Pulse frequency modulation

Abstract

In one example, a method is provided for processing data associated with inspecting goods using an inspection system, the inspection system comprising: a radiation source configured to emit N (N being a plurality of) consecutive pulses irradiating the goods at a frequency; and a matrix detector comprising a first column of p1 detectors and at least one second column of p2 detectors, the method comprising: obtaining data related to the current frequency f n Scanning at least a portion of the cargo and associated data, wherein the scanning includes moving the cargo and system with a relative scanning displacement; determining a step speed δ at a predetermined time t; determining whether the determined step speed δ is reliable; if the step speed δ is determined to be reliable, then setting the current frequency f. n Updated to the frequency f n+1 , such that: where F(X) is an increasing function of X such that F(1) = 1, and δ0 is a predetermined step speed; and the output is configured such that the scan is performed at the current frequency with the updated frequency as the current frequency.

Description

Technical Field

[0001] This invention relates to, but is not limited to, methods for processing data associated with inspecting goods using an inspection system. The invention also relates to associated controllers and computer programs or computer program products. Background Technology

[0002] Radiography employs a radiation source placed on one side of the object to be scanned and a detector on the opposite side of the object. Radiography is produced by measuring the radiation transmitted through the object and striking the detector. The projection of the beam onto the object expands from narrow at the radiation source to wide at the detector. The radiation is collimated to just cover the detector to reduce the amount of scattered radiation and dose footprint in the measurement.

[0003] Typically, high-energy X-ray scanners use pulsed X-ray sources. Commercially available linear accelerators (2019) have a maximum pulse frequency range from 400 to 1000 Hz. Most sources are dual-energy to achieve atomic-number identification.

[0004] To scan an object, such as a truck, there is relative motion between the source detector and the truck. In entrance or train scanner applications, the cargo moves while the source and detector remain stationary.

[0005] Unlike continuous sources, pulsed sources produce a snapshot of collimated radiation that strikes an object and is transmitted to a detector.

[0006] In some examples, such as a truck being driven through an entrance X-ray scanner or a railcar passing through a train scanner, the relative velocity may differ from the rated scan velocity. If the relative velocity is too high compared to the rated scan velocity, parts of the object may not be irradiated. If the relative velocity is too low compared to the rated scan velocity, parts of the object may be irradiated multiple times, and the dose to the cargo and to the environment may increase. Due to beam divergence, the lack of adequate irradiation coverage near the source may be greater, and overlap near the detector may be greater.

[0007] Some inspection systems use external speed sensors to determine relative speed. Summary of the Invention

[0008] Aspects and embodiments of the invention are set forth in the appended claims. These and other aspects and embodiments of the invention are also described herein. Attached Figure Description

[0009] Embodiments of this disclosure will now be described by way of example with reference to the accompanying drawings, in which:

[0010] Figure 1 A flowchart illustrating an example method according to this disclosure is shown schematically;

[0011] Figure 2 An example inspection system for inspecting goods according to this disclosure is illustrated schematically;

[0012] Figure 3 An example matrix detector according to this disclosure is illustrated schematically;

[0013] Figure 4 A flowchart illustrating an example method for determining pace δ at a predetermined time t is shown schematically according to this disclosure.

[0014] Figure 5 The diagram illustrates the apparent displacement Δ between the image in column p1 and the image in another column p3;

[0015] Figures 6A to 6F The diagram schematically illustrates the relative motion of five objects of cargo with six pulses between them and a matrix detector comprising five columns.

[0016] Figures 7A to 7F The illustration represents the corresponding to respectively Figures 6A to 6F The pulse is measured on the matrix detector;

[0017] Figures 8A to 8E It schematically represents the target Figures 7A to 7F Images of each column of a matrix detector with six pulses;

[0018] Figure 9 An example inspection system is shown, comprising an example controller configured to at least partially perform methods according to any aspect of this disclosure; and

[0019] Figure 10 An example controller configured to work with the inspection system is illustrated in more detail.

[0020] In the accompanying drawings, similar elements have the same reference numerals. Detailed Implementation

[0021] Overview

[0022] Embodiments of this disclosure provide a method for inspecting goods using an inspection system. The inspection may include a radiation source configured to emit radiation at a current frequency f. n The system emits N (where N is a plurality of pulses) consecutive pulses. The inspection system may also include a detector matrix comprising multiple detector columns. The method may include obtaining the pulse at the current frequency f. nThe generated inspection data can be used to generate images for at least some columns of the detector matrix. The same area of ​​the cargo can be imaged through several columns but at different times. The step rate δ between the generated images can be determined based on the delay between two consecutive columns. The frequency of the radiation source can be updated based on the generated step rate δ, allowing scanning to be performed at the updated frequency.

[0023] The claimed embodiments of the invention maintain the inspection dose by controlling the frequency of the radiation source, thereby enabling optimized image quality regardless of the relative speed between the cargo and the inspection system.

[0024] Alternatively or additionally, even where the relative speed between the cargo and the inspection system may differ from the rated scanning speed, the claimed embodiments of the invention enable inspection of the entire cargo by controlling the frequency of the radiation source.

[0025] Alternatively or additionally, claimed embodiments of the invention enable the updating of the radiation source frequency without requiring the relative velocity between the cargo and the inspection system. Alternatively or additionally, claimed embodiments of the invention enable the updating of the radiation source frequency based on a step speed δ rather than on the obtained relative velocity between the cargo and the inspection system.

[0026] Alternatively or additionally, in the claimed embodiments of the invention, frequency adjustment is performed using data from actual scans of the cargo, taking into account the cargo's depth—not the case when using an external speed sensor. Alternatively or additionally, in the claimed embodiments of the invention, frequency adjustment allows for obtaining inspection images with less distortion and better quality compared to using an external speed sensor.

[0027] Alternatively or additionally, claimed embodiments of the invention enable the frequency of the radiation source to be updated to a higher frequency when needed, so that all portions of the cargo are irradiated. Alternatively or additionally, claimed embodiments of the invention enable the frequency of the radiation source to be updated to a lower frequency when needed, so that portions of the cargo that are irradiated multiple times are substantially minimized, for example, preferably substantially minimized to the portion near the matrix detector.

[0028] Detailed description of exemplary embodiments

[0029] Figure 1 A flowchart illustrating an example method 100 according to this disclosure is shown schematically. Figure 2 An example inspection system 200 for inspecting goods 300 according to this disclosure is illustrated schematically.

[0030] exist Figure 2 In the example, the inspection system 200 includes a radiation source 201 configured to emit N (N being a plurality of) consecutive pulses 400 at a frequency f to irradiate the cargo 300. The inspection system 200 also includes a matrix detector 202 comprising a first column of p1 detectors and at least one second column of p2 detectors.

[0031] The inspection of goods 300 by inspection system 200 involves scanning goods 300. For example... Figure 2 As shown, scanning involves moving the cargo 300 and system 200 along the scanning direction (OX) with a relative scanning displacement. For clarity, in Figure 2 In the example, cargo 300 is shown as stationary relative to the ground, and system 200 is shown as moving along the direction (OX) to the right of the figure for three pulses 400 (referred to as pulses 401, 402, and 403). It should be understood that system 200 may be stationary relative to the ground, and cargo 300 may move along the direction (OX) to the left of the figure during the scan.

[0032] Matrix detector 202 is also schematically represented in Figure 3 In. Figure 2 and Figure 3 In the example, the matrix detector 202 has a total width W in the scanning direction (OX) and includes ten columns p1, p2, ..., p m , where m = 10, extends perpendicular to the scanning direction (OX), i.e., along the direction (OY). Other values ​​of m can be envisioned, and it should be understood that the development of this disclosure will also be applicable to matrix detectors comprising only two columns (i.e., m = 2), or to matrix detectors comprising any number of columns m such that m > 2. If w is the number of columns p per column i The width of (i = 1…m) is then W, which is the total width of matrix detector 202, such that:

[0033] W = mw

[0034] Due to the relative movement between the goods 300 and the inspection system 200 during the inspection, such as Figure 2 As shown, system 200 travels a distance λ along the scanning direction (OX) between two pulses 400 emitted by radiation source 201. In some cases, i.e., for a specific frequency corresponding to a given relative velocity, the travel distance can be a distance λ. max , so that:

[0035]

[0036] Where: W is the total width W of the matrix detector 202 with m columns in the scanning direction;

[0037] d is the distance between radiation source 201 and cargo 300 relative to the first plane 302 of radiation source 201; and

[0038] L is the distance between radiation source 201 and matrix detector 202.

[0039] exist Figure 2 In the middle, the distance λ between the two pulses max (That is, the time intervals within the pulses) can correspond to the desired situation where the specific frequency of the radiation source 201 and the given relative velocity cause all portions of the cargo 300 to be irradiated by pulses 401, 402, and 403, and cause portions of the cargo that are irradiated multiple times (i.e., due to the overlap of pulses 401, 402, and 403, see...) Figure 2 The hash region in the system is substantially minimized, preferably substantially minimized to the region near matrix detector 202. The distance λ traveled by system 200 between two pulses (i.e., the time interval within a pulse) is... max Can be compared with walking speed δ min The step speed δ is related to the number of pulses per column. min The system traveled a distance λ' corresponding to system 200. max The number of pulses 400 (column number) makes:

[0040]

[0041] as well as,

[0042] walking speed δ min It has dimensions for each pulse, which is the time interval of each distance (i.e., the reciprocal of the velocity).

[0043] Figure 2 distance λ max and walking speed δ min This is just an example, and other examples of distance λ and step speed δ can be envisioned.

[0044] Return to reference Figure 1 Method 100 includes: at S1, obtaining the frequency f at the current frequency f n Data associated with at least one portion 301 of the cargo 300 is scanned; and at S2, the step speed δ at a predetermined time t is determined. Step S2 will be described in further detail later in this disclosure.

[0045] Method 100 also includes:

[0046] At point S3, determine whether the determined step speed δ is reliable;

[0047] At S4, if the step speed δ determined at S3 is reliable, then the current frequency f is...n Updated to the frequency f n+1 , so that:

[0048] Where F(X) is an increasing function of X such that F(1) = 1, and

[0049] Where F(X) is an increasing function of X such that F(1) = 1; and

[0050] δ0 is the predetermined pace; and

[0051] At S5, output data to perform a scan so that the frequency to be updated is the current frequency.

[0052] In some examples, the function F(X) can be equal to X, and the frequency of updates is f. n+1 It could be like this:

[0053]

[0054] In some examples, δ0 can be the δ mentioned above. min .

[0055] Return to reference Figure 1 Method 100 includes: at S5, outputting data to perform a scan so that the updated frequency is the current frequency. The output data may include command data to trigger the radiation source 201 at the updated frequency.

[0056] Figure 4 The flowchart of an example method S2 for determining the step speed δ at a predetermined time t is schematically shown.

[0057] exist Figure 4 In the process, determining the step speed δ at the predetermined time t at point S2 includes:

[0058] At point S21, select quantity q;

[0059] At S22, using the data obtained at S1, and using q consecutive pulses emitted before the predetermined time t, a first image of the cargo is generated for the first column p1 of the matrix detector 202;

[0060] At S23, using the data obtained at S1, and using q consecutive pulses emitted before a predetermined time t, at least one second image of the cargo is generated for at least one second column p2 of the matrix detector 202; and

[0061] At S24, the step speed δ is determined at the predetermined time t using a first image of the cargo at a predetermined time t, at least one second image of the cargo, and a number (p2-p1) corresponding to the number of columns between the first column p1 and at least one second column p2.

[0062] Several methods for determining the step speed δ at S24 will be described in more detail later in this disclosure.

[0063] Before describing the determination of the step rate δ performed at S24, an example of the step rate δ is explained below.

[0064] The step speed δ determined at S2 is clearly derived from at least a portion of cargo 300 from a column p of matrix detector 202. k Passed to the next column p in matrix detector 202 k+1 The required number of pulses (this number does not have to be an integer) is associated with this. For example... Figure 5 As shown, in column p k And another column p l The apparent displacement Δ (expressed in pulse number) in the scanning direction between the images is as follows:

[0065] Δ=(p l -p k )δ

[0066] Among them, Figure 5 In the example, l equals 3 and k equals 1.

[0067] Reference Figures 6A to 8E Let's explain the walking speed δ in more detail.

[0068] Figures 6A to 6F The diagram schematically illustrates the relative motion of five objects of cargo 300 with respect to matrix detector 202. For six pulses t1, t2, t3, t4, t5, and t6 (corresponding to the selection of q = 6 at S21), matrix detector 202 comprises five columns p1, p2, p3, p4, and p5. Other values ​​of q ≥ 2 can be envisioned. In some examples, the selected number q could be such that:

[0069] 2≤q≤200.

[0070] Figures 7A to 7F The illustration represents the corresponding to respectively Figures 6A to 6C And the measurements on matrix detector 202. Figures 7A to 7F In the diagram, a solid object in a column indicates that the corresponding object is completely contained within that column, while a hash object indicates that the corresponding object overlaps with both columns. A hash object corresponds to the case where the object appears on both columns but with lower contrast—for example, on pulse t1, a triangular object located between columns p1 and p2 will generate signals on columns p1 and p2.

[0071] Figures 8A to 8E It schematically represents the target Figures 7A to 7FThe image of each column of a matrix detector with six pulses (i.e., q = 6). It should be understood that the image generated by column p4 is the same image as the image generated by column p1, with a time shift of two pulses (e.g., t3-t1). Similarly, the image generated by column p5 is also the same image as the image of column p2, with a time shift of two pulses (e.g., t5-t3). Therefore, for three columns (p4-p1 or p5-p2), δ has two pulses (t3-t1 or t5-t3), and δ is as follows:

[0072]

[0073] As explained in more detail below, the determined pace δ can be compared with the predetermined pace δ0.

[0074] If δ is less than δ0 (e.g., it takes δ = two pulses to clearly move one column of the image instead of δ0 = five pulses), then the frequency of the radiation source is too low for the relative speed of the scan and needs to be increased. If δ is greater than δ0 (e.g., it takes δ = seven pulses to clearly move one column of the image instead of δ0 = five pulses), then the frequency of the radiation source is too high for the relative speed of the scan and needs to be decreased.

[0075] In the example above, δ0 can be equal to 5, but other values ​​are conceivable. In some examples, the predetermined pace δ0 can be like this:

[0076]

[0077] Where d is the distance between the radiation source 201 and the cargo relative to the first plane 302 of the radiation source 201.

[0078] L is the distance between radiation source 201 and matrix detector 202.

[0079] m is the number of columns in matrix detector 202, and q is the number of selected consecutive pulses.

[0080] q is the number of consecutive pulses selected to generate the image.

[0081] The above inequality will now be explained in more detail.

[0082] In the above inequality, the ratio L / d takes into account the corresponding depth positions of the cargo and the matrix detector relative to the radiation source. For simplicity, let the ratio L / d be equal to 1 (i.e., the cargo is located at the same level as the matrix detector).

[0083] When δ is less than 1 / m, it means that the object in the cargo has moved more than m columns in one pulse. Therefore, the object in the cargo can only be seen once, and only in a single image (a single image out of m images generated by columns), which makes any estimation of δ impossible.

[0084] When δ is greater than q, within q pulses, the cargo object will not have enough time to move from one column of the matrix detector to the next. Therefore, the cargo object will only appear in one image generated by the columns, making it impossible to estimate δ. Therefore, if δ0 is greater than q, the chosen number q must be increased.

[0085] In some examples, the first scan of at least one portion 301 of the cargo utilizes the current frequency f corresponding to the rated maximum frequency f0 of the radiation source. n Execution. The rated maximum frequency f0 can be as follows:

[0086] 100Hz≤f0≤1000Hz

[0087] Other values ​​for f0 are conceivable.

[0088] No update is needed at S4 for each pulse, because the interval between two pulses is on the order of milliseconds, which is too short for a truck or train to significantly change its speed. The step speed δ can be selected from intervals ranging from 25ms to 500ms at its determined predetermined time t.

[0089] The determination of the step rate δ performed at S24 will now be described in more detail.

[0090] In some examples, determining the step speed δ at S24 may include:

[0091] Image cross-correlation techniques are used to determine the time shift δ between a first image of the cargo and at least one second image of the cargo at a predetermined time t. t ;as well as

[0092] The determined time shift δ t Divide by the number corresponding to the number of columns between the first column p1 and at least one second column p2 (p2-p1).

[0093] Determining the step speed δ at S24, including using image cross-correlation, can be achieved by performing the image cross-correlation technique on the generated image pairs. In some examples, the generated image pairs may include: a first image of the goods for the first column p1 of the matrix detector 202, and an image of the goods for the last column p1 of the matrix detector. m The second image of the goods.

[0094] Cross-correlation of images is known to those skilled in the art for determining displacements in an image sequence. An example of cross-correlation techniques will now be briefly described.

[0095] Fourier transform can be used to locally find the displacement vectors between images. If and It corresponds to columns p1 and p m The two images, then and It is a 2D Fourier transform.

[0096] The normalized cross-power spectrum R can be calculated such that:

[0097]

[0098] Here, ° is the entry-wise product of matrices, and * is the complex conjugate.

[0099] if and It is a time shift (δ) offset in the scanning direction (OX) t If the same image is used, then the cross-power spectrum is:

[0100]

[0101] To obtain the cross-correlation, we can determine that the current value is (δ). t The inverse Fourier transform of the cross-power spectrum of the Dirac delta function located in the region. Find (δ... t It may be necessary to calculate R, and the maximum value of the Fourier transform of R can be located.

[0102] For a given region of displacement, the above method can be applied to each pixel (x, y) within a small square window (n×n pixels) centered on the pixel, and the result can be considered as a local displacement (δ). t (x, y)).

[0103] The obtained time shift δ t Divide by (p) m -p1) to obtain the step speed δ.

[0104] In some cases, determining the step speed δ at S24 involves the use of energy minimization techniques, which are also known to those skilled in the art. Examples of energy minimization techniques will now be briefly described.

[0105] An energy minimization technique can be performed to minimize the energy function E(δ) such that:

[0106]

[0107] in It is the first column p used in the matrix detector k The first image of the goods, image Including pixels (i, j) in the i-th row and j-th column,

[0108] It is the second column p used in the matrix detector l The second image of the goods, image Including pixels (i, j) in the i-th row and j-th column,

[0109] α(p k ,p l ) is p k and p l The strictly positive weighted function, and

[0110] m is the number of columns in the matrix detector.

[0111] Return to reference Figure 1 S3 includes determining whether the determined step rate δ is reliable. In some cases, especially when m images generated using q pulses do not exhibit large horizontal gradients (e.g., for locally uniform content), the determined step rate δ may be unreliable.

[0112] In some examples, determining whether the pace δ is reliable at S3 may include comparing a standard C with a predetermined standard threshold C. min Comparison makes:

[0113]

[0114] Among them (I) k (i,j+1)-I k (i,j) is the image I between column j and (j+1). k The horizontal gradient in the middle.

[0115] S3 may also include determining the reliability of δ when C is the following:

[0116] C>C min

[0117] Value C min It can be determined using experimental methods.

[0118] When using energy minimization techniques to determine the step speed δ at S24, is it reliable to use the energy function E to determine the step speed δ at S3? This could include considering the difference |E|. min -E(0)│and the predetermined energy threshold E threshold The steps for comparison.

[0119] Emin It is the value of energy E at its minimum, such that E(δ) = E min And E(0) is the initial value of the energy corresponding to no step speed.

[0120] S3 can also include when |E min When -E(0)│ is the following formula, the step speed δ is reliably determined:

[0121] │E min –E(0)│>E threshold

[0122] The value E can be determined experimentally. threshold .

[0123] Return to reference Figure 1 If the step speed δ is determined to be unreliable at S3, then method 100 includes maintaining the frequency of the radiation source at the current frequency f at S6. n This frequency is not updated.

[0124] In some cases, radiation source 201 can be configured to emit pulses in both low-energy and high-energy modes, for example, to achieve atomic number identification.

[0125] In this case, determining the step speed δ at S2 can include:

[0126] Determine the step speed δ for the lower energy mode LM ;

[0127] Determine the step speed δ for higher energy modes HM ;as well as

[0128] The step speed δ for lower energy modes was determined experimentally. LM and the step speed δ for the higher energy mode HM The weighted average value is used to determine the step speed δ.

[0129] Alternatively or additionally, determining the step speed δ at S2 may include:

[0130] The data obtained at S1 is processed to obtain further data, including data associated with lower energy modes and data associated with higher energy modes;

[0131] Further data associated with lower energy patterns will be converted into data corresponding to higher energy patterns; and

[0132] The cadence δ was determined by using the converted data and further data associated with higher energy patterns.

[0133] In some examples, transforming further obtained data associated with lower energy patterns into data corresponding to higher energy patterns may include generating a histogram showing the occurrence of pixels in the examined data that have: (i) a given intensity associated with higher energy pattern data; and (ii) a given intensity associated with lower energy pattern data. The generated histogram can be used to associate each given intensity associated with lower energy pattern data with the corresponding most frequent intensity associated with higher energy pattern data. A transformation table mapping the associated intensities can be generated. The transformation table can be used to determine the transformed intensity corresponding to the higher energy pattern data by transforming the intensity associated with the lower energy pattern data.

[0134] Examples of this method are also disclosed in GB2003046.6, the entire contents of which are incorporated herein by reference.

[0135] In the case of including both lower and higher energy modes, determining the step speed δ at S2 may include generating a first image and at least one second image using 2q consecutive pulses emitted before a predetermined time t. Alternatively or additionally, determining the step speed δ at S2 may be performed with a period halved compared to the period in the case where the radiation source is configured to emit pulses in a single energy mode.

[0136] As described below, in some examples, the determination of the step speed δ can be performed by averaging to obtain a smooth estimate.

[0137] In some examples, determining the step speed δ at S2 can be performed in several steps using K time points prior to the predetermined time t, where K is multiple and can include:

[0138] Select the current scheduled time t;

[0139] Using the obtained data, and using q consecutive pulses emitted before the selected current predetermined time t, a first image of the cargo for the first column p1 of the matrix detector is generated;

[0140] Using the obtained data, and using q consecutive pulses emitted before the selected current predetermined time t, generate at least one second image of the cargo for at least one second column p2 of the matrix detector;

[0141] Determine the current pace at the current predetermined time t;

[0142] Determine whether the determined step speed δ is reliable;

[0143] If the step speed δ is determined to be reliable, then store the determined current step speed δ at the current predetermined time t;

[0144] For K time points (K being multiple), repeat the following operation:

[0145] A first image and at least one second image are generated using q consecutive pulses emitted before each of multiple current times t.

[0146] Determine the current walking speed δ.

[0147] Determine if the current pace δ is reliable, and

[0148] Storage reliability step rate δ.

[0149] Therefore, the step speed δ at a predetermined time t can be determined by averaging the step speeds δ of multiple stored data.

[0150] In some cases, the q pulses at time t can overlap with the q pulses at time t-1.

[0151] If the q pulses at time t do not overlap with the q pulses at time t-1, then to limit the time between two frequency updates, the K time points (K being multiple) can be as follows:

[0152] 2≤K≤10.

[0153] In some examples, method 100 may also include performing a scan of the goods. This method may be performed when the goods are within a predetermined scan area.

[0154] Figure 9 A controller 5 is shown, configured to at least partially perform method 100 according to any aspect of this disclosure. The controller 5 is configured to cooperate with inspection system 200 of any aspect of this disclosure.

[0155] exist Figure 9 The goods to be inspected, 300, are located in container 400. Figure 9 The inspection system 200 can be configured to generate inspection data in accordance with any aspect of this disclosure.

[0156] The controller 5 can be configured to receive inspection data, for example, via a communication network 6, which may be wired and / or wireless.

[0157] As explained in more detail below, controller 5 typically includes at least a processor and memory in order to execute example methods according to this disclosure.

[0158] like Figure 10 As shown, the controller 5 may include an interface board 51 configured to cooperate with the front-end electronics of the radiation source 201 and / or the matrix detector 202. The controller 5 may also include a processor 52 configured to preprocess data associated with the scan and / or generate the first image and at least one second image disclosed herein.

[0159] In some examples, interface board 51 can be configured for each of N (N being a plurality of) consecutive pulses:

[0160] The acquired data is transmitted to processor 52; and / or

[0161] Based on the current frequency f of radiation source 201 n The front-end electronic equipment of the control matrix detector 202 acquires data; and / or

[0162] Based on the current frequency f n Control the generation of continuous pulses by radiation source 201.

[0163] Before the front-end electronics of the matrix detector 202 acquire data for the next time, the processor 52 can send the frequency value to the interface board 51.

[0164] Alternatively or additionally, the controller 5 may also include a memory 53 storing instructions that, when executed by the processor 52, enable the processor to perform methods according to any aspect of this disclosure.

[0165] Alternatively or additionally, processor 52 may be further configured to determine the step speed δ and frequency update in real time or near real time (in parallel with preprocessing) and transmit the frequency update to interface board 51.

[0166] In some examples (not shown in the figures), the processor can be located remotely from the interface board. In this case, the interface board can also be configured to transmit data to the processor via an Ethernet-based communication link. This architecture can be used when the relative speed of the goods does not change too rapidly (e.g., when the goods are on a train).

[0167] In some examples (not shown in the figures), the processor may include an onboard processor located on the interface board. In this case, the onboard processor may include a Field Programmable Gate Array (FPGA). The onboard processor can be configured to directly compute frequency updates. Frequency updates can be performed by triggering the radiation source without communication lag. The processor can have sufficient memory to temporarily store the required data. This architecture can be used when the relative speed of the cargo may change rapidly.

[0168] exist Figure 9 In the example shown, communication server 8 can be configured to communicate with system 200 and / or controller 5 via a communication network 7, which can be wired and / or wireless. In some examples, communication server 8 can be configured to perform the functions of a remote data management system. In some examples, server 8 may include a database. The database can be configured to store inspection data and / or other data for any aspect of this disclosure.

[0169] Similarly, controller 5 can be configured to store inspection data and / or other data for any aspect of this disclosure.

[0170] Changes and modifications

[0171] It should be understood that examining radiation sources may include other radiation sources, such as ionizing radiation sources, like gamma rays or neutrons, as non-limiting examples.

[0172] As one possibility, a computer program, computer program product, or computer-readable medium is provided, comprising computer program instructions to cause a programmable computer to perform any or more of the methods described herein. In the example implementation, at least some portions of the activities associated with controller 5 herein may be implemented in software. It should be understood that, if desired, the software components of this disclosure may be implemented in ROM (read-only memory). If desired, the software components may typically be implemented in hardware using conventional techniques.

[0173] In some examples, components of controller 5 and / or communication network 6 and / or 7 may use dedicated applications and hardware.

[0174] As will be understood by those skilled in the art, server 8 and / or controller 5 should not be construed as a single entity, but rather as a physical and / or virtual device comprising at least a processor and memory, which may be included in one or more servers, which may be located in a single location or may be geographically dispersed to form a distributed network (such as a “server farm”, for example using wired or wireless technology).

[0175] In some examples, one or more memory elements (e.g., the memory of a database and / or processor) may store data used for the operations described herein. This includes memory elements capable of storing software, logic, code, or processor instructions that are executed to perform the activities described in this disclosure.

[0176] A processor can execute any type of instructions associated with data to perform the operations detailed herein. In one example, a processor can transform an element or article (e.g., data) from one state or thing to another. In another example, the activities outlined herein can be implemented with fixed logic or programmable logic (e.g., software / computer instructions executed by a processor), and the elements identified herein can be some type of programmable processor, programmable digital logic (e.g., field-programmable gate array (FPGA), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM)), ASIC including digital logic, software, code, electronic instructions, flash memory, optical disc, CD-ROM, DVD ROM, magnetic card or optical card, other types of machine-readable media suitable for storing electronic instructions, or any suitable combination of the above.

[0177] Communication network 6 and communication network 7 can form only one network.

[0178] The data received by controller 5 can typically be received over a range of possible communication networks 6 and / or 7, including at least: satellite-based communication networks; cable-based communication networks; telephone-based communication networks; mobile phone-based communication networks; Internet Protocol (IP) communication networks; and / or computer-based communication networks.

[0179] In some examples, communication networks 6 and / or 7 and / or controller 5 may include one or more networks. Networks may be provided in any form, including but not limited to local area networks (LANs), wireless local area networks (WLANs), virtual local area networks (VLANs), metropolitan area networks (MANs), wide area networks (WANs), virtual private networks (VPNs), intranets, extranets, any other suitable architecture or system, or any combination of the above that facilitates communication within the network.

[0180] The inspection system 200 may be mobile and transportable from one location to another (the system may include a motor vehicle). Alternatively or additionally, the inspection system may be stationary relative to the ground and not move.

[0181] The radiation source for inspection may include an X-ray generator. The energy of the X-rays can be between 100 keV and 15 MeV, and the dose can be between 2 mGy and 20 Gy (Gray). For mobile inspection systems, with steel penetration capabilities, such as between 40 mm and 400 mm, typically 300 mm (12 inches), the power of the X-ray source can be, for example, between 100 keV and 9.0 MeV, typically 2 MeV, 3.5 MeV, 4 MeV, or 6 MeV. For mobile inspection systems, the dose can be, for example, between 20 mGy and 120 mGy. For static inspection systems, with steel penetration capabilities, such as between 300 mm and 450 mm, typically 410 mm (16.1 inches), the power of the X-ray source can be, for example, between 4 MeV and 10 MeV, typically 9 MeV. For static inspection systems, the dose can be 17 Gy.

[0182] In addition to other conventional electrical components, the detector may include radiation detection lines, such as X-ray detection lines. The detector may also include other types of detectors, such as optional gamma and / or neutron detectors, suitable for detecting the presence of radioactive gamma and / or neutron-emitting materials within the container simultaneously with X-ray inspection. For mobile inspection systems, the detector may also include an electro-hydraulic boom that can operate in a retracted position in transport mode and in the inspection position. The boom may be operated by a hydraulic actuator (e.g., a hydraulic cylinder). For static inspection systems, the detector may also include a structure and / or bench. The detection line may be mounted on the boom or structure and / or bench, facing the source on the opposite side of the container.

[0183] To inspect containers, the system may include motion-generating devices that allow the system to be moved while the containers remain stationary (this mode is sometimes referred to as "scanning" mode). Alternatively or additionally, the motion-generating devices may allow the containers to move while the system remains stationary relative to the ground. In some embodiments, the throughput, i.e., the number of containers and / or images per unit time, may be 20 to 30 images per hour. Alternatively or additionally, in "pass-through" mode, the system does not include motion-generating devices, and the containers move relative to the system while the system remains stationary relative to the ground. In embodiments, the throughput in pass-through mode may be higher than that in scanning mode, and in the case of inspecting passing trains, it may be, for example, 50 to 200 images per hour, or even 50 to several thousand images per hour (e.g., throughput exceeding 1000 images per hour).

[0184] The above embodiments should be understood as illustrative examples, and other embodiments are contemplated. It should be understood that any feature described with respect to any embodiment may be used alone or in combination with other described features, and may also be used in combination with one or more features of any other embodiment, or in any combination with any other embodiment. Furthermore, equivalents and modifications not described above may be employed without departing from the scope of the invention as defined in the appended claims.

Claims

1. A method for processing data associated with inspecting goods using an inspection system. The inspection system includes: A radiation source, configured to emit N consecutive pulses at a frequency to irradiate the cargo, where N is a plurality of pulses. A matrix detector, comprising a first column p1 detector and at least one second column p2 detector. The method includes: Obtain and at the current frequency f n Scanning associated data on at least a portion of the cargo, wherein the scanning includes moving the cargo and the system with a relative scan displacement; Determine the walking speed δ at a predetermined time t, including: Choose the quantity q. Using the obtained data, and q consecutive pulses emitted before the predetermined time t, a first image of the cargo is generated for the first column p1 of the matrix detector. Using the obtained data, and using the q consecutive pulses emitted before the predetermined time t, at least one second image of the cargo is generated for the at least one second column p2 of the matrix detector, and At the predetermined time t, the step speed δ is determined using the first image of the cargo, the at least one second image of the cargo, and the number (p2-p1) corresponding to the number of columns between the first column p1 and the at least one second column p2; Determine whether the determined step speed δ is reliable; If the step speed δ is reliably determined, then the current frequency f is... n Updated to the frequency f n+1 , so that: Where F(X) is an increasing function of X such that F(1) = 1, and δ0 is the predetermined pace; and The output is configured such that the scan is performed at the current frequency, which is the frequency of the update.

2. The method of claim 1, wherein the scanning of the at least portion of the cargo is performed at a current frequency f corresponding to the rated maximum frequency f0 of the radiation source. n And then it was executed.

3. The method according to claim 1, wherein the function F(X) is equal to X.

4. The method according to any one of claims 1 to 3, wherein determining the step speed δ comprises: The time shift δ between the first image of the cargo and the at least one second image of the cargo at the predetermined time t is determined using image cross-correlation techniques. t ; as well as The determined time shift δ t Divide by the number (p2-p1) corresponding to the number of columns between the first column p1 and the at least one second column p2.

5. The method of claim 4, wherein the image cross-correlation technique is performed on the generated image pairs, optionally, wherein the generated image pairs comprise: The first image of the cargo for the first column p1 of the matrix detector; as well as For the last column p of the matrix detector m The second image of the goods.

6. The method according to any one of claims 1 to 3, wherein determining the step speed δ comprises using an energy minimization technique, said energy minimization technique being performed to minimize the energy function E(δ), such that: in It is for the first column p of the matrix detector k The first image of the goods, the image Including pixels (i, j) in row i and column j, It is for the second column p of the matrix detector l A second image of the goods, the image Including pixels (i, j) in row i and column j, yes p k and p l The strictly positive weighted function, and m is the number of columns in the matrix detector.

7. The method according to claim 1, wherein the predetermined step speed δ0 is as follows: Where d is the distance between the radiation source and the cargo relative to the first plane of the radiation source. L is the distance between the radiation source and the matrix detector, and m is the number of columns in the matrix detector, and q is the number of selected consecutive pulses.

8. The method of claim 1, wherein the selected quantity q is as follows: 2 ≤ q ≤ 200。 9. The method of claim 1, further comprising if the step speed δ is determined to be unreliable: Maintain the frequency at the current frequency f n .

10. The method of claim 1, wherein determining whether the step speed δ is reliable comprises: Compare standard C with the predetermined standard threshold C min The comparison makes: in( The image I between column j and (j+1) k The horizontal gradient in; and The step speed δ is reliably determined when C satisfies the following formula: C>C min Where C min The value of was determined experimentally.

11. The method of claim 6, wherein determining whether the step speed δ is reliably executed using the energy function E(δ) comprises the following steps: The difference |E min -E(0)│and the predetermined energy threshold E threshold Compare; as well as When |E min When -E(0)│ satisfies the following formula, the step speed δ is reliably determined: │E min – E(0)│> E threshold Where E threshold The value of was determined experimentally. E min It is the value of the energy E at its minimum, such that E(δ) = E min ,as well as E(0) is the initial value of the energy corresponding to no step speed.

12. The method of claim 1, wherein the radiation source is configured to emit the pulse in a low-energy mode and a high-energy mode, and wherein determining the step speed δ comprises: Determine the step speed δ for the lower energy mode. LM ; Determine the step speed δ for the higher energy mode. HM ; as well as The step speed δ determined experimentally for the lower energy mode was used. LM and the step speed δ for the higher energy mode HM The weighted average value is used to determine the step speed δ.

13. The method of claim 1, wherein the radiation source is configured to emit the pulse in a low-energy mode and a high-energy mode, and wherein determining the step speed δ comprises: The obtained data is processed to obtain further data, including data associated with the lower energy mode and data associated with the higher energy mode; The data further obtained and associated with the lower energy mode is converted into data corresponding to the higher energy mode; as well as The step speed δ is determined by using the converted data and the further acquired data associated with the higher energy mode.

14. The method of claim 12 or 13, wherein determining the step speed δ further comprises generating the first image and the at least one second image using 2q consecutive pulses emitted before the predetermined time t.

15. The method of claim 12 or 13, wherein determining the step speed δ to be halved compared to the period when the radiation source is configured to emit the pulse in a single-energy mode is performed.

16. The method of claim 1, wherein determining the step speed δ is performed in several steps using K time points prior to the predetermined time t, where K is a plurality of times, and includes: Select the current scheduled time t; Using the obtained data, and using the q consecutive pulses emitted before the selected current predetermined time t, the first image of the cargo is generated for the first column p1 of the matrix detector; Using the obtained data, and using the q consecutive pulses emitted before the selected current predetermined time t, the at least one second image of the cargo is generated for the at least one second column p2 of the matrix detector; At the current predetermined time t, the current pace δ is determined using the first image of the cargo at the current predetermined time t, the at least one second image of the cargo, and the quantity (p2-p1) corresponding to the number of columns between the first column p1 and the at least one second column p2; Determine whether the determined step speed δ is reliable; If the step speed δ is reliably determined, then the current step speed δ determined at the current predetermined time t is stored. For the K time points, where K can be multiple, repeat the following operation: The first image and the at least one second image are generated using the q consecutive pulses emitted before each of a plurality of current predetermined times t. Determine the current step speed δ. Determine whether the current step speed δ is reliable, and Store the reliable step speed δ; as well as The step speed δ at the predetermined time t is determined by averaging the step speeds of the multiple stored steps.

17. The method of claim 16, wherein the q consecutive pulses at time t overlap with the q consecutive pulses at time t-1, or in, The q consecutive pulses at time t do not overlap with the q consecutive pulses at time t-1, and wherein the K times satisfy the following equation, where K is a plurality of times: 2≤K≤10。 18. The method of claim 1, wherein outputting the data comprises outputting command data to trigger the radiation source at the updated frequency; or It also includes performing the scan.

19. A controller configured to cooperate with an inspection system for inspecting goods. The inspection system includes: A radiation source, configured to emit N consecutive pulses at a frequency to irradiate the cargo, where N is a plurality of pulses. A matrix detector, comprising a first column p1 detector and at least one second column p2 detector. The controller is configured to: Obtain and at the current frequency f n Scanning associated data on at least a portion of the cargo, wherein the scanning includes moving the cargo and the system with a relative scan displacement; Determine the walking speed δ at a predetermined time t, including: Choose the quantity q; Using the obtained data, and using q consecutive pulses emitted before the predetermined time t, a first image of the cargo is generated for the first column p1 of the matrix detector; Using the obtained data, and using the q consecutive pulses emitted before the predetermined time t, at least one second image of the cargo is generated for the at least one second column p2 of the matrix detector; and At the predetermined time t, the step speed δ is determined using the first image of the cargo, the at least one second image of the cargo, and a number (p2 - p1) corresponding to the number of columns between the first column p1 and the at least one second column p2; and Determine whether the determined step speed δ is reliable; If the step speed δ is reliably determined, then the current frequency f is... n Updated to the frequency f n+1 , so that: Where F(X) is an increasing function of X such that F(1) = 1, and δ0 is the predetermined pace; and The output is data that causes the scan to be performed at the current frequency, which is the frequency of the update.

20. The controller of claim 19, configured to perform the method of any one of claims 2 to 18.

21. The controller according to claim 19 or 20, comprising: An interface board configured to cooperate with the front-end electronics of the radiation source and / or the matrix detector; as well as A processor configured to preprocess the data associated with the scan and / or generate the first image and the at least one second image.

22. The controller of claim 21, wherein the interface board is configured for each of the N consecutive pulses, where N is a plurality of pulses: The acquired data is transmitted to the processor; and / or Based on the current frequency f n Controls the data acquisition performed by the front-end electronic device; and / or Based on the current frequency f n The generation of the continuous pulses generated by the radiation source is controlled.

23. The controller of claim 21, further comprising a memory storing instructions that, when executed by the processor, enable the processor to perform the method of any one of claims 1 to 18.

24. The controller of claim 21, wherein the processor is located remotely from the interface board, optionally, wherein the interface board is further configured to transmit data to the processor via an Ethernet-based communication link, or The processor includes an onboard processor located on the interface board, and optionally, the onboard processor includes a field-programmable gate array (FPGA).

25. A computer program or computer program product comprising instructions that, when executed by a processor, enable the processor to perform the method according to any one of claims 1 to 18 or to control the controller according to any one of claims 19 to 24.

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