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High-speed imaging of the larynx

Svante Granqvist

In this project methods for analysis of high-speed laryngoscopic image sequences are developed. 

Example of high-speed recording

These recordings were made at Huddinge University Hospital, department of Logopedics and Phoniatrics. The high-speed camera has a resolution of 256 by 64 pixels and recordings were made at approximately 1900 images per second. The images were recorded with a flexible endoscope fed through the nose. The end of the endoscope is positioned centimeters above the glottis. On this page, the playback speed is reduced to about 3 images per second (the factor may vary depending on your web browser and hardware).
Normal phonation. Every cycle is similar to the other. 
F0 = 115 Hz
(Animation consists of a single cycle within 16 frames that are repeated over and over)
Vocal fry phonation. In this recording a bicyclic oscillation pattern was produced in which the periods appear in groups of two. 
F0 = 120 Hz, F0/2 = 60Hz
(Animation consists of a single group of two cycles within 31 frames that are repeated over and over)

In my licentiate thesis we propose a metod for analysis of recordings, like the one above. The method is based on Fourier transfomations of the light intensity at different locations in the image.







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Last updated: Tuesday, 07-Sep-2004 14:16:45 MEST