
Here is a summary outline of the steps taken by psphotReadout:

* setup (choose recipe, choose readout, define break-point)
* create mask and weight images if needed, set mask for analysis region
* psphotImageMedian : construct a background model image and subtract it
* psphotFindPeaks   : smooth and find the peak pixels from the smoothed image
  - no pmSource defined yet, only pmPeak
* psphotSourceStats : create sources for each peak and measure their moments
  - pmSource defined here, with pixels covering SKY_OUTER_RADIUS
  - no pmModel is defined yet.
* psphotBasicDeblend : identify blended sources by proximity and valley depth
* psphotRoughClass : source classification guess based on moments
  - set the source.type,mode.
  - re-calculate moments for saturated stars
* psphotChoosePSF : define the psf model
  - this generates model fits to the identified psf stars
    (one for each tested model)
  - these models are not kept (seems like a waste, but later fits must be consistent)
* psphotGuessModels : set the initial PSF model for each object (even EXTENDED)
  - creates modelPSF entries
