Shadow moire surface topology inspection with calibration samples

摘要

Apparatus and a method for inspecting a topology of a surface (2) of a structural member (1) are provided. The degree to which a known type of stress has been applied to the member may be ascertained using a Moiré grid (8). The method involves providing a range of calibration samples of structurally equivalent members, the samples each having been subject to the known type of stress to a differing respective degree. Measurements taken using the apparatus and method of the invention are then compared with measurements taken from a calibration sample to determine the amount of stress which has been applied.