LOMo: Latent Ordinal Model for Facial Analysis in Videos

We study the problem of facial analysis in videos. Our first contribution is a novel weakly supervised learning method that models the video event (pain, expression etc.) as a sequence of automatically mined, discriminative sub-events (eg. neutral face, raising brows, contracting lips). The proposed model is inspired by the recent works on Multiple Instance Learning and latent SVM/HCRF- it extends such frameworks to model the ordinal or temporal aspect in the videos, approximately. We show consistent improvements over relevant competitive baselines on four challenging and publicly available video based facial analysis datasets for prediction of expression, clinical pain and intent in dyadic conversations. In combination with complimentary features, we report state-of-the-art results on these datasets.