Reference Files¶
The dq_init
step uses a MASK reference file.
A list of the allowed DQ values are:
Flags for the DQ, PIXELDQ, and GROUPDQ Arrays.
Bit |
Value |
Name |
Description |
---|---|---|---|
0 |
1 |
DO_NOT_USE |
Bad pixel. Do not use. |
1 |
2 |
SATURATED |
Pixel saturated during exposure |
2 |
4 |
JUMP_DET |
Jump detected during exposure |
3 |
8 |
DROPOUT |
Data lost in transmission |
4 |
16 |
GW_AFFECTED_DATA |
Data affected by the GW read window |
5 |
32 |
PERSISTENCE |
High persistence (was RESERVED_2) |
6 |
64 |
AD_FLOOR |
Below A/D floor (0 DN, was RESERVED_3) |
7 |
128 |
OUTLIER |
Detected as outlier in coadded image |
8 |
256 |
UNRELIABLE_ERROR |
Uncertainty exceeds quoted error |
9 |
512 |
NON_SCIENCE |
Pixel not on science portion of detector |
10 |
1024 |
DEAD |
Dead pixel |
11 |
2048 |
HOT |
Hot pixel |
12 |
4096 |
WARM |
Warm pixel |
13 |
8192 |
LOW_QE |
Low quantum efficiency |
15 |
32768 |
TELEGRAPH |
Telegraph pixel |
16 |
65536 |
NONLINEAR |
Pixel highly nonlinear |
17 |
131072 |
BAD_REF_PIXEL |
Reference pixel cannot be used |
18 |
262144 |
NO_FLAT_FIELD |
Flat field cannot be measured |
19 |
524288 |
NO_GAIN_VALUE |
Gain cannot be measured |
20 |
1048576 |
NO_LIN_CORR |
Linearity correction not available |
21 |
2097152 |
NO_SAT_CHECK |
Saturation check not available |
22 |
4194304 |
UNRELIABLE_BIAS |
Bias variance large |
23 |
8388608 |
UNRELIABLE_DARK |
Dark variance large |
24 |
16777216 |
UNRELIABLE_SLOPE |
Slope variance large (i.e., noisy pixel) |
25 |
33554432 |
UNRELIABLE_FLAT |
Flat variance large |
26 |
67108864 |
RESERVED_5 |
|
27 |
134217728 |
RESERVED_6 |
|
28 |
268435456 |
UNRELIABLE_RESET |
Sensitive to reset anomaly |
29 |
536870912 |
RESERVED_7 |
|
30 |
1073741824 |
OTHER_BAD_PIXEL |
A catch-all flag |
31 |
2147483648 |
REFERENCE_PIXEL |
Pixel is a reference pixel |
MASK Reference File¶
- reftype:
MASK
- Data model:
MaskRefModel
The MASK reference file contains pixel-by-pixel DQ flag values that indicate problem conditions.
Reference Selection Keywords for MASK¶
CRDS selects appropriate MASK references based on the following keywords. MASK is not applicable for instruments not in the table.
Instrument |
Metadata |
---|---|
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 Keywords for MASK¶
In addition to the standard reference file keyword attributes listed above, the following keyword attributes are required in MASK reference files, because they are used as CRDS selectors (see Reference Selection Keywords for MASK):
Attribute |
Fully qualified path |
Instruments |
---|---|---|
detector |
model.meta.instrument.detector |
WFI |
Reference File Format¶
MASK reference files are ASDF format, with one data object. The format and content of the file is as follows:
Data |
Object Type |
Dimensions |
Data type |
---|---|---|---|
dq |
NDArray |
4096 x 4096 |
uint32 |
The values in the dq
array give the per-pixel flag conditions that are
to be propagated into the science exposure’s pixeldq
array.
The dimensions of the dq
array should be equal to the number of columns
and rows in a full-frame readout of a given detector, including reference
pixels.
The ASDF file contains a single dq array.