Relative and absolute coordinates measurement by phase-stepping laser interferometry

Relative and absolute coordinates measurements of real objects by phase-stepping laser interferometry are presented. The method proposed is suitable for remote nondestructive testing and accurate measurement of real object such as machine's parts, modules, constructions, as well as archaeological monuments and in biomedical investigations for spinal deformations measurements of human body, etc. Theoretical analysis for calculation of the coordinates from the measured phase difference in illumination of the objects with different phase-shifted interference patterns as well as uncertainty of the measurements are proposed. A good agreement with experimentally obtained results is achieved.