Instance search based on weakly supervised feature learning

Instance search has been conventionally addressed as an image retrieval issue. In the existing solutions, traditional hand-crafted features and global deep features have been widely adopted. Unfortunately, since the features are not directly derived from the exact area of an instance in an image, satisfactory performance from most of them is undesirable. In this paper, a compact instance level feature representation is proposed. The scheme basically consists of two convolutional neural network (CNN) pipelines. One is designed for localizing potential instances from an image, while another is trained to learn object-aware weights to produce distinctive features. The sensitivity to the unknown categories, the distinctiveness to different instances, and most importantly, the capability of localizing an instance in an image are all carefully considered in the feature design. Moreover, both pipelines only require image level annotations, which makes the framework feasible for large-scale image collections with variety of instances. To the best of our knowledge, this is the first piece of work that builds the instance level representation based on weakly supervised object detection. (c) 2019 Elsevier B.V. All rights reserved.