Human body back scattering inspection method and system

• US 9,651,507 B2
• Filed: 12/16/2014
• Issued: 05/16/2017
• Est. Priority Date: 02/24/2014
• Status: Active Grant

• Current Assignee: Nuctech Company Limited (Tsinghua Tongfang Co., Ltd.), Tsinghua University
• Original Assignee: Nuctech Company Limited (Tsinghua Tongfang Co., Ltd.), Tsinghua University
• Inventors: Jin, Yingkang, Chen, Zhiqiang, Zhao, Ziran, Li, Yuanjing, Zhang, Li, Zhu, Chenguang, Wu, Wanlong, Tang, Le, Ruan, Ming, Ding, Xianli
• Primary Examiner(s): Song, Hoon
• Application Number:
  US14/572,528
• Publication Number:
  US 20150241368A1
• Time in Patent Office: 882 Days
• CPC Class Codes: G01N 23/203 Measuring back scattering
• CPC Class Codes: G01T 1/167 Measuring radioactive content of objects, e.g. contamination whole body counters G01T1/163
• CPC Class Codes: G01V 5/222 measuring scattered radiation
• CPC Class Codes: G01V 5/281 detecting special nuclear material [SNM], e.g. Uranium-235, Uranium-233 or Plutonium-239

Abstract

A human body back-scattering inspection method and system are discloses. The method includes: obtaining a back-scattering scan image of a human body under inspection; distinguishing a body image from a background image in the back-scattering scan image; and calculating a feature parameter of the background image to determine whether radioactive substance is carried with the human body. With some embodiments of the present disclosure, it is possible to determine whether any radioactive substance is carried with a human body during back-scattering inspection of the human body. In further embodiments of the present disclosure, it is possible to approximately determine which part(s) of the human body carries the radioactive substance. This improves efficiency of inspection.

Claims

1. A human body back-scattering inspection method comprising:

obtaining a back-scattering scan image of a human body under inspection;

distinguishing a body image from a background image in the back-scattering scan image; and

calculating a feature parameter of the background image to determine whether a radioactive substance is carried with the human body;

wherein the calculating of the feature parameter of the background image to determine whether the radioactive substance is carried with the human body comprises;

calculating an average luminance value of pixels in the background image; and

determining that the radioactive substance is carried with the human body if the average luminance value is larger than a preset value.

2. The human body back-scattering inspection method according to claim 1, wherein the step of calculating an average luminance value of pixels in the background image comprises:

integrating luminance data of the background image, and calculating an average of luminance values of the pixels as the average luminance value.

3. The human body back-scattering inspection method according to claim 2, wherein it is determined that radioactive substance is carried with the human body if the average luminance value is larger than N_0k+n×

σ

_k, wherein N_0k represents a mean value of background luminance, σ

_k represents a variance of fluctuations in N_0k for a time period, n represents a variance multiplication coefficient, and k represents the number of pixels in the background image.

4. The human body back-scattering inspection method according to claim 1, further comprising:

dividing the background image into a plurality of parts;

calculating an average luminance value of pixels in each of the parts; and

determining that the radioactive substance is hidden in a part of the body corresponding to the part of the background image having the largest average luminance value.

5. The human body back-scattering inspection method according to claim 1, wherein a back-scattering detector comprising a plurality of detector modules is used to scan the human body, and the method further comprises:

calculating an average luminance value for each of the detector modules; and

determining the radioactive substance is hidden in a part of the body corresponding to the detector module having the largest average luminance value.

6. The human body back-scattering inspection method according to claim 1, further comprising:

dividing the background image into a plurality of parts;

calculating an average luminance value of pixels in each of the parts; and

determining that the radioactive substance is hidden in parts of the body corresponding to the parts of the background image each having an average luminance value larger than the preset value.

7. The human body back-scattering inspection method according to claim 1, wherein a back-scattering detector comprising a plurality of detector modules is used to scan the human body, and the method further comprises:

calculating an average luminance value for each of the detector modules; and

determining the radioactive substance is hidden in parts of the body corresponding to the detector modules each having the average luminance value larger than the preset value.

8. A human body back-scattering inspection system comprising:

a ray generator configured to generate a ray beam;

a flying-spot forming device configured to modulate the ray beam and form a flying-spot ray beam;

a back-scattering detector configured to receive a scattered ray generated by irradiating the flying-spot ray beam onto the human body, and generate an electric signal; and

a control and data processing terminal configured to obtain a back-scattering scan image of the human body based on the electric signal, distinguish a body image from a background image in the back-scattering scan image, and calculate a feature parameter of the background image to determine whether radioactive substance is carried with the human body;

wherein the control and data processing terminal calculates an average luminance value of pixels in the background image, and determines that the radioactive substance is carried with the human body if the average luminance value is larger than a preset value.

9. The human body back-scattering inspection system according to claim 8, wherein the control and data processing terminal integrates luminance data of the background image, and calculate an average of luminance values of the pixels as the average luminance value.

10. The human body back-scattering inspection system according to claim 9, wherein the control and data processing terminal determines that radioactive substance is carried with the human body if the average luminance value is larger than N_0k+n×

σ

_k, wherein N_0k represents a mean value of background luminance, σ

_k represents a variance of fluctuations in N_0k for a time period, n represents a variance multiplication coefficient, and k represents the number of pixels in the background image.

11. The human body back-scattering inspection system according to claim 8, wherein the control and data processing terminal divides the background image into a plurality of parts, calculates an average luminance value of pixels in each of the parts, and determines that the radioactive substance is hidden in a part of the body corresponding to the part of the background image having the largest average luminance value.

12. The human body back-scattering inspection system according to claim 8, wherein the back-scattering detector comprises a plurality of detector modules, and

the control and data processing terminal calculates an average luminance value for each of the detector modules, and determines the radioactive substance is hidden in a part of the body corresponding to the detector module having the largest average luminance value.

13. The human body back-scattering inspection system according to claim 8, wherein the control and data processing terminal divides the background image into a plurality of parts, calculates an average luminance value of pixels in each of the parts, and determines that the radioactive substance is hidden in parts of the body corresponding to the parts of the background image each having an average luminance value larger than the preset value.

14. The human body back-scattering inspection system according to claim 8, wherein the back-scattering detector comprises a plurality of detector modules, and

the control and data processing terminal calculates an average luminance value for each of the detector modules, and determines the radioactive substance is hidden in parts of the body corresponding to the detector modules each having the average luminance value larger than the preset value.