Sega Digitizer System is a custom optical-pen based setup for in-house pixel artists, who worked at the Japanese company. There were 3 known version: Digitizer System I, II and III.

According to former Sega graphic designer AGE43, it was attached to a NEC PC-98 with an HDD. Since the Mega Drive was based on the System 16 arcade board, the Digitizer System could be used with both types of hardware. This particular software became an integral part of the production of some of the biggest games out there, including Fantasy Zone.