Comparison of different optical techniques to measure skin vibrations

We test different possible setups to measure skin vibrations in the abdominal region which could, in the future, enable quick and comfortable monitoring of aortic aneurysms in the abdominal region. For this study, a simple mechanical model is used that simulates the human tissue and a large blood vessel, the aorta. The model consists of a plastic box filled with a gelatin as used for ballistic experiments. A rubber hose goes straight through the gel block and, with a pump that is connected to the hose, one can create a pulsatile flow of water through the flexible hose leading to traveling waves along the artificial vessel. Surface vibrations on the gelatin block are then measured using a Laser-Doppler vibrometer (LDV), a commercial 3D DIC system and a simple camera setup with only one camera and an additional mirror for 3D capabilities. While the LDV offers the best signal quality, it can only measure one point simultaneously. We discuss implications how this will influence the possible data analyses compared to more noisy, but full-field measurements provided by the camera-based systems.