Transmission enhanced scatter imaging

• US 6,546,072 B1
• Filed: 07/24/2000
• Issued: 04/08/2003
• Est. Priority Date: 07/30/1999
• Status: Expired due to Term

• Current Assignee: American Science and Engineering Incorporated (OSI Systems Incorporated)
• Original Assignee: American Science and Engineering Incorporated (OSI Systems Incorporated)
• Inventors: Chalmers, Alexander
• Primary Examiner(s): Kim, Robert H.
• Assistant Examiner(s): KAO, CHIH CHENG G
• Application Number:
  US09/624,450
• Time in Patent Office: 988 Days
• Field of Search: 378/57, 378/70, 378/86, 378/87, 378/51, 378/62, 378/63, 250/358.1, 250/393
• US Class Current: 378/57
• CPC Class Codes: G01V 5/22 Active interrogation, i.e. by irradiating objects or goods using external radiation sources, e.g. using gamma rays or cosmic rays
• CPC Class Codes: G01V 5/222 measuring scattered radiation

Abstract

An apparatus and method for enhancing an image of penetrating radiation scattered by objects concealed within a container. An image derived from penetrating radiation transmitted through the container is combined with a scatter image in regard to which it is accurately registered in such a manner as to provide enhanced visibility and photorealism of the combined image.

Claims

1. A method for displaying an image of contents of a container, the method comprising:

a. illuminating the container with at least one beam of penetrating radiation;

b. detecting radiation scattered from the beam of penetrating radiation by the contents of the container for forming a scatter image of the contents of the container, the scatter image characterized by a plurality of scatter pixels;

c. detecting radiation from the beam of penetrating radiation transmitted through the contents of the container for forming a transmission image of the contents of the container, the transmission image having a transmission pixel corresponding to each scatter pixel of the scatter image;

d. forming a combination image having pixels, such that a value is associated with each pixel, the value corresponding to a specified combination of a value associated with each scatter pixel of the plurality of scatter pixels and a value associated with the transmission pixel corresponding to the scatter pixel; and

e. displaying the combination image on a display device, wherein the specified combination of each scatter pixel and the transmission pixel corresponding to the scatter pixel is a linear combination of a function of the value associated with the scatter pixel and a function of the value associated with the transmission pixel.

2. A method according to claim 1, wherein the specified combination of each scatter pixel and the transmission pixel corresponding to the scatter pixel is a linear combination of a quadratic function of the value associated with the scatter pixel and a quadratic function of the value associated with the transmission pixel.

3. A method according to claim 1, wherein the value associated with each scatter pixel is a logarithmic function of an intensity of scattered radiation detected at the scatter pixel.

4. A method according to claim 1, wherein the value associated with each transmission pixel is a logarithmic function of an intensity of transmitted radiation detected at the transmission pixel.

7. A method according to claim 1, wherein the beam of penetrating radiation is a beam of x-rays.

5. An apparatus for displaying an image of contents of a container, the apparatus comprising:

a. a source of penetrating radiation for illuminating the container with at least one beam of penetrating radiation;

b. a first detector arrangement for detecting radiation scattered from the beam of penetrating radiation by the contents of the container and for forming a scatter image of the contents of the container, the scatter image characterized by a plurality of scatter pixels;

c. a second detector arrangement for detecting radiation from the beam of penetrating radiation transmitted through the contents of the container for forming a transmission image of the contents of the container, the transmission image having a transmission pixel corresponding to each scatter pixel of the scatter image;

d. a processor for combining the transmission image and the scatter image to form a combination image having pixels, such that a value is associated with each pixel, the value corresponding to a specified combination of a value associated with each scatter pixel of the plurality of scatter pixels and a value associated with the transmission pixel corresponding to the scatter pixel; and

e. a display device for displaying the combination image,

wherein the specified combination of each scatter pixel and the transmission pixel corresponding to the scatter pixel is a linear combination of a function of the value associated with the scatter pixel and a function of the value associated with the transmission pixel.

6. An apparatus in accordance with claim 5, further comprising a user input interface such that a user may vary the specified combination of the value associated with each scatter pixel of the plurality of scatter pixels and the value associated with the transmission pixel corresponding to the scatter pixel.

8. An apparatus according to claim 5, wherein the beam of penetrating radiation is a beam of x-rays.