific fine-tuning, yields a significant performance boost. Since we combine region proposals with CNNs, we call our method R-CNN: Regions with CNN features. We also compare R-CNN to OverFeat, a recently proposed sliding-window detector based on a similar CNN architecture. We find that R-CNN outperforms OverFeat by a large margin on the 200-class ILSVRC2013 detection dataset. Source code for the complete system is available at http://www.cs.berkeley.edu/ ˜rbg/rcnn.

旨在概括在源域中训练的模型来看不见的目标域，域泛化（DG）最近引起了很多关注。 DG的关键问题是如何防止对观察到的源极域的过度接收，因为在培训期间目标域不可用。我们调查过度拟合不仅导致未经看不见的目标域的普遍推广能力，而且在测试阶段导致不稳定的预测。在本文中，我们观察到，在训练阶段采样多个任务并在测试阶段产生增强图像，很大程度上有利于泛化性能。因此，通过处理不同视图的任务和图像，我们提出了一种新颖的多视图DG框架。具体地，在训练阶段，为了提高泛化能力，我们开发了一种多视图正则化元学习算法，该算法采用多个任务在更新模型期间产生合适的优化方向。在测试阶段，为了减轻不稳定的预测，我们利用多个增强图像来产生多视图预测，这通过熔断测试图像的不同视图的结果显着促进了模型可靠性。三个基准数据集的广泛实验验证了我们的方法优于几种最先进的方法。

域的概括旨在学习一个通用模型，该模型在看不见的目标域上表现良好，并结合了来自多个源域的知识。在这项研究中，我们考虑了以下场景，在不同类别跨领域的条件分布之间发生不同的领域变化。当源域中的标记样品受到限制时，现有方法不足以鲁棒。为了解决这个问题，我们提出了一个新型的域泛化框架，称为Wasserstein分布在鲁棒域的概括（WDRDG），灵感来自分布稳健优化的概念。我们鼓励对特定于类的Wasserstein不确定性集中有条件分布的鲁棒性，并优化分类器在这些不确定性集上的最差性能。我们进一步开发了一个测试时间适应模块，利用最佳运输来量化未见目标域和源域之间的关系，以使目标数据适应性推断。旋转MNIST，PACS和VLCS数据集的实验表明，我们的方法可以有效地平衡挑战性概括场景中的鲁棒性和可区分性。