Imaging the Finger Force Direction

This paper presents a method of imaging the coloration pattern in the fingernail and surrounding skin to infer fingertip force direction during planar contact. Nail images from 7 subjects were registered to reference images with RANSAC and then warped to an atlas with elastic registration. Recognition of fingertip force direction, based on linear discriminant analysis, shows that there are common color pattern features in the fingernail and surrounding skin for different subjects. Based on the common features, the overall recognition accuracy is 92%