Distance measuring method, distance measuring device and distance measuring equipment

Abstract

The present application proposes a distance measurement method, a distance measurement device, and a distance measurement equipment, and relates to the field of distance measurement technology. The distance measurement method includes: obtaining current echo data; determining the waveform state corresponding to the echo data; adjusting the emission power of the laser emitting tube according to the waveform state until the waveform state is in an unsaturated state; and determining the current test distance when the waveform state is in an unsaturated state. The present application obtains the current echo data, then determines the waveform state corresponding to the echo data, and adjusts the emission power of the laser emitting tube according to the waveform state until the waveform state is in an unsaturated state. Finally, when the waveform state is in an unsaturated state, the current test distance is determined. By improving the saturated waveform state, the emission voltage of the laser emitting tube is adjusted to adjust the laser emission power, thereby achieving the purpose of adjusting the received laser power and changing the saturation state of the echo signal, thereby significantly improving the stability and accuracy of the distance measurement.

Description

Technical Field

[0001] The present application relates to the field of distance measurement technology, and in particular to a distance measurement method, a distance measurement device, and a distance measurement equipment. Background Art

[0002] When laser ranging faces targets made of materials with different surface reflective properties, the light power received by the pulsed laser receiving system is seriously affected by variables such as the reflectivity, reflection azimuth, roughness, and color of the materials with different surface reflective properties, which seriously affects the ranging accuracy. Summary of the Invention

[0003] The main purpose of the present invention is to provide a distance measurement method, which aims to suppress echo signal saturation and improve distance measurement accuracy.

[0004] To achieve the above object, the present invention provides a distance measurement method, which is applied to a distance measurement device, wherein the distance measurement device includes a laser emitting tube, and the distance measurement method includes:

[0005] Get current echo data;

[0006] Determining a waveform state corresponding to the echo data;

[0007] Adjusting the emission power of the laser emitting tube according to the waveform state until the waveform state is in an unsaturated state;

[0008] When the waveform is in an unsaturated state, the distance of the current test is determined.

[0009] Optionally, adjusting the emission power of the laser emitting tube according to the waveform state until the waveform state is in an unsaturated state includes:

[0010] If the waveform state is a saturated state, reducing the driving voltage of the laser emitting tube according to a preset step size, wherein the preset step size is dynamically adjusted according to the target reflectivity or the ambient optical characteristics;

[0011] The echo data is reacquired to determine a new waveform state of the echo data until the waveform state is in an unsaturated state.

[0012] Optionally, if the waveform state is a saturation state, reducing the driving voltage of the laser emitting tube according to a preset step size includes:

[0013] If the waveform state is a saturation state, calculating a voltage difference between the current driving voltage and a theoretical saturation voltage corresponding to the target reflectivity or the ambient optical characteristic;

[0014] According to the voltage difference and the preset step size, the driving voltage of the laser emitting tube is gradually reduced;

[0015] The reacquiring echo data to determine a new waveform state of the echo data until the waveform state is in an unsaturated state includes:

[0016] After adjusting the driving voltage of the laser emitting tube, reacquiring echo data to determine a new waveform state of the echo data;

[0017] If the waveform is in a saturated state, the driving voltage of the laser emitting tube is reduced again.

[0018] Optionally, adjusting the emission power of the laser emitting tube according to the waveform state until the waveform state is in an unsaturated state includes:

[0019] If the waveform state is a saturation state, calculating a voltage difference between the current driving voltage and a theoretical saturation voltage corresponding to the target reflectivity or the ambient optical characteristic;

[0020] Adjusting the driving voltage of the laser emitting tube to within a theoretical saturation voltage range according to the voltage difference, so that the waveform state is in an unsaturated state;

[0021] The echo data is reacquired to determine a new waveform state of the echo data until the waveform state is in an unsaturated state.

[0022] Optionally, when the waveform state is in an unsaturated state, determining the distance of the current test includes:

[0023] When the waveform state is in an unsaturated state, a time difference between laser pulse emission and echo signal reception is recorded by a timer;

[0024] The distance of the current test corresponding to the time difference is calculated according to the speed of light distance formula.

[0025] Optionally, determining the waveform state corresponding to the echo data includes:

[0026] Detecting a distribution condition of the echo data at an upper limit of a voltage range;

[0027] If there are multiple echo data at the upper limit of the voltage range, determining that the waveform state is a saturation state;

[0028] If the voltage of the echo data does not reach the upper limit of the voltage range, it is determined that the waveform state is an unsaturated state.

[0029] Optionally, the ranging method further includes:

[0030] Get the distance prediction value of the target point to be measured;

[0031] Setting a reference voltage according to the distance prediction value, wherein the reference voltage is a critical saturation voltage set according to a maximum reflectivity target;

[0032] The reference voltage is set as the upper limit of the voltage range.

[0033] Optionally, the distance measuring device includes an avalanche diode;

[0034] The obtaining of current echo data comprises:

[0035] The laser pulse reflected by the target is received by the avalanche diode, generating a corresponding echo electrical signal;

[0036] After the echo electrical signal is amplified, it is digitally converted to generate the current echo data.

[0037] In addition, to achieve the above-mentioned purpose, the present invention also provides a ranging device, which includes: a memory, a processor, and a ranging program stored in the memory and executable on the processor, wherein the ranging program is configured to implement the ranging method described above.

[0038] In addition, to achieve the above-mentioned purpose, the present invention also provides a distance measuring device, including the distance measuring device as described above.

[0039] The embodiment of the present invention obtains current echo data, determines the waveform state corresponding to the echo data, and adjusts the emission power of the laser emitting tube according to the waveform state until the waveform state is in an unsaturated state. Finally, when the waveform state is in an unsaturated state, the current test distance is determined. By improving the saturated waveform state and adjusting the emission voltage of the laser emitting tube to adjust the laser emission power, the purpose of adjusting the received laser power is achieved, and the saturation state of the echo signal is changed, thereby significantly improving the stability and accuracy of the ranging. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0042] Figure 1 This is a flow chart of a distance measurement method according to an embodiment of the present invention;

[0043] Figure 2 This is a flow chart of a distance measurement method according to another embodiment of the present invention;

[0044] Figure 3 This is a flow chart of a distance measurement method according to another embodiment of the present invention;

[0045] Figure 4 This is a flow chart of a distance measurement method according to another embodiment of the present invention;

[0046] Figure 5 This is a flow chart of a distance measurement method according to another embodiment of the present invention;

[0047] Figure 6 This is a flow chart of a distance measurement method according to another embodiment of the present invention;

[0048] Figure 7 This is a flow chart of a distance measurement method according to another embodiment of the present invention;

[0049] Figure 8 This is a flow chart of a distance measurement method according to another embodiment of the present invention;

[0050] Figure 9 is a structural block diagram of the distance measuring device of the present invention;

[0051] Figure 10 This is a waveform diagram of the echo signal of the ranging method of the present invention.

[0052] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0053] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, and the well-known modules, units and their connections, links, communications or operations are not shown or described in detail. In addition, the described features, architectures or functions can be combined in any way in one or more embodiments. It should be understood by those skilled in the art that the various embodiments described below are only for illustration and are not intended to limit the scope of protection of the present invention. It can also be easily understood that the modules or units or processing methods in the various embodiments described herein and shown in the drawings can be combined and designed according to various different configurations. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0054] The definitions of various nouns or methods in the following embodiments, except for those that are logically untenable, are generally based on the broad concepts that can be implemented under the premise of the disclosure in the embodiments. Under such an understanding, the various specific subordinate specific definitions of the nouns or methods should be regarded as the inventive content of the present invention, and should not be narrowly understood or interpreted in a biased manner on the grounds that the specification does not disclose such specific definitions. Similarly, under the premise that it can be logically implemented, the order of the steps in the method is flexible and changeable, and the specific subordinate specific definitions of the broad concepts of various nouns or methods are all within the scope of protection of the present invention.

[0055] The existing pulse laser ranging process uses a laser to emit laser pulses to the target to be measured, and uses a detector to sample the emitted laser pulses to trigger the time measurement system of the rangefinder to start timing. After the light pulse reaches the target, it returns to the detector of the laser rangefinder through diffuse reflection, generating a signal to stop timing, and then the target distance is calculated based on the speed of light.

[0056] Since different targets have their own material surface reflection characteristics, the reflectivity, reflection azimuth, roughness, color and other variables of the material will affect the optical power received by the pulsed laser receiving system to a certain extent, causing the echo signal to present different sizes. The echo signal of high reflectivity or close-range targets will be saturated, thereby affecting the ranging accuracy of the measurement range.

[0057] The main solution of the embodiment of the present application is: by obtaining the current echo data, then determining the waveform state corresponding to the echo data, and adjusting the emission power of the laser transmitting tube according to the waveform state until the waveform state is in an unsaturated state, and finally determining the current test distance when the waveform state is in an unsaturated state.

[0058] In this embodiment, for ease of description, the following description is made with the distance measuring device as the execution subject.

[0059] The present application provides a solution by improving the saturated waveform state and adjusting the emission voltage of the laser transmitting tube to adjust the laser emission power, thereby achieving the purpose of adjusting the received laser power and changing the saturation state of the echo signal, thereby significantly improving the stability and accuracy of ranging.

[0060] To this end, the present invention proposes a ranging method. It is understandable that a ranging device is provided in the ranging device for storing and executing the following method. The ranging device can be implemented using a main controller, such as an MCU (Microcontroller Unit), a DSP (Digital Signal Process), an FPGA (Field Programmable Gate Array), a SOC (System on Chip), etc.

[0061] Existing laser ranging equipment, when used with targets made of materials with varying reflectivity, faces the risk of saturation in the echo signal due to differences in reflectivity. When the target surface is highly reflective, the echo signal exceeds the upper limit of the device's range, causing waveform and data distortion, ultimately leading to inaccurate ranging results. Traditional methods employ a fixed transmit power mode, which cannot effectively handle dynamic signal changes in complex reflective environments.

[0062] To address this issue, research has identified echo signal saturation as a key factor limiting ranging accuracy. By analyzing the correlation between echo waveform characteristics and transmit power, a dynamic closed-loop adjustment mechanism was proposed. This mechanism monitors the waveform in real time to determine whether the system is in the saturation operating zone and triggers power adjustment. The power adjustment process balances signal strength and noise levels, eliminating saturation while maintaining a valid echo.

[0063] It is also important to understand that, with reference to Figure 9 The distance measurement method of this embodiment is applied to a distance measurement device, which includes a laser emitting tube.

[0064] Based on the above, refer to Figure 1 as well as Figure 10 In one embodiment of the present invention, the distance measurement method includes steps S100-S400, wherein:

[0065] S100, obtaining current echo data;

[0066] S200, determining the waveform state corresponding to the echo data;

[0067] S300, adjusting the emission power of the laser emitting tube according to the waveform state until the waveform state is in an unsaturated state;

[0068] S400: When the waveform is in an unsaturated state, determine a distance of a current test.

[0069] The waveform state refers to the distribution characteristics of the echo signal within the voltage range. This can be determined by checking whether the signal peak value remains at the upper limit of the range. For example, when three consecutive sampled values ​​reach the maximum value of the analog-to-digital converter, it is determined to be saturated. Transmit power adjustment refers to controlling the light intensity output by changing the laser tube drive voltage. This can be achieved by gradually reducing the voltage or directly jumping to the theoretical value. The theoretical value is pre-calculated based on the target reflectivity model.

[0070] The device continuously collects the digitized echo signal generated by the reflected laser and identifies saturation by statistically analyzing the peak distribution. If a continuous out-of-range signal is detected, the control unit immediately reduces the drive voltage and laser emission intensity to return the echo amplitude to the effective detection range. After adjustment, the signal is collected again for status verification, and the cycle continues until a stable, unsaturated waveform is achieved. Finally, the round-trip time difference of the optical pulse is calculated using the time-of-flight method, which is converted into a precise distance value.

[0071] Among them, Figure 10 As shown, when the waveforms of signal 1 and signal 2 are both saturated, the emission power of the laser emission tube needs to be adjusted until the waveform reaches the unsaturated state of signal 3.

[0072] Among them, Figure 9 As shown, the transmitted optical power is adjusted by adjusting the voltage of the high-voltage transmitting module. After the laser reaches the target, it reflects back to the receiving circuit, where it is received by the avalanche diode and converted into electrical energy. This energy is then amplified by the amplifier circuit and converted into a digital signal by the high-speed ADC. The FPGA collects the signal and transmits it to the MCU, which analyzes and detects the received echo signal and calculates the distance. The FPGA also controls laser emission and timing. Before a measurement, the target is predicted and its reflectivity is pre-determined. The transmit voltage is then adjusted to adjust the laser transmit power, finding the optimal transmit voltage for the current target's reflection. This adjusted voltage is then used for measurement. Adjusting the laser tube voltage to change the laser transmit power suppresses echo signal saturation and improves echo signal identification accuracy.

[0073] Compared to existing technologies, traditional solutions require manual intervention to adjust device parameters when encountering highly reflective targets. This embodiment's ranging method achieves fully automatic closed-loop control. Existing technologies use fixed thresholds to determine saturation, which can easily lead to misjudgments. This embodiment improves the reliability of state recognition through continuous sampling point analysis. Conventional power regulation methods carry the risk of overshoot and oscillation. This embodiment combines theoretical models with a step-by-step regulation strategy to ensure rapid convergence.

[0074] Through the above-mentioned technical means, this embodiment achieves adaptive ranging for targets with different reflective characteristics, eliminating measurement errors caused by signal saturation. The system can autonomously maintain the echo signal within the optimal detection range, ensuring ranging accuracy in complex optical environments while avoiding the tedious manual parameter adjustment.

[0075] This embodiment obtains current echo data, determines the waveform state corresponding to the echo data, and adjusts the emission power of the laser emitting tube according to the waveform state until the waveform state is in an unsaturated state. Finally, when the waveform state is in an unsaturated state, the current test distance is determined. By improving the saturated waveform state and adjusting the emission voltage of the laser emitting tube to adjust the laser emission power, the purpose of adjusting the received laser power is achieved, and the saturation state of the echo signal is changed, thereby significantly improving the stability and accuracy of the ranging.

[0076] Optionally, refer to Figure 2 Another embodiment of the present invention provides a ranging method based on the above Figure 1 In the embodiment shown, the emission power of the laser emitting tube is adjusted according to the waveform state until the waveform state is in an unsaturated state, including steps S310-S320, wherein:

[0077] S310: If the waveform is in a saturated state, reduce the driving voltage of the laser emitting tube according to a preset step size, where the preset step size is dynamically adjusted according to a target reflectivity or ambient optical characteristics;

[0078] S320 , reacquire echo data to determine a new waveform state of the echo data, until the waveform state is in an unsaturated state.

[0079] Among them, the preset step size refers to the amplitude of change in each adjustment of the driving voltage, which can be achieved by using a dynamic step size algorithm based on the calculation of the difference between the target reflectivity and the ambient light intensity. For example, the step size parameter is generated based on the reflectivity difference and the amplitude of the ambient light intensity change. The target reflectivity refers to the ratio parameter of the laser reflected by the surface of the object being measured. It can be calculated by reverse calculation using a pre-calibrated reflectivity database or real-time measurement of the echo signal intensity. The ambient optical characteristics refer to the background light intensity and spectral distribution in the current environment. The ambient light data can be collected by a photoelectric sensor and converted into an interference intensity assessment value. Dynamic adjustment refers to the optimization of the step size based on the real-time feedback of the reflectivity and ambient light parameters. For example, when the reflectivity is higher than the threshold or the ambient light interference increases, the voltage adjustment step size is automatically increased.

[0080] When the waveform corresponding to the echo data is detected to be in a saturated state, the ranging device calculates a preset step size based on the real-time parameters of the target reflectivity and the ambient optical properties. For example, a smaller step size is used when the reflectivity is high or the ambient light is weak. The driving voltage is then gradually reduced according to this step size, and after each adjustment, the laser emission is re-triggered and new echo data is collected. The voltage adjustment and waveform state detection are repeated until the echo waveform leaves the saturated state. During this process, the adjustment amplitude of the driving voltage is dynamically adapted to the target characteristics and environmental conditions, avoiding the problem of excessive or insufficient adjustments caused by a fixed step size.

[0081] Compared to existing technologies, traditional solutions typically use a fixed step size to adjust the driving voltage. This can lead to a surge in adjustments or fail to effectively eliminate saturation in scenarios with large reflectivity differences. This embodiment introduces a dynamic coupling mechanism between reflectivity and ambient light parameters, enabling the step size to adapt to target characteristics and ambient interference intensity, significantly improving voltage adjustment efficiency. Furthermore, by avoiding signal attenuation caused by over-adjustment, the echo waveform can be more reliably controlled within the non-saturation range.

[0082] Through the above-mentioned technical means, this embodiment solves the existing problems of low ranging efficiency and error accumulation caused by fixed voltage adjustment steps. The dynamic step-size mechanism can quickly eliminate waveform saturation even under highly reflective targets or in complex optical environments, ensuring that the ranging system can stably acquire valid echo signals in a variety of scenarios. Furthermore, this solution avoids the energy loss caused by multiple ineffective adjustments in traditional methods, thereby extending the service life of the laser transmitter.

[0083] Optionally, refer to Figure 3 Another embodiment of the present invention provides a ranging method based on the above Figure 2 In the embodiment shown, if the waveform state is a saturated state, the driving voltage of the laser emitting tube is reduced according to a preset step size, including steps S311-S312, wherein:

[0084] S311, if the waveform state is a saturation state, calculating the voltage difference between the current driving voltage and the theoretical saturation voltage corresponding to the target reflectivity or the ambient optical characteristic;

[0085] S312: According to the voltage difference and the preset step size, the driving voltage of the laser emitting tube is gradually reduced.

[0086] The reacquisition of echo data to determine a new waveform state of the echo data until the waveform state is in an unsaturated state includes steps S321-S322, wherein:

[0087] S321, after adjusting the driving voltage of the laser emitting tube, reacquire the echo data to determine a new waveform state of the echo data;

[0088] S322: If the waveform is in a saturated state, reduce the driving voltage of the laser emitting tube again.

[0089] Among them, the current driving voltage refers to the voltage value actually output by the laser emitting tube in the saturation state, which can be achieved through real-time acquisition by a voltage sensor and is used to characterize the actual state of the current laser emission power. The theoretical saturation voltage refers to the critical voltage value calculated based on the target reflectivity or environmental optical characteristics, which can be achieved through a reflectivity database or optical sensor feedback, and is used to reflect the ideal voltage range required to avoid echo signal saturation in the current environment. The voltage difference refers to the numerical difference between the current driving voltage and the theoretical saturation voltage, which can be achieved through subtraction or table comparison, and is used to quantify the amplitude by which the driving voltage needs to be adjusted. The preset step size refers to the gradient change of the driving voltage each time it is adjusted, which can be achieved by a dynamic step size algorithm or an adaptive step size based on the difference ratio, and is used to balance the adjustment speed and stability. Step-by-step reduction refers to the operation method of gradually reducing the driving voltage in stages, which can be achieved through multi-cycle iterative control or piecewise linear adjustment to avoid signal distortion caused by voltage mutations.

[0090] Among them, when the waveform state of the echo data is judged to be saturated, the theoretical saturation voltage is first calculated based on the target reflectivity or the ambient optical characteristics. For example, on a metal surface with a high reflectivity, the theoretical saturation voltage may be lower than the theoretical value of an ordinary material. Subsequently, the voltage difference is obtained by comparing the current driving voltage with the theoretical value, and the amplitude of each adjustment is determined according to the preset step size. For example, if the voltage difference is 5V and the preset step size is 1V, the driving voltage will be reduced step by step in five times. After each adjustment, the echo data is re-collected and the waveform state is detected. If saturation still exists, the driving voltage continues to be reduced. This process continues until the waveform state enters the unsaturated area, at which time the voltage adjustment is stopped and the distance calculation module is started.

[0091] Compared to existing technologies, traditional methods typically use fixed step sizes or single, large adjustments to the driving voltage. This can easily lead to under- or over-adjustment of the voltage due to sudden changes in ambient reflectivity, causing multiple invalid cycles or signal distortion. This embodiment, by dynamically calculating the theoretical saturation voltage and implementing graded adjustments based on the difference, can more accurately match environmental characteristics, avoid signal saturation, reduce the number of adjustments, and improve the response speed of the ranging device.

[0092] Through the above-mentioned technical means, this embodiment effectively solves the problem of echo signal saturation caused by reflectivity differences. Through the dynamic graded voltage adjustment mechanism, it ensures that the echo signals of targets of different materials are always within the resolvable range, thereby improving the ranging accuracy and equipment environmental adaptability.

[0093] Optionally, refer to Figure 4 Another embodiment of the present invention provides a distance measurement method based on the above Figure 1 In the embodiment shown, the emission power of the laser emitting tube is adjusted according to the waveform state until the waveform state is in an unsaturated state, including steps S330-S350, wherein:

[0094] S330: If the waveform state is a saturation state, calculate the voltage difference between the current driving voltage and the theoretical saturation voltage corresponding to the target reflectivity or the ambient optical characteristic;

[0095] S340, adjusting the driving voltage of the laser emitting tube to within a theoretical saturation voltage range according to the voltage difference, so that the waveform state is in an unsaturated state;

[0096] S350 , reacquire echo data to determine a new waveform state of the echo data, until the waveform state is in an unsaturated state.

[0097] Among them, the theoretical saturation voltage refers to the critical voltage threshold calculated by the physical model based on the target reflectivity or ambient optical parameters. It can be achieved through a preset reflectivity-voltage mapping table or ambient light compensation algorithm. Its role is to provide a scientific basis for voltage adjustment to avoid blind adjustment. The voltage difference refers to the quantitative deviation between the current driving voltage and the theoretical saturation voltage. It can be achieved by performing a difference operation on the voltage signal collected by the analog-to-digital converter. Its role is to determine the adjustment amplitude to quickly eliminate the saturation phenomenon. The theoretical saturation voltage range refers to the driving voltage range that allows the echo signal to be in the linear response range. It can be achieved by experimentally calibrating the upper and lower limits of the voltage corresponding to different reflectivity targets. Its role is to ensure that the dynamic range of the signal processing and ranging device adapts to the current measurement conditions.

[0098] When a continuous distribution of echo data at the upper limit of the voltage range is detected, the voltage difference that needs to be adjusted is calculated by comparing the current drive voltage with the voltage reference value output by the theoretical model. The laser emitter drive voltage is then adjusted once to within the theoretical saturation voltage range. For example, if the drive voltage is detected to be higher than the theoretical value, it is directly set to that theoretical value. After the voltage adjustment is completed, a new round of echo signal acquisition is immediately initiated. The adjustment effect is confirmed by verifying whether the newly acquired waveform has left the saturation region. If saturation still exists, the calculation and adjustment process is repeated until the unsaturated condition is met.

[0099] Compared to existing methods, which typically use a fixed-step, step-by-step voltage adjustment method that requires multiple iterations to reach the target voltage, this embodiment directly determines the adjustment range through theoretical model calculations, eliminating the time-consuming trial-and-error process inherent in traditional methods. For example, traditional methods require gradual voltage reduction and repeated testing, while this embodiment uses a physical model to predict the required voltage value, achieving the desired operating range with a single adjustment.

[0100] Through the above-mentioned technical means, this embodiment effectively solves the response delay problem caused by inefficient voltage regulation in traditional ranging equipment and significantly shortens the time it takes to eliminate saturation. Especially when facing high-reflectivity targets, this solution can quickly adjust the ranging device to the optimal operating state, avoiding the extended measurement cycle caused by multiple voltage adjustments, thereby ensuring the real-time and continuous ranging process.

[0101] Optionally, refer to Figure 5 Another embodiment of the present invention provides a distance measurement method based on the above Figure 1 In the embodiment shown, when the waveform state is in an unsaturated state, determining the distance of the current test includes steps S410-S420, wherein:

[0102] S410, when the waveform state is in an unsaturated state, recording the time difference between laser pulse emission and echo signal reception by a timer;

[0103] S420: Calculate the current test distance corresponding to the time difference according to the speed of light distance formula.

[0104] The time difference is recorded using a hardware module with high-precision timing capabilities. This can be achieved using a clock counter chip (such as a TDC) in an embedded distance measurement device, or through a timer in an FPGA module within the distance measurement device. Its timing accuracy can reach nanoseconds. The speed of light distance formula is based on the product of the time difference and the speed of light. This calculation can be performed using the processor's pre-set floating-point arithmetic module. The formula is distance equal to the speed of light multiplied by the time difference, divided by two.

[0105] When the distance measuring device determines that the echo data waveform is not saturated, it immediately triggers a timer to begin recording the laser pulse emission moment. After the avalanche diode receives the reflected laser signal, the timer stops and outputs the time difference. The processor inputs this time difference into a pre-set calculation module, which, combined with the speed of light constant, performs real-time calculations to ultimately output the precise distance value. This entire process, through the coordinated cooperation of hardware triggering and software calculation, ensures a seamless connection between time measurement and distance calculation.

[0106] Compared to existing technologies, traditional distance measurement devices directly calculate distance values ​​even when the signal is saturated, resulting in deviations in the time difference data due to signal distortion. However, the distance measurement method of this embodiment performs distance calculations only after confirming that the waveform is not saturated, avoiding timing errors caused by signal overload. Furthermore, by combining high-precision timing with real-time calculations, the reliability of the distance measurement data is significantly improved.

[0107] Through the above technical means, this embodiment effectively solves the problem of reduced ranging accuracy caused by echo signal saturation, and can stably output accurate distance values ​​in scenarios with targets of varying reflectivity. By optimizing the collaborative mechanism between timing and calculation, this solution improves the robustness of the ranging device in complex environments.

[0108] Optionally, refer to Figure 6 Another embodiment of the present invention provides a ranging method based on the above Figure 1 In the illustrated embodiment, determining the waveform state corresponding to the echo data includes steps S210-S230, wherein:

[0109] S210, detecting a distribution condition of the echo data at an upper limit of a voltage range;

[0110] S220: If there are multiple echo data at the upper limit of the voltage range, determine that the waveform state is a saturation state;

[0111] S230: If the voltage of the echo data does not reach the upper limit of the voltage range, determine that the waveform state is an unsaturated state.

[0112] The voltage range upper limit refers to the maximum voltage value that the analog-to-digital converter can measure. The maximum value of 255 for an 8-bit analog-to-digital converter can be used as the range upper limit. Signal saturation is determined by comparing the digital value of the echo signal with this upper limit. Reaching the range upper limit for multiple consecutive echo data points refers to the value of three or more adjacent sampling points being equal to the maximum value. This can be achieved using a sliding window algorithm or a point-by-point comparison algorithm. This effectively distinguishes between transient noise interference and true signal saturation, avoiding misjudgments. The saturation state determination logic detects multiple consecutive points reaching the upper limit, rather than a single peak exceeding the threshold. This reduces the probability of false triggering due to transient noise or interference and improves the accuracy of state judgment.

[0113] Among them, after the echo signal output by the analog-to-digital converter is obtained in digital form, the signal waveform is first scanned point by point to detect whether there are three consecutive sampling points with values ​​reaching 255. If so, it is determined that the received signal has exceeded the upper limit of the analog-to-digital converter. At this time, the signal is in a saturated state and cannot accurately reflect the true amplitude change of the echo signal. At this time, the transmission power adjustment mechanism needs to be triggered, such as reducing the driving voltage of the laser transmitting tube to avoid continuous saturation of the signal in subsequent measurements. If the values ​​of all sampling points are lower than 255, it is determined that the signal is not saturated and the time difference calculation stage can be entered directly. For example, in a laser ranging scenario, when the target reflectivity is high, the echo signal intensity may exceed the range of the analog-to-digital converter, resulting in the top of the signal being truncated. At this time, multiple consecutive sampling points appear as a fixed maximum value. This feature is used to reliably identify the saturation state.

[0114] Compared to existing technologies, traditional signal saturation detection typically only determines whether a single sampling point has reached an upper limit. However, transient interference or noise can cause a single sampling point to reach its maximum value, leading to false positives. By detecting saturation at multiple consecutive sampling points, incidental interference can be effectively filtered out, improving the robustness of state determination. For example, the threshold comparison method used in existing technologies can trigger erroneous adjustments due to single impulse noise. However, this embodiment, through the continuous point detection mechanism, reduces the probability of false positives by at least an order of magnitude.

[0115] Through the above-mentioned technical means, this embodiment can accurately distinguish between true signal saturation and transient noise interference, ensuring that distance calculations are performed in an unsaturated signal state, thereby improving the reliability of ranging results. This solution can effectively avoid waveform distortion caused by signal truncation, especially in highly reflective targets or close-range measurement scenarios, providing a reliable data foundation for subsequent power adjustment and time difference calculation.

[0116] Optionally, refer to Figure 7 Another embodiment of the present invention provides a ranging method based on the above Figure 6 In the embodiment shown, the ranging method further includes steps S500-S700, wherein:

[0117] S500, obtaining a distance prediction value of the target point to be measured;

[0118] S600, setting a reference voltage according to the distance prediction value, wherein the reference voltage is a critical saturation voltage set according to a maximum reflectivity target;

[0119] S700: Set the reference voltage as the upper limit of the voltage range.

[0120] like Figure 9 As shown in FIG, the setting range of the reference voltage is the highest driving voltage of the target within 20 meters, and the initial voltage loading is completed by the MCU and FPGA in collaboration.

[0121] Among them, the distance prediction value refers to the expected distance range between the target object and the ranging device estimated by pre-scanning or historical data. It can be achieved by pre-detection using the time-of-flight method or by selecting the target area based on the image recognition algorithm for estimation. It is used to guide the initial setting of the reference voltage. The reference voltage refers to the initial driving voltage set based on the critical saturation voltage value corresponding to the maximum reflectivity of the target. It can be generated by looking up a preset reflectivity-voltage correspondence table or dynamically based on the target material database to avoid directly entering the saturation state when the echo signal is collected. MCU and FPGA collaboration refers to the voltage parameter loading between the microcontroller unit and the field programmable gate array through bus communication. The SPI protocol can be used to transmit voltage control instructions and trigger the FPGA to perform digital-to-analog conversion to ensure that the voltage regulation process has low latency characteristics.

[0122] During the startup phase, the ranging device first obtains the target's position information through a pre-scan and estimates the target's distance range based on the pre-scan results. For example, for close-range targets within 20 meters, the highest driving voltage that may cause signal saturation is calculated as a reference value based on a preset reflectivity model. This reference value sends a control instruction to the FPGA via the MCU, which controls the digital-to-analog conversion module to output the corresponding driving voltage, causing the laser emission tube to start working at the critical saturation voltage. This collaborative mechanism allows the voltage loading process to be initialized within milliseconds without human intervention, effectively shortening the device's response time.

[0123] Compared to existing technologies, traditional ranging devices typically use a fixed drive voltage for startup. This can lead to multiple voltage adjustments due to signal saturation when encountering highly reflective and / or close-range targets. This embodiment, however, dynamically sets the reference voltage by pre-determining target distance, directly adjusting the initial voltage to near the theoretical saturation threshold. For example, for highly reflective targets like white walls, the reference voltage can be automatically lowered to 85% of the critical value. This proactive pre-adjustment reduces the number of voltage calibrations from an average of 5-7 to 1-2, significantly improving ranging efficiency.

[0124] Through the above-mentioned technical means, this embodiment effectively solves the problem of signal saturation caused by high-reflectivity and close-range targets. By combining distance prediction with a preset threshold voltage, the ranging device can obtain a valid echo signal from the first sampling. The dynamic reference voltage loading mechanism avoids the delay caused by the trial-and-error adjustment in traditional methods, maintaining stable ranging accuracy and response speed even in complex reflective environments.

[0125] It should be noted that the distance measuring device in this embodiment includes an avalanche diode.

[0126] Based on the above circuit structure, refer to Figure 8Another embodiment of the present invention provides a distance measurement method based on the above Figure 1 In the embodiment shown, the obtaining of current echo data includes steps S110-S120, wherein:

[0127] S110, receiving the laser pulse reflected by the target through the avalanche diode and generating a corresponding echo electrical signal;

[0128] S120 , amplifying the echo electrical signal and performing digital conversion to generate the current echo data.

[0129] Among them, an avalanche diode refers to a semiconductor device that uses the avalanche breakdown effect to convert optical signals into electrical signals. It can be manufactured using silicon-based or germanium-based materials, and the output current is enhanced by the multiplication effect under weak optical signals. The high sensitivity of this device helps to capture effective echo signals in low-reflectivity or long-distance scenarios. The echo electrical signal refers to the analog electrical signal output by the avalanche diode. It can be converted from current to voltage by a transimpedance amplifier to form a voltage waveform corresponding to the light intensity. Amplification refers to the gain processing of the electrical signal, which can be achieved using a multi-stage operational amplifier circuit. The signal is adapted to the input range of the subsequent analog-to-digital converter by adjusting the amplification factor. Digital conversion refers to the conversion of analog signals into digital signals. It can be achieved using an analog-to-digital converter, for example, by combining a sample-and-hold circuit with a successive approximation converter, so that the echo signal can be analyzed by a digital processor.

[0130] During ranging, an avalanche diode receives laser pulses reflected from a target, generating a weak current signal proportional to the light intensity. This current signal is converted to a voltage by a transimpedance amplifier and then adjusted to the valid input range of an analog-to-digital converter through a multi-stage amplification circuit. The analog-to-digital converter quantizes the analog voltage at a fixed sampling rate, generating digital echo data containing time and amplitude information. The high gain characteristics of the avalanche diode enable effective echo signal extraction even in the presence of low target reflectivity or strong ambient light interference, preventing ranging failures caused by signal loss. The digitized data can be directly used for waveform state analysis. For example, by detecting the number of consecutive high levels in the digital signal, saturation can be determined, providing a basis for subsequent power adjustments.

[0131] Compared with existing technologies, traditional ranging devices typically use ordinary photodiodes as receiving elements, which have low sensitivity and require complex external compensation circuits in low-light scenarios, resulting in a decrease in the response speed of the ranging device. This embodiment, however, uses an avalanche diode as the core receiving device, directly boosting signal strength through the internal carrier multiplication effect, avoiding the noise and delay introduced by external compensation circuits. Furthermore, the position of the analog-to-digital converter in the signal chain has been optimized to enable immediate digitization of the signal after amplification, preventing interference with the analog signal during long-distance transmission and ensuring the integrity of the echo data.

[0132] Through the aforementioned technical means, this embodiment can stably acquire echo signals with a high signal-to-noise ratio in scenarios with targets made of materials with varying reflectivity, effectively addressing signal saturation or attenuation caused by variations in target surface properties. The synergistic effect of the avalanche diode and digital conversion enables the ranging device to accurately capture the arrival time of laser pulses even in complex optical environments, thereby improving the reliability of distance calculations.

[0133] The present invention also proposes a distance measuring device, which includes: the distance measuring device includes: a memory, a processor, and a distance measuring program stored in the memory and executable on the processor, wherein the distance measuring program is configured to implement the distance measuring method described above.

[0134] It is worth noting that since the distance measuring device of the present invention is based on the above-mentioned distance measuring method, the embodiments of the distance measuring device of the present invention include all technical solutions of all embodiments of the above-mentioned distance measuring method, and the technical effects achieved are also exactly the same, which will not be repeated here.

[0135] The present invention further provides a distance measuring device, which includes the distance measuring apparatus described in the above embodiment.

[0136] It is worth noting that since the distance measuring device of the present invention is based on the above-mentioned distance measuring device, the embodiments of the distance measuring device of the present invention include all technical solutions of all embodiments of the above-mentioned distance measuring device, and the technical effects achieved are also exactly the same, which will not be repeated here.

[0137] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or system comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or system. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or system comprising the element.

[0138] The serial numbers of the above embodiments of the present invention are for description only and do not represent the advantages or disadvantages of the embodiments.

[0139] Through the above description of the embodiments, those skilled in the art will clearly understand that the methods of the above embodiments can be implemented using software plus the necessary general-purpose hardware platform. Of course, hardware can also be used, but in many cases the former is a more preferred implementation method. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, or optical disk) as described above and includes a number of instructions for enabling a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in various embodiments of the present invention.

[0140] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A distance measurement method, applied to a distance measurement device, wherein the distance measurement device includes a laser emitting tube, characterized in that: The ranging method includes: Get current echo data; Determining a waveform state corresponding to the echo data; Adjusting the emission power of the laser emitting tube according to the waveform state until the waveform state is in an unsaturated state; When the waveform is in an unsaturated state, determining a distance of a current test; The step of adjusting the emission power of the laser emitting tube according to the waveform state until the waveform state is in an unsaturated state includes: If the waveform state is a saturated state, reducing the driving voltage of the laser emitting tube according to a preset step size, wherein the preset step size is dynamically adjusted according to the target reflectivity or the ambient optical characteristics; Reacquiring echo data to determine a new waveform state of the echo data until the waveform state is in an unsaturated state; The step of adjusting the emission power of the laser emitting tube according to the waveform state until the waveform state is in an unsaturated state includes: If the waveform state is a saturation state, calculating a voltage difference between the current driving voltage and a theoretical saturation voltage corresponding to the target reflectivity or the ambient optical characteristic; Adjusting the driving voltage of the laser emitting tube to within a theoretical saturation voltage range according to the voltage difference, so that the waveform state is in an unsaturated state; Reacquire the echo data to determine the new waveform state of the echo data until the waveform state is in an unsaturated state Determining the waveform state corresponding to the echo data includes: Detecting a distribution condition of the echo data at an upper limit of a voltage range; If there are multiple echo data at the upper limit of the voltage range, determining that the waveform state is a saturation state; If the voltage of the echo data does not reach the upper limit of the voltage range, it is determined that the waveform state is an unsaturated state.

2. The distance measurement method according to claim 1, wherein: If the waveform state is a saturation state, reducing the driving voltage of the laser emitting tube according to a preset step size includes: If the waveform state is a saturation state, calculating a voltage difference between the current driving voltage and a theoretical saturation voltage corresponding to the target reflectivity or the ambient optical characteristic; According to the voltage difference and the preset step size, the driving voltage of the laser emitting tube is gradually reduced; The reacquiring echo data to determine a new waveform state of the echo data until the waveform state is in an unsaturated state includes: After adjusting the driving voltage of the laser emitting tube, reacquiring echo data to determine a new waveform state of the echo data; If the waveform is in a saturated state, the driving voltage of the laser emitting tube is reduced again.

3. The distance measurement method according to claim 1, wherein: The step of determining the distance of the current test when the waveform state is in an unsaturated state includes: When the waveform state is in an unsaturated state, a time difference between laser pulse emission and echo signal reception is recorded by a timer; The distance of the current test corresponding to the time difference is calculated according to the speed of light distance formula.

4. The distance measurement method according to claim 1, wherein: The ranging method further includes: Get the distance prediction value of the target point to be measured; Setting a reference voltage according to the distance prediction value, wherein the reference voltage is a critical saturation voltage set according to a maximum reflectivity target; The reference voltage is set as the upper limit of the voltage range.

5. The distance measurement method according to claim 1, wherein: The distance measuring device includes an avalanche diode; The obtaining of current echo data comprises: The laser pulse reflected by the target is received by the avalanche diode, generating a corresponding echo electrical signal; After the echo electrical signal is amplified, it is digitally converted to generate the current echo data.

6. A distance measuring device, characterized in that: The distance measuring device includes: a memory, a processor, and a distance measuring program stored in the memory and executable on the processor, wherein the distance measuring program is configured to implement the distance measuring method according to any one of claims 1 to 5.

7. A distance measuring device, characterized in that: Comprising the distance measuring device as claimed in claim 6.

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