A ranging method and apparatus

Abstract

The application provides a ranging method and device. The method comprises the following steps: emitting probe light to a target; determining the position of a scattered light spot reflected by the target on a pixel array; judging the distance interval in which the target is located according to the position of the scattered light spot; determining a measurement pixel for ranging according to the distance interval; and calculating the distance of the target according to the probe light reflected by the target and obtained by the measurement pixel. The measurement pixel for formal ranging is flexibly determined according to the distance interval in which the target is located, so that the ranging can be performed at a position avoiding the overstrong light spot energy when the distance is short, the drift error caused by the accumulation effect is eliminated without improving the hardware cost, and the ranging accuracy is improved.

Description

Technical Field

[0001] This invention relates to the field of distance detection technology, and in particular to a distance measurement method and apparatus. Background Technology

[0002] In the field of ranging, dToF (direct time of flight) technology involves emitting pulsed light towards a target object and using a high-performance photoelectric sensor to receive the pulsed light reflected back from the target object. The time it takes for the emitted light to return is measured using a statistical histogram, thus enabling depth detection, i.e., distance measurement. Single-photon avalanche diodes (SPADs) are currently the most commonly used photoelectric sensors in dToF depth sensing chips.

[0003] When measuring objects at close range, the SPAD dToF system can cause a pile-up effect, where the number of received photons increases rapidly due to excessively strong reflected light. This results in the entire measurement waveform being closer to the front end, leading to a misjudgment of the distance and causing a walk error.

[0004] To address the issue of inaccurate ranging due to the stacking effect, some current solutions combine SPADs with different photon detection efficiencies, using low-efficiency SPADs for short distances and high-efficiency SPADs for long distances to reduce the impact of the stacking effect. Other solutions correct the ranging results through algorithmic compensation. However, the first approach requires more SPADs at a uniform resolution, increasing the cost of measurement hardware. The second approach introduces new errors during algorithmic compensation, making it difficult to achieve low-cost and accurate error elimination, thus affecting ranging accuracy. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a ranging method and apparatus to eliminate drift error caused by the stacking effect and improve ranging accuracy without increasing hardware costs.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The first aspect of this invention provides a ranging method, comprising the following steps:

[0008] Firing a probe beam toward the target;

[0009] Determine the position of the scattered light spots reflected back from the target on the pixel array;

[0010] The distance range of the target is determined based on the position of the scattered light spots;

[0011] The measurement pixels used for ranging are determined based on the distance range;

[0012] The distance to the target is calculated based on the probe light reflected back from the target obtained by the measured pixels.

[0013] In one embodiment, determining the measuring pixels for ranging based on the distance interval specifically includes:

[0014] When the target is in any distance range, the position on the pixel array that can receive the light spot reflected back from a long distance is determined as the measurement pixel.

[0015] In one embodiment, determining the measurement pixels for ranging based on the distance range specifically includes:

[0016] When the target is in a long distance range, the position on the pixel array that can receive the light spot reflected back from the long distance target is determined as the measurement pixel;

[0017] When the target is in the close range, the position after moving a certain number of pixels in a preset direction based on the position where the light spot reflected back from the close target can be received is determined as the measurement pixel.

[0018] In one embodiment, when the target is in a close-range interval, the closer the distance interval of the target is to the pixel array, the more pixels are moved when determining the measured pixel.

[0019] In one embodiment, the preset direction is along the baseline and close to the direction from which the light spot reflected back from a distant target can be received.

[0020] In one embodiment, the number of pixels moved when determining the measurement pixel ranges from 1 to 4.

[0021] In one embodiment, the location where the reflected light spot from a distant target can be received is obtained by the following steps:

[0022] Control the target to move from near to far;

[0023] A probe light is emitted toward a moving target to acquire data on the change in position of a calibration spot on the pixel array returned by the target as a function of distance.

[0024] Based on the change data, when the change in the position of the calibration spot with distance is less than a preset offset, the current distance is determined as a long distance, and the position of the current calibration spot is determined as a position that can receive the light spot reflected back from the long distance target.

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

[0026] A transmitter used to emit probe light toward a target;

[0027] A pixel array for receiving probe light reflected back from the target;

[0028] The control module is used to determine the position of the scattered light spots reflected back by the target on the pixel array; determine the distance range of the target based on the position of the scattered light spots; determine the measuring pixels for distance measurement based on the distance range; and calculate the distance of the target based on the detection light reflected back by the target obtained by the measuring pixels.

[0029] In one embodiment, the control module is specifically used for:

[0030] When the target is in any distance range, the position on the pixel array that can receive the light spot reflected back from a long distance is determined as the measurement pixel.

[0031] In one embodiment, the control module is specifically used for:

[0032] When the target is in a long distance range, the position on the pixel array that can receive the light spot reflected back from the long distance target is determined as the measurement pixel;

[0033] When the target is in the close-range region, the measurement pixel is determined by moving the position of the light spot reflected back from the close-range target several pixels in a preset direction.

[0034] The beneficial effects of this invention are as follows: It provides a ranging method and apparatus that flexibly determines the measuring pixels used for formal ranging by the distance range of the target, so that the ranging can be performed at close range by avoiding the position of excessive light spot energy, eliminating the drift error caused by the stacking effect without increasing hardware costs, and improving the ranging accuracy. 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 the ranging method in an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram illustrating the positional relationship between scattered light spots and measurement pixels in existing technology.

[0038] Figure 3 This is a schematic diagram illustrating the positional relationship between scattered light spots and measurement pixels in an embodiment of the present invention;

[0039] Figure 4 This is a schematic diagram of the optical path for ranging targets at different distances in an embodiment of the present invention;

[0040] Figure 5 This is a schematic diagram showing the positions of scattered light spots reflected from targets at different distances in an embodiment of the present invention.

[0041] Figure 6 This is a schematic diagram illustrating the change of pixel row number with time box in an embodiment of the present invention;

[0042] Figure 7 This is a structural diagram of the ranging device in an embodiment of the present invention. Detailed Implementation

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] The ranging method provided in this invention is applied to a scatter depth sensor based on dTOF (direct time of flight) technology. This depth sensor includes at least a controller, a transmitter, and a receiver. The controller is connected to both the transmitter and the receiver. The transmitter emits a probe beam towards a target object, and at least a portion of the probe beam is reflected by the target object to form reflected light. The receiver receives the reflected light from the target object. The controller synchronously controls the emission and reception of light, performs histogram statistics on the photons received by the receiver using time bins, and then calculates the time of flight of the photons using the histogram to obtain the depth value of the corresponding pixel, thus achieving distance measurement between the target object and the sensor.

[0048] Specifically, the transmitter may include a driver and a light source, etc. The light source may be a light-emitting diode (LED), a laser diode (LD), an edge-emitting laser (EEL), a vertical-cavity surface-emitting laser (VCSEL), a picosecond laser, etc. Under the driving control of the driver, the light source emits a detection beam outward. The detection beam may be visible light, infrared light, ultraviolet light, etc. At least a portion of the detection beam is emitted toward the target object, and the reflected light generated by the reflection of at least a portion of the detection beam by the target object is received by the receiver.

[0049] The receiver may include a pixel array and receiving optical elements, which may be one or more combinations of lenses, microlens arrays, mirrors, etc. The receiving optical elements receive reflected light and guide it to the pixel array. The pixel array includes multiple pixels that collect photons. In one embodiment, the pixel array consists of multiple single-photon avalanche photodiodes (SPADs). The SPADs can respond to the incident single photon and output a photon signal indicating the arrival time of the received photon at each SPAD. Of course, in other embodiments, photoelectric conversion devices such as avalanche photodiodes, photomultiplier tubes, silicon photomultiplier tubes, etc., may also be used.

[0050] SPADs operating in Geiger mode output a photosensitive signal after being triggered by a photon avalanche. After an avalanche, the SPAD needs to be reset to return to Geiger mode and be able to sense photons again. Therefore, SPADs have a dead time when they cannot sense photons. Based on this characteristic, if the reflected light signal is too strong during ranging, for example, when measuring a nearby object, the light signal at a certain position on the rising edge of the reflected light waveform may be sufficient to trigger the SPAD, causing it to avalanche and enter the dead time. This results in the light signal at the highest waveform position of the subsequent reflected light not being sensed and losing its count. Consequently, the histogram count value at that timestamp decreases, causing the peak of the entire histogram waveform to occur earlier, resulting in a pile-up effect.

[0051] To address the issue of inaccurate ranging caused by the stacking effect in SPAD dToF systems when measuring near-field objects, some current solutions combine SPADs with different photon detection efficiencies, using low-efficiency SPADs for near-field measurements and high-efficiency SPADs for far-field measurements to reduce the impact of the stacking effect. Other solutions correct the ranging results through algorithmic compensation. However, the former approach requires more SPADs at the same resolution, while the latter introduces new errors during algorithmic compensation. Therefore, this invention describes a ranging method applied to a scattered depth sensing system to address this problem, eliminating drift errors caused by the stacking effect without increasing hardware costs, thus improving ranging accuracy.

[0052] like Figure 1 As shown, Figure 1 This is a flowchart of a ranging method in one embodiment of the present invention, which specifically includes the following steps:

[0053] S101, Emit probe light toward the target.

[0054] In this embodiment, the light source is driven by the driver to emit probe light toward the target. At this time, all pixels in the pixel array are turned on for initial exposure, and the light signal reflected back by the target is collected.

[0055] S102. Determine the position of the scattered light spots reflected back from the target on the pixel array.

[0056] Based on the light signal reflected back from the target, each pixel in the pixel array responds to a single incident photon. For example, it outputs "0" when there is no signal in the corresponding timebox and "1" when there is a signal. The TDC (Time-to-Digital Converter) readout circuit processes the photon signals output by each pixel to obtain the photon count value corresponding to different timeboxes. When the flight time falls within a certain timebox, the stored value for that timebox is incremented by "1". Since the light intensity of the speckle pattern is normally distributed with the strongest energy at the center of the speckle, pixels closer to the center of the speckle receive more photons. Therefore, after the initial exposure time, the position of the speckle pattern reflected back from the target can be determined by the cumulative value of the photon energy received by each pixel (i.e., the sum of the photon count values ​​of all timeboxes). For example, the pixel or multiple adjacent pixels with the highest cumulative photon energy value exceeding a preset threshold can be identified as the position of the speckle pattern.

[0057] S103. Determine the distance range of the target based on the position of the scattered light spots.

[0058] like Figure 2As shown, in a scattered SPAD ranging system, due to the parallax effect caused by the distance between the receiver and transmitter, the position of the scattered light spot reflected back by the target object in the pixel array changes with the distance between the target and the ranging system. Figure 3 As shown, due to parallax, the position of the scattered light spot in the pixel array shifts. The shift is more pronounced when the distance is closer (shorter flight time), and less pronounced until it stops when the distance is farther (longer flight time). Therefore, based on the position of the scattered light spot, the distance range of the target can be quickly determined. For example, the distance range corresponding to each or multiple rows of pixels can be pre-labeled, and the distance range of the target can be obtained by matching the row where the scattered light spot is located with the labeled data. This eliminates the need to construct a histogram and perform peak finding and distance calculations, effectively improving data processing efficiency.

[0059] S104. Determine the measurement pixels used for distance measurement based on the distance range.

[0060] In conventional ranging systems, such as Figure 4 As shown, the strongest light spot, i.e. the pixel where the scattered light spot reflected back from the target is located, is usually selected for ranging. In this way, when measuring at close range, the intensity of the light at a certain position on the rising edge of the light waveform is high enough to trigger SPAD. However, when the highest light waveform returns, the SPAD is already deadtime due to the previous trigger, which causes the histogram count value on that time box to decrease instead, resulting in drift error.

[0061] This embodiment no longer always selects the pixel containing the scattered light spot for distance measurement. Instead, it flexibly determines and activates the measurement pixels for distance measurement based on the current distance range of the target. For example, there is generally no accumulation effect when measuring at long distances, so the position of the measurement pixel can be consistent with the position of the scattered light spot to ensure the strongest reflected light energy is obtained when measuring at long distances, maximizing the distance measurement capability; while at close distances, such as Figure 5 As shown, the position of the measuring pixel is kept at a certain distance from the position of the scattered light spot, so that when the measuring pixel receives reflected light at close range, it is no longer in the position of the strongest energy of the light spot. The light intensity is attenuated to a certain extent, and the distance measurement can be avoided in the position of excessive light spot energy. Therefore, the problem of stacking effect is reduced, and thus the drift error is reduced.

[0062] S105. The distance to the target is calculated based on the detection light reflected back from the target obtained by the measurement pixel.

[0063] After determining the corresponding measurement pixels based on different distance ranges, a histogram can be constructed based on the detection light reflected back from the target obtained by the measurement pixels, and the flight time can be determined. Then, the target distance can be calculated, which allows for adapting to measurement requirements at different distances without increasing hardware costs, eliminating drift errors caused by the stacking effect at close range, and improving ranging accuracy.

[0064] In one embodiment, step S104 specifically includes:

[0065] When the target is in any distance range, the position on the pixel array that can receive the light spot reflected back from a long distance is determined as the measurement pixel.

[0066] In this embodiment, the position of the measuring pixel remains fixed. Regardless of the target's distance range, the position on the pixel array that can receive the light spot reflected back from a long distance is determined as the measuring pixel. Due to parallax, the position of the scattered light spot will change with distance, such as... Figure 3 and Figure 6 As shown, when the target object moves from far to near, the light spot moves along the baseline from positions 7 and 8 to positions 1 and 2. Once the target and the pixel array exceed a certain distance, the light spot stops moving at position 8. Therefore, by utilizing this parallax characteristic and the light spot energy distribution, the measuring pixels for actual ranging are fixed at positions that can receive the light spot reflected back from a distance. For example, the four SPADs in the shaded area of ​​rows 7 and 8 are fixed as measuring pixels. This ensures that the strongest reflected light energy is always obtained during long-distance measurements, guaranteeing the accuracy of long-distance measurements. During close-range measurements, due to parallax, there is a slight offset of several pixels between the reflected scattered light spot and the currently fixed measuring pixels. This ensures that the measuring pixels are not located at the SPADs where the scattered light spot is located, and that the measuring pixels are no longer at the position of strongest light energy when receiving reflected light at close range. This effectively reduces the accumulation effect caused by excessively strong reflected light and lowers drift errors.

[0067] In one embodiment, step S104 specifically includes:

[0068] When the target is in a long distance range, the position on the pixel array that can receive the light spot reflected back from the long distance target is determined as the measurement pixel;

[0069] When the target is in the close range, the position after moving a certain number of pixels in a preset direction based on the position where the light spot reflected back from the close target can be received is determined as the measurement pixel.

[0070] In this embodiment, the position of the measuring pixel is dynamically adjusted according to the distance range of the target. After the initial exposure, if the target is determined to be in the far-distance range, similar to the previous embodiment, the measuring pixel is fixed at a position on the pixel array that can receive the light spot reflected back from the far-distance target to ensure optimal distance measurement capability. If the target is determined to be in the near-distance range, the measuring pixel is determined by moving it several pixels in a preset direction from the position that can receive the light spot reflected back from the near-distance target, in order to avoid the pixel with the highest energy at the location of the light spot.

[0071] Specifically, the preset direction is along the baseline. It can be close to the direction of the light spot reflected back from the distant target or far away from the direction of the light spot reflected back from the distant target. As long as there is a certain distance between it and the scattered light spot of the current measurement target, the influence of the accumulation effect can be effectively reduced.

[0072] Specifically, the long-distance and short-distance ranges can be quickly determined using a pre-defined association table between pixel row numbers and distance (time of flight). For example, the distance range corresponding to each row of pixels can be pre-defined. Pixel row numbers greater than the preset distance range correspond to the long-distance range, while those less than the preset distance range correspond to the short-distance range. After the initial exposure, the pixel row number of the scattered light spot can be used to quickly determine whether it is a long-distance or short-distance target, making the determination method efficient and convenient. Of course, in other embodiments, the range can also be divided based on specific distance values. The target's distance value can be calculated based on the histogram data from the initial exposure. If the target's distance value is greater than the preset distance, it is determined to be in the long-distance range; if it is less than the preset distance, it is determined to be in the short-distance range, achieving a more accurate distance range determination.

[0073] In one embodiment, when the target is in a close-range interval, the closer the distance interval of the target is to the pixel array, the more pixels are moved when determining the measured pixel.

[0074] In this embodiment, since the movement of the light spot caused by parallax increases with decreasing distance, when the target is in the close range, the closer the target is to the pixel array, the more pixels need to be moved when determining the measurement pixel to ensure that the measurement pixel avoids the pixel position with the strongest light spot energy. Preferably, the number of pixels moved is in the range of 1-4 to avoid excessive movement affecting the measurement of other light spots. For example, within a distance of 0.1-0.35m, 3 pixels need to be moved along the baseline when determining the measurement pixel; within a distance of 0.35-0.7m, 2 pixels need to be moved along the baseline; within a distance of 0.7-1.3m, 1 pixel needs to be moved along the baseline; and beyond a distance of 1.3m, 0 pixels need to be moved. This cleverly combines parallax characteristics to achieve interval-based dynamic measurement pixel adjustment, adapting to the needs of measurement pixel adjustment in different refined distance ranges. In close-range measurement, the drift error caused by the stacking effect can be reduced without adding new hardware and compensation algorithms.

[0075] In one embodiment, the preset direction is along the baseline and close to the direction from which the light spot reflected back from a distant target can be received.

[0076] In this embodiment, when the target is in the near range, the offset of the measured pixels is based on the position of the target's reflected light spot along the baseline and close to the direction of the reflected light spot from the distant target. For example... Figure 6 If the scattered light spots reflected back from the current near target are located at positions 1 and 2 in the upper row of the pixel array, the position of the measurement pixel is determined by moving the light spot position upwards by several pixels (such as positions 3 and 4 in the upper row). This ensures that when switching to measuring distant targets, the position of the measurement pixel is closer to the position of the measurement pixel corresponding to the distant range, and the adjustment of the position of the measurement pixel will not be too large, thus improving the working stability of the system.

[0077] In one embodiment, the location where the reflected light spot from a distant target can be received is obtained by the following steps:

[0078] Control the target to move from near to far;

[0079] A probe light is emitted toward a moving target to acquire data on the change in position of a calibration spot on the pixel array returned by the target as a function of distance.

[0080] Based on the change data, when the change in the position of the calibration spot with distance is less than a preset offset, the current distance is determined as a long distance, and the position of the current calibration spot is determined as a position that can receive the light spot reflected back from the long distance target.

[0081] In this embodiment, when determining the position of the light spot corresponding to a distant target, calibration is performed using the position offset of the light spot on the pixel array. By controlling the target to move from near to far, the position change of the reflected light spot is monitored. Due to the parallax characteristic, the light spot offset becomes smaller with increasing distance. Therefore, the position of the calibrated light spot also decreases with increasing distance. When it is less than a preset offset, the current target distance is determined to be far. For example, by controlling the target to move towards infinity at different distances, the offset of the calibrated light spot along the baseline direction is obtained. When the offset of the calibrated light spot is less than 0.3 pixels when the target moves from distance x towards infinity, it is determined to be far if the offset is greater than x, and near if the offset is less than x. Based on the calibrated spot position corresponding to the long distance, the position that can receive the spot reflected back from the distant target is determined, thereby realizing the distinction between long distance and short distance. This allows for targeted selection of the measurement pixel position at different distances. Whether the measurement pixels are fixed or dynamically adjusted, the parallax characteristics can be combined to effectively reduce the drift error caused by the stacking effect and improve the ranging accuracy.

[0082] 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.

[0083] The present invention also provides a ranging device, such as... Figure 7 As shown, Figure 7 This is a structural diagram of a ranging device according to one embodiment of the present invention, which includes a transmitter 701, a pixel array 702, and a control module 703, wherein both the transmitter 701 and the pixel array 702 are connected to the control module 703. The transmitter 701 is used to emit detection light towards a target; the pixel array 702 is used to receive the detection light reflected back from the target; the control module 703 is used to determine the position of the scattered light spots reflected back from the target on the pixel array 702; determine the measuring pixels used for ranging based on the position of the scattered light spots; and activate the measuring pixels to sense the detection light reflected back from the target to obtain the distance to the target.

[0084] In one embodiment, the control module 703 is specifically used for:

[0085] When the target is in any distance range, the position on the pixel array 702 that can receive the light spot reflected back from a long distance is determined as the measurement pixel.

[0086] In one embodiment, the control module 703 is specifically used for:

[0087] When the target is in a long distance range, the position on the pixel array 702 that can receive the light spot reflected back from the long distance target is determined as the measurement pixel;

[0088] When the target is in the close range, the position after moving a few pixels in a preset direction based on the position where the light spot reflected back from the close target can be received is determined as the measurement pixel.

[0089] Since the above method embodiments have already described the ranging process in detail, please refer to the corresponding method embodiments above for details, and will not be repeated here.

[0090] In summary, this invention provides a ranging method and apparatus. The method includes emitting a probe light towards a target; determining the position of a scattered light spot reflected back from the target on a pixel array; determining the distance range of the target based on the position of the scattered light spot; determining a measuring pixel for ranging based on the distance range; and calculating the distance of the target based on the probe light reflected back from the target obtained by the measuring pixel. By flexibly determining the measuring pixel for formal ranging by using the distance range of the target, the method avoids positions with excessively strong light spot energy during close-range measurements, eliminating drift errors caused by the stacking effect without increasing hardware costs, and improving ranging accuracy.

[0091] 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 distance measurement method, characterized in that, Includes the following steps: Firing a probe beam toward the target; Based on the cumulative value of the photon energy received by each pixel, the position of the scattered light spot reflected back from the target on the pixel array is determined; Based on the distance interval corresponding to each or more rows of pixels pre-calibrated, the distance interval of the target is determined by matching the position of the scattered light spots with the calibrated data. The measurement pixels used for ranging are determined based on the distance range; The distance to the target is calculated based on the detection light reflected back from the target obtained by the measurement pixels; The step of determining the measurement pixels for ranging based on the distance interval specifically includes: When the target is in a long distance range, the position on the pixel array that can receive the light spot reflected back from the long distance target is determined as the measurement pixel, and the position of the measurement pixel is kept consistent with the position of the scattered light spot; When the target is in the close range, the position of the measurement pixel is determined by moving the position of the light spot reflected back from the close target in a preset direction by several pixels, and the position of the measurement pixel is kept at a certain distance from the position of the scattered light spot.

2. The ranging method according to claim 1, characterized in that, The step of determining the measurement pixels for ranging based on the distance interval specifically includes: When the target is in any distance range, the position on the pixel array that can receive the light spot reflected back from a long distance is determined as the measurement pixel.

3. The ranging method according to claim 1, characterized in that, When the target is in a close range, the closer the target is to the pixel array, the more pixels are moved when determining the measurement pixel.

4. The ranging method according to claim 1, characterized in that, The preset direction is along the baseline and close to the direction from which the light spot reflected back from a distant target can be received.

5. The ranging method according to claim 3, characterized in that, The number of pixels moved when determining the measured pixel ranges from 1 to 4.

6. The ranging method according to claim 1 or 2, characterized in that, The location where the reflected light spot from a distant target can be received is obtained by the following steps: Control the target to move from near to far; A probe light is emitted toward a moving target to acquire data on the change in position of a calibration spot on the pixel array returned by the target as a function of distance. Based on the change data, when the change in the position of the calibration spot with distance is less than a preset offset, the current distance is determined as a long distance, and the position of the current calibration spot is determined as a position that can receive the light spot reflected back from the long distance target.

7. A ranging device, characterized in that, include: A transmitter used to emit probe light toward a target; A pixel array for receiving probe light reflected back from the target; The control module is used to determine the position of the scattered light spot reflected back by the target on the pixel array based on the cumulative value of the photon energy received by each pixel; based on the distance interval corresponding to each or multiple rows of pixels in advance, it matches the position of the scattered light spot with the calibrated data to determine the distance interval in which the target is located; it determines the measurement pixel for ranging based on the distance interval; and it calculates the distance of the target based on the detection light reflected back by the target obtained by the measurement pixel. The control module is specifically used for: When the target is in a long distance range, the position on the pixel array that can receive the light spot reflected back from the long distance target is determined as the measurement pixel, and the position of the measurement pixel is kept consistent with the position of the scattered light spot; When the target is in the close range, the position of the measurement pixel is determined by moving the position of the light spot reflected back from the close target in a preset direction by several pixels, and the position of the measurement pixel is kept at a certain distance from the position of the scattered light spot.

8. The ranging device according to claim 7, characterized in that, The control module is specifically used for: When the target is in any distance range, the position on the pixel array that can receive the light spot reflected back from a long distance is determined as the measurement pixel.

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