Vision system for monitoring the production of corrugated cardboard

In this paper a vision system for the control quality in a factory of corrugated cardboard is described. The problem under study is the automatic detection and monitoring of the sheets of cardboard constituting a unit of sale. A precise measurement of the number of sheets is a difficult task, since, during the process, some sheets must be discarded, because of their inferior quality, or because they have been damaged during the transport. Usually, the number of the sheets is estimated from the ratio between the weight of the unit and the nominal weight of a single sheet. Since the weight of a sheet is uncertain, an estimation based on the weight ratio is poor and its reliability is very low. A different solution is proposed in this paper: it estimates the number of the sheets via a suitable vision system. It offers a very high precision (the middle error is smaller of 2%) and it has the advantages to avoid invasive interactions with the process of production and to be a low cost solution.