1. Accurate collection of facial features. Illumination, occlusions, head rotation, etc. may seriously affect accuracy, but this is exactly our main focus right now. We are at the very start of the process, yet early experiments and some recent papers show that it should be doable.
2. Correlation between real and detected emotional state. At the moment we concentrate on the 6 basic emotions and don't detect less common expressions like depression with smiling face. This topic is definitely interesting and I'm pretty much sure it's possible to implement given enough training data, but right now we try to concentrate on different things.