D. L. Martinez, O. Rudovic and R. Picard, "Personalized Automatic Estimation of Self-Reported Pain Intensity from Facial Expressions," 2017 IEEE Conference on Computer Vision and Pattern Recognition Workshops (CVPRW), Honolulu, HI, USA, 2017, pp. 2318-2327, doi: 10.1109/CVPRW.2017.286. keywords: {Pain;Estimation;Face;Recurrent neural networks;Hidden Markov models;Image sequences;Reliability},