Laser ranging device and signal processing method and system thereof

Abstract

The invention relates to a laser ranging device and a signal processing method and system thereof, and the method comprises the steps: enabling a laser transmitter to transmit an initial laser signal to a target object; then acquiring an unsaturated echo signal reflected by the target object and received by the optical detector, and filtering the unsaturated echo signal to obtain a direct-current distance measurement signal, so that stray light can be effectively filtered, and the accuracy of a distance measurement result is improved; and whether the intensity of the loss of the unsaturated echo signal affects the preset distance measurement precision is judged, and the transmitting power of the laser transmitter is adjusted when the intensity of the loss of the unsaturated echo signal affects the preset distance measurement precision until the intensity of the loss of the unsaturated echo signal does not affect the preset distance measurement precision, so that the accuracy of the distance measurement result can be further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of laser ranging, and particularly to a laser ranging device, a signal processing method thereof, and a system. Background Art

[0002] A coaxial laser rangefinder refers to a ranging device in which the transmitting optical path and the receiving optical path are arranged on the same axis, and has advantages such as high ranging accuracy, small volume, and light weight. As Figure 1 shown, the laser transmitter 11 of the coaxial laser rangefinder emits laser light, the focusing lens 12 focuses the laser light so that it is emitted without obstruction through the small hole of the perforated mirror 13, and then it is collimated and emitted without obstruction through the central region of the lens 14, and the laser light hits the target object 15. The focus of the non-central region of the lens 14 is on the photosensitive surface of the detector 16. Thus, the laser light reflected from the target object 15 is received by the detector 16 after passing through the lens 14. However, there is stray light inside the lens 14. In particular, the side of the lens 14 facing the perforated mirror 13 will reflect part of the emitted laser light back, forming stray light and being received by the detector 16. The stray light signal will interfere with the effective echo signal and reduce the accuracy of the measurement result. Summary of the Invention

[0003] Based on this, in view of the above technical problems, it is necessary to provide a laser ranging device and a signal processing system that can effectively filter out stray light and improve the accuracy of the measurement result.

[0004] In a first aspect, the present invention provides a signal processing method for a laser ranging device, including:

[0005] Causing a laser transmitter to emit an initial laser signal to a target object;

[0006] Obtaining an unsaturated echo signal reflected from the target object received by a photodetector, and filtering the unsaturated echo signal to obtain a DC ranging signal;

[0007] Obtaining a first intensity loss value of the unsaturated echo signal, and judging whether the intensity loss of the unsaturated echo signal affects a preset ranging accuracy;

[0008] If it does not affect, calculating the distance of the target object according to the DC ranging signal;

[0009] If it affects, calculating an unsaturated DC signal intensity loss value, and adjusting the emission power of the laser transmitter according to the unsaturated DC signal intensity loss value until the intensity loss of the unsaturated echo signal does not affect the preset ranging accuracy.

[0010] Further, the step of obtaining the unsaturated echo signal reflected from the target object received by the photodetector includes:

[0011] Obtain the original laser signal reflected by the target received by the photodetector;

[0012] Determine whether the intensity value of the original laser signal is less than a preset threshold. If so, use the original laser signal with an intensity value less than the preset threshold as the non-saturated echo signal. If not, adjust the emission power of the laser emitter until the intensity value of the original laser signal is less than the preset threshold.

[0013] Further, the steps of obtaining the first intensity loss value of the non-saturated echo signal and determining whether the intensity loss of the non-saturated echo signal affects the preset ranging accuracy according to the first intensity loss value include:

[0014] Obtain the intensity value of the non-saturated echo signal and the intensity value of the DC ranging signal;

[0015] Calculate the difference between the intensity value of the non-saturated echo signal and the intensity value of the DC ranging signal, so as to obtain the first intensity loss value of the non-saturated echo signal;

[0016] According to the mapping relationship, determine whether the ranging accuracy corresponding to the first intensity loss value is within the preset accuracy range. If so, it is determined that the intensity loss of the non-saturated echo signal does not affect the preset ranging accuracy. If not, it is determined that the intensity loss of the non-saturated echo signal affects the preset ranging accuracy.

[0017] Further, the steps of calculating the intensity loss value of the non-saturated DC signal and adjusting the emission power of the laser emitter according to the intensity loss value of the non-saturated DC signal until the intensity loss of the non-saturated echo signal does not affect the preset ranging accuracy include:

[0018] Obtain the intensity value of the initial laser signal and the intensity value of the DC ranging signal;

[0019] Calculate the difference between the intensity value of the initial laser signal and the intensity value of the DC ranging signal to obtain the intensity loss value of the non-saturated DC signal;

[0020] According to the intensity loss value of the non-saturated DC signal, determine the power value step size, and adjust the emission power of the laser emitter according to the power value step size until the intensity loss of the non-saturated echo signal does not affect the preset ranging accuracy.

[0021] Further, after filtering the non-saturated echo signal to obtain the DC ranging signal, the following steps are also included:

[0022] Obtain the preset stray light signal intensity value corresponding to the current emission power of the laser emitter;

[0023] Subtract the intensity value of the stray light signal from the intensity value of the DC ranging signal;

[0024] Calculating the distance to the target object based on the DC ranging signal includes: calculating the distance to the target object based on the DC ranging signal after subtracting the intensity value of the stray light signal.

[0025] Further, after filtering the non-saturated echo signal to obtain the DC ranging signal, the following steps are also included: performing an amplification process on the DC ranging signal; or

[0026] Before filtering the non-saturated echo signal, the following steps are also included: performing an amplification process on the non-saturated echo signal; the step of filtering the non-saturated echo signal includes: filtering the amplified non-saturated echo signal.

[0027] In a second aspect, the present invention also provides a signal processing system for a laser ranging device, including:

[0028] A driving module for driving a laser emitter to emit an initial laser signal to a target object;

[0029] A receiving module for acquiring the non-saturated echo signal reflected back from the target object received by a photodetector, and filtering the non-saturated echo signal to obtain a DC ranging signal;

[0030] A judging module for acquiring a first intensity loss value of the non-saturated echo signal, and judging whether the intensity loss of the non-saturated echo signal affects a preset ranging accuracy according to the first intensity loss value;

[0031] A calculating module for calculating the distance to the target object according to the DC ranging signal when the intensity loss of the non-saturated echo signal does not affect the preset ranging accuracy;

[0032] An adjusting module for calculating a non-saturated DC signal intensity loss value when the intensity loss of the non-saturated echo signal affects the preset ranging accuracy, and controlling the driving module to adjust the emission power of the laser emitter according to the non-saturated DC signal intensity loss value until the intensity loss of the non-saturated echo signal does not affect the preset ranging accuracy.

[0033] Further, the judging module is specifically configured to:

[0034] Acquire the intensity value of the non-saturated echo signal and the intensity value of the DC ranging signal;

[0035] Calculate the difference between the intensity value of the non-saturated echo signal and the intensity value of the DC ranging signal, so as to obtain the first intensity loss value of the non-saturated echo signal;

[0036] According to the mapping relationship, determine whether the ranging accuracy corresponding to the first intensity loss value is within the preset accuracy range. If so, it is determined that the intensity loss of the non-saturated echo signal does not affect the preset ranging accuracy. If not, it is determined that the intensity loss of the non-saturated echo signal affects the preset ranging accuracy.

[0037] Further, it further includes a processing module, and the processing module is used to obtain the preset stray light signal intensity value corresponding to the current emission power of the laser emitter, and subtract the intensity value of the stray light signal from the intensity value of the DC ranging signal;

[0038] The calculation module is used to calculate the distance of the target object according to the DC ranging signal after subtracting the intensity value of the stray light signal.

[0039] In a third aspect, the present invention further provides a laser ranging device, including a laser emitter, a photodetector, and the signal processing system described above.

[0040] The above introduces a signal processing method of a laser ranging device. By filtering the non-saturated echo signal reflected by the target object, stray light can be effectively filtered, improving the accuracy of the ranging result. And by judging whether the intensity loss of the non-saturated echo signal affects the preset ranging accuracy, when it affects, the emission power of the laser emitter is adjusted until the intensity loss of the non-saturated echo signal does not affect the preset ranging accuracy, thereby further improving the accuracy of the ranging result. Description of the Drawings

[0041] Figure 1 is a schematic structural diagram of a coaxial laser rangefinder in the prior art;

[0042] Figure 2 is a flowchart of the signal processing method provided by the present invention;

[0043] Figure 3 is a waveform diagram of the echo signal with flat-top distortion generated by the coaxial laser rangefinder in the prior art;

[0044] Figure 4 is a waveform comparison diagram of the echo signal before and after reducing the emission power in the signal processing method provided by the present invention;

[0045] Figure 5 is another waveform comparison diagram of the echo signal before and after reducing the emission power in the signal processing method provided by the present invention;

[0046] Figure 6 is a waveform comparison diagram of the echo signal before and after reducing the emission power and after subtracting the calibrated stray light signal in the signal processing method provided by the present invention;

[0047] Figure 7It is a schematic structural diagram of the signal processing system provided by the present invention;

[0048] Figure 8 It is another schematic structural diagram of the signal processing system provided by the present invention. Specific embodiments

[0049] In order to make the objectives, technical solutions and advantages 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 only used to explain the present invention and are not used to limit the present invention.

[0050] Refer to Figure 2 , the embodiments of the present invention provide a signal processing method for a laser ranging device, including the following steps:

[0051] Step S101: Make the laser transmitter emit an initial laser signal to the target.

[0052] The laser transmitter can be a pulsed laser transmitter. By providing a driving voltage to the laser transmitter, the laser transmitter emits periodic pulsed laser, such as periodically emitting initial pulsed laser signals with high, medium, and low powers, to detect all targets in the application scenario.

[0053] Step S102: Obtain the non-saturated echo signal reflected by the target received by the photodetector, and filter the non-saturated echo signal to obtain a DC ranging signal.

[0054] As Figure 3 shown, laser emission requires high-voltage drive, and the magnitude of the drive voltage affects the intensity of the emitted laser. The greater the drive voltage, the stronger the laser intensity. When a sufficiently strong laser is emitted and reflected by the target, the echo signal will also be very strong. If the intensity of the echo signal exceeds the reception threshold of the photodetector at this time, there will be a signal flat-top distortion phenomenon as shown in Figure 3 shown, that is, the signal oversaturation problem, resulting in difficulty in positioning the peak of the echo signal, making it impossible to obtain the ranging value or having a large error. In the present invention, the photodetector obtains at least one full-peak signal of pulsed laser corresponding to the emission power reflected by the target within the application range, that is, the non-saturated echo signal. By using the non-saturated echo signal for ranging, the accuracy of the measurement result can be improved. Among them, the emission power of the laser transmitter can be adjusted so that the echo signal reflected by the target is a non-saturated echo signal.

[0055] More specifically, the steps of obtaining the unsaturated echo signal reflected by the target object received by the photodetector include: obtaining the original laser signal reflected by the target object received by the photodetector; determining whether the intensity value of the original laser signal is less than a preset threshold. If so, the original laser signal with an intensity value less than the preset threshold is used as the unsaturated echo signal. If not, the emission power of the laser emitter is adjusted until the intensity value of the original laser signal is less than the preset threshold. The target object reflects the initial pulse laser signals with high, medium, and low powers, so that the photodetector receives a signal group containing three original laser signals. By determining whether the intensity value of the received original laser signal is less than the preset threshold, which is the reception threshold of the photodetector. If it is less, it means that the original laser signal has not undergone flat-top distortion and is a full-peak signal, that is, an unsaturated signal. At this time, the original laser signal is the unsaturated echo signal. If it is not less, it means that the original laser signal has undergone flat-top distortion. This distortion phenomenon may be caused by too high intensity of the emitted laser. As Figure 4 shown, at this time, the driving voltage of the laser emitter can be reduced to reduce the emission power, thereby reducing the intensity of the emitted laser until the intensity value of the original laser signal received by the photodetector is less than the preset threshold, and thus the unsaturated echo signal can be obtained. Among them Figure 4 in the waveform shown, a1 represents the waveform of the original laser signal with flat-top distortion, and b1 represents the waveform of the unsaturated echo signal after reducing the emission power. Among them, as long as there is at least one unsaturated echo signal among the three original laser signals, there is no need to adjust the emission power or stop adjusting the emission power.

[0056] In addition, when the stray light signal is strong and the stray light signal submerges the echo signal, the flat-top distortion of the original laser signal may be caused by the large intensity of the stray light. As Figure 5 shown, by reducing the emission power of the laser emitter, not only can the flat-top distortion of the echo signal reflected by the target object be avoided, but also the pulse width of the stray light signal can be made narrower, so as to achieve the effect of separating the stray light signal and the echo signal reflected by the target object, which is beneficial to filtering out the stray light during subsequent filtering operations. Among them Figure 5 in the waveform shown, a1 represents the waveform of the original laser signal with flat-top distortion, and b1 represents the waveform of the unsaturated echo signal after reducing the emission power. Among them, because the stray light signal is strong, there will still be a flat-top distorted stray light signal in the b1 waveform.

[0057] After obtaining the unsaturated echo signal reflected by the target object, the unsaturated echo signal is filtered.

[0058] As Figure 1As shown, the stray light caused by the internal lens reflection in the emission system of the laser ranging device will be received by the photodetector, and these stray light signals exhibit the characteristics of alternating current signals; while the laser returned by the target object is received by the photodetector and exhibits the characteristics of direct current signals. Since the stray light signals are mainly formed by the reflection of the lenses in the emission barrel and there is a frequency difference from the echo signals reflected by external target objects, the present invention can effectively filter out the stray light by filtering the non-saturated echo signals.

[0059] Step S103: Obtain the first intensity loss value of the non-saturated echo signal, and determine whether the intensity loss of the non-saturated echo signal affects the preset ranging accuracy according to the first intensity loss value.

[0060] Among them, the preset ranging accuracy can be the ranging accuracy of the laser ranging device, that is, after filtering the non-saturated echo signal, further determine whether the intensity loss of the filtered non-saturated echo signal will affect the ranging accuracy. Specifically, step S103 can include the following steps: obtain the intensity value of the non-saturated echo signal and the intensity value of the direct current ranging signal; calculate the difference between the intensity value of the non-saturated echo signal and the intensity value of the direct current ranging signal, so as to obtain the first intensity loss value of the non-saturated echo signal; according to the mapping relationship, determine whether the ranging accuracy corresponding to the first intensity loss value is within the preset accuracy range. If so, it is determined that the intensity loss of the non-saturated echo signal does not affect the preset ranging accuracy. If not, it is determined that the intensity loss of the non-saturated echo signal affects the preset ranging accuracy.

[0061] Among them, the intensity value of the non-saturated echo signal is the intensity value before filtering the non-saturated echo signal, and the intensity value of the direct current ranging signal is the intensity value after filtering the non-saturated echo signal. By calculating the difference between the two, the intensity loss value before and after filtering the non-saturated echo signal can be obtained. In addition, before step S103, the mapping relationship between different signal intensity loss values and different ranging accuracies can be preset. For example, when the intensity loss value is A1, the corresponding ranging accuracy is B1; when the intensity loss value is A2, the corresponding ranging accuracy is B2. The preset accuracy range can be set according to the preset ranging accuracy, that is, the ranging accuracy of the laser ranging device. For example, if the preset ranging accuracy is B3, the preset accuracy range can be set to (B3 - b1) to (B3 + b1), or (B3 - b1) to (B3 + b2). In order to improve the accuracy of the ranging result, the values of b1 and b1 should be as small as possible. Thus, after obtaining the first intensity loss value of the non-saturated echo signal, the ranging accuracy corresponding to the first intensity loss value can be determined according to the mapping relationship, and then it is determined whether the corresponding ranging accuracy is within the preset accuracy range. If it is within the preset accuracy range, it is determined that the intensity loss of the non-saturated echo signal does not affect the preset ranging accuracy. If it is not within the preset accuracy range, it is determined that the intensity loss of the non-saturated echo signal affects the preset ranging accuracy.

[0062] Step S104: If there is no impact, calculate the distance to the target based on the DC ranging signal; if there is an impact, calculate the intensity loss value of the non-saturated DC signal, and adjust the transmission power of the laser emitter according to the intensity loss value of the non-saturated DC signal until the intensity loss of the non-saturated echo signal does not affect the preset ranging accuracy.

[0063] When the intensity loss of the filtered non-saturated echo signal does not affect the preset ranging accuracy, the distance to the target can be directly calculated using the DC ranging signal at this time.

[0064] When the intensity loss of the filtered non-saturated echo signal affects the preset ranging accuracy, if the distance to the target is calculated using the DC ranging signal obtained after filtering at this time, the ranging result error may be relatively large. Therefore, readjust the transmission power. Each time the transmission power is adjusted, obtain the non-saturated echo signal again until it is determined that the intensity loss of the non-saturated echo signal does not affect the preset ranging accuracy.

[0065] Specifically, calculating the intensity loss value of the non-saturated DC signal and adjusting the transmission power of the laser emitter according to the intensity loss value of the non-saturated DC signal includes the following steps: obtaining the intensity value of the initial laser signal and the intensity value of the DC ranging signal; calculating the difference between the intensity value of the initial laser signal and the intensity value of the DC ranging signal to obtain the intensity loss value of the non-saturated DC signal; determining the power value step size according to the intensity loss value of the non-saturated DC signal, and adjusting the transmission power of the laser emitter according to the power value step size until the intensity loss of the non-saturated echo signal does not affect the preset ranging accuracy.

[0066] Among them, before step S104, the mapping relationship between the intensity loss value of the non-saturated DC signal and the power value step size can be preset. For example, when the intensity loss value of the non-saturated DC signal is C1, the corresponding power value step size is P1; when the intensity loss value of the non-saturated DC signal is C2, the corresponding power value step size is P2. After calculating the intensity loss value of the non-saturated DC signal, the corresponding power value step size can be determined according to the mapping relationship, and then the transmission power of the laser emitter is adjusted according to the determined power value step size until it is determined that the intensity loss of the non-saturated echo signal does not affect the preset ranging accuracy. Thus, the optimal light output power can be obtained, which is beneficial to improving the ranging accuracy.

[0067] The signal processing method of the embodiment of the present invention can effectively filter out stray light by filtering the non-saturated echo signal, and can solve the problem of signal flat-top distortion by adjusting the transmission power, thereby eliminating the blind area problem caused by stray light in the coaxial ranging system.

[0068] In an embodiment of the present invention, after filtering the non-saturated echo signal to obtain a DC ranging signal, the following steps are further included: amplifying the DC ranging signal, and using the amplified DC ranging signal to calculate the distance of the target object when calculating the distance of the target object. Alternatively, before filtering the non-saturated echo signal, the following steps are further included: amplifying the non-saturated echo signal; the step of filtering the non-saturated echo signal includes: filtering the amplified non-saturated echo signal. Among them, it can be determined whether to filter first and then amplify or amplify first and then filter according to the target object in the application scenario.

[0069] For example, if the application scenario is mainly for target objects with weak reflectivity, the non-saturated echo signal can be amplified first and then filtered; if the application scenario is mainly for target objects with strong reflectivity, the non-saturated echo signal can be filtered first and then amplified.

[0070] When the echo signal is made non-flat-topped through power adjustment and the non-saturated echo signal is filtered, affected by the signal amplification process, the effect of filtering may be reduced, resulting in the possible existence of stray light in the DC ranging signal, causing the waveform of the DC ranging signal to change, and the reception time is determined by the waveform. For example, for the ranging calculation method of the time-of-flight method: D = Ct / 2, where D is the ranging value, C is the speed of light, and t is the time from transmission to reception. Among them, the speed of light is fixed, and the transmission time is determined by the hardware performance. Therefore, the factor determining the ranging accuracy is the reception time, and the reception time is determined according to the waveform of the echo signal received by the photodetector. For example, the time point corresponding to the center point or peak point of the waveform is used as the reception time. Therefore, when the waveform of the DC ranging signal changes, it will affect the determination of the reception time, possibly resulting in a large error. In an embodiment of the present invention, the stray light is filtered by means of stray light calibration, whereby a better signal waveform can be obtained, thereby improving the determination accuracy of the reception time and improving the accuracy of the ranging result.

[0071] Specifically, in an embodiment of the present invention, after filtering the non-saturated echo signal to obtain a DC ranging signal, the following steps are further included: obtaining a preset stray light signal intensity value corresponding to the current emission power of the laser emitter; subtracting the intensity value of the stray light signal from the intensity value of the DC ranging signal.

[0072] Calculating the distance of the target object according to the DC ranging signal includes: calculating the distance of the target object according to the DC ranging signal after subtracting the intensity value of the stray light signal.

[0073] The value of the stray light signal is also fixed for a fixed transmission power. By pre-calibrating the corresponding stray light signal intensity values for different transmission powers one by one, that is, by presetting the stray light signal intensity values corresponding to different transmission powers of the laser transmitter, the stray light signal intensity value corresponding to the current transmission power can be determined according to this corresponding relationship. Then, subtract the stray light signal intensity value from the intensity value of the DC ranging signal obtained after filtering, as Figure 6 shown. Thus, the influence of stray light can be reduced, making the waveform of the DC ranging signal more accurate, and thereby improving the determination accuracy of the reception time. Among them Figure 6 In the waveform shown, a1 represents the original laser signal waveform with flat-top distortion, b1 represents the non-saturated echo signal waveform after reducing the transmission power, and c1 represents the DC ranging signal waveform after reducing the transmission power and subtracting the calibrated stray light signal.

[0074] Referring to Figure 7 , the embodiment of the present invention further provides a signal processing system 700 for a laser ranging device. The signal processing system 700 is used to execute the steps in the signal processing method described in the above embodiment. The signal processing system 700 includes a driving module 701, a receiving module 702, a judging module 703, a calculating module 704, and an adjusting module 705.

[0075] Among them, the driving module 701 is used to drive the laser transmitter 50 to emit an initial laser signal to the target 51. Further, the driving module 701 may include a voltage regulating circuit 7011 and a voltage dividing circuit 7012. The voltage regulating circuit 7011 can be implemented by a boost chip and is used to convert the low voltage supplied by the power supply 52 into a high voltage pulse after receiving the start pulse sent by the MCU to drive the laser transmitter 50.

[0076] The voltage dividing circuit 7012 can be implemented by a multi-stage digital potentiometer and can numerically control its own resistance value to divide the fixed high voltage value generated by the voltage regulating circuit 7011: U O = R * U All / R All , where U0 represents the voltage value after voltage division, U All represents the high voltage value generated by the voltage regulating circuit 7011, R represents the voltage dividing resistance value of the digital potentiometer, and R All represents the total resistance value of the digital potentiometer. Through the action of the voltage dividing circuit 7012, the high voltage pulse generated by the voltage regulating circuit 7011 can be reduced, thereby reducing the driving voltage of the laser transmitter 50 to reduce the intensity of the emitted laser.

[0077] The receiving module 702 is used to obtain the non-saturated echo signal reflected back by the target object 51 received by the photodetector 53, and filter the non-saturated echo signal to obtain a DC ranging signal. Specifically, the photodetector 52 receives the original laser signal reflected back by the target object 51. The photodetector 52 can be a photodiode. The receiving module 702 is used to obtain the original laser signal and determine whether the intensity value of the original laser signal is less than a preset threshold. If so, the original laser signal with an intensity value less than the preset threshold is used as the non-saturated echo signal. If not, the adjustment module 705 controls the voltage dividing circuit 7012 to perform voltage division to reduce the emission power of the laser transmitter 50 until the intensity value of the original laser signal is less than the preset threshold. By reducing the emission power of the laser transmitter 50, the intensity of the emitted laser can be reduced, thereby reducing the intensity of the reflected echo signal. When the intensity value of the echo signal is less than the preset threshold (i.e., the acceptance threshold of the photodetector 52), the non-saturated echo signal can be obtained.

[0078] Among them, the receiving module 702 includes a filtering circuit 7021 for filtering the non-saturated echo signal. The filtering circuit 7021 can be implemented by capacitors. For example, the filtering circuit 7021 may include a group of capacitors with controllable switches for filtering different DC signals and AC signals. By selecting an efficient capacitor model, the filtering system can be determined. When the non-saturated echo signal with DC characteristics and the stray light with AC characteristics pass through the filtering circuit 7021, the non-saturated echo signal with DC characteristics passes through, thereby effectively filtering out the stray light.

[0079] The judgment module 703 is used to obtain the first intensity loss value of the non-saturated echo signal and judge whether the intensity loss of the non-saturated echo signal affects the preset ranging accuracy according to the first intensity loss value. Specifically, the judgment module 703 is used to obtain the intensity value of the non-saturated echo signal and the intensity value of the DC ranging signal, and then calculate the difference between the intensity value of the non-saturated echo signal and the intensity value of the DC ranging signal to obtain the first intensity loss value of the non-saturated echo signal. Then, according to the mapping relationship, judge whether the ranging accuracy corresponding to the first intensity loss value is within the preset accuracy range. If so, judge that the intensity loss of the non-saturated echo signal does not affect the preset ranging accuracy. If not, judge that the intensity loss of the non-saturated echo signal affects the preset ranging accuracy.

[0080] The calculation module 704 is used to calculate the target object distance according to the DC ranging signal when the intensity loss of the non-saturated echo signal does not affect the preset ranging accuracy.

[0081] The adjustment module 705 is used to calculate the intensity loss value of the non-saturated DC signal when the intensity loss of the non-saturated echo signal affects the preset ranging accuracy, and control the driving module to adjust the transmission power of the laser transmitter 50 according to the intensity loss value of the non-saturated DC signal. Specifically, the voltage division circuit 7012 is controlled to perform voltage division to adjust the transmission power of the laser transmitter 50 until the intensity loss of the non-saturated echo signal does not affect the preset ranging accuracy.

[0082] In the embodiment of the present invention, the receiving module 702 may further include an amplifying circuit 7022. The amplifying circuit 7022 is used to amplify the DC ranging signal after the filtering circuit 7021 filters the non-saturated echo signal, and the calculation module 704 uses the amplified DC ranging signal to calculate the distance of the target object. Alternatively, the amplifying circuit 7022 is used to amplify the non-saturated echo signal before filtering the non-saturated echo signal, and then the filtering circuit 7021 filters the amplified non-saturated echo signal. It can be determined whether to filter first and then amplify or amplify first and then filter according to the target object in the application scenario.

[0083] Further, as Figure 8 shown, the signal processing system 700 may further include a processing module 706. The processing module 706 is used to obtain the preset stray light signal intensity value corresponding to the current transmission power of the laser transmitter 50, and subtract the intensity value of the stray light signal from the intensity value of the DC ranging signal. The calculation module 704 is used to calculate the distance of the target object according to the DC ranging signal after subtracting the intensity value of the stray light signal.

[0084] The embodiment of the present invention further provides a laser ranging device, including a laser transmitter, a photodetector, and the signal processing system described in the above embodiment.

[0085] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0086] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A signal processing method for a laser ranging device, characterized in that Including: Making a laser transmitter emit an initial laser signal to a target object; Obtaining an unsaturated echo signal reflected by the target object received by a photodetector, and filtering the unsaturated echo signal to obtain a DC ranging signal; Obtaining a first intensity loss value of the unsaturated echo signal, and judging whether the intensity loss of the unsaturated echo signal affects a preset ranging accuracy according to the first intensity loss value; If it does not affect, calculating the distance of the target object according to the DC ranging signal; If it affects, calculating an unsaturated DC signal intensity loss value, and adjusting the emission power of the laser transmitter according to the unsaturated DC signal intensity loss value until the intensity loss of the unsaturated echo signal does not affect the preset ranging accuracy.

2. The signal processing method according to claim 1, wherein The step of obtaining the unsaturated echo signal reflected by the target object received by the photodetector includes: Obtaining the original laser signal reflected by the target object received by the photodetector; Judging whether the intensity value of the original laser signal is less than a preset threshold value. If so, taking the original laser signal with the intensity value less than the preset threshold value as the unsaturated echo signal. If not, adjusting the emission power of the laser transmitter until the intensity value of the original laser signal is less than the preset threshold value.

3. The signal processing method according to claim 1, wherein The step of obtaining the first intensity loss value of the unsaturated echo signal, and judging whether the intensity loss of the unsaturated echo signal affects the preset ranging accuracy according to the first intensity loss value includes: Obtaining the intensity value of the unsaturated echo signal and the intensity value of the DC ranging signal; Calculating the difference between the intensity value of the unsaturated echo signal and the intensity value of the DC ranging signal, so as to obtain the first intensity loss value of the unsaturated echo signal; According to the mapping relationship, judging whether the ranging accuracy corresponding to the first intensity loss value is within the preset accuracy range. If so, judging that the intensity loss of the unsaturated echo signal does not affect the preset ranging accuracy. If not, judging that the intensity loss of the unsaturated echo signal affects the preset ranging accuracy.

4. The signal processing method according to claim 3, characterized in that The step of calculating the unsaturated DC signal intensity loss value, and adjusting the emission power of the laser transmitter according to the unsaturated DC signal intensity loss value until the intensity loss of the unsaturated echo signal does not affect the preset ranging accuracy includes: Obtaining the intensity value of the initial laser signal and the intensity value of the DC ranging signal; Calculating the difference between the intensity value of the initial laser signal and the intensity value of the DC ranging signal to obtain the unsaturated DC signal intensity loss value; According to the unsaturated DC signal intensity loss value, determining a power value step size, and adjusting the emission power of the laser transmitter according to the power value step size until the intensity loss of the unsaturated echo signal does not affect the preset ranging accuracy.

5. The signal processing method according to claim 1, wherein After filtering the unsaturated echo signal to obtain a DC ranging signal, the following steps are further included: Obtaining a preset stray light signal intensity value corresponding to the current emission power of the laser transmitter; Subtracting the intensity value of the stray light signal from the intensity value of the DC ranging signal; The calculating the distance of the target object according to the DC ranging signal includes: calculating the distance of the target object according to the DC ranging signal after subtracting the intensity value of the stray light signal.

6. The signal processing method according to claim 1, wherein After filtering the non-saturated echo signal to obtain a DC ranging signal, the following steps are further included: amplifying the DC ranging signal; or Before filtering the non-saturated echo signal, the following steps are further included: amplifying the non-saturated echo signal; the step of filtering the non-saturated echo signal includes: filtering the amplified non-saturated echo signal.

7. A signal processing system for a laser ranging device, characterized in that, Including: A driving module for driving a laser transmitter to emit an initial laser signal to a target; A receiving module for acquiring the non-saturated echo signal reflected by the target received by a photodetector, and filtering the non-saturated echo signal to obtain a DC ranging signal; A judging module for acquiring a first intensity loss value of the non-saturated echo signal, and judging whether the intensity loss of the non-saturated echo signal affects a preset ranging accuracy according to the first intensity loss value; A calculating module for calculating the distance of the target according to the DC ranging signal when the intensity loss of the non-saturated echo signal does not affect the preset ranging accuracy; An adjusting module for calculating a non-saturated DC signal intensity loss value when the intensity loss of the non-saturated echo signal affects the preset ranging accuracy, and controlling the driving module to adjust the emission power of the laser transmitter according to the non-saturated DC signal intensity loss value until the intensity loss of the non-saturated echo signal does not affect the preset ranging accuracy.

8. The signal processing system according to claim 7, wherein The judging module is specifically used for: acquiring the intensity value of the non-saturated echo signal and the intensity value of the DC ranging signal; calculating the difference between the intensity value of the non-saturated echo signal and the intensity value of the DC ranging signal, so as to obtain the first intensity loss value of the non-saturated echo signal; judging whether the ranging accuracy corresponding to the first intensity loss value is within a preset accuracy range according to the mapping relationship, if so, judging that the intensity loss of the non-saturated echo signal does not affect the preset ranging accuracy, if not, judging that the intensity loss of the non-saturated echo signal affects the preset ranging accuracy.

9. The signal processing system according to claim 7, wherein It further includes a processing module, and the processing module is used for acquiring a preset stray light signal intensity value corresponding to the current emission power of the laser transmitter, and subtracting the stray light signal intensity value from the intensity value of the DC ranging signal; The calculating module is used for calculating the distance of the target according to the DC ranging signal after subtracting the stray light signal intensity value.

10. A laser ranging device, characterized in that Including a laser transmitter, a photodetector and the signal processing system according to any one of claims 7-9.

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