There is a newly developed technology that involves using a specialized mask to resolve images without the use of a lens. The technology potentially allows the imaging system to avoid limitations imposed by using lenses. The mask is square or rectangular and has an irregular pattern of cells which are selectively blacked out. I forget exactly how it works. Essentially it lets you focus better using the mask. I am trying to remember the name of the technology.
(Note: this is about super resolution imaging without a lens. The question has nothing to do with focusing aids like Bahtinov masks.)