Exporting region inspection data
One method of inspecting 3D regions in Echoview is to export region inspection data. Echoview can export gridded region inspection data to a volume data set format. The internal structure of a 3D region can be viewed in 3rd party software by exporting region inspection data. See About inspecting 3D regions for more information.
You can export region inspection files for 3D regions in scenes.
To export region inspection data:
- Display (or create) a scene.
- Add your 3D region to the scene.
- Press F8 to display the Scene Properties dialog box.
- Select the Analysis page. Check that the correct Analysis variable and Integration algorithm are specified for the region. Click OK.
- On the scene, click the 3D region you want to inspect.
- On the Shortcut menu select Export Region Inspection Data.
- Configure the export on the Export Region Inspection Data dialog box.
- Click Export.
- Select the folder to save to.
- In the Save as type: list, select:
- Volume Data Set raw/dat (*.dat) if you want to use software which can read the Volume data set format.
- CSV file (*.csv) if you want to examine the voxel data in a text format.
- Enter a file name (avoid spaces in the file name if you intend to use OpenQVis, that software does not tolerate them)
- Click Save
Note: You can monitor or cancel the progress of the export in the Gridding Progress dialog box which is displayed when you export your data.
Volume data set files (.dat and .raw)
This format originated from the University of Erlangen and is supported by the OpenQVis software.
The following information has been adapted for Echoview and is sourced from http://openqvis.sourceforge.net/do cu/file format.html.
A volume data set consists of:
- a header file (.dat) in text data format
- a data file (.raw) of raw voxel data in binary format
Note: You can also export region inspection data to a text data file.
Header file (.dat)
The header file contains information about the size and format of the data file and metadata related to the region gridding parameters, the region and the scene.
Header file entry |
Description |
ObjectFileName |
The object file name refers to the name of the data file, which contains the gridded region inspection data. |
TaggedFileName |
Echoview writes "---". |
Resolution |
The resolution of the data set is the number of nodes in the X, Y and Z directions respectively. |
SliceThickness |
The node spacing in (m) in the X, Y and Z directions respectively. |
Format |
Echoview writes "UCHAR" indicating that each voxel occupies one byte in the data (.raw) file. |
NbrTags |
Echoview writes "0". |
ObjectType |
Echoview writes "TEXTURE_VOLUME_OBJECT". OpenQVis requires this value. |
ObjectModel |
Echoview writes "RGBA". OpenQVis requires this value. |
GridType |
Echoview writes "EQUIDISTANT". OpenQVis requires this value. |
GriddingAlgorithm |
The region gridding algorithm used to generate this data. |
NodeRadius |
The node radius (m) used to generate this data. |
PowerParameter |
The power parameter used to generate this data. |
SampleCount |
The number of samples in the 3D region. |
SceneName |
The name of the scene from which the data was exported. |
RegionName |
The name of the 3D region which was exported. |
The following is an example of the information in a .dat file exported by Echoview:
ObjectFileName: RegionInspectionData.raw
TaggedFileName: ---
Resolution: 100 100 100
SliceThickness: 0.321334 0.169526 0.0435563
Format: UCHAR
NbrTags: 0
ObjectType: TEXTURE_VOLUME_OBJECT
ObjectModel: RGBA
GridType: EQUIDISTANT
GriddingAlgorithm: Unweighted mean
NodeRadius: 0.5
PowerParameter: 2
SampleCount: 10795
SceneName: School and bottom
RegionName: School
Data file (.raw)
The data file contains the gridded data (raw voxels) as a binary array. Each voxel is stored as an unsigned 8 bit integer.
The position, in this array, of any voxel with coordinates X, Y and Z is given by:
X + Y × Nx + Z × Nx × Ny
Where:
Nx = number of nodes in the X dimension
Nx = number of nodes in the Y dimension
for example, the following table lists the voxels for a 2 node × 2 node × 2 node object.
Position
in array |
X,Y,Z |
0
|
0,0,0 |
1
|
1,0,0 |
2
|
0,1,0 |
3
|
1,1,0 |
4
|
0,0,1 |
5
|
1,0,1 |
6
|
0,1,1 |
7
|
1,1,1 |
Text region inspection files (.csv)
The text file is in the comma separated variables (CSV) format.
The first row contains Header file entry names. The second row contains the Header file entry (paired) values. The next row is blank. The following rows are divided into row blocks separated by a blank rows. A row block contains the data for a node in the Z direction; columns represent the nodes in the X direction and rows represent the nodes in the Y direction (this is identical to the layout of the data file in the volume data set).
See also
About inspecting 3D regions
Region gridding algorithms
Viewing exported region inspection data in 3D View
Viewing exported region inspection data in OpenQVis