US-12626484-B2 - Apparatus and method for identifying and displaying material types using multi-energy X-ray backscattering

US12626484B2US 12626484 B2US12626484 B2US 12626484B2US-12626484-B2

Abstract

Proposed is an apparatus and method for identifying and displaying material types using multi-energy X-ray backscattering. Specifically, the method for identifying cargo includes a process of installing a phantom having a preset location and material, a process of performing photographing under a condition of orthogonal incidence on another side of the predefined container walls, a process of normalizing an entire image, a process of generating a difference image from the normalized multi-energy backscattering image, a process of inferring a similarity with a target material, a process of detecting a location and type of the target material in the entire image, and a process of transmitting information on the location and type of the target material to a display.

Inventors

Ji Wook Jeong

Assignees

ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE

Dates

Publication Date: 20260512
Application Date: 20240514
Priority Date: 20230919

Claims (20)

1 . An operating method for identifying cargo in a container, the method comprising: a process of installing a phantom having a preset location and a material on one side of predefined container walls; a process of performing photographing under a condition of orthogonal incidence on another side of the predefined container walls by a multi-energy X-ray disposed on the one side; a process of normalizing an entire image from a result of performing photographing; a process of generating a difference image from the normalized multi-energy backscattering image; a process of inferring a similarity with a target material from the result of performing photographing; a process of detecting a location and type of the target material in the entire image on the basis of the difference image and the inferred similarity; and a process of transmitting information on the location and type of the target material to a display.
2 . The method of claim 1 , wherein the result of performing photographing is multi-energy photographing data for each constructed target material.
3 . The method of claim 1 , wherein the process of performing photographing comprises a process of removing a noise generated when performing photographing.
4 . The method of claim 1 , wherein the phantom has a form where a plurality of samples of materials having the same thickness are arranged in a plane perpendicular to a source-detector axis without overlapping each other.
5 . The method of claim 4 , wherein the plurality of materials comprise various materials that reflect actual loading statistics about various metals or organic materials utilized as container materials.
6 . The method of claim 1 , wherein the phantom is installed so as not to overlap a container area and is installed on the one side of the container walls at a predetermined location under a condition that a loaded cargo is not overlapped during normal backscattering photographing.
7 . The method of claim 1 , wherein the process of performing photographing comprises a process of calibrating a loaded container image on the basis of an empty container image, wherein the calibrating process comprises a process of identifying the empty container image photographed with a wavelength that matches or is similar to the loaded container image; a process of automatically or manually identifying a placement of the phantom so as not to overlap a container area when photographing the loaded container image; a process of determining a color tone conversion formula through a linear or non-linear regression so that the loaded container image and the identified empty container image have statistically the same brightness distribution; and a process of applying the color tone conversion formula to the entire image for conversion.
8 . The method of claim 7 , wherein the process of determining the color tone conversion formula comprises a process of inferring and reconstructing a new empty container image according to the loaded container image condition from images of two or more adjacent conditions using the linear or nonlinear regression method when a geometric condition, wavelength, and spatial resolution between the loaded container image and the empty container image do not exactly match.
9 . The method of claim 1 , wherein the process of inferring the similarity with the target material from the result of performing photographing comprises a process of calculating a similarity between a pixel value of the difference image constructed for a multi-energy backscattering photographing image photographed for the container and the photographed data of an energy corresponding to the constructed target material, and a process of identifying the target material by comparing an average similarity value within an area of interest with a pre-determined threshold value.
10 . The method of claim 1 , wherein the process of applying the color tone conversion formula to the entire image for conversion comprises a process of identifying a plurality of energy bands in which the target material detection performance is optimized wherein the backscattering characteristics between target materials are most contrasted from multi-energy photographing data for each constructed target material, and a process of generating a difference image by generating each pixel value on the basis of a difference in backscattering characteristic parameter values between the plurality of energy bands.
11 . An apparatus for identifying cargo in a container, the apparatus comprising: a memory; a transceiver; and a controller operably connected to the memory and the transceiver; wherein the controller is capable of installing a phantom having a preset location and a material on one side of predefined container walls, performing photographing under a condition of orthogonal incidence on another side of the predefined container walls by a multi-energy X-ray disposed on the one side, normalizing an entire image from a result of performing photographing, generating a difference image from the normalized multi-energy backscattering image, inferring a similarity with a target material from the result of performing photographing, detecting a location and type of the target material in the entire image on the basis of the difference image and the inferred similarity, and transmitting information on the location and type of the target material to a display.
12 . The apparatus of claim 11 , wherein the result of the performing photographing is multi-energy photographing data for each constructed target material.
13 . The apparatus of claim 11 , wherein the controller removes a noise generated when performing photographing in order to perform photographing.
14 . The apparatus of claim 11 , wherein the phantom has a form where a plurality of samples of materials having the same thickness are arranged in a plane perpendicular to a source-detector axis without overlapping each other.
15 . The apparatus of claim 14 , wherein the plurality of materials comprise various materials that reflect actual loading statistics about various metals or organic materials utilized as container materials.
16 . The apparatus of claim 11 , wherein the phantom is installed so as not to overlap a container area and is installed on one side of container walls at a predetermined location under a condition that a loaded cargo is not overlapped during normal backscattering photographing.
17 . The apparatus of claim 11 , wherein the controller infers and reconstructs a new empty container image according to a loaded container image conditions from images of two or more adjacent conditions using a linear or nonlinear regression method in order to determine the color tone conversion formula when a geometric condition, wavelength, and spatial resolution between the loaded container image and the empty container image do not exactly match.
18 . The apparatus of claim 11 , wherein the controller calculates a similarity between a pixel value of the difference image constructed for a multi-energy backscattering photographing image photographed for the container and a photographed data of an energy corresponding to the constructed target material, and identifies the target material by comparing an average similarity value within an area of interest with a pre-determined threshold value, in order to infer the similarity with the target material from the result of performing photographing.
19 . The apparatus of claim 11 , wherein the controller identifies a plurality of energy bands in which the target material detection performance is optimized wherein the backscattering characteristics between target materials are most contrasted from multi-energy photographing data for each constructed target material, and generates a difference image by generating each pixel value on the basis of a difference in a backscattering characteristic parameter value between the plurality of energy bands in order to apply the color tone conversion formula to the entire image for conversion.
20 . A non-transitory computer-readable storage medium for storing one or more programs comprising instructions, wherein the instructions, when executed by an apparatus for detecting cargo in a container, enable the apparatus to install a phantom having a preset location and a material on one side of predefined container walls, to perform photographing under a condition of orthogonal incidence on another side of the predefined container walls by a multi-energy X-ray disposed on the one side, to normalize an entire image from a result of performing photographing, to generate a difference image from the normalized multi-energy backscattering image, to infer a similarity with a target material from the result of performing photographing, to detect a location and type of the target material in the entire image on the basis of the difference image and the inferred similarity, and to transmit information on the location and type of the target material to a display.

Description

CROSS REFERENCE TO RELATED APPLICATION The present application claims priority to Korean Patent Application No. 10-2023-0124968, filed on Sep. 19, 2023, the entire contents of which are incorporated herein for all purposes by this reference. BACKGROUND Technical Field The present disclosure generally relates to an imaging apparatus and, more specifically, to an apparatus and method for identifying and displaying a material type using multi-energy X-ray backscattering. Description of the Related Art The X-ray transmission image, which is commonly used to screen baggage and cargo for dangerous goods, may be taken in a situation where various loads are distributed in multiple layers in a container, for example, in the case of a container X-ray transmission image. A method using X-ray transmission is suitable for identifying and detecting dangerous goods made of metal materials. Meanwhile, in the case of an organic material having a lower X-ray absorption than a metal due to the transmission attenuation characteristics, it is not easy to detect since it is not well revealed when there is overlapped metal cargo around. For such a reason, X-ray backscattering imaging technologies have been widely studied and utilized in recent years because it is possible to obtain detection images generated in a way that directly reflects the surface of an object while being relatively easy to detect by collecting material distribution information relatively close to two-dimension through collecting signals that return as backscattering from cargo distributed at a relatively certain distance within a limited space from the X-ray source using X-ray backscattering images. In particular, in the case of a security screening imaging device such as ZBV, it has been mainly used to detect concealed cargo after moving and installing next to a cargo container while being mounted on a vehicle through obtaining backscattering images by radiating low-dose X-rays toward the side of a container and then by imaging X-ray backscattering signals that are reflected and returned. In this case, the signals reflected from the container wall are mixed with the signals reflected from the cargo during backscattering since most walls of the containers where cargo are loaded are made of metal, thereby making it difficult to detect with the naked eye, and even more difficult when an object to be detected is an organic material. SUMMARY On the basis of the above discussion, the present disclosure provides an apparatus and method for identifying and displaying a material type using multi-energy X-ray backscattering. In addition, the present disclosure provides an apparatus and method for identifying cargo (material) inside a container by normalizing a container image by using a phantom. In addition, the present disclosure provides an apparatus and method for detecting or uncovering a type of cargo loaded within a container. In addition, the present disclosure provides an apparatus and method for identifying a type of target material within a container by using multi-energy backscattering characteristics of the target material in the container. According to a variety of exemplary embodiments of the present disclosure, an operating method for identifying cargo in a container includes a process of installing a phantom having a preset location and material on one side of predefined container walls, a process of performing photographing under a condition of orthogonal incidence on another side of the predefined container walls by a multi-energy X-ray disposed on the one side, a process of normalizing an entire image from the result of performing photographing, a process of generating a difference image from the normalized multi-energy backscattering image, a process of inferring a similarity with a target material from the result of performing photographing, a process of detecting a location and type of the target material in the entire image on the basis of the difference image and the inferred similarity, and a process of transmitting information on the location and type of the target material to a display. According to a variety of exemplary embodiments of the present disclosure, an apparatus for identifying cargo in a container includes a memory, a transceiver, and a controller operably connected to the memory and the transceiver, wherein the controller is capable of installing a phantom having a preset location and material on one side of predefined container walls, performing photographing under a condition of orthogonal incidence on another side of the predefined container walls by a multi-energy X-ray disposed on the one side, normalizing an entire image from the result of performing photographing, generating a difference image from the normalized multi-energy backscattering image, inferring a similarity with a target material from the result of performing photographing, detecting a location and type of the target material in the entire image on the basis