Optical method for measuring the surface area of a threaded fastener

Quantifying the surface area of a threaded fastener is essential to properly calculating an accurate corrosion rate. The method proposed here determines the surface area by acquiring a digital image of the fasteners and applying specific algorithms to identify key features of the fasteners to extract appropriate dimensions that can be used in analytical expressions to determine the total surface area of a threaded fastener. This method was then validated by correctly calculating the surface area of a #10 wood screw. By applying this method to historic corrosion data, the true corrosion rates were calculated for comparison with other studies.3