Stanowisko do automatycznego odczytu wartości mierzonej miernikiem analogowym

W artykule przedstawiono stanowisko do automatycznego odczytu wartości mierzonej miernikiem analogowym (woltomierz magnetoelektryczny). Do rejestracji obrazu zastosowano standardową kamerę internetową oraz oprogramowanie LabVIEW. Wykorzystano narzędzia z modułu NI Vision Development. Do detekcji wskazówki zastosowano transformatę Hougha. Przedstawiono wyniki badań wpływu parametrów rejestracji i przetwarzania obrazu oraz natężenia oświetlenia na detekcję wskazówki miernika analogowego.

The paper presents an application for automatic reading of the measured value from an analogue meter. The software of the proposed application was developed in the LabVIEW environment using the NI Vision Development. For image acquisition the standard webcam was used (Fig.2). The analogue magneto-electric voltmeter with measuring ranges: 1,5 V; 3 V and 7,5 V was used as a testing instrument. The Hough transform (1) was applied to detection of the analogue meter indicator. Determination of the range of measurements was carried out using patternmatching methods. Fig. 5 presents the algorithm for determining the measuring range and the final value. The influence of illumination on the detection of the analog meter indicator was also examined. The obtained results are shown in Fig. 6. The analysis of the effect of the light intensity was made under artificial lighting. A digital luxmeter LUXMETER L-50 SONOPAN was used in the test procedure. The elaborated application (for the tested range 400-3000 lx) is fully useful for detection of image elements. The results of investigations of the influence of acquisition parameters and parameters of image processing on the detection of the analog meter indicator are included.