| 706 | | PIV can be performed by selecting the Matlab function ''civ_series'' as '''[ |
| 707 | | |
| 708 | | -''' {Opening the GUI:} ''' The GUI '''civ.fig''' for PIV calculation can be directly opened by the command '>>civ' on the Matlab prompt. Then open an image or a documentation file (.xml ) with the file browser. ''' '''The''' ''' GUI '''civ.fig''' can be also directly opened from '''uvmat.fig''', by the menu bar command '''[RUN/civ]'''. A third way is just to open the Matlab image ({civ.fig} file) stored after each processing in the directory of the velocity fields. Then just edit it and run a new calculation. |
| | 706 | PIV can be performed by selecting the Matlab function ''civ_series'' as '''[!ActionName]''' in the GUI '''series'''. The same operations can be also performed with the older function ''civ.m'' running with the specific GUI '''civ.fig''', accessible from uvmat by the menu bar command '''[RUN/civ]'''. This older option is still used to run the fortran programs [CIVx]. |
| | 707 | |
| | 708 | -''' Opening the GUI: ''' The GUI '''civ.fig''' for PIV calculation can be directly opened by the command '>>civ' on the Matlab prompt. Then open an image or a documentation file (.xml ) with the file browser. ''' '''The''' ''' GUI '''civ.fig''' can be also directly opened from '''uvmat.fig''', by the menu bar command '''[RUN/civ]'''. A third way is just to open the Matlab image ({civ.fig} file) stored after each processing in the directory of the velocity fields. Then just edit it and run a new calculation. |
| 712 | | -''' {Input file name and indexing:} ''' The root name of the input file is displayed in the edit box '''[RootName]''', and a set of indices can be defined by the edit boxes '''[first_i] ''' (first index), '''[incr_i]''' (increment), '''[last_i ]'''(last index). The GUI offers a wide variety for the choice of image pairs to correlate. In the case of two file indices i and j, a mode for the choice of image pairs can be selected in the popup menu '''[mode]'''. -*'pairj1-j2': a given pair of j indices (or subscript a, b c...) can be chosen in the CIV1 menu '''[list_pair_civ1]''', while the corresponding indices i are set by '''[first_i] ''', '''[incr_i]''' , '''[last_i ]'''. -*'series(Di)': a sliding set of i index pairs is chosen by a set of {reference} indices i_ref given by '''[first_i] ''', '''[incr_i]''' , '''[last_i ]''' and a pair interval defined in '''[list_pair_civ1]''': the first choice 0|1 corresponds to the sliding pair i_ref|i_ref+1. the second choice -1|1 to the sliding pair i_ref-1|i_ref+1,...This mode is generally used with a single image series or movie, but it can be also used in volume scan, with a second index j chosen by '''[first_j] ''', '''[incr_j]''' , '''[last_j ]'''. -*'series(Dj)': operates like 'series(Di)', but with sliding j index pairs. -*comparing two image series: this is made possible by selecting 'displacement' in the popup menu '''[compare]''', which gives access to a browser for selecting the second image series. This second series can be reduced to a single reference image, if it contains no index. The displacement field with respect to this reference image is then obtained for successive times. -*stereo PIV: this option in the menu '''[compare]''' provides the three velocity components by comparing the stereoscopic views from two cameras, see [section 10.6->#sec10.6]. |
| 713 | | |
| 714 | | -''' {Succession of operations:} ''' |
| 715 | | |
| 716 | | The CIV process involves a succession of iterative operations: -*civ1: the initial image correlation process. -*fix1: detection of 'false' velocity vectors according to different criteria. -*patch1: interpolation and filtering on a regular grid, providing access to spatial derivatives of the velocity (diverrgence, curl, strain). -* civ2: advanced image correlation algorithm using the result of civ1 as a first approximation. -* fix2 and patch2: similar as fix1 and patch1, but applied to the civ2 results. This series of operations is chosen by selecting the corresponding check boxes on the left, which give access to the corresponding parameter input panels. Note that the result of each of these operations is stored in the output netcdf file, so the process can be split in several runs. When an existing netcdf velocity file is opened, the GUI '''civ.fig''' is automaticaly configured to perform the next operation (fix1, patch1, civ2...) needed in the process. |
| | 712 | -''' Input file name and indexing: ''' The root name of the input file is displayed in the edit box '''[RootName]''', and a set of indices can be defined by the edit boxes '''[first_i] ''' (first index), '''[incr_i]''' (increment), '''[last_i ]'''(last index). The GUI offers a wide variety for the choice of image pairs to correlate. In the case of two file indices i and j, a mode for the choice of image pairs can be selected in the popup menu '''[mode]'''. -*'pairj1-j2': a given pair of j indices (or subscript a, b c...) can be chosen in the CIV1 menu '''[list_pair_civ1]''', while the corresponding indices i are set by '''[first_i] ''', '''[incr_i]''' , '''[last_i ]'''. -*'series(Di)': a sliding set of i index pairs is chosen by a set of {reference} indices i_ref given by '''[first_i] ''', '''[incr_i]''' , '''[last_i ]''' and a pair interval defined in '''[list_pair_civ1]''': the first choice 0|1 corresponds to the sliding pair i_ref|i_ref+1. the second choice -1|1 to the sliding pair i_ref-1|i_ref+1,...This mode is generally used with a single image series or movie, but it can be also used in volume scan, with a second index j chosen by '''[first_j] ''', '''[incr_j]''' , '''[last_j ]'''. -*'series(Dj)': operates like 'series(Di)', but with sliding j index pairs. -*comparing two image series: this is made possible by selecting 'displacement' in the popup menu '''[compare]''', which gives access to a browser for selecting the second image series. This second series can be reduced to a single reference image, if it contains no index. The displacement field with respect to this reference image is then obtained for successive times. -*stereo PIV: this option in the menu '''[compare]''' provides the three velocity components by comparing the stereoscopic views from two cameras, see [section 10.6->#sec10.6]. |
| | 713 | |
| | 714 | -''' Succession of operations: ''' |
| | 715 | |
| | 716 | The CIV process involves a succession of iterative operations: |
| | 717 | * civ1: the initial image correlation process. |
| | 718 | * fix1: detection of 'false' velocity vectors according to different criteria. |
| | 719 | * patch1: interpolation and filtering on a regular grid, providing access to spatial derivatives of the velocity (diverrgence, curl, strain). |
| | 720 | * civ2: advanced image correlation algorithm using the result of civ1 as a first approximation. |
| | 721 | * fix2 and patch2: similar as fix1 and patch1, but applied to the civ2 results. |
| | 722 | |
| | 723 | This series of operations is chosen by selecting the corresponding check boxes on the left, which give access to the corresponding parameter input panels. Note that the result of each of these operations is stored in the output netcdf file, so the process can be split in several runs. When an existing netcdf velocity file is opened, the GUI '''civ.fig''' is automaticaly configured to perform the next operation (fix1, patch1, civ2...) needed in the process. |
| 721 | | The time interval for each image pair is indicated in '''[list_pair_civ1]''' iif the information is made available, either from a movie file, or from a detected xml file (with the name |
| | 728 | The time interval for each image pair is indicated in '''[list_pair_civ1]''' iif the information is made available, either from a movie file, or from a detected xml file (with the name !RootName.xml). The source of the timing information is indicated in the edit box '''[ImaDoc]'''. Examples of xml files are provides in /XML_SCHEMAS/ImaDoc_templates. In the absence of information, the file index is taken for the time. The time interval for a given index pair may change with time, so the time interval display is taken for given reference indices, given by '''[i_ref]''' and ''' [j_ref].'''. |
