Laser detection device

Abstract

The invention discloses a laser detection device, and relates to the technical field of laser detection. The laser detection device comprises a laser emitter, a laser detector and a laser echo signal processing circuit. The laser emitter emits laser to a target object. And the laser detector receives an echo signal reflected by the target object. The laser echo signal processing circuit carries out sampling processing on the echo signal. The laser echo signal processing circuit comprises a controller, a time-to-digital converter and a dynamic threshold generation circuit. The controller outputs a digital signal to the dynamic threshold generation circuit. The dynamic threshold generation circuit generates at least two analog threshold signals to the time-to-digital converter based on the digital signal. The time-to-digital converter performs sampling processing on the echo signal based on the threshold signal. Through the above mode, the echo signal can be sampled through the plurality of threshold signals, so that the sampling accuracy is improved, and the detection performance of the laser detection device is improved.

Description

Technical Field

[0001] The present application relates to the field of laser detection technology, and in particular to a laser detection device. Background Art

[0002] A laser detection device (such as a laser radar) is a system that emits a laser beam to detect the position, speed and other characteristic quantities of a target. Its working principle is to first emit a detection laser to the target, and then compare the received echo signal reflected from the target with the transmitted signal. After appropriate processing, relevant information about the target can be obtained, such as target distance, direction, altitude, speed, attitude, and even shape parameters.

[0003] At present, due to the hardware defects of the laser detection device, the sampling accuracy is poor, which in turn affects the detection performance of the laser detection device. Summary of the invention

[0004] The present application aims to provide a laser detection device that can sample and process echo signals through multiple threshold signals to improve sampling accuracy and thereby improve the detection performance of the laser detection device.

[0005] To achieve the above-mentioned objectives, in a first aspect, the present application provides a laser detection device, comprising: a laser transmitter for emitting a laser to a target object; a laser detector for receiving an echo signal reflected by the target object; a laser echo signal processing circuit for sampling and processing the echo signal; wherein the laser echo signal processing circuit comprises a controller, a time-to-digital converter and a dynamic threshold generation circuit, and the controller is electrically connected to the time-to-digital converter through the dynamic threshold generation circuit; the controller is used to output a digital signal to the dynamic threshold generation circuit; the dynamic threshold generation circuit is used to generate at least two analog threshold signals to the time-to-digital converter based on the digital signal; and the time-to-digital converter is used to sample and process the echo signal based on the threshold signal.

[0006] In an optional manner, the controller includes a first digital signal input and output port, and the digital signal output by the first digital signal input and output port includes a pulse width modulation signal; the dynamic threshold generation circuit includes a filter branch, the filter branch is electrically connected between the first digital signal input and output port and the time-to-digital converter, and the filter branch is used to receive the pulse width modulation signal and filter the pulse width modulation signal to generate a threshold signal; wherein, pulse width modulation signals with different duty cycles correspond to different threshold signals.

[0007] In an optional manner, the controller also includes a second digital signal input and output port, and the digital signal output by the second digital signal input and output port also includes a first high-level signal or a low-level signal; the dynamic threshold generation circuit also includes a summing branch, and the summing branch is electrically connected to the filtering branch, the second digital signal input and output port, and the time-to-digital converter, respectively, and the summing branch is used to sum the voltage signal obtained based on the first high-level signal or the low-level signal with the voltage signal obtained after filtering the pulse width modulation signal to generate a threshold signal; wherein, when the duty cycle of the pulse width modulation signal remains unchanged, the threshold signals corresponding to the first high-level signal and the low-level signal are different.

[0008] In an optional manner, the dynamic threshold generation circuit also includes a level conversion branch; the level conversion branch is connected between the second digital signal input and output port and the summing branch, and the level conversion branch is used to output a second high level signal or a low level signal based on the digital signal output by the second digital signal input and output port, wherein the voltages corresponding to the first high level signal and the second high level signal are different; the summing branch is also used to sum the voltage signal obtained based on the second high level signal or the low level signal with the voltage signal obtained after filtering the pulse width modulation signal to generate a threshold signal; wherein, when the duty cycle of the pulse width modulation signal remains unchanged, the threshold signals corresponding to the second high level signal and the low level signal are different.

[0009] In an optional manner, the filtering branch includes a first resistor and a first capacitor; the first resistor and the first capacitor are connected in series between the first digital signal input and output port and the ground, and the common node between the first resistor and the first capacitor is electrically connected to the time-to-digital converter.

[0010] In an optional manner, the summing branch includes a second resistor and a third resistor; the second resistor is electrically connected between the filtering branch and the time-to-digital converter, and the third resistor is electrically connected between the second digital signal input / output port and the time-to-digital converter.

[0011] In an optional manner, the level conversion branch includes a switch tube and a fourth resistor; the control end of the switch tube is electrically connected to the second digital signal input and output port, one end of the non-control end of the switch tube is electrically connected to the first end of the fourth resistor and the summing branch, the other end of the non-control end of the switch tube is grounded, and the second end of the fourth resistor inputs a voltage corresponding to a second high level signal; wherein, when the second digital signal input and output port outputs a first high level signal, the switch tube is turned on to output a low level signal; when the second digital signal input and output port outputs a low level signal, the switch tube is turned off to output a second high level signal.

[0012] In an optional manner, the time-to-digital converter is also used to output a pulse signal based on the sampling processing result, wherein the pulse signal includes at least one pulse, and each pulse is output when the echo signal is greater than or equal to the threshold signal; the controller is also used to adjust the digital signal based on the pulse signal to adjust the threshold signal output by the dynamic threshold generating circuit.

[0013] In an optional manner, the controller is further configured to adjust the digital signal to increase the threshold signal output by the dynamic threshold generation circuit if it is determined that a pulse having a pulse width greater than a preset width exists in the pulse signal.

[0014] In an optional manner, the controller is further configured to adjust the digital signal to reduce the threshold signal output by the dynamic threshold generation circuit if it is determined that a pulse having a pulse width less than a preset width exists in the pulse signal or no pulse is detected.

[0015] In an optional manner, the controller is further configured to adjust the digital signal to reduce the threshold signal output by the dynamic threshold generation circuit if only one pulse or no pulse is detected in a detection cycle after adjusting the digital signal to increase the threshold signal output by the dynamic threshold generation circuit. Optionally, the controller is further configured to switch to a high threshold if the detection pulse width exceeds a single pulse upper limit value after adjusting the digital signal to reduce the threshold signal generated by the dynamic threshold.

[0016] The beneficial effects of the present application are as follows: the laser detection device provided by the present application includes a laser transmitter, a laser detector and a laser echo signal processing circuit. When performing laser detection, the laser transmitter first emits a laser to the target object, and the laser detector then receives the echo signal reflected by the target object. Afterwards, the laser echo signal processing circuit samples and processes the echo signal. Among them, the laser echo signal processing circuit includes a controller, a time-to-digital converter and a dynamic threshold generation circuit. The controller outputs a digital signal to the dynamic threshold generation circuit, and the dynamic threshold generation circuit generates at least two analog threshold signals to the time-to-digital converter based on the digital signal, and the time-to-digital converter samples and processes the echo signal based on the threshold signal. During the processing, the echo signal is sampled and processed by multiple threshold signals, which can improve the sampling accuracy, thereby improving the detection performance of the laser detection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0018] Figure 1 A schematic diagram of the structure of a laser detection device provided in an embodiment of the present application;

[0019] Figure 2 A schematic diagram of various signals in a laser detection device provided in an embodiment of the present application;

[0020] Figure 3 A schematic diagram of various signals in a laser detection device provided in an embodiment of the present application;

[0021] Figure 4 A schematic diagram of the structure of a laser echo signal processing circuit provided in an embodiment of the present application;

[0022] Figure 5 A schematic diagram of the structure of a laser echo signal processing circuit provided in an embodiment of the present application;

[0023] Figure 6 For Figure 5 Schematic diagram of the circuit structure corresponding to the structure shown Figure 1 ;

[0024] Figure 7 For Figure 5 Schematic diagram of the circuit structure corresponding to the structure shown Figure 2 ;

[0025] Figure 8 A schematic diagram of the structure of a laser echo signal processing circuit provided in an embodiment of the present application;

[0026] Fig. 9 For Figure 8 Schematic diagram of the circuit structure corresponding to the structure shown. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0028] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of the laser detection device provided in the embodiment of the present application. Figure 1 As shown, the laser detection device 1 includes a laser transmitter 10 , a laser detector 20 and a laser echo signal processing circuit 30 .

[0029] In some embodiments, the laser detection device 1 can be a laser radar, or a signal processing device in a laser radar, or any device with ranging and speed measurement functions, such as a ranging and speed measurement sensor, a ranging and speedometer.

[0030] In this embodiment, the laser emitter 10 is used to emit a laser to the target object 2. The laser emitter 10 can emit a pulsed outgoing detection laser. The laser 10 can be, for example, a semiconductor light emitting diode LED (Light Emitting Diode), a semiconductor laser LD (Laser Diode), or a vertical cavity surface emitting laser VCSE1 (Vertical Cavity Surface Emitting Laser). The type of the laser emitter 10 can be set according to actual needs, and the embodiment of the present application does not impose any restrictions on the type of the laser emitter 10.

[0031] The laser detector 20 is used to receive the echo signal reflected by the target object 2. The signal generated by the laser emitted by the laser transmitter 10 and reflected on the target object 2 is the echo signal. The laser detector 20 receives the echo signal and obtains relevant information of the target object 2. Exemplarily, the flight time can be obtained by the emission time of the laser and the reception time of the echo signal, thereby obtaining the distance from the target object 2 to the location of the laser detection device 1. In some embodiments, the laser detector 20 includes a photodetector capable of detecting and converting optical signals into electrical signals.

[0032] The laser echo signal processing circuit 30 is used to sample and process the echo signal. In this embodiment, the laser echo signal processing circuit 30 and the laser detector 20 are two separate modules. In other embodiments, the laser echo signal processing circuit 30 may also be disposed in the laser detector 20, and the embodiment of the present application does not impose any specific limitation on this.

[0033] The laser echo signal processing circuit 30 includes a controller 31, a time-to-digital converter 32 and a dynamic threshold generating circuit 33. The controller 31 is electrically connected to the time-to-digital converter 32 via the dynamic threshold generating circuit 33.

[0034] Specifically, the controller 31 is used to output a digital signal to a dynamic threshold generation circuit 32. The dynamic threshold generation circuit 33 is used to generate at least two analog threshold signals to a time digital converter 33 based on the digital signal. The time digital converter 32 is used to sample and process the echo signal based on the threshold signal. Through the above process, it is possible to sample and process the echo signal through multiple threshold signals, which is conducive to distinguishing echo signals with different amplitudes, thereby improving the sampling accuracy and improving the detection performance of the laser detection device. In addition, the threshold signal generated by the dynamic threshold generation circuit 33 can change with the change of the digital signal, and then in different application scenarios, the controller 31 can be made to output a corresponding digital signal to obtain the required threshold signal, thereby meeting the needs of different application scenarios, and having strong practicality.

[0035] In some embodiments, the controller 31 can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a single-chip microcomputer, an ARM (Acorn RISC Machine) or other programmable logic device, a discrete gate or transistor logic, a discrete hardware component, or any combination of these components. In addition, the controller 31 can also be any conventional processor, controller, microcontroller or state machine. The controller 31 can also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a DSP, and / or any other such configuration.

[0036] In some embodiments, the time-to-digital converter 32 is further configured to output a pulse signal based on the sampling processing result, wherein the pulse signal includes at least one pulse, and each pulse is output when the echo signal is greater than or equal to the threshold signal.

[0037] For details, please refer to Figure 2 , Figure 2 The following is an example showing a method of threshold signal, echo signal and pulse signal. Figure 2 As shown, curve L11 is one of the threshold signals generated by the dynamic threshold generating circuit 32 (referred to as the first threshold signal here); curve L12 is the echo signal; and curve L13 is the pulse signal.

[0038] In the time period between time t11 and time t12, the echo signal remains or is equal to the first threshold signal, and the time digital converter 32 outputs a pulse. Then, the time digital converter 32 can also determine the distance from the target object 2 to the location of the laser detection device 1 and the strength of the echo signal based on the pulse, for example, the strength of the echo signal can be determined based on the width of the pulse.

[0039] However, in the related art, due to the hardware defects of the laser detection device, the echo signal is usually sampled and processed by only one threshold signal. It is difficult to achieve the sampling and processing of different echo signals by setting a single threshold signal, which leads to poor sampling accuracy and further affects the detection performance of the laser detection device. Figure 3 Provide explanation.

[0040] The first case is Figure 3 As shown in part (a) of FIG. 1 , curve L21 is the threshold signal; curve L22 is the echo signal; and curve L23 is the pulse signal. Specifically, the echo signal is a single peak, and at the same time, part of the echo signal is greater than the threshold signal, and part is less than the threshold signal. At this time, the pulse signal has pulse generation, that is, in the time period between time t21 and time t22, the echo signal remains or is equal to the threshold signal, and at this time, the time digital converter 32 outputs a pulse.

[0041] The second case is Figure 3 As shown in part (b) of the figure, curve L31 is the threshold signal; curve L32 is the echo signal; curve L33 is the signal output by the time digital converter 33 (at this time, since there is no pulse, it is not called a pulse signal). In this case, the threshold signal remains greater than the echo signal, and the time digital converter 33 no longer outputs pulses, so it is impossible to sample and process the echo signal, and further, it is impossible to detect the target object 2, resulting in poor detection performance of the laser detection device. In this case, it can be determined that the threshold signal is set too large.

[0042] The third situation is Figure 3 As shown in part (c) of the figure, curve L41 is the threshold signal; curve L42 is the echo signal; and curve L43 is the pulse signal. Specifically, the echo signal is two wave peaks (here, this type of echo signal is called a continuous wave), and at the same time, part of the echo signal is greater than the threshold signal, and part is less than the threshold signal. At this time, a pulse signal is generated based on the signal greater than the threshold. Moreover, in the time period between time t41 and time t42, the intensity of the echo signal is greater than or equal to the threshold signal, and at this time the time digital converter 32 outputs the first pulse; in the time period between time t43 and time t44, the echo signal intensity is greater than or equal to the threshold signal, and at this time the time digital converter 32 outputs the second pulse. It can be seen that for the continuous wave signal, two pulses can be obtained under the premise of reasonably configuring the threshold signal.

[0043] The fourth case is Figure 3As shown in part (d) of the figure, curve L51 is the threshold signal; curve L52 is the echo signal; and curve L53 is the pulse signal. In this case, although the echo signal is continuous, the echo signal strength is greater than or equal to the threshold signal in the time period from t51 to t52, and the time-to-digital converter 32 only outputs one pulse. It can be seen that there is an error in the sampling process of the echo signal, and thus the detection of the target object 2 is inevitably wrong, resulting in poor detection performance of the laser detection device. Therefore, in this case, due to inappropriate threshold setting, inaccurate detection information will be caused.

[0044] As for the present application, the embodiment of the present application adopts multiple threshold signals to adapt to different echo signals, so as to complete accurate sampling and processing of different echo signals, which is beneficial to prevent the problems existing in the above situation and improve the detection performance of the laser detection device 1.

[0045] At the same time, a method for adjusting the digital signal to dynamically adjust the threshold signal to adapt to different echo signals is also provided. Specifically, the controller is also used to adjust the digital signal based on the pulse signal to adjust the threshold signal output by the dynamic threshold generation circuit.

[0046] In one embodiment, the controller is also used to adjust the digital signal based on the pulse signal to adjust the threshold signal output by the dynamic threshold generating circuit. A specific implementation process is: if it is determined that there is a pulse with a pulse width greater than a preset width in the pulse signal, the controller is also used to adjust the digital signal to increase the threshold signal output by the dynamic threshold generating circuit.

[0047] The preset width is a preset width, which can be set based on actual application scenarios, and is not specifically limited in the embodiments of the present application. For example, in some embodiments, when the echo signal is determined to be a single peak signal, the maximum width of the pulse that may appear for the echo signal can be obtained, and the maximum width is used as the preset width in the above embodiment.

[0048] Then, if there is a pulse with a pulse width greater than the preset width in the pulse signal, it is determined that the echo signal may be a continuous wave. At this time, the digital signal can be adjusted to increase the threshold signal output by the dynamic threshold generation circuit to further determine whether the echo signal is a continuous wave.

[0049] by Figure 3 For example, when there is a pulse with a width greater than the preset width in the pulse signal, the actual signal may be as follows Figure 3 At this time, the digital signal can be adjusted to increase the threshold signal, and then if the echo signal is a continuous wave, two pulses can be obtained by increasing the threshold signal, for example Figure 3 As shown in part (c) of .

[0050] On the contrary, in other embodiments, if the continuous wave is still not detected after adjusting the digital signal to increase the threshold signal, it can be determined that the echo signal is a signal with a single peak, and the digital signal should be adjusted to reduce the threshold signal. The specific implementation process is as follows: the controller is also used to adjust the digital signal to reduce the threshold signal output by the dynamic threshold generation circuit if only one pulse is detected within a detection cycle after adjusting the digital signal to increase the threshold signal output by the dynamic threshold generation circuit. Optionally, the controller is also used to switch to a high threshold if the detection pulse width exceeds the single pulse upper limit value after adjusting the digital signal to reduce the threshold signal generated by the dynamic threshold.

[0051] Among them, only one pulse is detected in one detection cycle, which can determine that the echo signal is not a continuous wave, but a signal with a single peak. By adjusting the digital signal to reduce the threshold signal, it is possible to prevent the occurrence of such as the threshold signal being set too large. Figure 3 The abnormal situation in which the pulse signal is not monitored, or the abnormal situation in which the pulse width is less than the preset width as shown in part (b) is beneficial to improving the detection performance of the laser detection device 1.

[0052] Please refer to Figure 4 , Figure 4 A structure of a laser echo signal processing circuit provided in an embodiment of the present application. In one embodiment, Figure 4 As shown, the controller 31 includes a first digital signal input / output port IO1, and the digital signal output by the first digital signal input / output port IO1 includes a pulse width modulation signal P1. The pulse width modulation (PWM) signal P1 is a modulation technology used to control electronic devices, which transmits information or controls output by changing the width of the pulse.

[0053] Specifically, the dynamic threshold generation circuit 32 includes a filter branch 321. The filter branch 321 is electrically connected between the first digital signal input and output port IO1 and the time digital converter 33. The filter branch 321 is used to receive the pulse width modulation signal P1 and filter the pulse width modulation signal P1 to generate the threshold signal P2. In other words, in this embodiment, the signal after the pulse width modulation signal P1 is filtered is the threshold signal P2. Among them, the pulse width modulation signals P1 with different duty cycles correspond to different threshold signals P2. It can be seen that in this embodiment, by adjusting the duty cycle of the pulse width modulation signal P1, the threshold signal P2 can be adjusted, thereby providing different threshold signals P2 for the time digital converter 33.

[0054] In one embodiment, if Figure 5As shown, the controller 31 also includes a second digital signal input and output port IO2. The digital signal output by the second digital signal input and output port IO2 also includes a first high level signal V1 or a low level signal V2. The dynamic threshold generation circuit 32 also includes a summing branch 322. The summing branch 322 is electrically connected to the filtering branch 321, the second digital signal input and output port IO2 and the time-to-digital converter 33 respectively.

[0055] The summing branch 322 is used to sum the voltage signal obtained based on the first high-level signal V1 or the low-level signal V2 with the voltage signal P3 obtained after filtering the pulse width modulation signal P1 to generate a threshold signal P2. When the duty cycle of the pulse width modulation signal P1 remains unchanged, the threshold signals P2 corresponding to the first high-level signal V1 and the low-level signal C2 are different. Specifically, when the controller 31 outputs the first high-level signal V1, the summing branch 322 outputs a threshold signal P2 based on the result of summing the first high-level signal V1 and the voltage signal P3; when the controller 31 outputs the low-level signal V2, the summing branch 322 outputs another threshold signal P2 based on the result of summing the low-level signal V2 and the voltage signal P3. It can be seen that by outputting two signals of different levels through the second digital signal input and output port IO2 of the controller 31, the summing branch 322 can provide two threshold signals P2 for the time-to-digital converter 33, so that the time-to-digital converter 33 can sample and process different echo signals to improve the detection performance of the laser detection device. Secondly, the signal output by the second digital signal input / output port IO2 of the controller 31 can be switched quickly, so that fast switching of different threshold signals P2 can be achieved, which can improve the efficiency and accuracy of sampling and processing different echo signals. In addition, by increasing the digital signal input / output port (similar to the second digital signal input / output port IO2) of the controller 31 outputting the level signal in the same manner, the summing branch 322 can provide more threshold signals P2 for the time-to-digital converter 33 to meet the needs of different application scenarios, which has high practicality.

[0056] Please refer to Figure 6 , Figure 6 An example is shown with Figure 5 A circuit structure corresponding to the structure shown.

[0057] In one embodiment, if Figure 6 As shown, the filtering branch 321 includes a first resistor R1 and a first capacitor C1.

[0058] The first resistor R1 and the first capacitor C1 are connected in series between the first digital signal input / output port IO1 and the ground, and a common node between the first resistor R1 and the first capacitor C1 is electrically connected to the time-to-digital converter 33 via a summing branch 322 .

[0059] Specifically, the first resistor R1 and the first capacitor C1 form an RC filter. After the pulse width modulation signal output by the first digital signal input and output port IO1 is filtered by the first resistor R1 and the first capacitor C1, a threshold voltage can be provided for the time digital converter 33. In addition, by changing the duty cycle of the pulse width modulation signal, different threshold voltages can be provided for the time digital converter 33. Secondly, in this embodiment, only the first resistor R1 and the first capacitor C1 with lower prices are used, so the cost is lower.

[0060] In another embodiment, the summing branch 322 includes a second resistor R2 and a third resistor R3 .

[0061] The second resistor R2 is electrically connected between the filter branch 321 and the time-to-digital converter 33 , and the third resistor R3 is electrically connected between the second digital signal input / output port IO2 and the time-to-digital converter 33 .

[0062] Specifically, the combination of the second resistor R2 and the third resistor R3 can sum the signal (the first high-level signal V1 or the low-level signal V2) output by the second digital signal input / output port IO2 and the pulse width modulation signal output by the first digital signal input / output port IO1 after filtering in a certain ratio (the specific ratio is determined by the resistance values ​​of the second resistor R2 and the third resistor R3), and output the threshold signal P2 to the time digital converter 33 based on the summation result.

[0063] In summary, Figure 6 In the embodiment shown, three methods for changing the threshold signal P2 are provided to meet the needs of different application scenarios, and the practicality is high. Among them, the first method is to change the threshold signal P2 by changing the duty cycle of the pulse width modulation signal; the second method is to keep the duty cycle of the pulse width modulation signal unchanged and change the threshold signal P2 by switching the first high level signal V1 and the low level signal V2; the third method is to change the threshold signal P2 by changing the duty cycle of the pulse width modulation signal and switching the first high level signal V1 and the low level signal V2. In addition, the method of changing the threshold signal P2 by switching the first high level signal V1 and the low level signal V2 is also fast, so as to improve the efficiency and accuracy of target detection.

[0064] It should be noted that if Figure 6 The hardware structure of the laser echo signal processing circuit 30 shown is only an example, and the laser echo signal processing circuit 30 may have more or fewer components than shown in the figure, may combine two or more components, or may have different component configurations. The various components shown in the figure may be implemented in hardware, software, or a combination of hardware and software including one or more signal processing and / or application-specific integrated circuits.

[0065] For example, in one embodiment, Figure 7 As shown, the filter branch 321 can also be provided with one more RC filter combination, that is, the filter branch 321 further includes a second capacitor C2 and a fifth resistor R5.

[0066] The fifth resistor R5 and the second capacitor C2 are connected in series between the first digital signal input / output port IO1 and ground, and a common node between the fifth resistor R5 and the second capacitor C2 is electrically connected to the time-to-digital converter 33 via the first resistor R1 and the summing branch 322 .

[0067] Specifically, the fifth resistor R5 and the second capacitor C2 form an RC filter. After the pulse width modulation signal output by the first digital signal input and output port IO1 passes through two RC filters (an RC filter formed by the fifth resistor R5 and the second capacitor C2 and an RC filter formed by the first resistor R1 and the first capacitor C1), a threshold voltage can be provided for the time digital converter 33. Similarly, by changing the duty cycle of the pulse width modulation signal, different threshold voltages can be provided for the time digital converter 33.

[0068] For example, in one embodiment, the controller 31 further includes a third digital input / output port IO3, and the third digital input / output port IO3 can also output a first high level signal V1 and a low level signal V2. The summing branch 322 further includes a sixth resistor R6.

[0069] The sixth resistor R6 is connected between the third digital input / output port IO3 and the time-to-digital converter 33 .

[0070] Specifically, the combination of the second resistor R2, the third resistor R3 and the sixth resistor R6 can sum the filtered signal of the signal output from the third digital signal input / output port IO3, the signal output from the second digital signal input / output port IO2, and the pulse width modulation signal output from the first digital signal input / output port IO1 in a certain ratio (the specific ratio is determined by the resistance values ​​of the second resistor R2 and the third resistor R3), and output the threshold signal P2 to the time digital converter 33 based on the summation result.

[0071] Please refer to Figure 8 , Figure 8 FIG. 1 is a schematic diagram of a laser echo signal processing circuit provided in another embodiment of the present application. Figure 8 As shown, the dynamic threshold generating circuit 32 further includes a level conversion branch 323 .

[0072] Among them, the level conversion branch 323 is connected between the second digital signal input and output port IO2 and the summing branch 322. The level conversion branch 323 is used to output a second high level signal V3 or a low level signal V2 based on the digital signal output by the second digital signal input and output port IO2. Among them, the voltage corresponding to the first high level signal V1 and the second high level signal V2 are different, so as to realize the level conversion process. For example, in some embodiments, the voltage corresponding to the first high level signal V1 output by the second digital signal input and output port IO2 is 3.3V, and the voltage corresponding to the second high level signal V3 output by the level conversion branch 323 is set to 5V to meet the needs of different application scenarios.

[0073] The summing branch 322 is also used to sum the voltage signal obtained based on the second high-level signal V3 or the low-level signal V2 with the voltage signal P3 obtained after filtering the pulse width modulation signal to generate a threshold signal P2. When the duty cycle of the pulse width modulation signal P1 remains unchanged, the threshold signals corresponding to the second high-level signal V3 and the low-level signal V2 are different. Specifically, when the level conversion branch 323 outputs the second high-level signal V3, the summing branch 322 outputs a threshold signal P2 based on the result of summing the second high-level signal V3 and the voltage signal P3; when the level conversion branch 323 outputs the low-level signal V2, the summing branch 322 outputs another threshold signal P2 based on the result of summing the low-level signal V2 and the voltage signal P3. It can be seen that by outputting two signals of different levels through the level conversion branch 323, the summing branch 322 can provide two threshold signals P2 for the time digital converter 33, so that the time digital converter 33 can sample and process different echo signals to improve the detection performance of the laser detection device. Moreover, the signal output by the second digital signal input / output port IO2 of the controller 31 can be quickly switched, and the signal output by the level conversion branch 323 can also be quickly switched, so that fast switching of different threshold signals P2 can be achieved, which is conducive to improving the efficiency and accuracy of sampling and processing different echo signals. In addition, when a digital signal input / output port (similar to the second digital signal input / output port IO2) for outputting a level signal of the controller 31 is increased in the same manner, a level conversion branch 323 can also be correspondingly increased, so that the summing branch 322 provides more threshold signals P2 for the time digital converter 33, thereby meeting the needs of different application scenarios, and having high practicality.

[0074] Optionally, as another optional implementation, a level conversion path or a driving circuit may be included between the controller IO1 and the filter branch to adjust the voltage value P1 of the signal output by the controller PWM wave, thereby achieving more flexible adjustment of the voltage range P3 of the filter output.

[0075] Optionally, further, in the Figure 8 In the circuit architecture shown, an operational amplifier or an operational amplifier circuit can be added after any or all of the controller input / output port IO1, the controller input / output port IO2, the filter branch 321 output port, and the summing branch output port, so as to further change the impedance matching characteristics and improve the threshold establishment performance.

[0076] Among them, as an optional implementation, the filter branch 321 can use an RC passive filter or an active filter built with an operational amplifier. The present application does not impose any sole restriction on the specific form of the filter used in the filter branch.

[0077] As an optional implementation, the summing branch 322 may use direct resistor addition or a summing circuit including an operational amplifier. The present application does not impose any limitation on the specific addition form used by the summing branch 322.

[0078] Please refer to Fig. 9 , Fig. 9 Shown with Figure 8 A circuit corresponding to the structure shown. And, Fig. 9 The circuit shown is based on Figure 6 The circuit shown is taken as an example in which a level conversion branch 323 is added.

[0079] In one embodiment, if Fig. 9 As shown, the level conversion branch 323 includes a switch tube Q1 and a fourth resistor R4.

[0080] Among them, the control end of the switch tube Q1 is electrically connected to the second digital signal input and output port IO2, one end of the non-control end of the switch tube Q1 is electrically connected to the first end of the fourth resistor R4 and the summing branch 322, the other end of the non-control end of the switch tube Q1 is grounded, and the second end of the fourth resistor R4 inputs the voltage Vin corresponding to the second high level signal V2.

[0081] Specifically, when the second digital signal input / output port IO2 outputs the first high level signal V1, the switch tube Q1 is turned on, and the common node between the switch tube Q1 and the fourth resistor R4 is forced to be pulled low, thereby inputting the low level signal into the summing branch 322 .

[0082] When the second digital signal input / output port IO2 outputs a low level signal V2, the switch tube Q1 is turned off. The voltage Vin is input to the summing branch 322 through the fourth resistor R4, thereby inputting the second high level signal V3 to the summing branch 322.

[0083] In summary, the level conversion process is realized, which can be applied to application scenarios with different level requirements and is highly practical.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Under the concept of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes in different aspects of the present application as described above, which are not provided in detail for the sake of simplicity. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A laser detection device, characterized in that: include: A laser transmitter, used for transmitting laser light to a target object; A laser detector, used to receive an echo signal reflected by the target object; A laser echo signal processing circuit, used for sampling and processing the echo signal; Wherein, the laser echo signal processing circuit includes a controller, a time-to-digital converter and a dynamic threshold generation circuit, and the controller is electrically connected to the time-to-digital converter through the dynamic threshold generation circuit; The controller is used to output a digital signal to the dynamic threshold generation circuit; The dynamic threshold generation circuit is used to generate at least two analog threshold signals to the time-to-digital converter based on the digital signal; The time-to-digital converter is used for performing sampling processing on the echo signal based on the threshold signal.

2. The laser detection device according to claim 1, characterized in that: The controller comprises a first digital signal input / output port, and the digital signal output by the first digital signal input / output port comprises a pulse width modulation signal; The dynamic threshold generation circuit includes a filter branch, which is electrically connected between the first digital signal input and output port and the time-to-digital converter. The filter branch is used to receive the pulse width modulation signal and filter the pulse width modulation signal to generate the threshold signal; wherein the pulse width modulation signals with different duty cycles correspond to different threshold signals.

3. The laser detection device according to claim 2, characterized in that: The controller further comprises a second digital signal input / output port, and the digital signal output by the second digital signal input / output port further comprises a first high level signal or a low level signal; The dynamic threshold generation circuit also includes a summing branch, which is electrically connected to the filtering branch, the second digital signal input and output port and the time-to-digital converter respectively, and is used to sum a voltage signal obtained based on the first high-level signal or the low-level signal with a voltage signal obtained after filtering the pulse width modulation signal to generate the threshold signal; wherein, when the duty cycle of the pulse width modulation signal remains unchanged, the threshold signals corresponding to the first high-level signal and the low-level signal are different.

4. The laser detection device according to claim 3, characterized in that: The dynamic threshold generation circuit also includes a level conversion branch; The level conversion branch is connected between the second digital signal input / output port and the summing branch, and the level conversion branch is used to output a second high level signal or the low level signal based on the digital signal output by the second digital signal input / output port, wherein the voltages corresponding to the first high level signal and the second high level signal are different; The summing branch is also used to sum the voltage signal obtained based on the second high-level signal or the low-level signal with the voltage signal obtained after filtering the pulse width modulation signal to generate the threshold signal; wherein, when the duty cycle of the pulse width modulation signal remains unchanged, the threshold signals corresponding to the second high-level signal and the low-level signal are different.

5. The laser detection device according to claim 2, characterized in that: The filtering branch includes a first resistor and a first capacitor; The first resistor and the first capacitor are connected in series between the first digital signal input / output port and ground, and a common node between the first resistor and the first capacitor is electrically connected to the time-to-digital converter.

6. The laser detection device according to claim 3, characterized in that: The summing branch includes a second resistor and a third resistor; The second resistor is electrically connected between the filter branch and the time-to-digital converter, and the third resistor is electrically connected between the second digital signal input / output port and the time-to-digital converter.

7. The laser detection device according to claim 4, characterized in that: The level conversion branch includes a switch tube and a fourth resistor; The control end of the switch tube is electrically connected to the second digital signal input and output port, one end of the non-control end of the switch tube is electrically connected to the first end of the fourth resistor and the summing branch, the other end of the non-control end of the switch tube is grounded, and the second end of the fourth resistor inputs the voltage corresponding to the second high level signal; When the second digital signal input / output port outputs the first high level signal, the switch tube is turned on to output the low level signal; when the second digital signal input / output port outputs the low level signal, the switch tube is turned off to output the second high level signal.

8. The laser detection device according to claim 1, characterized in that: The time-to-digital converter is further used to output a pulse signal based on the sampling processing result, wherein the pulse signal includes at least one pulse, and each pulse is output when the echo signal is greater than or equal to the threshold signal; The controller is further configured to adjust the digital signal based on the pulse signal to adjust the threshold signal output by the dynamic threshold generation circuit.

9. The laser detection device according to claim 8, characterized in that: The controller is further configured to adjust the digital signal to increase the threshold signal output by the dynamic threshold generation circuit if it is determined that a pulse having a pulse width greater than a preset width exists in the pulse signal.

10. The laser detection device according to claim 9, characterized in that: The controller is also used to adjust the digital signal to reduce the threshold signal output by the dynamic threshold generation circuit after adjusting the digital signal to increase the threshold signal output by the dynamic threshold generation circuit if only one pulse is detected within a detection cycle.

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