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[IEEE 2018 IEEE 8th International Conference on Consumer Electronics - Berlin - Berlin (2018.9.2-2018.9.5)] 2018 IEEE 8th International Conference on Consumer Electronics - Berlin (ICCE-Berlin) - Using the Hilbert-Huang transform to increase the robustness of video based remote heart-rate measurement from human faces
摘要： Measuring the heart rate(HR) in a conventional way, e.g. using an electrocardiogram, leads to several disadvantages for the patient, such as skin irritation or discomfort. For this reason, remote-based measurement techniques have become more and more popular in recent years. Most of the methods that have been presented use recordings of human faces. These methods recognize minimal changes, invisible to the human eye, in the color spectrum of a persons face to measure heart activity. As a by-product, it is also possible to determine the breath frequency by this method. However, measuring the HR based on a video of someones face is a challenge, as has been reported. One of the biggest problems is ambient light change during the process. To solve this problem and enhance the robustness of the measurement technique, a new approach is proposed in this paper. By using the empirical mode decomposition of the Hilbert Huang transform and independent component analysis (ICA), it is possible to reduce significantly the effects of changes in ambient light conditions. The proposed combination of these two techniques ensures a much greater robustness to changes in light conditions and therefore greater accuracy and can be used in a realistic application environment.
关键词： measurement,BSS,heart rate,ICA,photoplethysmography,Hilbert-Huang transform
更新于2025-09-23 15:22:29
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[IEEE 2019 21st International Middle East Power Systems Conference (MEPCON) - Cairo, Egypt (2019.12.17-2019.12.19)] 2019 21st International Middle East Power Systems Conference (MEPCON) - Experimental Realization for P&O Maximum Power Point Tracking Applied for Single-Stage Three-Phase Grid-Connected Photovoltaic System
摘要： This paper presents a point of care testing device for neurovascular coupling (NVC) from simultaneous recording of electroencephalogram (EEG) and near infrared spectroscopy (NIRS) during anodal transcranial direct current stimulation (tDCS). Here, anodal tDCS modulated cortical neural activity leading to hemodynamic response can be used to identify the impaired cerebral microvessels functionality. The impairments in the cerebral microvessels functionality may lead to impairments in the cerebrovascular reactivity (CVR), where severely reduced CVR predicts the chances of transient ischemic attack and ipsilateral stroke. The neural and hemodynamic responses to anodal tDCS were studied through joint imaging with EEG and NIRS, where NIRS provided optical measurement of changes in tissue oxy-(HbO2) and deoxy-(Hb) hemoglobin concentration and EEG captured alterations in the underlying neuronal current generators. Then, a cross-correlation method for the assessment of NVC underlying the site of anodal tDCS is presented. The feasibility studies on healthy subjects and stroke survivors showed detectable changes in the EEG and the NIRS responses to a 0.526 A/m2 of anodal tDCS. The NIRS system was bench tested on 15 healthy subjects that showed a statistically signi?cant (p < 0.01) difference in the signal-to-noise ratio (SNR) between the ON- and OFF-states of anodal tDCS where the mean SNR of the NIRS device was found to be 42.33 ± 1.33 dB in the ON-state and 40.67±1.23 dB in the OFF-state. Moreover, the clinical study conducted on 14 stroke survivors revealed that the lesioned hemisphere with impaired circulation showed signi?cantly (p < 0.01) less change in HbO2 than the nonlesioned side in response to anodal tDCS. The EEG study on healthy subjects showed a statistically signi?cant (p < 0.05) decrease around individual alpha frequency in the alpha band (8–13 Hz) following anodal tDCS. Moreover, the joint EEG-NIRS imaging on 4 stroke survivors showed an immediate increase in the theta band (4–8 Hz) EEG activity after the start of anodal tDCS at the nonlesioned hemisphere. Furthermore, cross-correlation function revealed a signi?cant (95% con?dence interval) negative cross correlation only at the nonlesioned hemisphere during anodal tDCS, where the log-transformed mean-power of EEG within 0.5–11.25 Hz lagged HbO2 response in one of the stroke survivors with white matter lesions. Therefore, it was concluded that the anodal tDCS can perturb the local neural and the vascular activity (via NVC) which can be used for assessing regional NVC functionality where con?rmatory clinical studies are required.
关键词： Hilbert-Huang transform,Electroencephalogram,neurovascular coupling,small vessel diseases,stroke,near infrared spectroscopy,transcranial direct current stimulation
更新于2025-09-23 15:19:57
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Nonlinear Ultrasonic Detection Method for Delamination Damage of Lined Anti-Corrosion Pipes Using PZT Transducers
摘要： Lined anti-corrosion pipes are widely used in oil and gas, petrochemical, pharmaceutical industries. However, defects, especially delamination, may occur in the production and service of pipes which result in safety accidents. Based on nonlinear ultrasonic theory, this paper studied the delamination detection method using the nonlinear harmonics for lined anti-corrosion pipes. The response characteristics of the anti-corrosion pipe were obtained through a sweep sine response experiment and the preferred excitation frequency was determined. The Wavelet Packet transform and Hilbert–Huang transform is applied for signal process and feature extraction. Then, a series of experiments were carried out and the results were analyzed and discussed. The results showed that a second-order and third-order nonlinear coefficient increased with the delamination damage. The amplitude of second-harmonic is much stronger than the third-order one. The mean squared error of the nonlinear coefficient, which was processed by Wavelet Packet transform and Hilbert–Huang transform, is smaller than wavelet packet transform and Discrete Fourier transform or processed only Hilbert–Huang transform. The higher harmonics can describe the change of delamination damage, which means that the nonlinear ultrasonic detection method could use for damage detection of anti-corrosion pipe. The nonlinear higher-harmonic is sensitive to delamination damage. The nonlinear ultrasonic method has the potential for damage detection for lined anti-corrosion pipes.
关键词： lined anti-corrosion pipes,Hilbert–Huang transform,delamination damage,nonlinear ultrasonic,wavelet packet transform
更新于2025-09-19 17:15:36
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Influence of Measurements Uncertainty on Uncertainty of Gilbert-Huang Transform Modes
摘要： The approach to simplifying the identification of a system using the input and output non-stationary or stationary processes is proposed in the article. The realizations of the process (input and output signals) are converted to the sum of individual components (modes) based on the Hilbert-Huang transform, and then the corresponding modes of this transformation are used for the virtual subsystem identification. The identification quality depends on the measurement uncertainty of both the signal and its Hilbert-Huang modes. The influence of measurements uncertainty of the signal on the individual modes’ uncertainty, considering important factors, is analyzed in the article. The obtained results extend the conditions for solving the problems of system identification.
关键词： measurements uncertainty,system identification,Hilbert-Huang transform
更新于2025-09-19 17:13:59