| 781 | | PIV can be performed by selecting the Matlab function ''civ_series'' as '''[!ActionName]''' in the GUI '''series.fig''': then the '''GUI civ_input''' appears to enter the processing parameters. An image file series must have been entered as input of '''series.fig''', or alternatively a Netcdf file resulting form a previous PIV processing (with conventions '''civdata'''). |
| 782 | | |
| 783 | | An alternative possibility is to use the older Fortran program ''CivX'' from the GUI '''civ.fig'''. This can be called directly on the Matlab prompt, by typing ''>>civ'', or from UVMAT by the menu bar command '''[RUN/PIV (old civ)]'''. |
| 784 | | |
| 785 | | '''- Modes of frame pair indexing''': |
| 786 | | |
| 787 | | * '''PIV''' |
| | 781 | PIV can be performed by selecting the Matlab function ''civ_series'' as '''[!ActionName]''' in the GUI '''series.fig''': then the '''GUI civ_input''' appears to enter the processing parameters. An image file series must be entered as input of '''series.fig'''. |
| | 782 | |
| | 783 | An alternative obsolete possibility (not advised) is to use the older Fortran program ''CivX'' from the GUI '''civ.fig'''. This can be called directly on the Matlab prompt, by typing ''>>civ'', or from UVMAT by the menu bar command '''[RUN/PIV (old civ)]'''. |
| | 784 | |
| | 785 | '''- Modes of frame pair indexing''': PIV is performed by comparing two images in a pair. The images are generally labelled by two indices i and j, see [#a3.3Filenamingandindexing: section 3.3]. A first menu '''[!ListCompareMode]''' on the top left selects one among four modes of operation: |
| | 786 | |
| | 787 | * '''PIV''' (default): makes image comparisons on sliding index pairs, as usual for measuring velocities by particle displacements. A second menu '''[!ListPairMode]''' in the panel '''[!PairIndices]''' then selects one among three possibilities (not always available depending on the file indexing): |
| 788 | 788 | * ''pair j1-j2:'' selects a given j index pair (sometimes denoted by letter index) for the whole time series. This is the most common case for PIV. Pair selection is performed in the menu '''[!ListPairCiv1]''' and '''[!ListPairCiv2]''' for the second iteration Civ2, see below. If timing from an XML file <!ImaDoc> has been detected, this is indicated in the edit box '''[!ImaDoc]''' and the corresponding time intervals are indicated (in ms). For some applications, this time interval may evolve in time, so that reference indices ref_i and ref_j are chosen for the display. |
| 789 | 789 | * series (Di): selects a given index interval for the i index, around a set of reference i indices. The intervals are denoted Di=0|1, -1|1, -1|2, -2|2 ... , corresponding to the index pairs i|i+1, i-1|i+1, i-1|i+2, i-2|i+2 ...around each reference index i. Pair selection is then performed in the menu '''[!ListPairCiv1]''' and '''[!ListPairCiv2]''' like for 'pair j1-j2'. |
