Sound source localization of human ear in a planner surface using ...

Abstract

The human auditory system is a collection of technical theories and mathematical equations in the context of human sound source localization process. Also, according to the developed human ear models, under the disciplines related to engineering and biomedical science, the electrical ear model can further be used in deriving the biological human auditory system mathematically. In this research, the outer ear, middle ear, inner ear related to both ears and the brain are considered as the total human auditory system. In developing the mathematical model of human auditory system, electrical model of human ear is considered and using MATLAB powersim library mathematical model is developed. Experiment -1 is conducted to collect raw data for the proposed human auditory model. In the experiment, a dummy head with two condenser microphones to record the left and right ear sound signals is selected and placed in middle of circles having 1m, 2m and 3m radius. Then 1 kHz and 5 kHz distinct sounds are played at 24 different locations and incident sound signals as a stereo signal is recorded using desktop computer. Experiment -2 is conducted to investigate the individual ability to predict the direction of a sound source. Ten numbers of samples of young adults from the age group of 20 to 30 years are taken into the experiment and their responses for localization cues are recorded. The experiment is also conducted for different sound source locations such as 1m, 2m and 3m and different source frequencies of 1 kHz and 5 kHz. With the raw data collected under experiment-1, sound signal is processed through each ear of the proposed mathematical model using MATLAB and using Interaural Time Difference (ITD) and interaural Level Difference (ILD), sound source localization is done. In comparison with the actual human sound source localization analyzed under the experiment 2, the proposed model is verified. The results show that the proposed mathematical biological auditory system obeys the characteristics of real human auditory system at frequencies less than 1500 Hz, while the sound source localization algorithm is a combination of interaural time and level differences. On the other hand, at higher frequencies, the model deviates from the real human auditory system characteristics, The proposed mathematical model of human auditory system follows the real human auditory system behavior at frequencies less than 1500Hz, with the combination of ILD and ITD sound localization algorithms. Also, at higher frequencies, the model deviates from the real human auditory system and the actual sound localization algorithm at higher frequencies is yet to be investigated.