METHODS AND DEVICES FOR ESTIMATING WEIGHT OF AN OBJECT TO BE INSPECTED IN AN INSPECTION SYSTEM

• US 20170023697A1
• Filed: 07/22/2016
• Published: 01/26/2017
• Est. Priority Date: 07/22/2015
• 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: CHEN, Zhiqiang, LI, Yuanjing, ZHANG, Li, ZHAO, Ziran, LIU, Yaohong, ZHENG, Juan, GU, Jianping, ZONG, Chunguang
• Granted Patent: US 10,379,252 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 weight of an object to be inspected in an inspection system, comprising the steps of:

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 numbers and the high-energy gray value of the dual-energy 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 the area of the pixel.

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

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

3. The method according to claim 1, wherein the mass-thickness attenuation curve is created 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, as the mass-thickness attenuation curve.

4. The method according to claim 1, wherein a 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 information of region of interest selected by a user is received, and weights of pixels within the region of interest are accumulated to acquire weight information for the region of interest.

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

means 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;

means configured to obtain a mass-thickness value for a corresponding pixel 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; and

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

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

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 is acquired from a pre-created mass-thickness attenuation curve by utilizing the grayscale feature values corresponding to the respective pixels; and

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

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

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

9. The method according to claim 7, wherein the mass-thickness attenuation curve is created 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, as the mass-thickness attenuation curve.

10. The method according to claim 7, wherein aluminum is selected as the calibration material blocks to acquire the mass-thickness attenuation curve.

11. The method according to claim 7, wherein information of region of interest selected by a user is received, and weights of pixels within the region of interest are accumulated to acquire weight information for the region of interest.

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

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

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

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