1. An apparatus for currency discrimination, comprising; first and second stationary scanheads, disposed on opposite sides of a bill transport path, for scanning respective first and second opposing surfaces of each bill of a plurality of bills traveling downstream along said bill transport path and for producing output signals associated with said respective first and second surfaces of each bill, said bills traveling between said scanheads in the direction of a predetermined dimension of said bills at a rate in excess of about 800 bills per minute, each scanned bill having a primary characteristic pattern on one of said first and second surfaces and a secondary characteristic pattern on the other of said first ad second surfaces; a memory for storing master primary characteristic patterns of a plurality of denominations of genuine bills; sampling means for sampling said output signals associated with said respective first and second opposing surfaces of each scanned bill; and signal processing means for (1) determining which surface of said first and second opposing surfaces of each scanned bill includes said primary characteristic pattern in response to said first and second scanheads scanning portions of said first and second opposing surfaces of each bill, and (2) in response to determining which surface of said first and second opposing surfaces of each scanned bill includes said primary characteristic pattern to a predetermined degree of certainty, correlating only an output signal associated with said surface of each scanned bill which includes said primary characteristic pattern with said master primary characteristic patterns to identify the denomination of each scanned bill.