They use Q-TEC FORS. Q-TEC upscaling is hideous (though FORS isn’t as bad as their old system).
I use nnedi3_rpow2 to upscale - this is necessary when mixing DVD source with HDTV as I occasionally need to do to correct Animax’s Detective Conan airings. But that’s pretty much beside the point - I’m talking about trying to acquire actual 720 or 1080 source, not fake HD made from SD sources.