Distance measurement method and system of dTOF and electronic equipment

Abstract

The embodiment of the invention provides a dTOF ranging method and system and electronic equipment, and is used for fitting a complete waveform signal by using a small number of discrete sampling points in a reflected laser signal and reducing ranging errors. The method comprises the following steps: controlling an emitter to emit a laser signal to a target object, and controlling a receiver to receive the laser signal reflected by the target object; the method comprises the following steps: generating a first histogram based on a received laser signal, and sampling waveforms in the first histogram to obtain N discrete points; obtaining a value with the maximum count value in the N discrete points, recording the value as a first peak value, and obtaining a first full width at half maximum of a waveform in the emitted laser signal; performing Gaussian waveform fitting on the N discrete points based on the first peak value and the first full width at half maximum, and outputting a second histogram; and extracting waveform feature information of the second histogram to obtain a second peak value and a second full width at half maximum, and calculating a compensation value.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of electromagnetic wave ranging, and in particular to a dTOF ranging method, system and electronic equipment. Background Art

[0002] As the number of pixels in the single photon avalanche detector (SPAD) array increases, the distance of measurement increases, the number of rectangular images in the histogram increases accordingly, and the amount of output data increases exponentially. For example, taking a 192x256 pixel, 672-bin histogram as an example, assuming that each bin is 12 bits, the amount of data output per frame is 396 Mb. If the expected frame rate is 10 fps, the interface rate of data transmission needs to meet 4 Gb / s. Such a large amount of data poses great challenges to the interface rate and back-end data processing capabilities.

[0003] The current mainstream SPAD array chips all have built-in digital signal processing (DSP). During the initial data processing of the original histogram, as the data is compressed in large quantities, the shape characteristics of the histogram will be lost. When faced with a target with a strong original echo signal, the back end cannot perform depth compensation, which causes signal pile-up under extremely strong original echo signals and ultimately leads to inaccurate measurements. Summary of the invention

[0004] The embodiments of the present application provide a dTOF ranging method, system and electronic device for fitting a complete waveform signal using a small number of discrete sampling points in a reflected laser signal to reduce ranging errors.

[0005] A first aspect of an embodiment of the present application provides a dTOF ranging method, including:

[0006] Controlling the transmitter to transmit a laser signal to a target object, and controlling the receiver to receive the laser signal reflected by the target object;

[0007] Based on the received laser signal, a first histogram is generated, and a waveform in the first histogram is sampled to obtain N discrete points;

[0008] Obtaining the maximum count value among the N discrete points, recording it as a first peak value, and obtaining a first half-width of a waveform in the emitted laser signal;

[0009] Based on the first peak value and the first half-width, performing Gaussian waveform fitting on the N discrete points, and outputting a second histogram;

[0010] The waveform feature information of the second histogram is extracted to obtain a second peak value and a second half-height width, and a compensation value is calculated.

[0011] Optionally, the extracting of waveform feature information of the second histogram to obtain a second peak value and a second half-width, and calculating a compensation value further includes:

[0012] Obtaining an initial depth value based on the second histogram;

[0013] The measured distance of the target object is calculated according to the initial depth value and the compensation value.

[0014] Optionally, the extracting of waveform feature information of the second histogram to obtain a second peak value and a second half-width, and calculating a compensation value further includes:

[0015] Obtaining an initial depth value based on the value with the largest count value among the N discrete points;

[0016] The measured distance of the target object is calculated according to the initial depth value and the compensation value.

[0017] Optionally, performing Gaussian waveform fitting on the N discrete points based on the first peak value and the first half-width to output a second histogram includes:

[0018] The first peak value and the first half-width are input into a Gaussian waveform fitting formula to perform Gaussian waveform fitting to obtain the second histogram; wherein the Gaussian waveform fitting formula is: Amp is the first peak value; σ is the first half-width; μ is 0; GaussFitting is the photon count value after Gaussian waveform fitting; and x is a time bin.

[0019] Optionally, the extracting waveform feature information of the second histogram, obtaining a second peak value and a second half-width, and calculating a compensation value further includes:

[0020] The second peak value and the second half-height width are input into the error calculation formula; wherein the error calculation formula is:

[0021] Wherein, the f(FWHM,Height) is used to represent the error value, and the p n ,g n is the coefficient, n is the order of the polynomial, the FWHM is the second half-width, and the Height is the second peak value.

[0022] A second aspect of an embodiment of the present application provides a dTOF ranging system, including:

[0023] A transmitter, used for transmitting a laser signal to a target object;

[0024] a receiver, configured to receive the laser signal reflected by the target object;

[0025] The controller is used to generate a first histogram based on the received laser signal, sample the waveform in the first histogram to obtain N discrete points; obtain the value with the largest count value in the N discrete points, record it as the first peak value, and obtain the first half-width of the waveform in the emitted laser signal; based on the first peak value and the first half-width, perform Gaussian waveform fitting on the N discrete points and output a second histogram; extract the waveform feature information of the second histogram to obtain the second peak value and the second half-width, and calculate the compensation value.

[0026] Optionally, the number of SPADs included in the receiver exceeds a predetermined value.

[0027] Optionally, the waveform in the first histogram and the waveform in the second histogram have the same feature information, and the feature information includes a peak value and a half-height width.

[0028] Optionally, the controller is further configured to obtain an initial depth value based on the second histogram, so as to calculate a measured distance of the target object according to the compensation value.

[0029] A third aspect of an embodiment of the present application provides an electronic device, comprising the dTOF ranging system described in the second aspect.

[0030] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages: through a dTOF ranging method disclosed in the embodiments of the present application, the received laser signal can be used to extract a small number of discrete points from the complete histogram data to reduce the amount of data for easy transmission, and then the complete histogram waveform signal can be fitted using Gaussian, and the depth compensation value can be calculated using the waveform signal, thereby improving the ranging accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0032] Figure 1a This is a diagram showing a change in working state of an existing SPAD;

[0033] Figure 1b A schematic diagram of a histogram and a laser waveform under an existing weak signal;

[0034] Figure 1c It is a schematic diagram of collecting a histogram under an existing strong signal;

[0035] Figure 2 It is a schematic diagram of an existing DSP data processing;

[0036] Figure 3 A schematic diagram of a flow chart of a dTOF ranging method disclosed in an embodiment of the present application;

[0037] Figure 4 A schematic flow chart of another dTOF ranging method disclosed in an embodiment of the present application;

[0038] Figure 5 A schematic diagram of a laser waveform disclosed in an embodiment of the present application;

[0039] Figure 6 A schematic diagram of an echo shape fitted based on sampling points disclosed in an embodiment of the present application;

[0040] Figure 7 A comparison diagram of ranging errors before and after correction disclosed in an embodiment of the present application;

[0041] Figure 8 A schematic diagram of the structure of a dTOF ranging system disclosed in an embodiment of the present application;

[0042] Fig. 9 A schematic diagram of the structure of a dTOF electronic device disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0043] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0044] It should be noted that the descriptions involving "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0045] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0046] The direct time-of-flight (dTOF) ranging system based on SPAD has the characteristics of being resistant to sunlight and interference. Specifically, SPAD can be divided into three states during the entire working process. For details, please refer to Figure 1a , Figure 1a This is a diagram showing the change in working state of an existing SPAD (the horizontal axis is time, and the vertical axis is voltage).

[0047] 1. Avalanching: The SPAD device receives photons, triggers an avalanche, and generates a negative pressure.

[0048] 2. Quenching: After avalanche occurs in the SPAD device, in order to avoid the voltage increasing without limit and burning the device, active or passive methods are used to suppress the avalanche and stop the circuit from working.

[0049] 3. Resetting (recharging), pulling the SPAD device back to the state before the photon trigger, waiting for the next trigger.

[0050] It can be seen that there is a recovery time after the avalanche when the SPAD can detect the next photon, which is the dead time. When the echo signal is weak, the photons will not arrive continuously in a short time (dead time). Then, in the time-photon number statistical histogram formed during the measurement, the shape of the signal peak is close to the laser emission waveform, as shown in Figure 1. Figure 1b , Figure 1bThe following is a schematic diagram of a histogram and laser waveform under an existing weak signal. However, as the signal gradually increases, due to the arrival of a large number of photons in a short period of time, Figure 1c , Figure 1c FIG. 1 is a schematic diagram of an existing histogram acquisition under a strong signal. Figure 1c In the process, the SPAD is triggered in advance and has no detection capability after entering the dead time, which eventually causes the signal peak in the histogram to move forward, resulting in inaccurate ranging.

[0051] Although the current mainstream SPAD array chips have built-in DSP modules, preliminary data processing of the original histogram can be performed. Figure 2 , Figure 2 The following is a schematic diagram of an existing DSP data processing. The on-chip DSP will locate the location of the signal echo through the peak-finding module. In order to further compress the output data, a point sampling is performed on the basis of the signal echo, and the entire echo data is converted into several sampling points, which are then output to the back-end data processing module for depth calibration and point cloud generation. For example, assuming that the chip supports 5-echo peak-finding function, each echo has 5 sampling points, and each sampling point has a bit width of 12 bits, then each frame of data is 480 bits, which is only one millionth of the original histogram. However, the large amount of data compression also causes the shape characteristics of the histogram to be lost. When facing a target with a strong echo signal, the back-end cannot perform depth compensation.

[0052] To solve the technical problems mentioned above, please refer to Figure 3 , Figure 3 The flowchart of a dTOF ranging method disclosed in an embodiment of the present application includes steps 301 to 305.

[0053] 301. Control a transmitter to transmit a laser signal to a target object, and control a receiver to receive the laser signal reflected by the target object.

[0054] In view of the various problems mentioned above, it is necessary to adjust the laser signal. Therefore, in one of the feasible solutions, in order to facilitate understanding of the waveform of the emitted laser signal, please refer to Figure 5 , Figure 5 FIG. 1 is a schematic diagram of a laser waveform disclosed in an embodiment of the present application. Figure 5It can be seen that the ideal laser waveform is a triangular wave, and the increase in energy and the laser's luminous time increase linearly. However, in actual scenarios, the waveform of the laser is closer to a Gaussian waveform, that is, the energy of the laser will rise slowly and non-linearly. Based on this feature, the characteristics of the Gaussian waveform can be used to fit the collected signal. Specifically, this embodiment proposes a ranging system, which includes a transmitter, a receiver, and a controller. The above-mentioned transmitter, receiver, and controller will be described separately later, and will not be repeated here. Among them, the number of SPADs included in the receiver exceeds a predetermined value.

[0055] Specifically, the ranging system first controls the transmitter to transmit a laser signal to the target object. Thus, after the laser signal reaches the target object, it will reflect the laser signal. Then, the ranging system needs to control the receiver to receive the laser signal reflected by the target object.

[0056] In one of the specific embodiments, the signal strength of the transmitter when emitting the laser signal should also be controlled.

[0057] 302. Generate a first histogram based on the received laser signal, and sample the waveform in the first histogram to obtain N discrete points.

[0058] After the ranging system receives the reflected laser signal, the controller can generate a first histogram based on the received laser signal, thereby sampling and detecting the waveform in the first histogram to obtain N discrete points.

[0059] In one specific embodiment, the controller calculates the distance by measuring the round trip time of the laser pulse, and analyzes the reflection characteristics of the surface of the target object by the signal intensity of the reflected laser signal. Furthermore, before generating the histogram, a filtering algorithm (such as Gaussian filtering or median filtering, etc.) can also be used to remove noise. Then the signal intensity or distance value is normalized to the range of the feature (such as 0-255). If the laser signal at this time contains multiple reflection peaks, the laser signal needs to be processed in segments. Then, the distribution of different distance values ​​or the distribution of reflected signal intensity is statistically analyzed to generate the first histogram. Then, the waveform in the first histogram is randomly sampled (points can be selected densely at the peak of the wave crest and sparsely at the edge of the wave), so as to obtain N discrete points. It can also be understood that each discrete point corresponds to a time box, and each time box corresponds to the number of photons.

[0060] 303. Obtain the maximum count value among the N discrete points, record it as the first peak value, and obtain the first half-height width of the waveform in the emitted laser signal.

[0061] Based on step 302, the controller compares and filters out the value with the largest count value among the N discrete points, and at the same time, records the value as the first peak value. Furthermore, the controller also needs to obtain the first half-width of the waveform of the laser signal when the transmitter is transmitting. It should be noted that the half-width is usually used to describe the width of a signal, waveform or distribution. It represents the width at half the height of the peak. Specifically, first find the maximum value (peak value) of the waveform of the emitted laser signal. Then draw a horizontal line at half the height of the peak. Calculate the distance between the two points where this horizontal line intersects the curve, which is the half-width, which is the difference between the two time boxes.

[0062] In one specific embodiment, in the reflected laser signal, the maximum value (first peak value) of the N discrete points in the first histogram generated by the reflected laser signal is calculated. In the emitted laser signal, the half-height width (FWHM, Full Width Half Maximum) of the waveform in the emitted laser signal is determined.

[0063] 304. Perform Gaussian waveform fitting on the N discrete points based on the first peak value and the first half-width, and output a second histogram.

[0064] Then, Gaussian waveform fitting can be performed on the N discrete points using the first peak value and the first half-width, thereby outputting a second histogram.

[0065] In one specific embodiment, since the waveform of the control laser has the characteristics of a Gaussian waveform, N discrete points are fitted through the waveform characteristics of the first peak value and the first half-height width in the laser signal, so that the shape information such as the height or width of another signal peak is obtained through the waveform fitting result, and then the second histogram is fitted. It should be noted that the waveform in the first histogram and the waveform in the second histogram have the same characteristic information, and the characteristic information includes the peak value and the half-height width.

[0066] 305. Extract waveform feature information of the second histogram, obtain a second peak value and a second half-width, and calculate a compensation value.

[0067] Therefore, after the second histogram is obtained by Gaussian fitting, it is necessary to extract the waveform feature information in the second histogram, so as to obtain the second peak value and the second half-height width of the second histogram, and calculate the compensation value through the second peak value and the second half-height width. It should be noted that the compensation value is used to improve the ranging accuracy.

[0068] Furthermore, the second peak value is understood to be the peak in the waveform of the corresponding second histogram, and the corresponding second half-height width is the distance between two points at half the height of the peak value. The specific acquisition method has been described in the above steps and will not be repeated here.

[0069] In one specific embodiment, by extracting the waveform features of the second histogram, more accurate width and height data, as well as the peak data of the second histogram, can be obtained, and the position of the corresponding time bin can be further determined, which will be described in detail later. Then, the compensation value (also understood as the error value) corresponding to the laser signal can be determined by the second peak value and the second half-height width.

[0070] A dTOF ranging method disclosed in this embodiment can utilize the received laser signal to extract a small number of discrete points from the complete histogram data to reduce the amount of data for easy transmission, and then use Gaussian fitting to obtain a complete histogram waveform signal, and use the waveform signal to calculate the depth compensation value, thereby improving the ranging accuracy.

[0071] See also Figure 4 , Figure 4 This is a flow chart of another dTOF ranging method disclosed in an embodiment of the present application, including steps 401 to 404.

[0072] 401. Input the first peak value and the first half-width into a Gaussian waveform fitting formula to perform Gaussian waveform fitting to obtain a second histogram.

[0073] In this embodiment, step 401 is the same as the aforementioned Figure 3 Specifically, the first peak value and the first half-width can be input into the Gaussian waveform fitting formula to perform Gaussian waveform fitting, thereby obtaining the second histogram. It should be noted that the Gaussian waveform fitting formula is: Amp is the first peak value, that is, the number of photons corresponding to the peak-to-peak value of the signal in the first histogram; σ is the first half-width, that is, the standard deviation (the half-width under the waveform configuration of the corresponding emitted laser signal); μ is the mean; GaussFitting is the photon count value after Gaussian waveform fitting; x is the time bin. Furthermore, since μ is the deviation value relative to the 0 point, it can be considered as the location of the signal peak (bin index). However, in the current fitting scheme, only the shape information such as the height and width of the signal peak needs to be obtained through the fitting results. Therefore, in order to simplify the calculation, μ can be considered as 0.

[0074] 402. Input the second peak value and the second half-width into an error calculation formula to obtain an error value.

[0075] In this embodiment, step 402 is similar to the above Figure 3 The step 305 in FIG. 3 is similar. Specifically, by analyzing the second histogram, the second peak value and the second half-height width are obtained. Then, the second peak value and the second half-height width are input into the error calculation formula to obtain the error value. It should be noted that the error calculation formula is:

[0076]

[0077] Among them, f(FWHM,Height) is used to represent the error value, p n ,g n is the coefficient, n is the order of the polynomial, FWHM is the second half-width, and Height is the second peak value, that is, the peak-to-peak value of the signal. Generally speaking, the larger n is, the more accurate the calculation of f(FWHM, Height), but in this embodiment, n=3 is sufficient. Specifically, in the laboratory and production line, based on multiple modules and multiple pixels, histograms and ranging errors can be collected at different known distances (GT, Ground Truth), and the fitting relationship f(FWHM, Height) between the waveform characteristics (FHWM and Height) and the ranging error can be obtained, so that in actual use, the corresponding compensation value, that is, the error value, can be calculated.

[0078] Further, for easier understanding, please refer to Figure 6 , Figure 6 This is a schematic diagram of an echo shape fitted based on sampling points disclosed in an embodiment of the present application. Figure 6 The effect of Gaussian fitting based on a few points is shown. The fitting effectively restores the waveform of the echo. If the half-height width (bin index corresponding to half the peak height) is calculated based on the data of a few sampling points, only bin 5 and bin 7 that meet the conditions can be found. The half-height width corresponding to (time bin) is 3bin, so there is a significant error. If based on the fitting waveform, the accurate decimal part can be calculated, thereby reducing the error in calculating the half-height width.

[0079] Thus, the measured distance of the target object can be obtained in different ways, that is, step 403 or step 404 is executed.

[0080] 403. Based on the maximum count value among the N discrete points, an initial depth value is obtained, and the measurement distance of the target object is calculated according to the initial depth value and the compensation value.

[0081] In one of the feasible technical solutions, the initial depth value can be obtained by calculating the maximum count value among N discrete points. Then, the measured distance of the target object is calculated based on the initial depth value and the compensation value.

[0082] In one specific embodiment, the distance value corresponding to the maximum count value among the N discrete points, that is, the maximum photon number, is considered as the initial depth value. Then, the initial depth value is subtracted from the compensation value to calculate the measured distance of the target object.

[0083] 404. Obtain an initial depth value based on the second histogram, and calculate a measured distance of the target object according to the initial depth value and the compensation value.

[0084] In one feasible technical solution, the initial depth value can be directly obtained through the second histogram, so as to calculate the measured distance of the target object according to the initial depth value and the compensation value.

[0085] In one specific embodiment, by analyzing the distribution in the second histogram, the peak or valley features (including the peak and half-height width) are identified. Furthermore, the initial depth value can be obtained by calculating the quantiles (such as the median, quartiles, etc.) in the second histogram, wherein the mode (highest peak) of the histogram corresponds to the depth value with the highest frequency in the data. Then, the measured distance of the target object is calculated by subtracting the initial depth value from the compensation value.

[0086] In conjunction with step 403 or step 404, please refer to Figure 7 , Figure 7 This is a comparison diagram of ranging errors before and after correction disclosed in an embodiment of the present application. Figure 7 The ranging error of 200 pixels based on this solution is demonstrated. Before correction, the ranging error exceeded 60cm. After correction, the ranging error of most pixels is less than ±5cm, which greatly improves the ranging accuracy.

[0087] Through a dTOF ranging method disclosed in this embodiment, fitting (Gaussian fitting) is performed based on the characteristics of the laser waveform under limited sampling points to restore the original signal waveform. At the same time, under the fitted waveform characteristics, the uncertainty correction under strong echo is performed to improve the ranging accuracy.

[0088] It should be understood that, although the various steps in the flowcharts involved in the various embodiments described above are displayed in sequence according to the indications of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless there is a clear description in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments described above may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of the steps or stages in other steps.

[0089] See below Figure 8 , Figure 8 A schematic diagram of the structure of a dTOF ranging system disclosed in an embodiment of the present application.

[0090] The dTOF ranging system 800 includes a transmitter 801 , a receiver 803 and a controller 804 .

[0091] The transmitter 801 is used to transmit a laser signal to the target object 802; the receiver 803 is used to receive the laser signal reflected by the target object 802; the controller 804 is used to generate a first histogram based on the received laser signal, sample the waveform in the first histogram, and obtain N discrete points; obtain the value with the largest count value among the N discrete points, record it as the first peak value, and obtain the first half-width of the waveform in the emitted laser signal; based on the first peak value and the first half-width, perform Gaussian waveform fitting on the N discrete points, and output a second histogram; extract the waveform feature information of the second histogram, obtain the second peak value and the second half-width, and calculate the compensation value.

[0092] Further, the number of SPADs included in the receiver 803 exceeds a predetermined value.

[0093] Furthermore, the waveform in the first histogram and the waveform in the second histogram have the same feature information, and the feature information includes a peak value and a half-height width.

[0094] Furthermore, the controller 804 is further configured to obtain an initial depth value based on the second histogram, so as to calculate a measured distance of the target object 802 according to the compensation value.

[0095] The dTOF ranging system in the embodiment of the present application is used to perform the above Figure 2 or Figure 3 The dTOF ranging method in the illustrated embodiment.

[0096] See below Fig. 9 , a schematic diagram of the structure of a dTOF electronic device disclosed in an embodiment of the present application includes:

[0097] CPU 901, memory 905, input / output interface 904, wired or wireless network interface 903 and power supply 902;

[0098] The memory 905 is a temporary storage memory or a permanent storage memory;

[0099] The CPU 901 is configured to communicate with the memory 905 and execute the instructions in the memory 905 to perform the aforementioned Figure 2 or Figure 3 The dTOF ranging method in the embodiment shown, or, Figure 8 The dTOF ranging system in the illustrated embodiment.

[0100] The embodiment of the present application also provides a chip system, the chip system includes at least one processor and a communication interface, the communication interface and the at least one processor are interconnected through a line, and the at least one processor is used to run a computer program or instruction to execute the aforementioned Figure 2 or Figure 3 The dTOF ranging method in the embodiment shown, or, Figure 8 The dTOF ranging system in the illustrated embodiment.

[0101] The embodiment of the present application also provides a computer-readable storage medium, the computer-readable storage medium includes instructions, when the instructions are executed on a computer, the computer executes the aforementioned Figure 2 or Figure 3 The dTOF ranging method in the embodiment shown, or, Figure 8 The dTOF ranging system in the illustrated embodiment.

[0102] The present application also provides a computer program product including instructions, which, when executed on a computer, enables the computer to execute the aforementioned Figure 2 or Figure 3 The dTOF ranging method in the embodiment shown, or, Figure 8 The dTOF ranging system in the illustrated embodiment.

[0103] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0104] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0105] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0106] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0107] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, read-only memory), random access memory (RAM, random access memory), disk or optical disk and other media that can store program code.

Claims

1. A dTOF ranging method, characterized in that: The method comprises: Controlling the transmitter to transmit a laser signal to a target object, and controlling the receiver to receive the laser signal reflected by the target object; Based on the received laser signal, a first histogram is generated, and a waveform in the first histogram is sampled to obtain N discrete points; Obtaining the maximum count value among the N discrete points, recording it as a first peak value, and obtaining a first half-width of a waveform in the emitted laser signal; Based on the first peak value and the first half-width, performing Gaussian waveform fitting on the N discrete points, and outputting a second histogram; The waveform feature information of the second histogram is extracted to obtain a second peak value and a second half-height width, and a compensation value is calculated.

2. The dTOF ranging method according to claim 1, characterized in that: The step of extracting waveform feature information of the second histogram, obtaining a second peak value and a second half-height width, and calculating a compensation value further includes: Obtaining an initial depth value based on the second histogram; The measured distance of the target object is calculated according to the initial depth value and the compensation value.

3. The dTOF ranging method according to claim 1, characterized in that: The step of extracting waveform feature information of the second histogram, obtaining a second peak value and a second half-height width, and calculating a compensation value further includes: Obtaining an initial depth value based on the value with the largest count value among the N discrete points; The measured distance of the target object is calculated according to the initial depth value and the compensation value.

4. The dTOF ranging method according to claim 1, characterized in that: The step of performing Gaussian waveform fitting on the N discrete points based on the first peak value and the first half-width to output a second histogram includes: The first peak value and the first half-width are input into a Gaussian waveform fitting formula to perform Gaussian waveform fitting to obtain the second histogram; wherein the Gaussian waveform fitting formula is: Amp is the first peak value; σ is the first half-width; μ is 0; GaussFitting is the photon count value after Gaussian waveform fitting; and x is a time bin.

5. The dTOF ranging method according to claim 1, characterized in that: The step of extracting waveform feature information of the second histogram, obtaining a second peak value and a second half-height width, and calculating a compensation value further includes: The second peak value and the second half-height width are input into the error calculation formula; wherein the error calculation formula is: Wherein, the f(FWHM,Height) is used to represent the error value, and the p n ,g n is the coefficient, n is the order of the polynomial, the FWHM is the second half-width, and the Height is the second peak value.

6. A dTOF ranging system, characterized in that: The system comprises: A transmitter, used for transmitting a laser signal to a target object; a receiver, configured to receive the laser signal reflected by the target object; The controller is used to generate a first histogram based on the received laser signal, sample the waveform in the first histogram to obtain N discrete points; obtain the value with the largest count value in the N discrete points, record it as the first peak value, and obtain the first half-width of the waveform in the emitted laser signal; based on the first peak value and the first half-width, perform Gaussian waveform fitting on the N discrete points and output a second histogram; extract the waveform feature information of the second histogram to obtain the second peak value and the second half-width, and calculate the compensation value.

7. The distance measurement system according to claim 6, characterized in that: The receiver includes a number of SPADs exceeding a predetermined value.

8. The distance measurement system according to claim 6, characterized in that: The waveform in the first histogram and the waveform in the second histogram have the same feature information, and the feature information includes a peak value and a half-height width.

9. The distance measurement system according to claim 6, characterized in that: The controller is further configured to obtain an initial depth value based on the second histogram, so as to calculate a measured distance of the target object according to the compensation value.

10. An electronic device, characterized in that: Comprising a ranging system as claimed in any one of claims 6 to 9.

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