The process by which the "dealer" estimates the value of the players hand is at follows:
X = the value of a card (ace = 1, all face cards = 10)
A = total number of with value X not in the dealer's hand
B = initial values for A OR int(20/X) (whichever is smallest)
N = number of cards in my hand
C = total number of cards not in dealers hand = (size of remaining deck + N)
Z = probability that I have a card of value X = (N*B)/C
X = 10
T = (estimated total value of my hand) = Σ(ZX)
X = 1
I may amend this so that the "dealer" assumes that I have a high value if I have not drawn a card for several turns.
here is the video: