An active imaging digital image correlation method for deformation measurement insensitive to ambient light

Varying ambient light may cause serious decorrelation effect in the images recorded using an ordinary optical imaging device, which prevent digital image correlation (DIC) from out-of-laboratory use. In this paper, we describe an easy-to-implement yet effective monochromatic light illuminated active imaging DIC method for obtaining high-quality images suitable for high fidelity deformation measurement. Experiments reveal that the active imaging DIC method is able to provide reliable and accurate measurements even though the ambient light has been seriously changed. The active imaging DIC method is promising for developing flexible and robust in situ deformation measurement systems for use in both laboratory and non-laboratory environment, and should therefore have more potential engineering applications.

► An active imaging DIC method insensitive to ambient light is proposed.
► The effect of variations in ambient light on recorded digital images is minimized.
► Accurate deformation measurement in non-laboratory environment is thus achievable.
► The proposed method should have more practical engineering applications.