1. Masks, weights and flatfields
Roeland Masks and weights
Philippe Are WFI flatfields flat?
Ewout Making a supersky?

2. Masks, for what Image statistics Making weights Other,
We could do this more often
Making weights
weight = flat * mask
for sextractor
for coaddition
Other,
cosmic ray program

3. Different Masks Cold pixels Hot pixels Cosmic rays Satellite tracks
bias > mean(bias) + 5*rms(bias)
Hot pixels
flat / convolved(flat) < 0.95
Cosmic rays
Satellite tracks
Saturated pixels
‘low’ gain (co-addition only)

4. Current situation class ColdPixelFrame class HotPixelFrame
class MaskFrame
mask = coldpixels & hotpixels
class MasterWeight
weight = master_flat * mask_frame
class FlagFrame
mask = thresh(weight) * science.cosmic()
class WeightFrame
weight = master_weight * flag.as_mask()

5. New situation Add all operations Use eclipse.pixelmap object
1=good, 0=bad
(de)compress on-the-fly
clean up class-hierarchy mess
simplify ScienceFrame.make()

6. New Situation class ColdPixelMap class HotPixelMap class CosmicMap
class SatelliteMap ?
class Weight
weight = flat * cold&hot&cosmic&sat
weight = weight * thresh(science)
weight = weight * thresh(weight)

7. Error maps Weight is ‘relative error map’
Could make absolute error map and do proper propagation of errors
Nice idea
but, remember the applications