An Average of the Human Ear Canal: Recovering Acoustical Properties via Shape Analysis
This work addresses the lack of detailed anatomical data for the bony part of the ear canal, which is important for applications like hearing aid design, but it is incremental as it builds on existing image registration methods.
The study tackled the problem of modeling the entire human ear canal, including the bony part, by creating an average shape from MRI scans using image registration, and demonstrated that this representation has acoustical properties nearly identical to a real ear.
Humans are highly dependent on the ability to process audio in order to interact through conversation and navigate from sound. For this, the shape of the ear acts as a mechanical audio filter. The anatomy of the outer human ear canal to approximately 15-20 mm beyond the Tragus is well described because of its importance for customized hearing aid production. This is however not the case for the part of the ear canal that is embedded in the skull, until the typanic membrane. Due to the sensitivity of the outer ear, this part, referred to as the bony part, has only been described in a few population studies and only ex-vivo. We present a study of the entire ear canal including the bony part and the tympanic membrane. We form an average ear canal from a number of MRI scans using standard image registration methods. We show that the obtained representation is realistic in the sense that it has acoustical properties almost identical to a real ear.