A ToF measuring device and a measuring method

Abstract

The application relates to the technical field of measurement, in particular to a ToF measurement device and a measurement method. The measurement device comprises a data processing unit and a plurality of ToF measurement units, the edges of the field angles of adjacent ToF measurement units are overlapped by a set angle to form an overlapping area and a non-overlapping area of the fields of adjacent ToF measurement units; the data processing unit is signal-connected with the plurality of ToF measurement units, is used for judging that a target is located in the overlapping area or the non-overlapping area of the fields of adjacent ToF measurement units according to the ranging results of the ToF measurement units, and outputting the position information of the target. The measurement method comprises the following steps: obtaining the ranging results of the ToF measurement units; judging that a target is located in the overlapping area or the non-overlapping area of the fields of adjacent ToF measurement units according to the ranging results of the ToF measurement units. The scheme can solve the problems that in the prior art, in order to improve the resolution of the azimuth, the number of measurement channels is increased, the structure of the whole measurement device is complex, and the cost is sharply increased.

Description

Technical Field

[0001] This invention relates to the field of measurement technology, and specifically to a ToF measurement device and method. Background Technology

[0002] Time-of-flight (ToF) ranging is a two-way ranging technique that primarily uses the time it takes for a signal to travel back and forth between two asynchronous transceivers (or reflected surfaces) to measure the distance between nodes.

[0003] like Figure 1 As shown, all ToF measurement systems have a field of view (FOV). ToF measurement systems can only measure targets within the FOV, but the field of view has a certain range, and ToF measurement systems cannot identify the position of targets outside the field of view.

[0004] To increase the field of view (FOV) of Time-of-Flight (ToF) systems, existing technologies expand single-channel ToF systems into multi-channel systems. This involves stitching together the FOVs of multiple single-channel ToF systems to create a larger multi-channel ToF FOV. Each channel measures the distance to targets within its respective FOV, and targets within the same FOV are considered to be in the same direction. This allows for the measurement of multiple targets or the outlines of larger targets. However, while existing multi-channel ToF systems increase the FOV, they cannot overcome the poor angular resolution of single-channel ToF systems. Specifically, they struggle to determine the azimuth of targets within each channel's FOV, making accurate localization impossible. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a ToF measurement device and measurement method, which can solve the problem that the existing technology cannot overcome the poor angular resolution of single-channel ToF systems, making it difficult to distinguish the orientation of targets within the FOV of each channel and thus unable to achieve accurate positioning.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] On one hand, the present invention provides a ToF measurement device, comprising:

[0008] Multiple ToF measurement units are used, and the edges of the field of view of adjacent ToF measurement units overlap by a set angle to form overlapping and non-overlapping areas of the field of view of adjacent ToF measurement units;

[0009] The data processing unit is signal-connected to the multiple ToF measurement units and is used to determine whether the target is located in the overlapping or non-overlapping area of ​​the field of view of adjacent ToF measurement units based on the ranging results of each ToF measurement unit, and output the target's position information.

[0010] In some alternative solutions, the set angle is 1 / 3 of the field of view of the ToF measurement unit.

[0011] In some alternative solutions, the ToF measurement unit employs a single-photon ranging / imaging sensor.

[0012] On the other hand, the present invention also provides a ToF measurement method, comprising the following steps:

[0013] Obtain the ranging results of each ToF measurement unit;

[0014] Based on the ranging results of each ToF measurement unit, it is determined whether the target is located in the overlapping or non-overlapping area of ​​the field of view of adjacent ToF measurement units.

[0015] In some optional solutions, determining whether the target is located within the overlapping or non-overlapping area of ​​the fields of view of adjacent ToF measurement units based on the ranging results of each ToF measurement unit includes:

[0016] If a target exists in the field of view of a certain ToF measurement unit, and there is no target in the field of view of the adjacent ToF measurement units, then the target is determined to be located in the non-overlapping region of the field of view of the corresponding ToF measurement unit.

[0017] If a target exists in the field of view of a certain ToF measurement unit, and a target also exists in the field of view of any adjacent ToF measurement unit, then based on the target distance within the field of view of the adjacent ToF measurement units, it is determined whether the target is located in the overlapping or non-overlapping area of ​​the field of view of the adjacent ToF measurement units.

[0018] In some optional solutions, determining whether a target is located within the overlapping or non-overlapping area of ​​the fields of view of adjacent ToF measurement units based on the target distance within the field of view of adjacent ToF measurement units includes:

[0019] First-class targets are selected from all adjacent ToF measurement units whose distance difference is less than or equal to a set difference. The centrality of the ranging result data corresponding to each group of first-class targets whose distance difference is less than or equal to the set difference is compared to determine whether the first-class targets are located in the overlapping or non-overlapping area of ​​the field of view of the adjacent ToF measurement units. The centrality of the ranging result data indicates the degree of concentration of the ranging result data within the set distance range.

[0020] A second type of target is selected, whose distance difference with all targets in the adjacent ToF measurement units is greater than a set difference. The second type of target is determined to be located in the non-overlapping area of ​​the respective fields of view of the adjacent ToF measurement units.

[0021] In some optional solutions, the step of comparing the centrality of the ranging results data corresponding to each group of first-type targets whose distance difference within adjacent ToF measurement units is less than or equal to a set difference, and determining whether the first-type targets are located in the overlapping or non-overlapping areas of the fields of view of adjacent ToF measurement units, includes:

[0022] If the centrality of the ranging results data of each first type of target whose distance difference is less than or equal to the set difference is greater than the first preset threshold, then the first type of target is determined to be located in the non-overlapping area of ​​the field of view of each adjacent ToF measurement unit, or the two first type of targets are determined to be a continuous target located in the overlapping area and non-overlapping area of ​​the field of view of adjacent ToF measurement units.

[0023] If the centrality of the ranging result data corresponding to the first type of target whose distance difference is less than or equal to the set difference is less than or equal to the first preset threshold, then the first type of target is determined to be a common target located in the overlapping area of ​​the fields of view of adjacent ToF measurement units, or two targets located in the overlapping areas of the fields of view of adjacent ToF measurement units that are far apart from each other.

[0024] In some alternative schemes, the determination of the first type of target as a common target located within the overlapping area of ​​the fields of view of adjacent ToF measurement units, or as two targets located in mutually distant overlapping areas within their respective fields of view of adjacent ToF measurement units, includes:

[0025] If there are first-type targets in the field of view of another ToF measurement unit adjacent to each other, and the distance difference is less than or equal to a set difference, and the concentration of the ranging result data is less than or equal to a first preset threshold, then the first-type targets in the field of view of the adjacent ToF measurement units are two targets in the overlapping area of ​​the field of view of the adjacent ToF measurement units and the field of view of another ToF measurement unit adjacent to each other.

[0026] If there is no first-type target in the field of view of another ToF measurement unit adjacent to each other, and the distance difference is less than or equal to a set difference, and the concentration of the ranging result data is less than or equal to a first preset threshold, then the first-type target in the field of view of the adjacent ToF measurement units is a common target in the overlapping area of ​​the field of view of the adjacent ToF measurement units.

[0027] In some alternative schemes, when the first type of target is determined to be a common target located in the overlapping area of ​​the fields of view of adjacent ToF measurement units, the position of the common target in the overlapping area is determined based on the concentration of the ranging results data of the common target in the fields of view of the two adjacent ToF measurement units.

[0028] In some alternative schemes, the ranging result includes photon flight time and photon count information, and the data concentration of the ranging result indicates the degree of concentration of photon count information corresponding to all photon flight times within a set time range, including the photon flight time corresponding to the target.

[0029] Compared with existing technologies, the advantages of this invention are as follows: This solution sets an angle for the overlap between the fields of view of adjacent ToF measurement units. During detection, the distance measurement results of each ToF measurement unit can be used to determine whether the target is located within the overlapping or non-overlapping area of ​​the fields of view of adjacent ToF measurement units, thereby improving the angular resolution capability of the ToF measurement device and enabling more specific identification of the target's location. Setting an angle for the overlap between the fields of view of adjacent ToF measurement units is equivalent to increasing the detection channels of the measurement device, that is, increasing the new detection channels formed by the overlapping area. Without increasing the number of ToF hardware channels, the number of ToF channels is increased, the channel density of ToF is improved, the angular resolution capability is enhanced, and the specific location of the target within the FOV is identified. Assuming the number of hardware channels is N, the actual number of detection channels is N + (N-1) = 2N-1, where N-1 represents the number of overlapping areas. The detection device can identify the position of the target within the 2N-1 detection channel area by having N hardware channels, thus improving the angular resolution of the detection device. Compared to the existing technology, which requires 2N-1 hardware channels to form 2N-1 detection channels, this solution can reduce the number of hardware channels, thereby saving costs. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of a single-channel ToF measurement device;

[0032] Figure 2 This is a schematic diagram of the structure of a multi-channel ToF measurement system;

[0033] Figure 3 A schematic diagram of the measurement data for each channel;

[0034] Figure 4 This is a schematic diagram of the structure of a multi-channel ToF measurement device;

[0035] Figure 5 A schematic diagram of the field of view (FOV) measured by the ToF measurement unit;

[0036] Figure 6 This is a schematic diagram of the ToF measurement device in an embodiment of the present invention;

[0037] Figure 7 This is a schematic diagram of the ranging results of each ToF measurement unit in the implementation of this invention. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0040] like Figure 6 As shown, in one aspect, the present invention provides a ToF measurement device, including: a data processing unit and a plurality of ToF measurement units, wherein the edges of the field of view of adjacent ToF measurement units overlap by a set angle to form an overlapping area and a non-overlapping area of ​​the field of view of adjacent ToF measurement units; the data processing unit is signal-connected to the plurality of ToF measurement units and is used to determine whether the target is located in the overlapping area or the non-overlapping area of ​​the field of view of adjacent ToF measurement units according to the ranging results of each ToF measurement unit, and output the position information of the target.

[0041] When using this Time-of-Flight (ToF) measuring device for distance measurement, lasers are emitted into the field of view of all ToF measuring units. The edges of the field of view angles of adjacent ToF measuring units overlap by a set angle, forming overlapping and non-overlapping areas of the field of view of adjacent ToF measuring units. During detection, the distance measurement results of each ToF measuring unit can be used to determine whether the target is located in the overlapping or non-overlapping area of ​​the field of view of adjacent ToF measuring units. This is equivalent to increasing the detection channels of the measuring device, thereby improving the angular resolution of the detection device and enabling more specific identification of the target's location.

[0042] like Figure 1 As shown, all ToF measurement systems have a field of view (FOV). A ToF measurement system can only measure targets within the FOV, but the FOV has a limited range, meaning the ToF measurement system cannot identify the position of targets outside the FOV. Figure 2 and Figure 4As shown, to increase the field of view (FOV) of a Time-of-Flight (ToF) measurement system, existing solutions expand a single-channel ToF system into a multi-channel system. Each channel measures the distance to targets within its respective FOV. Targets within the same FOV are considered to be in the same direction, allowing for the measurement of multiple targets or the outline of larger targets. While general multi-channel ToF systems increase the FOV, they cannot overcome the poor angular resolution of single-channel ToF systems, meaning it's difficult to determine the orientation of targets within each channel's FOV, hindering accurate positioning. To improve angular resolution, existing solutions narrow the FOV of each measurement channel and employ more measurement channels. Multi-channel ToF technology uses multiple detectors, with a router sending channel information to indicate which detector the detected photons originated from. Each channel can obtain the temporal distribution of the signal. Simultaneous operation of all channels not only improves counting efficiency and saves detection time but also provides more comprehensive signal information. Photons detected by each ToF measurement unit are recorded in its corresponding channel. The photon pulses are timed by the time measurement module. The ToF measurement unit number serves as the ToF channel number. Signals detected by different ToF measurement units are transmitted to their respective time storage units, such as... Figure 3 As shown.

[0043] However, in existing solutions, each ToF measurement unit's measurement channel corresponds to a set of hardware, such as... Figure 4 As shown, there are three fields of view (FOV), each corresponding to a set of hardware channels (not shown in the figure). Each measurement channel requires a separate set of hardware, which complicates the overall structure of the measurement device and significantly increases its cost. A single hardware channel consists of a set of components (including a laser emitting element, SPAD detection element, etc.) capable of independently performing laser emission and reception detection, i.e., the "ToF measurement unit" described in this solution. Figure 5 As shown, the FOV of the hardware channel includes the emission field of view and the detection field of view. In practical applications, since the interval between the laser emission element and the SPAD detection element (i.e., the distance between points A and B) is much smaller than the distance d from the target object to the ranging device, points A and B can be regarded as coincident. Their corresponding emission field of view and detection field of view are also regarded as coincident. Therefore, the FOV of the hardware channel refers to the emission field of view and detection field of view regarded as coincident, that is, one field of view.

[0044] This solution sets an overlap angle between the fields of view of adjacent ToF measurement units, which is equivalent to increasing the detection channels of the measurement device. That is, it adds new detection channels formed by the overlapping area. Assuming the number of hardware channels is N, the actual number of detection channels is N + (N-1) = 2N-1, where N-1 represents the number of overlapping areas. The detection device can identify the position of the target within the 2N-1 detection channel area by having N hardware channels, thereby improving the angular resolution of the detection device. Compared with the existing technology, which requires 2N-1 hardware channels to form 2N-1 detection channels, this solution can reduce the number of hardware channels from another perspective, thus saving costs.

[0045] In some optional embodiments, the angle is set to 1 / 3 of the field of view angle of the ToF measurement unit.

[0046] In this example, the overlap angle between the fields of view of adjacent ToF measurement units is designed to be 1 / 3 of the field of view angle of a single ToF measurement unit. This ensures that the detection channel (field of view channel) in the middle has the same overlap angle between the fields of view of adjacent ToF measurement units and the same angle between the two overlapping areas. In other words, a field of view is divided into three equal parts. In addition to achieving orientation resolution of the target, this also presents a more uniform imaging effect, thereby improving the accuracy of detection.

[0047] Of course, in other embodiments, the angle of the overlapping area can also be other angles, which can also improve the resolution of the detection device. For example, the field of view of the first hardware channel overlaps with the field of view of the second hardware channel by 2 / 3, the field of view of the first hardware channel overlaps with the field of view of the third hardware channel by 1 / 3, the field of view of the second hardware channel overlaps with the field of view of the third hardware channel by 2 / 3, and so on. By adopting such an overlapping method, the resolution of the entire device can be further improved.

[0048] In some optional embodiments, the ToF measurement unit employs a single-photon ranging / imaging sensor. In this example, a single-photon ranging / imaging sensor, namely a dToF ranging / imaging sensor, is used. Unlike existing iToF (indirect time-of-flight) sensors, dToF has higher photon sensitivity (single-photon sensitivity), which can be combined with improved angular resolution to achieve accurate ranging and orientation determination, or to achieve low-light imaging.

[0049] like Figure 6 As shown, on the other hand, the present invention provides a ToF measurement method, implemented using the above-mentioned ToF measurement device, comprising the following steps:

[0050] Obtain the ranging results of each ToF measurement unit;

[0051] Based on the ranging results of each ToF measurement unit, it is determined whether the target is located in the overlapping or non-overlapping area of ​​the field of view of adjacent ToF measurement units.

[0052] This solution sets an overlap angle between the fields of view of adjacent ToF measurement units. During detection, the distance measurement results of each ToF measurement unit can be used to determine whether the target is located in the overlapping or non-overlapping area of ​​the fields of view of adjacent ToF measurement units, thereby improving the angular resolution capability of the detection device. This is equivalent to increasing the detection channels of the measurement device, i.e., adding new detection channels formed by overlapping areas, which can more specifically identify the location of the target. Assuming the number of hardware channels is N, the actual number of detection channels is N + (N-1) = 2N-1, where N-1 represents the number of overlapping areas. The detection device can identify the position of the target within the area of ​​2N-1 detection channels with N hardware channels, improving the resolution of the detection device. Compared with the existing technology that requires 2N-1 hardware channels to form 2N-1 detection channels, this reduces the number of hardware channels and saves costs.

[0053] In some optional embodiments, based on the ranging results of each ToF measurement unit, determining whether the target is located within the overlapping or non-overlapping area of ​​the fields of view of adjacent ToF measurement units includes:

[0054] If a target exists in the field of view of a certain ToF measurement unit, and no target exists in the field of view of the adjacent ToF measurement units, then the target is located in the non-overlapping region of the field of view of the corresponding ToF measurement unit.

[0055] If a target exists in the field of view of a certain ToF measurement unit, and a target also exists in the field of view of any adjacent ToF measurement unit, it is determined that the target is located in the overlapping area or non-overlapping area of ​​the fields of view of the adjacent ToF measurement units.

[0056] In this embodiment, the presence of a target within the field of view of the ToF measurement unit can be determined by statistical analysis of the photon data detected by the ToF measurement unit. Specifically, when a target is present in the field of view, the photon data detected by the ToF measurement unit will show a concentrated distribution trend over time. The distribution center can represent the distance to the target, and more importantly, the presence of the target. If the photon data is presented in a photon time-of-flight statistical histogram, it will show a "peak" corresponding to the distribution center in the histogram. The horizontal axis corresponding to this peak in the histogram can also represent the distance to the target, and more importantly, the presence of the target.

[0057] In some optional embodiments, during measurement, each ToF measurement unit receives detection data. When the detection data of a certain ToF measurement unit shows that a target exists within the field of view of that ToF measurement unit, but no target exists within the field of view of its adjacent ToF measurement units, it can be determined that the target is located within a non-overlapping region within the field of view of the ToF measurement unit. Such a target can be called an "isolated target". In this example, the determination is made for all adjacent ToF measurement units.

[0058] In this embodiment, "isolated targets" can be identified by iterating through groups of two or three adjacent ToF measurement units, using the ToF measurement unit number as an index.

[0059] For example, a ToF measurement device may include three ToF measurement units numbered 1, 2, and 3, corresponding to fields of view (FOV1, FOV2, and FOV3), respectively. First, it checks if an "isolated target" exists within FOV1. Specifically, it first checks if a target exists within FOV1. If a target exists within FOV1, it checks if a target exists within FOV2. If no target exists in FOV2, the target in FOV1 is considered an "isolated target." Following this process, it checks if an "isolated target" exists within FOV2. If a target exists within FOV2, it checks if a target exists within FOV1 and FOV3. If no target exists in either FOV1 or FOV3, the target is considered an "isolated target" within FOV2. This process continues until all measurement units have been checked.

[0060] It should be noted that when using a traversal order for judgment, the determination of whether the next group of adjacent ToF measurement units needs to be judged for "isolated targets" can be based on the judgment result of whether there is an "isolated target" in the previous group of adjacent ToF measurement units. For example, if an "isolated target" is judged to exist in FOV1, it means that there is no target in FOV2. Therefore, when judging the field of view of the adjacent ToF measurement units FOV2 and FOV3, the repeated judgment of FOV2 can be omitted, and it is only necessary to judge whether there is an "isolated target" in the field of view of FOV3.

[0061] In other embodiments, more ToF measurement units may be included, numbered 1, 2, 3...n, where the number of n can be determined according to actual measurement needs, and this application does not impose specific limitations. Alternatively, all targets can be searched directly, and it can be determined whether the target is located within the non-overlapping region of the field of view of the corresponding ToF measurement unit by judging whether there is a target within the field of view of the adjacent ToF measurement units of any target.

[0062] For example, suppose that the field of view (FOV1) of the first ToF measurement unit, the field of view (FOV2) of the second ToF measurement unit, and the field of view (FOV3) of the third ToF measurement unit are consecutive adjacent fields of view of ToF measurement units. When judging the target in the FOV1 of the first ToF measurement unit and the FOV2 of the second ToF measurement unit, if the target exists only in the field of view (FOV2), then it is judged that the target is located in the non-overlapping area of ​​the field of view (FOV2) relative to the field of view (FOV1).

[0063] If there are targets in the fields of view of adjacent ToF measurement units, it is also necessary to determine whether the target is located in the overlapping or non-overlapping area of ​​the fields of view of the adjacent ToF measurement units by the target distance in the fields of view of the adjacent ToF measurement units.

[0064] In this example, the precise location of an isolated target within the field of view of one of the two adjacent ToF measurement units can be determined relatively accurately, provided that only one target exists within the field of view of the other two ToF measurement units. This isolated target is located in the non-overlapping area of ​​the ToF measurement unit's field of view. Compared to traditional methods, this method of overlapping the fields of view of adjacent ToF measurement units improves the angular resolution for such isolated targets.

[0065] In some optional embodiments, determining whether a target is located within the overlapping or non-overlapping area of ​​the fields of view of adjacent ToF measurement units based on the target distance within the field of view of adjacent ToF measurement units includes:

[0066] First-class targets with distance differences less than or equal to a set difference within adjacent ToF measurement units are selected. The centrality of the ranging result data corresponding to each group of first-class targets with distance differences less than or equal to the set difference is compared to determine whether the first-class targets are located in the overlapping or non-overlapping area of ​​the field of view of the adjacent ToF measurement units. The centrality of the ranging result data indicates the degree of concentration of the ranging result data within the set distance range.

[0067] A second type of target is selected, whose distance difference with all targets in the adjacent ToF measurement units is greater than a set difference. The second type of target is determined to be located in the non-overlapping area of ​​the respective fields of view of the adjacent ToF measurement units.

[0068] In this embodiment, the first type of target refers to any two targets randomly selected from those detected by two adjacent ToF measurement units, where one target is located within the field of view of one ToF measurement unit and the other target is located within the field of view of another ToF measurement unit, and the distance difference between these two targets is less than or equal to a set difference. The second type of target refers to targets whose distance difference with all targets within adjacent ToF measurement units is greater than a set difference. One target is located within the field of view of one ToF measurement unit, and the other target is located within the field of view of another adjacent ToF measurement unit, and the distance difference between these two targets is greater than a set difference.

[0069] When a target with a distance difference smaller than a set difference is detected within the field of view of adjacent ToF measurement units, two situations may occur:

[0070] Scenario 1: A common target exists within the overlapping area of ​​the fields of view of adjacent ToF measurement units;

[0071] Scenario 2: Each of the non-overlapping areas of the fields of view of adjacent ToF measurement units contains a target at the same or similar distance. Therefore, targets within the fields of view of adjacent ToF measurement units are classified as Category I targets if the distance difference is less than or equal to a set value. After identifying Category I targets, the concentration of ranging results for each group of Category I targets is compared to determine whether the Category I targets are located within the overlapping or non-overlapping areas of the fields of view of the adjacent ToF measurement units.

[0072] There may be multiple groups of first-class targets whose distance difference within the field of view of adjacent ToF measurement units is less than the set difference. Therefore, when comparing the centrality of the ranging results data corresponding to the first-class targets, the comparison is based on the distance difference being less than or equal to the set difference.

[0073] For example, if a target at a distance of 0.5m and a target at a distance of 1m are detected in the field of view of the first ToF measurement unit, and a target at a distance of 0.5m and a target at a distance of 1m are also detected in the field of view of the adjacent second ToF measurement unit, then the two targets at a distance of 0.5m are grouped together, and the two targets at a distance of 1m are grouped together.

[0074] In this embodiment, a second type of target where the distance difference between all targets within adjacent ToF measurement units is greater than a set difference indicates that the second type of target will not be located within the overlapping area of ​​the adjacent ToF measurement units. This is because if a target were located within the overlapping area of ​​the field of view, both adjacent ToF measurement units would detect the target, and the distance difference between the detected target within the two adjacent fields of view would be less than or equal to the set difference. This does not meet the requirement that the distance difference between the target and all targets within adjacent ToF measurement units must be greater than the set difference, and therefore the target would not be classified as a second type of target. Therefore, it can be determined that the second type of target is located within the non-overlapping area of ​​the respective fields of view of the adjacent ToF measurement units.

[0075] For example, such as Figure 6 As shown, the field of view (FOV1) of the first ToF measurement unit and the field of view (FOV2) of the second ToF measurement unit are the two fields of view of adjacent ToF measurement units. Target B is a target located within the overlapping area of ​​FOV1 and FOV2, target A is a target located within the non-overlapping area of ​​FOV1, and target C is a target located within the non-overlapping area of ​​FOV2. During detection, two targets A and B will be detected within FOV1, and two targets C and B will be detected within FOV2.

[0076] When filtering out the first type of targets in FOV1 and FOV2 whose distance difference is less than or equal to the set difference, target B detected in FOV1 and FOV2 has a distance difference less than or equal to the set difference and is filtered out for the next step of judgment.

[0077] When filtering out second-class targets whose distance differences with all adjacent ToF measurement units are greater than a set difference, Figure 6 For example, first, targets A and B within FOV1 are judged. Target A within FOV1 has a distance that is not equal to and greater than a set difference between it and targets B and C within FOV2, thus it is judged as a second-type target. Target A within FOV1 has a distance difference less than or equal to a set difference between it and targets B within FOV2, failing to meet the requirement that the distance difference with all targets in adjacent ToF measurement units is greater than a set difference, therefore it is not judged as a second-type target. Then, when judging targets B and C within FOV2, the distance difference between them is... Comparing targets B and C in FOV2 with targets A in FOV1, B and C in FOV2, and D in FOVD, we find that the distances between target C in FOV2 and targets A in FOV1, B and C in FOV2, and D in FOVD are all unequal and greater than the set difference. Therefore, they will be classified as second-type targets. Thus, targets A and C cannot be the same targets in the overlapping area of ​​the fields of view of adjacent ToF measurement units. It can be determined that targets A and C are located in the non-overlapping area of ​​the corresponding fields of view.

[0078] In this embodiment, the specific locations of second-type targets with unequal or dissimilar detection distances within adjacent ToF measurement units can be determined relatively accurately. These second-type targets are located in the non-overlapping areas of their corresponding ToF measurement unit's field of view. Compared to traditional methods, this method of overlapping the fields of view of adjacent ToF measurement units improves the angular resolution for second-type targets.

[0079] In this example, the set difference can be set according to the calibration settings, or the set difference can be directly set to 0.

[0080] In some optional embodiments, the centrality of the ranging results data corresponding to each group of first-type targets whose distance difference within adjacent ToF measurement units is less than or equal to a set difference is compared to determine whether the first-type target is located in the overlapping or non-overlapping area of ​​the field of view of the adjacent ToF measurement units, including:

[0081] If the centrality of the ranging results data of each first type of target whose distance difference is less than or equal to the set difference is greater than the first preset threshold, then it is determined that the two first type of targets are located in the non-overlapping area of ​​the respective fields of view of the adjacent ToF measurement units, or the two first type of targets are determined to be a continuous target located in the overlapping area and non-overlapping area of ​​the fields of view of the adjacent ToF measurement units.

[0082] If the centrality of the ranging result data corresponding to the first type of target whose distance difference is less than or equal to the set difference is less than or equal to the first preset threshold, then the two first type of targets are determined to be common targets located in the overlapping area of ​​the field of view of adjacent ToF measurement units, or two targets located in the overlapping area of ​​each adjacent ToF measurement unit that are far apart from each other.

[0083] The ranging results data of the target exhibit the following patterns: In the field of view of the ToF measurement unit, the closer the target is to the center of the field of view, the more concentrated its ranging results data becomes, which means that more photons arrive and the time is concentrated, resulting in a high and narrow peak in the statistical histogram of photon count-time of flight, i.e., the greater the concentration of the ranging results data; the closer the target is to the edge of the field of view, the more dispersed its ranging results data becomes, with fewer photons arriving and the time being dispersed, resulting in a low and wide peak, and a smaller concentration of the ranging results data.

[0084] Based on the above rules, targets of the first type with a ranging result data concentration greater than a first preset threshold can be identified as either located within the non-overlapping area of ​​the respective fields of view of adjacent ToF measurement units, or as a continuous target located within the overlapping and non-overlapping areas of the fields of view of adjacent ToF measurement units. Targets of the first type with a ranging result data concentration less than or equal to the first preset threshold can be identified as either a common target located within the overlapping area of ​​the fields of view of adjacent ToF measurement units, or as two targets located within mutually distant overlapping areas of the respective fields of view of adjacent ToF measurement units. This discrimination method can relatively accurately determine the specific location of targets of the first type within adjacent ToF measurement units, that is, determine whether the targets of the first type are located within the overlapping or non-overlapping areas of the fields of view of their corresponding ToF measurement units. Compared to traditional methods, this method of overlapping the fields of view of adjacent ToF measurement units improves the angular resolution for targets of the first type.

[0085] The following is a more specific embodiment, which uses a photon count-time of flight statistical histogram to visually represent the photon detection data:

[0086] like Figure 6 and Figure 7 As shown, taking three ToF measurement units as an example, there are four targets A, B, C, and D within the fields of view of the three ToF measurement units. Among them, target B is located in the overlapping area of ​​the field of view FOV1 of the first ToF measurement unit and the field of view FOV2 of the second ToF measurement unit. Figure 7 (A) is the histogram of the ranging results of the first ToF measurement unit, as shown below. Figure 7 As shown in (A), the figure shows two wave peaks, corresponding to two targets; Figure 7 (B) is the histogram of the ranging results of the second ToF measurement unit, as shown below. Figure 7 As shown in (B), the figure shows two peaks, corresponding to two targets; Figure 7 (C) is the histogram of the ranging results of the third ToF measurement unit, as shown below. Figure 7 As shown in (C), the figure shows a wave peak, which corresponds to a target. Figure 7 The horizontal axis represents time, reflecting the distance of the target interval ranging device, while the vertical axis represents the number of photons.

[0087] The ranging results of the first ToF measurement unit and the second ToF ranging unit are analyzed. First, it is found that there are targets in both the field of view (FOV1) of the first ToF measurement unit and the field of view (FOV2) of the second ToF ranging unit. Then, targets of the first category with a distance difference less than or equal to a set difference in FOV1 and FOV2 are selected, and target B can be selected as the first category target. Second, targets of the second category in FOV1 and FOV2 whose distance difference with all targets in the adjacent ToF measurement unit is greater than the set difference are selected: target A in FOV1 and target C in FOV2. The detection distances of target A in FOV1 and target C in FOV2 are not equal, and it is determined that target A and target C are located in the non-overlapping area of ​​their respective fields of view.

[0088] Next, the position of target B is determined. In this example, the concentration of the ranging results data corresponding to target B within the field of view of the first ToF measurement unit and the second ToF ranging unit is less than the first preset threshold (the ranging results are relatively scattered). Therefore, it can be determined that the target is located in the overlapping area of ​​the first ToF measurement unit and the second ToF ranging unit, which is target B within the overlapping area of ​​the first ToF measurement unit and the second ToF ranging unit.

[0089] Using the same method, the ranging results of the second ToF measurement unit and the third ToF ranging unit were analyzed. It was found that the data concentration of the ranging results of target C in the field of view of the second ToF measurement unit and target D in the field of view of the third ToF ranging unit were both greater than the first preset threshold, and it was determined that both target C and target D were located in the non-overlapping areas of the field of view of the second ToF measurement unit and the third ToF ranging unit.

[0090] In some optional embodiments, determining the first type of target as a common target located within the overlapping area of ​​the fields of view of adjacent ToF measurement units, or as two targets located in mutually distant overlapping areas within their respective fields of view of adjacent ToF measurement units, includes:

[0091] If there are targets in the field of view of each of the adjacent ToF measurement units, where the distance difference is less than or equal to a set difference and the concentration of the ranging result data is less than or equal to a first preset threshold, then the first type of targets in the field of view of the adjacent ToF measurement units are the two targets in the overlapping area of ​​the field of view of the adjacent ToF measurement units and the field of view of each of the adjacent ToF measurement units.

[0092] If there is no target in the field of view of another ToF measurement unit adjacent to each other, and the distance difference is less than or equal to a set difference, and the concentration of the ranging result data is less than or equal to a first preset threshold, then the first type of target in the field of view of the adjacent ToF measurement units is a common target in the overlapping area of ​​the field of view of the adjacent ToF measurement units.

[0093] Specifically, two adjacent ToF measurement units are i-th ToF measurement units and i+1-th ToF measurement unit. If there is a target in the field of view of i-1-th ToF measurement unit and the field of view of i+2-th ToF measurement unit with a distance difference less than or equal to a set difference and a ranging result data concentration less than or equal to a first preset threshold, then the first type of target in the field of view of i-th ToF measurement unit and i+1-th ToF measurement unit is two targets in the overlapping area where their respective fields of view are far apart. Specifically, the first type of target in the field of view of i-th ToF measurement unit is located in the overlapping area of ​​the field of view of i-th ToF measurement unit and the field of view of i-1-th ToF measurement unit, and the first type of target in the field of view of i+1-th ToF measurement unit is located in the overlapping area of ​​the field of view of i+1-th ToF measurement unit and the field of view of i+2-th ToF measurement unit.

[0094] If there are no targets within the (i-1)th ToF measurement unit's field of view and the (i+2)th ToF measurement unit's field of view that have a distance difference less than or equal to a set difference and a ranging result data concentration less than or equal to a first preset threshold, then the first type of target within the i-th ToF measurement unit's field of view and the (i+1)th ToF measurement unit's field of view is a common target within the overlapping area of ​​the i-th ToF measurement unit's field of view and the (i+1)th ToF measurement unit's field of view.

[0095] Furthermore, if the i-th ToF measurement unit or the (i+1)-th ToF measurement unit is the outermost ToF measurement unit among all ToF measurement units, then it is only necessary to determine whether there is a target within the field of view of another ToF measurement unit whose distance difference is less than or equal to a set difference and whose ranging result data concentration is less than or equal to a first preset threshold. For example, when i=1, the adjacent ToF measurement units are the 1st and 2nd ToF measurement units. During the determination, it is only necessary to determine whether there is a target within the field of view of the 3rd ToF measurement unit whose distance difference is less than or equal to a set difference and whose ranging result data concentration is less than or equal to a first preset threshold.

[0096] In some optional embodiments, when the first type of target is determined to be a common target located in the overlapping area of ​​the fields of view of adjacent ToF measurement units, the position of the common target in the overlapping area is determined according to the magnitude of the concentration of the ranging results data of the common target in the fields of view of the two adjacent ToF measurement units.

[0097] In this embodiment, as described above, within the field of view of each ToF measurement unit, the closer the target is to the center line of the field of view, the higher the concentration of the distance-to-result data; conversely, the closer the target is to the edge of the field of view, the lower the concentration of the distance-to-result data. Based on this characteristic, the position of the target within the overlapping area can be determined by the concentration of the distance measurement results within the fields of view of two adjacent ToF measurement units. For example, for target B within the overlapping area of ​​the first ToF measurement unit and the second ToF ranging unit, the position of target B within the overlapping area can be determined by the concentration of the distance measurement results from the first ToF measurement unit and the second ToF ranging unit.

[0098] In some optional embodiments, determining the position of a common target within the overlapping area includes: when the range measurement result data concentration of the common target within the fields of view of the two ToF measurement units is the same, the common target is located in the middle of the overlapping area; when the range measurement result data concentration of the common target within the fields of view of the two ToF measurement units is different, the common target is located in the overlapping area closer to the ToF measurement unit with the larger range measurement result data concentration.

[0099] In this example, each ToF measurement unit has the same field of view angle. After two ToF measurement units overlap, the center line of the overlapping area is equidistant from the center line of the field of view of both ToF measurement units. The middle position of the overlapping area is the position within the overlapping area that is equidistant from the center line of the two adjacent FOVs, i.e., the position on the center line of the overlapping area of ​​the two ToF measurement units. If the concentration of the ranging results of the target within the field of view of the two ToF measurement units is the same, then the target can be determined to be located in the middle position of the overlapping area. When the ranging results of the target within the overlapping area are different in the field of view of the two ToF measurement units, since the closer the target is to the center line of the field of view, the higher the concentration of the ranging results, the closer the target is to the center line of the field of view of the two ToF measurement units can be used to determine which ToF measurement unit's center line the target is closer to. That is, the target is located on the side of the overlapping area closer to the ToF measurement unit with the higher concentration of the ranging results. In this example, the peak of target B in FOV2 is higher and narrower, that is, the distance result data concentration Xb2 corresponding to the second ToF measurement unit is greater than the distance result data concentration Xb1 corresponding to the first ToF measurement unit. Therefore, it is determined that target B is more biased towards FOV2.

[0100] In the above embodiments, the ranging result includes photon flight time and photon count information. The data concentration of the ranging result indicates the degree of concentration of photon count information corresponding to all photon flight times within a set time range, including the photon flight time corresponding to the target.

[0101] Preferably, the data concentration of the ranging result represents the degree of concentration of photon count information corresponding to all photon flight times within a set time range centered on the photon flight time corresponding to the target. In other embodiments, the concentration of photon count information corresponding to all photon flight times within a set time range, including the photon flight time corresponding to the target, can be determined without centering on the photon flight time corresponding to the target. The selection of the range is acceptable as long as it includes the photon flight time corresponding to the target and can reflect the concentration of photon count information within a time range near the photon flight time corresponding to the target.

[0102] In this example, the photon flight time and photon count information in the ranging result are displayed in the form of a histogram. The horizontal axis represents the photon flight time, and the vertical axis represents the photon count information. The photon flight time is the time from the emission of a photon to its return and reception, which can be converted into distance. The peak position of the photon count in the histogram formed by the photon flight time and photon count information represents the photon flight time corresponding to the target, which can be converted into distance, i.e., the distance to the target.

[0103] The concentration of ranging results is determined based on the parameters of the ranging result histogram, which include standard deviation, half-width at half-maximum (FWHM), confidence level, and histogram event count. When comparing the concentration of two ranging results, the corresponding standard deviation, FWHM, confidence level, and histogram event count are selected for comparison. In this example, the histogram event count can be understood as the sum of all photon counts in the histogram; for each photon detected, the histogram event count is incremented by 1.

[0104] In this embodiment, the concentration of the ranging results is reflected by the standard deviation, half-width at half-maximum (WHM), confidence level, and number of histogram events in the histogram. The more concentrated the distribution of the ranging results, the smaller the corresponding standard deviation, WHM, confidence level, and number of histogram events. In this example, standard deviation, WHM, confidence level, and number of histogram events are selected for comparison. In other embodiments, other parameters that can reflect the concentration of the ranging results can be used for comparison, or multiple parameters can be compared.

[0105] Furthermore, a formula can be created to characterize the degree of target offset from the center of the field of view (FOV) by the ratio / magnitude relationship of the histogram event count (or other distribution indicators). For example, assuming 'a' is the histogram event count indicator, 'a1' is the histogram event count of the FOV1 ranging result within a set time range, and 'a2' is the histogram event count of the FOV2 ranging result within a set time range, then for a target located within the overlapping area of ​​FOV1 and FOV2, the offset can be represented by a1 / (a1+a2). The larger the value, the closer it is to the center of FOV1; the smaller the value, the closer it is to the center of FOV2. Similarly, the offset can be represented by a2 / (a1+a2), with a larger value indicating a closer proximity to the center of FOV2 and a smaller value indicating a closer proximity to the center of FOV1. This provides a more accurate reflection of the target's position within the field of view, especially its positional bias within the overlapping area of ​​two adjacent ToF fields of view.

[0106] In summary, this solution sets an overlap angle between the fields of view of adjacent ToF measurement units, which is equivalent to increasing the number of detection channels in the measurement device. This means adding new detection channels formed by the overlapping area, increasing the number of ToF channels without increasing the number of hardware channels, thus improving ToF channel density, angular resolution, and the ability to pinpoint the target's exact location within the field of view. Assuming the number of hardware channels is N, the actual number of detection channels is N + (N-1) = 2N-1, where N-1 represents the number of overlapping areas. The detection device can identify the target's location within 2N-1 detection channel areas using only N hardware channels, improving the device's resolution. Compared to existing technologies that require 2N-1 hardware channels to form 2N-1 detection channels, this solution reduces the number of hardware channels, thereby saving costs.

[0107] In addition, by analyzing the distribution indicators in the ranging results statistics (including standard deviation, half width at half maximum, confidence level, number of histogram events, etc.), the target can be located more accurately, thus improving the detection accuracy.

[0108] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0109] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0110] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A ToF measuring apparatus, characterized in that, include: Multiple ToF measurement units are used, and the edges of the field of view of adjacent ToF measurement units overlap by a set angle to form overlapping and non-overlapping areas of the field of view of adjacent ToF measurement units; A data processing unit, which is signal-connected to multiple ToF measurement units, is used to determine whether the target is located in the overlapping or non-overlapping area of ​​the field of view of adjacent ToF measurement units based on the ranging results of each ToF measurement unit, and output the target's position information. Specifically, based on the ranging results of each ToF measurement unit, determining whether the target is located within the overlapping or non-overlapping area of ​​the field of view of adjacent ToF measurement units includes: If a target exists in the field of view of a certain ToF measurement unit, and there is no target in the field of view of the adjacent ToF measurement units, then the target is determined to be located in the non-overlapping region of the field of view of the corresponding ToF measurement unit. If a target exists in the field of view of a certain ToF measurement unit, and a target also exists in the field of view of any adjacent ToF measurement unit, then all targets of the first category with a distance difference less than or equal to a set difference within the adjacent ToF measurement units are selected. The centrality of the ranging result data corresponding to each group of targets of the first category with a distance difference less than or equal to the set difference within the adjacent ToF measurement units is compared to determine whether the first category targets are located in the overlapping or non-overlapping area of ​​the field of view of the adjacent ToF measurement units. The centrality of the ranging result data indicates the degree of concentration of the ranging result data within the set distance range.

2. The ToF measurement apparatus of claim 1, wherein: The set angle is 1 / 3 of the field of view of the ToF measurement unit.

3. The ToF measurement apparatus of claim 1, wherein: The ToF measurement unit uses a single-photon ranging / imaging sensor.

4. A ToF measurement method, characterized in that, Includes the following steps: Obtain the ranging results of each ToF measurement unit; Based on the ranging results of each ToF measurement unit, it is determined whether the target is located in the overlapping or non-overlapping area of ​​the fields of view of adjacent ToF measurement units, including: If a target exists in the field of view of a certain ToF measurement unit, and there is no target in the field of view of the adjacent ToF measurement units, then the target is determined to be located in the non-overlapping region of the field of view of the corresponding ToF measurement unit. If a target exists in the field of view of a certain ToF measurement unit, and a target also exists in the field of view of any adjacent ToF measurement unit, then all targets of the first category with a distance difference less than or equal to a set difference within the adjacent ToF measurement units are selected. The centrality of the ranging result data corresponding to each group of targets of the first category with a distance difference less than or equal to the set difference within the adjacent ToF measurement units is compared to determine whether the first category targets are located in the overlapping or non-overlapping area of ​​the field of view of the adjacent ToF measurement units. The centrality of the ranging result data indicates the degree of concentration of the ranging result data within the set distance range.

5. The ToF measurement method as described in claim 4, characterized in that, The step of determining whether the target is located within the overlapping or non-overlapping area of ​​the fields of view of adjacent ToF measurement units based on the ranging results of each ToF measurement unit includes: If a target exists in the field of view of a certain ToF measurement unit, and a target also exists in the field of view of any adjacent ToF measurement unit, then based on the target distance within the field of view of the adjacent ToF measurement units, it is determined whether the target is located in the overlapping or non-overlapping area of ​​the field of view of the adjacent ToF measurement units.

6. The ToF measurement method as described in claim 5, characterized in that, The method of determining whether a target is located in the overlapping or non-overlapping area of ​​the fields of view of adjacent ToF measurement units based on the target distance within the field of view of adjacent ToF measurement units includes: A second type of target is selected, whose distance difference with all targets in the adjacent ToF measurement units is greater than a set difference. The second type of target is determined to be located in the non-overlapping area of ​​the respective fields of view of the adjacent ToF measurement units.

7. The ToF measurement method as described in claim 6, characterized in that, The method of comparing the centrality of ranging results for each group of first-type targets whose distance difference within adjacent ToF measurement units is less than or equal to a set difference, and determining whether the first-type target is located in the overlapping or non-overlapping area of ​​the field of view of adjacent ToF measurement units, includes: If the centrality of the ranging results data of each first type of target whose distance difference is less than or equal to the set difference is greater than the first preset threshold, then the first type of target is determined to be located in the non-overlapping area of ​​the field of view of each adjacent ToF measurement unit, or the two first type of targets are determined to be a continuous target located in the overlapping area and non-overlapping area of ​​the field of view of adjacent ToF measurement units. If the centrality of the ranging result data corresponding to the first type of target whose distance difference is less than or equal to the set difference is less than or equal to the first preset threshold, then the first type of target is determined to be a common target located in the overlapping area of ​​the fields of view of adjacent ToF measurement units, or two targets located in the overlapping areas of the fields of view of adjacent ToF measurement units that are far apart from each other.

8. The ToF measurement method as described in claim 7, characterized in that, The determination that the first type of target is a common target located within the overlapping area of ​​the fields of view of adjacent ToF measurement units, or two targets located within mutually distant overlapping areas within their respective fields of view of adjacent ToF measurement units, includes: If there are first-type targets in the field of view of another ToF measurement unit adjacent to each other, and the distance difference is less than or equal to a set difference, and the concentration of the ranging result data is less than or equal to a first preset threshold, then the first-type targets in the field of view of the adjacent ToF measurement units are two targets in the overlapping area of ​​the field of view of the adjacent ToF measurement units and the field of view of another ToF measurement unit adjacent to each other. If there is no first-type target in the field of view of another ToF measurement unit adjacent to each other, and the distance difference is less than or equal to a set difference, and the concentration of the ranging result data is less than or equal to a first preset threshold, then the first-type target in the field of view of the adjacent ToF measurement units is a common target in the overlapping area of ​​the field of view of the adjacent ToF measurement units.

9. The ToF measurement method as described in claim 7, characterized in that, When the first type of target is determined to be a common target located in the overlapping area of ​​the fields of view of adjacent ToF measurement units, the position of the common target in the overlapping area is determined based on the concentration of the ranging results data of the common target in the fields of view of the two adjacent ToF measurement units.

10. The ToF measurement method according to any one of claims 6-9, characterized in that, The ranging result includes photon flight time and photon count information. The data concentration of the ranging result indicates the degree of concentration of photon count information corresponding to all photon flight times within a set time range, including the photon flight time corresponding to the target.

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