High-Precision Vision Sensor Method for Dam Surface Displacement Measurement

Dam surface displacement measurement can monitor the safety of dam operation and provide early warning for dam accidents. This paper proposes a method for measuring the displacement of the dam surface based on double vision sensors. Mathematical morphology is combined with the Roberts edge detection operator to complete the sub-pixel extraction of the marker edge. The method makes the edge of the marker in the image smoother compared with the Zernike moment sub-pixel edge detection algorithm. The edge gray center of gravity method is proposed to realize the positioning of the marker, which improves the precision of the vision measurement method. Additionally, this paper proposes the design of a test system and describes the experiments conducted in this study. The results revealed that the proposed method can achieve millimeter-level measurement accuracy and has the advantages of simple operation, short measurement period, online monitoring, and low cost, which satisfies the requirements for measuring the dam surface displacement.