Abstract: Systems and methods for detecting anomalies in an envelope including scanning an envelope moving along a conveyor with multiple millimeter wave imaging sensor modules and collecting reflection measurements from the sensor modules. The systems and methods can further include constructing a one or more voxel thick horizontal 3D image of the envelope and then creating an image of the envelope comprising the magnitude of the mean of the one or more voxel layers. The image of the envelope can be fed into a binary logistic regression classifier to provide a probability that the envelope contains an anomaly from the classifier. The systems and methods can include causing the envelope to be diverted from the conveyor for further inspection when the probability is greater than a selected threshold.

Abstract: The present application is directed to image beat pattern mitigation in two-sided reflection based 3-D millimeter wave imaging. In one example, active millimeter-wave (mmWave) imaging illuminates a scene with a source of mmWave energy and forms images based on the reflected energy. Two-sided reflection imaging can be used to overcome the occlusion by the opaque objects that would plague a transmission imaging approach. The system can produce beat-pattern-free 3-D images of the products inside an optically-opaque corrugated cardboard shipping box and further, the two-sided reflection imaging approach with image beat pattern correction shows an increased image volume even if portions of the scene are occluded.