CN109142404B - Back-scattering imaging system, scanning inspection system and back-scattering image imaging method - Google Patents
Back-scattering imaging system, scanning inspection system and back-scattering image imaging method Download PDFInfo
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- CN109142404B CN109142404B CN201811291946.2A CN201811291946A CN109142404B CN 109142404 B CN109142404 B CN 109142404B CN 201811291946 A CN201811291946 A CN 201811291946A CN 109142404 B CN109142404 B CN 109142404B
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Abstract
The invention discloses a back scattering imaging system, a scanning inspection system and a back scattering image imaging method. The backscatter imaging system includes: a back-scatter source arranged to have a first scanning state in which no scanning beam is emitted and a second scanning state in which a scanning beam is emitted when scanning is performed; the back scattering detector detects a first back scattering signal when a back scattering line source of the back scattering imaging system is in a first scanning state, and detects a second back scattering signal when the back scattering line source is in a second scanning state; a control device in signal connection with the backscatter detector, configured to modify the second backscatter signal with a modification signal formed from the first backscatter signal to obtain a modified backscatter signal, and to form graphical information from the modified backscatter signal; and the imaging device is in signal connection with the control device and generates a back scattering image in a second scanning state according to the graphic information. The back scattering image obtained by the invention is clearer.
Description
Technical Field
The invention relates to the technical field of radiation inspection, in particular to a back scattering imaging system, a scanning inspection system and a back scattering image imaging method.
Background
Existing scanning inspection systems can be classified into transmission inspection systems using transmission imaging techniques and backscatter inspection systems using backscatter imaging techniques from the imaging principle perspective.
The transmission inspection system forms a transmission image, the transmission image is formed by detecting rays through a detector positioned at the other side of the object after the rays are attenuated by the object, and the transmission signals of the rays reflect the information such as the density, the thickness and the like of the inspected object and can display the internal structure of the object. The transmission inspection system has the advantages of strong ray transmission and good image quality.
The backscatter inspection system utilizes the compton scattering effect to form a scatter image by capturing photon images reflected from the subject. The scattering image is formed by a ray signal scattered by an object of a certain depth in the direction of the object approaching the detector. Due to the stronger compton scattering of radiation in low atomic number materials such as explosives, drugs, and the like, the backscatter inspection system can resolve materials and highlight organic materials.
It can be seen that a transmission inspection system utilizing transmission imaging techniques and a backscatter inspection system utilizing backscatter imaging techniques each have advantages in inspecting containers (e.g., container boxes, cargo compartments of vehicles, etc.). A scanning inspection system that integrates transmission imaging technology and backscatter imaging technology may include both transmission imaging system and backscatter imaging system, combining the advantages of both, but with interference between the transmission imaging system and the backscatter imaging system. The back scattering line source dosage of the back scattering imaging system is low, so that the back scattering imaging system can not interfere with the transmission image; while the higher dose of the transmission radiation source of a typical transmission imaging system can interfere with the back-scattered image.
The reason why the transmitted rays generated by the transmitted ray source interfere with the back-scattered image will be described below with reference to fig. 1 and 2.
The transmission imaging system and the back scattering imaging system in the scanning inspection system can be imaging systems with vertical visual angles, can be imaging systems with horizontal visual angles, can also comprise imaging systems with vertical visual angles and imaging systems with horizontal visual angles, and the like. FIG. 1 is a schematic diagram of the interference of a back-scattered image when the transmission imaging system and the back-scattered imaging system of a scanning inspection system are imaging systems of vertical view. Fig. 2 is a schematic diagram of the interference of the back-scattered image when the transmission imaging system and the back-scattered imaging system of the scanning inspection system are imaging systems with horizontal viewing angles.
In fig. 1 and 2, a transmission ray emitted from a transmission ray source penetrates through an object to be detected and is received by a transmission detector, and a back scattering signal received by the transmission detector is converted into a transmission image of the object to be detected; the rays emitted by the back-scattering line source are reflected by the object to be detected and then received by the back-scattering detector, and the back-scattering signals received by the back-scattering detector are converted into back-scattering images of the object to be detected. However, during the scanning process, the scattered radiation formed after the transmitted radiation irradiates the ground (as shown in fig. 1) or the object to be detected (as shown in fig. 2) can also be received by the back scatter detector, so that interference is caused to the back scatter image. In the figures 1 and 2 of the drawings,Representing scattered rays received by a back-scattered detector after the scattered rays are irradiated on the ground, wherein the scattered rays are interference signals of a back-scattered image; The scattered radiation received by the back scatter detector after being scattered by the back scatter source is an effective signal of a back scatter image. The interference caused by the back-scattered rays formed after irradiating on different object surfaces on the back-scattered images is not uniform, and even the interference caused by the transmitted rays when irradiating on different positions of the object to be detected in the scanning process is not uniform.
Disclosure of Invention
The invention aims to provide a back scattering imaging system, a scanning inspection system and a back scattering image imaging method.
A first aspect of the invention provides a backscatter imaging system comprising:
a back-scatter source arranged to have a first scanning state in which no scanning beam is emitted and a second scanning state in which a scanning beam is emitted when scanning is performed;
A backscatter detector that detects a first backscatter signal when a backscatter source of the backscatter imaging system is in the first scanning state and detects a second backscatter signal when the backscatter source is in the second scanning state;
Control means, in signal communication with said backscatter detectors, arranged to modify said second backscatter signal with a modification signal formed from said first backscatter signal to obtain a modified backscatter signal and to form graphical information from said modified backscatter signal; and
And the imaging device is in signal connection with the control device and generates a back scattering image in the second scanning state according to the graphic information.
In some embodiments, the back-scatter source is configured to have a ratio of 1% to 51% of the time in the first scanning state to the sum of the times in the first scanning state and the second scanning state.
In some embodiments, the back-scatter source comprises a radiation source and a flying spot device, wherein the flying spot device comprises a flywheel provided with a beam aperture and a fan-shaped box provided with a collimation slit, or the flying spot device comprises a rotating drum provided with a collimation slit.
In some embodiments, the backscatter imaging system includes a speed sensor for measuring a relative speed of movement of the subject and the backscatter imaging system to form a speed signal, and the control device is in signal communication with the speed sensor and corrects the second backscatter signal to form the corrected backscatter signal based on the speed signal and the first backscatter signal.
In some embodiments, the backscatter sources are arranged to have the first scan state when each column of scans is performed or the first scan state when more than two columns of scans are performed consecutively.
A second aspect of the invention provides a scanning inspection system comprising a backscatter imaging system according to any one of the first aspects of the invention.
In some embodiments, the scanning inspection system further comprises a transmission inspection system.
A third aspect of the present invention provides a back-scattered image imaging method of a back-scattered imaging system, comprising:
A back scatter detector of the back scatter imaging system detects a first back scatter signal in a first scanning state without a scanning light beam emitted when a back scatter line source of the back scatter imaging system performs scanning;
The back scatter detector detects a second back scatter signal in a second scanning state of emitting a scanning beam when the back scatter source performs scanning;
modifying the second backscatter signal with a modification signal formed from the first backscatter signal to obtain a modified backscatter signal, and forming graphical information from the modified backscatter signal;
and generating a back scattering image in the second scanning state according to the graphic information.
In some embodiments, modifying the second backscatter signal with a modification signal formed from the first backscatter signal to obtain a modified backscatter signal includes forming the modified backscatter signal by subtracting a product of the modification signal and a modification coefficient from the second backscatter signal.
In some embodiments, the correction factor ranges from 0.8 to 1.2.
In some embodiments, the second back-scattered signal when performing a column scan is corrected with one of the first back-scattered signals in the first scan state when the back-scattered line source performs each column scan or with a mean value of two or more of the first back-scattered signals in the first scan state when the back-scattered line source performs each column scan as the correction signal.
In some embodiments, the correction signal is a mean value of one of the first backscatter signals in the first scanning state when the backscatter source continuously performs two or more columns of scanning or the second backscatter signal when the two or more columns of scanning are performed when the backscatter source continuously performs two or more columns of scanning.
In some embodiments, the second back-scattered signal when the two or more scans are performed is corrected with the mean value of the two or more first back-scattered signals in the first scanning state of the same column of scans as the correction signal; or correcting the second back-scattered signal when the two or more columns of scanning are performed with the average value of the two or more first back-scattered signals in the first scanning state of at least two columns of scanning as the correction signal.
In some embodiments, two or more of the first backscatter signals are selected in the first scanning state of each column of scanning, and the second backscatter signals when the two or more columns of scanning are performed are corrected by using the average value of all the selected first backscatter signals as the correction signal.
In some embodiments, comprising:
Measuring the relative movement speed of the object to be detected and the back scattering imaging system to form a speed signal;
and correcting the second back scattering signal according to the speed signal and the correction signal formed by the first back scattering signal to form the correction back scattering signal.
In some embodiments, the speed signal indicates that when the relative movement speed is greater than a predetermined relative movement speed, the second backscatter signals when two or more of the first backscatter signals in the first scanning state of the same column of scanning are corrected with the mean value of the two or more of the first backscatter signals as a correction signal; the speed signal indicates that when the relative movement speed is less than or equal to the predetermined relative movement speed, the second backscatter signals when two or more of the scans are performed are corrected with an average value of the two or more of the first backscatter signals in the first scanning state of at least two of the scans as a correction signal.
Based on the back scattering imaging system, the scanning inspection system and the back scattering image imaging method provided by the invention, the first back scattering signal is a back scattering signal measured when the back scattering line source does not emit scanning light beams, the first back scattering signal can be regarded as an interference signal generated when the back scattering imaging system is inspected by surrounding interference rays, the second back scattering signal can be regarded as a composite signal of an effective signal formed by mixing the reflected light emitted by the back scattering line source after scanning light emitted by the object to be inspected and the surrounding interference rays, the second back scattering signal is corrected by using a correction signal formed according to the first back scattering signal to form a corrected back scattering signal, and the back scattering image in a second scanning state is formed on the basis of the correction signal, so that the influence of the interference signal can be at least partially removed on the basis of the composite signal, thereby enabling the obtained back scattering image to be clearer.
Other features of the present invention and its advantages will become apparent from the following detailed description of exemplary embodiments of the invention, which proceeds with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute a limitation on the application. In the drawings:
FIG. 1 is a schematic diagram of the interference of a back-scattered image when the transmission imaging system and the back-scattered imaging system of a scanning inspection system are imaging systems of vertical view.
Fig. 2 is a schematic diagram of the interference of the back-scattered image when the transmission imaging system and the back-scattered imaging system of the scanning inspection system are imaging systems with horizontal viewing angles.
Fig. 3 is a schematic plan view of the principle of a back-scatter source in a back-scatter imaging system of a scanning inspection system.
Fig. 4 is a schematic perspective view of the principle of a back-scatter source in a back-scatter imaging system of a scanning inspection system.
FIG. 5 is a back-scattered image of a back-scattered imaging system of a scanning inspection system not disturbed by scattered radiation formed by transmitted radiation of the transmission imaging system.
FIG. 6 is a non-interference-free back-scattered image produced when a back-scattered imaging system of a scanning inspection system is interfered with scattered radiation formed by transmitted radiation of the transmission imaging system.
FIG. 7 is a back-scattered image of a scan inspection system with the back-scattered image being removed by a back-scattered image imaging method of an embodiment of the invention when the back-scattered imaging system is disturbed by scattered radiation formed by transmitted radiation from the transmission imaging system.
FIG. 8 is a back-scattered image of a scan inspection system with the back-scattered image being removed by another embodiment of the invention when the back-scattered image system is disturbed by scattered radiation formed by transmitted radiation from the transmission imaging system.
FIG. 9 is a back-scattered image of a scan inspection system with the back-scattered image being removed by a back-scattered image imaging method of a further embodiment of the invention when the back-scattered imaging system is disturbed by scattered radiation formed by transmitted radiation from the transmission imaging system.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless it is specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description. Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate. In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.
In the description of the present invention, it should be understood that the terms "first," "second," and the like are used for defining the components, and are merely for convenience in distinguishing the corresponding components, and the terms are not meant to have any special meaning unless otherwise indicated, so that the scope of the present invention is not to be construed as being limited.
In the description of the present invention, it should be understood that the directions or positions indicated by the terms "front, rear, upper, lower, left, right", "transverse, vertical, horizontal", and "top, bottom", etc. are merely for convenience in describing the present invention and simplifying the description, and the terms do not indicate or imply that the devices or elements to be referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus should not be construed as limiting the scope of the present invention; the orientation word "inner and outer" refers to inner and outer relative to the contour of the respective component itself.
The embodiment of the invention provides a back scattering imaging system which mainly comprises a back scattering line source, a back scattering detector, a control device and an imaging device.
The back-scatter source is arranged to perform a scan with a first scanning state in which no scanning beam is emitted and a second scanning state in which a scanning beam is emitted. The backscatter detector detects a first backscatter signal when a backscatter source of a backscatter imaging system is in a first scanning state and detects a second backscatter signal when the backscatter source is in a second scanning state. The control device is in signal connection with the backscatter detector, and is arranged to modify the second backscatter signal with a modification signal formed from the first backscatter signal to obtain a modified backscatter signal, and to form the graphical information from the modified backscatter signal. The imaging device is in signal connection with the control device and is used for generating a back scattering image in a second scanning state according to the graphic information.
In the back-scattering imaging system of the above embodiment, the first back-scattering signal is a back-scattering signal measured when the back-scattering line source does not emit a scanning beam, the first back-scattering signal may be regarded as an interference signal generated when an ambient interference ray performs an inspection on the back-scattering imaging system, the second back-scattering signal may be regarded as a combined signal of an effective signal and an interference signal formed by mixing a reflected ray of the scanning light emitted from the back-scattering line source after striking the object with the ambient interference ray, and the corrected back-scattering signal formed by correcting the second back-scattering signal according to the corrected signal formed by the first back-scattering signal may be at least partially removed on the basis of the combined signal, so that the obtained back-scattering image is clearer.
Wherein the disturbing radiation may be any disturbing radiation from the environment, for example a disturbing from a transmission imaging system or other back-scattering imaging system of the same scanning inspection system or of a different scanning inspection system. For scanning inspection systems that integrate a transmission imaging system and a backscatter imaging system, interference of the transmission imaging system with the backscatter imaging system may be reduced.
In some embodiments, the back-scatter source is configured to have a ratio of 1% to 51% of the time in the first scanning state to the sum of the times in the first scanning state and the second scanning state. For example, the ratio of the time may be set to 3%, 5%, 8%, 10%, 12%, 15%, 18%, 25%, 35%, 40%, 50%, or the like.
The back-scatter source comprises a radiation source and a flying spot device, wherein the flying spot device can be in various forms, for example, in the embodiment shown in fig. 3 and 4, the radiation source is an X-ray machine, and the flying spot device comprises a flywheel 1 provided with a beam hole and a fan-shaped box 2 provided with a collimation slit.
Fig. 3 is a schematic plan view of a principle of a back-scatter source in a back-scatter imaging system of a scanning inspection system, and fig. 4 is a schematic perspective view of a principle of a back-scatter source in a back-scatter imaging system of a scanning inspection system.
As shown in fig. 3 and 4, the flying spot device includes a flywheel 1 and a fan-shaped case 2. The flywheel 1 is rotatable relative to the segment case 2. The flywheel 1 comprises a wheel disc and a wheel rim which is arranged on the periphery of the wheel disc and covers the radial outer side of the fan-shaped box 2, and a plurality of beam holes for radially emitting light are arranged along the circumferential direction of the wheel rim. The fan-shaped box 2 and the rim are coaxially arranged on the side surface of the rim and are located on the radial inner side of the rim, a light receiving hole for receiving X rays emitted by a beam outlet point G of an X-ray machine is formed in the circle center of the fan-shaped box 2, and an alignment slit of the X rays is formed in the arc-shaped surface of the fan-shaped box 2. Each beam hole can only transmit X-rays when being positioned in the light emergent region covered by the light emergent angle of the fan-shaped box 2, and can not transmit X-rays when being positioned outside the light emergent region of the fan-shaped box 2.
In the embodiment shown in fig. 3 and fig. 4, O is the center of the flywheel 1, and four beam holes, namely, a beam hole a, a beam hole b, a beam hole c and a beam hole d, are formed in the flywheel 1. Every two adjacent beam holes in the four beam holes have an interval angle of 90 degrees along the circumferential direction. The light emitting angle of the fan-shaped box 2 is smaller than the interval angle of the adjacent beam holes, namely, the angle of the transmitted rays of each beam hole is smaller than 90 degrees, for example, when the light emitting angle accounts for 90% of the interval angle of the adjacent beam holes, namely, the light emitting angle is 81 degrees, and 10% of the X rays cannot be transmitted to the inspected object through the flying spot device.
In fig. 3 and fig. 4, two end points OF the collimation slit are a first end point E and a second end point F, respectively, and an included angle between a connecting line OE OF the center O and the first end point E and a connecting line OF the center O and the second end point F is an emergent angle, which is 81 degrees in this embodiment. In this embodiment, the first end point E is located at one edge (upper edge in fig. 3 and 4) of the segment case 2, and the second end point F is located at the other edge (lower edge in fig. 3 and 4) of the segment case 2.
When four beam holes a, b, c, d pass through the fan-shaped case 2 having an exit angle of 81 degrees, spot-shaped X-rays can be emitted from the back-scattering line source. For example, when the flywheel 1 rotates clockwise, the spot-shaped X-rays are emitted from the first end point E to the second end point F during the 81-degree light emitting angle from the first end point E to the second end point F, and the beam hole b has not entered the light emitting area of the fan-shaped case 2 just after the beam hole a is moved out from the second end point F located at the lower edge of the fan-shaped case 2, and is spaced apart from the first end point E located at the upper edge of the fan-shaped case 2 by 9 degrees. Similarly, when the beam hole b just moves out from the second end point F positioned at the lower edge of the fan-shaped box 2, the beam hole c does not enter the light emergent region of the fan-shaped box 2 yet and is 9 degrees away from the first end point E positioned at the upper edge of the fan-shaped box 2; when the beam hole c just moves out from the second end point F positioned at the lower edge of the fan-shaped box 2, the beam hole d does not enter the light emergent region of the fan-shaped box 2 yet and is 9 degrees away from the first end point E positioned at the upper edge of the fan-shaped box 2; when the beam hole d has just been moved out from the second end point F located at the lower edge of the fan-shaped case 2, the beam hole a has not yet entered the light emitting region of the fan-shaped case 2, and is further 9 degrees from the first end point E located at the upper edge of the fan-shaped case 2.
In the embodiment shown in fig. 3 to 4, the flywheel 1 starts the next row of scanning immediately after one beam hole leaves the second end point F of the fan-shaped case 2, and at the beginning of each row of scanning, the beam hole that is about to enter the light emitting region of the fan-shaped case 2 cannot emit rays, so that the back-scattering line source is in the first scanning state that does not emit scanning light beams, and the beam hole emits rays when passing through the light emitting region of the fan-shaped case 2, so that the back-scattering line source is in the second scanning state that emits scanning light beams. It can be seen that in this embodiment, the back-scatter source has a first scanning state when performing each column of scanning.
Since the flywheel 1 rotates at a constant speed during normal scanning, in this embodiment, from the start of each column of scanning, the ratio of the angle through which the corresponding beam hole rotates in the first scanning state to the angle through which the beam hole rotates in the first scanning state and the second scanning state, that is, the ratio of the light exit angle of the fan-shaped case 2 to the interval angle between adjacent beam holes, is identical to the ratio of the sum of the time in the first scanning state and the time in the first scanning state. Therefore, in the present embodiment, the ratio of the time in the first scanning state to the sum of the times in the first scanning state and the second scanning state is 10%.
In the embodiment not shown, the number and arrangement of the beam holes are not limited to the form of fig. 3 and 4. For example, the number of the beam holes may be set to 3, and the 3 beam holes are disposed at intervals of 120 degrees.
The ratio of the light exit angle of the fan-shaped case 2 to the interval angle between the adjacent beam holes is not limited to 10%, and may be appropriately set according to circumstances, for example, in some embodiments, may be set to a certain value between 5% and 20%, for example, may be set to 6%,8%,12%,15%,18%, etc., in other embodiments, may be set to a value below 5%, as long as it is ensured that at least one first back-scattered signal can be acquired, for example, a certain value between 1% and 5%, and in other embodiments, may be set to a certain value above 20%, for example, 20% to 51%.
The control means is, for example, a computer, a general-purpose processor, a Programmable Logic Controller (PLC), a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), or the like, which can be implemented to perform the functions described by the present invention.
In some embodiments, the backscatter imaging system includes a speed sensor. The speed sensor is used for measuring the relative movement speed of the detected object and the back scattering imaging system so as to form a speed signal. The control device is in signal connection with the speed sensor to receive the speed signal and to modify the second backscatter signal with a modification signal formed from the speed signal and the first backscatter signal to form a modified backscatter signal. For example, when the relative movement speed is low, the second backscatter signal may be corrected so that one correction signal is shared by several rows of scanning, and when the relative movement speed is high, the second backscatter signal may be corrected so that each row of scanning uses a separate correction signal.
The back-scatter source of the back-scatter imaging system may be arranged to have a first scanning state when performing each column of scans or may be arranged to have a first scanning state when performing more than two columns of scans consecutively.
The embodiment of the invention also provides a scanning inspection system comprising the back scattering imaging system of the previous embodiment. In the scanning inspection system, the interference of the environment or the internal interference factors of the scanning inspection system on the back scattering imaging system can be reduced.
The scanning inspection system may also include a transmission inspection system. The scanning inspection system can reduce interference of the transmission imaging system on the back scattering imaging system. The transmission radiation source of the transmission imaging system can be a transmission radiation source which continuously outputs beam current, such as an x-ray machine or an isotope source.
The embodiment of the invention also provides a back scattering image imaging method of the back scattering imaging system, which comprises the following steps: a back scatter detector of the back scatter imaging system detects a first back scatter signal in a first scanning state without a scanning beam emitted by a scanning light beam when a back scatter line source of the back scatter imaging system performs scanning; the back scattering detector emits a second back scattering signal in a second scanning state of the scanning light beam when the back scattering line source performs scanning; modifying the second backscatter signal with a modification signal formed from the first backscatter signal to obtain a modified backscatter signal and forming graphical information from the modified backscatter signal; and generating a back scattering image in the second scanning state according to the graphic information.
The back scattering image imaging method based on the embodiment of the invention has the same advantages as the back scattering imaging system of the previous embodiment of the invention, and the influence of interference signals can be at least partially removed on the basis of the integrated signals, so that the obtained back scattering image is more real.
FIG. 5 is a back-scattered image of a back-scattered imaging system of a scanning inspection system not disturbed by scattered radiation formed by transmitted radiation of the transmission imaging system. FIG. 6 is a non-interference-free back-scattered image produced when a back-scattered imaging system of a scanning inspection system is interfered with scattered radiation formed by transmitted radiation of the transmission imaging system. As can be seen from comparing fig. 5 and fig. 6, the portion of the image of the disturbed back-scattered image formed by the interference of the back-scattered image caused by the scattered radiation formed by the transmitted radiation of the transmission imaging system is unclear, and the overall imaging quality is poor.
FIG. 7 is a back-scattered image of a scan inspection system with the back-scattered image being removed by a back-scattered image imaging method of an embodiment of the invention when the back-scattered imaging system is disturbed by scattered radiation formed by transmitted radiation from the transmission imaging system. FIG. 8 is a back-scattered image of a scan inspection system with the back-scattered image being removed by another embodiment of the invention when the back-scattered image system is disturbed by scattered radiation formed by transmitted radiation from the transmission imaging system. FIG. 9 is a back-scattered image of a scan inspection system with the back-scattered image being removed by a back-scattered image imaging method of a further embodiment of the invention when the back-scattered imaging system is disturbed by scattered radiation formed by transmitted radiation from the transmission imaging system. Comparing fig. 7 to 9 with fig. 5 and fig. 6, it can be seen that, after the interference of the scattered radiation formed by the transmitted radiation of the transmission imaging system is removed by using the back-scattered image imaging method according to the embodiments of the present invention, the back-scattered image in the second scanning state is closer to the case of no interference of the transmission imaging system shown in fig. 6, and the overall image of the back-scattered image is clear, and the imaging quality is better.
In fig. 5 to 9, the area marked by the height h is a scattering image formed according to the detected first back scattering signal when the beam hole does not enter the light emitting area of the fan-shaped box 2 yet (in the first scanning state), and the part of the scattering image is a background; the area below the background is the back scattering image when the beam aperture has entered the light exit area of the fan-shaped box 2 (in the second scanning state). The second back scattering signal is modified by the modification signal formed according to the first back scattering signal to form a modified back scattering signal, and a back scattering image in a second scanning state is formed according to the pattern information formed by the modified back scattering signal, so that the background is subtracted from the back scattering image in the second scanning state, and the imaging quality of the back scattering image in the second scanning state can be improved.
As shown in fig. 7 to 9, the specific method of forming the correction signal using the first backscatter signal may be different, and the resulting effect may be different, but the purpose of improving the quality of the backscatter image may be achieved.
In some embodiments, modifying the second backscatter signal with the modification signal to form the modification backscatter signal includes subtracting the product of the modification signal and the modification coefficient from the second backscatter signal to form the modification backscatter signal. For example, the correction coefficient ranges from 0.8 to 1.2. For example, 0.85, 0.90, 0.95, 0.98, 1.0, 1.03, 1.05, 1.08, 1.12, 1.15, 1.17, etc. are possible. Preferably, in the present embodiment, the correction coefficient is 1.
In some embodiments, the second backscatter signal when performing a column scan may be modified with one first backscatter signal in the first scan state when the backscatter source performs the column scan as a modification signal. This correction method is hereinafter referred to as a single point correction method.
Fig. 7 shows a common back-scattered image of the first and second scan states formed by correcting the second back-scattered signal using a single point correction method. The first backscatter signal used as the correction signal may be any one of the first backscatter signals in the first state when the column scanning is performed. For example, if the back scatter detector measures a total of 8 first back scatter signals in the first state when performing a column scan, any one of the 8 first back scatter signals may be taken, for example, the 4 th or 6 th first back scatter signal as a correction signal.
In some embodiments, the second backscatter signal when performing a column scan may be modified with the mean of the two or more first backscatter signals in the first scan state when the backscatter source performs the column scan as the modification signal. The correction method is hereinafter referred to as a single-column multipoint average correction method.
Fig. 8 shows a common back-scattered image in the first state and the second scanning state, which are formed by correcting the second back-scattered signal by using the single-column multi-point average correction method. The first backscatter signals for forming the correction signals may be any two or more first backscatter signals in the first state when the column scanning is performed. For example, if the back scatter detector measures 8 first back scatter signals in total in the first state when performing a column scan, the average of any of the 8 first back scatter signals, for example, the average of the 4 th and 6 th first back scatter signals, or the average of the 3 rd, 5 th and 7 th first back scatter signals, or the average of all 8 first back scatter signals, may be taken as a correction signal, etc.
In some embodiments, the second back-scattered signal when two or more columns of scans are performed may also be corrected with the average value of the two or more first back-scattered signals in the first scanning state when the back-scattered line source continuously performs the two or more columns of scans as the correction signal. The correction method is hereinafter referred to as a multi-column multi-point average correction method.
For example, the second back-scattered signal when the two or more scans are performed may be corrected with the average value of the two or more first back-scattered signals in the first scanning state of the same column scan as the correction signal.
For another example, the second back-scattered signal when the two or more columns of scanning are performed may be corrected with the average value of the two or more first back-scattered signals in the first scanning state of the at least two columns of scanning as the correction signal. In the first scanning state of each column of scanning, two or more first back scattering signals may be selected, and the average value of all the selected first back scattering signals is used as a correction signal to correct the second back scattering signals when the two or more columns of scanning are performed.
Fig. 9 shows a common back-scattered image in the first state and the second scanning state, which are formed by correcting the second back-scattered signal by using the multi-column multi-point average correction method. The first backscatter signals for forming the correction signals may be any two or more first backscatter signals in the first state when the two or more scanning lines are executed. For example, if two or more columns are 3 columns, the back scatter detector can measure 8 first back scatter signals in the first state when each column is performed, and then 24 first back scatter signals in total, an average of any several of the 24 first back scatter signals may be taken, for example, an average of the 4 th and 6 th first back scatter signals when each column is scanned in 3 columns, or an average of the 3 rd, 5 th and 7 th first back scatter signals when each column is scanned in 3 columns, or an average of all 24 first back scatter signals as a correction signal, or the like.
Compared with the single-point correction method, the single-column multi-point average correction method and the multi-column multi-point average correction method are adopted, interference signals removed from the second back-scattered signals are more average, and the obtained back-scattered images in the second scanning state are clearer.
In some embodiments, the second back-scattered signal when two or more columns of scans are performed may also be corrected by using one first back-scattered signal in the first scanning state when the back-scattered line source continuously performs two or more columns of scans as a correction signal.
In some embodiments, the back-scattered image imaging method may further comprise: measuring the relative movement speed of the object to be detected and the back scattering imaging system to form a speed signal; the second backscatter signal is modified with a modification signal formed from the velocity signal and the first backscatter signal to form a modified backscatter signal.
For example, when the velocity signal indicates that the relative movement velocity is greater than the predetermined relative movement velocity, the second backscatter signal when the two or more scans are performed is corrected with the average value of the two or more first backscatter signals in the first scanning state of the same column of scanning as the correction signal (single column multipoint correction method). For another example, when the velocity signal indicates that the relative movement velocity is less than or equal to the predetermined relative movement velocity, the second backscatter signal when the two or more rows of scanning is performed is corrected with the average value of the two or more first backscatter signals in the first scanning state of the at least two rows of scanning as the correction signal (multi-row multipoint correction method).
When the relative moving speed is larger than the preset relative moving speed, background change of the back scattering images in the adjacent columns is larger, and the single-column multipoint correction method is adopted to correct the second back scattering signals, so that the integral quality of the back scattering images is guaranteed; when the relative moving speed is smaller than or equal to the preset relative moving speed, background change of the back scattering images of the adjacent columns is not large, and the time and the workload for calculation can be saved by adopting the multi-column multipoint correction method to correct the second back scattering signals.
The above embodiments are not intended to limit the invention, for example, the flying spot device of a back-scatter source includes a rotating drum provided with a collimation slit. In order to make the back-scattering line source have the first scanning state and the second scanning state when scanning is executed, the corresponding light inlet collimation slit and light outlet collimation slit on the rotary cylinder are matched and arranged so that the rotary cylinder does not emit scanning light beams when rotating to a partial angle. For example, in designing the collimation slit position of the rotating drum, the first backscatter signal may be measured at each rotation period of the rotating drum, set to be such that radiation cannot pass through the flying spot device within a certain proportion of the angle.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same; while the invention has been described in detail with reference to the preferred embodiments, those skilled in the art will appreciate that: modifications may be made to the specific embodiments of the present invention or equivalents may be substituted for part of the technical features thereof; without departing from the spirit of the invention, it is intended to cover the scope of the invention as claimed.
Claims (16)
1. A backscatter imaging system, comprising:
a back-scatter source arranged to have a first scanning state in which no scanning beam is emitted and a second scanning state in which a scanning beam is emitted when scanning is performed;
A backscatter detector that detects a first backscatter signal when a backscatter source of the backscatter imaging system is in the first scanning state and detects a second backscatter signal when the backscatter source is in the second scanning state;
Control means, in signal communication with said backscatter detectors, arranged to modify said second backscatter signal with a modification signal formed from said first backscatter signal to obtain a modified backscatter signal and to form graphical information from said modified backscatter signal; and
And the imaging device is in signal connection with the control device and generates a back scattering image in the second scanning state according to the graphic information.
2. The backscatter imaging system of claim 1, wherein the backscatter source is configured to have a ratio of time in the first scanning state to the sum of time in the first scanning state and the second scanning state of 1% to 51%.
3. The back-scatter imaging system according to claim 1, characterized in that the back-scatter source comprises a radiation source and a flying spot device, wherein the flying spot device comprises a flywheel (1) provided with a beam aperture and a fan-shaped box (2) provided with a collimation slit, or the flying spot device comprises a rotating drum provided with a collimation slit.
4. The backscatter imaging system of claim 1, comprising a speed sensor for measuring a relative movement speed of the subject and the backscatter imaging system to form a speed signal, the control device being in signal communication with the speed sensor and modifying the second backscatter signal to form the modified backscatter signal based on the speed signal and the first backscatter signal.
5. The backscatter imaging system of claim 1, wherein the backscatter source is configured to have the first scan state when each column of scans is performed or the first scan state when more than two columns of scans are performed consecutively.
6. A scanning inspection system comprising the backscatter imaging system of any one of claims 1 to 5.
7. The scanning inspection system of claim 6, further comprising a transmission inspection system.
8. A method of imaging a backscatter image of a backscatter imaging system, comprising:
A back scatter detector of the back scatter imaging system detects a first back scatter signal in a first scanning state without a scanning light beam emitted when a back scatter line source of the back scatter imaging system performs scanning;
The back scatter detector detects a second back scatter signal in a second scanning state of emitting a scanning beam when the back scatter source performs scanning;
modifying the second backscatter signal with a modification signal formed from the first backscatter signal to obtain a modified backscatter signal, and forming graphical information from the modified backscatter signal;
and generating a back scattering image in the second scanning state according to the graphic information.
9. The method of claim 8, wherein modifying the second backscatter signal with a modification signal formed from the first backscatter signal to obtain a modified backscatter signal comprises subtracting a product of the modification signal and a modification factor from the second backscatter signal to form the modified backscatter signal.
10. The back-scattered image imaging method of claim 9, wherein the correction factor is in the range of 0.8 to 1.2.
11. The method according to claim 8, wherein the second back-scattered signal when performing a column scan is corrected with one of the first back-scattered signals in the first scanning state when the back-scattered line source performs the column scan or with a mean value of two or more of the first back-scattered signals in the first scanning state when the back-scattered line source performs the column scan as the correction signal.
12. The method according to claim 8, wherein the second back-scattered signal when two or more columns of scans are performed is corrected with one of the first back-scattered signals in the first scanning state when the back-scattered line source continuously performs two or more columns of scans or with a mean value of two or more of the first back-scattered signals in the first scanning state when the back-scattered line source continuously performs two or more columns of scans as the correction signal.
13. The method of imaging a back-scattered image of claim 12,
Correcting the second back-scattered signal when the two or more columns of scanning are performed with the average value of the two or more first back-scattered signals in the first scanning state of the same column of scanning as the correction signal; or (b)
And correcting the second back-scattered signal when the two or more columns of scanning are performed with an average value of the two or more first back-scattered signals in the first scanning state of at least two columns of scanning as the correction signal.
14. The method according to claim 13, wherein two or more of the first back-scattered signals are selected in the first scanning state of each column of scanning, and the second back-scattered signals when the two or more columns of scanning are performed are corrected with a mean value of all the selected first back-scattered signals as the correction signal.
15. The back-scattered image imaging method of any of claims 8 to 14, comprising:
Measuring the relative movement speed of the object to be detected and the back scattering imaging system to form a speed signal;
and correcting the second back scattering signal according to the speed signal and the correction signal formed by the first back scattering signal to form the correction back scattering signal.
16. The method according to claim 15, wherein when the velocity signal indicates that the relative movement velocity is greater than a predetermined relative movement velocity, the second backscatter signals when two or more of the first backscatter signals in the first scanning state of the same column of scanning are corrected and executed with an average value of the two or more of the first backscatter signals as a correction signal; the speed signal indicates that when the relative movement speed is less than or equal to the predetermined relative movement speed, the second backscatter signals when two or more of the scans are performed are corrected with an average value of the two or more of the first backscatter signals in the first scanning state of at least two of the scans as a correction signal.
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| CN201811291946.2A CN109142404B (en) | 2018-11-01 | 2018-11-01 | Back-scattering imaging system, scanning inspection system and back-scattering image imaging method |
| PCT/CN2019/109936 WO2020088198A1 (en) | 2018-11-01 | 2019-10-08 | Backscatter imaging system, scanning inspection system, and backscatter imaging method |
| PL437748A PL245844B1 (en) | 2018-11-01 | 2019-10-08 | Backscatter imaging system, scanning inspection system, and backscatter imaging method |
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| PL245844B1 (en) | 2024-10-21 |
| CN109142404A (en) | 2019-01-04 |
| WO2020088198A1 (en) | 2020-05-07 |
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