Técnicas de vis o computacional aplicadas no processo de calibra o de instrumentos de medi o com display numérico digital sem interface de comunica o de dados

The process of calibrating instruments that do not have built-in data communication interfaces is very time-consuming and may be subject to human error since it involves many data readings and annotations by the technician who performs the task. In this context, automated systems play an important role since they can provide higher accuracy, repeatability, cost reduction and standardization of results. This paper explores the use of computer vision techniques in automating the process of calibrating measurement instruments with numeric digital displays that do not have data communication interfaces. Using a USB camera, the image of the instrument display is acquired; and, after its analysis, the digits are recognized and the corresponding values stored in a file to be used in issuing calibration certificates. For thistask, three different approaches were described and evaluated. Experimentalresults showed a high reliability in two of them, suggesting that both can be applied in the automation of the calibration process.