Local binary pattern (LBP) is a nonparametric descriptor, which efficiently summarizes the local structures of images. In recent years, it has aroused increasing interest in many areas of image processing and computer vision and has shown its effectiveness in a number of applications, in particular for facial image analysis, including tasks as diverse as face detection, face recognition, facial expression analysis, and demographic classification. This paper presents a comprehensive survey of LBP methodology, including several more recent variations. As a typical application of the LBP approach, LBP-based facial image analysis is extensively reviewed, while its successful extensions, which deal with various tasks of facial image analysis, are also highlighted.

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Local Binary Patterns and Its Application to Facial Image Analysis: A Survey

Superpixels: An evaluation of the state-of-the-art

The field of surveillance and forensics research is currently shifting focus and is now showing an ever increasing interest in the task of people reidentification. This is the task of assigning the same identifier to all instances of a particular individual captured in a series of images or videos, even after the occurrence of significant gaps over time or space. People reidentification can be a useful tool for people analysis in security as a data association method for long-term tracking in surveillance. However, current identification techniques being utilized present many difficulties and shortcomings. For instance, they rely solely on the exploitation of visual cues such as color, texture, and the object’s shape. Despite the many advances in this field, reidentification is still an open problem. This survey aims to tackle all the issues and challenging aspects of people reidentification while simultaneously describing the previously proposed solutions for the encountered problems. This begins with the first attempts of holistic descriptors and progresses to the more recently adopted 2D and 3D model-based approaches. The survey also includes an exhaustive treatise of all the aspects of people reidentification, including available datasets, evaluation metrics, and benchmarking.

People reidentification in surveillance and forensics: A survey

The interest of the research community in creating reference datasets for performance analysis is always very high. Although new datasets, collecting large amounts of video footage are spreading in surveillance and forensics, few bench-marks with annotation data are available for testing specific tasks and especially for 3D/multi-view analysis. In this paper we present 3DPeS, a new dataset for 3D/multi- view surveillance and forensic applications. This has been designed for discussing and evaluating research results in people re-identification and other related activities (people detection, people segmentation and people tracking). The new assessed version of the dataset contains hundreds of video sequences of 200 people taken from a multi-camera distributed surveillance system over several days, with different light conditions; each person is detected multiple times and from different points of view. In surveillance scenarios, the dataset can be exploited to evaluate people reacquisition, 3D body models and people activity reconstruction algorithms. In forensics it can be adopted too, by relaxing some constraints (e.g. real time) and neglecting some information (e.g. calibration). Some results on this new dataset are presented using state of the art methods for people re-identification as a benchmark for future comparisons.

3DPeS: 3D people dataset for surveillance and forensics

The capacity to recognize faces under varied poses is a fundamental human ability that presents a unique challenge for computer vision systems. Compared to frontal face recognition, which has been intensively studied and has gradually matured in the past few decades, Pose-Invariant Face Recognition (PIFR) remains a largely unsolved problem. However, PIFR is crucial to realizing the full potential of face recognition for real-world applications, since face recognition is intrinsically a passive biometric technology for recognizing uncooperative subjects. In this article, we discuss the inherent difficulties in PIFR and present a comprehensive review of established techniques. Existing PIFR methods can be grouped into four categories, that is, pose-robust feature extraction approaches, multiview subspace learning approaches, face synthesis approaches, and hybrid approaches. The motivations, strategies, pros/cons, and performance of representative approaches are described and compared. Moreover, promising directions for future research are discussed.

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A Comprehensive Survey on Pose-Invariant Face Recognition

Superpixel segmentation has become a popular preprocessing step in computer vision with a great variety of existing algorithms. Almost all algorithms claim to compute compact superpixels, but no one showed how to measure compactness and no one investigated the implications. In this paper, we propose a novel metric to measure superpixel compactness. With this metric, we show that there is a trade-off between compactness and boundary recall. In addition, we propose an algorithm that allows to precicely control this trade-off and that outperforms the current state-of-the-art. As a demonstration, we show the importance of considering compactness with the help of an example application.

Measuring and evaluating the compactness of superpixels

In this paper, we study the use of facial appearancefeatures for the re-identification of persons using distributedcamera networks in a realistic surveillance scenario.In contrast to features commonly used for person reidentification,such as whole body appearance, facial featuresoffer the advantage of remaining stable over muchlarger intervals of time. The challenge in using faces forsuch applications, apart from low captured face resolutions,is that their appearance across camera sightings is largelyinfluenced by lighting and viewing pose. Here, a numberof techniques to address these problems are presented andevaluated on a database of surveillance-type recordings. Asystem for online capture and interactive retrieval is presentedthat allows to search for sightings of particular personsin the video database. Evaluation results are presentedon surveillance data recorded with four cameras over severaldays. A mean average precision of 0.60 was achievedfor inter-camera retrieval using just a single track as queryset, and up to 0.86 after relevance feedback by an operator.

/pdf/multi-pose-face-recognition-for-person-retrieval-in-camera-4l2rya05c4.pdf

Multi-pose Face Recognition for Person Retrieval in Camera Networks

In this paper an overview of face recognition research activities at the interACT Research Center is given. The face recognition efforts at the interACT Research Center consist of development of a fast and robust face recognition algorithm and fully automatic face recognition systems that can be deployed for real-life smart interaction applications. The face recognition algorithm is based on appearances of local facial regions that are represented with discrete cosine transform coefficients. Three fully automatic face recognition systems have been developed that are based on this algorithm. The first one is the "door monitoring system" that observes the entrance of a room and identifies the subjects while they are entering the room. The second one is the "portable face recognition system" that aims at environment-free face recognition and recognizes the user of a machine. The third system, "3D face recognition system", performs fully automatic face recognition on 3D range data.

http://www.quaero.org/media/files/bibliographie/uka_qpr6_face_reco_icb09_demo.pdf

Face Recognition for Smart Interactions

An evaluation of the compactness of superpixels

In this paper, we present a detailed analysis of multimodal fusion for person identification in a smart environment. The multi-modal system consists of a video-based face recognition system and a speaker identification system. We investigated different score normalization, modality weighting and modality combination schemes during the fusion of the individual modalities. We introduced two new modality weighting schemes, namely, the cumulative ratio of correct matches (CRCM) and distance-to-second-closest (DT2ND) measures. In addition, we also assessed the effects of the well-known score normalization and classifier combination methods on the identification performance. Experimental results obtained on the CLEAR 2007 evaluation corpus, which contains audio-visual recordings from different smart rooms, show that CRCM-based modality weighting improves the correct identification rates significantly.

Mika Fischer

Papers

Measuring and evaluating the compactness of superpixels

Multi-pose Face Recognition for Person Retrieval in Camera Networks

Face Recognition for Smart Interactions

An evaluation of the compactness of superpixels

Multi-modal Person Identification in a Smart Environment