Effects of cultural characteristics on building an emotion classifier through facial expression analysis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Facial expressions are an important demonstration of humanity's humors and emotions. Algorithms capable of recognizing facial expressions and associating them with emotions were developed and employed to compare the expressions that different cultural groups use to show their emotions. Static pictures of predominantly occidental and oriental subjects from public datasets were used to train machine learning algorithms, whereas local binary patterns, histogram of oriented gradients (HOGs), and Gabor filters were employed to describe the facial expressions for six different basic emotions. The most consistent combination, formed by the association of HOG filter and support vector machines, was then used to classify the other cultural group: there was a strong drop in accuracy, meaning that the subtle differences of facial expressions of each culture affected the classifier performance. Finally, a classifier was trained with images from both occidental and oriental subjects and its accuracy was higher on multicultural data, evidencing the need of a multicultural training set to build an efficient classifier. (C) 2015 SPIE and IS&TFacial expressions are an important demonstration of humanity's humors and emotions. Algorithms capable of recognizing facial expressions and associating them with emotions were developed and employed to compare the expressions that different cultural gro24219FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2011/22749-8, 2014/04020-9]CNPq [307113/2012-4]2011/22749-8; 2014/04020-9307113/2012-

Improved facial expression recognition via uni-hyperplane classification

Large margin learning approaches, such as support vector machines (SVM), have been successfully applied to numerous classification tasks, especially for automatic facial expression recognition. The risk of such approaches however, is their sensitivity to large margin losses due to the influence from noisy training examples and outliers which is a common problem in the area of affective computing (i.e., manual coding at the frame level is tedious so coarse labels are normally assigned). In this paper, we leverage the relaxation of the parallel-hyperplanes constraint and propose the use of modified correlation filters (MCF). The MCF is similar in spirit to SVMs and correlation filters, but with the key difference of optimizing only a single hyperplane. We demonstrate the superiority of MCF over current techniques on a battery of experiments

Low-resolution facial expression recognition: A filter learning perspective

Abstract(#br)Automatic facial expression recognition has attracted increasing attention for a variety of applications. However, the problem of low-resolution generally causes the performance degradation of facial expression recognition methods under real-life environments. In this paper, we propose to perform low-resolution facial expression recognition from the filter learning perspective. More specifically, a novel image filter based subspace learning (IFSL) method is developed to derive an effective facial image representation. The proposed IFSL method mainly includes three steps: Firstly, we embed the image filter learning into the optimization process of linear discriminant analysis (LDA). By optimizing the cost function of LDA, a set of discriminative image filters (DIFs) corresponding to different facial expressions is learned. Secondly, the images filtered by the learned DIFs are added together to generate the combined images. Finally, a regression learning technique is leveraged for subspace learning, where an expression-aware transformation matrix is obtained using the combined images. Based on the transformation matrix, IFSL effectively removes irrelevant information while preserving useful information in the facial images. Experimental results on several facial expression datasets, including CK+, MMI, JAFFE, SFEW and RAF-DB, show the superior performance of the proposed IFSL method for low-resolution facial expression recognition, compared with several state-of-the-art methods