Goals
- Remove artifacts from coadds by Identifying and masking/Interpolating artifacts in single epoch matchedWarps (CoaddTempExps). Replacement for sigma clipped coadds or "safe-clipped" coadds.
Background and strategic fit
LDM-151 outlines algorithms for artifact detection at various stages of processing in both AP and DRP: snap combination, single epoch processing, and coaddition. During snap subtraction, we will remove cosmic rays and satellite trails (synonymous with “linear features” in LDM-151). During single epoch we will model optical ghosts (ISR using dithered star fields) and identify and remove satellite trails. During coaddition, we will use the time series of warped images to identify artifacts. Most artifacts (see below) will only appear in one of a series of observations. Therefore a stack of warped, PSF-homogenized, background-matched images provide sufficient information to identify and mask pixels affected by artifacts and produce an artifact-free coadd. This epic will address artifact removal in the coaddition stage, by identifying them masking them in the single epoch psfMatchedWarps.
Algorithms used by other multi-epoch imaging projects:
Assumptions
Types of Artifacts fall under a few categories:
Imaged Artifact (Artifact larger than a PSF) vs. Non-Imaged Artifact: Artifact smaller than a PSF. Artifact has not been imaged by the camera, and is produced by CCD electronics.
Single Epoch Artifact vs Persistent Artifact
Requirements
| # | Title | User Story | Importance | Notes |
|---|---|---|---|---|
| 1 | ||||
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Questions
Below is a list of questions to be addressed as a result of this requirements document:
| Question | Outcome |
|---|---|