Facial expression recognition of a speaker using front-view face judgment, vowel judgment, and thermal image processing

For facial expression recognition, we selected three images: (i) just before speaking, (ii) speaking the first vowel, and (iii) speaking the last vowel in an utterance. In this study, as a pre-processing module, we added a judgment function to distinguish a front-view face for facial expression recognition. A frame of the front-view face in a dynamic image is selected by estimating the face direction. The judgment function measures four feature parameters using thermal image processing, and selects the thermal images that have all the values of the feature parameters within limited ranges which were decided on the basis of training thermal images of front-view faces. As an initial investigation, we adopted the utterance of the Japanese name “Taro,” which is semantically neutral. The mean judgment accuracy of the front-view face was 99.5% for six subjects who changed their face direction freely. Using the proposed method, the facial expressions of six subjects were distinguishable with 84.0% accuracy when they exhibited one of the intentional facial expressions of “angry,” “happy,” “neutral,” “sad,” and “surprised.” We expect the proposed method to be applicable for recognizing facial expressions in daily conversation.     

Facial expression recognition of a speaker using vowel judgment and thermal image processing

We have previously developed a method for the recognition of the facial expression of a speaker. For facial expression recognition, we previously selected three images: (i) just before speaking, (ii) speaking the first vowel, and (iii) speaking the last vowel in an utterance. By using the speech recognition system named Julius, thermal static images are saved at the timed positions of just before speaking, and when just speaking the phonemes of the first and last vowels. To implement our method, we recorded three subjects who spoke 25 Japanese first names which provided all combinations of the first and last vowels. These recordings were used to prepare first the training data and then the test data. Julius sometimes makes a mistake in recognizing the first and/or last vowel (s). For example, /a/ for the first vowel is sometimes misrecognized as /i/. In the training data, we corrected this misrecognition. However, the correction cannot be carried out in the test data. In the implementation of our method, the facial expressions of the three subjects were distinguished with a mean accuracy of 79.8% when they exhibited one of the intentional facial expressions of “angry,” “happy,” “neutral,” “sad,” and “surprised.” The mean accuracy of the speech recognition of vowels by Julius was 84.1%.     

Robust facial expression recognition of a speaker using thermal image processing and updating of fundamental training data

We previously developed a method for the facial expression recognition of a speaker. For facial expression recognition, we selected three static images at the timing positions of just before speaking and while speaking the phonemes of the first and last vowels. Then, only the static image of the front-view face was used for facial expression recognition. However, frequent updates of the training data were time-consuming. To reduce the time for updates, we found that the classifications of “neutral”, “happy”, and “others” were efficient and accurate for facial expression recognition. Using the proposed method with updated training data of “happy” and “neutral” after an interval such as approximately three and a half years, the facial expressions of two subjects were discriminable with 87.0 % accuracy for the facial expressions of “happy”, “neutral”, and “others” when exhibiting the intentional facial expressions of “angry”, “happy”, “neutral”, “sad”, and “surprised”.     

Facial expression recognition of a speaker using thermal image processing and reject criteria in feature vector space

In our previously developed method for the facial expression recognition of a speaker, the positions of feature vectors in the feature vector space in image processing were generated with imperfections. The imperfections, which caused misrecognition of the facial expression, tended to be far from the center of gravity of the class to which the feature vectors belonged. In the present study, to omit the feature vectors generated with imperfections, a method using reject criteria in the feature vector space was applied to facial expression recognition. Using the proposed method, the facial expressions of two subjects were discriminable with 86.8 % accuracy for the three facial expressions of “happy”, “neutral”, and “others” when they exhibited one of the five intentional facial expressions of “angry”, “happy”, “neutral”, “sad”, and “surprised”, whereas these expressions were discriminable with 78.0 % accuracy by the conventional method. Moreover, the proposed method effectively judged whether the training data were acceptable for facial expression recognition at the moment.     

A methodology for rapid illumination-invariant face recognition using image processing filters

Achieving illumination invariance in the presence of large pose changes remains one of the most challenging aspects of automatic face recognition from low resolution imagery. In this paper, we propose a novel recognition methodology for their robust and efficient matching. The framework is based on outputs of simple image processing filters that compete with unprocessed greyscale input to yield a single matching score between two individuals. Specifically, we show how the discrepancy of the illumination conditions between query input and training (gallery) data set can be estimated implicitly and used to weight the contributions of the two competing representations. The weighting parameters are representation-specific (i.e. filter-specific), but not gallery-specific. Thus, the computationally demanding, learning stage of our algorithm is offline-based and needs to be performed only once, making the added online overhead minimal. Finally, we describe an extensive empirical evaluation of the proposed method in both a video and still image-based setup performed on five databases, totalling 333 individuals, over 1660 video sequences and 650 still images, containing extreme variation in illumination, pose and head motion. On this challenging data set our algorithm consistently demonstrated a dramatic performance improvement over traditional filtering approaches. We demonstrate a reduction of 50–75% in recognition error rates, the best performing method-filter combination correctly recognizing 97% of the individuals.     

The facial expression recognition technology under image processing and neural network

The Journal of Supercomputing - A facial expression recognition (FER) algorithm is built on the advanced convolutional neural network (CNN) to improve the current FER algorithms’ recognition...     

A novel fuzzy facial expression recognition system based on facial feature extraction from color face images

Emotion recognition plays an effective and important role in Human-Computer Interaction (HCI). Recently, various approaches to emotion recognition have been proposed in the literature, but they do not provide a powerful approach to recognize emotions from Partially Occluded Facial Images.In this paper, we propose a new method for Emotion Recognition from Facial Expression using Fuzzy Inference System (FIS). This novel method is even able to recognize emotions from Partially Occluded Facial Images. Moreover, this research describes new algorithms for facial feature extraction that demonstrate satisfactory performance and precision. In addition, one of the main factors that have an important influence on the final precision of fuzzy inference systems is the membership function parameters. Therefore, we use a Genetic Algorithm for parameter-tuning of the membership functions. Experimental results report an average precision rate of 93.96% for Emotion Recognition of six basic emotions, which is so promising.     

Hybrid-boost learning for multi-pose face detection and facial expression recognition

This paper proposes a hybrid-boost learning algorithm for multi-pose face detection and facial expression recognition. To speed-up the detection process, the system searches the entire frame for the potential face regions by using skin color detection and segmentation. Then it scans the skin color segments of the image and applies the weak classifiers along with the strong classifier for face detection and expression classification. This system detects human face in different scales, various poses, different expressions, partial-occlusion, and defocus. Our major contribution is proposing the weak hybrid classifiers selection based on the Harr-like (local) features and Gabor (global) features. The multi-pose face detection algorithm can also be modified for facial expression recognition. The experimental results show that our face detection system and facial expression recognition system have better performance than the other classifiers.     

Dynamics of facial expression: recognition of facial actions and their temporal segments from face profile image sequences.

Automatic analysis of human facial expression is a challenging problem with many applications. Most of the existing automated systems for facial expression analysis attempt to recognize a few prototypic emotional expressions, such as anger and happiness. Instead of representing another approach to machine analysis of prototypic facial expressions of emotion, the method presented in this paper attempts to handle a large range of human facial behavior by recognizing facial muscle actions that produce expressions. Virtually all of the existing vision systems for facial muscle action detection deal only with frontal-view face images and cannot handle temporal dynamics of facial actions. In this paper, we present a system for automatic recognition of facial action units (AUs) and their temporal models from long, profile-view face image sequences. We exploit particle filtering to track 15 facial points in an input face-profile sequence, and we introduce facial-action-dynamics recognition from continuous video input using temporal rules. The algorithm performs both automatic segmentation of an input video into facial expressions pictured and recognition of temporal segments (i.e., onset, apex, offset) of 27 AUs occurring alone or in a combination in the input face-profile video. A recognition rate of 87% is achieved.     

Speech synthesis of emotions using vowel features of a speaker

Recently, methods for adding emotion to synthetic speech have received considerable attention in the field of speech synthesis research. We previously proposed a case-based method for generating emotional synthetic speech by exploiting the characteristics of the maximum amplitude and the utterance time of vowels, and the fundamental frequency of emotional speech. In the present study, we propose a method in which our reported method is further improved by controlling the fundamental frequency of emotional synthetic speech. As an initial investigation, we adopted the utterance of a Japanese name that is semantically neutral. By using the proposed method, emotional synthetic speech made from the emotional speech of one male subject was discriminable with a mean accuracy of 83.9 % when 18 subjects listened to the emotional synthetic utterances of “angry,” “happy,” “neutral,” “sad,” or “surprised” when the utterance was the Japanese name “Taro,” or “Hiroko.” Further adjustment of fundamental frequency in the proposed method made a much clearer impression on the subjects for emotional synthetic speech.     

Fusion of visible and thermal images for facial expression recognition

Most present research into facial expression recognition focuses on the visible spectrum, which is sensitive to illumination change. In this paper, we focus on integrating thermal infrared data with visible spectrum images for spontaneous facial expression recognition. First, the active appearance model AAM parameters and three defined head motion features are extracted from visible spectrum images, and several thermal statistical features are extracted from infrared (IR) images. Second, feature selection is performed using the F-test statistic. Third, Bayesian networks BNs and support vector machines SVMs are proposed for both decision-level and feature-level fusion. Experiments on the natural visible and infrared facial expression (NVIE) spontaneous database show the effectiveness of the proposed methods, and demonstrate thermal IR images’ supplementary role for visible facial expression recognition.     

Three-dimensional face recognition using shapes of facial curves

We study shapes of facial surfaces for the purpose of face recognition. The main idea is to 1) represent surfaces by unions of level curves, called facial curves, of the depth function and 2) compare shapes of surfaces implicitly using shapes of facial curves. The latter is performed using a differential geometric approach that computes geodesic lengths between closed curves on a shape manifold. These ideas are demonstrated using a nearest-neighbor classifier on two 3D face databases: Florida State University and Notre Dame, highlighting a good recognition performance     

利用图像处理技术解决人脸识别中小样本问题

通过应用PCA及2DPCA算法进行人脸识别,得到了在取不同特征值门限情况下的特征提取维数和识别率,给出了以上两种算法最优特征提取向量的维数和最大特征值门限,并在此基础上应用双线性差值图像旋转处理技术,增加了同一个人较少训练样本情况下的训练样本数量,提高了识别率,从一定程度上解决了小样本问题。如果能从小样本图像中生成出一些新的预测信息,例如,增加同一个训练样本的不同的表情,或改变样本表情的深度,实验的效果可能更加明显。     

A face detection and recognition system in color image series

A human face detection and recognition system for color image series is presented in this paper. The system is composed of two subsystems: human face detection subsystem and human face recognition subsystem. The face detection subsystem includes two modules: face finding and face verification. The human face finding module determines the face regions of a number of subjects from color image series using skin color analysis and motion analysis. The human face verification module is developed to verify the detected human faces by judging of eclipse and support vector machine (SVM), and precisely localize human faces by locating eyes and mouths based on Generalized Symmetry Transform. The features characterizing the relation between face patterns can be extracted and selected by Principal Component Analysis. Using these selected features to train multiple SVMs, we can finally classify human faces. Moreover, in these modules, several simple and complex methods are used to reduce the searching space. So the system can work at a high speed and high detection and recognition rate. Human face detection accuracy of the system is 97.2% under controllable lightning condition. Human face recognition accuracy of the system for 70 persons is 96.5% (with 20 eigenvectors) and 98.3% (with 30 eigenvectors).     

A novel deep network architecture for reconstructing RGB facial images from thermal for face recognition

Multimedia Tools and Applications - This work proposes a fully convolutional network architecture for RGB face image generation from a given input thermal face image to be applied in face...     

Application of two-dimensional canonical correlation analysis for face image processing and recognition

Paper presents the method of two-dimensional canonical correlation analysis (2DCCA) applied to image processing and biometrics. Method is based on representing the image as the sets of its rows (r) and columns (c) and implementation of CCA using these sets (for this reason we named the method as CCArc). CCArc features simple implementation and lower complexity than other known approaches. In applications to biometrics CCArc is suitable to solving the problems when dimension of images (dimension of feature space) is greater than number of images, i.e. when Small Sample Size (SSS) problem exists.     

A human-machine cooperative system for generating sign language animation using thermal image processing,a fuzzy algorithm,and simulated annealing

We propose a method for a sign language animation by skin region detection applied to an infrared thermal image. In a system incorporating the proposed method, a 3D CG model corresponding to a person’s characteristic posture while using sign language is generated automatically by pattern recognition of the thermal image, and then a person’s hand in the CG model is set. The hand part is made manually beforehand. If necessary, the model can be replaced manually by a more appropriate model corresponding to training key frames, and/or the same generated model can be refined manually. In our experiments, three hearing-impaired people, who were experienced in using sign language, recognized the Japanese sign language gestures of 70 words expressed as animations with 94.3% accuracy. We further improved the system by correcting the position and direction of the hand of the automatically generated model through the use of a fuzzy algorithm and simulated annealing.