The industry of piston segment is one of the most important within the automotive components parts sector. The piston segment machining process consists of several stages during which the product control plays an essential role in order to prevent rejected components. The several operations required to obtain the final machining form are closely related and their feasibility is dependent on each other. The human intervention between operations leads to mistakes during the operations and therefore to defective components. In particular, the positioning of the segments before the final grinding operation is of extreme importance for the final result. In order to overcome the human errors in the different stages and in particular in a pile the in the segment positioning, it is envisaged to develop an On-line vision system computer supported which will indentify the right position before the last machining step. In addition, the final control of the segments (measurement system) will be integrated in the overall system. This global system will allow to decrease the rejected rate and therefore incease produtivity, as well as to assure the product quality and reduce the production costs. The automation associated to this system will promote the reduction of human errors in the production line.