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PIVMat 3.02

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PIVMat 3.02

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27 Apr 2006 (Updated )

A PIV Post-processing and data analysis toolbox

surfheight (PIVMat Toolbox)
surfheight (PIVMat Toolbox)
PIVMat Function Reference<< Prev | Next >> 
surfheight
Surface height reconstruction for FS-SS

Description
H = surfheight(DR, H0, HC, N, [X0,Y0]) computes the surface height H 
for FS-SS measurements (Free-Surface Synthetic Schlieren). 
The input arguments are the displacement field(s) DR, the 
pattern-surface distance H0, the pattern-camera distance HC 
(can be set to infinity, H=inf), the refraction index N and the optical 
center [X0,Y0]. H0, HC and [X0,Y0] are expressed in the same units as R 
(e.g., mm). If N is not specified, N=1.33 by default (water index). If 
the center [X0, Y0] is not specified, the center of the field is taken. 
The center does not need to be inside the field. 
 
FS-SS random dot patterns can be generated using makebospattern. 
 
H = surfheight(..., 'submean') first substracts the mean displacement 
along each direction. This is useful if the incidence angle of the 
camera is not exactly 0. 
 
H = surfheight(..., 'remap') applies the remapping procedure, as 
described in Moisy et al (2009). The resulting height field H is 
smaller than the input displacement field DR, by an amount of about 
L*H0/HC, where L is the field size, H0 the pattern-surface distance and 
HC the pattern-camera distance. 
 
By default, surfheight produces a height field such that MEAN(H)=H0. 
Specify H = surfheight(..., 'nosetzero') if you do not want to apply 
this constraint - in this case, the point (1,1) of the height field 
is equal to H0, but MEAN(H) is arbitrary. 
 
H = surfheight(..., 'verbose') displays the computation progress. 
 
surfheight is based on INTGRAD2.M by J. D'Errico. 
 
Example
 
 
  dr = loadvec('*.vc7'); 
  h = surfheight(dr, 10, 2000); 
  showf(h); 
 
Reference: 
  Moisy, Rabaud, Salsac, "A Synthetic Schlieren method for 
  the measurement of the topography of a liquid interface", 
  Experiments in Fluids (2009). 
 
  See  http://www.fast.u-psud.fr/~moisy/sgbos/tutorial.php 
 
See Also
makebospattern, showf, vec2scal, gradientf. 
 
Published output in the Help browser 
   showdemo surfheight 

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