Metal artifact reduction for CT-based luggage screening

In aviation security, checked luggage is screened by computed tomography (CT) scanning, followed by automatic target recognition from the CT images. Metal objects in the bags cause image artifacts that degrade object representation, leading to increased false alarms. We develop a new method, which isolates and reduces artifacts in an intermediate image, based on a numerical optimization that de-emphasizes metal and has a novel constraint for beam hardening and scatter. Results on test bags showed excellent artifact reduction, even for multiple metal objects.