X-ray scanner

• US 4,756,015 A
• Filed: 06/04/1987
• Issued: 07/05/1988
• Est. Priority Date: 07/14/1986
• Status: Expired due to Fees

• Current Assignee: Heimann GmbH
• Original Assignee: Heimann GmbH
• Inventors: Doenges, Gerhard, Koch, Cornelius
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/057,317
• Time in Patent Office: 397 Days
• Field of Search: 378/99, 378/57, 378/58, 378/146, 250/358.1, 250/359.1, 250/360.1
• US Class Current: 378/57
• CPC Class Codes: G01N 23/04 and forming images of the material
• CPC Class Codes: G01V 5/20 Detecting prohibited goods, e.g. weapons, explosives, hazardous substances, contraband or smuggled objects

Abstract

An x-ray scanner generates a fan-shaped x-ray beam through which an object to be inspected is moved and a detector line which generates signals corresponding to the radiation attenuated by the object. The processing electronics includes a comparator for recognizing faulty detector signals by means of which the roll-in of data ito the image memory is controllable such that, given a faulty detector signal, the transfer of the information into a memory line allocated to the detector is inhibited. The x-ray scanner also includes an allocator unit which omits predetermined detector channels for the purpose of geometric balancing. Given outage of a detector, its detector channel is omitted by the allocator unit, based on a signal from the comparator, instead of a prescribed detector channel.

Claims

1. An x-ray scanner comprising:

an x-ray source which generates a fan-shaped x-ray beam;

a conveyor means for moving an article to be examined through said fan-shaped x-ray beam;

a plurality of detector channels each having a detector which detects radiation attenuated by said article and generates an electronic signal corresponding to the attenuated radiation incident on the detector;

an image memory connected to said detector channels having a respective memory location for each of said detectors respectively in said channels; and

means for controlling entry of data from said detector channels into said image memory by transferring said data from said detector channels into said image memory with transfer from predetermined detector channels being inhibited

comparator means for recognizing one or more of said electronic signals as a faulty detector signal, and upon recognition of a faulty detector signal by said comparator means said means for controlling inhibiting transfer of data from the channel having the faulty detector signal instead of inhibiting one of said pre-determined detector channels.

2. A method for operating an x-ray scanner comprising the steps of:

moving an article to be inspected through a fan-shaped x-ray beam;

detecting the radiation attenuated by said article using a plurality of detectors which generate respective electronic signals as an output in respective detector channels corresponding to the attenuated radiation incident on the respective detectors;

normally transferring data from said detector channels into an image memory with transfer from predetermined detector channels being inhibited to geometrically balance the outputs of said detectors;

identifying one or more of said electronic signals as a faulty detector signal; and

upon the identification of a faulty detector signal, inhibiting transfer of data from the channel having the faulty detector signal instead of inhibiting transfer of data from one of said pre-determined detector channels.

3. An x-ray scanner comprising:

an x-ray source which generates a fan-shaped x-ray beam;

conveyor means for moving an article to be inspected through said fan-shaped x-ray beam;

a plurality of detectors disposed for receiving radiation attenuated by said article, each of said detectors generating an electronic signal as an output in an associated detector channel corresponding to the attenuated radiation incident on the respective detectors;

an analog-to-digital converter connected to each of said detector channels which converts the signals in each of said channels to respective digital signals;

an image memory;

a control unit means for controlling entry of data from each of said channels from the analog-to-digital converter into said image memory, said control unit means including a comparator which recognizes faulty detector signals;

an allocator unit means connected to each of said detector channels and to said control unit means for inhibiting transfer of data from selected channels by said control unit means into said image memory to geometrically balance the outputs of said detectors and, upon identification of a faulty detector signal by said comparator, for inhibiting transfer of data from a channel having said faulty detector signal instead of inhibiting transfer of data from one of said pre-determined detector channels; and

means connected to said image memory for constructing and displaying a visual image of said article from the contents of said image memory.