Computer-aided evaluation method for interferograms

Nübel, Rita

doi:10.1007/bf00188255

“…The reader is referred to references [67,68,69] for a technical discussion of DIP methods. A discussion of DIP that specifically focuses on the analysis of interferograms can be found in references [70,71].…”

Section: Fringe Measurement By Digital Image Processingmentioning

confidence: 99%

Laser interferometry - Report #HT-01-2017

Naylor¹

2023

Preprint

0

View full text Add to dashboard Cite

An introduction is given to the optical setup and principle of operation of classical and holographic interferometers that are used for convective he at transfer measurements. The equations for the evaluation of the temperature field are derived and methods of analysis are discussed for both two-dimensional and three-dimensional temperature fields. Emphasis is given to techniques for measuring local heat transfer rates. For two-dimensional fields, a method is presented for measuring the surface temperature gradient directly from a finite (wedge) fringe interferogram. This “direct gradient method” is shown to be most useful for the measurement of low convective heat transfer rates. For three-dimensional fields, the equations for calculating the beam-averaged local heat flux are presented. The measurement of the fluid temperature averaged along the light beam is shown to be approximate. However, an analysis is presented showing that for most cases the error associated with temperature variations in the light beam direction is small. Digital image analysis of interferograms to obtain fringe spacings is also discussed briefly.

show abstract

“…The reader is referred to references [67,68,69] for a technical discussion of DIP methods. A discussion of DIP that specifically focuses on the analysis of interferograms can be found in references [70,71].…”

Section: Fringe Measurement By Digital Image Processingmentioning

confidence: 99%

Laser interferometry - Report #HT-01-2017

Naylor¹

2023

Preprint

0

View full text Add to dashboard Cite

An introduction is given to the optical setup and principle of operation of classical and holographic interferometers that are used for convective he at transfer measurements. The equations for the evaluation of the temperature field are derived and methods of analysis are discussed for both two-dimensional and three-dimensional temperature fields. Emphasis is given to techniques for measuring local heat transfer rates. For two-dimensional fields, a method is presented for measuring the surface temperature gradient directly from a finite (wedge) fringe interferogram. This “direct gradient method” is shown to be most useful for the measurement of low convective heat transfer rates. For three-dimensional fields, the equations for calculating the beam-averaged local heat flux are presented. The measurement of the fluid temperature averaged along the light beam is shown to be approximate. However, an analysis is presented showing that for most cases the error associated with temperature variations in the light beam direction is small. Digital image analysis of interferograms to obtain fringe spacings is also discussed briefly.

show abstract

Computer aided evaluation of interferograms

Bartels-Lehnhoff¹,

Baumann²,

Bretthauer³

et al. 1993

Experiments in Fluids

View full text Add to dashboard Cite

A semi-automatic technique is presented for obtaining the density field from interferograms provided by a Mach-Zehnder setup in infinite fringe width adjustment using short exposure times. The algorithm relies on extracting the fringe edges from the original image and then numbering the resulting polygons according to their order of interference using a graphical editor. The density field is then interpolated between the polygons by calculating its value from the intensity in the original interferogram. This results in highly accurate, high resolution scalar data fields. The results may then be presented in a quasi three-dimensional form using a shading model

show abstract

Computer-aided evaluation method for interferograms

Cited by 4 publications

References 9 publications

Laser interferometry - Report #HT-01-2017

Laser interferometry - Report #HT-01-2017

Laser interferometry - Report #HT-01-2017

Computer aided evaluation of interferograms

Contact Info

Product

Resources

About