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Laser Doppler Signal Denoising Based on Wavelet Packet Thresholding Method
摘要： In laser Doppler velocimeter (LDV), calculation precision of Doppler shift is affected by noise contained in Doppler signal. In order to restrain the noise interference and improve the precision of signal processing, wavelet packet threshold denoising methods are proposed. Based on the analysis of Doppler signal, appropriate threshold function and decomposition layer number are selected. Heursure, sqtwolog, rigrsure, and minimaxi rules are adopted to get the thresholds. Processing results indicate that signal-to-noise ratio (SNR) and root mean square error (RMSE) of simulated signals with original SNR of 0 dB, 5 dB, and 10 dB in both low- and high-frequency ranges are significantly improved by wavelet packet threshold denoising. A double-beam and double-scattering LDV system is built in our laboratory. For measured signals obtained from the experimental system, the minimum relative error of denoised signal is only 0.079% (using minimaxi rule). The denoised waveforms of simulated and experimental signals are much more smooth and clear than that of original signals. Generally speaking, denoising effects of minimaxi and saqtwolog rules are better than those of heursure and rigrsure rules. As shown in the processing and analysis of simulated and experimental signals, denoising methods based on wavelet packet threshold have ability to depress the noise in laser Doppler signal and improve the precision of signal processing. Owing to its effectiveness and practicability, wavelet packet threshold denoising is a practical method for LDV signal processing.
关键词： wavelet packet threshold denoising,laser Doppler velocimeter,signal-to-noise ratio,double-beam and double-scattering LDV system,root mean square error
更新于2025-09-16 10:30:52
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Laser Doppler Imaging as a Measure of Female Sexual Arousal: Further Validation and Methodological Considerations
摘要： Laser Doppler imaging has recently been applied to the study of female sexual response, with promising results. The current study sought to provide further validation for its use in this capacity, as well as to examine the sexual psychophysiological concepts of genital non-response and return to baseline with this instrument. A sample of healthy heterosexual women without any sexual concerns (N=24) participated in a single testing session design, which included self-report measures and genital imaging with the laser Doppler imager (LDI). During the imaging portion of the study, genital and subjective arousal data were collected while participants watched neutral and erotic film stimuli. The results support the validity of the LDI as a measure of female sexual arousal, and highlight its potential utility in research and clinical applications for sexual function and related difficulties.
关键词： laser Doppler imaging,sexual arousal,measurement of female genital arousal,sexual psychophysiology,sexual response
更新于2025-09-16 10:30:52
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Laser Doppler Signal Processing Based on Trispectral Interpolation of Nuttall Window
摘要： Due to the asynchronous sampling in practical applications, spectrum leakage and fence effect significantly decrease the precision of fast Fourier transform (FFT)-the common signal processing method for laser Doppler velocimeter (LDV). In order to increase the precision of LDV signal processing, trispectral interpolation of Nuttall window is proposed. Based on the comparison and analysis of sidelobe characteristics, four-term first-order, four-term third-order, four-term minimum sidelobe, three-term minimum sidelobe Nuttall windows were adopted to reduce the spectrum leakage. Trispectral interpolation of these four kinds of window functions were carried out to alleviate the fence effect. Processing results of simulated and measured signals verify the validity and accuracy of proposed method. For measured signals in laboratory, the minimum relative error of trispectral interpolation is 0.06% (four-term minimum sidelobe Nuttall window). Meanwhile, for simulated signals, the minimum relative error is only 0.0068% (four-term third-order Nuttall window in low frequency range). Overally speaking, four-term third-order and four-term minimum sidelobe Nuttall windows have better accuracy. Owing to its conciseness and efficience, trispectral interpolation of Nuttall window is a practical method for LDV signal processing.
关键词： trispectral interpolation,spectrum leakage,Laser Doppler velocimeter,Nuttall window,fence effect
更新于2025-09-16 10:30:52
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LASER ANEMOMETRY METHOD FOR PARTICLE VELOCITY MEASUREMENT IN THE BOSE-EINSTEIN CONDENSATE
摘要： Studying of physical and engineering conditions of the process of atom velocity measurement in Bose-Einstein condensate is performed in the paper. In order to provide for the metrological support of the particle laser cooling process it is suggested the laser anemometry method based on measuring the Doppler frequency shift due to scattering of laser radiation by the moving particles to be cooled. The laser anemometry method for estimation of the particle velocity during the particle laser cooling process and the interferential model of the laser Doppler anemometry are provided. The requirements set to technical specifications of the laser Doppler anemometer are determined. The results of the paper form the basis of providing for the metrological support of the particle laser cooling process performed in order to create new frequency standards, the Bose-Einstein condensate and the quantum memory.
关键词： Bose-Einstein condensate,velocity measurement,laser Doppler anemometry,laser cooling of the particles
更新于2025-09-12 10:27:22
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[IEEE 2019 3rd School on Dynamics of Complex Networks and their Application in Intellectual Robotics (DCNAIR) - Innopolis, Russia (2019.9.9-2019.9.11)] 2019 3rd School on Dynamics of Complex Networks and their Application in Intellectual Robotics (DCNAIR) - Synchronization of the process of autonomous regulation of blood circulation with low-frequency components of the laser Doppler flowmetry signal
摘要： The features of the individual dynamics and interaction of the elements of the autonomous regulation of blood circulation and blood flow fluctuations in the microvasculature of the skin were investigated. Phase synchronization of the laser Doppler flowmetry signal with processes of autonomic regulation is revealed. This may indicate the effect of vegetative regulation on the myogenic range of laser Doppler flowmetry.
关键词： Laser Doppler flowmetry,heart rate variability,blood pressure variability,photoplethysmogram,cardiointervalogram,0.1 Hz,statistical significance,phase capture
更新于2025-09-12 10:27:22
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A Traceable High-Accuracy Velocity Measurement by Electro-Optic Dual-Comb Interferometry
摘要： An electro-optic dual-comb Doppler velocimeter for high-accuracy velocity measurement is presented in this paper. The velocity information of the object can be accurately extracted from the change of repetition frequency, which is in the microwave frequency domain and can be locked to an atomic clock. We generate two optical combs by electro-optic phase modulators and trace their repetition frequencies to the rubidium clock. One functions as the measurement laser and the other the reference. Experimentally, we verify its high accuracy in the range of 100–300 mm/s with a maximum deviation of 0.44 mm/s. The proposed velocimeter combines the merits of high accuracy and wide range. In addition, since the repetition frequency used for the measurement is traceable to the rubidium clock, its potential superiority in traceability can be utilized in velocity metrology.
关键词： electro-optic dual-comb interferometry,Traceability,laser Doppler velocimetry
更新于2025-09-12 10:27:22
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[IEEE 2019 41st Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC) - Berlin, Germany (2019.7.23-2019.7.27)] 2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Characterization of Microvascular Post Occlusive Hyperemia Using Laser Doppler Flowmetry Technique in Subjects With Cardiometabolic Disorders
摘要： Introduction: Laser Doppler flowmetry (LDF) provides a noninvasive real-time quantification of relative changes in cutaneous perfusion. Assessment of the microvascular function can provide information on the development of various cardiometabolic disorders. In recent years, non-invasive measurements have gain attention, due to the potential complications associated to invasive procedures. Objective: To differentiate the microvascular function between subjects with cardiometabolic disorders and healthy controls. Methods: Evaluation through LDF during post-occlusive reactive hyperemia (PORH) in patients with or without history of cardiometabolic disorders. Results: Peak values of microvascular flow during post-occlusive reactive hyperemia and both upload and recovery slopes were lesser in the pathological group. Conclusion: A novel approach to characterize LDF during PORH was useful to differentiate patients with cardiometabolic disorders from healthy subjects.
关键词： Laser Doppler flowmetry,cardiometabolic disorders,microvascular function,post-occlusive reactive hyperemia
更新于2025-09-12 10:27:22
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XXX. Messtechnisches Symposium || Methoden zur Sch?tzung der Autokorrelationsfunktion und des Leistungsdichtespektrums aus zuf?llig abgetasteten Laser-Doppler-Daten
摘要： Es werden Methoden zur Sch?tzung der Autokorrelationsfunktion und des Leistungsdichtespektrums aus unregelm??ig, im Idealfall rein zuf?llig abgetasteten Daten vorgestellt. Anwendung finden diese Verfahren in der Verarbeitung von Laser-Doppler-Datens?tzen, die in turbulenten Str?mungen aufgenommen werden, wo die Korrelationsfunktion und das Leistungsdichtespektrum Zugang zum Bereich skaleninvarianten, selbst?hnlichen Verhaltens turbulenter Str?mungen schaffen. Die derzeit bekannten Verfahren zur Bestimmung statistischer Eigenschaften aus zuf?llig abgetasteten Daten werden vorgestellt und systematisiert.
关键词： Spektrum,stochastische Abtastung,Laser-Doppler,Korrelation
更新于2025-09-12 10:27:22
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Perfusion dynamics of the medial sural artery perforator (MSAP) flap in lower extremity reconstruction using laser Doppler perfusion imaging (LDPI): a clinical study
摘要： Perforator flaps are a mainstay in reconstructive surgical practice but are limited by complications, including flap failure, resulting from flap hypoperfusion. This study aimed to characterize the early post-operative perfusion dynamics of the medial sural artery perforator flap in lower extremity reconstruction using laser Doppler perfusion imaging (LDPI). 12 patients, recruited between 2014 and 2015, with lower extremity reconstructions using free MSAP flaps were assessed for perfusion using a hand-held colour Doppler ultrasound device on days 1, 3, and 5 post-operatively. Perfusion at four distinct zones was assessed; whole flap, control zone, perforator zone, and distal zone, by a single operator using a standardized technique. The perforator zone was noted to have the highest relative perfusion of all zones measured across all post-operative days, and this was correlated with whole flap perfusion (r ? 0.82, p ? 0.002). No significant perfusion differences were found within any of the zones over the 5-day period. The perfusion at the distal zone was not found to correlate with either the perforator zone perfusion, flap length, flap length to width ratio or smoking status (p > 0.05). Perfusion of the MSAP flap can adequately be monitored using LDPI at any point throughout the flap, though is highest at the perforator zone, and remains constant in the early post-operative period.
关键词： medial sural artery perforator flap,Laser Doppler perfusion imaging,perfusion zones,perforators
更新于2025-09-12 10:27:22
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Laser Doppler Flowmetry to Differentiate Arterial From Venous Occlusion in Free Tissue Transfer
摘要： Purpose: The differentiation of arterial versus venous occlusion in free tissue transfers has rarely been described. This study investigated changes in blood flow caused by arterial and venous occlusion and the potential for laser Doppler flowmetry to distinguish between these 2 conditions for better clinical assessment and management of free tissue transfer. Methods: Six patients with a mean age of 43.5 years underwent microsurgical free tissue transfer. The venous and arterial blood flow of the vessels and skin flap were monitored using laser Doppler flowmetry with high-frequency pulsed Doppler transducers for vessels and skin before, during, and after clamping the vessels for 10 minutes. Results: The average decreases in blood flow in the artery and vein caused by clamping were 94.4% and 93.8%, respectively. On average, arterial occlusion demonstrated a sudden drop of 67.7% and venous occlusion caused a decrease of 26.6% on laser Doppler flowmetry in free tissue skin. Conclusion: Using a vessel-holding probe, laser Doppler flowmetry could be used to differentiate between arterial and venous occlusion in free tissue transfer, thereby aiding decision-making for better clinical management.
关键词： differentiation,venous occlusion,laser Doppler,arterial occlusion,free tissue transfer
更新于2025-09-12 10:27:22