A time-of-flight based distance detection method and system

Abstract

The application provides a time-of-flight-based distance detection method and system, wherein the method comprises: emitting a detection light beam, at least part of the detection light beam being transmitted to a target through a lens; adjusting an opening area of a pixel array according to a detection mode, the opening area comprising at least one opening pixel; receiving reflected light reflected by the target back by the opening pixel; and processing the reflected light according to different detection modes to calculate the distance of the target. The opening area adjustment and reflected light processing under different detection modes can eliminate the distance detection interference under different detection modes and improve the distance measurement accuracy and signal-to-noise ratio.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of distance detection technology, and in particular to a distance detection method and system based on time of flight. BACKGROUND

[0002] Currently, time of flight (TOF) technology is commonly used in the field of distance measurement to achieve distance detection. Time of flight technology is a technology that uses the time difference between the flight of light at the transmitting end and the reflection of light by a target object to the receiving end to calculate the distance of the target object. It is widely used in fields such as three-dimensional modeling, portable electronic devices, AR / VR, drones, and self-driving cars.

[0003] In a distance sensor based on time of flight, the transmitting end and the receiving end generally include a lens. When the target object is far away, at least part of the light reflected back to the receiving end by the target object is relatively weak. At this time, at least part of the light reflected back by the lens is relatively strong. In this way, the light reflected back by the lens accounts for a large part of the data bandwidth of the subsequent data processing circuit, making it difficult for the light reflected back by the target object to be captured by the pixel unit. When performing histogram statistics of the distance, the distance of the lens is mistaken for the distance of the target object because the light intensity corresponding to the distance of the lens is the strongest and the histogram is the highest. Ultimately, this can lead to errors in distance measurement. Moreover, there will be light emitted from the lens during the entire distance measurement process, thereby reducing the signal-to-noise ratio of the distance measurement signal. When performing distance detection, part of the emitted light is reflected back to the receiving end by the lens. This causes the light reflected back by the lens to interfere with the light reflected back by the target object, regardless of the distance of the target object, which can lead to errors in distance measurement and reduce the signal-to-noise ratio of the distance measurement signal. SUMMARY

[0004] In view of the deficiencies of the prior art described above, the purpose of the present application is to provide a distance detection method and system based on time of flight to eliminate distance detection interference in different detection modes and improve the accuracy and signal-to-noise ratio of distance measurement.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] The present application provides a distance detection method based on time of flight, comprising the following steps:

[0007] Emitting a detection light beam, at least part of the detection light beam transmits through the lens and is emitted towards the target;

[0008] Adjusting the opening area of the pixel array according to the detection mode, the opening area comprising at least one opening pixel;

[0009] Receiving reflected light reflected by the target by the opening pixel;

[0010] According to the different detection modes, the reflected light is processed to calculate the distance of the target.

[0011] In one embodiment, when in the non-close distance detection mode, the adjusting the opening area of the pixel array according to the detection mode comprises:

[0012] Controlling all pixels in the pixel array to be turned on.

[0013] In one embodiment, when in the non-close distance detection mode, the processing the reflected light according to the different detection modes to calculate the distance of the target comprises:

[0014] Converting the reflected light to obtain trigger time data;

[0015] Removing close distance data from the trigger time data, the close distance data being trigger time data corresponding to a distance less than a preset distance;

[0016] Constructing a first histogram according to the removed trigger time data;

[0017] According to the first histogram, obtaining a time of flight corresponding to a highest peak, and calculating the distance of the target according to the time of flight.

[0018] In one embodiment, when in the close distance detection mode, the adjusting the opening area of the pixel array according to the detection mode comprises:

[0019] Controlling part of the pixels in the pixel array to be turned on to form the opening area.

[0020] In one embodiment, when in the close distance detection mode, the processing the reflected light according to the different detection modes to calculate the distance of the target comprises:

[0021] Converting the reflected light to obtain trigger time data;

[0022] Obtaining lens parameters, and removing the lens parameters to obtain a second histogram, the lens parameters being trigger time data corresponding to a distance of the lens;

[0023] According to the second histogram, obtaining a time of flight corresponding to a highest peak, and calculating the distance of the target according to the time of flight.

[0024] In one embodiment, before the obtaining the lens parameters, the method further comprises:

[0025] The ID numbers of the pixel units in the opening region are set to the same value, and the data sensed by the pixel units are all counted into the same histogram unit.

[0026] In one embodiment, the flight time corresponding to the highest peak is obtained according to the second histogram, and the distance of the target is calculated according to the flight time.

[0027] The pulse width of the highest peak of the second histogram is compared with the pulse width of the emitted pulse, and if they are inconsistent, the highest peak is removed, and then the second highest peak is found until the peak meets the pulse width of the emitted pulse and is taken as a matching peak.

[0028] The flight time corresponding to the matching peak is obtained, and the distance of the target is calculated according to the flight time.

[0029] In one embodiment, the shape of the opening region is the same as that of the lens, and the offset angle between the center of the opening region and the center of the lens is less than a preset angle.

[0030] In one embodiment, the number of pixel units in the opening region is 1-10.

[0031] The second aspect of the present application provides a distance detection system based on flight time, comprising:

[0032] A transmitting module is configured to emit a detection light beam, and at least part of the detection light beam is transmitted to a target through a lens.

[0033] A receiving module comprises a pixel array and is configured to receive reflected light reflected by the target.

[0034] A control module is configured to control the transmitting module to emit the detection light beam, adjust an opening region of the pixel array according to a detection mode, and process the reflected light according to different detection modes to calculate the distance of the target.

[0035] The opening region comprises at least one opening pixel.

[0036] The present application has the following advantages: a distance detection method and system based on flight time are provided, the opening region of the pixel array is adjusted under different detection modes, and the received reflected light is processed accordingly, so as to eliminate the distance detection interference under different detection modes and improve the accuracy and signal-to-noise ratio of distance measurement. BRIEF DESCRIPTION OF DRAWINGS

[0037] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0038] Figure 1Structure diagram of a time-of-flight based distance detection system in an embodiment of the present application;

[0039] Figure 2 Flow chart of a time-of-flight based distance detection method in an embodiment of the present application;

[0040] Figure 3 Schematic diagram of an opening region in a pixel array in an embodiment of the present application;

[0041] Figure 4 Schematic diagram of an exemplary histogram statistics in an embodiment of the present application. DETAILED DESCRIPTION

[0042] In order to make the technical problems to be solved by the embodiments of the present application, technical solutions and beneficial effects clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not intended to limit the present application.

[0043] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, the connection can be for fixing or for circuit communication.

[0044] It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the embodiments of the present application and simplify the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0045] In addition, the terms "first", "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0046] Please refer to Figure 1 , Figure 1Fig. 1 is a schematic diagram of a time-of-flight based distance detection system according to an embodiment of the present application, the distance detection system comprising a control module 11, a transmitting module 12 and a receiving module 13, the control module 11 being connected to the transmitting module 12 and the receiving module 13, wherein the transmitting module 12 is configured to transmit a probe light beam, at least a portion of the probe light beam being transmitted through a lens 10 towards a target 60, and at least a portion of the probe light beam being reflected by the target 60 to form a reflected light; the receiving module 13 comprising a pixel array 131 comprising a plurality of pixels, the receiving module 13 being configured to receive the reflected light reflected by the target 60; the control module 11 being configured to synchronously control the transmission and reception of the light, to dynamically control the switching area of the pixel array 131 according to a detection mode, and to calculate distance information corresponding to the time-of-flight difference between the transmission and reception of the light.

[0047] Specifically, the transmitting module 12 comprises a driver 121 and a light source 122, etc., the light source 122 can be a light emitting diode (LED), a laser diode (LD), an edge emitting laser (EEL), a vertical cavity surface emitting laser (VCSEL), etc., the light source 122 being configured to transmit a probe light beam under the driving control of the driver 121, at least a portion of the probe light beam (light beam 30) being transmitted through the lens 10 towards the target 60, the light beam 50 reflected by the target 60 being received by the receiving module 13, and at least a portion of the probe light beam being reflected by the lens 10 to form a light beam 40, the light beam 40 also being received by the receiving module 13, thereby causing interference to the distance detection.

[0048] The receiving module 13 comprises a pixel array 131 and a receiving optical element 132, etc., the receiving optical element 132 can be one or a combination of a lens, a microlens array, a mirror, etc., the receiving optical element 132 being configured to receive the reflected light and guide the reflected light to the pixel array 131, the pixel array 131 comprising a plurality of pixels for collecting photons, in an embodiment, the pixel array 131 comprises a plurality of single photon avalanche photodiodes (SPADs), the SPAD being configured to respond to an incident single photon and output a photon signal indicating the corresponding arrival time of the received photon at each SPAD, of course, in other embodiments, other photoelectric conversion devices such as avalanche photodiodes, photomultiplier tubes, silicon photomultiplier tubes, etc. can also be used.

[0049] In one embodiment, the control module 11 includes a TDC (Time-to-Digital Converter) readout circuit and a histogram circuit. The TDC readout circuit is used to process the photon signals output by each pixel in the pixel array 131 to determine the photon flight time. The histogram circuit performs time window (time bin) statistics based on the flight time. When the flight time falls into a certain time window, the stored value corresponding to that time window is incremented by "1". The corresponding histogram is constructed based on the time window statistics results.

[0050] Since the lens 10 is always in front of the transmitting module 12 and the receiving module 13, whether in close-range or long-range detection, the reflected light received by the pixel array 131 includes both the beam 50 reflected by the target 60 and the beam 40 reflected by the lens 10. This results in interference peaks in the constructed histogram, causing deviations when calculating the distance to the target 60 based on the flight time corresponding to the peak value in the histogram. This reduces the signal-to-noise ratio of the ranging signal. The following describes how to solve this problem by applying a method to this range detection system, so as to eliminate interference in the range detection system under different detection modes and improve the ranging accuracy.

[0051] like Figure 2 As shown, Figure 2 This is a flowchart of a distance detection method based on time-of-flight in one embodiment of the present invention. The method specifically includes the following steps:

[0052] S201. A probe beam is emitted, at least a portion of which is emitted toward the target through a lens.

[0053] The light source is driven by a driver to emit a detection beam, which can be visible light, infrared light, ultraviolet light, etc. In one embodiment, a laser light source is preferably used to emit discrete laser pulses at a certain frequency under the control of the driver. The low duty cycle laser pulses can be used in direct-time of flight (d-TOF) measurement, which has advantages such as low power consumption and strong anti-interference ability compared with indirect-time of flight (i-TOF). Based on the reflection and transmission characteristics of the lens, at least part of the detection beam will be emitted towards the target through the lens and reflected by the target, while at least part of the detection beam will be reflected by the lens, resulting in reflected light containing lens interference.

[0054] S202. Adjust the open area of ​​the pixel array according to the detection mode, wherein the open area includes at least one open pixel.

[0055] In this embodiment, the detection mode can be divided into near distance detection and non-near distance detection according to the distance measurement range, so as to adapt to different distance detection scenes, and the opening area of the pixel array is adjusted correspondingly in different detection modes, the opening area includes at least one opening pixel, that is, the opening and closing of each pixel in the pixel array is flexibly controlled in different detection modes, so as to realize the adjustment of resolution and hardware power consumption in different detection modes.

[0056] S203, receiving the reflected light reflected by the target by the opening pixel.

[0057] Based on the opening area in different detection modes, the pixel units in the opening area, that is, the opening pixels, receive the reflected light reflected by the target, and each opening pixel performs high-precision single-photon response on the incident photons to obtain the arrival time of the photons at different opening pixels, so as to provide accurate time response data for subsequent histogram statistics.

[0058] S204, processing the reflected light according to the different detection modes, and calculating the distance of the target.

[0059] In different detection modes, the reflected light received by the opening pixel is processed and the distance of the target is calculated, which flexibly adapts to the detection requirements and noise sources in near distance detection and far distance detection, so that no matter how far or near the target is, the noise including lens interference in the reflected light can be processed to eliminate the distance detection interference in different detection modes and improve the accuracy of distance measurement.

[0060] In one embodiment, when in the non-near distance detection mode, step S202 includes:

[0061] Controlling all pixels in the pixel array to be opened.

[0062] When the target is far away, the resolution requirement of the detection system is higher, and as many reflected photons as possible need to be received, so all pixels in the pixel array need to be controlled to be opened, so that complete data can be collected for subsequent processing, and the distance measurement resolution is improved.

[0063] In one embodiment, when in the non-near distance detection mode, step S204 includes:

[0064] Converting and processing the reflected light to obtain trigger time data;

[0065] Removing near distance data from the trigger time data, the near distance data being trigger time data corresponding to a distance less than a preset distance;

[0066] Constructing a first histogram according to the trigger time data after removal;

[0067] According to the first histogram, a time of flight corresponding to a highest peak is obtained, and a distance of the target is calculated according to the time of flight.

[0068] In the embodiment, when in the non-close-range detection mode, the resolution requirement is relatively high, and therefore the reflected light is received by all the pixels in the pixel array to present the contour of the target object. At this time, in order to eliminate the close-range interference including the lens, the close-range data including the lens data is shielded during the distance measurement of the target, that is, the data smaller than a predetermined distance is discarded, so as to improve the signal-to-noise ratio and reduce the close-range noise.

[0069] In a specific implementation, based on the response of each pixel unit in the pixel array to the reflected light, the trigger time data of the photons at different pixel units is obtained through a time-to-digital converter (TDC), that is, the time of flight of the photons received by different pixel units is obtained, and the distance data is calculated correspondingly. In order to eliminate the interference noise in the close-range, the close-range data corresponding to the trigger time data smaller than a preset distance is removed from the trigger time data. The specific preset distance can be flexibly set, for example, 10 cm, 15 cm, etc. The close-range data can be removed after the trigger time data is obtained, for example, after obtaining each trigger time data, it is judged whether the trigger time data is close-range data. If yes, the trigger time data is removed and the time bin where the trigger time data falls is not continued to be confirmed. Therefore, after the close-range data is removed, the subsequent close-range data does not participate in the construction of the first histogram, so that when the distance of the target is calculated according to the highest peak of the first histogram, the calculation result smaller than the preset distance does not appear. For example, when the preset distance is set to 10 cm, it indicates that the minimum detection distance of the detection system at this time is 10 cm, and there is no detection capability smaller than the distance. The trigger time data corresponding to 0-10 cm is removed during actual detection, so that in the non-close-range detection mode, the effect of eliminating the close-range interference including the lens interference is achieved.

[0070] In one embodiment, when in the close-range detection mode, step S202 includes:

[0071] The part of the pixels in the pixel array is controlled to be turned on to form the opening region.

[0072] When the distance of the close-range target needs to be detected, the detection mode needs to be switched at this time, that is, the non-close-range detection mode is switched to the close-range detection mode. For example, when the opening instruction input by the user is received, the close-range detection function is opened, and at this time, the detection mode is switched to the close-range detection mode. Since the target is close during the close-range detection, the resolution requirement of the detection system is low, and therefore the part of the pixels in the pixel array is controlled to be turned on to meet the distance measurement requirement and reduce the power consumption.

[0073] As shown in the figure, the pixel array 131 includes a plurality of pixel units 1311, when the close-range detection function is turned on, the pixel units in the control area 1312 are turned on, and the pixel units outside the area 1312 are all turned off, thereby forming an open area. Figure 3

[0074] It can be understood that the shape, size and position of the open area can be adjusted according to requirements. In an embodiment, the shape of the open area is the same as the shape of the lens, for example, when the lens is circular, the open area can be arranged in a circular array or a ring array, and when the lens is rectangular, the open area is arranged in a rectangular array, so as to better adapt to the shape of the lens to receive photons.

[0075] In an embodiment, the offset angle between the center of the open area and the center of the lens is less than a preset angle, that is, in order to ensure that the partially open pixel units can better receive photons in the close-range detection mode, the pixel units in the middle area of the pixel array corresponding to the center of the lens are preferably turned on, so as to avoid the case that the offset angle between the open area and the lens is too large, which leads to difficulty in effectively receiving photons and reduces the accuracy of close-range detection.

[0076] In an embodiment, the number of pixel units in the open area is 1-10, and the size of the open area can be adjusted according to the size of the actual lens. Taking a rectangular array as an example, the number of pixel units in the open area can be controlled to be 2x2 or 3x3, etc.

[0077] In an embodiment, when in the close-range detection mode, step S204 includes:

[0078] Converting the reflected light to obtain trigger time data;

[0079] Obtaining lens parameters and removing the lens parameters to obtain a second histogram, the lens parameters referring to the trigger time data corresponding to the distance of the lens;

[0080] According to the second histogram, obtaining the time of flight corresponding to the highest peak, and calculating the distance of the target according to the time of flight.

[0081] In this embodiment, when in the close-range detection mode, the resolution requirement is relatively low, so the reflected light is received by part of the pixel array. Since the target object is very close, the lens interference cannot be eliminated by removing the close-range data, so two distance information may be measured at the same time during measurement, one is the distance of the lens, and the other is the distance of the target object, that is, the histogram may have two peaks. Therefore, the embodiment needs to perform targeted denoising processing for lens interference.

[0082] ​In practice, based on the response of the pixel units in the open area (i.e., the open pixels) to reflected light, the trigger time data of photons at different open pixels is obtained through TDC conversion, that is, the flight time of photons received by different open pixels is obtained. The distance data can be calculated from the flight time. Since the distance of the lens (the distance between the lens and the light source) is relatively fixed and known, in order to eliminate the reflection interference caused by the lens, the lens parameters in the detection system are obtained. The lens parameters are removed from the trigger time data to construct a second histogram. The lens parameters are the trigger time data corresponding to the distance of the lens. That is, the lens parameters do not participate in the construction of the second histogram, so that the second histogram will not have time bin peaks corresponding to the distance of the lens. By filtering out the lens interference peaks, the distance of the target can be calculated based on the flight time corresponding to the highest peak in the second histogram. This achieves the function of close-range detection while eliminating the interference caused by the lens, and can accurately measure the distance of close-range targets.

[0083] In one embodiment, before obtaining the lens parameters, the method further includes:

[0084] The ID numbers of all pixel units in the open area are set to the same value, and the data sensed by the pixel units are all counted into the same histogram unit.

[0085] When performing histogram statistics, each pixel unit has an ID, and pixel units with different IDs have corresponding histogram units for histogram statistics, such as... Figure 4 As shown, for example, when there are 9 pixel units 41 with different IDs, after reading the ID and trigger time data corresponding to the pixel unit 41 through the TDC readout circuit 42, histogram statistics are performed through 9 different histogram units 43. Ultimately, 9 histograms need to be stored, occupying a significant amount of storage resources. Since close-range detection does not require high resolution, to save hardware resources and reduce the histogram storage circuit, in close-range detection mode, the ID numbers of the pixel units in the open area are all set to the same value. For example, ... Figure 4 All nine IDs in the array are set to 0. When the TDC readout circuit 42 reads the ID and trigger time data corresponding to the pixel unit 41, since all IDs are 0, the trigger time data generated by the photon received by the pixel unit 41 falls completely into the first histogram unit 43. That is, as long as each pixel unit in the open area has trigger time data, it will be fused and accumulated to form a histogram. At this time, the detection system only calculates a distance value and does not display the outline of the target object. While realizing close-range measurement, it effectively saves hardware resource consumption and also reduces power consumption.

[0086] In the implementation, since only distance value is given in the close-range detection, when the detection system cooperates with the external master control chip, if the master control chip analyzes the distance data of the detector and finds that there is an object at the close range, the master control chip can output a switching prompt to prompt the user that the detector is too close to the target object and cannot display the contour of the object, and the detection needs to be performed at least at a certain distance, so that the user can adjust the distance between the detector and the target object or enable the close-range focusing function.

[0087] In one embodiment, according to the second histogram, a time of flight corresponding to the highest peak is obtained, and a distance of the target is calculated according to the time of flight, specifically including:

[0088] The pulse width of the highest peak of the second histogram is compared with the pulse width of the emitted pulse; if they are inconsistent, the highest peak is removed, and then the second highest peak is found until the peak meets the pulse width of the emitted pulse and is taken as a matching peak;

[0089] A time of flight corresponding to the matching peak is obtained, and a distance of the target is calculated according to the time of flight.

[0090] In the embodiment, after the second histogram is constructed based on the lens interference data removed, the distance is calculated by finding the highest peak matching the emitted pulse in the second histogram. Since the waveform of the received reflected light is basically similar to the waveform of the emitted pulse, to improve the accuracy of peak finding, the pulse width of the highest peak of the second histogram is compared with the pulse width of the emitted pulse. If they are inconsistent, the highest peak is identified as an invalid peak, and the second highest peak is continuously found for pulse width comparison. The pulse widths are sequentially found and matched until the matching peak with the pulse width of the emitted pulse is found. The distance of the target is calculated according to the time of flight corresponding to the matching peak. The reflected light of other interference objects at the close range is avoided from being captured. If the reflected light of the interference object is stronger than the reflected light of the target, the distance calculated according to the highest peak may not be the distance of the target. Therefore, the matching peak finding method ensures the accuracy of the peak used for distance calculation, and improves the accuracy and reliability of distance measurement.

[0091] It should be noted that the above steps do not necessarily have a certain sequence. Those skilled in the art can understand that the above steps can have different execution sequences in different embodiments according to the description of the embodiments of the present application, that is, they can be executed in parallel, or they can be exchanged and executed, and so on.

[0092] In summary, the application discloses a time-of-flight-based distance detection method and system, wherein the method comprises: emitting a detection light beam, at least part of the detection light beam being transmitted to a target through a lens; adjusting an opening area of a pixel array according to a detection mode, the opening area comprising at least one opening pixel; receiving reflected light reflected by the target by the opening pixel; and processing the reflected light according to different detection modes to calculate the distance of the target. The opening area adjustment and reflected light processing in different detection modes can eliminate the distance detection interference in different detection modes, and improve the distance measurement accuracy and signal-to-noise ratio.

[0093] The above is a further detailed description of the application in combination with specific preferred embodiments, and the specific implementation of the application cannot be limited to these descriptions. For those skilled in the art to which the application belongs, without departing from the concept of the application, a number of equivalent substitutions or obvious modifications can be made, and the performance or use is the same, which should be regarded as belonging to the protection scope of the application.

Claims

1. A time-of-flight based distance detection method, characterized in that, The method comprises the following steps: a probe light beam is emitted, at least part of the probe light beam transmits through a lens and is emitted to a target; an opening region of a pixel array is adjusted according to a detection mode, the opening region comprises at least one opening pixel; when in a non-close-range detection mode, all the pixels in the pixel array are controlled to be opened; when in a close-range detection mode, part of the pixels in the pixel array are controlled to be opened, forming the opening region; reflected light reflected by the target is received by the opening pixel; the reflected light is processed according to the detection mode, and the distance of the target is calculated; when in the non-close-range detection mode, close-range interference including the lens is eliminated; when in the close-range detection mode, reflection interference caused by the lens is eliminated.

2. The time-of-flight based distance detection method according to claim 1, characterized in that, When in the non-close-range detection mode, the processing of the reflected light according to the detection mode and the calculation of the distance of the target comprise: conversion processing is performed on the reflected light to obtain trigger time data; close-range data corresponding to trigger time data smaller than a preset distance is removed from the trigger time data; a first histogram is constructed according to the trigger time data after removal; a time of flight corresponding to a highest peak is obtained according to the first histogram, and the distance of the target is calculated according to the time of flight.

3. The time-of-flight based distance detection method of claim 1, wherein, When in the close-range detection mode, the processing of the reflected light according to the detection mode and the calculation of the distance of the target comprise: conversion processing is performed on the reflected light to obtain trigger time data; lens parameters are obtained, and a second histogram is obtained by removing the lens parameters, the lens parameters being trigger time data corresponding to the distance of the lens; a time of flight corresponding to a highest peak is obtained according to the second histogram, and the distance of the target is calculated according to the time of flight.

4. The time-of-flight based distance detection method according to claim 3, characterized in that, Before the lens parameters are obtained, the method further comprises: IDs of pixel units in the opening region are all set to the same value, and data sensed by the pixel units are all counted into a same histogram unit.

5. The time-of-flight based distance detection method according to claim 4, characterized in that, The obtaining of the time of flight corresponding to the highest peak according to the second histogram and the calculation of the distance of the target according to the time of flight specifically comprise: a pulse width of the highest peak of the second histogram is compared with a pulse width of an emission pulse; if the pulse widths are inconsistent, the highest peak is removed, and then a second highest peak is found until the peak meets the pulse width of the emission pulse, and the peak is taken as a matching peak; a time of flight corresponding to the matching peak is obtained, and the distance of the target is calculated according to the time of flight.

6. The time-of-flight based distance detection method according to any one of claims 1, 3-5, characterized in that, The shape of the opening region is the same as that of the lens, and an offset angle between the center of the opening region and the center of the lens is smaller than a preset angle.

7. The time-of-flight based distance detection method according to any one of claims 1, 3-5, characterized in that, The number of pixel units in the opening region is 1-10.

8. A time-of-flight based distance detection system, characterized by The method comprises: a transmission module for emitting a probe light beam, at least part of the probe light beam transmits through a lens and is emitted to a target; a receiving module comprising a pixel array, for receiving reflected light reflected by the target; A control module is configured to control the emission module to emit a probe light beam, adjust an opening region of the pixel array according to a detection mode, and perform corresponding noise removal processing on the reflected light according to the detection mode, wherein the noise removal processing is configured to eliminate near interference including a lens in a non-close-range detection mode and eliminate reflection interference caused by the lens in a close-range detection mode, and calculate a distance of the target; When in the non-close-range detection mode, all pixels in the pixel array are controlled to be turned on; and when in the close-range detection mode, part of the pixels in the pixel array are controlled to be turned on to form the opening region. The opening region includes at least one turned-on pixel.

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