Vocal folds analysis using global energy tracking

Introduction: Detection and quantification of oscillatory irregularities in laryngeal videostroboscopy can be particularly difficult for the human expert. Accordingly, there is a wide interest in automated methods for recovering the folds' temporal trajectory. Unfortunately, current methods typically provide only crude glottal measurements. Objectives: An automated procedure for consistently tracking the entire vocal folds' boundary in laryngeal stroboscopy videos, even when the glottal opening is closed. Methods: A preprocessing frame-by-frame crude midpoint identification is followed by an active contour evolution to detect the global boundary in each frame independently. A global energy active contour is then jointly defined over the entire video sequence, and the full glottal boundary is detected throughout the video via standard energy minimization. Results: The vocal folds' boundary is accurately tracked in normal and abnormal stroboscopy videos collected in a clinical setting, and that exhibit a varied range of visual characteristics (eg, lighting conditions). A proof-of-concept evaluation based on the analysis of the waveform of the location of points along the boundary separates between a normal and two markedly different abnormal subjects, and automatically provides a hypothesized localization of the abnormality. Conclusion: The first method for automatically tracing the temporal trajectory of all points along the vocal folds' boundary in all frames of a stroboscopy video is presented. The approach opens the door for novel analysis of all regions of the contour, which in turn may lead to automated localization of pathologies.