Adherence detector using canny edge detector

An adherence detector is a device for detecting the proximity of a stock rail and a tongue rail (less than 5 mm in the case of NS-AM type). The existing adherence detectors such as Paulve or proximity sensors can mechanically or electrically detect whether they are in close contact or not. However, the contact level cannot be detected, and field inspection is required twice a week. In this paper, we propose a new method to measure the contact level of an adherence detector in mm by applying a Canny Edge Detector and present the measurement results. The proposed scheme provides a warning signal in real time when the closeness is under 3 to 4 mm, and indicates a mismatch when the closeness is more than 4 mm. Experimental results show that the error of measurement of closeness between stock rail and tongue rail is within ±0.56 mm and device can provide accurate measurement value for system requirements.