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Fig. 11. Pictorial concept of application of audio annotation—left: helicopter sensing and transmission; right: sound annotation to the soundscape.
development of a near-field acoustic holography measure- ment and analysis technology. This technology will scan a full scale jet plume and provide the 3-D noise radiation pro- file. Applications include quantifying near-field noise expo- sure for maintenance personnel, identification of noise sources in the plume, and development and validation of jet noise reduction technologies. Another example of an AFRL SBIR contract effort is the development of techniques to capture, analyze, and re-synthesize 3-D soundscapes. The product of this effort will be used in investigating the effects of local soundscape on the community perception of noise from aircraft operations and in the mitigation or reduction of the perceived noise.
Emerging efforts
Future directions involve the integration of auditory tech- nologies with future visual display systems for presenting large amounts of data for rapid and accurate decision making. Spatial auditory displays and enhanced communication will be applied in Unmanned Air Vehicle (UAV) operations and air- borne and ground command and control. Investigation and leveraging of the interactions of cognition with auditory per- ception in decision making will also be addressed. Two focus areas are—(1) audio annotation where advanced audio dis- plays are used for referencing critical events in simulated oper- ational environments, a concept shown in Fig. 11 and (2) net- centric communications where the results of multi-talker speech perception research is exploited to improve the effec- tiveness of communications in a highly integrated multi-chan- nel voice communication network environment. In physical acoustics, AFRL will investigate the interactions, modeling, and validation of weather and terrain with linear and non-lin- ear propagation of directional sources. Additional standards
work will focus on the establishment of new standards for fast Fourier transforms (FFT) analyzers, spatial audiometry, speech level measurement, and the measurement of impulsive noise for hearing damage risk assessment.
Summary
The AFRL acoustics research group is an exciting place to work on cutting edge projects in bioacoustics and physi- cal acoustics with freedom to explore innovative solutions to complex problems. The acoustic research facilities are among the best in the world. The researchers are a group of excellent scientists and engineers developing new technolo- gies protecting and enhancing the performance of military personnel. Many of the AFRL developed technologies have had significant application and use in the civilian sector.
AFRL has been a leader in the development of hearing conservation and hearing protection for over 60 years. AFRL researchers have pioneered the establishment of continuous noise exposure criteria and national and international stan- dards for noise measurement, measurement of hearing pro- tector performance, and speech communication.
Major technology developments and related scientific findings include: passive hearing protector technologies, hearing conservation programs, active noise reduction headsets, broadband sirens, acoustic fatigue, community noise mapping, studies of airbag noise, lateral attenuation of aircraft flyover noise, atmospheric modeling, infrasound, bone conduction, sonic boom measurement, human response to sonic booms, communication earplugs, speech communication in noise, hearing protector measurement standards, active noise reduction earplugs, 3-D audio dis- play technologies, and an auditory artificial horizon for air- craft.AT
28 Acoustics Today, January 2010