Methods and devices for estimating weight of an object to be inspected in an inspection system

• US 10,379,252 B2
• Filed: 07/22/2016
• Issued: 08/13/2019
• Est. Priority Date: 07/22/2015
• Status: Active Grant

• Current Assignee: Nuctech Company Limited (Tsinghua Tongfang Co., Ltd.), Tsinghua University
• Original Assignee: Tsinghua University
• Inventors: Chen, Zhiqiang, Li, Yuanjing, Zhang, Li, Zhao, Ziran, Liu, Yaohong, Zheng, Juan, Gu, Jianping, Zong, Chunguang
• Primary Examiner(s): Ho, Allen C.
• Application Number:
  US15/217,787
• Publication Number:
  US 20170023697A1
• Time in Patent Office: 1,117 Days
• Field of Search: 378 5, 378 16, 378 51, 378 53- 57, 378 989, 378 9811, 378207
• CPC Class Codes: G01N 23/04 and forming images of the material
• CPC Class Codes: G01N 23/046 using tomography, e.g. computed tomography [CT]
• CPC Class Codes: G01N 23/083 the radiation being X-rays
• CPC Class Codes: G01N 23/087 using polyenergetic X-rays
• CPC Class Codes: G01V 5/12 using gamma or X-ray sources gamma sources using isotopes G21G4/00; X-ray tubes H01J35/00
• 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 5/224 Multiple energy techniques using one type of radiation, e.g. X-rays of different energies
• CPC Class Codes: G01V 5/226 using tomography

Abstract

Disclosed is a method and device for estimating weight of an object to be inspected in an inspection system. An effective atomic number and a high-energy gray value of the dual-energy corresponding to each pixel of the object to be inspected are obtained by a dual-energy radiation scanning. A mass-thickness value for a corresponding pixel is obtained from a pre-created mass-thickness attenuation curve by utilizing the effective atomic numbers and the high-energy gray value of the dual-energy for respective pixels. Weight information for at least a part of the object to be inspected is calculated by multiplying the mass-thickness value by the area of the pixel. Such a method may accurately calculate the weight of the object to be inspected and save the cost for a conventional weighing hardware.

Claims

1. A method for estimating a weight of an object to be inspected in an inspection system, comprising:

obtaining an effective atomic number and a dual-energy high-energy grayscale feature value corresponding to each pixel of the object to be inspected by a dual-energy radiation scanning;

obtaining a mass-thickness value for a corresponding pixel from a pre-created mass-thickness attenuation curve by utilizing the effective atomic number and the dual-energy high-energy grayscale feature value for respective pixels; and

calculating weight information for at least a part of the object to be inspected by multiplying the mass-thickness value by an area of the pixel.

2. The method according to claim 1, further comprising:

estimating a physical dimension corresponding to each pixel on an image of the object to be inspected in a direction in which detectors are arranged, based on a pitch between detector pixels, a distance between an X-ray source and the detectors, and a distance between the X-ray source and the object to be inspected;

obtaining a pixel physical dimension in a scanning direction based on a scanning speed and an acquiring frequency of the detectors; and

obtaining an area of each pixel by multiplying the physical dimension in the direction in which the detectors are arranged by the pixel physical dimension in the scanning direction.

3. The method according to claim 1, further comprising creating the pre-created mass-thickness attenuation curve by:

utilizing different types of calibration material blocks with known thicknesses to acquire a relationship curve among an X-ray attenuation coefficient, the effective atomic number, and the mass-thickness value, as the pre-created mass-thickness attenuation curve.

4. The method according to claim 1, wherein the obtaining a mass-thickness value for a corresponding pixel comprises acquiring the mass-thickness value corresponding to both of the effective atomic number and dual-energy high-energy grayscale feature value is acquired by linear interpolation.

5. The method according to claim 1, wherein the calculating weight information for at least a part of the object to be inspected comprises acquiring the weight information for a region of interest by accumulating weights of pixels within the region of interest when information of the region of interest selected by a user is received.

6. A device for estimating a weight of an object to be inspected in an inspection system, the device comprising:

one or more processors; and

a memory connected to the one or more processors and having one or more programs stored therein, which, when executed by the one or more processors, cause the one or more processors to be configured to;

obtain an effective atomic number and a dual-energy high-energy grayscale feature value corresponding to each pixel of the object to be inspected by a dual-energy radiation scanning;

obtain a mass-thickness value for a corresponding pixel from a pre-created mass-thickness attenuation curve by utilizing the effective atomic number and the dual-energy high-energy grayscale feature value for respective pixels; and

calculate weight information for at least a part of the object to be inspected by multiplying the mass-thickness value by an area of the pixel.

7. A method for estimating a weight of an object to be inspected in an inspection system, the method comprising:

obtaining a grayscale feature value corresponding to each pixel of an object to be inspected by a single-energy radiation scanning;

obtaining a mass-thickness value for a corresponding pixel from a pre-created mass-thickness attenuation curve by utilizing the grayscale feature value corresponding to respective pixels; and

calculating weight information for at least a part of the object to be inspected by multiplying the mass-thickness value by an area of the pixel.

8. The method according to claim 7, further comprising:

estimating a physical dimension corresponding to each pixel on an image of the object to be inspected in a direction in which detectors are arranged, based on a pitch between detector pixels, a distance between a X-ray source and the detectors, and a distance between the X-ray source and the object to be inspected;

obtaining a pixel physical dimension in a scanning direction based on a scanning speed and an acquiring frequency of the detectors; and

obtaining an area of each pixel by multiplying the physical dimension in the direction in which the detectors are arranged by the pixel physical dimension in the scanning direction.

9. The method according to claim 7, further comprising creating the pre-created mass-thickness attenuation curve by:

utilizing a calibration material block with a known thickness to acquire a relationship curve among an X-ray attenuation coefficient and the mass-thickness value, as the pre-created mass-thickness attenuation curve.

10. The method according to claim 7, further comprising selecting aluminum as a calibration material block to acquire the pre-created mass-thickness attenuation curve.

11. The method according to claim 7, wherein the calculating weight information for at least a part of the object to be inspected comprises acquiring the weight information for a region of interest by accumulating weights of pixels within the region of interest when information of the region of interest selected by a user is received.

12. A device for estimating a weight of an object to be inspected in an inspection system, the device comprising:

one or more processors; and

a memory connected to the one or more processors and having one or more programs stored therein, which, when executed by the one or more processors, cause the one or more processors to be configured to;

obtain a grayscale feature value corresponding to each pixel of an object to be inspected by a single-energy radiation scanning;

obtain a mass-thickness value for a corresponding pixel from a pre-created mass-thickness attenuation curve by utilizing the grayscale feature value corresponding to respective pixels; and

calculate weight information for at least a part of the object to be inspected by multiplying the mass-thickness value by an area of the pixel.