Mapping of Three-Dimensional (3D) Structure of Ear Canal and Auricle

Abstract

We demonstrate mapping of three-dimensional (3D) structure to determine details of surface profiles of the ear canal and auricle. In order to measure the surface profile of the ear canal, we developed an optical scanner for inner surface profile measurement, and clarified the optical properties of the cone beam. When the standard deviation of 7-mm ring gauges made of high-density polyethylene was measured, the error of measurement was ±0.05mm. Then, we compared the three-dimensional mapping of the ear canal between our method and a contact three-dimensional surface profile measurement method. The difference between the two methods was －0.15mm, and the full width at half maximum was ±0.58mm. Moreover, we achieved three-dimensional mapping for not only the ear canal, but also the auricle using an articulated arm based on kinematics. Our research provides three-dimensional mapping to determine surface profiles from the eardrum to auricle, without using impression materials.