For someone who purports to be an expert in the medical field....
Areal density resolution in hard X-ray digital imaging system
The concept has been around a while in more visible light related optical disciplines as well...
See page 6 for this reference:
"Thus it is clear that the areal size of a resolution unit
Really, the best you can come up with is an obscure Chinese-language literature reference on X-rays and a simulation
study likely pertaining to the the original Landsat (which launched the following year)? Keep on wiggling...
The resolution of X-ray imaging systems for medical use is specified in lp/mm, just as in photography. For example, this Philips portable unit
that has a specified resolution of up to 3.125 lp/mm. Both the American College of Radiology and US FDA specify a minimum resolution threshold of 2.5 lp/mm (the latter applies specifically to mammography).
Each single pixel of Landsat 1 sampled a rectangular area of the earth's surface that was ~4400 m² (slightly larger than an acre). Even so, the spatial resolution of the MSS imaging system on the Landsats (and other orbital imaging platforms in general) is specified in meters, a linear measure of resolution.
Yes, optical resolution has been and is normally expressed in linear units, especially in optics labs.
Optics labs and college physics professors also insist that the focal plane is nowhere near the film/sensor of a camera, either. Even though camera manufacturers call them exactly that and call the mark they place on the top of their products the "focal plane" symbol. Different communities often have different nomenclature that often assign slightly or even radically different meanings to the same words.
But the concept of areal resolution/density is not a novel one by any means. It's been around for a long time.
More wiggling, the definition of the focal plane isn't relevant to this discussion.
Yes, areal resolution can be measured (although megapixels absent array dimensions are not a valid unit, despite your post that you later grudgingly and incompletely walked back). But this is a photography forum, and optical image resolution is measured with a linear measure.
So, let's go back to the original point of this discussion: @AlanF
stated, “The maximum extra resolution you could get on a 24 Mpx sensor vs a FF 45 Mpx is 1.17x…” You replied, "Wouldn't that be 1.37x?" The answer is no, it would not. It would be 1.17x as Alan stated, not 1.37x as you stated. You were wrong. Period.
At this point, it's just pathetic that you can't simply admit that you were wrong to begin with. Nevertheless, I will accept that you are mentally and/or emotionally incapable of admitting you were wrong, and leave it at that.