face detection is a little bit slow

[javadziaratnia]

Hi
I read your article but still I have some questions.
my first question is face detection is a little bit slow is there any way to improve its speed?
my second question is that sometimes it takes 2 o 3 minutes to show to BPM while there is no problem in face detection. so why its takes too long?
my third question is that is the BPM real time? or it has a dealy(eg 3 sec, 4 sec...)
my fourth question is even after 2-3 minutes the heart rate is not accurate. do you have any idea for this?

Regards,
Javad