Customizable facial expression recognition using non-negative matrix factorization

We proposed a facial motion tracking and expression recognition system based on video data. By a 3D deformable facial model, the online statistical model (OSM) and cylinder head model (CHM) were combined to track 3D facial motion in the framework of particle filtering. For facial expression recognition, a fast and efficient algorithm and a robust and precise algorithm were developed. With the first, facial animation and facial expression were retrieved sequentially. After that facial animation was obtained, facial expression was recognized by static facial expression knowledge learned from anatomical analysis. With the second, facial animation and facial expression were simultaneously retrieved to increase the reliability and robustness with noisy input data. Facial expression was recognized by fusing static and dynamic facial expression knowledge, the latter of which was learned by training a multi-class expressional Markov process using a video database. The experiments showed that facial motion tracking by OSM+CHM is more pose robust than that by OSM, and the facial expression score of the robust and precise algorithm is higher than those of other state-of-the-art facial expression recognition methods.

Most facial expression recognition (FER) systems used facial expression data created during a short period of time and this data is used for learning/training of FER systems. There are many facial expression patterns (i.e. a particular expression can be represented in many different patterns) which cannot be generated and used as learning/training data in a short time. Therefore, in order to maintain its high accuracy and robustness for a long time of a facial expression recognition system, the classifier should be evolved adaptively over time and space. We proposed a facial expression recognition system that has the aptitude of incrementally learning and thus can learn all possible patterns of expressions that may be generated in feature. After extraction of region of interest (face), the system extracts Speeded-Up Robust Features (SURF). A novel SURF descriptor template based nearest neighbor classifier is proposed for classification. This classifier is used as base/weak classifier for incremental learning algorithm Learn++. A vast range of experimentation is performed on five different databases that demonstrate the incremental learning capability of the proposed system. The experiments using the incrementally learning classification demonstrate promising results.

Facial expressions convey nonverbal cues which play an important role in interpersonal relations, and are widely used in behavior interpretation of emotions, cognitive science, and social interactions. In this paper we analyze different ways of representing geometric feature and present a fully automatic facial expression recognition (FER) system using salient geometric features. In geometric feature-based FER approach, the first important step is to initialize and track dense set of facial points as the expression evolves over time in consecutive frames. In the proposed system, facial points are initialized using elastic bunch graph matching (EBGM) algorithm and tracking is performed using Kanade-Lucas-Tomaci (KLT) tracker. We extract geometric features from point, line and triangle composed of tracking results of facial points. The most discriminative line and triangle features are extracted using feature selective multi-class AdaBoost with the help of extreme learning machine (ELM) classification. Finally the geometric features for FER are extracted from the boosted line, and triangles composed of facial points. The recognition accuracy using features from point, line and triangle are analyzed independently. The performance of the proposed FER system is evaluated on three different data sets: namely CK+, MMI and MUG facial expression data sets.

Facial expressions can be seen as a form of non-verbal communication as well as a primary means of conveying social information among humans.Automatic facial expression recognition (FER) can be applied to a wide range of scenarios in human-computer interaction, facial animation, entertainment, and psychology studies. For feature representation in a FER system, various texture descriptors have been employed to derive an effective solution for this system. However, these individual texture descriptor-based FER systems have often failed to achieve effective performance in the recognition of facial expressions. In this sense, it is necessary to further improve the general performance of a facial expression recognition system, evaluating different feature representations. In this paper, a novel local descriptor for a facial expression recognition system is proposed, designated the level of difference descriptor (LOD). The main goal is to use this descriptor as a supplement to state-of-the-art local descriptors to further improve the performance of a FER system in terms of classification accuracy. Furthermore, the fusion of various texture features for devising a robust feature representation for multi-view facial expression recognition is presented.

An automatic system for facial expression recognition should be able to recognize on-line multiple facial expressions (i.e. “emotional segments”) without interruption. The current paper proposes a new method for the automatic segmentation of “emotional segments” and the dynamic recognition of the corresponding facial expressions in video sequences. First, a new spatial filtering method based on Log-Normal filters is introduced for the analysis of the whole face towards the automatic segmentation of the “emotional segments”. Secondly, a similar filtering-based method is applied to the automatic and precise segmentation of the transient facial features (such as nasal root wrinkles and nasolabial furrows) and the estimation of their orientation. Finally, a dynamic and progressive fusion process of the permanent and transient facial feature deformations is made inside each “emotional segment” for a temporal recognition of the corresponding facial expression. When tested for automatic detection of “emotional segment” in 96 sequences from the MMI and Hammal-Caplier facial expression databases, the proposed method achieved an accuracy of 89%. Tested on 1655 images the automatic detection of transient features achieved a mean precision of 70 % with an error of 2.5 for the estimation of the corresponding orientation. Finally compared to the original model for static facial expression classification, the introduction of transient features and the temporal information increases the precision of the classification of facial expression by 12% and compare favorably to human observers’ performances.

A human face has a distinct and unique characteristics which make it play a very critical role in recognizing facial expression in a “facial expression recognition system.” Identifying or as we say it detection of expressions plays a big and significant role in a facial expression recognition system. If we talk about a human being it becomes an easy task recognize expression in any particular image sequence, but at the same time if we talk about fully automated systems not many are currently available or capable to do so. The field of facial expression recognition do have many different applications and its importance, it might be used to have an interaction between a human being and a computer, here a user, without using his hands, can give commands or instruct to the computer system with the help of facial expression recognition system. Quite a few options are available to identify a face in an image in an efficient and accurate manner, although similar cannot be said for features detection in a video sequence frame. Most systems are still dependent on manual operations for same. Here in this paper we have emphasizes on color normalization and facial feature extraction which uses LBP (Local Binary Pattern) as an effective feature detection approach, where the existing algorithms have been modified to improve the facial expression recognition accuracy. The recognition accuracy on the Indian database is observe to be 94.7\%.

Facial expressions recognition and synthesis are important research fields to study how human beings reflect to environments in affective computing. With the rapid development of mathematical theory on multivariate statistics and multi-media technology especially image processing, facial expressions recognition researchers have achieved many useful results. Recently studies show that approaches to facial modeling and expressions recognition and synthesis analysis could be adapted to control security or even real-time health monitoring in the real world. Similarity, how to achieve facial expressions recognition and synthesis for independent-free mechanism is a central design in general. Based on the cognitive analysis of independent user's affective facial recognition researches we proposed an emotions composition model to dope out what are the user's new affective facial expressions. At this point, principal component, cluster and discriminate analysis were applied to show and verify independent user's affective expressions can be composited for synthesis by basic facial expressions such as happy, neutral and unhappy. Experiments were conducted to prove our models to be very significant.

Human neuroimaging and behavioural studies suggest that somatomotor ‘mirroring’ of seen facial expressions may support their recognition. Here we show that viewing specific facial expressions triggers the representation corresponding to that expression in the observer’s brain. Twelve healthy female volunteers underwent two separate fMRI sessions: one where they observed and another where they displayed three types of facial expressions (joy, anger and disgust). Pattern classifier based on Bayesian logistic regression was trained to classify facial expressions (i) within modality (trained and tested with data recorded while observing or displaying expressions) and (ii) between modalities (trained with data recorded while displaying expressions and tested with data recorded while observing the expressions). Cross-modal classification was performed in two ways: with and without functional realignment of the data across observing/displaying conditions. All expressions could be accurately classified within and also across modalities. Brain regions contributing most to cross-modal classification accuracy included primary motor and somatosensory cortices. Functional realignment led to only minor increases in cross-modal classification accuracy for most of the examined ROIs. Substantial improvement was observed in the occipito-ventral components of the core system for facial expression recognition. Altogether these results support the embodied emotion recognition model and show that expression-specific somatomotor neural signatures could support facial expression recognition.

Recently, there has been a huge demand for assistive technology for industrial, commercial, automobile, and societal applications. In some of these applications, there is a requirement of an efficient and accurate system for automatic facial expression recognition (FER). Therefore, FER has gained enormous interest among computer vision researchers. Although there has been a plethora of work available in the literature, an automatic FER system has not yet reached the desired level of robustness and performance. In most of these works, there has been the dominance of appearance-based methods primarily consisting of local binary pattern (LBP), local directional pattern (LDP), local ternary pattern (LTP), gradient local ternary pattern (GLTP), and improved local ternary pattern (IGLTP). Keeping in view the popularity of appearance-based methods, in this paper, we have proposed an appearance-based descriptor called Improved Adaptive Local Ternary Pattern (IALTP) for automatic FER. This new descriptor is an improved version of ALTP, which has been proved to be effective in face recognition. We have investigated ALTP in more details and have proposed some improvements like the use of uniform patterns and dimensionality reduction via principal component analysis (PCA). The reduced features are then classified using kernel extreme learning machine (K-ELM) classifier. In order to validate the performance of the proposed method, experiments have been conducted on three different FER datasets using well-known evaluation measures such as accuracy, precision, recall, and F1-Score. The proposed approach has also been compared with some of the state-of-the-art works in literature and found to be more accurate and efficient.

Single‐mode sensors suffer from poor robustness and insufficient data features in facial expression recognition, so fusing multi‐sensor signals is the key to improving the accuracy of expression recognition systems. Here, a biocompatible capacitive‐electromyographic dual‐mode sensor (CEDS) is presented, consisting of a capacitive pressure sensing unit and dry electrodes for electrophysiological signal monitoring, assembled in a 3D stacking fashion. A double‐coupled microstructure is prepared and the electrical double‐layer effect is realized by doping ionic liquid, which significantly improves the capacitive performance of the sensor. The application of dry electrodes effectively solves the problems of hydrogel electrodes that are prone to water loss and skin irritation. Besides, the good biocompatibility and antimicrobial properties of CEDS are verified through cytotoxicity and bacteriostatic tests. Based on the sensing of a single signal, a fatigue driving monitoring system and a manipulator control system are constructed respectively. By further integrating the capacitive and electrophysiological signal monitoring functions of CEDS, a 1D convolutional neural network‐assisted facial expression recognition system is constructed, which effectively improves the accuracy of expression recognition and demonstrates the great potential of facial expression monitoring systems based on flexible sensor technology in practical applications.

The digital animation process is a complex endeavour requiring professional animators to acquire substantial expertise and technique through years of study and practice. Particularly, facial animation, where virtual humans express specific mental states or emotions with a desire for realism, is further complicated by the “Uncanny Valley” phenomenon. In this context, it is posited that pre-validated facial expressions for certain emotions could serve as references for the novice or inexperienced animators during the facial animation and posing process of their virtual humans using morph targets, also known as blend shapes or shape keys. This research presents a comparative study between two Facial Expression Recognition (FER) systems that employ pre-trained models for facial recognition applied to emotion recognition in virtual humans. Given that these systems were not designed or trained for this particular purpose but for facial recognition in real humans, this study aims to investigate their level of applicability in scenarios where virtual humans are used instead of real humans. This assessment is a critical step towards evaluating the feasibility of integrating FER models as part of a support tool for facial animation and the posing of virtual humans. Through this investigation, this research provides evidence of the reliability of applying the FER library and Deepface systems for emotion recognition in virtual humans, contributing to investigating new ways to enhance the digital animation process and overcoming the inherent complexities of facial animation.

Recently, facial expression recognition has attracted much attention in machine vision research because of its various applications. Accordingly, many facial expression recognition systems have been proposed. However, the majority of existing systems suffer from a critical problem: geometric variability. It directly affects the performance of geometric feature-based facial expression recognition approaches. Furthermore, it is a crucial challenge in appearance feature-based techniques. This variability appears in both neutral faces and facial expressions. Appropriate face geometry normalization can improve the accuracy of each facial expression recognition system. Therefore, this paper proposes different geometric models or shapes for normalization. Face geometry normalization removes geometric variability of facial images and consequently, appearance feature extraction methods can be accurately utilized to represent facial images. Thus, some expression-based geometric models are proposed for facial image normalization. Next, local binary patterns and local phase quantization are used for appearance feature extraction. A combination of an effective geometric normalization with accurate appearance representations results in more than a 4% accuracy improvement compared to several state-of-the-arts in facial expression recognition. Moreover, utilizing the model of facial expressions which have larger mouth and eye region sizes gives higher accuracy due to the importance of these regions in facial expression.

In this paper, Facial Expression Recognition (FER) system, aid in modeling facial expression space for facial expression recognition by facial characteristic points and Gini index. Facial expression information are mostly concentrated on facial expression information regions, so the, eyes, eyebrows, and mouth are extracted from the input image. When a face image is input the feature extraction is performed which help in detecting facial characteristic points. Facial animation parameters are calculated in order to recognize one of the six basic facial expressions. The proposed technique is applied to JAFFE database consisting 30 images, each having six basic facial expression images (neutral, happy, surprise, fear, sad and angry). For certain expressions like, surprise, fear and happy it gives the promising results with best recognition rate, however for expressions like, neutral, sad and angry the recognition rate is lower. The proposed technique is implemented in MATLAB version 7.8.0.347 (R2009a).

In this paper, we propose a novel scheme for automatic recognition of facial expressions captured from both fronto-parallel and non-fronto-parallel cameras i.e., multi-view facial expressions (MVFE). The proposed scheme introduce a Local Saliency-inspired Binary Pattern (LSiBP) feature to recognize MVFE. First view-specific approximated saliency likelihood map (ASLM) is derived during training of our model. ASLM is determined from the 2D structure tensor representation of faces. The distribution of saliency likelihoods of pixels along with pixel intensities are analyzed in extracting LSiBP features from a face. Such LSiBP features are utilized for training and testing of view-specific SVM classifiers. Extensive experiments are performed on datasets of both posed and unconstrained spontaneous expressions of MVFE. Our scheme outperforms state-of-the-arts by at least 1% to recognize MVFE.

These Human facial expressions convey a lot of information visually rather than articulately. Facial expression recognition plays a crucial role in the area of human-machine interaction. Automatic facial expression recognition system has many applications including, but not limited to, human behaviour understanding, detection of mental disorders, and synthetic human expressions. Recognition of facial expression by computer with high recognition rate is still a challenging task. Two popular methods utilized mostly in the literature for the automatic FER systems are based on geometry and appearance. Facial Expression Recognition usually performed in four-stages consisting of pre-processing, face detection, feature extraction, and expression classification. The human face is an important part of an individual’s body and plays an important role in knowing the individual’s mood. The face is where a human expresses all his basic emotions. In the existing system, they examine the mental state manually by assessing them but have many disadvantages like we cannot predict any accurate solutions based on the assessment score because we might be not sure what kind of emotions the human user would be all time. To overcome this problem, a novel system is proposed to suggest an effective solution for predicting the mental state dynamically, we propose a hybrid architecture invoking facial based emotion sequence, PEN test and IQ test. By consistent monitoring of a human’s emotion and subjecting to PEN and IQ tests, the human’s mental state is routed. Combination of the above three techniques provides promising results for mental state and self-control