The next few articles will outline the first tiny few steps towards achieving perfect capture sharpening, that is deconvolution of an image by the Point Spread Function (PSF) of the lens used to capture it. This is admittedly a complex subject, fraught with a myriad ever changing variables even in a lab, let alone in the field. But studying it can give a glimpse of the possibilities and insights into the processes involved.
I will explain the steps I followed and show the resulting images and measurements. Jumping the gun, the blue line below represents the starting system Spatial Frequency Response (SFR)[1], the black one unattainable/undesirable perfection and the orange one the result of part of the process outlined in this series.
arrives at the front of the lens. It goes through the lens being partly blocked and distorted by it as it arrives at its virtual back end, the Exit Pupil, we’ll call this blocking/distorting function 
. Other than in very simple cases, the Exit Pupil does not necessarily coincide with a specific physical element or Principal surface.
plane is then 
as shown below (not to scale, the product of the two arrays is element-by-element):
