Hamdi Dibeklioglu

Hamdi Dibeklioglu
Bilkent University · Department of Computer Engineering

PhD

About

57
Publications
30,160
Reads
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2,243
Citations
Citations since 2017
17 Research Items
1463 Citations
2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250
Additional affiliations
September 2017 - present
Bilkent University
Position
  • Professor (Assistant)
July 2013 - September 2017
Delft University of Technology
Position
  • PostDoc Position
March 2009 - July 2013
University of Amsterdam
Position
  • PhD Student
Education
March 2009 - September 2014
University of Amsterdam
Field of study
  • Intelligent Systems, Computer Vision
September 2006 - July 2008
Bogazici University
Field of study
  • Computer Engineering
September 2002 - June 2006
Yeditepe University
Field of study
  • Computer Engineering

Publications

Publications (57)
Article
Multimodal interfaces offer ever-changing tasks and challenges for designers to accommodate newer technologies, and as these technologies become more accessible, newer application scenarios emerge. Prototype development and user evaluation are important steps in the creation of solutions to these challenges. Furthermore, playful interactions and ga...
Article
Personality analysis is an important area of research in several fields, including psychology, psychiatry, and neuroscience. With the recent dramatic improvements in machine learning, it has also become a popular research area in computer science. While the current computational methods are able to interpret behavioral cues (e.g., facial expression...
Article
Introduction: The most prominent risk factor of Alzheimer's disease (AD) is aging. Aging also influences the physical appearance. Our clinical experience suggests that patients with AD may appear younger than their actual age. Based on this empirical observation, we set forth to test the hypothesis with human and computer-based estimation systems....
Article
Full-text available
Interactive reinforcement learning provides a way for agents to learn to solve tasks from evaluative feedback provided by a human user. Previous research showed that humans give copious feedback early in training but very sparsely thereafter. In this article, we investigate the potential of agent learning from trainers’ facial expressions via inter...
Preprint
Interactive reinforcement learning provides a way for agents to learn to solve tasks from evaluative feedback provided by a human user. Previous research showed that humans give copious feedback early in training but very sparsely thereafter. In this article, we investigate the potential of agent learning from trainers' facial expressions via inter...
Technical Report
Full-text available
Analysis of personality traits is a common study of interest for various fields including psychology, psychiatry, and neuroscience. In the recent years, with the improvements in computing power, it has also become a popular area of study in computer science. Recent machine learning and computer vision models are able to interpret behavioral cues, s...
Preprint
Lies and deception are common phenomena in society, both in our private and professional lives. However, humans are notoriously bad at accurate deception detection. Based on the literature, human accuracy of distinguishing between lies and truthful statements is 54% on average, in other words it is slightly better than a random guess. While people...
Article
Full-text available
Analysis of kinship from facial images or videos is an important problem. Prior machine learning and computer vision studies approach kinship analysis as a verification or recognition task. In this paper, for the first time in the literature, we propose a kinship synthesis framework, which generates smile and disgust videos of (probable) children f...
Article
The level of taste liking is an important measure for a number of applications such as the prediction of long-term consumer acceptance for different food and beverage products. Based on the fact that facial expressions are spontaneous, instant and heterogeneous sources of information, this paper aims to automatically estimate the level of taste lik...
Article
Full-text available
We present a new model for multivariate time-series classification, called the hidden-unit logistic model (HULM), that uses binary stochastic hidden units to model latent structure in the data. The hidden units are connected in a chain structure that models temporal dependencies in the data. Compared with the prior models for time-series classifica...
Article
Full-text available
The main challenges of age estimation from facial expression videos lie not only in the modeling of the static facial appearance, but also in the capturing of the temporal facial dynamics. Traditional techniques to this problem focus on constructing handcrafted features to explore the discriminative information contained in facial appearance and dy...
Article
Depression is one of the most common psychiatric disorders worldwide, with over 350 million people affected. Current methods to screen for and assess depression depend almost entirely on clinical interviews and self-report scales. While useful, such measures lack objective, systematic, and efficient ways of incorporating behavioral observations tha...
Conference Paper
Full-text available
The TAMER framework provides a way for agents to learn to solve tasks using human-generated rewards. Previous research showed that humans give copious feedback early in training but very sparsely thereafter and that an agent's competitive feedback — informing the trainer about its performance relative to other trainers — can greatly affect the trai...
Conference Paper
Full-text available
Current methods for depression assessment depend almost entirely on clinical interview or self-report ratings. Such measures lack systematic and efficient ways of incorporating behavioral observations that are strong indicators of psychological disorder. We compared a clinical interview of depression severity with automatic measurement in 48 partic...
Article
Full-text available
Current methods for depression assessment depend almost entirely on clinical interview or self-report ratings. Such measures lack systematic and efficient ways of incorporating behavioral observations that are strong indicators of psychological disorder. We compared a clinical interview of depression severity with automatic measurement in 48 partic...
Article
Full-text available
Estimating the age of a human from the captured images of his or her face is a challenging problem. In general, existing approaches to this problem use appearance features only. In this paper, we show that in addition to appearance information, facial dynamics can be leveraged in age estimation. We propose a method to extract and use dynamic featur...
Article
Full-text available
Automatic distinction between genuine (spontaneous) and posed expressions is important for visual analysis of social signals. In this paper, we describe an informative set of features for the analysis of face dynamics, and propose a completely automatic system to distinguish between genuine and posed enjoyment smiles. Our system incorporates facial...
Chapter
Facial dynamics contain idiosyncratic information that can help appearance-based systems in a number of tasks. This paper summarizes our research on using facial dynamics as a soft biometric, in establishing the age and kinship similarity, as well as for assessing expression spontaneity. Our findings suggest that high-resolution and high-frequency...
Conference Paper
Full-text available
Computer based methods for facial age estimation can be improved by incorporating experimental findings from human psychophysics. Moreover, the latter can be used in creating systems that are not necessarily more accurate in age estimation, but strongly resemble human age estimations. In this paper we investigate the perceptual hypothesis that cont...
Conference Paper
Full-text available
Image-based kinship recognition is an important problem in the reconstruction and analysis of social networks. Prior studies on image-based kinship recognition have focused solely on pair wise kinship verification, i.e. on the question of whether or not two people are kin. Such approaches fail to exploit the fact that many real-world photographs co...
Conference Paper
Full-text available
Most modern object trackers combine a motion prior with sliding-window detection, using binary classifiers that predict the presence of the target object based on histogram features. Although the accuracy of such trackers is generally very good, they are often impractical because of their high computational requirements. To resolve this problem, th...
Conference Paper
Full-text available
Model-free tracking aims identify the location of particular objects or object parts in each frame of a video based on a single positive example. In our work, we (1) develop online-learning algorithms for part-based models that facilitate the use of these models in model-free tracking in order to improve robustness to partial occlusions, and (2) de...
Article
Full-text available
The aim of this study was to characterize the biochemical profiles of the virgin olive oils produced in various districts of Aegean and South East Anatolia regions of Turkey over two growing seasons (2001–2002). The olive oils were extracted by classic hydraulic pressing, three phase continuous system, Abencor oil method at laboratory scale, and fo...
Conference Paper
Automatic kinship verification methods are conventionally based on facial appearance. In contrast to all published material, in this paper, we explore the use of facial expression dynamics and spatio-temporal features for kinship verification from smile videos. It is shown that the combined use of dynamic and spatio-temporal features extracted from...
Conference Paper
Full-text available
Kinship verification from facial appearance is a difficult problem. This paper explores the possibility of employing facial expression dynamics in this problem. By using features that describe facial dynamics and spatio-temporal appearance over smile expressions, we show that it is possible to improve the state of the art in this problem, and verif...
Conference Paper
Age estimation from face images traditionally focuses on appearance features. In this paper, we evaluate a number of recently proposed spatio-temporal features for the problem of age estimation from face videos. It is shown that temporal features based on movement dynamics of facial landmarks during a smile expression can improve age estimation ove...
Conference Paper
Full-text available
Estimation of a person's age from the facial image has many applications, ranging from biometrics and access control to cosmetics and entertainment. Many image-based methods have been proposed for this problem. In this paper, we propose a method for the use of dynamic features in age estimation, and show that 1) the temporal dynamics of facial feat...
Conference Paper
This paper deals with the design and adaptation of the response displayed by an interactive photo frame application. The user of the system is monitored with a camera, and based on the user's facial expressions and activity levels, the system selects its response, and in time, fine-tunes it to the particular user. A user study is conducted showing...
Article
Full-text available
Many facial-analysis approaches rely on robust and accurate automatic facial landmarking to correctly function. In this paper, we describe a statistical method for automatic facial-landmark localization. Our landmarking relies on a parsimonious mixture model of Gabor wavelet features, computed in coarse-to-fine fashion and complemented with a shape...
Conference Paper
Full-text available
Smiling is an indispensable element of nonverbal social interaction. Besides, automatic distinction between spontaneous and posed expressions is important for visual analysis of social signals. Therefore, in this paper, we propose a method to distinguish between spontaneous and posed enjoyment smiles by using the dynamics of eyelid, cheek, and lip...
Article
Full-text available
This paper describes an affect-responsive interac-tive photo-frame application that offers its user a different experience with every use. It relies on visual analysis of activity levels and facial expressions of its users to select responses from a database of short video segments. This ever-growing database is automatically prepared by an of-flin...
Conference Paper
Full-text available
Automatic detection of affective states from facial images and videos is a very important application in social signal process- ing. In this study we focus on the expression of happiness, and propose a physiologically inspired approach for detecting whether a smile is spontaneously produced or not. We use distance-based and angular features that ch...
Conference Paper
Full-text available
Automatic detection of spontaneous versus posed facial expressions received a lot of attention in recent years. However, almost all published work in this area use complex facial features or multiple modalities, such as head pose and body movements with facial features. Besides, the results of these studies are not given on public databases. In thi...
Conference Paper
In this paper we develop a fully automatic emotional expression recognition system. We propose improvements on a recent facial landmark localization method. This method is then used to bootstrap a Bezier volume tracker for tracking facial features in video. The motion of the facial features is used in classifying the expression of the face. We pres...
Article
Full-text available
Olives were collected from various districts of Turkey (North and South Aegean sub-region, Bursa-Akhisar, South East Anatolia region) harvested over seven (2001–2007) seasons. The aim of this study was to characterize the chemical profiles of the oils derived from single variety Turkish olives including Ayvalik, Memecik, Gemlik, Erkence, Nizip Yagl...
Conference Paper
Full-text available
In this work, we propose a fully automatic pose and expression invariant part-based D face recognition system. The proposed system is based on pose correction and curvature-based nose segmentation. Since the nose is the most stable part of the face, it is largely invariant under expressions. For this reason, we have concentrated on locating the nos...
Article
Full-text available
The commercially produced multicellular microalgae, Spirulina platensis, is widely consumed by humans in the Aegean area of Turkey as a food addi-tive or a whole food. The fatty acid profiles of six commercial tablets pro-duced from S. platensis in Turkey and one from China were determined. The samples contained 33.68-66.75% saturated fatty acids (...
Conference Paper
This paper contrasts two approaches to facial landmarking in 3D. The first approach is statistical in nature, and is based on modeling the shape of each feature with Gaussian mixtures. The advantage of this approach is the uniform treatment of landmarks. The second approach is a hybrid method to find the nose tip, which does not require learning, a...
Article
Full-text available
The fatty acid (FA) profiles of edible muscle of selected commercially important freshwater and marine fish species from Turkey were investigated. The fatty acid compositions of freshwater fish species were 23.00–29.60% saturated (SFA), 25.70–36.50% monounsaturated (MUFAs), and 26.59–31.92% polyunsaturated acids (PUFAs), whereas the fatty acid comp...
Conference Paper
Full-text available
Automatic localization of 3D facial features is important for face recognition, tracking, modeling and expression analysis. Methods developed for 2D images were shown to have problems working across databases acquired with different illumination conditions. Expression variations, pose variations and occlusions also hamper accurate detection of land...
Conference Paper
Full-text available
This paper presents an evaluation of several 3D face recognizers on the Bosphorus database which was gathered for studies on expression and pose invariant face analysis. We provide identification results of three 3D face recognition algorithms, namely generic face template based ICP approach, one-to-all ICP approach, and depth image-based Principal...
Conference Paper
This paper exhibits the performance drop in 3D face recognition in the presence of expression and proposes a new 3D face registration and recognition method based on facial regions. For fast alignment, a registration method based on iterative closest point (ICP) algorithm is used which employs average regional models (ARMs). Similarity scores obtai...
Conference Paper
Full-text available
A new 3D face database that includes a rich set of expressions, systematic variation of poses and different types of occlusions is presented in this paper. This database is unique from three aspects: i) the facial expressions are composed of judiciously selected subset of Action Units as well as the six basic emotions, and many actors/actresses are...
Conference Paper
Full-text available
zetçe Bu bildiride, ifadenin varlığında sabit kayıtlamaya dayalı 3B yüz tanıma yöntemlerinin iyi başarım sağlamadığı gösterilmiş olup, başarım arttırımı için bölgesel kayıtlama ve tanıma yapılması önerilmiştir. Hızlı hizalama amaçlı, ortalama bölge modelleriyle yinelemeli en yakın nokta (ICP) algoritmasına dayalı kayıtlama yöntemi kullanılmıştır. B...
Chapter
Full-text available
This project aims at developing a biometric authentication system exploiting new features extracted by analysing the dynamic nature of various modalities, including motion analysis during ordinary tasks performed in front of a computer, analysis of speech, continous face and facial movement analysis, and even patterns for grasping objects. We test...
Conference Paper
Interactive multimedia such as computer simulations and animations received increased attention over the years as supplementary teaching tools and have now become integral components of most engineering and science curriculums. We believe one way to boost the utility of such simulations and animations is to make them easier to use. In this paper, w...
Conference Paper
In this study we designed a system that can track 3D motion and generate new pieces of motion, using a stereo camera setup. A dataset from some expressions of Turkish sign language is built using markers. In order to find the center of the markers and track their coordinates the correspondence problem had to be solved. Results of newly proposed mar...
Conference Paper
Full-text available
Interactive multimedia such as computer simulations and animations received increased attention over the years as supplementary teaching tools and have now become integral components of most engineering and science curriculums. We believe one way to boost the utility of such simulations and animations is to make them easier to use. In this paper, w...

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