I'd like to if there are divisions of the obscured mistake if so,what are they?

Question
Assalamu Alaykoom
I'd like to if there are divisions of the obscured mistake if so,what are they?
Jazakoom Allah khair

Answer
Wa alaikum assalaam wa rahmatullahi wa barakatuh
Some scholars of tajweed state there are two divisions of obscured mistakes:
1 Mistakes known only by those who are knowledgeable about the Qu'ran, such as leaving out an idghaam or dropping a rule of the noon or meem saakinah. 
2. Mistakes only known by masters of tajweed such as unwanted repetition of the ra', or reading the dhammah incompletely with the English "o" sound, or the kasrah incompletetly with a 'i' sound.
Wa Iyyakum wa-l-muslimeen.