Dear Abdullah
This would depend on the deployment mode you are choosing. Inline VLAN Pair mode requires only one interface, this interface can be trunked to carry multiple VLANs.These can be multiple segements as long as they are allowed on the trunk.
Promiscuous mode also requires one port only, and can capture data from 'multiple' segments as long as you mirror all of them to that port.
The "inine interface pair' mode uses up two interfaces for each pair, if you use regular access port configuration only one segement would be covered by one pair.However in some deployments inline interface pair mode can only be trunked, allowing multiple VLANs to pass through the IPS interface pair.
Please rate if helpful.
Regards
Farrukh
