Its non linear because enlarger optics are non linear.
The image of a digital or a film photo is a mosaic. This mosaic can be mathematically enlarged into a large mosaic. If you enlarge far enough you’ll see the individual tiles. This is a linear operation no matter the shape of the tile.
Digital photos do not, however, just make the tiles larger. They could but its not done.
Even before enlarging, they interpolate between tiles to recover color (each pixel in the sensor is monochromatic).
When a picture is displayed, the screen resolution is not that of the photo, so an algorithm has to fit one grid into another. And this is before going into superesoltion techniques.
But none of this would matter if we had a standard, open source, way to utilize digital photos in court. Until then Mr. lawyer can get himself an expert to testify to the validity of each and every still he wants to show the court.
Actually, it's not a superresolution situation. Normally, the resolution of the sensor is higher than that of the screen.
The algorithm used when zooming in a video on any platform I know about is no different as far as distorting as enlarging optics. They are moreso interpolation algorithms than superresolution algorithms.
The image of a digital or a film photo is a mosaic. This mosaic can be mathematically enlarged into a large mosaic. If you enlarge far enough you’ll see the individual tiles. This is a linear operation no matter the shape of the tile.
Digital photos do not, however, just make the tiles larger. They could but its not done.
Even before enlarging, they interpolate between tiles to recover color (each pixel in the sensor is monochromatic).
When a picture is displayed, the screen resolution is not that of the photo, so an algorithm has to fit one grid into another. And this is before going into superesoltion techniques.
But none of this would matter if we had a standard, open source, way to utilize digital photos in court. Until then Mr. lawyer can get himself an expert to testify to the validity of each and every still he wants to show the court.