The study you linked defers to The Death Penalty Information Center’s determination of exoneration.

It’s definition is here: https://deathpenaltyinfo.org/stories/criteria-for-inclusion-...

It includes acquittal or dismissal of charges after the original conviction was tossed. But that does not imply actual innocence. For example, if a key piece of evidence is excluded because of an unconstitutional search that could lead to acquittal or dismissal of charges.