06195444 is referenced by 82 patents and cites 26 patents.

A method and apparatus for detecting concealed objects in computed tomography data are disclosed. Sheet-shaped objects such as sheet explosives can be detected by a CT scanning system, in particular, a CT baggage scanning system. The invention analyzes CT voxels in a subregion in proximity to the sheet object to determine if the sheet object is concealed in an electronic device or is “sandwiched” within an item such as a book or magazine. To detect electronic concealment, the number of voxels in a subregion that contains the object having a density above a predetermined threshold is counted and the ratio of that number of voxels to the number of object voxels is computed. If the ratio exceeds a threshold, then it is concluded that the object is concealed in electronics. In response, the CT scanning system can alter discrimination parameters to allow the object to be classified as a threat. For “sandwich” concealment, layers on opposite sides of a sheet object are examined. The mean and standard deviation of density values for the voxels are computed. Where the mean density exceeds a predetermined threshold and the standard deviation is below a different threshold, for at least one of the layers, then it is concluded that the sheet object is sandwiched within an innocuous object such as a magazine or a book.

Title
Apparatus and method for detecting concealed objects in computed tomography data
Application Number
9/228380
Publication Number
6195444 (B1)
Application Date
January 12, 1999
Publication Date
February 27, 2001
Inventor
Carl R Crawford
Brookline
MA, US
Muzzafer Hiraoglu
Woburn
MA, US
Ibrahim M Bechwati
Roslindale
MA, US
Sergey Simanovsky
Lynn
MA, US
Agent
McDermott Will & Emery
US
Assignee
Analogic Corporation
MA, US
IPC
G06K 9/00
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