EbsdLib

EBSDLib is a C++ Library that can read EBSD Files from OEMs and perform basic EBSD processing such as orientation conversion and IPF Color generation. Another important aspect of the library is to be able to convert between the seven orientation representations that are typically used through out materials science and engineering domains.

The DREAM.3D project ( code repository and web site ) uses this library for all of the EBSD processing.

Supported EBSD OEM Data Files

• EDAX/AMETEK: .ang and HDF5 based file formats
• Oxford Instruments: .ctf file format
• Bruker: HDF5 based file format

Please have a look at the unit tests for examples on using the various readers.

Orientation Representations

From/To	Euler	Orientation Matrix	Axis Angle	Rodrigues	Quaternion	Homochoric	Cubochoric
Euler	-	X	X	X	X	a	ah
Orientation Matrix	X	--	X	e	X	a	ah
Axis Angle	o	X	--	X	X	X	h
Rodrigues	o	a	X	--	a	X	h
Quaternion	X	X	X	X	--	X	h
Homochoric	ao	a	X	a	a	--	X
Cubochoric	hao	ha	h	ha	ha	X	--

LEGEND: X = Direct mathematical conversion between the representations lower case letters denote the conversion uses other more basic conversions. For example to go from Euler->Homochoric the conversion process calls the Euler->AxisAngle->OrientationMatrix->Homochoric functions.

In addition to the OrientationTransformation class there are also classes that represent the 11 Laue classes that allow a user to perform Laue class specific calculations including the generation of an IPF Color which is a prevalent visualization scheme within the EBSD community. Note that each vendor has slightly different algorithms and this library has selected to aligh with the AMETEK/EDAX output.

The folder Data/IPF_Legend has premade IPF Legends for most of the Laue classes.

Quaternion Convention

Please also note that by default EbsdLib organizes Quaternions as Vector-Scalar. If your quaternions are layed out as Scalar-Vector there is an extra argument to some functions that you can set to allow the orientation transformations to accept this layout.

Dependent Libraries

EbsdLib is dependent on:

• Qt5 5.15.x (minimum)
• Eigen 3.4
• HDF5 1.10.4 (HDF5 is optional only if you want the HDF5 functionality)

Rotation Convention

By convention this library uses Passive rotations

Citations

D Rowenhorst, A D Rollett, G S Rohrer, M Groeber, M Jackson, P J Konijnenberg and M De Graef et al 2015 Modelling Simul. Mater. Sci. Eng. 23 083501

DOI: https://doi.org/10.1088/0965-0393/23/8/083501

Examples

If you want to transform an Euler angle into a Quaternion the following works:

    Quaternion<float> quat = OrientationTransformation::eu2qu(Orientation<float>(33.0f, 10.0f, 0.0f));

If you have a lot of angles to transform the Orienation class can wrap a pointer instead at which point you can loop over the array of angles. There is also the OrientationConverter class that can mass transform from one representation into another.

Reading from an AMETEK .ang file is straightforward:

AngReader reader;
reader.setFileName(std::string("/path/to/ebsd_scan.ang"));
int32_t err = reader.readFile();
// All of the data from the .ang file is now in memory. You can access it through the pointers
size_t numElements = reader.getNumberOfElements();
float* ptr = reader.getPhi1Pointer();
// The reader will clean up the memory so either tell the reader to Not clean up the pointer or keep the reader in scope.