Reference File Types¶
The linearity
step uses a LINEARITY reference file.
LINEARITY Reference File¶
- REFTYPE:
LINEARITY
- Data model:
LinearityModel
The LINEARITY reference file contains pixel-by-pixel polynomial correction coefficients.
Reference Selection Keywords for LINEARITY¶
CRDS selects appropriate LINEARITY references based on the following keyword attributes. All keyword attributes used for file selection are required.
Instrument |
Keyword Attributes |
---|---|
WFI |
instrument, detector, date, time |
Standard ASDF metadata¶
The following table lists the attributes that are required to be present in all reference files. The first column shows the attribute in the ASDF reference file headers, which is the same as the name within the data model meta tree (second column). The second column gives the roman data model name for each attribute, which is useful when using data models in creating and populating a new reference file.
Attribute |
Fully Qualified Path |
---|---|
author |
model.meta.author |
model_type |
model.meta.model_type |
date |
model.meta.date |
description |
model.meta.description |
instrument |
model.meta.instrument.name |
reftype |
model.meta.reftype |
telescope |
model.meta.telescope |
useafter |
model.meta.useafter |
NOTE: More information on standard required attributes can be found here: Standard ASDF metadata
Type Specific Attributes for LINEARITY¶
In addition to the standard reference file attributes listed above, the following attributes are required in LINEARITY reference files, because they are used as CRDS selectors (see Reference Selection Keywords for LINEARITY):
Attribute |
Fully qualified path |
Instruments |
---|---|---|
detector |
model.meta.intstrument.detector |
WFI |
Reference File Format¶
LINEARITY reference files are ASDF format, with 2 data arrays. The format and content of the file is as follows:
Data |
Array Type |
Dimensions |
Data type |
---|---|---|---|
coeffs |
NDArray |
ncols x nrows x ncoeffs |
float32 |
dq |
NDArray |
ncols x nrows |
uint32 |
Each plane of the COEFFS data cube contains the pixel-by-pixel coefficients for the associated order of the polynomial. There can be any number of planes to accommodate a polynomial of any order.