People identification and tracking through fusion of facial and gait features

This paper reviews the contemporary (face, gait, and fusion) computational approaches for automatic human identification at a distance. For remote identification, there may exist large intra-class variations that can affect the performance of face/gait systems substantially. First, we review the face recognition algorithms in light of factors, such as illumination, resolution, blur, occlusion, and pose. Then we introduce several popular gait feature templates, and the algorithms against factors such as shoe, carrying condition, camera view, walking surface, elapsed time, and clothing. The motivation of fusing face and gait, is that, gait is less sensitive to the factors that may affect face (e.g., low resolution, illumination, facial occlusion, etc.), while face is robust to the factors that may affect gait (walking surface, clothing, etc.). We review several most recent face and gait fusion methods with different strategies, and the significant performance gains suggest these two modality are complementary for human identification at a distance

People identification and tracking through fusion of facial and gait features

This paper reviews the contemporary (face, gait, and fusion) computational approaches for automatic human identification at a distance. For remote identification, there may exist large intra-class variations that can affect the performance of face/gait systems substantially. First, we review the face recognition algorithms in light of factors, such as illumination, resolution, blur, occlusion, and pose. Then we introduce several popular gait feature templates, and the algorithms against factors such as shoe, carrying condition, camera view, walking surface, elapsed time, and clothing. The motivation of fusing face and gait, is that, gait is less sensitive to the factors that may affect face (e.g., low resolution, illumination, facial occlusion, etc.), while face is robust to the factors that may affect gait (walking surface, clothing, etc.). We review several most recent face and gait fusion methods with different strategies, and the significant performance gains suggest these two modality are complementary for human identification at a distance

Gaıt-Based Gender Classıfıcatıon Usıng Neutral And Non-Neutral Gaıt Sequences

Nötr veya Nötr Olmayan Ardaşık Yürüyüş Tarzlarından Davranış-bağımlı Cinsiyet Klasifikasyonu Biometrik sistem bireyle özleĢik en çok göze çarpan bir özellik veya niteliğe dayalı bir vasıf kullanılarak bireyin tanımlanmasını sağlar. Biometric tanımlayıcılar genellikle davranıĢsal özelliklere karĢı fizyolojik özellikler olarak kategorize edilir. Fizyolojik özellikler Ģahsın parmak izi, avuç içi damarlar, yüz tanıma gibi vücudun yapısal özellikleriyle ilgili olmasına karĢın, Ģahsın davranıĢsal özellikleri yürüme tarzı, imzası ve sesiyle ilgili vasıflarıdır. YürüyüĢ tarzı biometrik tanımlama yöntemi ile kiĢilerin erkek veya kadın olduğunun tanımlamasında kullanılacağı gibi kiĢilerin yürüyüĢ tarzları, yetkisiz kiĢilerin ve cinsiyetlerin belirlenmesi, ve yürüme veya yürümeye bağlı anormalliklerin tespiti gibi farklı uygulama alanlarında kullanılabilir. Bu tezde, kiĢilerin yürüyüĢ özelliklerine göre cinsiyet sınıflandırması yapan bir yöntem önerilmiĢtir. Nötr yürüyüĢ dizilerinin yanı sıra palto/manto giyme (CW) ve çanta taĢıma (CB) gibi nötr olmayan yürüyüĢ tarzlarından kaynaklanan tanımlama sorunları araĢtırılmıĢtır. Cinsiyet sınıflandırma amacıyla farklı yürüyüĢ tarzı dizinlerinin araĢtırılması ve denemelerinin yapılması üzerinde durulmuĢtur. Sayısal denemeler Casia B veritabanında mevcut değiĢik yürüyüĢ tarzları üzerinde çok sayıda denek üzerinde yapılmıĢtır. Bu veritabaında 11 farklı görünüm açılarından kaydedilen 124 kiĢi (31 kadın ve 93 erkek) bulunmaktadır. Her bir denek için, 6 nötr (Nu), 2 adet manto/palto giyme (CW) ve 2 adet çanta taĢıma (CB) olmak üzere 10 yürüme dizini bulunmaktadır. Önerilen yöntemin ilk bölümünde bir çerçeveli görüntüden arka planı çıkarma yöntemi kullanarak sırasal çerçeveli görüntüler ile arka planı arasındaki farkın hesaplaması üzerinde durulmuĢtur. Ġkinci bölümde YürüyüĢ Enerjisi (Gait Energy) görüntü özelliklikleri yardımıyla sınıflandırma yöntemi incelenmiĢtir. Son olarak bu çalıĢmada bir sınıflandırma aracı olarak Yürüme Enerjisi Görüntü (Gait Energy Image) ve Rastgele Yürüme Enerji Görüntü (Gait Entropy Enerji Image, GEnEI) yöntemlri uygulanmıĢtır. Wavelet Transformasyon tekniği ve GEnEI yöntemi kullanılarakveritabanından üç farklı yürüyüĢ tarzı özellikli görüntü grubu kurgulanmıĢtır. Bu yürüyüĢ tarzı özellikli görüntü grupları: (i) YaklaĢık Katsayı Rastgele Yürüme Enerji Görüntü (Approximate coefficient Energy Image, AGEnEI), (ii) Diksel Katsayı Rastgele Yürüme Enerji Görüntü (Vertical coefficient Energy Image, VGEnEI), ve (iii) her ikisinin birleĢkesi olan YaklaĢık ve Diksel Katsayı Yürüme Enerji Görüntü (Approximate coefficient Energy Image and Vertical coefficient Energy Image, AVGEnEI). Yukarıda belirtilen görüntüleme iĢlemlerinin iĢlevliliğinin denemesi için k-derece yakın komĢu (k-Neraest Neighboor, k-NN) ve destek vector makinası (Support vector Machine, SVM) olarak bilinen yöntemler önerilmiĢtir. Ayrıca yukarıda belirtilen üç tür enerji görüntü yöntemi birleĢtirme tabanlı karar verme (fuse-based decirion level fusion) yöntemi kullanılarak da denenmiĢtir. Sınıflandırmada k-NN yöntemi ile Nu gait dizinleri için AGEnEI % 97 lik ergitme seviyesini (fusion level), VGEnEI CB dizinleri için 91.4% lik ergitme seviyesini, ve AGEnEI CW dizinleri için %83.4 ergitme seviyesi sonuçları bulunmuĢtur. k=1, 3 ve 5 sayıları ile belirlenen üç ayrı özellik grubu arasında k=1 dikkate değer ergitme seviyesi sonuçları vermiĢtir. Her üç enerji görüntüleme yöntemi (Energy Entropy Image) „Decision-fusion‟ yöntemi ile birleĢtirildiğinde (fused) ergitme dereceleri Nu için %99.8, CB için %92.2 ve for CW için 86.3% dir. Bu sonuçlar her bir özelliğin ayrı ayrı ele alındığı durumunda elede edilen sonuçlardan daha iyi olduğu dikkate değerdir.

Robust gait recognition under variable covariate conditions

PhDGait is a weak biometric when compared to face, fingerprint or iris because it can be easily affected by various conditions. These are known as the covariate conditions and include clothing, carrying, speed, shoes and view among others. In the presence of variable covariate conditions gait recognition is a hard problem yet to be solved with no working system reported. In this thesis, a novel gait representation, the Gait Flow Image (GFI), is proposed to extract more discriminative information from a gait sequence. GFI extracts the relative motion of body parts in different directions in separate motion descriptors. Compared to the existing model-free gait representations, GFI is more discriminative and robust to changes in covariate conditions. In this thesis, gait recognition approaches are evaluated without the assumption on cooperative subjects, i.e. both the gallery and the probe sets consist of gait sequences under different and unknown covariate conditions. The results indicate that the performance of the existing approaches drops drastically under this more realistic set-up. It is argued that selecting the gait features which are invariant to changes in covariate conditions is the key to developing a gait recognition system without subject cooperation. To this end, the Gait Entropy Image (GEnI) is proposed to perform automatic feature selection on each pair of gallery and probe gait sequences. Moreover, an Adaptive Component and Discriminant Analysis is formulated which seamlessly integrates the feature selection method with subspace analysis for fast and robust recognition. Among various factors that affect the performance of gait recognition, change in viewpoint poses the biggest problem and is treated separately. A novel approach to address this problem is proposed in this thesis by using Gait Flow Image in a cross view gait recognition framework with the view angle of a probe gait sequence unknown. A Gaussian Process classification technique is formulated to estimate the view angle of each probe gait sequence. To measure the similarity of gait sequences across view angles, the correlation of gait sequences from different views is modelled using Canonical Correlation Analysis and the correlation strength is used as a similarity measure. This differs from existing approaches, which reconstruct gait features in different views through 2D view transformation or 3D calibration. Without explicit reconstruction, the proposed method can cope with feature mis-match across view and is more robust against feature noise

On Reducing the Effect of Covariate Factors in Gait Recognition: a Classifier Ensemble Method

Robust human gait recognition is challenging because of the presence of covariate factors such as carrying condition, clothing, walking surface, etc. In this paper, we model the effect of covariates as an unknown partial feature corruption problem. Since the locations of corruptions may differ for different query gaits, relevant features may become irrelevant when walking condition changes. In this case, it is difficult to train one fixed classifier that is robust to a large number of different covariates. To tackle this problem, we propose a classifier ensemble method based on the random subspace Method (RSM) and majority voting (MV). Its theoretical basis suggests it is insensitive to locations of corrupted features, and thus can generalize well to a large number of covariates. We also extend this method by proposing two strategies, i.e, local enhancing (LE) and hybrid decision-level fusion (HDF) to suppress the ratio of false votes to true votes (before MV). The performance of our approach is competitive against the most challenging covariates like clothing, walking surface, and elapsed time. We evaluate our method on the USF dataset and OU-ISIR-B dataset, and it has much higher performance than other state-of-the-art algorithms

Review of Person Re-identification Techniques

Person re-identification across different surveillance cameras with disjoint fields of view has become one of the most interesting and challenging subjects in the area of intelligent video surveillance. Although several methods have been developed and proposed, certain limitations and unresolved issues remain. In all of the existing re-identification approaches, feature vectors are extracted from segmented still images or video frames. Different similarity or dissimilarity measures have been applied to these vectors. Some methods have used simple constant metrics, whereas others have utilised models to obtain optimised metrics. Some have created models based on local colour or texture information, and others have built models based on the gait of people. In general, the main objective of all these approaches is to achieve a higher-accuracy rate and lowercomputational costs. This study summarises several developments in recent literature and discusses the various available methods used in person re-identification. Specifically, their advantages and disadvantages are mentioned and compared.Comment: Published 201

Extending quality and covariate analyses for gait biometrics

Recognising humans by the way they walk has attracted a significant interest in recent years due to its potential use in a number of applications such as automated visual surveillance. Technologies utilising gait biometrics have the potential to provide safer society and improve quality of life. However, automated gait recognition is a very challenging research problem and some fundamental issues remain unsolved.At the moment, gait recognition performs well only when samples acquired in similar conditions are matched. An operational automated gait recognition system does not yet exist. The primary aim of the research presented in this thesis is to understand the main challenges associated with deployment of gait recognition and to propose novel solutions to some of the most fundamental issues. There has been lack of understanding of the effect of some subject dependent covariates on gait recognition performance. We have proposed a novel dataset that allows analyses of various covariates in a principled manner. The results of the database evaluation revealed that elapsed time does not affect recognition in the short to medium term, contrary to what other studies have concluded. The analyses show how other factors related to the subject affect recognition performance.Only few gait recognition approaches have been validated in real world conditions. We have collected a new dataset at two realistic locations. Using the database we have shown that there are many environment related factors that can affect performance. The quality of silhouettes has been identified as one of the most important issues for translating gait recognition research to the ‘real-world’. The existing quality algorithms proved insufficient and therefore we extended quality metrics and proposed new ways of improving signature quality and therefore performance. A new fully working automated system has been implemented.Experiments using the system in ‘real-world’ conditions have revealed additional challenges not present when analysing datasets of fixed size. In conclusion, the research has investigated many of the factors that affect current gait recognition algorithms and has presented novel approaches of dealing with some of the most important issues related to translating gait recognition to real-world environments