A method of providing input to an inspection system for inspecting material laid by a composite material placement machine. A placement machine component that drives a first encoder output is used to drive a second encoder output. The second encoder output is used to trigger image acquisition by the inspection system. Existing components can be used to provide encoding capability for a placement machine inspection system. Because encoder output signals for material placement and for material inspection are driven by the same component, material placement locations can be determined more precisely compared with other methods.