Abstract
Human-robot interaction (HRI) is a field of study that defines the relationship between humans and robot. In robot-assisted mental healthcare, there is still a lack in the methodology especially in evaluating the outcome. In this study, PARO; a robot in the shape of a cute baby seal is introduced as an adjunct therapy tool for six rehabilitation patients with post-stroke depression. Currently, the therapy outcome is measured using psychological tools. When a robot is introduced, a new measurement tool is needed to analyse the patients' response. Thus, this study constructs a tool using OpenCV-Python to detect the number of smiles when each patient interact with PARO. Smile is an indicator of positive emotion and that PARO helps to uplift patient's mood. The results were then compared with psychological evaluations. Both tools show congruent results. The number of smiles increased when patients were holding PARO and PARO helped all patients to manage their psychological distress. This indicates that smile detection is an effective supporting tool to indicate respond in human-robot interaction.