Sensors 2013, 13(12), 16682-16713; doi:10.3390/s131216682
Hierarchical Recognition Scheme for Human Facial Expression Recognition Systems
1
UC Lab, Department of Computer Engineering, Kyung Hee University, Yongin-Si 446-701, Korea
2
Division of Information and Computer Engineering, Ajou University, Suwon 443-749, Korea
*
Author to whom correspondence should be addressed.
Received: 28 October 2013 / Revised: 30 November 2013 / Accepted: 2 December 2013 / Published: 5 December 2013
(This article belongs to the Section Physical Sensors)
Abstract
Over the last decade, human facial expressions recognition (FER) has emerged as an important research area. Several factors make FER a challenging research problem. These include varying light conditions in training and test images; need for automatic and accurate face detection before feature extraction; and high similarity among different expressions that makes it difficult to distinguish these expressions with a high accuracy. This work implements a hierarchical linear discriminant analysis-based facial expressions recognition (HL-FER) system to tackle these problems. Unlike the previous systems, the HL-FER uses a pre-processing step to eliminate light effects, incorporates a new automatic face detection scheme, employs methods to extract both global and local features, and utilizes a HL-FER to overcome the problem of high similarity among different expressions. Unlike most of the previous works that were evaluated using a single dataset, the performance of the HL-FER is assessed using three publicly available datasets under three different experimental settings: n-fold cross validation based on subjects for each dataset separately; n-fold cross validation rule based on datasets; and, finally, a last set of experiments to assess the effectiveness of each module of the HL-FER separately. Weighted average recognition accuracy of 98.7% across three different datasets, using three classifiers, indicates the success of employing the HL-FER for human FER. View Full-TextKeywords:
face detection; GHE; facial expressions; PCA; ICA; LDA; HMMs
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MDPI and ACS Style
Siddiqi, M.H.; Lee, S.; Lee, Y.-K.; Khan, A.M.; Truc, P.T.H. Hierarchical Recognition Scheme for Human Facial Expression Recognition Systems. Sensors 2013, 13, 16682-16713.