In this research, an attempt is made to measure the vibrational behavior of polyester filament yarns as a way to identify their physical properties. This is based on the general notion that a change in the physical properties of a string can lead to significant change in its vibrational properties. To conduct the study, a laboratory device equipped with a high-speed digital camera was used to record the vibration of polyester filament yarns at all their points. Video processing was also done to extract the vibration diagrams and to obtain the signal features. The content analysis and the vibration signal processing showed that the filament orientation, yarn count, filament count, appearance of filaments (flat or textured), stimulation distance, and axial tensile force affect some signal characteristics. As the yarn count increased, the frequency, damping, kurtosis of difference signal (FM4) and kurtosis decreased, but the root mean square, four-momentum and energy increased. Moreover, once the stimulation distance increased, the frequency, damping, root mean square, energy, four-momentum and FM4 increased too. An increase in the axial tensile force led to an increase in the frequency and damping but a decrease in the root mean square and energy. Fully drawn yarns (FDY) proved to have the highest frequency, damping, FM4 and kurtosis, and partially oriented yarns (POY) showed the highest energy and four-momentum.

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