Snake based automatic tracing of vocal-fold motion from high-speed digital images

High-speed digital imaging (HSDI) of the larynx provides important information on the vocal fold vibrations that are closely associated with voice condition. We present an active contour (snake)-based algorithm for the automatic delineation of the glottis within image sequences captured from an HSDI system. The algorithm has three steps: first, a rough segmentation is performed by global thresholding, and followed by the detection of an ellipse-shaped region that approximates the glottal geometry, secondly, parameters of the ellipse are estimated using the principal component analysis (PCA) method and thirdly, the snake-method is applied using the estimated ellipse as an initial contour. The performance of the proposed approach is demonstrated through the use of clinical samples of the HSDI recordings obtained from subjects having both normal and pathological voice conditions. Finally the proposed method is compared with existing snake-based methods in terms of efficiency and segmentation accuracy.