Volume data set files

Echoview can export gridded region inspection data to a volume data set format.

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:

Note: You can also export region inspection data to an text data file. See Export file formats for more information.

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 x Nx + Z x Nx x 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 x 2 node x 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

See also

About inspecting 3D regions
Region gridding algorithms
Viewing exported region inspection data in 3D View
Viewing exported region inspection data in OpenQVis