Image Analysis of Metallic Ropes for the Measurement of the Lay Length

The lay length of metallic wire ropes is an important dimensional quantity whose analysis is useful to highlight rope deformations due to distributed damages. The paper describes a measurement system based on a camera, which is employed to acquire images of hauling ropes, and on an image and signal processing algorithm that extracts the rope contour and measures the distance among rope strands. A mathematical model of the rope contour has been derived and it has been employed to test the proposed algorithm with simulated data. The simulation results have been also employed to set the view-angle of the vision system. Preliminary tests have been carried out on an aerial cableway with a general purpose camera in order to test the feasibility of the proposed measurement system.