very blurry

[3d-illusions]

Hi, I wonder if someone might know why I get blurriness comparable to bicubic?

I've posted results here: https://forum.opencv.org/t/why-so-blurry-please/11069/2

Works well with the sample images such as this one, but not with images that are anti-aliased.

this one works well: https://miro.medium.com/max/562/1*7sqZ6SIRlyR6ex1IbFjtFg.webp