That's actually just a participial phrase, not an actual passive. In one if his many blog postings on the passive, linguist Geoff Pullum briefly mentions:
I have not opened up the topic of the close relation between passives and predicative adjective constructions (phrases like uninhabited are rather clearly adjectival, since there is no verb *uninhabit, yet we can say Antarctica is mostly uninhabited by humans).
Using a participial phrase as a predicate adjective is most obvious when it appears with a copula:
- The winners are already gone.
But it can also appear to the right of the noun phrase:
- The winners, already long gone, spared no time in celebrating their surprise victory.
That sort of participial phrase can be analysed as an instance of whiz deletion:
- The winners, who were already long gone, spared no time in celebrating their surprise victor.
Predicate adjective phrases like these take the same past-participle inflection of the verb as one uses in passive clauses. But they are not passives for a variety of reasons, the most obvious of which is that they can be used with verbs that can never be passive. That last example used gone, the past participle of the intransitive verb go. So you know for certain it cannot be passive since it’s intransitive.
Another example of this uses the deponent verb to be born as an adjective phrase:
- People who were born before 2001 they liked to call “twen-centers”.
- People born before 2001 they liked to call “twencenters”.
- They liked to call people born before 2001 “twencenters”.
Because you cannot invert born into something in the active, you really can’t call it passive.
A final example of these non-passive adjective phrases is:
- It’s hard to blame kids bigoted against private teachers by years of failing to pass standard tests.
You cannot invert bigoted to say that the the years bigoted the kids, because bigot is not even a verb.
So just because you left university convinced of something doesn’t mean that convinced is a passive. It’s just an adjective (here a past participle) describing your condition, not some sort of passive.