This paper addresses the problem of discovering the objects present in a collection of images without any supervision. We build on the optimization approach of Vo {\em et al.}~\cite{Vo2019UnsupOptim} with several key novelties: (1) We propose a novel saliency-based region proposal algorithm that achieves significantly higher overlap with ground-truth objects than other competitive methods. This procedure leverages off-the-shelf CNN features trained on classification tasks without any bounding box information, but is otherwise unsupervised. (2) We exploit the inherent hierarchical structure of proposals as an effective regularizer for the approach to object discovery of~\cite{Vo2019UnsupOptim}, boosting its performance to significantly improve over the state of the art on several standard benchmarks. (3) We adopt a two-stage strategy to select promising proposals using small random sets of images before using the whole image collection to discover the objects it depicts, allowing us to tackle, for the first time (to the best of our knowledge), the discovery of multiple objects in each one of the pictures making up datasets with up to 20,000 images, an over five-fold increase compared to existing methods, and a first step toward true large-scale unsupervised image interpretation.

该论文提出了一个基于无监督学习的物体发现方法，其中包括了基于显著性的边界提取算法以及采用层次结构与两阶段策略提高发现效率。通过使用小型随机图片集和整个图片集合，该方法能够发现每张图片中的多个目标，实现了对面向真实大规模图像数据集的无监督图像解释的重要的一步。

面向大规模图像集合的无监督多目标发现