Objective parameters from videokymographic images: a user-friendly interface

Videolaringostroboscopy (VLS) is a first choice examination for diagnosis of several laryngeal pathologies. However, in case of strong a-periodicity of the vocal sound, it becomes ineffective in describing subsequent phases of the vocal cycle. To overcome such limitation, a new technique, named videokymography (VKG) has been developed. VKG delivers images from a single line selected from the whole VLS image, at the speed of approximately 8000 line-images/s. However, despite its usefulness, until now no quantitative analysis of VKG images is commercially available. This paper presents a new tool for measuring and tracking quantitative parameters from VKG images. It performs evaluation of left-to-right period, amplitude and phase ratios, as well as of phase symmetry index. Robust techniques for edge detection have been implemented, to reduce both noise and artefacts. The new tool has been provided with a user-friendly interface for managing patients' data and image analysis, according to a set of parameters that can be easily adjusted by the user. VKG images from one non-dysphonic and seven dysphonic subjects were analysed, providing objective parameters useful in diagnosis support.