Generalized RF Time-Domain Imaging Technique for Moving Objects on Conveyor Belts in Real Time

In this paper, an attractive time-domain RF imaging technique is proposed for online monitoring of moving objects over conveyor belts. The proposed technique combines the strength of the time-domain approach and the Riccati equation-based ultrawideband reconstruction method in order to image the stratified lossy dielectric medium. The applicability of the proposed method is first tested under stationary condition by reconstructing the permittivity and conductivity image of the target area comprising of various standard samples placed in free space. For moving objects under real-world scenario, two antenna arrays comprised of ultra-wideband Vivaldi elements are designed and tested. These arrays are then employed to produce the 2-D microwave image of various wooden-based samples and human mannequins carrying metal object concealed behind the cloth. The obtained real-time microwave image of the test medium shows that the proposed RF imaging technique is best suited for online monitoring of stationary as well as moving targets, where the structural as well as the electrical properties of the test medium can be obtained through a nondestructive process without using any iterative scheme.