| 576 | | The transform coefficients for each image series are stored in the corresponding XML documentation file <!ImaDoc>, described in [https://servforge.legi.grenoble-inp.fr/#a3.5Imagedocumentationfiles.xml section 3.5], under the tag <!GeometryCalib>. Calibration coefficients can be displayed with the GUI '''geometry_calib.fig''' described below. Field transform from pixel to physical parameters is performed by the function ''phys.m'' in UVMAT/transform_field, which calls the pointwise transform functions ''phys_XYZ.m'' (from image to physical coordinates) and ''px_XYZ.m'' (from physical to image coordinates), as well as ''phys_ima.m'' which transforms images. When an image or PIV velocity field is opened by uvmat, the transform function 'phys' is automatically loaded as described in section 4.6. |
| | 576 | The transform coefficients for each image series are stored in the corresponding XML documentation file <!ImaDoc>, described in [https://servforge.legi.grenoble-inp.fr/#a3.5Imagedocumentationfiles.xml section 3.5], under the tag <!GeometryCalib>. Calibration coefficients can be displayed with the GUI '''geometry_calib.fig''' described below. Field transform from pixel to physical parameters is performed by the function ''phys.m'' in UVMAT/transform_field, which calls the pointwise transform functions ''phys_XYZ.m'' (from image to physical coordinates) and ''px_XYZ.m'' (from physical to image coordinates), as well as ''phys_ima.m'' which transforms images. When an image or PIV velocity field is opened by uvmat, the transform function 'phys' is automatically loaded as described in section 4.6. |
| 597 | | To reproduce the same calibrationn for image series, open one of the image in the series, and apply again the calibration with the same points, or copy-paste the section GeometryCalib of the XML documentation file with a text editor. |
| 598 | | |
| 599 | | Alternatively the command '''[REPLICATE]''' can be used to calibrate a whole set of experiments in a 'Campaign', using an overview of the data set provided by the GUI '''data_browser.fig''', described in [#a3.7Dataorganisationinaproject section 3.7]. |
| | 597 | To reproduce the same calibrationn for image series, open one of the image in the series, and apply again the calibration with the same points, keeping the GUI geometry_calib opened. |
| | 598 | |
| | 599 | To calibrate at once a set of experiments, a better alternative is the command '''[REPLICATE]'''. Open a folder '''Campaign''', parent of the folders '''Experiment''' to treat. The GUI '''data_browser.fig''', also described in [#a3.7Dataorganisationinaproject section 3.7], then pops up. A two-column display appears, with the list of '''Experiments''' on the left and the list of corresponding '''DataSeries''' on the right. Select the list of experiments to calibrate, and a single camera name in '''DataSeries''', then validate by pressing '''OK'''. |
| 605 | | -'''Section planes:''' deducing the physical coordinates from image coordinates requires information on the section plane. The default assumption is that the objects in the image are in the plane used for calibration, but UVMAT can handle volume scanning by a laser plane. A set of section planes can be defined by their origin positions and rotation angle vectors. Theses planes are labelled by a ''z index'', assumed to be the frame index j (case of volume scan), or the index i modulo the number of slices !NbSlice (case of multiplane scan). The chosen option can be documented in the file <!ImaDoc> by the menu bar command '''[Tools/set slice]''' of '''uvmat.fig'''. A dialog box appears for entering the set of section plane positions ''z'', as lower value, upper value and increment. An angular scan of the laser sheet can be also introduced. After introduction of the multi-plane information, the z-index is displayed in the frame '''[FileIndices]''' of '''uvmat.fig'''. The local z position of the mouse pointer, assumed to lay on the current section plane, is then displayed in '''[text_display]'''. |
| 606 | | |
| 607 | | -'''Water surface''': calibration is best performed inside water to account for refraction effects. However it may be easier to perform it in air, and then take into account the refraction effect. For that purpose the water surface position z (assumed normal to the z coordinate) and refraction index can be introduced with '''[Tools/set slice].''' |
| | 605 | -'''Section planes:''' deducing the physical coordinates from image coordinates requires information on the section plane. The default assumption is that the objects in the image are in the plane used for calibration, but uvmat can handle volume scanning by a laser plane. A set of section planes can be defined by their origin positions and rotation angle vectors. Theses planes are labelled by a ''z index'', assumed to be the frame index j (case of volume scan), or the index i modulo the number of slices !NbSlice (case of 'multilevel' scan). These settings are stored in the xml file <!ImaDoc> as part of the section <!GeometryCalib> and can be edited from '''uvmat.fig''' with the menu bar command '''[Tools/set slice]'''. A dialog box '''set_slices''' appears for entering the first and last section plane positions ''z'', as well as the number of slices and the option 'volume_scan' ('multilevel' otherwise). In the absence of 3D scan put twice the same value for first and last z. Refraction effect can be accounted for if calibration was done in air by introducing the water height (assumed at ''z''=cte). If calibration was already done in water the water height must be '''set with a value below z'''. Finally a tilt angle of the laser sheet, around the ''x'' and ''y'' axis, can be introduced. After introduction of the plane position information, the z-index is displayed in the frame '''[FileIndices]''' of '''uvmat.fig'''. The local ''z'' position of the mouse pointer, assumed to lay on the current section plane, is then displayed in '''[text_display]'''. |
