Doom—the 1993 version—is one of those classic games that have aged astonishingly well. If you compare its art style to, say, Duke Nukem 3D or Goldeneye, it still looks much better.
But lately, modders and enthusiasts have been experimenting with neural network upscaling technology to bring the game's sprites and textures into the 21st century. Thanks to Doomworld user hidfan a wad file is now available featuring upscaled graphics straight from the maw of AI—specifically, Hidfan used Nvidia's GameWorks SuperResolution and letsenchance.io.
Veeery generally speaking, hidfan fed upsized versions of the textures into these neural networks, retrieved the results, and then downsized them again in order to make them work within the game. It's not all achieved by the network, though: a fair bit of touching up needed to be done in order for things to not look weird.
"Unfortunately [the process] comes with some unwanted pixels here and there and a heavy de-noising work was needed," hidfan writes. "Also the contrast is changed, bright details are brighter, and dark one are darker too, this had to be cleaned as well by removing them and letting the original texture color appear."
Here's how some of the wall textures stand up after the upscale. You can get the wad here.