Kevin Lenzo
Dept. of Comput. and Inf. Sci., Ohio State Univ., Columbus, OH 43210
Donna Erickson
Ohio State Univ., Columbus, OH 43210
A method for data analysis was developed to aid in processing x-ray pellet traces of articulatory tract motion. Segmentation criteria may be determined by constraints on the first and second derivative, and then selected segments are measured in terms of position, excursion distance, velocity, duration, and curve area measurements computed by Riemann approximation. Measurements currently encompass the segment as a whole, and the initial and final portions with respect to the maximum. An index is assigned to each segment. Parameters allow the user to generate values for only those regions involved in specific analysis tasks, to set the sensitivity of the first and second derivative zero-crossing algorithm, and to choose the right, left or center portion of the continuous regions that satisfies the derivative constraints often bracketing a true zero-crossing in order to more precisely define start and end measurements points. For instance, some mandible motion segments have smooth beginnings and endings, but others show edge perturbation, e.g., the word ``five'' sometimes shows a slope or plateau before the jaw movement drops into the vocalic valley. Some possible applications for this approach to measuring articulatory and other motion data are discussed. [This work has been supported in part by Shannon Award (NIDCD #1 R55 DC00015-01A1) and by a research fund from ATR, International, both given to O. Fujimura.]