A 3-D (stereoscopic) X-ray imaging technique based on linear array detectors

In general the problem of interpreting the three-dimensional structure of an object from an X-ray image is a difficult one. This is due to the almost complete absence of depth cues in a typical radiograph containing as it does only shape and grey scale information. The spatial information usually encountered in two-dimensional images, for example photographs, is missing. Psychological depth cues such as linear z perspective, occlusion and so on are usually present in reinforcing combinations in photographs. In order to provide X-ray images with spatial information an X-ray technique has been developed which introduces the powerful physiological depth cue of binocular parallax into the image. This system was originally designed to assist in the interpretation of X-ray images routinely encountered by operators using standard 2-D X-ray systems for the screening of passenger baggage at airports. The solution to the problem is not however specifically confined to it but is in fact more general in nature. Indeed theoretical designs have already been proposed for other X-ray screening applications including mammography