Enhancing person annotation for personal photo management using content and context based technologies

Rapid technological growth and the decreasing cost of photo capture means that we are all taking more digital photographs than ever before. However, lack of technology for automatically organising personal photo archives has resulted in many users left with poorly annotated photos, causing them great frustration when such photo collections are to be browsed or searched at a later time. As a result, there has recently been significant research interest in technologies for supporting effective annotation. This thesis addresses an important sub-problem of the broad annotation problem, namely "person annotation" associated with personal digital photo management. Solutions to this problem are provided using content analysis tools in combination with context data within the experimental photo management framework, called “MediAssist”. Readily available image metadata, such as location and date/time, are captured from digital cameras with in-built GPS functionality, and thus provide knowledge about when and where the photos were taken. Such information is then used to identify the "real-world" events corresponding to certain activities in the photo capture process. The problem of enabling effective person annotation is formulated in such a way that both "within-event" and "cross-event" relationships of persons' appearances are captured. The research reported in the thesis is built upon a firm foundation of content-based analysis technologies, namely face detection, face recognition, and body-patch matching together with data fusion. Two annotation models are investigated in this thesis, namely progressive and non-progressive. The effectiveness of each model is evaluated against varying proportions of initial annotation, and the type of initial annotation based on individual and combined face, body-patch and person-context information sources. The results reported in the thesis strongly validate the use of multiple information sources for person annotation whilst emphasising the advantage of event-based photo analysis in real-life photo management systems

Face Detection and Verification using Local Binary Patterns

This thesis proposes a robust Automatic Face Verification (AFV) system using Local Binary Patterns (LBP). AFV is mainly composed of two modules: Face Detection (FD) and Face Verification (FV). The purpose of FD is to determine whether there are any face in an image, while FV involves confirming or denying the identity claimed by a person. The contributions of this thesis are the following: 1) a real-time multiview FD system which is robust to illumination and partial occlusion, 2) a FV system based on the adaptation of LBP features, 3) an extensive study of the performance evaluation of FD algorithms and in particular the effect of FD errors on FV performance. The first part of the thesis addresses the problem of frontal FD. We introduce the system of Viola and Jones which is the first real-time frontal face detector. One of its limitations is the sensitivity to local lighting variations and partial occlusion of the face. In order to cope with these limitations, we propose to use LBP features. Special emphasis is given to the scanning process and to the merging of overlapped detections, because both have a significant impact on the performance. We then extend our frontal FD module to multiview FD. In the second part, we present a novel generative approach for FV, based on an LBP description of the face. The main advantages compared to previous approaches are a very fast and simple training procedure and robustness to bad lighting conditions. In the third part, we address the problem of estimating the quality of FD. We first show the influence of FD errors on the FV task and then empirically demonstrate the limitations of current detection measures when applied to this task. In order to properly evaluate the performance of a face detection module, we propose to embed the FV into the performance measuring process. We show empirically that the proposed methodology better matches the final FV performance