Ideally, I would like to see how many times our visitors scrolling down from his/her visit.
If you can isolate the action or information, you can track it with Adobe Analytics.
For "scroll down" actions, I think you'll need some combination of the approach outlined in the Stack Overflow question found here and Launch's "Custom Code" event type:
That said, what question are you trying to answer? Is it truly just to know when someone "scrolls down"? Or, is there another purpose?
I assume that you're tracking through Adobe Launch. In that case, look for the Time and Scroll extension.