Vision Based Measurement applied to Industrial Instrumentation

Abstract

Machine Vision applied in the area of Instrumentation and Measurement is known as Vision Based Measurement. Its application in industry is steadily increasing principally due to the recent developments in computer hardware and computer vision algorithms. In this article we discuss the possibilities of combining industrial local sensors with a camera and a computer, thus obtaining a new type of transmitter based in Machine Vision. The possibility of transforming visual information into digital data, which can be readily available in an industrial network, opens a variety of new applications. As a case study, we propose and implement a Vision Based Measurement system capable of measuring and transmitting the value indicated by a pointer-scale indicator. To verify the applicability of the proposed transmitter the following results are presented: (i) the associated standard uncertainty is evaluated; (ii) the influence of the image size in the transmitter’s uncertainty is investigated; (iii) the proposed transmitter is compared with a regular electronic transmitter and, (iv) its processing time is evaluated. The results obtained in laboratory are promising and indicate that the use of the proposed Machine Vision system in industry is a real possibility.