Time Axis Analysis of Gravity Distorted Speech.
J Calvin Hunter · Masters Thesis · 1981
Abstract : An algorithm to determine energy shift along the time axis was applied to digitized speech data, which had been recorded at six different gravity levels. The analog speech was recorded during the centrifuge tests at the Air Force Medical Research Lab, Wright-Patterson AFB, Ohio. The data was then digitized, Fourier Transformed, high frequency preemphasized, channel compressed, and energy-normalized. The processed files were checked for time duration of each word in both the time and frequency domain. Large time-duration differences--up to 200 msecs--were recorded; but there was no statistical mapping pattern of distortion versus gravity level. Time distortion of the speech energy within a given gravity level was as significant as the distortion between gravity levels. The results indicate that no additional time warping considerations will need to be made within the speech recognition algorithms to compensate for gravity fluctuations. (Author)