Dictionary learning has been applied to face recognition and gets good results. However few works applied dictionary learning in facial expression recognition. This paper investigates the application of K-SVD in facial expression recognition. Since K-SVD focuses on reconstruction and lacks discriminant capability. It has similar classification performance with image pixel values. To address this problem, this paper proposes a Combined Dictionary Scheme, which uses combination of separate dictionaries. This yields better performance than the original single dictionary scheme in terms of both recognition rate and computation complexity.
 Z. Y. Zhang, X. M. Mu and L. Gao, “Recognizing Facial Expressions Based on Gabor Filter Selection,” Proceedings of 2011 4th International Congress on Image and Signal Processing (CISP). IEEE, 2011, Vol. 3, pp. 1544–1548.
 Michal Aharon, Michael Elad, and Alfred Bruckstein, “K-SVD: An Algorithm for Designing Overcomplete Dictionaries for Sparse Representation,” IEEE Transactions on Signal Processing, Vol. 54, No. 4, 2006, pp. 4311–4321.doi:10.1109/TSP.2006.881199
 Julien Mairal and Francis Batch et al., “Discriminative Learned Dictionaries for Local Image Analysis,” Proceedings of 2008 IEEE Conference on Computer Visionand Pattern Recognition (CVPR), IEEE, 2008, pp. 1–8.
 Z. L. Jiang, L. Zhe and L. S. Davis, “Learning a Discriminative Dictionary for Sparse Coding via Label Consistent K-SVD,” Proceedings of 2011 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), IEEE, 2011, pp. 1697-1704.
 S. Dubuisson, F. Davoine and M. Masson, “A Solution for Facial Expression Representation and Recognition,” Signal Processing: Image Communication, Vol. 17, No. 9, 2002, pp. 657–673. doi:10.1016/S0923-5965(02)00076-0
 N. Peter Belhumeur, P. Joao Hespanha and David J. Kriegman, “Eigenfaces vs. Fisherfaces: Recognition Using Class Specific Linear Projection,” IEEE Transactions on Pattern Analysis and Machine Intelligence, Vol. 19, No. 7, 1997, pp. 711-720. doi:10.1109/34.598228
 F. Y. Shih, C. F. Chuang and Patrick, S. P. Wang, “Performance Comparisons of Facial Expression Recognition in JAFFE Database,” International Journal of Pattern Recognition and Artificial Intelligence, Vol. 22, Vol. 3, 2008, pp. 445-459.doi:10.1142/S0218001408006284