The Automatic Detection of Chronic Pain-Related Expression: Requirements, Challenges and the Multimodal EmoPain Dataset. - Min S. H. Aung; Sebastian Kaltwang; Bernardino Romera-Paredes; Brais Martínez; Aneesha Singh; Matteo Cella; Michel F. Valstar; Hongying Meng; Andrew Kemp; Moshen Shafizadeh; Aaron C. Elkins; Natalie Kanakam; et al. (IEEE Trans. Affect. Comput., 2016)