getReadNoise

lsst.cp.pipe.utils.getReadNoise(exposure, ampName, taskMetadata=None, log=None)

Gets readout noise for an amp from ISR metadata.

If possible, this attempts to get the now-standard headers added to the exposure itself. If not found there, the ISR TaskMetadata is searched. If neither of these has the value, warn and set the read noise to NaN.

Parameters:

exposurelsst.afw.image.Exposure

Exposure to check for read noise first.

ampNamestr

Amplifier name.

taskMetadatalsst.pipe.base.TaskMetadata, optional

List of exposures metadata from ISR for this exposure.

loglogging.logger, optional

Log for messages.

Returns:

readNoisefloat

The read noise for this set of exposure/amplifier.