Model-based Crack Width Estimation using Rectangle Transform

The automated image-based robust estimation of crack widths in concrete structures forms a significant component in the automation of structural health monitoring. The proposed method, called rectangle transform, uses the gray-scale profile extracted perpendicularly to the direction of crack propagation. Based on the concept of an idealized profile, it transforms the empirical profile into an equal-area rectangle from which the width is inferred. On the available dataset and compared to two other approaches, it shows at least par performance for widths larger two pixels and distinctly better performance on widths smaller equal two pixels. Moreover, it is more robust towards blurred input.