NXimage_set_em_kikuchi¶
Status:
base class, extends NXobject
Description:
Electron backscatter diffraction (EBSD) Kikuchi pattern.
The container can also store data related to a post-processing of these Kikuchi pattern, which is the backbone of orientation microscopy especially in materials science and materials engineering.
Based on a fuse of the M. A. Jackson et al. of the DREAM.3D community and the open H5OINA format of Oxford Instruments P. Pinard et al.
EBSD can be used, usually with FIB/SEM microscopes, for three-dimensional orientation microscopy. So-called serial section analyses. For a detailed overview of these techniques see e.g.
With serial-sectioning this involves however always a sequence of measuring, milling. In this regard, each serial section (measuring) and milling is an own NXevent_data_em instance and thus there such a three-dimensional characterization should be stored as a set of two-dimensional data, with as many NXevent_data_em instances as sections were measured.
These measured serial sectioning images need virtually always post-processing to arrive at the aligned and cleaned image stack respective digital microstructure representation as (a representative) volume element. Several software packages are available for this post-processing. For now we do not consider metadata of these post-processing steps as a part of this base class.
Symbols:
n_p: Number of scan points, one pattern per scan point.
n_y: Number of pixel per Kikuchi pattern in the slow direction
n_x: Number of pixel per Kikuchi pattern in the fast direction
- Groups cited:
Structure:
grid_type: (optional) NX_CHAR
Which pixel primitive shape is used.
Any of these values:
square
|hexagon
step_size: (optional) NX_NUMBER (Rank: 1, Dimensions: [2]) {units=NX_LENGTH}
The prescribed step size. First value is for the slow changing, second value is for the fast changing dimension.
DATA: (optional) NXdata
Collected Kikuchi pattern as an image stack.
intensity: (optional) NX_NUMBER (Rank: 3, Dimensions: [n_p, n_y, n_x]) {units=NX_UNITLESS}
@long_name: (optional) NX_CHAR
Kikuchi pattern intensity
image_id: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_p]) {units=NX_UNITLESS}
@long_name: (optional) NX_CHAR
Kikuchi pattern identifier
ypos: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_y]) {units=NX_LENGTH}
@long_name: (optional) NX_CHAR
Label for the y axis
xpos: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_x]) {units=NX_LENGTH}
@long_name: (optional) NX_CHAR
Label for the x axis
calibration: (optional) NXprocess
oim: (optional) NXprocess
OIM, orientation imaging microscopy. Post-processing of the Kikuchi pattern to identify orientations.
pattern_quality: (optional) NX_FLOAT (Rank: 1, Dimensions: [n_p]) {units=NX_UNITLESS}
pattern_center: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_p]) {units=NX_LENGTH}
detector_distance: (optional) NX_FLOAT (Rank: 1, Dimensions: [n_p]) {units=NX_LENGTH}
background_correction: (optional) NXprocess
Details about the background correction applied to each Kikuchi pattern.
band_detection: (optional) NXprocess
mode: (optional) NX_CHAR
How are Kikuchi bands detected
Obligatory value:
center
band_contrast: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_p]) {units=NX_UNITLESS}
band_slope: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_p]) {units=NX_UNITLESS}
bands: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_p]) {units=NX_UNITLESS}
How many bands were detected in the pattern.
indexing: (optional) NXprocess
mode: (optional) NX_CHAR
How are pattern being indexed?
Obligatory value:
optimize_bd
min_bands: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_p])
Minimum number of bands required to index the pattern
status: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_p]) {units=NX_UNITLESS}
Which return value did the indexing algorithm yield for each pattern.
Details about bad pixels
Too high angular deviation
No solution
Not analyzed
Success
Unexpected errors
phase_identifier: (optional) NX_UINT (Rank: 1, Dimensions: [n_p]) {units=NX_UNITLESS}
Labels referring to the phase_identifier for each pattern (from reflectors) that matched best.
mean_angular_deviation: (optional) NX_FLOAT (Rank: 1, Dimensions: [n_p]) {units=NX_ANGLE}
confidence_index: (optional) NX_FLOAT (Rank: 1, Dimensions: [n_p]) {units=NX_UNITLESS}
reflector: (optional) NXcollection
Lattice planes used as reflectors for indexing pattern in electron-backscatter diffraction (EBSD). One collection for each reflector.
unit_cell_abc: (optional) NX_FLOAT (Rank: 1, Dimensions: [3]) {units=NX_LENGTH}
Crystallography unit cell parameters a, b, and c
unit_cell_alphabetagamma: (optional) NX_FLOAT (Rank: 1, Dimensions: [3]) {units=NX_ANGLE}
Crystallography unit cell parameters alpha, beta, and gamma
unit_cell_class: (optional) NX_CHAR
Any of these values:
triclinic
monoclinic
orthorhombic
tetragonal
rhombohedral
hexagonal
cubic
space_group: (optional) NX_CHAR
Crystallographic space group
laue_group: (optional) NX_CHAR
Laue group
phase_identifier: (optional) NX_UINT {units=NX_UNITLESS}
Numeral identifier for each phase. The value 0 is reversed for the unknown phase.
phase_name: (optional) NX_CHAR
Name of the phase/alias.
number_of_reflectors: (optional) NX_UINT
miller_indices: (optional) NX_NUMBER (Rank: 2, Dimensions: [number_of_reflectors, 6]) {units=NX_UNITLESS}
Miller indices \((hkl)[uvw]\).
binning: (optional) NXcollection
mode: (optional) NX_CHAR
Free-text description for instrument specific settings
binning: (optional) NX_UINT (Rank: 1, Dimensions: [2]) {units=NX_UNITLESS}
How is the camera signal binned. First the number of pixel along the slow direction. Second the number of pixel along the fast direction.
hough_transformation: (optional) NXprocess
resolution: (optional) NX_NUMBER {units=NX_UNITLESS}
profiling: (optional) NXcollection
acquisition_speed: (optional) NX_FLOAT {units=NX_FREQUENCY}
Average number of patterns taken on average.
acquisition_time: (optional) NX_FLOAT {units=NX_TIME}
Wall-clock time the acquisition took.
hit_rate: (optional) NX_FLOAT {units=NX_DIMENSIONLESS}
Fraction of successfully indexed pattern of the set.
Hypertext Anchors¶
List of hypertext anchors for all groups, fields, attributes, and links defined in this class.
/NXimage_set_em_kikuchi/hough_transformation/resolution-field
/NXimage_set_em_kikuchi/oim/band_detection/band_contrast-field
/NXimage_set_em_kikuchi/oim/indexing/mean_angular_deviation-field
/NXimage_set_em_kikuchi/oim/indexing/reflector/laue_group-field
/NXimage_set_em_kikuchi/oim/indexing/reflector/miller_indices-field
/NXimage_set_em_kikuchi/oim/indexing/reflector/number_of_reflectors-field
/NXimage_set_em_kikuchi/oim/indexing/reflector/phase_identifier-field
/NXimage_set_em_kikuchi/oim/indexing/reflector/phase_name-field
/NXimage_set_em_kikuchi/oim/indexing/reflector/space_group-field
/NXimage_set_em_kikuchi/oim/indexing/reflector/unit_cell_abc-field
/NXimage_set_em_kikuchi/oim/indexing/reflector/unit_cell_alphabetagamma-field
/NXimage_set_em_kikuchi/oim/indexing/reflector/unit_cell_class-field