Velocity despiking: Difference between revisions

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|year= 2002|doi= 10.1061/􏰠ASCE􏰐0733-9429􏰠2002􏰐128:1􏰠117􏰐}}</ref>.  
|year= 2002|doi= 10.1061/􏰠ASCE􏰐0733-9429􏰠2002􏰐128:1􏰠117􏰐}}</ref>.  


Several techniques exist for de-spiking. The most used with  [[Acoustic-Doppler Velocimeters| acoustic-Doppler velocimeters]] are the phase-space thresholding techniques <ref name="GoringNikora"/>. Other techniques currently being investigated by the subgroup are those used in atmospheric turbulence studies <ref name="Starkenburg">{{Cite journal|authors= D. Starkenburg, S. Metzger, G.J. Fochesatto, J.G Alfieri, R. Gens, A. Prakash and J. Cristobal|journal_or_publisher=  J. Atmos. Oceanic Technoly|paper_or_booktitle= Assessment of Despiking Methods for Turbulence Data in Micrometeorology
Several techniques exist for despiking. The most used with  [[Acoustic-Doppler Velocimeters| acoustic-Doppler velocimeters]] are the phase-space thresholding techniques <ref name="GoringNikora"/>. Other techniques currently being investigated by the subgroup are those used in atmospheric turbulence studies <ref name="Starkenburg">{{Cite journal|authors= D. Starkenburg, S. Metzger, G.J. Fochesatto, J.G Alfieri, R. Gens, A. Prakash and J. Cristobal|journal_or_publisher=  J. Atmos. Oceanic Technoly|paper_or_booktitle= Assessment of Despiking Methods for Turbulence Data in Micrometeorology
|year= 2016|doi= 10.1175/JTECH-D-15-0154.1􏰐}}</ref>, in particular the median filter despiking technique <ref name="Brock">{{Cite journal|authors=F.V. Brock|journal_or_publisher=  J. Atmos. Oceanic Technoly|paper_or_booktitle= A nonlinear filter to remove impulse noise from meteorological data
|year= 2016|doi= 10.1175/JTECH-D-15-0154.1􏰐}}</ref>, in particular the median filter despiking technique <ref name="Brock">{{Cite journal|authors=F.V. Brock|journal_or_publisher=  J. Atmos. Oceanic Technoly|paper_or_booktitle= A nonlinear filter to remove impulse noise from meteorological data
|year= 1986|doi= 10.1175/1520-0426(1986)003,0051:ANFTRI.2.0.CO;2􏰐}}</ref>, which derives its threshold for identifying spurious spikes from the data itself.  
|year= 1986|doi= 10.1175/1520-0426(1986)003,0051:ANFTRI.2.0.CO;2􏰐}}</ref>, which derives its threshold for identifying spurious spikes from the data itself.


==Filter based methods==
==Filter based methods==

Revision as of 19:05, 24 November 2021


Overview

Any measured signal may be contaminated by spikes. These spikes are typically short-lived and transient, which result in sudden change in the measured signal.

Example velocities measured by an acoustic-Doppler velocimeters.

Spikes in velocities measured by acoustic-Doppler velocimeters can result from aliasing of the Doppler signal, in particular when pulses become contaminated by reflecting from complex objects and boundaries [1].

Several techniques exist for despiking. The most used with acoustic-Doppler velocimeters are the phase-space thresholding techniques [1]. Other techniques currently being investigated by the subgroup are those used in atmospheric turbulence studies [2], in particular the median filter despiking technique [3], which derives its threshold for identifying spurious spikes from the data itself.

Filter based methods

Phase-space thresholding methods

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Notes

  1. 1.0 1.1 D. G. Goring and V.I. Nikora. 2002. Despiking Acoustic Doppler Velocimeter Data. Journal of Hydraulic Engineering. doi:10.1061/􏰠ASCE􏰐0733-9429􏰠2002􏰐128:1􏰠117􏰐
  2. D. Starkenburg, S. Metzger, G.J. Fochesatto, J.G Alfieri, R. Gens and A. Prakash and J. Cristobal. 2016. Assessment of Despiking Methods for Turbulence Data in Micrometeorology. J. Atmos. Oceanic Technoly. doi:10.1175/JTECH-D-15-0154.1􏰐
  3. F.V. Brock. 1986. A nonlinear filter to remove impulse noise from meteorological data. J. Atmos. Oceanic Technoly. doi:10.1175/1520-0426(1986)003,0051:ANFTRI.2.0.CO;2􏰐

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