— As an extension of our previous work on estimating fingertip forces by imaging the fingernail [13], the dynamic features of the coloration response of different parts of the fingernail and surrounding skin to different force levels are studied. The effect of the cardiovascular state on measurable coloration is also characterized. The accuracy of normal force estimated by generalized least squares is presented. A time compensation method for fast force estimation is presented, based on a knowledge of the time constants from the dynamic response of individual fingernail regions.
Yu Sun, John M. Hollerbach, Stephen A. Mascaro