A multi-band imaging method and system based on an ARM+DSP+FPGA heterogeneous platform

Abstract

The application discloses a multi-band imaging method and system based on an ARM+DSP+FPGA heterogeneous platform and relates to the field of radar system imaging. The method comprises the following steps: S1, after a signal processor is powered on, a FPGA is controlled to periodically perform pulse compression on input sampling data to generate pulse compression and store the pulse compression in a corresponding circular buffer space; when the FPGA receives an imaging start instruction, an srio interrupt carrying a doorbell information is sent to an ARM, and the doorbell information is used to indicate the position of the pulse compression of the current period in the circular buffer space; S2, when the ARM receives the srio interrupt, the wave band and the position of the current pulse compression are determined according to the doorbell information, and the DSP is triggered to start imaging; S3, when the DSP receives the start imaging instruction, the pulse compression in the circular buffer space is read, the pulse compression of multiple wave bands is imaged and accumulated, and multi-band imaging is completed. The method is used for solving the problem that the existing multi-band imaging system cannot meet the real-time imaging requirement.

Description

Technical Field

[0001] This application relates to the field of radar system imaging technology, and in particular to a multi-band imaging method and system based on an ARM+DSP+FPGA heterogeneous platform. Background Technology

[0002] Radar is an active detection device that detects and tracks targets by emitting and receiving electromagnetic waves. However, due to the influence of the external environment, radar systems are susceptible to interference, which affects their performance and accuracy. Therefore, the research and application of radar anti-jamming technology has always been an important direction in the development of radar technology.

[0003] Traditional single-band imaging detection technology, due to its limited acquisition of scene information, is no longer sufficient for accurate target detection in highly contested combat environments such as strong background interference, strong artificial interference, and strong tactical maneuver interference. Therefore, multi-band imaging terminal guidance technology has attracted widespread attention. Increasing the number of radar signal bands can improve the radar system's anti-electromagnetic interference performance; however, because multi-band systems need to process signals from multiple frequency bands simultaneously, higher demands are placed on real-time performance. Summary of the Invention

[0004] The purpose of this application is to provide a multi-band imaging method and system based on an ARM+DSP+FPGA heterogeneous platform to solve the problem that existing multi-band imaging systems cannot meet the real-time imaging requirements.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] On the one hand, this application provides a multi-band imaging method based on an ARM+DSP+FPGA heterogeneous platform, including:

[0007] S1. After the signal processor is powered on, it controls the FPGA to periodically compress the input sampling data into pulses to generate pulse pressure and stores the pulse pressure in the corresponding loop buffer space. When the FPGA receives the imaging start command, it sends an Srio interrupt carrying doorbell information to the ARM. The doorbell information is used to indicate the position of the pulse pressure in the loop buffer space of the current period.

[0008] S2. When the ARM receives the SRIO interrupt, it determines the current pulse pressure band and location based on the doorbell information and triggers the DSP to start imaging.

[0009] S3. When the DSP receives the start imaging command, it reads the pulse pressure in the circular buffer space, accumulates the pulse pressure of multiple bands, and completes multi-band imaging.

[0010] On the other hand, this application also provides a multi-band imaging system based on an ARM+DSP+FPGA heterogeneous platform, including:

[0011] FPGA is used to control the signal processor to periodically compress the input sampling data into pulses after the signal processor is powered on, and to store the pulses in the corresponding loop buffer space. When the FPGA receives the imaging start command, it sends an ARM interrupt carrying doorbell information to the ARM. The doorbell information is used to indicate the position of the pulse in the loop buffer space of the current period.

[0012] The ARM is used to determine the current pulse pressure band and location based on the doorbell information when the ARM receives an SRI interrupt, and then trigger the DSP to start imaging.

[0013] The DSP is used to read the pulse compression in the circular buffer space after receiving the start imaging command, and to accumulate pulse compression in multiple bands to complete multi-band imaging.

[0014] On the other hand, this application also provides an electronic device,

[0015] A processor; and a memory arranged to store computer-executable instructions, which, when executed, cause the processor to perform the steps of the method as described in any of the preceding claims.

[0016] Based on the above technical solution, this application can achieve the following technical effects:

[0017] This application studies multi-band imaging systems and proposes a multi-band imaging method and system based on an ARM+DSP+FPGA heterogeneous platform. Specifically, an ARM+DSP+FPGA architecture is used as the core processor. The DSP implements the multi-band digital image part, the ARM implements pulse compression transmission, and the FPGA performs pulse compression on the input sampled data, storing the pulse compression results cyclically in the corresponding DDR space and sending an interrupt signal carrying doorbell information to the ARM. This method can fully leverage the advantages of different processors. Utilizing the powerful mathematical computation capabilities of the DSP, the parallel computing capabilities of the FPGA, and the transaction management capabilities of the ARM, the real-time capability of simultaneously acquiring multiple images is greatly improved. Simultaneously, this method provides the software with good scalability, maintainability, and reusability, allowing for flexible implementation of easily changeable parts in the software, and also increasing the system's optimization potential. In terms of implementation, by designing a reasonable timing sequence to complete multi-band imaging, rapid processing and real-time display are achieved, thus ensuring both the real-time performance and processing quality of multi-band imaging. Attached Figure Description

[0018] Figure 1This is a flowchart illustrating a multi-band imaging method based on an ARM+DSP+FPGA heterogeneous platform provided in an embodiment of this application.

[0019] Figure 2 This is a schematic diagram of the ARM+DSP+FPGA imaging timing design provided in one embodiment of this application;

[0020] Figure 3 This is a timing diagram of the imaging accumulation period provided in an embodiment of this application;

[0021] Figure 4 This is a schematic diagram of the FPGA transmit pulse compression buffer address design provided in one embodiment of this application;

[0022] Figure 5 This is a schematic diagram of an ARM design provided in an embodiment of this application;

[0023] Figure 6 This is a schematic diagram of a DSP multi-band imaging design provided in an embodiment of this application. Detailed Implementation

[0024] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present application will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and are not to scale, and are only used to facilitate and clarify the illustration of the embodiments of the present application.

[0025] It should be noted that, in order to clearly illustrate the content of this application, several embodiments are provided to further explain the different implementations of this application. These embodiments are enumerated rather than exhaustive. Furthermore, for the sake of brevity, content mentioned in the preceding embodiments is often omitted in the following embodiments. Therefore, content not mentioned in the following embodiments can be referred to in the preceding embodiments.

[0026] Example 1

[0027] like Figure 1 The diagram shown is a flowchart illustrating a multi-band imaging method based on an ARM+DSP+FPGA heterogeneous platform provided in this embodiment. The method specifically includes the following steps:

[0028] S1. After the signal processor is powered on, it controls the FPGA to periodically compress the input sampling data into pulses to generate pulse pressure and stores the pulse pressure in the corresponding loop buffer space. When the FPGA receives the imaging start command, it sends an Srio interrupt carrying doorbell information to the ARM. The doorbell information is used to indicate the position of the pulse pressure in the loop buffer space of the current period.

[0029] It should be noted that one implementation of S1 can be:

[0030] An unused memory region on the chip is selected, divided into m parts. Each part stores the information required for DSP imaging in one band. The size of this memory region is determined based on the number of imaging bands m and the frame period N. Within one period, the FPGA is controlled to perform pulse compression processing on the input sampling data m times, where m is the number of imaging bands.

[0031] S2. When the ARM receives the SRIO interrupt, it determines the current pulse pressure band and location based on the doorbell information and triggers the DSP to start imaging.

[0032] It should be noted that one implementation of S2 can be:

[0033] S21. When the ARM receives the SRIO interrupt, it obtains the current doorbell information and determines whether the current pulse pressure is the pulse pressure of the first band based on the current doorbell information. Specifically, if the current doorbell information is greater than 0 and less than 2N-1, then the current pulse pressure is determined to be the pulse pressure of the first band.

[0034] S22. If the current pulse pressure is the pulse pressure of the first band, increment the counter by 1. When the value of the counter is greater than or equal to the frame period N, trigger the DSP to start imaging, clear the value of the counter to zero, and set the imaging start flag to 1.

[0035] S23: If the current pulse pressure is not the pulse pressure of the first band, determine whether the imaging start flag is 1;

[0036] If the value is 1, then increment the band count counter for the start of imaging in the current frame by 1;

[0037] If the band count counter for the start of imaging in the current frame is greater than or equal to m+1, then the imaging start flag is cleared, the band count counter for the start of imaging in the current frame is cleared, and the process returns to S21.

[0038] S3. When the DSP receives the start imaging command, it reads the pulse pressure in the circular buffer space, accumulates the pulse pressure of multiple bands, and completes multi-band imaging.

[0039] It should be noted that one implementation of S3 can be:

[0040] S31. When the DSP receives the start imaging command, it obtains the doorbell information of the last pulse compression of the current band accumulation frame, calculates relevant parameters to configure the imaging acceleration kernel, and sets the start imaging mode.

[0041] S32. Calculate the index of the current band accumulation frame in the circular buffer space based on the doorbell information of the last pulse compression of the current band accumulation frame;

[0042] S33. Based on the index of the current band accumulation frame in the circular buffer space, start the imaging acceleration kernel to perform imaging accumulation;

[0043] S34. Determine whether the current band's accumulated frames have been completed;

[0044] S35. If the accumulation is complete, set the imaging acceleration core to image upload mode and proceed to S36; otherwise, proceed to S33.

[0045] S36. Perform coherent accumulation of the current frame's imaging accumulation result with the previous frame;

[0046] S37. Determine whether imaging of multiple bands is complete. If imaging is complete, proceed to S31; otherwise, proceed to S32.

[0047] Furthermore, prior to S3, the following is also included:

[0048] The imaging time T1 for one band is set to be greater than 1 / f; the total imaging time T2 for multiple bands within one frame period is set to be less than N*1 / f; where f represents the repetition frequency.

[0049] In a more specific embodiment, the core design of the multi-band imaging method based on the ARM+DSP+FPGA heterogeneous platform includes the design of the imaging system, timing design, cyclic buffer address allocation design, ARM receiving pulse compression and controlling DSP imaging design, and DSP simultaneously generating multi-band images design.

[0050] 1. Imaging System Design

[0051] The timing sequence of the imaging system is as follows Figure 2 As shown, the entire system workflow is as follows:

[0052] After the signal processor powers on, the FPGA periodically compresses the input sampled data into pulses to generate pulse compression, and stores the current pulse compression in a pre-designed circular buffer. Within one pulse timer (PRT), the FPGA needs to perform m pulse compressions, where m is the number of imaging bands. When the FPGA receives the imaging start command, it sends an SRIO interrupt carrying doorbell information to the ARM, which indicates the position of the current PRT pulse compression in the circular buffer. After receiving the SRIO interrupt, the ARM determines whether the current pulse compression result is for the first band. If so, it starts counting. After counting to frame period N, it triggers the DSP to start imaging and resets the count value to zero. This process is repeated until the imaging ends.

[0053] Figure 2 Part ① describes the workflow of the powered-on ARM, and part ② describes the workflow of the powered-on DSP. The realization of simultaneous multi-band imaging relies on the timing relationship formed by the FPGA, ARM, and DSP.

[0054] 2. Timing Design

[0055] Please refer to Figure 3 , which is a schematic timing diagram during imaging accumulation. In this embodiment, the full-frame accumulation time of the first wavelength band is the process control point for the DSP to start imaging. After starting DSP imaging, the DSP sequentially performs imaging accumulation on pulse compression of m wavelength bands.

[0056] To ensure that the pulse compression of the second wavelength band satisfies the full-frame condition before the imaging accumulation of the second wavelength band, the following timing relationship shall be satisfied: the imaging time T1 of one wavelength band is greater than 1 / f; to ensure smooth progress of imaging in the next frame period, the following timing relationship shall be satisfied: the total imaging time T2 of m wavelength bands in one frame period is less than N*1 / f. (N is the frame period, and f is the pulse repetition frequency)

[0057] Therefore, in order to satisfy the normal operation of the entire imaging system, the timing relationships that need to be satisfied are:

[0058] ① T1>1 / f

[0059] ② T2<N*1 / f

[0060] Please refer to Figure 6 , the imaging time of one wavelength band is divided into three parts: the time for the imaging acceleration hard core to accumulate N pieces of pulse compression, the image upload time and the coherent accumulation time. Assuming that the time for the imaging acceleration hard core to accumulate one piece of pulse compression is t1 (this time is related to the frequency of the imaging acceleration hard core, the number of imaging pulse compression points, etc.), the image upload time of the imaging acceleration hard core is t2 (this time is related to the size of the imaging frame), and the coherent accumulation time is t3, then the imaging time T1 of one wavelength band is:

[0061] T1=N*t1+t2+t3

[0062] From the imaging timing ①, it can be obtained that:

[0063] T1>1 / f, that is, (N*t1+t2+t3)>1 / f. After derivation, it can be obtained that:

[0064] N>(1 / f-t3-t2) / t1

[0065] The total imaging time T2 of all wavelength bands is:

[0066] T2=m*(N*t1+t2+t3)

[0067] From the imaging timing ②, it can be obtained that:

[0068] T2<N*1 / f, that is, (m*(N*t1+t2+t3))<N*1 / f. After derivation, it can be obtained that:

[0069] N>f*m*(t2+t3) / (1-f*m*t1)

[0070] In summary, the frame period N needs to satisfy the following two conditions ③ and ④ simultaneously:

[0071] ③N>(1 / f-t3-t2) / t1

[0072] ④N>f*m*(t2+t3) / (1-f*m*t1)

[0073] Analyzing this formula, we can see that the frame period N is directly proportional to the number of imaging bands m and the repetition rate f. Therefore, when the required number of imaging bands m is larger or the repetition rate is higher, it can be achieved by increasing the frame period N.

[0074] 3. Circular cache address allocation design

[0075] Select an unused memory region on the chip, with the size Circular_buffer_Size as follows:

[0076] Circular_buffer_Size=2*N*m*Pulse_points

[0077] Please refer to the circular cache address design in this embodiment. Figure 4 The pulse compression base address for band A is PC_BaseAddr_waveA, and the pulse compression base address for band B is PC_BaseAddr_waveB. The m bands are arranged sequentially. Memory of size 2N*Pulse_points is allocated for each band. In each prt cycle, the FPGA generates the pulse compression and sends it to the corresponding address in the circular buffer, while also sending an SRIO interrupt with the corresponding doorbell information to the ARM.

[0078] This design sends the pulse compression result directly to the corresponding loop buffer address on the FPGA side, eliminating the need for the DSP to move the received pulse compression to the loop buffer address, thus increasing bandwidth.

[0079] Please refer to Figure 4 The one-to-one correspondence between the pulse compression result address Pulse_Addr and the doorbell information Bell_Info is as follows:

[0080] Band A:Pulse_Addr=PC_BaseAddr_waveA+Pulse_points*Bell_Info

[0081] Band B:Pulse_Addr=PC_BaseAddr_waveB+Pulse_points*(Bell_Info-2N)

[0082] Addresses of other bands are obtained by similar recursion. When the ARM receives an SRIO interrupt, it can determine which band the current pulse compression result belongs to according to the doorbell information, and obtain the address of the current pulse compression in the circular buffer.

[0083] 4. ARM receives pulse compression

[0084] An unused memory area on the chip is selected, which is divided into m parts, and each part is used to store information required for DSP imaging of each band. In the imaging system of the present invention, please refer to Figure 5 , the work undertaken by ARM receiving pulse compression is as follows:

[0085] Step 1: Wait for a pulse compression interrupt, obtain the doorbell information Bell_Info of the current interrupt, and determine whether the current pulse compression is the pulse compression of the first band according to the current doorbell information:

[0086] If the doorbell information satisfies 0 < Bell_Info < (2N-1), the current pulse compression is the pulse compression of the first band, and the process goes to step 2; if the doorbell information does not satisfy the above condition, the current pulse compression is the pulse compression of other bands, and the process goes to step 3;

[0087] Step 2: Increment the count prtcount_waveA by 1, when it is determined that prtcount_waveA ≥ N, record the current doorbell information Bell_Info as Bell_Info_wave_i, where i starts from band A, trigger the DSP to perform imaging, clear prtcount_waveA, and set the imaging start flag bit Sar_Startflag to 1; otherwise, go back to step 1.

[0088] Step 3: Determine whether Sar_Startflag is 1, if the flag is 1, increment the count wavecount by 1, where wavecount represents the number of bands at the start of current frame imaging. When it is determined that wavecount < (m+1), record the current doorbell information Bell_Info as Bell_Info_wave_i, where i starts from band B, and go to step 1; if the condition is not satisfied, clear wavecount, clear Sar_Startflag, and go to step 1; otherwise, go to step 1.

[0089] 5. DSP multi-band imaging algorithm

[0090] Please refer to Figure 6 , the multi-band imaging algorithm is divided into one-band imaging accumulation and m-band imaging, which respectively correspond to Figure 6 ① and ② in:

[0091] Step 1: Wait for the instruction to start imaging. If the instruction to start imaging is received, proceed to Step 2.

[0092] Step 2: Obtain the doorbell information Bell_Info_wave_i of the last pulse compression of the current band accumulation frame, calculate relevant parameters to configure the imaging acceleration box, and set the start imaging mode;

[0093] Step 3: Calculate the index of the current pulse pressure in the circular buffer:

[0094] Index=(Bell_Info_wave_i-2N*i-j+2N)&(2N-1)+2N*i

[0095] Where j is the current pulse compression position in the accumulation frame;

[0096] Step 4: Activate the imaging acceleration kernel to accumulate images;

[0097] Step 5: Determine whether the N pulse pressures have been accumulated. If they have been accumulated, set the imaging acceleration hard core to image upload mode and proceed to step 6; otherwise, proceed to step 3.

[0098] Step Six: Perform coherent accumulation of the current frame's imaging results with the previous frame. Determine whether imaging of m bands is complete. If imaging is complete, proceed to Step One; otherwise, proceed to Step Two.

[0099] This achieves multi-band imaging based on a heterogeneous ARM+DSP+FPGA platform.

[0100] In summary, this method achieves the following significant beneficial effects:

[0101] This method employs a DSP to implement the multi-band digital imaging portion, an ARM to implement pulse compression transmission, and an FPGA to pulse-compress the input sampled data. The pulse compression results are then cyclically stored in the corresponding DDR space, and an interrupt signal carrying doorbell information is sent to the ARM. This approach fully leverages the advantages of different processors, utilizing the powerful mathematical computation capabilities of the DSP, the parallel computing capabilities of the FPGA, and the transaction management capabilities of the ARM to significantly improve the real-time capability of simultaneously acquiring multiple images. Furthermore, this method provides the software with good scalability, maintainability, and reusability, allowing for flexible implementation of easily changeable components in software and increasing the system's optimization potential. In terms of implementation, by designing a reasonable timing sequence to complete multi-band imaging, rapid processing and real-time display are achieved, thus ensuring both real-time performance and processing quality of multi-band imaging.

[0102] Example 2

[0103] This embodiment provides a multi-band imaging system based on an ARM+DSP+FPGA heterogeneous platform. The system includes:

[0104] FPGA is used to control the signal processor to periodically compress the input sampling data into pulses after the signal processor is powered on, and to store the pulses in the corresponding loop buffer space. When the FPGA receives the imaging start command, it sends an ARM interrupt carrying doorbell information to the ARM. The doorbell information is used to indicate the position of the pulse in the loop buffer space of the current period.

[0105] The ARM is used to determine the current pulse pressure band and location based on the doorbell information when the ARM receives an SRI interrupt, and then trigger the DSP to start imaging.

[0106] The DSP is used to read the pulse compression in the circular buffer space after receiving the start imaging command, and to accumulate pulse compression in multiple bands to complete multi-band imaging.

[0107] In summary, this system has a clear architecture and well-defined division of labor. Leveraging the advantages of ARM in task control, it manages the multi-band imaging process. Data communication with the DSP is achieved through shared memory. The DSP and FPGA act as coprocessors, respectively handling imaging and pulse compression functions, making it a real-time, portable embedded system. This system is flexible, scalable, and versatile, exhibiting good real-time performance and versatility.

[0108] Example 3

[0109] In another feasible embodiment, this embodiment provides a multi-band imaging device based on an ARM+DSP+FPGA heterogeneous platform, the device specifically including:

[0110] A processor; and a memory for storing computer-executable instructions, which, when executed, cause the processor to perform the steps as described in any of the above method embodiments.

[0111] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A multi-band imaging method based on an ARM+DSP+FPGA heterogeneous platform, characterized in that, include: S1. After the signal processor is powered on, it controls the FPGA to periodically compress the input sampling data into pulses to generate pulse pressure and stores the pulse pressure in the corresponding loop buffer space. When the FPGA receives the imaging start command, it sends an Srio interrupt carrying doorbell information to the ARM. The doorbell information is used to indicate the position of the pulse pressure in the loop buffer space of the current period. S2. When the ARM receives the SRIO interrupt, it determines the current pulse pressure band and location based on the doorbell information and triggers the DSP to start imaging. S3. When the DSP receives the start imaging command, it reads the pulse compression in the circular buffer space, accumulates the pulse compression of multiple bands, and completes multi-band imaging. S2 includes: S21. When the ARM receives the SRIO interrupt, it obtains the current doorbell information and determines whether the current pulse pressure is the pulse pressure of the first band based on the current doorbell information. S22. If the current pulse pressure is the pulse pressure of the first band, increment the counter by 1. When the value of the counter is greater than or equal to the frame period N, trigger the DSP to start imaging, clear the value of the counter to zero, and set the imaging start flag to 1. S3 includes: S31. When the DSP receives the start imaging command, it obtains the doorbell information of the last pulse compression of the current band accumulation frame, calculates relevant parameters to configure the imaging acceleration kernel, and sets the start imaging mode. S32. Calculate the index of the current band accumulation frame in the circular buffer space based on the doorbell information of the last pulse compression of the current band accumulation frame; S33. Based on the index of the current band accumulation frame in the circular buffer space, start the imaging acceleration kernel to perform imaging accumulation; S34. Determine whether the current band's accumulated frames have been completed; S35. If the accumulation is complete, set the imaging acceleration core to image upload mode and proceed to S36; otherwise, proceed to S33. S36. Perform coherent accumulation of the current frame's imaging accumulation result with the previous frame; S37. Determine whether imaging of multiple bands is complete. If imaging is complete, proceed to S31; otherwise, proceed to S32.

2. The method according to claim 1, characterized in that, S1 includes: Within one cycle, the FPGA is controlled to perform pulse compression processing on the input sampling data m times, where m is the number of imaging bands.

3. The method according to claim 2, characterized in that, Before S1, it also includes: Select an unused memory area on the chip. This memory area is divided into m parts, each of which is used to store the information required for DSP imaging in one band. The size of this memory area is determined based on the number of imaging bands m and the frame period N.

4. The method according to claim 3, characterized in that, S21 includes: If the current doorbell information is greater than 0 and less than 2N-1, then the current pulse pressure is determined to be the pulse pressure of the first band, where N represents the frame period.

5. The method according to claim 4, characterized in that, Following S21, S23 is also included: If the current pulse pressure is not the pulse pressure of the first band, then determine whether the imaging start flag is 1; If the value is 1, then increment the band count counter for the start of imaging in the current frame by 1; If the band count counter for the start of imaging in the current frame is greater than or equal to m+1, then the imaging start flag is cleared, the band count counter for the start of imaging in the current frame is cleared, and the process returns to S21, where m is the number of imaging bands.

6. The method according to claim 1, characterized in that, Before S3, it also includes: Set the imaging time T1 for one band to be greater than 1 / f; Set the total imaging time T2 of multiple bands within one frame period to be less than N*1 / f; Where f represents the repetition frequency and N represents the frame period.

7. A multi-band imaging system based on an ARM+DSP+FPGA heterogeneous platform for performing the method of claim 1, characterized in that, include: FPGA is used to control the signal processor to periodically compress the input sampling data into pulses after the signal processor is powered on, and to store the pulses in the corresponding loop buffer space. When the FPGA receives the imaging start command, it sends an ARM interrupt carrying doorbell information to the ARM. The doorbell information is used to indicate the position of the pulse in the loop buffer space of the current period. The ARM is used to determine the current pulse pressure band and location based on the doorbell information when the ARM receives an SRI interrupt, and then trigger the DSP to start imaging. The DSP is used to read the pulse compression in the circular buffer space after receiving the start imaging command, and to accumulate pulse compression in multiple bands to complete multi-band imaging.

8. An electronic device, characterized in that, include: processor; And a memory arranged to store computer-executable instructions, which, when executed, cause the processor to perform the method as described in any one of claims 1 to 6.

Images