Robust speckle metrology for stress measurements outside the lab

Optical techniques are usually related to laboratory rooms, which are places equipped with temperature, humidity and vibration control. These techniques are very suitable for fast measurements due to their non-contact nature and full-field capability. Among them, optical methods based on the speckle phenomenon have had a great development during the last two decades because of the development of digital image processing, cameras, computers, lasers and optical components. Speckle techniques have the advantages cited for optical methods. Additionally, they are adequate for the evaluation of real components without further preparation of the surface and without high time consuming to be analyzed. This paper supplies tools, tips and reference parameters to develop interferometers based on the speckle phenomenon to be used outside the laboratory room Finally, applications outside the lab for the measurement of mechanical and residual stresses are presented. These examples show the high potential of speckle metrology as an auxiliary tool for structure integrity assessment.