MeasureDefectsTask¶
MeasureCrosstalkTask is a task to identify detector defects by looking for pixels that are significantly different than the image mean.
Processing summary¶
MeasureDefectsTask runs these operations in a loop over amplifiers:
Measures the clipped mean to estimate the background level.
Subtracts that background from the image.
Identifies pixels that are either above or below the configured sigma thresholds.
Constructs a
Defectsobject from the footprint set of those pixels.
Python API summary¶
from lsst.cp.pipe.cpDefects import MeasureDefectsTask
-
class
MeasureDefectsTask(*, config=None, log=None, initInputs=None, **kwargs) Measure the defects from one exposure
...
- attributeconfig
Access configuration fields and retargetable subtasks.
See also
See the MeasureDefectsTask API reference for complete details.
Retargetable subtasks¶
No subtasks.
Configuration fields¶
badOnAndOffPixelColumnThreshold¶
If BPC is the set of all the bad pixels in a given column (not necessarily consecutive) and the size of BPC is at least ‘badOnAndOffPixelColumnThreshold’, all the pixels between the pixels that satisfy minY (BPC) and maxY (BPC) will be marked as bad, with ‘Y’ being the long axis of the amplifier (and ‘X’ the other axis, which for a column is a constant for all pixels in the set BPC). If there are more than ‘goodPixelColumnGapThreshold’ consecutive non-bad pixels in BPC, an exception to the above is made and those consecutive ‘goodPixelColumnGapThreshold’ are not marked as bad.
badPixelsToFillColumnThreshold¶
If the number of bad pixels in an amplifier column is above this threshold then the full amplifier column will be marked bad. This operation is performed after any merging of blinking columns performed with badOnAndOffPixelColumnThreshold. If thisvalue is less than 0 then no bad column filling will be performed.
biasThreshold¶
If thresholdType==``VALUE``, bias threshold (in ADU) to define hot/bright pixels in bias frame. Unused if thresholdType==``STDEV``.
connections¶
- Data type
lsst.pipe.base.config.MeasureDefectsTaskConfigConnections- Field type
Configurations describing the connections of the PipelineTask to datatypes
darkCurrentThreshold¶
If thresholdType=``VALUE``, dark current threshold (in e-/sec) to define hot/bright pixels in dark images. Unused if thresholdType==``STDEV``.
fracThresholdFlat¶
If thresholdType=``VALUE``, fractional threshold to define cold/dark pixels in flat images (fraction of the mean value per amplifier).Unused if thresholdType==``STDEV``.
goodPixelColumnGapThreshold¶
Size, in pixels, of usable consecutive pixels in a column with on and off bad pixels (see ‘badOnAndOffPixelColumnThreshold’).
nPixBorderLeftRight¶
Number of pixels to exclude from left & right of image when looking for defects.
nPixBorderUpDown¶
Number of pixels to exclude from top & bottom of image when looking for defects.
nSigmaBright¶
If thresholdType=``STDEV``, number of sigma above mean for bright/hot pixel detection. The default value was found to be appropriate for some LSST sensors in DM-17490. Unused if thresholdType==``VALUE``
nSigmaDark¶
If thresholdType=``STDEV``, number of sigma below mean for dark/cold pixel detection. The default value was found to be appropriate for some LSST sensors in DM-17490. Unused if thresholdType==``VALUE``
saturatedColumnDilationRadius¶
Dilation radius (along rows) to use to expand saturated columns to mitigate glow.
saturatedColumnMask¶
Saturated mask plane for dilation.
saturatedPixelsToFillColumnThreshold¶
If the number of saturated pixels in an amplifier column is above this threshold then the full amplifier column will be marked bad. If this value is less than 0then no saturated column filling will be performed.
saveLogOutput¶
Flag to enable/disable saving of log output for a task, enabled by default.
thresholdType¶
- Default
'STDEV'- Field type
strChoiceField(optional)- Choices
'STDEV'Use a multiple of the image standard deviation to determine detection threshold.
'VALUE'Use pixel value to determine detection threshold.
NoneField is optional
Defects threshold type: STDEV or VALUE. If VALUE, cold pixels will be found in flats, and hot pixels in darks. If STDEV, cold and hot pixels will be found in flats, and hot pixels in darks.