Is it possible to differentiate a downsampled image from an image captured natively at a given resolution? My gut tells me no, but this certainly isn't my field.
Not my field either. If a picture is just a big 2d array, then i don't think so, you're deleting bits, and information is lost.
If the picture is a collection of summed sin waves, maybe. If the big picture is just sampling more frequently, then maybe it's cheating by looking at the encoding. the smaller resolution will have sampling problems, it'll lose higher frequency data, because it's not sampled enough.
I dunno. I can see the op's point. Maybe there are artifacts introduced by scaling down. Still, regardless of the mechanism, information theory tells us there's no lossless compression. Information is lost, and the NN needs to make something up to fill in the blanks. Looks better than bicubic to me!
If the picture is a collection of summed sin waves, maybe. If the big picture is just sampling more frequently, then maybe it's cheating by looking at the encoding. the smaller resolution will have sampling problems, it'll lose higher frequency data, because it's not sampled enough.
I dunno. I can see the op's point. Maybe there are artifacts introduced by scaling down. Still, regardless of the mechanism, information theory tells us there's no lossless compression. Information is lost, and the NN needs to make something up to fill in the blanks. Looks better than bicubic to me!