DTOF ranging method, device and electronic equipment for saving storage space

Abstract

This invention provides a storage-saving DTOF ranging method, apparatus, and electronic device. The original laser period is decomposed into two coprime positive integers to obtain a first exposure period and a second exposure period. The target object is exposed during the first exposure period to obtain a first histogram. The target object is then exposed again during the second exposure period to obtain a second histogram. Peak finding processing is performed on both the first and second histograms to obtain the first flight time corresponding to the highest peak in the first histogram and the second flight time corresponding to the highest peak in the second histogram. The distance information of the target object is calculated based on the linear relationship between the first exposure period, the second exposure period, the first flight time, and the second flight time. By decomposing the original laser period into two coprime exposure periods and performing two exposures to obtain the distance of the target object, the maximum laser period is reduced without affecting the ranging, thus effectively saving storage space for histogram statistics.

Description

Technical Field

[0001] This invention relates to the field of distance detection technology, and in particular to a storage-saving DTOF ranging method, apparatus and electronic device. Background Technology

[0002] DTOF (Direct Time-of-Flight) is a lidar technology that calculates distance by directly measuring the time difference between the emission and reception of a light pulse. In DTOF lidar systems, time-correlated single-photon counter (TCSPC) technology is typically used to improve detection sensitivity to the photon level, significantly reducing the lidar system's dependence on light source power. However, this method requires processing a large amount of time data from reflected photons, thus necessitating substantial memory for histogram generation. This can easily create a storage bottleneck for histogram statistics and negatively impact chip area and hardware cost. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the purpose of this invention is to provide a DTOF ranging method, device and electronic device that saves storage space, aiming to save storage space for histogram statistics and reduce product hardware costs.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] The first aspect of this invention provides a storage-saving DTOF ranging method, which includes the following steps:

[0006] The original laser period is decomposed into two coprime positive integers to obtain the first exposure period and the second exposure period.

[0007] The target object is exposed during the first exposure cycle to obtain the first histogram; the target object is exposed during the second exposure cycle to obtain the second histogram.

[0008] Peak finding processing is performed on the first histogram and the second histogram respectively to obtain the first flight time corresponding to the highest peak in the first histogram and the second flight time corresponding to the highest peak in the second histogram;

[0009] The distance information of the target object is calculated based on the linear relationship between the first exposure period, the second exposure period, the first flight time, and the second flight time.

[0010] In one embodiment, the product of the first exposure period and the second exposure period is equal to the original laser period.

[0011] In one embodiment, the step of performing peak-finding processing on the first histogram and the second histogram respectively to obtain the first flight time corresponding to the highest peak in the first histogram and the second flight time corresponding to the highest peak in the second histogram includes:

[0012] Peak finding processing is performed on the first histogram to confirm the first time bin value corresponding to the highest peak in the first histogram;

[0013] Peak finding processing is performed on the second histogram to confirm the second time bin value corresponding to the highest peak in the second histogram;

[0014] Based on the time unit corresponding to each timebox in the current histogram, the first timebox value and the second timebox value are converted into the first flight time and the second flight time, respectively.

[0015] In one embodiment, calculating the distance information of the target object based on the linear relationship between the first exposure period, the second exposure period, the first flight time, and the second flight time includes:

[0016] Based on the first exposure period, the second exposure period, the first flight time, and the second flight time, a linear equation about the flight time is constructed. The linear equation about the flight time is M1*period1+T1=M2*period2+T2=T, where period1 is the first exposure period, period2 is the second exposure period, T1 is the first flight time, T2 is the second flight time, T is the flight time of the target object detected according to the original laser period, and M1 and M2 are positive integers.

[0017] The values ​​of M1 and M2 are obtained by solving the linear equation of the flight time using a preset algorithm.

[0018] The flight time of the target object is calculated based on the value of M1 or M2, and the distance information of the target object is calculated based on the flight time of the target object.

[0019] In one embodiment, the preset algorithm is either a pilot method or a table lookup method.

[0020] In one embodiment, the method further includes:

[0021] The storage space for histogram statistics is configured based on the larger value between the first exposure period and the second exposure period.

[0022] In one embodiment, the storage space for the histogram statistics is obtained according to the following formula:

[0023] memory=(period_max / bin_width)*count_max

[0024] Wherein, memory is the storage space of the histogram statistics, period_max is the larger value between the first exposure period and the second exposure period, bin_width is the time unit corresponding to each time bin in the histogram, and count_max is the number of bits corresponding to the largest photon count value in the histogram.

[0025] A second aspect of the present invention provides a storage-saving DTOF ranging device, comprising:

[0026] The period decomposition module is used to decompose the original laser period into two coprime positive integers to obtain the first exposure period and the second exposure period.

[0027] The exposure module is used to expose the target object in the first exposure cycle to obtain the first histogram; and to expose the target object in the second exposure cycle to obtain the second histogram.

[0028] The data processing module is used to perform peak finding processing on the first histogram and the second histogram respectively to obtain the first flight time corresponding to the highest peak in the first histogram and the second flight time corresponding to the highest peak in the second histogram; and to calculate the distance information of the target object based on the linear relationship between the first exposure period, the second exposure period, the first flight time and the second flight time.

[0029] In one embodiment, the data processing module includes:

[0030] An equation construction unit is used to construct an equation for flight time based on the first exposure period, the second exposure period, the first flight time, and the second flight time. The equation for flight time is M1*period1+T1=M2*period2+T2=T, where period1 is the first exposure period, period2 is the second exposure period, T1 is the first flight time, T2 is the second flight time, T is the flight time of the target object detected according to the original laser period, and M1 and M2 are positive integers.

[0031] The solving unit is used to solve the linear equation of the flight time using a preset algorithm to obtain the values ​​of M1 and M2;

[0032] The distance calculation unit is used to calculate the flight time of the target object based on the value of M1 or M2, and to calculate the distance information of the target object based on the flight time of the target object.

[0033] A third aspect of the present invention provides an electronic device comprising a storage-saving DTOF ranging device as described above.

[0034] The beneficial effects of the present invention are as follows: It provides a DTOF ranging method, device and electronic device that saves storage space. By decomposing the original laser cycle into two coprime exposure cycles and performing two exposures, the distance information of the target object is obtained based on the linear relationship between the two exposures. The maximum laser cycle is reduced without affecting the ranging, thereby effectively saving the storage space of histogram statistics and reducing the hardware cost of the product. Attached Figure Description

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0036] Figure 1 This is a flowchart of a storage-saving DTOF ranging method in an embodiment of the present invention;

[0037] Figure 2 These are histograms obtained from exposures under different laser cycles in embodiments of the present invention.

[0038] Figure 3 This is a pulse timing diagram for different laser cycles in an embodiment of the present invention;

[0039] Figure 4 This is a structural diagram of a DTOF ranging device that saves storage space in an embodiment of the present invention. Detailed Implementation

[0040] To make the technical problems, technical solutions, and beneficial effects of the embodiments of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0041] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to that other component. Furthermore, a connection can be for both fixing and circuit connection purposes.

[0042] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention 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. Therefore, they should not be construed as limitations on the present invention.

[0043] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0044] The storage-saving DTOF ranging method provided in this invention is applied to a lidar ranging system based on time-of-flight (TOF) technology. The system includes a DTOF ranging device comprising: a period decomposition module for decomposing the original laser period into two coprime positive integers to obtain a first exposure period and a second exposure period; an exposure module for exposing the target object during the first exposure period to obtain a first histogram; exposing the target object during the second exposure period to obtain a second histogram; a data processing module for performing peak-finding processing on the first and second histograms respectively to obtain a first flight time corresponding to the highest peak in the first histogram and a second flight time corresponding to the highest peak in the second histogram; and calculating the distance information of the target object based on the linear relationship between the first exposure period, the second exposure period, the first flight time, and the second flight time.

[0045] In existing DTOF lidar systems, time-correlated single-photon counter (TCSPC) technology is generally used to improve detection sensitivity to the photon level, significantly reducing the lidar system's dependence on light source power. However, this method requires processing a large amount of time data of reflected photons, thus requiring substantial memory for histogram generation. This can easily create a storage bottleneck for histogram statistics and negatively impact chip area and hardware costs. Therefore, the following describes how to solve this problem using a DTOF ranging method applied to the aforementioned DTOF ranging device, thereby saving storage space for histogram statistics and reducing product hardware costs.

[0046] like Figure 1 As shown, Figure 1 This is a flowchart of a storage-saving DTOF ranging method according to one embodiment of the present invention. The method specifically includes the following steps:

[0047] S101. Decompose the original laser period into two coprime positive integers to obtain the first exposure period and the second exposure period.

[0048] In this embodiment, the original laser period is determined based on the maximum ranging capability of the lidar system. For example, assuming the maximum ranging capability is 10.5 meters and the original laser period is 70 ns, a laser pulse is emitted every 70 ns for ranging. Because TCSPC technology, when performing photon counts, keeps the time unit (i.e., the time width of each bin) constant, the number of time bins in each histogram is related to the laser period of the exposure. Therefore, existing TCSPC technology requires storage space configured based on 70 ns, for example, 1024 storage spaces, with each time bin being 68 ps. This embodiment, however, decomposes the original laser period into two coprime positive integers as the first and second exposure periods. This decomposes the original laser period into two coprime positive integer periods for multi-exposure ranging. Since the decomposed first and second exposure periods are necessarily shorter than the original laser period, the storage space required for histogram statistics can be effectively reduced.

[0049] In specific implementation, the product of the first exposure period and the second exposure period equals the original laser period. That is, when decomposing the original laser period, it is split according to the product, decomposing it into the product of two coprime positive integers. For example, if the original laser period is 70ns, it can be decomposed into a first exposure period of 7ns and a second exposure period of 10ns, or it can be decomposed into a first exposure period of 5ns and a second exposure period of 14ns, and so on. It is understandable that the closer the two exposure periods are during decomposition, the more beneficial it is to reduce storage space. For example, decomposing into 7ns and 10ns only requires configuring storage space according to 10ns, because 7ns corresponds to 103 storage spaces and 10ns corresponds to 147 storage spaces. When decomposing into 5ns and 14ns, because 5ns corresponds to 74 storage spaces and 14ns corresponds to 204 storage spaces, it is clear that the storage space is closer under the decomposition of 7ns and 10ns, resulting in more reasonable utilization.

[0050] Since the first and second exposure cycles after decomposition are coprime and their product is the original exposure cycle, that is, the greatest common divisor of the first and second exposure cycles is 1 and the least common multiple is the original laser cycle, it is possible to cover the complete original laser cycle when performing two exposures according to the first and second exposure cycles without any repeated or missing measurement intervals. This saves storage space while ensuring the accuracy of distance measurement.

[0051] Preferably, when decomposing the original laser cycle, in order to further reduce storage space, the original laser cycle can be decomposed into three or more coprime integers. For example, 70ns can be decomposed into 2ns, 5ns and 7ns, that is, three exposures are performed with these three exposure cycles respectively. The computational complexity will increase, but the storage space can be further reduced. The specific settings can be flexibly set according to the actual ranging requirements.

[0052] S102. Expose the target object in the first exposure cycle to obtain the first histogram; expose the target object in the second exposure cycle to obtain the second histogram.

[0053] In this embodiment, based on the first and second exposure periods obtained after decomposing the original laser period, the laser emitter is configured for exposure. The laser emitter's period is set to the first exposure period, such as 7ns, causing it to emit laser pulses at a period of 7ns. The arrival timestamps of each photon are recorded using TCSPC technology, and these timestamps are converted into a histogram. Specifically, a histogram is generated by recording the difference between the photon arrival time and the laser emission time, resulting in a first histogram. This first histogram records the distribution of photon arrival times during the first exposure, with the horizontal axis representing time (with a fixed time unit, such as 100ps as the minimum timebox width), and the vertical axis representing the photon count. Similarly, the laser emitter's period is set to the second exposure period, such as 10ns, causing it to emit laser pulses at a period of 10ns, repeating the above process to generate a second histogram. By generating two histograms for each exposure and performing further processing, a larger ranging range (up to 10.5 meters) can be achieved within a smaller storage space (e.g., 147 storage spaces), thus saving the storage space required for ranging (originally 1024 storage spaces).

[0054] S103. Perform peak finding processing on the first histogram and the second histogram respectively to obtain the first flight time corresponding to the highest peak in the first histogram and the second flight time corresponding to the highest peak in the second histogram.

[0055] In this embodiment, peak finding processing is performed on the first and second histograms obtained from two exposures. Specifically, the highest peak can be found in the first histogram using methods such as thresholding, first derivative, or local maxima, and the corresponding horizontal axis time value is recorded as the first flight time T1. Similarly, the highest peak is found in the second histogram, and the corresponding horizontal axis time value is recorded as the second flight time T2. The flight times of the two exposures are confirmed through peak finding processing and used as the ranging results of the target object under the first and second exposure cycles. Since the maximum ranging capability corresponding to the decomposed first and second exposure cycles may be less than the actual distance of the target object, the obtained results may be over-range ranging results. Therefore, the first flight time T1 and the second flight time T2 cannot be directly used as the actual flight time corresponding to the target object and require further data processing to provide an accurate data foundation for subsequent data processing.

[0056] S104. Based on the linear relationship between the first exposure period, the second exposure period, the first flight time, and the second flight time, the distance information of the target object is calculated.

[0057] In this embodiment, since the distance to the target object is fixed, regardless of the exposure period or whether the measurement exceeds the range, there is a linear relationship between the exposure period and the flight time for each exposure. Specifically, as... Figure 2 and Figure 3 As shown, taking an original laser period of 70 ns and a target distance of 5 m as an example, the traditional ranging method can obtain... Figure 2 The histogram shown in (a) has a peak corresponding to a flight time T, which is the delay between the echo pulse and the transmitted pulse with a period of 70 ns. Figure 3 The flight time T shown in (a) is approximately 33.33 ns. In this embodiment, it is decomposed into two exposures, with the first exposure period 1 being 7 ns, to obtain the following result: Figure 2 The first histogram shown in (b) has its highest peak corresponding to the first flight time T1, which is the delay between the echo pulse and the transmitted pulse with a period of 7 ns. Figure 3 As shown in (b), although the difference between the time of the first received echo pulse and the time of the first emitted pulse is still T, i.e., 33.33 ns, due to the shortened exposure period, the laser emission is reset to zero and the sensor's timing zero point is synchronized with the laser. Therefore, even if the actual flight time is T, in the first exposure period period1, the 103 storage spaces are filled 4 times. In the 5th storage, the recorded first flight time is T1, that is, the difference between the first flight time T1 and the actual flight time T is 4 first exposure periods. Similarly, the second exposure period period2 is 10 ns, and the result is as follows: Figure 2 The second histogram shown in (c) has its highest peak corresponding to the second flight time T2, which is the delay between the echo pulse and the transmitted pulse with a period of 10 ns. Figure 3 As shown in (c), during the second exposure period 2, the 147 storage spaces were filled 3 times. During the 4th storage, the recorded second flight time was T2. This second flight time T2 also differs from the actual flight time T by 3 second exposure periods.

[0058] Therefore, based on the characteristic that the distance to the target object is fixed, a linear relationship can be constructed between the first exposure period, the second exposure period, the first flight time, and the second flight time. By solving this linear relationship, the distance information of the target object can be accurately calculated. By utilizing the exposure period information and flight time information from the two exposures, a large ranging range can be achieved within a small storage space, avoiding the waste of storage space in traditional methods, while maintaining high-precision ranging capabilities.

[0059] In one embodiment, step S103 includes:

[0060] Peak finding processing is performed on the first histogram to confirm the first time bin value corresponding to the highest peak in the first histogram;

[0061] Peak finding processing is performed on the second histogram to confirm the second time bin value corresponding to the highest peak in the second histogram;

[0062] Based on the time unit corresponding to each timebox in the current histogram, the first timebox value and the second timebox value are converted into the first flight time and the second flight time, respectively.

[0063] In this embodiment, when using TCSPC technology to count the arrival times of received photons, the storage space required for each histogram is pre-divided into multiple time bin addresses based on resolution requirements. Higher resolution results in smaller time units for each time bin, allowing for more precise differentiation of each photon's arrival time. Upon receiving a photon, the TDC (Time Data Converter) confirms that the photon's arrival timestamp belongs to a specific time bin. The count value for that time bin is then incremented by 1. Finally, the time bin containing the bar with the highest photon count in the histogram corresponds to the time of flight.

[0064] Therefore, when processing the data from the two exposures, the data from the first and second histograms are read from memory respectively. Peak finding is then used to identify the first time bin value (the value corresponding to the highest peak in the first histogram) and the second time bin value (the value corresponding to the highest peak in the second histogram). Simultaneously, based on the time unit corresponding to each time bin (e.g., if the minimum bin width is 100 ps, ​​then each time bin represents a 100 ps time interval), the first and second time bin values ​​are multiplied by this time unit to obtain the corresponding first and second flight times. Accurate flight times for both exposures are obtained through time-correlated single-photon counting, providing precise flight time data for subsequent distance calculations and ensuring the sensitivity of distance detection.

[0065] In one embodiment, step S104 includes:

[0066] Based on the first exposure period, the second exposure period, the first flight time, and the second flight time, a linear equation about the flight time is constructed. The linear equation about the flight time is M1*period1+T1=M2*period2+T2=T, where period1 is the first exposure period, period2 is the second exposure period, T1 is the first flight time, T2 is the second flight time, T is the flight time of the target object detected according to the original laser period, and M1 and M2 are positive integers.

[0067] The values ​​of M1 and M2 are obtained by solving the linear equation of the flight time using a preset algorithm.

[0068] The flight time of the target object is calculated based on the value of M1 or M2, and the distance information of the target object is calculated based on the flight time of the target object.

[0069] In this embodiment, based on the fixed distance to the target object, a linear equation about the flight time is constructed using the first exposure period, the second exposure period, the first flight time, and the second flight time from the two exposures. Specifically, M1*period1 + T1 = M2*period2 + T2 = T, where period1 is the first exposure period, period2 is the second exposure period, T1 is the first flight time, T2 is the second flight time, and T is the flight time of the target object detected according to the original laser period. M1 and M2 are positive integers. Based on the characteristic that the first and second exposure periods are coprime and their product is the original laser period, M1 and M2 in the above linear equation have a unique solution. That is, when ranging using the decomposed exposure period, the first flight time T1 will differ from the true flight time T by M1 first exposure periods (period1), and the second flight time T2 will differ from the true flight time T by M2 second exposure periods (period2). The true flight time T can be calculated simply by solving for the values ​​of M1 and M2. Based on the obtained values ​​of M1 or M2, the actual flight time T of the target object can be calculated, i.e., T = M1 * period1 + T1, or T = M2 * period2 + T2. The accurate distance information of the target object can be calculated by using this flight time and the speed of light.

[0070] In practice, the preset algorithm for solving the above linear equation is either the trial-and-error method or the lookup table method. The trial-and-error method involves trying different values ​​to find a solution that satisfies the conditions. For example, either M1 or M2 is chosen as the trial variable, starting with a smaller value and gradually increasing until an integer solution that satisfies the conditions is found, such as starting with M1 = 1 and gradually increasing. Each time M1 takes a new trial value, the corresponding M2 is calculated, and it is checked whether M2 is a positive integer. If it is, the solution to the above linear equation is confirmed, and unique values ​​for M1 and M2 are obtained. The lookup table method pre-calculates and stores all possible combinations of M1 and M2. After obtaining the first and second flight times from two exposures, the matching values ​​of M1 and M2 are directly confirmed by looking up the table, thereby reducing computational complexity and improving solution efficiency.

[0071] For example, when the original laser period is 70 ns, and it is split into a first exposure period 1 (7 ns) and a second exposure period 2 (10 ns), if the target object is located at 5 m, the following can be obtained: Figure 3The pulse timing diagrams shown in (b) and (c) have a first flight time T1 of 5.33 ns and a second flight time T2 of 3.33 ns. A linear equation regarding the flight time is constructed as 7*M1 + 5.33 = 10*M2 + 3.33 ns. Solving this equation using the pilot-and-drop method or a lookup table yields M1 = 4 and M2 = 3. The corresponding flight time is calculated as 7*M1 + 5.33 = 10*M2 + 3.33 ns = 33.33 ns. Figure 3 Compared with the traditional detection method shown in (a), the flight time of the target object can also be accurately calculated, while reducing the storage space required for histogram data without affecting the accuracy of ranging.

[0072] In one embodiment, the method further includes:

[0073] The storage space for histogram statistics is configured based on the larger value between the first exposure period and the second exposure period.

[0074] In this embodiment, when performing photon count, after determining the time unit corresponding to each time box, the storage space required for each histogram is related to the number of time boxes and the maximum exposure period. The storage space for histogram statistics is configured according to the maximum exposure period value after decomposition. Specifically, the storage space is confirmed according to the format memory = (period_max / bin_width) * count_max, where period_max is the larger value between the first exposure period and the second exposure period, bin_width is the time unit corresponding to each time box in the histogram, and count_max is the number of bits corresponding to the maximum photon count value in the histogram.

[0075] Specifically, assuming each timebox in the histogram corresponds to a time unit of 100ps, and the maximum photon count in the histogram is 1023, corresponding to 10 bits (i.e., the number of bits per storage space), if the histogram is statistically analyzed using traditional TCSPC technology, the storage space required for the original laser cycle of 70ns is (70ns / 100ps)*10bit = 700*10bit. After decomposing it into coprime 7ns and 10ns, only the storage space required for 10ns needs to be configured, and the required storage space is (10ns / 100ps)*10bit = 100*10bit (100 storage spaces). The ranging performance under a 70ns laser cycle can still be achieved, i.e., the maximum ranging distance of 10.5m. This greatly saves storage space while maintaining ranging performance, further saving chip area.

[0076] It should be noted that there is no necessary order between the above steps. Those skilled in the art will understand from the description of the embodiments of the present invention that the above steps may have different execution orders in different embodiments, that is, they may be executed in parallel or in turn, etc.

[0077] The present invention also provides a storage-saving DTOF ranging device, such as... Figure 4 As shown, Figure 4 The diagram illustrates the structure of a space-saving DTOF ranging device in one embodiment of the invention. It includes a period decomposition module 401, an exposure module 402, and a data processing module 403, which are sequentially connected. The period decomposition module 401 decomposes the original laser period into two coprime positive integers, obtaining a first exposure period and a second exposure period. The exposure module 402 exposes the target object during the first exposure period to obtain a first histogram; it then exposes the target object during the second exposure period to obtain a second histogram. The data processing module 403 performs peak-finding processing on the first and second histograms respectively to obtain a first flight time corresponding to the highest peak in the first histogram and a second flight time corresponding to the highest peak in the second histogram; and calculates the distance information of the target object based on the linear relationship between the first exposure period, the second exposure period, the first flight time, and the second flight time. Since the above method embodiment has already described the space-saving DTOF ranging process in detail, please refer to the corresponding method embodiment above for further details; it will not be repeated here.

[0078] In one embodiment, the data processing module 403 includes: an equation construction unit, a solution unit, and a distance calculation unit, which are connected sequentially. The equation construction unit is used to construct an equation for flight time based on the first exposure period, the second exposure period, the first flight time, and the second flight time. The equation for flight time is M1*period1+T1=M2*period2+T2=T, where period1 is the first exposure period, period2 is the second exposure period, T1 is the first flight time, T2 is the second flight time, T is the flight time of the target object detected according to the original laser period, and M1 and M2 are positive integers. The solution unit is used to solve the linear equation for flight time using a preset algorithm to obtain the values ​​of M1 and M2. The distance calculation unit is used to calculate the flight time of the target object based on the value of M1 or M2, and calculate the distance information of the target object based on the flight time of the target object. Since the above method embodiments have already described the storage-saving DTOF ranging process in detail, please refer to the corresponding method embodiments above for details, and will not be repeated here.

[0079] The present invention also provides an electronic device comprising a storage-saving DTOF ranging device as described above. Since the storage-saving DTOF ranging process has been described in detail in the above method embodiments, please refer to the corresponding method embodiments above for details, and will not be repeated here.

[0080] In summary, this invention provides a storage-saving DTOF ranging method, apparatus, and electronic device. The method includes: decomposing the original laser period into two coprime positive integers to obtain a first exposure period and a second exposure period; exposing a target object during the first exposure period to obtain a first histogram; exposing the target object during the second exposure period to obtain a second histogram; performing peak-finding processing on the first and second histograms respectively to obtain a first flight time corresponding to the highest peak in the first histogram and a second flight time corresponding to the highest peak in the second histogram; and calculating the distance information of the target object based on the linear relationship between the first exposure period, the second exposure period, the first flight time, and the second flight time. By decomposing the original laser period into two coprime exposure periods and performing two exposures, the distance information of the target object is obtained based on the linear relationship between the two exposures. This reduces the maximum laser period without affecting ranging, thereby effectively saving storage space for histogram statistics and reducing product hardware costs.

[0081] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several equivalent substitutions or obvious modifications can be made without departing from the concept of the present invention, and all such modifications, achieving the same performance or purpose, should be considered within the scope of protection of the present invention.

Claims

1. A DTOF ranging method for saving storage space, characterized in that, Includes the following steps: The original laser period is decomposed into two coprime positive integers to obtain the first exposure period and the second exposure period. The product of the first exposure period and the second exposure period is equal to the original laser period. The target object is exposed during the first exposure cycle to obtain the first histogram; The target object is exposed during the second exposure cycle to obtain the second histogram; Peak finding processing is performed on the first histogram and the second histogram respectively to obtain the first flight time corresponding to the highest peak in the first histogram and the second flight time corresponding to the highest peak in the second histogram; The distance information of the target object is calculated based on the linear relationship between the first exposure period, the second exposure period, the first flight time, and the second flight time. The step of calculating the distance information of the target object based on the linear relationship between the first exposure period, the second exposure period, the first flight time, and the second flight time includes: Based on the first exposure period, the second exposure period, the first flight time, and the second flight time, a linear equation about the flight time is constructed, wherein the linear equation about the flight time is M1. period1 + T1 = M2 period2 +T2=T, where period1 is the first exposure period, period2 is the second exposure period, T1 is the first flight time, T2 is the second flight time, T is the flight time of the target object detected according to the original laser period, and M1 and M2 are positive integers; The values ​​of M1 and M2 are obtained by solving the linear equation of the flight time using a preset algorithm. The flight time of the target object is calculated based on the value of M1 or M2, and the distance information of the target object is calculated based on the flight time of the target object. 2.The storage space saving DTOF ranging method of claim 1, wherein, The step of performing peak-finding processing on the first and second histograms respectively to obtain the first flight time corresponding to the highest peak in the first histogram and the second flight time corresponding to the highest peak in the second histogram includes: Peak finding processing is performed on the first histogram to confirm the first time bin value corresponding to the highest peak in the first histogram; Peak finding processing is performed on the second histogram to confirm the second time bin value corresponding to the highest peak in the second histogram; Based on the time unit corresponding to each timebox in the current histogram, the first timebox value and the second timebox value are converted into the first flight time and the second flight time, respectively. 3.The storage space saving DTOF ranging method of claim 1, wherein, The preset algorithm is either the pilot method or the table lookup method. 4.The storage space saving DTOF ranging method of claim 1, wherein, The method also includes: The storage space for histogram statistics is configured based on the larger value between the first exposure period and the second exposure period.

5. The storage space saving DTOF ranging method of claim 4, wherein, The storage space for the histogram statistics is obtained using the following formula: memory = (period_max / bin_width) count_max Wherein, memory is the storage space of the histogram statistics, period_max is the larger value between the first exposure period and the second exposure period, bin_width is the time unit corresponding to each time bin in the histogram, and count_max is the number of bits corresponding to the largest photon count value in the histogram.

6. A DTOF ranging device that saves storage space, characterized by, include: The period decomposition module is used to decompose the original laser period into two coprime positive integers to obtain a first exposure period and a second exposure period, the product of the first exposure period and the second exposure period being equal to the original laser period. The exposure module is used to expose the target object in the first exposure cycle to obtain the first histogram; The target object is exposed during the second exposure cycle to obtain the second histogram; The data processing module is used to perform peak finding processing on the first histogram and the second histogram respectively to obtain the first flight time corresponding to the highest peak in the first histogram and the second flight time corresponding to the highest peak in the second histogram; and to calculate the distance information of the target object based on the linear relationship between the first exposure period, the second exposure period, the first flight time and the second flight time. The data processing module includes: An equation construction unit is used to construct an equation for flight time based on the first exposure period, the second exposure period, the first flight time, and the second flight time, wherein the equation for flight time is M1. period1 + T1 = M2 period2 +T2=T, where period1 is the first exposure period, period2 is the second exposure period, T1 is the first flight time, T2 is the second flight time, T is the flight time of the target object detected according to the original laser period, and M1 and M2 are positive integers; The solving unit is used to solve the linear equation of the flight time using a preset algorithm to obtain the values ​​of M1 and M2; The distance calculation unit is used to calculate the flight time of the target object based on the value of M1 or M2, and to calculate the distance information of the target object based on the flight time of the target object.

7. An electronic device, comprising: Includes the storage-saving DTOF ranging device as described in claim 6.

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