Millimeter-wave Image Reconstruction for Automated Bulk Mail Contraband and Threat Detection

The security of mail has important implications for the safety of military personnel and facilities. High-throughput millimeter-wave imaging technology can be used for automated non-invasive screening of 100% of mail items going from, to, and through military facilities to reduce the risks of contraband, threats, prohibited materials, and dangerous/hazardous goods. However, high-throughput millimeter-wave imaging systems require gapped items to trigger measurements but flats and parcels in mail facilities often present themselves in bulk rather than as single gapped items. To overcome the challenge to image bulk items, this proposed Small Business Innovation Research (SBIR) Phase I project proposes a novel stream-based reconstruction method. The main idea of this novel approach is that whenever a new measurement sample is available, partial image reconstruction is immediately applied on each new measurement and the resulting end image is coherently updated to incorporate the new information. This generates an ōinfiniteö long 3-D-stripmap image. This approach allows high-throughput, low-latency, 3-D millimeter-wave image reconstruction for bulk items such as mail in military or any other mail processing facility