1.0 Introduction The feeling and its understanding are very important in human behavior because feeling is the driving force of our behaviors and daily activities and gives meaning to our life experiences. Without feeling, our works are like a series of preset orders which are done with no mood. Feeling gives not only color and odor to our behaviors but also greatly controls our behavior. In fact, by creating a sense of experience, we became interested to it or getting away from it or we may even have the other different behaviors. On one hand, we see that people who have more positive feelings are of higher quality in life and even their longevity and life expectancy are higher. On the other hand, there are many diseases that disturb the individual′s daily activity by impairment of emotions and affect their lives. These diseases are not rare but they are very common, for example, the well–known disease of our time is depression that is very common among different communities and gripped many people. The issue of feeling and the need to study it are discussable from various aspects. Each of which can create sufficient motivation for these studies. Perhaps the simplest reasons that come to the mind are enjoying of life and having good and positive feelings. On the other hand, the rapid growth of technology causes the entry of robots to the market that are fast, smart and automatic. Nevertheless, it is better that these senseless robots armed with emotions in order to know and understand their user′s emotions and respond to them. Studies in this field can lead to more enjoyable humancomputer interaction and boost computer games industry or create humanoid friend and companion. The issue of feeling identification is applicable in medicine, entertainment, human computer interface (HCI), companion, coach and generally social activities. The goal is to succeed in pattern recognition and quantification of emotions such as anger, love and so on in order to use it for treatment of mental illnesses or increase health status.