The aim of this project is to develop a real-time human-machine interaction system that can measure mental workload and stress based on hemodynamic activities of the brain and facial expression using two non-invasive techniques. These techniques are functional near infrared spectroscopy (fNIRS) and a depth camera. fNIRS is an effective tool for brain functional studies, especially for the observation of mental changes through different workload levels. A depth camera is utilised for the task of localising human faces in 3D and recognising facial expressions. We aim at developing a non-invasive and an adaptive aiding system that can provide suitable support interventions depending on the changing cognitive experience of the operators.