Microwave Moisture Imaging of Cotton Bales with Metal Wire-Ties

Abstract: The use of microwave imaging is becoming more prevalent for detection of interior hidden defects in manufactured and packaged materials.  In applications for detection of hidden moisture, microwave tomography can be used to image the material and then perform an inverse calculation to derive an estimate of the variability of the hidden material, such as internal moisture, thereby alerting personnel to damaging levels of the hidden moisture before material degradation occurs.  One impediment to this type of imaging occurs when nearby objects create strong reflections that create destructive and constructive interference, at the receiver, as the material is conveyed past the imaging antenna array.  In an effort to remove the influence of the reflectors, such as metal bale ties, research was conducted to develop techniques for removal of the influence of the local proximity reflectors from the microwave images.