Authors:
Fabiola M. Villalobos-Castaldi
1
;
José Ruiz-Pinales
2
;
Nicolás C. Kemper-Valverde
1
;
Mercedes Flores-Flores
3
;
Laura G. Ramírez-Sánchez
1
and
Metztli G. Ortiz-Hernández
1
Affiliations:
1
Centro de Ciencias Aplicadas y Desarrollo Tecnológico and UNAM, Mexico
;
2
Universidad de Guanajuato, Mexico
;
3
Tecnológico de Estudios Superiores de Ecatepec, Mexico
Keyword(s):
Time-frequency Analysis, Hilbert Huang Transform, Spontaneous Pupillary Oscillation, Non-traditional Time-series Characterization Scheme.
Related
Ontology
Subjects/Areas/Topics:
Applications and Services
;
Biomedical Engineering
;
Biomedical Signal Processing
;
Computer Vision, Visualization and Computer Graphics
;
Informatics in Control, Automation and Robotics
;
Medical Image Detection, Acquisition, Analysis and Processing
;
Physiological Processes and Bio-Signal Modeling, Non-Linear Dynamics
;
Signal Processing, Sensors, Systems Modeling and Control
;
Time and Frequency Response
;
Time-Frequency Analysis
Abstract:
This paper proposes a new application of the Hilbert-Huang transform (HHT). Pupillogram recordings were analyzed through the non-traditional HHT to investigate patterns in the time-frequency parameters of Spontaneous Pupillary Oscillation (SPO) signals. The traditional Fourier transform is only useful for linear stationary signals analysis, but the HHT was designed for the analysis of non-linear and non-stationary signals. However, the HHT is a more suitable tool to study SPO signals which are fundamentally non-stationary. The intrinsic properties of the Spontaneous Pupillary Oscillation signals were highlighted by the HHT scheme and the results showed that SPO waves present local and intermittent variations through the time span. The numerical parameters demonstrated that it is a wide inter-subject variation in the intrinsic time-frequency parameters contribution from each yielding mode to the total signal content.