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CALWF3 v2.7

CALWF3 v2.7 Release Notes

CALWF3 v2.7 was released for internal use at STScI on May 21, 2012, and was installed in the OPUS operational environment on June 6, 20212.

Relevant PRs for CALWF3 v2.7

PR 64853 CALWF3 IR crcorr should detect and reject negative CR hits

The calwf3 IR crcorr step, which performs up-the-ramp fitting for each image pixel and in the process detects and rejects cosmic-ray hits, currently only searches for jumps from read to read that occur in the positive direction, i.e. jumps that add signal to subsequent reads. On-orbit experience with the WFC3 IR detector has shown that CR's can also leave negative trails in the data, i.e. signal jumps that decrease with subsequent reads. These occur often enough to have a noticeable impact on the scientific quality of the images and therefore the IR crcorr routine should be updated to also search for and reject negative jumps in the pixel ramps.

PR 71004 CALWF3 IR ramp fitting doesn't detect CR's in pixels flagged as bad

The calwf3 IR ramp fitting step (CRCORR) still performs a fit to pixels that are flagged as bad in any way, in order to arrive at a "best effort" output value for the pixel. It has been discovered that the CR jump detection routine is ignoring all pixel samples that have DQ=4 and hence CR's are not detected in pixels flagged with this value in the static bad pixel mask.

The cause of this has been traced to the fact that the DQ=4 value is being overloaded in the ramp fitting routine; this value is also used to flag samples that are detected to contain a noise spike. The CR jump detection routine needs to exclude such spikes, so that they are not mistaken for a CR. Modifying the ramp fitting routine to use a separate (unique) flag value for spikes will allow CR's to be detected in pixels flagged with DQ=4.

PR 71268 WFC3 rej routine cares about case of BUNIT value

It appears that the code (in wf3rej/cr_scaling.c) that checks the BUNIT value is assuming that the string will be in uppercase, i.e. ELECTRONS, which is what the pipeline-produced files usually have. This needs to be changed so that all comparisons first convert the keyvalue to uppercase

Updated 13-Aug-2012 MJD