LAST_DP_PipeI_BitMask - EranOfek/AstroPack GitHub Wiki
LAST bit mask description
The images are accompanied by 32-bit mask images. Each pixel contains information about possible problems.
In addition, the bitmask are propagated to the source catalogs and stored in the FLAGS column.
For each source, the propagation is done using the OR operator for all the pixels found within a 3 pixel radius from the source position.
Bit mask description
| Bit name | Bit index | Used | Description |
|---|---|---|---|
Saturated |
0 | T | Pixel is saturated. |
LowRN |
1 | T | Pixel noise is low, Var < median(Var) * 0.03; probably a dead pixel. |
HighRN |
2 | T | Pixel noise is high, Var > 20 * median(Var); noisy pixel. |
DarkHighVal |
3 | T | Pixel bias/dark value is high, > 2 * Mean. |
DarkLowVal |
4 | T | Pixel bias/dark value is low, < 0.3 * Mean. |
BiasFlaring |
5 | T | Pixel is possibly flaring, > 20 sigma. |
NaN |
6 | T | Pixel is NaN due to illegal arithmetic operations. |
FlatHighStd |
7 | T | Flat standard error is high, Std / sqrt(N) > 0.01. |
FlatLowVal |
8 | T | Flat normalized value is low, < 0.3. |
LowQE |
9 | T | Pixel has low quantum efficiency, < 0.5 of the nominal value. |
Negative |
10 | T | Negative pixel after processing. |
Interpolated |
11 | F | Pixel value was interpolated. |
Hole |
12 | T | Hole, or anti-star. |
Spike |
13 | F | Diffraction spike. |
CR_DeltaHT |
14 | T | Cosmic ray identified using hypothesis testing against a delta function. |
CR_Laplacian |
15 | F | Cosmic ray identified using a Laplacian filter. |
CR_Streak |
16 | F | Cosmic-ray streak. |
Ghost |
17 | F | Ghost. |
Persistent |
18 | F | Persistent charge. |
Xtalk |
19 | F | Cross talk. |
Streak |
20 | T | Streak. |
ColumnLow |
21 | F | Bad column with low values. |
ColumnHigh |
22 | F | Bad column with high values. |
NearEdge |
23 | T | Pixel is near the image edge. |
NonLinear |
24 | T | Non-linear pixel response. |
Bleeding |
25 | F | Possible bleeding/blooming. |
Overlap |
26 | T | Pixel is in an overlap region. |
SrcNoiseDominated |
27 | T (coadd) | Source-noise-dominated pixel, (Val - Back) > Back. |
GainHigh |
28 | F | In dual-gain detectors: high-gain state. |
CoaddLessImages |
29 | T | Number of images contributing to the coadd is less than X percent. |
SrcDetected |
30 | F | Source detected; all pixels within a 1-FWHM radius from the detected source. |
| 31 | F | Unused |