2.3.3.3.136. NXimage_set¶
Status:
base class, extends NXobject
Description:
Base class for reporting a set of images. ...
Base class for reporting a set of images.
The mostly commonly used scanning methods are supported. That is one-, two-, three-dimensional ROIs discretized using regular Euclidean tilings.
Colloquially, an image is understood as a discretized representation of intensity distribution that was detected or simulated for some ROI. When discretized with regular Euclidean tilings the terms pixel and voxel identify the smallest discretization unit. Pixel and voxel are polygonal or polyhedral unit cells respectively of the underlying tiling of the ROI within the reference space. For all other tilings e.g. non-equispaced, the shape and size of pixel and voxel differs. Using the term (image) point is eventually is more appropriate for such tilings. Therefore, all docstrings in this base class refer to points (including pixel and voxel i.e. regular tilings).
Point coordinates identify the location of the barycentre.
For images in reciprocal space in practice, complex numbers are encoded via some formatted pair of real values. Typically, fast algorithms for computing Fourier transformations (FFT) are used to encode images in reciprocal (frequency) space. FFT libraries are used for implementing the key functionalities of these mathematical operations.
Different libraries use different representations and encoding of the images. Details can be found in the respective sections of the typical FFT libraries documentations
NFFT by the Chemnitz group for non-equispaced computations
Users are strongly advised to inspect carefully which specific conventions their library uses to enable storing and modifying the implementation of their code such that the serialized representations as they are detailed here for NeXus match.
It is often the case that several images are combined using processing. In this case, the number of images which are combined in a collection is not necessarily the same for each collection. The NXimage_set base class addresses this logical distinction through the notation of image_identifier and group_identifier concepts. That is image_identifier are always counting from offset in increments of one. as each image is its own entity. By contrast, a group may contain no, or several images. Consequently, group_identifier are not required to be contiguous.
Symbols:
n_img: Number of images in the stack, for stacks the slowest dimension.
n_k: Number of image points along the slow dimension (k equivalent to z).
n_j: Number of image points along the fast dimension (j equivalent to y).
n_i: Number of image points along the fastest dimension (i equivalent to x).
- Groups cited:
Structure:
PROCESS: (optional) NXprocess
Details how NXdata instance were processed from detector readings/raw data.
detector_identifier: (optional) NX_CHAR
Link or name of an :ref:`NXdetector` instance with which the data were ...
Link or name of an NXdetector instance with which the data were collected.
source: (optional) NXserialized
Resolvable data artifact (e.g. file) from which all values in the :ref:`NXda ...
Resolvable data artifact (e.g. file) from which all values in the NXdata instances in this NXimage_set were loaded during parsing.
Possibility to document from which specific other serialized resource as the source pieces of information were processed when using NeXus as a semantic file format to serialize that information differently.
The group in combination with an added field absolute_path therein adds context.
absolute_path: (optional) NX_CHAR
Reference to a location inside the artifact that points to the specific gr ...
Reference to a location inside the artifact that points to the specific group of values that were processed if the artifacts contains several groups of values and thus further resolving of ambiguities is required.
PROGRAM: (optional) NXprogram
Program used for processing.
image_1d: (optional) NXdata
One-dimensional image.
intensity: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_i]) {units=NX_UNITLESS} ⤆
Intensity for real-valued images as an alternative for real. ...
Intensity for real-valued images as an alternative for real. Magnitude of the image intensity for complex-valued data.
real: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_i]) {units=NX_UNITLESS} ⤆
Real part of the image intensity per point.
imag: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_i]) {units=NX_UNITLESS} ⤆
Imaginary part of the image intensity per point.
complex: (optional) NX_COMPLEX (Rank: 1, Dimensions: [n_i]) {units=NX_UNITLESS}
Image intensity as a complex number as an alternative to real and ...
Image intensity as a complex number as an alternative to real and imaginary fields if values are stored as interleaved complex numbers.
axis_i: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_i]) {units=NX_LENGTH} ⤆
image_2d: (optional) NXdata
Two-dimensional image.
intensity: (optional) NX_NUMBER (Rank: 2, Dimensions: [n_j, n_i]) {units=NX_UNITLESS} ⤆
Intensity for real-valued images as an alternative for real. ...
Intensity for real-valued images as an alternative for real. Magnitude of the image intensity for complex-valued data.
real: (optional) NX_NUMBER (Rank: 2, Dimensions: [n_j, n_i]) {units=NX_UNITLESS} ⤆
Real part of the image intensity per point.
imag: (optional) NX_NUMBER (Rank: 2, Dimensions: [n_j, n_i]) {units=NX_UNITLESS} ⤆
Imaginary part of the image intensity per point.
complex: (optional) NX_COMPLEX (Rank: 2, Dimensions: [n_j, n_i]) {units=NX_UNITLESS}
Image intensity as a complex number as an alternative to real and ...
Image intensity as a complex number as an alternative to real and imaginary fields if values are stored as interleaved complex numbers.
axis_j: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_j]) {units=NX_LENGTH} ⤆
axis_i: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_i]) {units=NX_LENGTH} ⤆
image_3d: (optional) NXdata
Three-dimensional image.
intensity: (optional) NX_NUMBER (Rank: 3, Dimensions: [n_k, n_j, n_i]) {units=NX_UNITLESS} ⤆
Intensity for real-valued images as an alternative for real. ...
Intensity for real-valued images as an alternative for real. Magnitude of the image intensity for complex-valued data.
real: (optional) NX_NUMBER (Rank: 3, Dimensions: [n_k, n_j, n_i]) {units=NX_UNITLESS} ⤆
Real part of the image intensity per point.
imag: (optional) NX_NUMBER (Rank: 3, Dimensions: [n_k, n_j, n_i]) {units=NX_UNITLESS} ⤆
Imaginary part of the image intensity per point.
complex: (optional) NX_COMPLEX (Rank: 3, Dimensions: [n_k, n_j, n_i]) {units=NX_UNITLESS}
Image intensity as a complex number as an alternative to real and ...
Image intensity as a complex number as an alternative to real and imaginary fields if values are stored as interleaved complex numbers.
axis_k: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_k]) {units=NX_LENGTH} ⤆
axis_j: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_j]) {units=NX_LENGTH} ⤆
axis_i: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_i]) {units=NX_LENGTH} ⤆
stack_1d: (optional) NXdata
Collection of image_1d.
intensity: (optional) NX_NUMBER (Rank: 2, Dimensions: [n_img, n_i]) {units=NX_UNITLESS} ⤆
Intensity for real-valued images as an alternative for real. ...
Intensity for real-valued images as an alternative for real. Magnitude of the image intensity for complex-valued data.
real: (optional) NX_NUMBER (Rank: 2, Dimensions: [n_img, n_i]) {units=NX_UNITLESS} ⤆
Real part of the image intensity per point.
imag: (optional) NX_NUMBER (Rank: 2, Dimensions: [n_img, n_i]) {units=NX_UNITLESS} ⤆
Imaginary part of the image intensity per point.
complex: (optional) NX_COMPLEX (Rank: 2, Dimensions: [n_img, n_i]) {units=NX_UNITLESS}
Image intensity as a complex number as an alternative to real and ...
Image intensity as a complex number as an alternative to real and imaginary fields if values are stored as interleaved complex numbers.
group_identifier: (optional) NX_INT (Rank: 1, Dimensions: [n_img]) {units=NX_UNITLESS}
image_identifier: (optional) NX_INT (Rank: 1, Dimensions: [n_img]) {units=NX_UNITLESS}
axis_i: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_i]) {units=NX_LENGTH} ⤆
stack_2d: (optional) NXdata
Collection of two-dimensional images.
intensity: (optional) NX_NUMBER (Rank: 3, Dimensions: [n_img, n_j, n_i]) {units=NX_UNITLESS} ⤆
Intensity for real-valued images as an alternative for real. ...
Intensity for real-valued images as an alternative for real. Magnitude of the image intensity for complex-valued data.
real: (optional) NX_NUMBER (Rank: 3, Dimensions: [n_img, n_j, n_i]) {units=NX_UNITLESS} ⤆
Real part of the image intensity per point.
imag: (optional) NX_NUMBER (Rank: 3, Dimensions: [n_img, n_j, n_i]) {units=NX_UNITLESS} ⤆
Imaginary part of the image intensity per point.
complex: (optional) NX_COMPLEX (Rank: 3, Dimensions: [n_img, n_j, n_i]) {units=NX_UNITLESS}
Image intensity as a complex number as an alternative to real and ...
Image intensity as a complex number as an alternative to real and imaginary fields if values are stored as interleaved complex numbers.
group_identifier: (optional) NX_INT (Rank: 1, Dimensions: [n_img]) {units=NX_UNITLESS}
image_identifier: (optional) NX_INT (Rank: 1, Dimensions: [n_img]) {units=NX_UNITLESS}
axis_j: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_j]) {units=NX_LENGTH} ⤆
axis_i: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_i]) {units=NX_LENGTH} ⤆
stack_3d: (optional) NXdata
Collection of three-dimensional images.
intensity: (optional) NX_NUMBER (Rank: 4, Dimensions: [n_img, n_k, n_j, n_i]) {units=NX_UNITLESS} ⤆
Intensity for real-valued images as an alternative for real. ...
Intensity for real-valued images as an alternative for real. Magnitude of the image intensity for complex-valued data.
real: (optional) NX_NUMBER (Rank: 4, Dimensions: [n_img, n_k, n_j, n_i]) {units=NX_UNITLESS} ⤆
Real part of the image intensity per point.
imag: (optional) NX_NUMBER (Rank: 4, Dimensions: [n_img, n_k, n_j, n_i]) {units=NX_UNITLESS} ⤆
Imaginary part of the image intensity per point.
complex: (optional) NX_COMPLEX (Rank: 4, Dimensions: [n_img, n_k, n_j, n_i]) {units=NX_UNITLESS}
Image intensity as a complex number as an alternative to real and ...
Image intensity as a complex number as an alternative to real and imaginary fields if values are stored as interleaved complex numbers.
group_identifier: (optional) NX_INT (Rank: 1, Dimensions: [n_img]) {units=NX_UNITLESS}
image_identifier: (optional) NX_INT (Rank: 1, Dimensions: [n_img]) {units=NX_UNITLESS}
axis_k: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_k]) {units=NX_LENGTH} ⤆
axis_j: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_j]) {units=NX_LENGTH} ⤆
axis_i: (optional) NX_NUMBER (Rank: 1, Dimensions: [n_i]) {units=NX_LENGTH} ⤆
Hypertext Anchors¶
List of hypertext anchors for all groups, fields, attributes, and links defined in this class.
