Article detection methods, devices, security inspection equipment, media and program products

Abstract

The present disclosure provides a method for detecting an object, which is applied to a security inspection device, wherein the security inspection device includes a light source, a detector, and a security inspection channel. The method includes: determining a focus offset; changing the focus position of the light source according to the focus offset, so that the light source emits a first X-ray to the scanned object according to the changed focus position, wherein the focus offset is determined according to the position of the scanned object; using the detector to receive the first X-ray emitted by the light source to obtain detection data of the first X-ray; and detecting the scanned object according to the detection data of the first X-ray. The present disclosure also provides an object detection device, a security inspection device, a medium, and a program product.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to the field of security inspection, and in particular to an object detection method, device, security inspection equipment, medium, and program product. Background Art

[0002] X-ray imaging (X-ray CT) technology is an important method of non-destructive testing. It has been widely used in many fields, such as medicine and security inspection. X-ray CT technology collects projection images of the scanned object at different angles, and then performs mathematical reconstruction based on the reconstruction algorithm to obtain three-dimensional tomographic data of the scanned object. Compared with single-view DR (Digital Radiography) detection, X-ray imaging can greatly improve detection accuracy, so it is widely used in scenarios with high detection accuracy requirements.

[0003] In existing CT technology solutions, a common structure for obtaining projection images at different angles is to rotate the light source and detector. The detector can be a multi-row or surface array detector. The most basic module of the detector is a pixel, and each detector pixel has a size. Due to the limitations of the sampling law, the size of the detector pixel will restrict the spatial resolution of the reconstructed object. Having a higher spatial resolution can improve the accuracy of detection, so improving the spatial resolution is crucial for CT technology.

[0004] At present, X-ray source flying focus technology has been successfully applied to high-end medical diagnostic CT machines. X-ray source flying focus technology can obtain additional information during the scanning process by changing the position of the electron beam bombarding the tungsten target during the X-ray source generation process.

[0005] The above-mentioned X-ray source flying focus scanning scheme is used to scan the human body, and the volume and shape of the human body are basically the same, so the degree of focus position offset in this scheme is relatively unchanged during the rotation of the slip ring. In the field of article security inspection, due to the great diversity of scanned objects, the scanning channel is often very large (much larger than the cross-sectional area of ​​the object), so the center position of most scanned objects is not at the rotation center of the slip ring, but somewhere between the middle of the channel belt and the rotation center. Therefore, if the flying focus scheme in the medical field is directly applied to the field of article security inspection, the main part of the object will not get the best encrypted sampling, which weakens the effectiveness of this method to a certain extent. Summary of the invention

[0006] According to an embodiment of the present disclosure, a method, apparatus, security inspection equipment, medium and program product for detecting an object are proposed.

[0007] In one aspect of the present disclosure, a method for detecting an object is proposed, which is applied to a security inspection device, wherein the security inspection device includes a light source, a detector, and a security inspection channel; the method includes: determining a focus offset; changing a focus position of the light source according to the focus offset, so that the light source emits a first X-ray to the scanned object according to the changed focus position, wherein the focus offset is determined according to the position of the scanned object; receiving the first X-ray emitted by the light source by the detector to obtain detection data of the first X-ray; and detecting the scanned object according to the detection data of the first X-ray.

[0008] According to an embodiment of the present disclosure, determining the focus offset includes: determining the coordinates of at least one reference point; and determining the focus offset based on the coordinates of the at least one reference point and the coordinates of the light source and the detector through which the rays of the light source passing through the reference point pass.

[0009] According to another embodiment of the present disclosure, determining the coordinates of at least one reference point includes: using the detector to receive a second X-ray emitted by the light source at a horizontal position on a horizontal plane to obtain detection data of the second X-ray; generating a projection map based on the detection data of the second X-ray; and determining the coordinates of the at least one reference point based on the generated projection map.

[0010] According to another embodiment of the present disclosure, determining the coordinates of the at least one reference point based on the generated projection image includes: determining the first boundary point and the second boundary point of the scanned object based on the projection image; and determining the coordinates of the at least one reference point based on the first boundary point, the second boundary point and the horizontal position coordinates.

[0011] According to another embodiment of the present disclosure, the determining of the coordinates of the at least one reference point based on the first boundary point, the second boundary point and the horizontal position coordinates includes: determining the coordinates of the reference point based on an angle formed by a line from the first boundary point to the light source and the horizontal plane, an angle formed by a line from the second boundary point to the light source and the horizontal plane, and the coordinates of the horizontal position.

[0012] According to another embodiment of the present disclosure, determining the coordinates of the at least one reference point includes: acquiring multiple historical scan images; and determining the center of mass coordinates of the scanned object in each of the multiple historical scan images; and determining the coordinates of the at least one reference point based on the center of mass coordinates of the scanned object in each of the historical scan images.

[0013] According to another embodiment of the present disclosure, determining the coordinates of at least one reference point includes: determining a target area; and determining at least one reference point from the target area, and acquiring the coordinates of the at least one reference point.

[0014] According to another embodiment of the present disclosure, determining the target area includes: acquiring a plurality of historical scan images; and determining an area with the most imaging details in the plurality of historical scan images as the target area.

[0015] According to another embodiment of the present disclosure, determining the target area includes: acquiring a plurality of historical scan images; and determining an area in which the scanned object appears most frequently in the plurality of historical scan images as the target area.

[0016] According to another embodiment of the present disclosure, the security inspection equipment also includes at least one optical sensor; the determining of the coordinates of at least one reference point includes: using the at least one optical sensor to collect at least one optical image of the scanned object; and determining the coordinates of the at least one reference point based on the at least one optical image.

[0017] According to another embodiment of the present disclosure, changing the focal position of the light source according to the focus offset includes: determining weights of multiple focus offsets when there are multiple focus offsets; determining an average offset according to the weights of the multiple focus offsets; and changing the focal position of the light source according to the average offset.

[0018] According to another embodiment of the present disclosure, determining the weights of the multiple focus offsets includes: determining the weights of the focus offsets corresponding to the reference points according to the probability of the scanned object appearing at the reference points.

[0019] According to another embodiment of the present disclosure, determining the weights of the multiple focus offsets includes: determining the weight of the focus offset corresponding to each reference point according to the importance of the scanned object at the reference point.

[0020] According to another embodiment of the present disclosure, determining the weights of the multiple original offsets includes: determining the weight of the focus offset corresponding to each reference point according to the article composition of the scanned article at the reference point.

[0021] According to another embodiment of the present disclosure, the reference point coordinates are the determined center coordinates of the scanned object, and the center coordinates are adjusted in real time according to different scanned objects.

[0022] In another aspect of the present disclosure, a device for detecting an object is provided, which is applied to a security inspection device, wherein the security inspection device includes a light source, a detector and a security inspection channel; the device includes: a determination module, which is used to determine a focus offset; a change module, which is used to change the focus position of the light source according to the focus offset, so that the light source emits a first X-ray to the scanned object according to the changed focus position; a receiving module, which is used to receive the first X-ray emitted by the light source using the detector to obtain detection data of the first X-ray; and a detection module, which is used to detect the scanned object according to the detection data of the first X-ray.

[0023] In another aspect of the present disclosure, a security inspection device is proposed, including a light source, a detector, a security inspection channel, a memory and at least one processor; wherein the security inspection channel is used to carry the linear motion of the scanned object, the light source includes at least one ray source point, and the at least one ray source point is arranged on a plane perpendicular to the motion direction of the scanned object, and the offset of the focus of the at least one ray source point is determined according to the position of the scanned object, the detector includes at least one detection unit, and the at least one detection unit is arranged on a plane parallel to the plane of the light source, and is used to receive X-rays that penetrate the scanned object, the memory is used to store instructions, and the at least one processor is used to execute the instructions stored in the memory to implement the method described in any of the above embodiments.

[0024] According to an embodiment of the present disclosure, the light source further includes at least one control mechanism, and the at least one control mechanism is used to control the electron beam flow direction of the at least one ray source point to change the focal position of the at least one ray source point.

[0025] A computer-readable storage medium is applied to a security inspection device, wherein the security inspection device includes a light source, a detector and a security inspection channel. The computer-readable storage medium stores computer instructions, and when the computer instructions are executed by a processor, any of the above embodiments is implemented.

[0026] In another aspect of the present disclosure, a computer program product is provided, comprising executable instructions, which implement the method described in any of the above embodiments when executed by a processor.

[0027] According to the embodiments of the present disclosure, the focus offset is determined according to the position of the scanned object, so that the focus offset distance of the light source can be adaptively adjusted according to different scanned objects, so that the focus of the light source adaptively matches the size of the scanned object. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to better understand the embodiments of the present disclosure, the embodiments of the present disclosure will be described in detail according to the following drawings:

[0029] Figure 1A The application scenarios of the object detection method and device according to the embodiments of the present disclosure are schematically shown;

[0030] Figure 1B A schematic diagram exemplarily illustrates the working principle of the flying focus optical machine according to an embodiment of the present disclosure;

[0031] Figure 2 A flowchart of a method for detecting an object according to an embodiment of the present disclosure is schematically shown;

[0032] Figure 3 A flowchart for determining a focus offset according to an embodiment of the present disclosure is schematically shown;

[0033] Figure 4 A schematic diagram schematically shows a method for determining the center coordinates of a scanned object according to an embodiment of the present disclosure;

[0034] Figure 5 A schematic diagram of determining an amplification ratio according to an embodiment of the present disclosure is schematically shown;

[0035] Figure 6 Schematically shows a flying focus geometry diagram of an object along a fan angle direction according to an embodiment of the present disclosure;

[0036] Figure 7 Schematically shows a geometric diagram of a flying focus of an object along a forward direction according to an embodiment of the present disclosure;

[0037] Figure 8 A block diagram schematically shows an apparatus for detecting an object according to an embodiment of the present disclosure; and

[0038] Fig. 9 An example structural diagram of a security inspection device suitable for implementing a method according to an embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0039] The specific embodiments of the present disclosure will be described in detail below. It should be noted that the embodiments described herein are only for illustration and are not intended to limit the present disclosure. In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it is apparent to those of ordinary skill in the art that these specific details need not be adopted to implement the present disclosure. In other examples, in order to avoid confusing the present disclosure, known structures, materials or methods are not specifically described.

[0040] Throughout the specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present disclosure. Therefore, the phrases "in one embodiment," "in an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily all refer to the same embodiment or example. In addition, particular features, structures, or characteristics may be combined in one or more embodiments or examples in any appropriate combination and / or subcombination. In addition, those of ordinary skill in the art will appreciate that the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0041] The embodiment of the present disclosure proposes a method for detecting an object, which can be applied to a security inspection device, which can include, for example, a light source, a detector, and a security inspection channel. The method includes: determining a focus offset; changing the focus position of the light source according to the focus offset, so that the light source emits a first X-ray to the scanned object according to the changed focus position, wherein the focus offset is determined according to the position of the scanned object; using the detector to receive the first X-ray emitted by the light source to obtain detection data of the first X-ray; and detecting the scanned object according to the detection data of the first X-ray.

[0042] Figure 1A The following schematically illustrates the application scenarios of the object detection method and device according to the embodiments of the present disclosure. It should be noted that: Figure 1A The examples shown are merely scenarios in which the embodiments of the present disclosure can be applied, to help those skilled in the art understand the technical content of the present disclosure, but do not mean that the embodiments of the present disclosure cannot be used in other devices, systems, environments or scenarios.

[0043] like Figure 1A As shown, the application scenario 100 includes a security inspection device and a scanned object 20. The security inspection device includes a slip ring 11, a light source 12, a detector 13 and a security inspection channel 14. The dotted circle represents the slip ring 11. The dotted frame in the middle of the slip ring 11 represents the cross section of the security inspection channel 14. The security inspection channel 14 is located inside the slip ring 11, and the scanned object 20 is placed at the bottom of the security inspection channel 14. The security inspection channel 14 can be used to carry the scanned object for linear motion, and the motion direction of the scanned object is perpendicular to the plane where the slip ring 11 is located. The light source 12 and the detector 13 are correspondingly arranged and fixed on the slip ring 11, and can make a circular motion around the security inspection channel 14 along the slip ring 11. The light source 12 can be used to emit X-rays in the direction of the scanned object. The light source 12 includes a control mechanism for controlling the direction of the electron beam of the light source to change the focal position of the light source. The detector 13 can be used to receive X-rays that penetrate the scanned object. In this embodiment, the light source 12 can use a flying focus optical machine.

[0044] Figure 1B A schematic diagram exemplarily shows the working principle of the flying focus optical machine of the embodiment of the present disclosure. Figure 1B The working principle of the flying focus optical machine is further explained.

[0045] The common X-ray source is an electron beam emitted from the cathode, which is accelerated by the electric field and deflected by the magnetic field and hits the rotating anode (or fixed anode target) to generate X-rays. Figure 1B As shown, the flying focus optical machine quickly switches the deflection magnetic field to make the electron beam emitted by the cathode hit different positions of the rotating anode, thereby generating multiple focal points. For example, in this embodiment, the flying focus optical machine is provided with 4 focal points, for example Figure 1B Points A, B, C and D in the image are switched in the order of A->B->C->D as shown by the arrows. It should be noted that the above-mentioned focus setting method is only an example, and the present disclosure does not specifically limit the focus setting method. In practical applications, different focuses can be set according to different needs. For example, to improve the resolution of the object's motion direction, only two focuses A and C can be set. To improve the resolution of the reconstructed plane, only two focuses A and B can be set.

[0046] Continue to return Figure 1A Since the center of the scanned object 20 does not coincide with the center of the security inspection channel 14, the optimal offset distance (dx, dy) of the light source focus will vary with the height of the object and the position of the light source.

[0047] Based on this, according to the present disclosure, a method for detecting an object is provided, which can adjust the focus of the light source according to the height of the object and the position of the light source during the detection process, so as to adaptively match the size of the scanned object.

[0048] It should be noted that the above-mentioned security inspection equipment is only an example. In addition to the above-mentioned slip ring CT system, the security inspection equipment can also adopt a static CT system with fixed positions of the light source and the detector, such as a non-slip ring CT system using a distributed X-ray source. In this non-slip ring CT system, the light source includes a plurality of independent X-ray source points and one or more control mechanisms, wherein the control mechanism is used to control the direction of the electron beam flow of each X-ray source point to change the focal position of the X-ray source point. Correspondingly, the detector includes a plurality of detection units. In the process of using a non-slip ring CT system to detect the scanned object, similar to the method of setting the position offset for the slip ring CT system in the embodiment of the present disclosure, the position offset of the focal point can be configured for each X-ray source point in the non-slip ring CT system, so that the non-slip ring CT system can achieve adaptive matching of the size of the scanned object.

[0049] The method is exemplarily described below by means of a figure. It should be noted that the sequence number of each operation in the following method is only used as a representation of the operation for the purpose of description, and should not be regarded as representing the execution order of the various operations. Unless explicitly stated, the method does not need to be executed completely in the order shown.

[0050] Figure 2 The flowchart of the object detection method according to the embodiment of the present disclosure is schematically shown. The object detection method can be applied to the security inspection device shown in FIG1 , which includes a light source, a detector, a slip ring and a security inspection channel. Figure 2 As shown, the object detection method may include the following operations S210 to S240.

[0051] In operation S210, a focus offset amount is determined.

[0052] In operation S220, a focal position of the light source is changed according to the focal shift amount, so that the light source emits a first X-ray toward the scanned object according to the changed focal position.

[0053] According to an embodiment of the present disclosure, the focus offset may include, for example, dx and dy, and the focus offset along the first direction may be set to dx, and the focus offset along the second direction may be set to dy to change the focus position of the light source. After the setting is completed, a second X-ray is emitted to the scanned object.

[0054] According to an embodiment of the present disclosure, the focus offset can be determined according to the position of the scanned object. For different scanned objects, the focus offset is also different.

[0055] According to an embodiment of the present disclosure, the focus offset may be determined in real time or in non-real time. For example, in this embodiment, the focus offset is determined in real time, and the focus position of the light source may be adjusted in real time based on the real-time determination of the focus offset, thereby adaptively detecting different scanned objects.

[0056] In operation S230, a detector is used to receive a first X-ray emitted by a light source to obtain detection data of the first X-ray.

[0057] According to an embodiment of the present disclosure, the detection data may include, for example, single-energy, dual-energy or energy spectrum data of X-rays.

[0058] In operation S240, the scanned object is detected according to the detection data of the first X-ray.

[0059] According to the embodiments of the present disclosure, the focal position of the light source is changed according to the focal offset, and X-rays are emitted to the scanned object according to the changed focal position. The scanned object is detected based on the detection data of the X-rays. Compared with the ordinary security CT scanning method, the spatial resolution of the detector can be improved without changing the detector equipment.

[0060] Figure 3 The flowchart of determining the focus offset according to an embodiment of the present disclosure is schematically shown. Figure 3 As shown, the focus offset may be determined according to the following operations S310 to S320.

[0061] In operation S310, the coordinates of at least one reference point are acquired.

[0062] According to an embodiment of the present disclosure, at least one reference point may be used to represent the position of the scanned object, and the focus offset may be determined based on the at least one reference point. Exemplarily, in this embodiment, the center coordinates of the scanned object may be used as the reference point.

[0063] According to an embodiment of the present disclosure, for a slip ring type CT system, the light source can be moved to a horizontal position on a horizontal plane by rotating the slip ring, and a detector is used to receive a second X-ray emitted by the light source at the horizontal position to obtain detection data of the second X-ray.

[0064] According to another embodiment of the present disclosure, for a non-slip ring CT system, a detector may be used to receive a second X-ray emitted by an X-ray source point disposed in a horizontal position to obtain detection data of the second X-ray.

[0065] After the detection data of the second X-ray is obtained, a projection map can be generated according to the detection data of the second X-ray, and the center coordinates of the scanned object can be determined according to the projection map as the coordinates of the reference point.

[0066] Exemplarily, in this embodiment, the height of the scanned object can be estimated based on the projection image, assuming that the scanned object is located at the center of the channel, so as to obtain the center coordinates.

[0067] Figure 4 The schematic diagram of determining the center coordinates of the scanned object according to an embodiment of the present disclosure is schematically shown. Figure 4 As shown, in this embodiment, a rectangular coordinate system is established with the center O of the slip ring as the origin, the horizontal direction as the x-axis, and the vertical direction as the y-axis. The light source S can be moved to the rightmost position of the horizontal plane, and the coordinates are expressed as (R, 0), where R is the radius of the slip ring, and then the height of the scanned object is estimated. The estimation method may include, for example, when the light source is at (R, 0), the detector measures the projection image of the scanned object to obtain the left and right boundary positions of the projection image, such as Figure 4 The boundary points J and K in the image are obtained. Then, the left and right boundaries can be converted geometrically to obtain angles θ1 and θ3, where θ1 is the angle between SJ and the y-axis, and θ3 is the angle between SK and the y-axis. Then, the projection angle θ2 of the center of the scanned object is estimated according to the following formula:

[0068]

[0069] After θ2 is calculated, the height of the scanned object can be estimated according to the following tangent formula, and then the center coordinates (0, h) can be obtained:

[0070] h=Rtanθ2

[0071] In the above formula, h is the y-axis coordinate of the center of the scanned object in the established rectangular coordinate system, that is, the height of the scanned object, and θ2 is the angle estimated according to the boundary of the scanned object.

[0072] According to another embodiment of the present disclosure, statistical analysis may be performed on the historical scanned images, so as to determine one or more points with a higher probability of the centroid appearing as reference points based on the statistical data.

[0073] For example, multiple historical scan images can be acquired to determine the centroid coordinates of the scanned object in each historical scan image, and then based on the centroid coordinates of the scanned object in each historical scan image, one or more centroid coordinates with the highest frequency can be determined from these centroid coordinates as the coordinates of the reference point.

[0074] Alternatively, the area with the most imaging details can be determined based on multiple historical scan images, at least one reference point (such as the center point of the area) can be determined from the area with the most imaging details, and the coordinates of at least one reference point of the at least one reference point can be obtained.

[0075] Alternatively, the area where the scanned object appears most frequently in multiple historical scan images can be determined, at least one reference point (such as the center point of the area) can be determined from the area where the scanned object appears most frequently, and the coordinates of at least one reference point of the at least one reference point can be obtained.

[0076] In operation S320, a focus offset is determined based on coordinates of at least one reference point and coordinates of a light source and a detector through which a ray of the light source passing through the reference point passes.

[0077] According to an embodiment of the present disclosure, the object magnification ratio can be determined based on the coordinates of at least one reference point and the coordinates of the light source and the detector through which the ray of the light source passing through the reference point passes, and then the focus offset can be determined based on the object magnification ratio. Figure 5 The schematic diagram of determining the amplification ratio according to the embodiment of the present disclosure is schematically shown. Figure 5As shown, taking the center of the object as the reference point, in the coordinate system established above, the coordinates of the light source S are The coordinates of the reference point M are the center coordinates of the scanned object (0, h). The intersection of the line SM connecting S and M and the detector is point D. Then the coordinates of the intersection point D (Dx, Dy) satisfy the following two equations:

[0078]

[0079] The first equation is the equation of a circle, and the second equation is the equation of a line. For ease of representation, the following variable substitutions are made:

[0080]

[0081] Solving the above equation, we can get:

[0082]

[0083] The magnification ratio L is thus:

[0084]

[0085] That is, the formula can be used to calculate that when the height of the object to be scanned is h, the rotation radius is R, and the light source rotates to an angle The magnification ratio L when .

[0086] Figure 6 The flying focus geometry diagram of an object along the fan angle direction according to an embodiment of the present disclosure is schematically shown. Figure 7 The geometric diagram of the flying focus of an object along the forward direction according to an embodiment of the present disclosure is schematically shown. Figures 6-7 As shown, the size of the pixel in the detector fan angle direction is assumed to be ux, the pixel size in the object forward direction is assumed to be uz, and the inclination angle of the rotating anode is assumed to be γ, then the distance of the focus AC in the forward direction is dysinγ.

[0087] According to the embodiment of the present disclosure, after the X-ray irradiates the scanned object, the offset distance of its center on the detector is 0.45-0.55 pixel width, and the best is 0.5 pixel width. Based on this, in this embodiment, the offset distance of the scanned object can be set to half a pixel (ux / 2, uz / 2). The above relationship can be expressed by the following formula:

[0088]

[0089] When the object to be scanned is located at the center of the channel (the horizontal coordinate is 0), the magnification ratio L is substituted into the above formula to obtain:

[0090]

[0091] The focus offset includes dx and dx, where dx is the focus along the first direction (e.g. Figure 1B AB direction or CD direction), dy is the focus along the second direction (for example Figure 1B For multi-row detectors, ux is the distance between the pixel centers of adjacent rows of detectors in the fan angle direction, uz is the pixel size of the detector along the forward direction of the object to be scanned, for multi-row detectors, uz is the distance between the pixel centers of adjacent rows of detectors in the forward direction, and γ is the inclination angle of the rotating anode in the light source.

[0092] According to other embodiments of the present disclosure, the center coordinates of the scanned object may be obtained by other methods, such as visible light photography, multi-view positioning, etc. Exemplarily, in this embodiment, at least one optical sensor may be provided in the security inspection device, and at least one optical image of the scanned object may be collected by using the optical sensor, and then the center coordinates of the scanned object may be determined based on the at least one optical image.

[0093] Return to reference Figure 5 , if the coordinates of the reference point estimated by other methods are M(l, h), and the intersection of the line SM connecting S and M, S and M and the detector is point D, then the intersection point D(Dx, Dy) satisfies the following two equations:

[0094]

[0095] The first equation is the equation of the circle, and the second equation is the equation of the line. Replace the variables as follows:

[0096]

[0097] Solving this equation, we can get:

[0098]

[0099] The magnification ratio L' is obtained as follows:

[0100]

[0101] Among them, L' is the object magnification ratio, l is the horizontal coordinate in the reference point coordinate, h is the vertical coordinate in the reference point coordinate, R is the radius of the slip ring, It is the angle between the line connecting the light source and the center of the slip ring and the line connecting the light source and the reference point.

[0102] Substitute the amplification ratio L' at this time into the following formula:

[0103]

[0104] After solving, we get:

[0105]

[0106] Among them, the focus offset includes dx and dx, dx is the offset of the focus along the first direction, dy is the offset of the focus along the second direction, ux is the pixel size of the detector along the fan angle direction, for multi-row detectors, it is the distance between the pixel centers of adjacent rows of detectors in the fan angle direction, uz is the pixel size of the detector along the forward direction of the object to be scanned, for multi-row detectors, it is the distance between the pixel centers of adjacent rows of detectors in the forward direction, and γ is the inclination angle of the rotating anode in the light source.

[0107] According to the embodiments of the present disclosure, the focus offset is determined according to the position of the scanned object, so that the focus offset distance of the light source can be adaptively adjusted according to different scanned objects, so that the focus of the light source adaptively matches the size of the scanned object.

[0108] According to another embodiment of the present disclosure, there may be multiple reference points. Accordingly, the focus offset may be determined according to each reference point to obtain multiple focus offsets. Then, the weights of the multiple focus offsets may be determined. According to the weights of the multiple focus offsets, the weighted average of the focus offsets may be calculated to obtain the average offset. According to the average offset, the focal position of the light source may be changed. Exemplarily, in this embodiment, the weight of the focus offset corresponding to the reference point may be determined according to the probability of the scanned object appearing at each reference point. Alternatively, the weight of the focus offset corresponding to the reference point may be determined according to the importance of the scanned object at each reference point. Alternatively, the weight of the focus offset corresponding to the reference point may be determined according to the object composition of the scanned object at each reference point.

[0109] It should be noted that the above method for determining the focus offset weight is only an example. In practical applications, other methods may also be used to determine the focus offset weight, and the present disclosure does not make any specific limitation on this.

[0110] It should be noted that the object detection method of the embodiment of the present disclosure is not only applicable to the situation of four-focal point offset, but also to the situation of using two foci for offset, such as the situation of selecting two foci out of the four foci for offset when the spatial resolution within the plane needs to be increased or the inter-layer spatial resolution in the forward direction needs to be increased. It can also be applicable to the situation of using a three-focal point solution, such as selecting three points A, B, and C, or two points A, B and a target point E in the middle of CD.

[0111] Figure 8The block diagram of the device for detecting an object according to an embodiment of the present disclosure is schematically shown. The device for detecting an object can be applied to security inspection equipment, which can include, for example, a light source, a detector, and a security inspection channel.

[0112] like Figure 8 As shown, the object detection device 800 may include: a determination module 810 , a change module 820 , a receiving module 830 and a detection module 840 .

[0113] The determination module 810 may be used to determine a focus offset.

[0114] The changing module 820 may be used to change the focal position of the light source according to the focal offset, so that the light source emits a first X-ray to the scanned object according to the changed focal position.

[0115] The receiving module 830 may be configured to use a detector to receive the first X-ray emitted by the light source to obtain detection data of the first X-ray.

[0116] The detection module 840 may be used to detect the scanned object according to the detection data of the first X-ray.

[0117] According to the embodiments of the present disclosure, the focus offset is determined according to the position of the scanned object, so that the focus offset distance of the light source can be adaptively adjusted according to different scanned objects, so that the focus of the light source adaptively matches the size of the scanned object.

[0118] It should be noted that the implementation methods, technical problems solved, functions realized, and technical effects achieved of each module / unit / sub-unit in the device part embodiment are the same or similar to the implementation methods, technical problems solved, functions realized, and technical effects achieved of each corresponding step in the method part embodiment, and will not be repeated here.

[0119] Fig. 9 An example structural diagram of a security inspection device suitable for implementing the method described above according to an embodiment of the present disclosure is schematically shown. Fig. 9 The security inspection equipment shown is only an example and should not bring any limitation to the structure, function and scope of use of the embodiments of the present disclosure.

[0120] like Fig. 9 As shown, the security inspection device 900 includes a processor 910 and a computer-readable storage medium 920, a light source 930, a detector 940, and a security inspection channel 950. The security inspection device 900 can execute the method according to the embodiment of the present disclosure.

[0121] According to an embodiment of the present disclosure, the security inspection channel 950 can be used to carry the linear motion of the scanned object. The light source 930 can include at least one ray source point, at least one ray source point is set on a plane perpendicular to the motion direction of the scanned object, and the offset of the focus of at least one ray source point is determined according to the position of the scanned object. The detector includes at least one detection unit, at least one detection unit is set on a plane parallel to the plane of the light source, and is used to receive X-rays that penetrate the scanned object.

[0122] According to an embodiment of the present disclosure, the light source further comprises at least one control mechanism, and the at least one control mechanism is used to control the electron beam flow direction of at least one ray source point to change the focal position of at least one ray source point.

[0123] Specifically, the processor 910 may include, for example, a general-purpose microprocessor, an instruction set processor and / or a related chipset and / or a special-purpose microprocessor (e.g., an application-specific integrated circuit (ASIC)), etc. The processor 910 may also include an onboard memory for cache purposes. The processor 910 may be a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present disclosure.

[0124] The computer-readable storage medium 920 may be, for example, a non-volatile computer-readable storage medium, specific examples of which include but are not limited to: a magnetic storage device, such as a magnetic tape or a hard disk (HDD); an optical storage device, such as a compact disk (CD-ROM); a memory, such as a random access memory (RAM) or flash memory; and the like.

[0125] The computer-readable storage medium 920 may include a computer program 921 , which may include code / computer-executable instructions that, when executed by the processor 910 , cause the processor 910 to perform a method according to an embodiment of the present disclosure or any variation thereof.

[0126] The computer program 921 may be configured to have, for example, a computer program code including a computer program module. For example, in an example embodiment, the code in the computer program 921 may include one or more program modules, for example, including 921A, module 921B, ... It should be noted that the division method and number of modules are not fixed, and those skilled in the art may use appropriate program modules or program module combinations according to actual conditions, and when these program module combinations are executed by the processor 910, the processor 910 may execute the method according to the embodiment of the present disclosure or any variation thereof.

[0127] According to an embodiment of the present invention, at least one of the determining module transmitting module 810, the changing module 820, the receiving module 830, and the detecting module 840 may be implemented as a reference module. Fig. 9The computer program modules described above, when executed by the processor 910, can implement the above-described methods.

[0128] The present disclosure also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiments; or may exist independently without being assembled into the device / apparatus / system. The above computer-readable storage medium carries one or more programs, and when the above one or more programs are executed, the method according to the embodiment of the present disclosure is implemented.

[0129] According to an embodiment of the present disclosure, a computer-readable storage medium may be a non-volatile computer-readable storage medium, for example, may include but is not limited to: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present disclosure, a computer-readable storage medium may be any tangible medium containing or storing a program that may be used by or in conjunction with an instruction execution system, apparatus, or device.

[0130] The flow charts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each box in the flow chart or block diagram can represent a module, a program segment, or a part of a code, and the above-mentioned module, program segment, or a part of a code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flow chart, and the combination of the boxes in the block diagram or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0131] Although the present disclosure has been shown and described with reference to specific exemplary embodiments of the present disclosure, it should be understood by those skilled in the art that various changes in form and details may be made to the present disclosure without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents. Therefore, the scope of the present disclosure should not be limited to the above-mentioned embodiments, but should be determined not only by the appended claims, but also by the equivalents of the appended claims.

Claims

1. A method for detecting an object, applied to a security inspection device, wherein the security inspection device comprises a light source, a detector and a security inspection channel; the method comprises: Determine the coordinates of at least one reference point, wherein the coordinates of the reference point are the determined center coordinates of the scanned object; Determine the magnification ratio of the scanned object according to the coordinates of the at least one reference point, the position of the light source, and the coordinates of the detector through which the ray of the light source passing through the reference point passes, and obtain a focus offset; change the focus position of the light source according to the focus offset, so that the light source emits a first X-ray to the scanned object according to the changed focus position, wherein the focus offset is determined according to the position of the scanned object; using the detector to receive a first X-ray emitted by the light source to obtain detection data of the first X-ray; and The scanned object is detected according to the detection data of the first X-ray.

2. The method according to claim 1, wherein: Determining the coordinates of at least one reference point comprises: receiving, by the detector, a second X-ray emitted by the light source at a horizontal position on a horizontal plane, to obtain detection data of the second X-ray; generating a projection image according to the detection data of the second X-ray; and The coordinates of the at least one reference point are determined according to the generated projection image.

3. The method according to claim 2, wherein: Determining the coordinates of the at least one reference point according to the generated projection map comprises: Determining a first boundary point and a second boundary point of the scanned object according to the projection image; and The at least one reference point coordinate is determined based on the first boundary point, the second boundary point and the horizontal position coordinate.

4. The method according to claim 3, wherein: The determining the coordinates of the at least one reference point based on the first boundary point, the second boundary point and the horizontal position coordinates comprises: The coordinates of the reference point are determined according to the angle formed by the line connecting the first boundary point to the light source and the horizontal plane, the angle formed by the line connecting the second boundary point to the light source and the horizontal plane, and the coordinates of the horizontal position.

5. The method according to claim 1, wherein: The determining the coordinates of the at least one reference point comprises: Acquiring a plurality of historical scan images; and Determining the centroid coordinates of the scanned object in each of the plurality of historical scan images; and The coordinates of the at least one reference point are determined according to the coordinates of the center of mass of the scanned object in each historical scan image.

6. The method according to claim 1, wherein: The determining of the coordinates of at least one reference point comprises: Identify target areas; and At least one reference point is determined from the target area, and the coordinates of the at least one reference point are acquired.

7. The method according to claim 6, wherein: Determining the target area includes: Acquiring a plurality of historical scan images; and An area with the most imaging details in the plurality of historical scanned images is determined as the target area.

8. The method according to claim 6, wherein: Determining the target area includes: Acquiring a plurality of historical scan images; and An area in which the scanned object appears most frequently in the plurality of historical scan images is determined as the target area.

9. The method according to claim 1, wherein: The security inspection equipment also includes at least one optical sensor; The determining of the coordinates of at least one reference point comprises: Using the at least one optical sensor, collecting at least one optical image of the scanned object; as well as The coordinates of the at least one reference point are determined based on the at least one optical image.

10. The method according to claim 1, wherein: Changing the focal position of the light source according to the focal offset includes: In the case where there are multiple focus offsets, determining weights of the multiple focus offsets; determining an average focus offset according to the weights of the plurality of focus offsets; and The focal position of the light source is changed according to the average offset.

11. The method according to claim 10, wherein: Determining the weights of the plurality of focus offsets comprises: According to the probability of the scanned object appearing at each reference point, the weight of the focus offset corresponding to the reference point is determined.

12. The method according to claim 10, wherein: Determining the weights of the plurality of focus offsets comprises: According to the importance of the scanned object at each reference point, the weight of the focus offset corresponding to the reference point is determined.

13. The method according to claim 10, wherein: Determining the weights of the plurality of original offsets comprises: The weight of the focus offset corresponding to each reference point is determined according to the article composition of the scanned article at the reference point.

14. An article detection device, applied to a security inspection device, the security inspection device comprising a light source, a detector and a security inspection channel; the device comprises: A coordinate determination module, used to determine the coordinates of at least one reference point, wherein the coordinates of the reference point are the determined center coordinates of the scanned object; an offset determination module, configured to determine the magnification ratio of the scanned object and obtain a focus offset according to the coordinates of the at least one reference point, the position of the light source, and the coordinates of the detector through which the ray of the light source passing through the reference point passes; a changing module, configured to change the focal position of the light source according to the focal offset, so that the light source emits a first X-ray to the scanned object according to the changed focal position; a receiving module, configured to use the detector to receive the first X-ray emitted by the light source to obtain detection data of the first X-ray; and A detection module is used to detect the scanned object according to the detection data of the first X-ray.

15. A security inspection device comprising a light source, a detector, a security inspection channel, a memory and at least one processor; in, The security inspection channel is used to carry the scanned object in linear motion. The light source includes at least one ray source point, the at least one ray source point is arranged on a plane perpendicular to the moving direction of the scanned object, and the offset of the focus of the at least one ray source point is determined according to the position of the scanned object. The detector comprises at least one detection unit, and the at least one detection unit is arranged on a plane parallel to the plane of the light source, and is used to receive X-rays penetrating the scanned object. The memory is used to store instructions. The at least one processor is used to execute instructions stored in the memory to implement the method according to any one of claims 1 to 13.

16. The security inspection device according to claim 15, wherein: The light source further comprises at least one control mechanism, and the at least one control mechanism is used to control the electron beam flow direction of the at least one ray source point to change the focal position of the at least one ray source point.

17. A computer-readable storage medium, applied to a security inspection device, wherein the security inspection device comprises a light source, a detector and a security inspection channel, wherein the computer-readable storage medium stores computer instructions, and when the computer instructions are executed by a processor, the method according to any one of claims 1 to 13 is implemented.

18. A computer program product applied to a security inspection device, wherein the security inspection device comprises a light source, a detector, a slip ring and a security inspection channel, and the computer program product comprises executable instructions, which, when executed by a processor, implement the method according to any one of claims 1 to 13.

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