Holographic imaging system

Abstract

The present disclosure provides a holographic imaging system, comprising: a radio frequency transmitting device, an array antenna, a data processing device and a display device, wherein the radio frequency transmitting device generates a triggering electrical signal for triggering the array antenna to transmit an electromagnetic signal, and sends the triggering electrical signal to the array antenna; the array antenna determines the initial transmitting frequency of each array element in response to the triggering electrical signal; for each array element, the transmitting electromagnetic signal corresponding to each frequency is sequentially transmitted starting from the initial transmitting frequency in accordance with the specified frequency order of each frequency; and for each array element, the echo electromagnetic signal corresponding to the transmitting electromagnetic signal emitted by the array element and the specified adjacent array element corresponding to the array element is received, and the received echo electromagnetic signal is converted into a response electrical signal; the data processing device obtains the response electrical signal, performs imaging processing on the response electrical signal to obtain an imaging image; and the display device displays the imaging image.

Description

Technical Field

[0001] The present disclosure relates to the field of communication technology, and in particular, to a holographic imaging system. Background Art

[0002] Imaging detection technology is widely used in various application scenarios, especially active millimeter wave body security inspection devices. Active millimeter wave body security inspection devices use active millimeter wave imaging technology to effectively detect target objects (including metal objects and non-metal objects) hidden in various parts of the human body under clothing without directly contacting the body of the person to be tested, and can extract information such as the shape, size and location of the hidden target objects from the image generated based on the detection.

[0003] An active millimeter-wave body security inspection device generally includes a transceiver antenna array, which in turn includes a transmitting antenna array and a receiving antenna array, wherein the transmitting antenna array can transmit the millimeter-wave signal to free space (including air and vacuum) according to specific gain requirements and beam width requirements, and the receiving antenna array can receive the echo signal of the transmitted millimeter-wave signal after being reflected by the target object from the free space. Summary of the invention

[0004] In view of the above, the present disclosure provides a holographic imaging system. Through the holographic imaging system provided by the present disclosure, each array element in the array antenna uses a one-transmit-multiple-receive method to transmit and receive signals, which increases the equivalent phase center and thus increases the sampling points. From another perspective, the use of array elements is reduced while ensuring sufficient sampling points. In addition, under the multi-transmit and multi-receive transmission and reception mechanism of the array antenna, the frequencies emitted by each array element at each moment are different, which can shorten the acquisition time of data collected through echo electromagnetic signals, thereby improving the imaging efficiency of the holographic imaging system.

[0005] According to one aspect of the present disclosure, a holographic imaging system is provided, comprising: a radio frequency transmitting device, an array antenna, a data processing device and a display device, wherein the array antenna comprises array elements uniformly distributed in the order of rows and columns to form an antenna array; the array antenna is communicatively connected to the radio frequency transmitting device, and the data processing device is communicatively connected to the array antenna and the display device respectively; the radio frequency transmitting device is configured to: generate a triggering electrical signal for triggering the array antenna to transmit an electromagnetic signal, and send the triggering electrical signal to the array antenna; the array antenna is configured to: determine the initial transmitting frequency of each array element in response to the triggering electrical signal, wherein the operating frequency band of the holographic imaging system is divided into a plurality of frequencies, the number of the plurality of frequencies is not less than the number of the array elements, and each frequency is allocated to each array element as the initial transmitting frequency of each array element The invention relates to a method for transmitting electromagnetic signals of a plurality of array elements in a plurality of antennas, wherein the plurality of array elements have different initial transmitting frequencies; for each array element, transmitting electromagnetic signals corresponding to the plurality of frequencies in sequence starting from the initial transmitting frequency in accordance with the specified frequency order of the plurality of frequencies, wherein the frequencies of the transmitting electromagnetic signals transmitted by the plurality of array elements at each moment are different; and for each array element, receiving an echo electromagnetic signal corresponding to the transmitting electromagnetic signal emitted by the array element and a designated adjacent array element corresponding to the array element, and converting the received echo electromagnetic signal into a response electrical signal, wherein the designated adjacent array element is an array element adjacent to the array element in the antenna array and located at a designated position of the array element; the data processing device is configured to obtain the response electrical signal and perform imaging processing on the response electrical signal to obtain an imaging image; and the display device is configured to display the imaging image. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] A further understanding of the nature and advantages of the present disclosure may be achieved by referring to the following drawings.In the accompanying drawings, similar components or features may have the same reference numeral.

[0007] Figure 1 A block diagram of an example of a holographic imaging system according to the present disclosure is shown.

[0008] Figure 2 A schematic diagram showing an example of uniform distribution of array elements in an array antenna according to the present disclosure.

[0009] Figure 3 A schematic diagram showing an example of an array antenna including sub-arrays according to the present disclosure is shown.

[0010] Figure 4 A schematic diagram showing an example of an equivalent phase center of an array antenna according to the present disclosure.

[0011] Figure 5A block diagram of another example of a holographic imaging system according to the present disclosure is shown.

[0012] Figure 6 A block diagram of another example of a holographic imaging system according to the present disclosure is shown.

[0013] Figure 7 A block diagram of another example of a holographic imaging system according to the present disclosure is shown. DETAILED DESCRIPTION

[0014] The subject matter described herein will be discussed below with reference to example implementations. It should be understood that the discussion of these implementations is only to enable those skilled in the art to better understand and implement the subject matter described herein, and is not a limitation of the scope of protection, applicability or examples set forth in the claims. The functions and arrangements of the elements discussed may be changed without departing from the scope of protection of the present disclosure. Various examples may omit, replace or add various processes or components as needed. In addition, the features described relative to some examples may also be combined in other examples.

[0015] As used herein, the term "including" and its variations represent open terms, meaning "including but not limited to". The term "based on" means "based at least in part on". The terms "one embodiment" and "an embodiment" mean "at least one embodiment". The term "another embodiment" means "at least one other embodiment". The terms "first", "second", etc. may refer to different or the same objects. Other definitions may be included below, whether explicit or implicit. Unless the context clearly indicates otherwise, the definition of a term is consistent throughout the specification.

[0016] Imaging detection technology is widely used in various application scenarios, especially active millimeter wave body security inspection devices. Active millimeter wave body security inspection devices use active millimeter wave imaging technology to effectively detect target objects (including metal objects and non-metal objects) hidden in various parts of the human body under clothing without directly contacting the body of the person to be tested, and can extract information such as the shape, size and location of the hidden target objects from the image generated based on the detection.

[0017] An active millimeter-wave body security inspection device generally includes a transceiver antenna array, which in turn includes a transmitting antenna array and a receiving antenna array, wherein the transmitting antenna array can transmit the millimeter-wave signal to free space (including air and vacuum) according to specific gain requirements and beam width requirements, and the receiving antenna array can receive the echo signal of the transmitted millimeter-wave signal after being reflected by the target object from the free space.

[0018] However, the array antennas currently used in security inspection devices use a mechanical scanning transceiver mechanism. After each transmission, the array antenna needs to move to the next designated position, resulting in a long data collection time.

[0019] In view of the above, the present disclosure provides a holographic imaging system, including: a radio frequency transmitting device, an array antenna, a data processing device and a display device, wherein each array element included in the array antenna is evenly distributed in the order of rows and columns to form an antenna array; the array antenna is communicatively connected to the radio frequency transmitting device, and the data processing device is communicatively connected to the array antenna and the display device respectively; the radio frequency transmitting device is configured to: generate a trigger electrical signal for triggering the array antenna to transmit a signal, and send the trigger electrical signal to the array antenna; the array antenna is configured to: determine the initial transmission frequency of each array element in response to the trigger electrical signal; for each array element, in accordance with the specified frequency order of each frequency, sequentially transmit the transmission electromagnetic signal corresponding to each frequency starting from the initial transmission frequency; and for each array element, receive the echo electromagnetic signal corresponding to the transmission electromagnetic signal emitted by the array element and the specified adjacent array element corresponding to the array element, and convert the received echo electromagnetic signal into a response electrical signal; the data processing device is configured to: obtain the response electrical signal, perform imaging processing on the response electrical signal to obtain an imaging image; the display device is configured to: display the imaging image. Through the holographic imaging system provided by the present disclosure, each array element in the array antenna uses a one-transmit-multiple-receive method to transmit and receive signals, which increases the equivalent phase center and reduces the use of array elements while ensuring that the number of received echo electromagnetic signals remains unchanged or even increases. In addition, under the multi-transmit and multi-receive transmission and reception mechanism of the array antenna, the frequencies emitted by each array element at each moment are different, which can shorten the acquisition time of data collected through echo electromagnetic signals, thereby improving the imaging efficiency of the holographic imaging system.

[0020] The holographic imaging system provided by the present invention is described in detail below with reference to the accompanying drawings.

[0021] Figure 1 A block diagram of an example of a holographic imaging system 100 according to the present disclosure is shown. In one example, the holographic imaging system 100 of the present disclosure can be applied to security inspection equipment. Of course, the holographic imaging system 100 can also be applied to equipment in other application scenarios.

[0022] like Figure 1 As shown, the holographic imaging system 100 includes a radio frequency transmitting device 110, an array antenna 120, a data processing device 130, and a display device 140. The array antenna 120 can be connected to the radio frequency transmitting device 110 for communication, and the data processing device 130 can be connected to the array antenna 120 and the display device 140 for communication, respectively, and the communication connection mode can include wired connection and wireless connection.

[0023] In the holographic imaging system 100, the RF transmitting device 110 can generate a trigger electrical signal, and the trigger electrical signal is used to trigger the array antenna to transmit an electromagnetic signal. In one example, the RF transmitting device 110 includes a processor, which can be used to generate a trigger electrical signal and set a generation rule of the trigger electrical signal. The generation rule of the trigger electrical signal includes a generation time, a generation time interval, etc. In another example, the RF transmitting device 110 can be controlled by other devices in the holographic imaging system 100 to generate a trigger electrical signal. For example, other devices send a trigger pulse to the RF transmitting device 110, and the RF transmitting device 110 generates a trigger electrical signal in response to the trigger pulse.

[0024] The trigger electrical signal generated by the RF transmitting device 110 includes multiple electrical signals corresponding to multiple frequencies divided by the working frequency band, each frequency corresponds to a trigger electrical signal, and the trigger electrical signals corresponding to different frequencies are used to trigger different array elements in the array antenna. The RF transmitting device 110 can also send the generated trigger electrical signal to the array antenna to trigger the array antenna to transmit an electromagnetic signal.

[0025] In the present disclosure, the array antenna includes a plurality of array elements, each of which can emit a transmitted electromagnetic signal and can also receive an echo electromagnetic signal corresponding to the transmitted electromagnetic signal. In one example, the array antenna in the present disclosure can be arranged into a linear array or a planar array, and each array element in the linear array or the planar array is located in the same plane. The following is an explanation using a planar array as an example.

[0026] In the present disclosure, the array elements included in the array antenna can be evenly distributed in the order of rows and columns to form an antenna array, and the antenna array can be rectangular or square. In the antenna array, the spacing distances between adjacent array elements in the row direction are equal, and the spacing distances between adjacent array elements in the column direction are equal. In one example, the spacing distances between adjacent array elements in the row and column directions are equal. In another example, the spacing distances between adjacent array elements in the row direction may be different from the spacing distances between adjacent array elements in the column direction.

[0027] In a division method for array antennas, in an area for arranging array antennas, the height H and width L of the area are determined, and a uniform division method of the height and width is determined according to the number of array elements to be arranged. In one example, the distribution method of the array antenna can be determined as follows: M array elements are arranged in each column (in the height H direction), N array elements are arranged in each row (in the width L direction), and the total number of arranged array elements M×N is the number of array elements to be arranged, where M and N are positive integers. The height h of the array element square corresponding to each array element is H / M, and the width l of the array element square corresponding to each array element is L / N. Each array element square is used to arrange one array element, and each array element can be arranged at the center of the corresponding array element square. Figure 2 For example, Figure 2 A schematic diagram showing an example of uniform distribution of array elements in an array antenna according to the present disclosure.

[0028] In one example, the spacing distance between two adjacent array elements can be equivalent to the height h and width l of the array element grid, so that the height h can be set to be less than or equal to 2h0 and the width l can be set to be less than or equal to 2l0. h0 and l0 represent the sampling interval in height and width, respectively. For example, h0 can be 5 mm and l0 can also be 5 mm. When the height h is less than or equal to 2h0 and the width l is less than or equal to 2l0, it can be ensured that the sampling frequency is greater than twice the highest frequency in the signal, thereby ensuring the integrity of the sampling information.

[0029] In one arrangement of the array antenna, the array antenna may be arranged to include a plurality of subarrays, each subarray being evenly distributed in the order of rows and columns, each subarray may include a plurality of array elements, and all array elements in each subarray may be evenly distributed in the order of rows and columns.

[0030] Figure 3 FIG. 2 is a schematic diagram showing an example of an array antenna 200 including sub-arrays according to the present disclosure. Figure 3 As shown, the array antenna 200 is divided into a plurality of evenly arranged sub-arrays, each black frame indicates a sub-array, and the number of array elements and the arrangement of the array elements in each sub-array are the same.

[0031] In this arrangement, the sub-arrays may be evenly divided in the area for arranging the array antenna. In one example, the number of sub-arrays may be determined to be M. A ×N A , where M A Indicates the number of sub-matrices in each column (in the height H direction), N A represents the number of sub-arrays arranged in each row (in the width L direction), then the height H' of each sub-array is H / M A , the width L′ of each subarray is L / NA .

[0032] Furthermore, for each sub-array, the array element grid is evenly divided for arranging the array elements. In one example, the number of array elements arranged in each sub-array is M. S ×N S , where M S Indicates the number of array elements in each column (in the height H direction), N S represents the number of array elements arranged in each row (in the width L direction). Then in each sub-array, the height h of the array element grid corresponding to each array element is H′ / M S , the width l of the array element grid corresponding to each array element is L′ / N S In this way, the total number of array elements arranged is: M A ×N A ×M S ×N S .

[0033] In the present disclosure, the working frequency band of the holographic imaging system can be divided into multiple frequencies. Therefore, the working frequency band can be uniformly divided in advance to obtain multiple frequencies. The frequency difference Δf between adjacent frequencies in each of the obtained frequencies is the same.

[0034] In one division method, the working frequency band can be evenly divided according to the maximum frequency and the minimum frequency of the working frequency band and the number of frequencies to be divided. In this division method, the formula Calculate the frequency difference Δf between adjacent frequencies, where f max Indicates the maximum frequency in the operating frequency band, f min Indicates the minimum frequency in the working frequency range, Num f represents the number of frequencies to be divided. Then, the individual frequencies can be obtained as: f i =f min +iΔf, where i is greater than 0 and less than or equal to Num f In the obtained frequencies, in ascending order, the first frequency is the minimum frequency f min , the second frequency is f min +Δf, and so on, until the maximum frequency f max .

[0035] In the present disclosure, the number of the obtained multiple frequencies is not less than the number of array elements, so that a different initial transmission frequency can be allocated to each array element. In addition, the frequencies of the transmission signals sent by each array element at each moment can also be different. In an example, the number of the obtained multiple frequencies is the same as the number of array elements. In this example, the working frequency band can be evenly divided according to the number of array elements to obtain the number of frequencies.

[0036] In the present disclosure, after obtaining each frequency, the array antenna can determine the initial transmission frequency of each array element in response to the trigger electrical signal. In the array antenna, each frequency can be allocated to each array element as the initial transmission frequency of each array element.

[0037] In the present disclosure, the frequencies allocated to each array element are different, so that the initial transmission frequency of each array element is different. In a frequency allocation method, when the number of obtained frequencies is greater than the number of array elements, part of the obtained frequencies can be allocated to each array element, and the number of the partial frequencies is the same as the number of array elements. The partial frequencies can be selected according to a specified order of frequencies, and the specified order includes an order from small to large, an order from large to small, and other orders. In another frequency allocation method, when the number of obtained frequencies is equal to the number of array elements, all frequencies can be allocated to each array element.

[0038] In the present disclosure, each array element is evenly distributed in the order of rows and columns, so that the order of each array element can be determined according to the specified order. For example, the specified order includes the order from left to right and from top to bottom. The obtained frequencies can be sequentially assigned to each array element arranged according to the specified order in the specified order. For example, the number of frequencies is equal to the number of array elements, the specified order of frequencies is from small to large, and the specified order of array elements is from left to right and from top to bottom. Then, the minimum frequency can be assigned to the array element in the first row and the first column, and the second frequency in the specified order can be assigned to the array element in the first row and the second column, and so on, until the maximum frequency is assigned to the array element in the last row and the last column.

[0039] In one example, when the array antenna is arranged to include multiple sub-arrays, each array element can be represented as Indicates the i A Row j A The array element in the i-th row and j-th column of the sub-matrix of the column. The initial transmission frequency It can be expressed as: f1+[(i-1)M S +(j-1)N S ]Δf+(i A -1)j A M S NS Δf. Where, M S N represents the number of array elements in each column (in the height H direction) in each sub-array. S represents the number of array elements arranged in each row (in the width L direction) in each sub-array.

[0040] In one example, when the array antenna does not include a subarray, each array element may be represented as A ij , represents the array element in the i-th row and j-th column. For array element A ij The initial transmission frequency f ij It can be expressed as: f1+[(i-1)j+(j-1)]Δf.

[0041] In the array antenna, for each array element, a transmission electromagnetic signal corresponding to each frequency is transmitted in sequence starting from the initial transmission frequency according to the specified frequency order of each frequency.

[0042] In the present disclosure, each array element is triggered to emit a transmitting electromagnetic signal of an initial transmitting frequency at the same time, and the intervals between each array element emitting the transmitting electromagnetic signal are the same, so that each array element is synchronized with other array elements when emitting each transmitting electromagnetic signal. At each moment, each array element can emit a transmitting electromagnetic signal at the same time, and the frequencies of the transmitting electromagnetic signals emitted by each array element at each moment are different.

[0043] In the present disclosure, the specified frequency order of each frequency can be customized. By specifying the frequency order, all array elements transmit electromagnetic signals according to the specified frequency order, and the frequencies of the initial electromagnetic signals transmitted by each array element are different, thereby ensuring that the frequencies of the electromagnetic signals transmitted by each array element at each moment are different.

[0044] In one example, the specified frequency order includes an order in which the frequencies increase in sequence or an order in which the frequencies decrease in sequence. If the initial transmission frequencies of the array elements are different, the initial transmission frequencies of the array elements correspond to different starting positions in the specified frequency order. In one example, the specified frequency order includes an order in which the frequencies increase in sequence in a closed loop or an order in which the frequencies decrease in sequence. In the closed-loop specified frequency order, the next order of the end position is the starting position, and a closed-loop order is formed based on this. For example, when the specified frequency order is an order in which the frequencies increase in sequence in a closed loop, the next order of the maximum frequency is the minimum frequency. It should be noted that in addition to the order in which the frequencies increase in sequence or the order in which the frequencies decrease in sequence, the specified frequency order may also be other frequency orders.

[0045] In one example, for each array element, the transmit electromagnetic signals corresponding to each frequency are transmitted in sequence starting from the initial transmit frequency according to the specified frequency order of each frequency, until the transmit electromagnetic signals corresponding to all frequencies are transmitted once.

[0046] For example, the frequency order of each frequency is a closed loop from the minimum frequency f min To the maximum frequency f max In increasing order, the initial transmission frequency of an array element is f d , then the array element emits f d After transmitting electromagnetic signal, it will send out f d+1 The electromagnetic signal emitted by the array element is f. max After the electromagnetic signal is emitted, it will continue to emit f min The electromagnetic signal is emitted until f d-1 After the electromagnetic signal is transmitted, the array element ends the transmission. d-1 、f d and f d+1 Both are greater than the minimum frequency and less than the maximum frequency.

[0047] In another example, the frequency corresponding to the transmitted electromagnetic signal emitted by each array element may include only some of the obtained multiple frequencies. In another example, the transmitted electromagnetic signals corresponding to all the obtained frequencies are transmitted once as one round of signal transmission, and each array element may perform one or more rounds of signal transmission.

[0048] In the present disclosure, each transmitted electromagnetic signal can be represented as: Among them, f a represents the frequency corresponding to the transmitted electromagnetic signal, t represents the propagation time of the signal, which includes the time required for the signal to be transmitted from the array element to be received by the array element, and k represents the pulse frequency modulation slope. k is calculated according to the formula It is obtained that, where B represents the bandwidth of the working frequency band, and T represents the signal transmission period.

[0049] In the present disclosure, the transmitting electromagnetic signal emitted by each array element is reflected after reaching the target area point to form an echo electromagnetic signal, and the echo electromagnetic signal is propagated to reach the receiving array element in the array antenna, and the receiving array element can be the array element that emits the transmitting electromagnetic signal, or it can be other array elements. The target area point can be any point on the detected target located in the target area. For example, in the button area of ​​the security inspection equipment, the detected target is a person, and the target area point for reflecting the transmitting electromagnetic signal can be any point on the person.

[0050] In the array antenna, for each array element, an echo electromagnetic signal corresponding to the transmitted electromagnetic signal emitted by the array element and the designated adjacent array element corresponding to the array element is received.

[0051] The array antenna in the present disclosure includes each array element that adopts a one-transmit-multiple-receive transceiver mechanism, and the echo electromagnetic signal corresponding to each transmitted electromagnetic signal emitted by each array element can be received by multiple array elements. Accordingly, in addition to receiving the echo electromagnetic signal corresponding to the transmitted electromagnetic signal emitted by itself, each array element can also receive the echo electromagnetic signal corresponding to the transmitted electromagnetic signal emitted by other array elements.

[0052] In the present disclosure, the designated adjacent array element may be an array element that is adjacent to the array element in the antenna array and is located at a designated position of the array element. The designated position is based on the antenna array. Figure 3 For example, in Figure 3 In the antenna array shown, the array element in the first row and second column is located above the array element in the second row and second column, the array element in the second row and first column is located to the left of the array element in the second row and second column, and the array element in the first row and first column is located above and to the left of the array element in the second row and second column.

[0053] In the present disclosure, a transceiver channel can be formed between an array element that sends a transmission signal and an array element that receives a corresponding echo signal, and each transceiver channel can be regarded as an equivalent phase center. When the array element that sends a transmission signal and the array element that receives a corresponding echo signal are the same array element, the array element can also be regarded as an equivalent phase center. In addition, the array element that sends a transmission signal and each designated adjacent array element corresponding to the array element can also form an equivalent phase center, and the formed equivalent phase center is located at a position other than the position of each array element, for example, at a position between two array elements, which is equivalent to adding an equivalent phase center on the basis of the original array element distribution. Based on the fact that each equivalent phase center can be considered to be equivalent to a sampling point, these newly added equivalent phase centers can be considered to be newly added sampling points.

[0054] Figure 4 A schematic diagram showing an example of an equivalent phase center of an array antenna according to the present disclosure. Figure 4 As shown, the array elements in the array antenna are evenly distributed in the order of rows and columns, and each array element can be regarded as an equivalent phase center. In addition, the transceiver channel formed between two adjacent array elements can be equivalent to an equivalent phase center. For example, the array element in the first row and the first column and the array element in the first row and the second column can form a transceiver channel, and the transceiver channel can be equivalent to an equivalent phase center, which is the equivalent phase center represented by the black dot between the two array elements.

[0055] By considering the transceiver channel formed by each array element and the designated adjacent array element as an equivalent phase center, it is equivalent to adding a new sampling point on the basis of the original array element distribution. Through this equivalent phase method, the equivalent phase center can be added on the basis of the original array element distribution, which is equivalent to adding a sampling point. From another perspective, replacing the array element with the equivalent phase center of the transceiver channel formed by two array elements can reduce the number of array elements used.

[0056] In one example, when the array antenna does not include a sub-array, each array element located at the edge of the antenna array may correspond to a designated adjacent array element, and the number of designated adjacent array elements may be different. Figure 2 For example, the designated adjacent array element is the array element that is adjacent to the array element in the antenna array and is located above, to the right, and above the right of the array element. Then, the array element in the first row and first column at the edge of the antenna array has one designated adjacent array element corresponding to it, and the array element in the fifth row and first column has three designated adjacent array elements corresponding to it. In another example, the array element at the edge of the antenna array may have no corresponding designated adjacent array element. Figure 2 For example, the designated adjacent array element is an array element adjacent to the array element in the antenna array and located above, to the right, and to the upper right of the array element. The array element located in the first row and the fifth column has 0 designated adjacent array elements.

[0057] In one example, when the array antenna is arranged to include multiple sub-arrays, the sub-arrays are independent of each other when transmitting and receiving signals, and a transmitting and receiving channel is formed only by array elements in the same sub-array, and no transmitting and receiving channel is formed between two array elements in different sub-arrays.

[0058] In this example, the designated adjacent array element of each array element is an array element that is adjacent to the array element in the subarray to which the array element belongs and is located at the designated position of the array element. Figure 3 For example, the first sub-array includes array elements in the first row and first column, the first row and second column, the second row and first column, and the second row and second column. For this sub-array, only the four array elements themselves and each other can form a transceiver channel, and the four array elements will not form a transceiver channel with array elements in other sub-arrays.

[0059] For each sub-array, each array element located at the edge of the sub-array may correspond to a designated adjacent array element, and the number of designated adjacent array elements may be different. Figure 3 For example, the designated adjacent array elements of each array element are the array elements that are adjacent to the array element in the sub-array to which the array element belongs and are located above, to the right, and above the right of the array element. Then, the array element in the first row and first column at the edge of the first sub-array has one corresponding designated adjacent array element, and the array element in the second row and first column has three corresponding designated adjacent array elements. In addition, the array element at the edge of the sub-array may have no corresponding designated adjacent array element. Figure 3For example, the designated adjacent array elements of each array element are the array elements that are adjacent to the array element in the sub-array to which the array element belongs and are located above, to the right, and to the upper right of the array element. The array element located in the first row and second column has 0 designated adjacent array elements.

[0060] In one example, the designated orientation may include above, right side and upper right side, then the designated adjacent array element of each array element is an array element adjacent to the array element and located above, right side and upper right side of the array element, so that the number of designated adjacent array elements of each array element is at most 3. When an array element sends out a transmitted electromagnetic signal, the echo electromagnetic signal corresponding to the transmitted electromagnetic signal can be received by the array element itself and also by the designated adjacent array elements located above, right side and upper right side of the array element. When there are only less than 3 designated adjacent array elements, it is received by the designated adjacent array elements.

[0061] by Figure 4 For example, the designated adjacent array elements corresponding to the array element in the second row and first column include the array element in the first row and first column above the array element, the array element in the second row and second column on the right, and the array element in the first row and second column on the upper right. Then, the echo electromagnetic signal corresponding to the transmitted electromagnetic signal emitted by the array element can be received by the array element itself, the array element in the first row and first column, the array element in the second row and second column on the right, and the array element in the first row and second column on the upper right.

[0062] by Figure 4 For example, Figure 4 The array shown can be a subarray or a complete antenna array. Figure 4 As shown, the array includes 5×5 array elements, and the equivalent phase centers formed between different array elements are distributed between each two adjacent array elements, and the equivalent phase centers are distributed at the positions between all two adjacent array elements.

[0063] In this example, when the antenna array includes sub-arrays, for each sub-array, the position of the lower left corner of the sub-array can be used as the origin, the horizontal direction as the x-axis, and the vertical direction as the y-axis, such as Figure 4 As shown. The transceiver channel corresponding to each transmitted electromagnetic signal can be expressed as follows:

[0064]

[0065] The arrow → indicates the direction of signal propagation, the left side of the arrow → indicates the array element that sends out the transmitted electromagnetic signal, and the right side indicates the array element that receives the corresponding echo electromagnetic signal. The array element that receives the corresponding echo electromagnetic signal is

[0066] Since there are less than three designated adjacent array elements corresponding to the array elements at the edge of the subarray, an on-off function is added to the above formula to limit the on-off state of each transceiver channel, so that the transceiver channel corresponding to each transmitted electromagnetic signal can be expressed as follows:

[0067]

[0068] Among them, (.*) indicates the multiplication of the elements at the corresponding positions of the left and right matrices, that is, dot product. Tag12, Tag21 and Tag22 indicate the on / off status of the corresponding transceiver channels, and their values ​​can be 0 or 1. 0 indicates that the transceiver channel is disconnected, that is, there is no transceiver channel, and 1 indicates that the transceiver channel is connected.

[0069] in, as well as Among them, i and j represent the position of the array element that transmits the electromagnetic signal in the subarray, M s Indicates the total number of rows in the subarray, N s Indicates the total number of columns in the subarray.

[0070] In another example, the designated orientation may include above, left, and upper left, and the designated adjacent array element of each array element is an array element adjacent to the array element and located above, on the left, and on the upper left of the array element, so that the number of designated adjacent array elements of each array element is at most 3. When an array element sends out a transmitted electromagnetic signal, the echo electromagnetic signal corresponding to the transmitted electromagnetic signal can be received by the array element itself and also by the designated adjacent array elements located above, on the left, and on the upper left of the array element. When there are only less than 3 designated adjacent array elements, it is received by the designated adjacent array elements.

[0071] by Figure 4 For example, when the designated adjacent array elements of the array element in the second row and second column include the array element in the first row and first column, the array element in the first row and second column, and the array element in the second row and first column, when the array element sends out a transmitted electromagnetic signal, the array element in the first row and first column, the array element in the first row and second column, and the array element in the second row and first column can all receive the echo electromagnetic signal corresponding to the transmitted electromagnetic signal.

[0072] In another example, the designated orientation may include below, left side and lower left side, then the designated adjacent array element of each array element is an array element adjacent to the array element and located below, to the left and to the lower left side of the array element, so that the number of designated adjacent array elements of each array element is at most 3. When an array element sends out a transmitted electromagnetic signal, the echo electromagnetic signal corresponding to the transmitted electromagnetic signal can be received by the array element itself and also by the designated adjacent array elements located below, to the left and to the lower left side of the array element. When there are only less than 3 designated adjacent array elements, it is received by the designated adjacent array elements.

[0073] by Figure 4 For example, when the designated adjacent array elements of the array element in the first row and second column include the array element in the first row and first column, the array element in the second row and first column, and the array element in the second row and second column, when the array element sends out a transmitted electromagnetic signal, the array element in the first row and first column, the array element in the second row and first column, and the array element in the second row and second column can all receive the echo electromagnetic signal corresponding to the transmitted electromagnetic signal.

[0074] In another example, the designated orientation may include below, right side and lower right side, then the designated adjacent array element of each array element is an array element adjacent to the array element and located below, to the right side and lower right side of the array element, so that the number of designated adjacent array elements of each array element is at most 3. When an array element sends out a transmitted electromagnetic signal, the echo electromagnetic signal corresponding to the transmitted electromagnetic signal can be received by the array element itself and also by the designated adjacent array elements located below, to the right side and lower right side of the array element. When there are only less than 3 designated adjacent array elements, it is received by the designated adjacent array elements.

[0075] by Figure 4 For example, when the designated adjacent array elements of the array element in the first row and first column include the array element in the first row and second column, the array element in the second row and first column, and the array element in the second row and second column, when the array element sends out a transmitted electromagnetic signal, the array element in the first row and second column, the array element in the second row and first column, and the array element in the second row and second column can all receive the echo electromagnetic signal corresponding to the transmitted electromagnetic signal.

[0076] In the above four examples, through the above four settings for the specified orientation, the transceiver channel formed between two different array elements can be regarded as an equivalent phase center, and the equivalent phase center is located between the two array elements. Therefore, in the antenna array, an equivalent phase center will be added between all adjacent array elements, and each equivalent phase center is equivalent to a sampling point, thereby increasing the number of sampling points. In addition, the equivalent phase centers formed by this setting method for the specified orientation will not overlap, avoiding repeated information collection of overlapping equivalent phase centers, thereby improving the efficiency of array antenna information collection.

[0077] In the present disclosure, the receiving array element of each echo electromagnetic signal is determined, and the transmitting array element that sends the transmitting electromagnetic signal corresponding to the echo electromagnetic signal is also determined, so that the signal propagation time τ can be calculated according to the spatial positions of the receiving array element and the transmitting array element constituting the transceiver channel and the target position of the reflected signal. b , then each echo electromagnetic signal can be expressed as: Among them, f brepresents the frequency of the echo electromagnetic signal, k represents the pulse frequency modulation slope, and δ(x, y, z) represents the electromagnetic scattering intensity at the target position. The electromagnetic scattering intensity of different objects is different.

[0078] For each array element, after a signal transmission, one or more echo electromagnetic signals can be received, for example, four echo electromagnetic signals can be received. Then the echo electromagnetic signal received by each array element can be expressed as That means the i A Row j A The echo electromagnetic signal received by the array element in the i-th row and j-th column of the sub-array of the column. Correspondingly, the echo electromagnetic signal received by each sub-array

[0079]

[0080] Furthermore, the echo electromagnetic signal R received by the antenna array can be expressed as:

[0081]

[0082] in, Indicates the i A Row j A The echo electromagnetic signal received by the sub-array of the column.

[0083] In the present disclosure, after receiving the echo electromagnetic signal, the array antenna can also convert the received echo electromagnetic signal into a corresponding response electrical signal. The echo electromagnetic signal corresponds to the response electrical signal obtained by conversion, and the frequency corresponding to the response electrical signal is the frequency of the corresponding echo electromagnetic signal.

[0084] In the present disclosure, the data processing device 130 may obtain the response electrical signal. In one example, the data processing device 130 may directly obtain the response electrical signal from the array antenna 120 .

[0085] The data processing device 130 may also perform imaging processing on the response electrical signal to obtain an imaging image. In one example, the data processing device 130 may use a SAR (Synthetic Aperture Radar) imaging algorithm to perform imaging processing, and the obtained imaging image may be a scattering image.

[0086] The data processing device 130 may send the obtained imaging image to the display device 140 so as to display the imaging image on the display device 140. In one example, the holographic imaging system 100 may further include a data storage device, the data processing device 130 may store the imaging image and other data in the data storage device, and the display device 140 may obtain the imaging image data from the data storage device to display the imaging image.

[0087] The data processing device 130 can also analyze and detect the image to detect whether there are contraband in the target object. If there are contraband, an alarm message can be issued, and the alarm message and the image can be sent to the display device 140.

[0088] In an example, the data processing device 130 may reorder the acquired response electrical signals in order of frequency in array elements to obtain reordered response electrical signals.

[0089] In this example, each array element can receive a response electrical signal corresponding to each frequency. For each array element, the response electrical signals corresponding to each frequency can be reordered in order of frequency, either from small to large or from large to small.

[0090] After obtaining the reordered response electrical signals, the data processing device 130 may perform imaging processing on the reordered response electrical signals to obtain an imaging image.

[0091] In one example, the data processing device 130 may also perform blurring processing on the private part of the target object in the image to protect the privacy of the target object.

[0092] In one example, the holographic imaging system 100 may further include a power supply device, which may supply power to various devices in the holographic imaging system 100 .

[0093] Figure 5 A block diagram of another example of a holographic imaging system 100 according to the present disclosure is shown.

[0094] like Figure 5 As shown, the holographic imaging system 100 may further include a radio frequency receiving device 150 , which may be communicatively connected to the radio frequency transmitting device 110 , the array antenna 120 , and the data processing device 130 .

[0095] In an example, the RF receiving device 150 may obtain a response electrical signal from the array antenna 120 , and then may send the response electrical signal to the data processing device 130 .

[0096] In another example, after the RF receiving device 150 obtains the response electrical signal from the array antenna 120, it can perform specified data processing on the obtained response electrical signal and send the processed response electrical signal to the data processing device 130. The specified data processing may include at least one of amplification processing, mixing processing, and filtering processing.

[0097] In one example, the RF transmitting device 110 may send the frequencies corresponding to the trigger electrical signals sent to the array antenna 120 to the RF receiving device 150. The RF receiving device 150 may amplify, mix, filter, etc. the acquired response electrical signals according to the frequencies corresponding to the trigger electrical signals.

[0098] Figure 6 A block diagram of another example of a holographic imaging system 100 according to the present disclosure is shown.

[0099] like Figure 6 As shown, the holographic imaging system 100 may further include a data acquisition device 160 , which may be communicatively connected to the data processing device 130 .

[0100] In this example, the data acquisition device 160 may include at least one sensor selected from the group consisting of a camera, a temperature sensor, a metal detector, etc. Through these sensors, the data acquisition device 160 may acquire corresponding data.

[0101] The temperature sensor can provide temperature measurement data, which can be used to correct the data to be imaged so as to improve the accuracy of the imaging data.

[0102] The metal detector can provide metal detection data, and the metal detection data can be combined with the detection results of the foreign object detection processing performed by the holographic imaging system to obtain the foreign object detection results of the holographic imaging system.

[0103] The camera device can capture an image of a target object, which is an object detected by the holographic imaging system. When the target object is a person, the camera device can capture the image of the person to perform face recognition, movement recognition, etc. based on the image of the person.

[0104] In one example, multiple camera devices can be set up to form a three-dimensional point cloud measurement device, which can provide three-dimensional point cloud data of the target object. The holographic imaging system can fuse and display the three-dimensional point cloud data, three-dimensional image data and foreign body detection results to accurately determine the location of the detected foreign body.

[0105] In a 3D point cloud measurement device, multiple cameras can shoot the target object from multiple angles. The 3D point cloud measurement device uses optical camera measurement technology to perform real-scene 3D modeling of the measured object. In order to avoid the blind spot of the camera, the angular difference between the images collected by two adjacent cameras can be kept smaller than the first angle, for example, 15°, and the overlapping angle can be greater than the second angle, for example, 60°.

[0106] In an example of the present disclosure, the holographic imaging system 100 may further include a central control device 170 , which may be communicatively connected to the radio frequency transmitting device 110 , the data processing device 130 , and the display device 140 , respectively.

[0107] In this example, the central control device 170 can control the RF transmitting device 110 by outputting a trigger pulse, so as to control the RF transmitting device 110 to generate trigger electrical signals of different frequencies. In addition, the central control device 170 can also control the data processing device 130 and the display device 140.

[0108] In an example, when the holographic imaging system 100 may further include a radio frequency receiving device 150 , the central control device 170 may further be communicatively connected with the radio frequency receiving device 150 to control the radio frequency receiving device 150 .

[0109] In another example, when the holographic imaging system 100 may further include a data acquisition device 160 , the central control device 170 may further be connected in communication with the data acquisition device 160 to control the data acquisition device 160 .

[0110] Figure 7 FIG. 2 is a block diagram showing another example of a holographic imaging system 100 according to the present disclosure. Figure 7 As shown, the holographic imaging system 100 further includes a radio frequency receiving device 150 and a data acquisition device 160, and the central control device 170 is communicatively connected with the radio frequency transmitting device 110, the data processing device 130, the display device 140, the radio frequency receiving device 150 and the data acquisition device 160 respectively.

[0111] The above describes specific embodiments of the present disclosure. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0112] Not all steps and units in the above-mentioned processes and system structure diagrams are necessary, and some steps or units can be ignored according to actual needs. The execution order of each step is not fixed and can be determined according to needs. The device structure described in the above-mentioned embodiments can be a physical structure or a logical structure, that is, some units may be implemented by the same physical entity, or some units may be implemented by multiple physical entities, or some components in multiple independent devices may be implemented together.

[0113] The term "exemplary" as used throughout this disclosure means "serving as an example, instance, or illustration" and does not imply "preferred" or "advantageous" over other embodiments. The detailed description includes specific details for the purpose of providing an understanding of the described techniques. However, the techniques may be practiced without these specific details. In some instances, in order to avoid obscuring the concepts of the described embodiments, well-known structures and devices are shown in block diagram form.

[0114] The optional implementation modes of the embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the embodiments of the present disclosure are not limited to the specific details in the above implementation modes; within the technical concept of the embodiments of the present disclosure, a variety of simple modifications can be made to the technical solutions of the embodiments of the present disclosure, and these simple modifications all fall within the protection scope of the embodiments of the present disclosure.

[0115] The above description of the present disclosure is provided to enable any person of ordinary skill in the art to implement or use the present disclosure. Various modifications to the present disclosure will be apparent to those of ordinary skill in the art, and the general principles defined herein may be applied to other variations without departing from the scope of protection of the present disclosure. Therefore, the present disclosure is not limited to the examples and designs described herein, but is consistent with the widest range of principles and novel features disclosed herein.

Claims

1. A holographic imaging system, comprising: A radio frequency transmitting device, an array antenna, a data processing device and a display device, wherein the array antenna comprises array elements uniformly distributed in the order of rows and columns to form an antenna array; The array antenna is communicatively connected to the radio frequency transmitting device, and the data processing device is communicatively connected to the array antenna and the display device respectively; The radio frequency transmitting device is configured to: generate a triggering electrical signal for triggering the array antenna to transmit an electromagnetic signal, and send the triggering electrical signal to the array antenna; The array antenna is configured to: determine the initial transmission frequency of each array element in response to the trigger electrical signal, wherein the working frequency band of the holographic imaging system is divided into a plurality of frequencies, the number of the plurality of frequencies is not less than the number of the array elements, each frequency is allocated to each array element as the initial transmission frequency of each array element, and the initial transmission frequencies of each array element are different; for each array element, sequentially transmit the transmission electromagnetic signals corresponding to each frequency starting from the initial transmission frequency in accordance with the specified frequency order of each frequency, wherein the frequencies of the transmission electromagnetic signals transmitted by each array element at each moment are different; and for each array element, receive the echo electromagnetic signal corresponding to the transmission electromagnetic signal emitted by the array element and the designated adjacent array element corresponding to the array element, and convert the received echo electromagnetic signal into a response electrical signal, wherein the designated adjacent array element is an array element adjacent to the array element in the antenna array and located at the designated orientation of the array element, and the transmission electromagnetic signal emitted by each array element is reflected after reaching the target area point to form the echo electromagnetic signal, and the echo electromagnetic signal is received by multiple array elements in the array antenna after propagation; The data processing device is configured to: acquire the response electrical signal, and perform imaging processing on the response electrical signal to obtain an imaging image; The display device is configured to display the imaging image.

2. The holographic imaging system according to claim 1, wherein: The array antenna is arranged to include a plurality of sub-arrays, each sub-array is evenly distributed in the order of rows and columns, each sub-array includes a plurality of array elements, and all array elements in each sub-array are evenly distributed in the order of rows and columns. The designated adjacent array element of each array element is an array element that is adjacent to the array element in the sub-array to which the array element belongs and is located at a designated position of the array element.

3. The holographic imaging system according to claim 1 or 2, wherein: The specified location includes: above, right, and upper right; above, left, and upper left; below, to the left, and to the lower left; or Below, right, and lower right.

4. The holographic imaging system according to claim 1, wherein: The specified frequency sequence includes a closed-loop sequence of increasing frequencies or a closed-loop sequence of decreasing frequencies.

5. The holographic imaging system according to claim 1, wherein: The array antenna is also configured as: For each array element, the transmitting electromagnetic signals corresponding to each frequency are transmitted in sequence starting from the initial transmitting frequency according to the specified frequency order of each frequency, until the transmitting electromagnetic signals corresponding to all frequencies are transmitted once.

6. The holographic imaging system according to claim 1, wherein: The array antennas are arranged into a linear array or a planar array.

7. The holographic imaging system according to claim 1, further comprising: A radio frequency receiving device, the radio frequency receiving device is communicatively connected with the radio frequency transmitting device, the array antenna and the data processing device, The radio frequency receiving device is configured to: obtain the response electrical signal from the array antenna, perform specified data processing on the response electrical signal, and send the processed response electrical signal to the data processing device, wherein the specified data processing includes at least one of amplification processing, mixing processing and filtering processing.

8. The holographic imaging system according to claim 1, further comprising: a data acquisition device, the data acquisition device being communicatively connected with the data processing device, The data acquisition device includes at least one sensor selected from the group consisting of a camera, a temperature sensor, and a metal detector.

9. The holographic imaging system according to claim 1, wherein: The data processing device is further configured to: Rearranging the acquired response electrical signals in order of frequency in array elements to obtain re-arranged response electrical signals; as well as The reordered response electrical signals are imaged to obtain an imaging image.

10. The holographic imaging system according to claim 1, wherein: The data processing device is further configured to: The private part of the target object in the image is blurred.

11. The holographic imaging system according to claim 1, further comprising: A central control device is communicatively connected with the radio frequency transmitting device, the data processing device, and the display device respectively.

12. The holographic imaging system according to claim 1, wherein: The holographic imaging system is applied to security inspection equipment.

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