Imaging fingertip skin deformation in response to scanned edges

Touch is a complex sensory system involving a high density of mechanoreceptors in the fingertips, which provide crucial information about the environment, such as an object's geometry, texture, and mechanical properties, as well as the nature and magnitude of interactions, offering continuous feedback during grasping and dexterous manipulation. In particular, the activity of tactile afferents has been linked to local skin deformations in the finger pad. This Master's thesis project was conducted at the Institute of Neuroscience (IoNS) of the Université catholique de Louvain, where previous studies employed a robotic platform to investigate local tangential strains of the fingertip during controlled interactions with flat transparent surfaces, enabling the acquisition of images of the skin during contact. This work extended the research to non-flat stimuli, utilizing the same apparatus. First, small bump and hole geometries were economically and reproducibly manufactured on a flat transparent resin plate, replacing the flat glass surfaces. Second, the interaction of the skin with these profiles was imaged at high spatiotemporal resolution through the plate, allowing for the extraction and temporal tracking of skin features to quantify local skin deformations. The technical challenges introduced by the employment of non-flat stimuli were addressed through the image processing techniques proposed in this study, which allowed for the successful detection and identification of consistent and recurrent deformation patterns associated with the specific profiles analyzed.