Cutting tools are one of the widely used tools in the manufacturing sector. It is an important problem to monitor the condition of tools in order to decide whether the tool is worn or not. There have been various methods making use of the measurement of current, force, vibration, power or acoustic emission for this purpose. Tool monitoring is determined using image processing techniques, novel to this paper. The sharpness of the cutting edge can be determined after each drilling operation. A canny edge detector is utilized to obtain the edge information of the cutting tool. Afterwards, wear condition of the tool is decided using a decision metric that is constructed to determine the sharpness of cutting edges. © 2005 IEEE.