Methods of Detecting Foreign Objects in Crop Material, and Related Harvesting Machines

A harvesting header, comprising:

• at least one cutting tool;
• a header frame carrying the at least one cutting tool, wherein the header frame is configured to transport cut crop material from the at least one cutting tool through a sensing area to a machine carrying the harvesting header;
• a plurality of electrodes arranged around a periphery of the sensing area;
• and
• a controller configured to:
• cause individual electrodes of the plurality to generate electromagnetic fields by broadcasting electromagnetic radiation into the sensing area;
• and
• measure an attribute related to the electromagnetic fields at some of the plurality of electrodes.

An agricultural machine, comprising:

• a frame configured to transport cut crop material from at least one cutting tool through a sensing area to a crop-processing device;
• a plurality of electrodes arranged around a periphery of the sensing area;
• and
• a controller configured to:
• cause individual electrodes of the plurality to generate electromagnetic fields by broadcasting electromagnetic radiation into the sensing area;
• and
• measure an attribute related to the electromagnetic fields at some of the plurality of electrodes.