Modeling Head-Related Transfer Functions Based on Pinna Anthropometry

The use of Head-Related Transfer Functions (HRTFs) in creating 3D sounds is gaining wide acceptance in multimedia applications. This paper presents a new method of modeling HRTFs based on the shape and size of the outer ear. Using signal processing tools, such as Prony’s signal modeling method, an appropriate set of time delays and a resonant frequency were used to approximate the measured HeadRelated Impulse Responses (HRIRs). HRIRs represent HRTFs in time domain. Statistical analysis was used to find out empirical equations describing how the reflections and resonances are determined by the shape and size of the pinna features obtained from 3D images of 15 experimental subjects modeled in the project. These equations were used to yield “Model HRTFs” that can create elevation effects. Listening tests conducted on 10 subjects showed that these model HRTFs were 5% more effective than generic HRTFs in the frontal plane. This model is a simple, yet effective method of creating customizable HRTFs. It reduces the computational and storage demands, while preserving a sufficient number of perceptually relevant spectral cues.