I. Introduction
Facial expressions are some of the best ways a person communicates with the outside world. It reflects the thoughts, beliefs and the emotions experienced by a person; thereby showcasing their mental state. FER can be defined as the process of detecting and recognizing a person's emotions with the help of their facial expressions [1] and hence can be employed for non-verbal communication [2]. With the recent advancements in humanoid robots, FER is utilized for multiple applications [3] [4]. These include lie detection, understanding certain mental disorders, analyzing customer reactions and many more.