Geng, L., W. Li, J. Xi, and Y. Liu. “Pointer Temperature and Humidity Meter Detection Based on Machine Vision”. American Scientific Research Journal for Engineering, Technology, and Sciences, vol. 52, no. 1, Feb. 2019, pp. 162-75, https://www.asrjetsjournal.org/index.php/American_Scientific_Journal/article/view/4654.