g microphones that create less internal noise will mean major enhancements to speech intelligibility in noisy envi- ronments, Miles says. He notes that the improvements will be accomplished by research in three interrelated areas: directional microphones, optical elec- tronic sensors, and signal processing. Along with Miles, the project's principal investigator, researchers Douglas Jones of the University of Illinois, an expert in signal processing algorithms, and Levent Degertekin of the Georgia Insti- tute of Technology, an expert in optical sensors, are also participating in this research. It is hoped that optical sensors will replace and improve on the variable capacitors used in traditional hearing-aid technology. By "reading out" sound waves hitting the microphone's diaphragm through signals created by changes in light rather than in electronic voltage, much thinner and more sensitive diaphragms can be used. "This will remove some of the key design constraints that have limited the development of small microphones," says Miles. "It should permit a revolution in microphone designs and enable the achievement of much greater sensitivity and lower noise." The signal processing algorithms will allow for the fine-tuning and cus- tomization of hearing aid sensitivity and will reduce unwanted sounds beyond what is possible with existing hearing aid technology. Ultimately, the signal processing could be tuned based on various criteria, including directionality, frequency, or volume of sounds, Miles says. Initially, the researchers will focus on directionality, since most hearing-aid users want to hear the speaker or sound source they are facing more than other ambient room noise. Ultimately, Miles' work will affect any application in which a miniaturized microphone and signal processing technology could improve a product's utility and performance. Besides the development of next-generation hearing aids, other envisioned applications include security devices, mobile phones, and teleconferencing equipment. THE CRITICA