Patent ID: 7367880

Claim:
A combine harvester comprising: a feeding system located and configured to gather an amount of plant material as the combine harvester traverses a field; a threshing system located and configured to receive the plant material from the feeding system and thresh at least one selected plant component from the plant material; a cleaning system located and configured to substantially separate the at least one selected plant from residual plant material; a monitoring apparatus located and configured to detect the presence of the at least one selected plant component from residual material in a defined flow path, wherein the monitoring apparatus includes at least one excitation source configured and located to direct an excitation signal toward at least a portion of the defined flow path, and at least one sensor configured to detect a signal initiated by the presence of the at least one selected plant component responsive to the excitation signal; and a structure over which the defined flow path passes, the structure including a reference pattern for detection by the monitoring apparatus, wherein the reference pattern includes indicia representative of the at least one selected plant component.