Analysis of industry-related flows by optical coherence tomography: A review

Optical Coherence Tomography (OCT) is a light-based imaging method capable of simultaneously capturing the internal structure and motion (1D, 2D or 3D) of various opaque and turbid materials with a micron-level spatial resolution. Depending on the OCT technology, axial scanning rates can vary in a range of tens to hundreds of kHz. The actual imaging depth significantly depends on the optical properties of the material and can vary from micrometers to a few millimeters. From the viewpoint of industrial applications, OCT technology is very appealing. Due to its resolution, speed, and ability to deal with opaque materials, it fills an apparent gap in available measurement methods. Nonetheless, OCT has not to date seen widespread growth in the industrial field. This has been at least partly due to a lack of commercial devices compact and flexible enough to adapt to industrial needs. The recent emergence of more generic commercial OCT devices has considerably lowered the threshold for adapting the technique. The utilization of OCT for structural analysis, also outside the medical field, has been thoroughly discussed in scientific literature. Therefore, in this paper, we will mainly concentrate on applications of OCT that also utilize its capability of performing velocity measurements. The emphasis will be on industrially motivated problems such as rheology, microfluidics, fouling and turbulence.