Changes between Version 144 and Version 145 of UvmatHelp


Ignore:
Timestamp:
Jan 14, 2015, 2:32:59 PM (6 years ago)
Author:
vaillant1p
Comment:

--

Legend:

Unmodified
Added
Removed
Modified
  • UvmatHelp

    v144 v145  
    827827 * vec_F(i)=2: (only in civ1) we keep the less accurate Hart result (resulting from combining correlation functions  from neighborhing points) and  vec_C(i)=-1 is chosen by convention. Reference: Hart D. P. (2000) 'PIV error correction',{ Exp. Fluids} '''29''', 13-22.
    828828 * vec_F(i)=3: the optimisation of the correlation function is unstable  or  local Intensity rms of the image =0
    829  * vec_F(i)=4:only in civ2: the difference between the estimator and the result is more than 1 pixel. The two criteria, vec_F(i)=-2, and 3, should be selected (default options). The criterium vec_F=2 (Hart) should not be selected, while vec_F=4 (for civ2) could be selected only for excellent data (otherwise it may be too strict).   -''' {Threshold on the image correlation}  ''' (vec_C) can be introduced by the edit box [thresh_vecC] (value between 0 and 1). It removes vectors with poor correlation. 
    830 
    831 ''' {Threshold on the velocity modulus } ''' (expressed in pixels): it can remove either too small values  (menu '''[inf_sup1]''' set to '<'), or excessive values (menu '''[inf_sup1]''' set to '>'). Erratic zero velocity vectors, produced by a fixed image background, can be eliminated by this criterium. These criteria can be as well applied to the difference with a reference field, defined by a file series (edit box '''[ref_fix1]''') and a field inside the file (menu '''[field_ref1]''').
     829 * vec_F(i)=4:only in civ2: the difference between the estimator and the result is more than 1 pixel. The two criteria, vec_F(i)=-2, and 3, should be selected (default options). The criterium vec_F=2 (Hart) should not be selected, while vec_F=4 (for civ2) could be selected only for excellent data (otherwise it may be too strict).   
     830
     831''' {Threshold on the image correlation:}  ''' (vec_C) can be introduced by the edit box [thresh_vecC] (value between 0 and 1). It removes vectors with poor correlation. 
     832
     833''' {Threshold on the velocity modulus:} ''' (expressed in pixels): it can remove either too small values  (menu '''[inf_sup1]''' set to '<'), or excessive values (menu '''[inf_sup1]''' set to '>'). Erratic zero velocity vectors, produced by a fixed image background, can be eliminated by this criterium. These criteria can be as well applied to the difference with a reference field, defined by a file series (edit box '''[ref_fix1]''') and a field inside the file (menu '''[field_ref1]''').
    832834
    833835''' {Mask fix:} '''  It has the same effect as the one used in civ1, but the removed vectors are kept in memory, labelled as false.