Or supersampling, upscaling. It is important to know which resamplers work best for upsampling and to be able to tell (to some extent) what sort of resizing kernel was used on a source in order to reverse bad upscales.
https://diff.pics/AOJ4sBhbe6SX/1 - 2x magnified luma test image using various kernels (and nnedi3)
- 3 - B-Spline - Bicubic b=1, c=0
- 4 - Hermite - Bicubic b=0, c=0
- 5 - Mitchell-Netravali - Bicubic b=1/3, c=1/3
- 6 - Catmull-Rom - Bicubic b=0, c=0.5
- 7 - Sharp Bicubic - Bicubic b=0, c=1
put something about (1-b)/2 for bicubic and b=0, c=X can be any number of values