Coins are a primary need of human life. They are used in everyone's daily routine, like banks, transport, market and these spare changes also has various other uses than realization traded in for cash similar to measurement purpose, in games (toss), in organizations for research point, etc. So, it holds a vast significance that coins can be detected with high accuracy. Main aim of a coin recognition system is to classify high volumes of coins with high accuracy within short time duration. In this paper we discussed a various techniques of coin recognition systems in respective terms of their accuracy. Also focused on different coin recognition approaches have been planned by different researchers based on image recognition method. Categorization is based on images from both sides as well as a radius of the coin.