Context-aware person identification in personal photo collections

Identifying the people in photos is an important need for users of photo management systems. We present MediAssist, one such system which facilitates browsing, searching and semi-automatic annotation of personal photos, using analysis of both image content and the context in which the photo is captured. This semi-automatic annotation includes annotation of the identity of people in photos. In this paper, we focus on such person annotation, and propose person identification techniques based on a combination of context and content. We propose language modelling and nearest neighbor approaches to context-based person identification, in addition to novel face color and image color content-based features (used alongside face recognition and body patch features). We conduct a comprehensive empirical study of these techniques using the real private photo collections of a number of users, and show that combining context- and content-based analysis improves performance over content or context alone

Methods for automatic and assisted image annotation

Personal memories composed of digital pictures are very popular at the moment. To retrieve these media items annotation is required. During the last years, several approaches have been proposed in order to overcome the image annotation problem. This paper presents our proposals to address this problem. Automatic and semi-automatic learning methods for semantic concepts are presented. The automatic method is based on semantic concepts estimated using visual content, context metadata and audio information. The semi-automatic method is based on results provided by a computer game. The paper describes our proposals and presents their evaluations

Multiview Semi-Supervised Ranking for Automatic Image Annotation

International audienceMost photo sharing sites give their users the opportunity to manually label images. The labels collected that way are usually very incomplete due to the size of the image collections: most images are not labeled according to all the categories they belong to, and, conversely, many class have relatively few representative examples. Automated image systems that can deal with small amounts of labeled examples and unbalanced classes are thus necessary to better organize and annotate images. In this work, we propose a multiview semi-supervised bipartite ranking model which allows to leverage the information contained in unlabeled sets of images in order to improve the prediction performance, using multiple descriptions, or views of images. For each topic class, our approach first learns as many view-specific rankers as available views using the labeled data only. These rankers are then improved iteratively by adding pseudo-labeled pairs of examples on which all view-specific rankers agree over the ranking of examples within these pairs. We report on experiments carried out on the NUS-WIDE dataset, which show that the multiview ranking process improves predictive performances when a small number of labeled examples is available specially for unbalanced classes. We show also that our approach achieves significant improvements over a state-of the art semi-supervised multiview classification model

Image annotation with Photocopain

Photo annotation is a resource-intensive task, yet is increasingly essential as image archives and personal photo collections grow in size. There is an inherent conflict in the process of describing and archiving personal experiences, because casual users are generally unwilling to expend large amounts of effort on creating the annotations which are required to organise their collections so that they can make best use of them. This paper describes the Photocopain system, a semi-automatic image annotation system which combines information about the context in which a photograph was captured with information from other readily available sources in order to generate outline annotations for that photograph that the user may further extend or amend

IMAGE MANAGEMENT USING PATTERN RECOGNITION SYSTEMS

With the popular usage of personal image devices and the continued increase of computing power, casual users need to handle a large number of images on computers. Image management is challenging because in addition to searching and browsing textual metadata, we also need to address two additional challenges. First, thumbnails, which are representative forms of original images, require significant screen space to be represented meaningfully. Second, while image metadata is crucial for managing images, creating metadata for images is expensive. My research on these issues is composed of three components which address these problems. First, I explore a new way of browsing a large number of images. I redesign and implement a zoomable image browser, PhotoMesa, which is capable of showing thousands of images clustered by metadata. Combined with its simple navigation strategy, the zoomable image environment allows users to scale up the size of an image collection they can comfortably browse. Second, I examine tradeoffs of displaying thumbnails in limited screen space. While bigger thumbnails use more screen space, smaller thumbnails are hard to recognize. I introduce an automatic thumbnail cropping algorithm based on a computer vision saliency model. The cropped thumbnails keep the core informative part and remove the less informative periphery. My user study shows that users performed visual searches more than 18% faster with cropped thumbnails. Finally, I explore semi-automatic annotation techniques to help users make accurate annotations with low effort. Automatic metadata extraction is typically fast but inaccurate while manual annotation is slow but accurate. I investigate techniques to combine these two approaches. My semi-automatic annotation prototype, SAPHARI, generates image clusters which facilitate efficient bulk annotation. For automatic clustering, I present hierarchical event clustering and clothing based human recognition. Experimental results demonstrate the effectiveness of the semi-automatic annotation when applied on personal photo collections. Users were able to make annotation 49% and 6% faster with the semi-automatic annotation interface on event and face tasks, respectively

Annotating Object Instances with a Polygon-RNN

We propose an approach for semi-automatic annotation of object instances. While most current methods treat object segmentation as a pixel-labeling problem, we here cast it as a polygon prediction task, mimicking how most current datasets have been annotated. In particular, our approach takes as input an image crop and sequentially produces vertices of the polygon outlining the object. This allows a human annotator to interfere at any time and correct a vertex if needed, producing as accurate segmentation as desired by the annotator. We show that our approach speeds up the annotation process by a factor of 4.7 across all classes in Cityscapes, while achieving 78.4% agreement in IoU with original ground-truth, matching the typical agreement between human annotators. For cars, our speed-up factor is 7.3 for an agreement of 82.2%. We further show generalization capabilities of our approach to unseen datasets