CN117665768A - Laser radar, signal acquisition circuit and signal acquisition method thereof - Google Patents

Abstract

The invention provides a laser radar, a signal acquisition circuit and a signal acquisition method thereof, wherein the signal acquisition circuit comprises: the system comprises a detector, a selection module, an integration module and a signal acquisition module; the selection module is coupled with the integration module and used for controlling the signal acquisition circuit to switch working modes, wherein the working modes comprise a return light signal acquisition mode and an ambient light measurement mode; the integrating module is coupled with the detector and the selecting module and is used for integrating the electric signal generated by the detector in an ambient light measuring mode and outputting an ambient light integrated signal; the input end of the signal acquisition module is coupled with the detector and the integration module and is used for acquiring an electric signal generated by the detector in a return light signal acquisition mode or acquiring an ambient light integration signal in an ambient light measurement mode. The technical scheme of the invention can reduce the cost of the signal acquisition circuit, and can also lead the structure of the signal acquisition circuit to be simple and the area to be smaller.

Description

Laser radar, signal acquisition circuit and signal acquisition method thereof

Technical Field

The invention relates to the field of laser radars, in particular to a laser radar, a signal acquisition circuit and a signal acquisition method thereof.

Background

The laser radar can obtain the relevant information of the target object, such as parameters of distance, azimuth, altitude, speed, gesture, even shape, and the like, by emitting a detection signal (e.g. a laser beam) to the target object, and then comparing the received signal (return light signal) reflected from the target object with the emission signal, and performing proper processing. Besides responding to the return light signal, the laser radar also responds to the ambient light in the working process, and the magnitude of the ambient light can influence the waveform of the return light signal so as to influence the detection accuracy, so that the return light signal can be calibrated by collecting the ambient light.

In the prior art, for the function of measuring the ambient light of the laser radar, a low-speed analog-digital converter (Analog to Digital Converter, ADC) is additionally added to collect a direct current photocurrent signal, so that the ambient light is obtained.

However, the prior art requires the use of low speed ADCs, which are costly and add to the effort of the field programmable gate array (Field Programmable Gate Array, FPGA).

Disclosure of Invention

The invention solves the technical problem of reducing the cost of a signal acquisition circuit.

To solve the above technical problem, in a first aspect, an embodiment of the present invention provides a signal acquisition circuit for a lidar driving circuit, the signal acquisition circuit includes: the system comprises a detector, a selection module, an integration module and a signal acquisition module; the selection module is coupled with the integration module and is used for controlling the signal acquisition circuit to switch working modes, wherein the working modes comprise a return light signal acquisition mode and an ambient light measurement mode; the integration module is coupled with the detector and the selection module and is used for integrating the electric signal generated by the detector in an ambient light measurement mode and outputting an ambient light integration signal; the input end of the signal acquisition module is coupled with the detector and the integration module and is used for acquiring an electric signal generated by the detector in the return light signal acquisition mode or acquiring the ambient light integration signal in the ambient light measurement mode.

Optionally, in the ambient light measurement mode, the integrating module integrates the electrical signal generated by the detector and outputs the ambient light integrated signal to the signal collecting module, and the signal collecting module collects the ambient light integrated signal.

Optionally, in the return light signal acquisition mode, an electrical signal generated by the detector is output to the signal acquisition module, and the signal acquisition module acquires the electrical signal.

Optionally, the integrating module includes: and the first end of the integration unit is connected with the electric signal generated by the detector, the second end of the integration unit is connected with a bias power supply, and the integration unit is used for integrating the electric signal generated by the detector in the ambient light measurement mode.

Optionally, the integrating module further includes: the first end of the impedance unit is coupled with the second end of the detector, the second end of the impedance unit is coupled with the first end of the integration unit, and the impedance unit is used for blocking the electric signal from being input into the integration unit in the return light signal acquisition mode and enabling the electric signal to be input into the integration unit in the ambient light measurement mode.

Optionally, the impedance unit has a first impedance, the signal acquisition module has a second impedance, and in the return signal acquisition mode, the first impedance is greater than the second impedance; in the ambient light measurement mode, the first impedance is less than the second impedance.

Optionally, in the return signal acquisition mode, the selection module shorts the first end and the second end of the integration unit; in the ambient light measurement mode, the selection module enables the first end and the second end of the integration unit to be in non-short connection, and enables the first end and the second end of the integration unit to be in short connection after a preset time length.

Optionally, the selecting module includes: any one of a PMOS tube, an NMOS tube and an analog switch; the PMOS tube is connected in parallel with the integration unit, and the control end of the PMOS tube is connected with a control signal; the NMOS tube is connected in parallel with the integration unit, and the control end of the NMOS tube is connected with a control signal; the analog switch is connected with the integration unit in parallel, and the control end of the analog switch is connected with a control signal.

Optionally, the signal acquisition module includes: the first end of the capacitor is coupled with the second end of the detector, and the first end of the detector is connected with a driving power supply; the input end of the acquisition unit is coupled with the second end of the capacitor, and the output end of the acquisition unit outputs a measuring signal.

Optionally, the signal acquisition module includes: the first end of the capacitor is coupled with the second end of the detector, and the first end of the detector is connected with a driving power supply; an amplifier, an input end of the amplifier is coupled with a second end of the capacitor; the input end of the acquisition unit is coupled with the output end of the amplifier, and the output end of the acquisition unit outputs a measuring signal.

In a second aspect, the embodiment of the invention also discloses a signal acquisition method for a laser radar, which comprises the following steps: the signal acquisition circuit is controlled to switch working modes, wherein the working modes comprise a return light signal acquisition mode and an ambient light measurement mode; if the working mode is the ambient light measurement mode, the integration module is controlled to integrate the electric signal generated by the detector and output an ambient light integration signal to the signal acquisition module, and the signal acquisition module acquires the ambient light integration signal; and if the working mode is the return light signal acquisition mode, controlling the electric signal generated by the detector to be output to the signal acquisition module, and acquiring the electric signal by the signal acquisition module.

Optionally, the method for controlling the ambient light measurement mode includes: opening an integration channel of the integration module; and closing the integrating channel after the preset time.

Optionally, the operating mode is the ambient light measurement mode, and controlling the integrating module to integrate the electrical signal generated by the detector and outputting the ambient light integrated signal to the collecting module includes: the selection module is switched to an ambient light measurement mode; opening the integration channel, and controlling the integration module to integrate the electric signal generated by the detector within a preset time length; and closing the integration channel, and controlling the integration module to output an integration signal.

Optionally, the control method of the return light signal acquisition mode includes: closing the integrating channel.

In a third aspect, an embodiment of the present invention further provides a lidar, where the lidar includes a signal acquisition circuit for the lidar.

Compared with the prior art, the technical scheme of the embodiment of the invention has the following beneficial effects:

in the technical scheme of the invention, the signal acquisition circuit comprises a detector, a selection module, an integration module and a signal acquisition module; the selection module can control the signal acquisition circuit to switch the working mode, the signal acquisition module acquires the electric signal generated by the detector in the return light signal acquisition mode, and the signal acquisition module acquires the ambient light integral signal output by the integral module in the ambient light measurement mode. The multiplexing signal acquisition module is used for respectively acquiring the return light signal and the environment light signal in two working modes. The signal acquisition module acquires the electric signal generated by the detector in a return light signal acquisition mode, integrates the electric signal generated by the detector in an ambient light acquisition mode through the integration module and converts the integrated electric signal into an ambient light integrated signal, and the ambient light integrated signal is acquired by the signal acquisition module, so that signal conversion devices such as a low-speed analog-to-digital converter and the like are not required to be additionally introduced, and the circuit cost is reduced; in addition, can also make signal acquisition circuit's simple structure, the area is littleer.

Further, the integrating module comprises an integrating unit and an impedance unit, the integrating unit is used for integrating the electric signal generated by the detector in the ambient light measuring mode, and the impedance unit is used for blocking the electric signal from being input into the integrating unit in the return light signal acquisition mode and enabling the electric signal to be input into the integrating unit in the ambient light measuring mode. In the technical scheme of the application, the signal acquisition module acquires the return light signal and the ambient light signal at different moments, and through setting the impedance unit in the integration module, the mutual interference of the two signals can be avoided, and the accuracy of signal acquisition is ensured on the basis of ensuring simple circuit structure and low cost.

Drawings

FIG. 1 is a schematic diagram of a prior art signal acquisition circuit;

fig. 2 is a schematic structural diagram of a signal acquisition circuit according to an embodiment of the present invention;

fig. 3 is a schematic diagram of another signal acquisition circuit according to an embodiment of the present invention;

fig. 4 is a schematic diagram of a specific structure of a signal acquisition circuit according to an embodiment of the present invention;

fig. 5 is a schematic diagram of a specific structure of another signal acquisition circuit according to an embodiment of the present invention;

fig. 6 is a schematic diagram of a specific structure of a signal acquisition circuit according to another embodiment of the present invention;

Fig. 7 is a schematic diagram of a specific structure of a signal acquisition circuit according to another embodiment of the present invention;

fig. 8 is a schematic diagram of a specific structure of a signal acquisition circuit according to another embodiment of the present invention;

fig. 9 is a schematic diagram of a specific structure of a signal acquisition circuit according to another embodiment of the present invention;

fig. 10 is a schematic structural diagram of a signal acquisition circuit according to another embodiment of the present invention;

fig. 11 is a flowchart of a signal acquisition method according to an embodiment of the present invention.

Detailed Description

Specifically, referring to fig. 1, two interfaces exist for the output of the detector D0: standard output interfaces (standard out) and fast output interfaces (fastout). The pulse output by the fast output interface is narrower, and is used for detecting a target and acquiring Time Of Flight (TOF), and the fast output interface is required to be connected with a high-speed ADC with higher acquisition frequency to meet the requirement Of pulse acquisition due to the narrower pulse signal. The standard output interface is connected with an integrating circuit consisting of an amplifier AMP and an RC circuit, accumulates for a period of time, such as 500 nanoseconds (ns), before lighting or in idle time, reads out the amplitude by using a low-speed ADC, and the output amplitude is indicative of the ambient light intensity.

As described in the background art, the prior art needs to use a high-speed ADC and a low-speed ADC simultaneously, which respectively meet the requirement of the acquisition of the TOF signal and the acquisition of the ambient light signal, while the low-speed ADC has high cost and increases the workload of the field programmable gate array (Field Programmable Gate Array, FPGA).

In the technical scheme of the invention, the signal acquisition circuit comprises a detector, a selection module, an integration module and a signal acquisition module; the selection module can control the signal acquisition circuit to switch the working mode, the signal acquisition module acquires the electric signal generated by the detector in the return light signal acquisition mode, and the signal acquisition module acquires the ambient light integral signal output by the integral module in the ambient light measurement mode. The multiplexing signal acquisition module of this application for signal acquisition module gathers back light signal and environment light signal respectively under two kinds of operating modes. The signal acquisition module acquires the electric signal generated by the detector in a return light signal acquisition mode, integrates the electric signal generated by the detector in an ambient light acquisition mode through the integration module and converts the integrated electric signal into an ambient light integrated signal, and the ambient light integrated signal is acquired by the signal acquisition module, so that signal conversion devices such as a low-speed analog-to-digital converter and the like are not required to be additionally introduced, and the circuit cost is reduced; in addition, can also make signal acquisition circuit's simple structure, the area is littleer. Further, when the detector detects signals, the signal acquisition circuit works in a return signal acquisition mode to acquire return signals; when the detector does not detect, namely does not measure distance, the signal acquisition circuit works in an ambient light measurement mode to acquire ambient light.

Further, the integrating module comprises an integrating unit and an impedance unit, the integrating unit is used for integrating the electric signal generated by the detector in the ambient light measuring mode, and the impedance unit is used for blocking the electric signal from being input into the integrating unit in the return light signal acquisition mode and enabling the electric signal to be input into the integrating unit in the ambient light measuring mode. In the technical scheme of the application, the signal acquisition module acquires the return light signal and the ambient light signal at different moments, and through setting the impedance unit in the integration module, the mutual interference of the two signals can be avoided, and the accuracy of signal acquisition is ensured on the basis of ensuring simple circuit structure and low cost.

In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings.

Fig. 2 is a schematic structural diagram of a signal acquisition circuit according to an embodiment of the present invention. The signal acquisition circuit provided by the embodiment of the invention is used in a laser radar.

The signal acquisition circuit includes a detector 10, a selection module 20, an integration module 30, and a signal acquisition module 40.

Specifically, one end of the detector 10 is connected to a driving power supply, for example, the driving power supply circuit is a direct current power supply; the drive power supply is capable of driving the detector 10 to receive photons to produce an electrical signal. The detector 10 may be a silicon photomultiplier (SiPM), a single photon avalanche diode (Single Photon Avalanche Diode, SPAD), or any other light emitting tube. In practical applications, the number of detectors 10 may be single or multiple, and embodiments of the present invention are not limited in this respect.

In this embodiment, the selection module 20 is configured to control the signal acquisition circuit to switch between a working mode including a return light signal acquisition mode and an ambient light measurement mode. The signal acquisition circuit acquires and outputs a return light signal in a return light signal acquisition mode, and the signal acquisition circuit acquires and outputs an ambient light signal in an ambient light measurement mode.

In particular, the first end of the integration module 30 is coupled to the second end of the detector 10, and the second end of the integration module 30 is connected to a bias power supply for providing a bias voltage. Specifically, the voltage difference between the dc power supply at one end of the detector 10 and the bias voltage is greater than or equal to the operating voltage of the detector 10, and the further bias voltage may also provide an on voltage for the selection module, which will be described later in the detailed description. The integrating module 30 integrates the electrical signal generated by the detector 10 in the ambient light measurement mode and outputs an ambient light integrated signal, and the signal collecting module 40 collects the ambient light integrated signal. Specifically, in the ambient light measurement mode, since ambient light is a sustained quantity, the detector is always excited to produce a relatively stable DC signal, i.e., the electrical signal produced by the detector 10 is a DC signal, which the integration module 30 can convert to an AC signal (i.e., an ambient light integration signal).

In a specific implementation, a first end of the signal acquisition module 40 is coupled to the detector 10, and a second end of the signal acquisition module 40 is an output end of the signal acquisition circuit. The output end of the signal acquisition circuit outputs an acquired signal, and the signal can be used for TOF calculation or calculation of the ambient light. The signal acquisition module 40 directly acquires the electrical signal generated by the detector 10 in the return signal acquisition mode. Specifically, in the return light signal acquisition mode, the electrical signal generated by the detector 10 is a pulsed signal.

In this embodiment, in the ambient light measurement mode, the integrating module 30 integrates the electrical signal generated by the detector 10 and outputs an ambient light integrated signal to the signal collecting module 40, wherein the electrical signal generated by the detector 10 in the ambient light measurement mode is a dc signal, the ambient light integrated signal is a pulse signal, and the signal collecting module 40 collects the ambient light integrated signal. Specifically, in the ambient light measurement mode, the electrical signal generated by the detector 10 is integrated in the integration module 30, so that the voltage difference is generated at two ends of the integration module 30, and after integration, the selection module 20 is controlled, so that the voltage difference at two ends of the integration module is suddenly changed, thereby generating a pulse signal, that is, an ambient light integration signal. In the return light signal acquisition mode, the electrical signal generated by the detector 10 is output to the signal acquisition module 40, and the signal acquisition module 40 acquires the electrical signal.

Specifically, the signal acquisition module 40 may process the collected return light signal or the ambient light integrated signal and output the processed return light signal or the ambient light integrated signal, for example, may perform analog-to-digital conversion on the collected return light signal or the ambient light integrated signal and output the processed return light signal or the ambient light integrated signal.

The multiplexing signal acquisition module 40 according to the embodiment of the present invention allows the signal acquisition module 40 to acquire the return light signal and the ambient light signal in two working modes, respectively. The signal acquisition module 40 acquires the electric signal generated by the detector in the return light signal acquisition mode, integrates the electric signal generated by the detector 10 in the ambient light acquisition mode through the integration module 30 and converts the integrated signal into an ambient light integrated signal, and the ambient light integrated signal is acquired by the signal acquisition module 40, so that signal conversion devices such as a low-speed analog-to-digital converter and the like are not required to be additionally introduced, and the circuit cost is reduced; in addition, the embodiment of the invention can also enable the signal acquisition circuit to have a simple structure and a smaller area. Further, when the detector detects signals, the signal acquisition circuit works in a return signal acquisition mode to acquire return signals; when the detector does not measure distance, the signal acquisition circuit works in an ambient light measurement mode to acquire ambient light, for example, when the laser radar has a plurality of detectors, the detector which does not measure distance and the corresponding signal acquisition circuit can acquire ambient light when other detectors measure distance, or the detector can acquire ambient light in a gap waiting for the next distance measurement after finishing one distance measurement, or other detectors can acquire ambient light when the other detectors do not need to measure distance.

In one non-limiting embodiment of the present application, referring to fig. 3, the integrating module 30 may include an integrating unit 301. The first end of the integration unit 301 is connected to the electrical signal generated by the detector 10, the second end of the integration unit 301 is connected to the bias power supply, and the integration unit 301 is used for integrating the electrical signal generated by the detector 10 in the ambient light measurement mode. The bias power supply can be used for controlling the selection module to switch the working modes, and particularly, the bias power supply can be matched with an external control signal to control the on-off of the selection module.

Specifically, in the ambient light measurement mode, the detector 10 collects ambient light to generate an electrical signal. The integrating unit 301 receives the electrical signal generated by the detector 10 and integrates the received electrical signal for a preset period of time to obtain an ambient light integrated signal. After a preset period of time, the integrating unit 301 outputs the integrated ambient light signal to the signal collecting module 40, and the signal collecting module 40 processes and outputs the integrated ambient light signal.

In the return light signal acquisition mode, the detector 10 acquires a return light signal and generates an electrical signal, the signal acquisition module 40 receives the electrical signal, and the signal acquisition module 40 processes and outputs the electrical signal.

Further, the integrating module 30 may further include an impedance unit 302. The first end of the impedance unit 302 is coupled to the second end of the detector 10, and the second end of the impedance unit 302 is coupled to the first end of the integration unit 301. The impedance unit 302 is configured to block an electrical signal from being input to the integration unit 301 in the return signal acquisition mode, and to enable the electrical signal to be input to the integration unit 301 in the ambient light measurement mode. Specifically, the signal acquisition module 40 has different impedance values at different signal frequencies, and has smaller impedance at high frequency signals and larger impedance at low frequency signals or direct current signals; in the return light signal collection mode, since the electrical signal output by the detector 10 is a high-frequency pulse signal, the impedance of the signal collection module 40 is small and the impedance of the impedance unit 302 in this case is large, so that the electrical signal output by the detector 10 enters the signal collection module 40; in the ambient light measurement mode, since the detector 10 outputs a relatively stable dc signal, the impedance of the signal acquisition module 40 increases and is much larger than the impedance of the impedance unit 302, so that the electrical signal output by the detector enters the integration unit 301 through the impedance unit 302.

In the embodiment of the invention, the signal acquisition module acquires the return light signal and the ambient light signal at different moments, and the impedance unit is arranged in the integration module, so that the mutual interference of the two signals can be avoided, and the accuracy of signal acquisition is ensured on the basis of ensuring the simple circuit structure and low cost.

Further, the impedance unit 302 has a first impedance, the signal acquisition module 40 has a second impedance, and in the return light signal acquisition mode, the first impedance is greater than the second impedance to block the input of the electrical signal to the integration unit 301, so that the electrical signal is input to the signal acquisition module 40. In the ambient light measurement mode, the first impedance is smaller than the second impedance so that the electrical signal is input to the integration unit 301.

In a specific example, the impedance value of the first impedance may be several hundred ohms or several kiloohms, and may be adaptively set according to an actual application scenario.

In this embodiment, in the return signal collection mode, the selection module 20 shorts the first end and the second end of the integration unit 301, and the integration unit 301 does not integrate the electrical signal generated by the detector. And at this time, the first impedance of the impedance unit 302 is greater than the second impedance of the signal acquisition module 40, so that the signal acquisition module 40 can perform normal return light signal acquisition.

In the ambient light measurement mode, the selection module 20 makes the first end and the second end of the integration unit 301 not short-circuited, and at this time, the first impedance of the impedance unit 302 is smaller than the second impedance of the signal acquisition module 40, and the integration unit 301 integrates the electrical signal generated by the detector. After a preset period of time, the selection module 20 shorts the first end and the second end of the integration unit 301, and the ambient light integrated signal output by the integration unit 301 is output to the signal acquisition module 40 via the impedance unit 302, so as to acquire ambient light.

In a specific embodiment, referring to fig. 4, fig. 4 shows a specific structure of a signal acquisition circuit.

In this embodiment, the driving power source HV is a negative voltage, the bias power source Vbias is a positive voltage, the purpose is to make the detector D1 have a reverse bias, and the voltage difference between the bias power source Vbias and the driving power source HV is the operating voltage of the detector D1. Meanwhile, the bias power supply Vbias also provides an opening voltage for the PMOS tube M1.

In this embodiment, the selection module includes a PMOS transistor M1, and the integration unit is a capacitor C2. The PMOS tube M1 is connected in parallel with the capacitor C2, and the control end of the PMOS tube M1 is connected with the control signal CTRL. Specifically, the source of the PMOS transistor M1 is coupled to the second end of the capacitor C2, the drain of the PMOS transistor M1 is coupled to the first end of the capacitor C2, and the gate of the PMOS transistor M1 is connected to the control signal CTRL. The PMOS transistor M1 can be controlled to be turned on and off by the control signal CTRL. Specifically, the gate of the PMOS transistor M1 is coupled to a field programmable gate array (Field Programmable Gate Array, FPGA), that is, the FPGA outputs a control signal CTRL, and the on/off of the PMOS transistor M1 is controlled by the control signal CTRL.

In this embodiment, the impedance unit includes a resistor R1, a first end of the resistor R1 is coupled to the cathode of the detector D1, and a second end of the resistor R1 is coupled to the first end of the capacitor C2.

In this embodiment, the signal acquisition module includes a capacitor C1 and an acquisition unit 401. The first end of the capacitor C1 is coupled to the cathode of the detector D1, and the anode of the detector is connected to the driving power supply HV. An input end of the acquisition unit 401 is coupled to the second end of the capacitor C1, and an output end of the acquisition unit 401 outputs a measurement signal OUT. In particular, the acquisition unit 401 may be an analog-to-digital converter, or may be any other signal conversion device that may be implemented, which is not limited in this application.

In specific implementation, in the initial state, the PMOS transistor M1 is in a conducting state, that is, the control signal CTRL is a low voltage signal, so that the voltage difference between the bias power source Vbias and the control signal CTRL is greater than or equal to the turn-on voltage of the PMOS transistor M1, and at this time, the voltage across the capacitor C2 is 0V. The detector D1, the capacitor C1 and the acquisition unit 401 may perform normal return light signal acquisition. Specifically, the return light signal detected by the detector D1 is a pulse signal, the pulse signal may be input to the acquisition unit 401 through the capacitor C1 by the electric signal generated by the detector D1, and the acquisition unit 401 converts the electric signal and outputs the converted electric signal.

In specific implementation, when ambient light collection is required, the PMOS transistor M1 is controlled to be turned off by the control signal CTRL, that is, the control signal CTRL is a high voltage signal, so that the voltage difference between the bias power source Vbias and the control signal CTRL is smaller than the turn-on voltage of the PMOS transistor M1. When the PMOS transistor M1 is turned off, the turn-off time is set to t nanoseconds (ns), and then the photocurrent responded by the detector D1 in the time charges the capacitor C2 and generates a voltage drop, and at this time, voltages at two ends of the capacitor C2 are different. Further, since the ambient photocurrent is a small direct current, it does not flow to the capacitor C1. After the turn-off time t nanoseconds, the PMOS transistor M1 is turned on from off, the charge on the capacitor C2 is discharged to 0V, and a part of the pulse current signal (i.e., the ambient light integrated signal) generated by the abrupt change of the voltage at the first end of the capacitor C2 is input to the acquisition unit 401 through the resistor R1 and the capacitor C1, and the acquisition unit 401 converts the signal and outputs the signal.

In a variation, referring to fig. 5, unlike the embodiment shown in fig. 4, the driving power source HV is positive voltage, and the voltage of the driving power source HV is greater than the voltage of the bias power source Vbias, so that the detector D1 has a reverse bias, and the voltage difference between the bias power source Vbias and the driving power source HV is the operating voltage of the detector D1. In addition, a first end of the capacitor C1 is coupled with an anode of the detector D1, and a cathode of the detector is connected with the driving power supply HV; the source of the PMOS tube M1 is coupled to the first end of the capacitor C2, the drain of the PMOS tube M1 is coupled to the second end of the capacitor C2, and the gate of the PMOS tube M1 is connected to the control signal CTRL.

In this embodiment, the driving power source HV is a negative voltage, the bias power source Vbias is a positive voltage, the purpose is to make the detector D1 have a reverse bias, and the voltage difference between the bias power source Vbias and the driving power source HV is the operating voltage of the detector D1.

In this embodiment, when the PMOS transistor M1 is required to be turned on, the control signal CTRL is a low voltage signal, so that the difference between the source voltage of the PMOS transistor M1 and the voltage of the control signal CTRL is greater than or equal to the turn-on voltage of the PMOS transistor M1; when the PMOS transistor M1 is required to be turned off, the control signal CTRL is a high voltage signal, so that the difference between the source voltage of the PMOS transistor M1 and the voltage of the control signal CTRL is smaller than the turn-on voltage of the PMOS transistor M1.

In a non-limiting embodiment, referring to fig. 6, unlike the embodiment shown in fig. 4, the selection module in this embodiment includes an NMOS transistor M2, the NMOS transistor M2 is connected in parallel with a capacitor C2, and a control terminal of the NMOS transistor M2 is connected to a control signal CTRL. Specifically, the source of the NMOS transistor M2 is coupled to the first end of the capacitor C2, the drain of the NMOS transistor M2 is coupled to the second end of the capacitor C2, and the gate of the NMOS transistor M2 is connected to the control signal CTRL. The NMOS transistor M2 may be controlled to be turned on and off by the control signal CTRL.

In particular, in the initial state, the NMOS transistor M2 is in a conductive state, that is, the control signal CTRL is a high voltage signal, so that the voltage difference between the voltage of the control signal CTRL (that is, the gate voltage of the NMOS transistor M2) and the source voltage of the NMOS transistor M2 is greater than or equal to the turn-on voltage of the NMOS transistor M2, and the voltage across the capacitor C2 is 0V. The detector D1, the capacitor C1 and the acquisition unit 401 may perform normal return light signal acquisition. Specifically, the electrical signal generated by the detector D1 is input to the acquisition unit 401 via the capacitor C1, and the acquisition unit 401 converts the electrical signal and outputs the converted electrical signal.

In specific implementation, when ambient light collection is required, the NMOS transistor M2 is controlled to be turned off by the control signal CTRL, that is, the control signal CTRL is a low voltage signal, so that the voltage difference between the voltage of the control signal CTRL and the source voltage of the NMOS transistor M2 is smaller than the turn-on voltage of the NMOS transistor M2. When the NMOS tube M2 is turned off, the turn-off time is set to t nanoseconds (ns), and the photocurrent responded by the detector D1 in the time charges the capacitor C2 and generates a voltage drop, and at this time, voltages across the capacitor C2 are different. Further, since the ambient photocurrent is a small direct current, it does not flow to the capacitor C1. After the turn-off time t nanoseconds, the NMOS tube M2 is turned on from off, the charge on the capacitor C2 is discharged to 0V, and a part of a pulse current signal (i.e., an ambient light integrated signal) generated by abrupt change of the voltage of the first end of the capacitor C2 is input to the acquisition unit 401 through the resistor R1 and the capacitor C1, and the acquisition unit 401 converts the signal and outputs the signal.

Accordingly, in a variation, referring to fig. 7, unlike the embodiment shown in fig. 6, the driving power source HV is positive voltage, and the voltage of the driving power source HV is greater than the voltage of the bias power source Vbias, so that the detector D1 has a reverse bias, and the voltage difference between the bias power source Vbias and the driving power source HV is the operating voltage of the detector D1. In addition, a first end of the capacitor C1 is coupled with an anode of the detector D1, and a cathode of the detector is connected with the driving power supply HV; the source of the NMOS tube M2 is coupled to the second end of the capacitor C2, the drain of the NMOS tube M2 is coupled to the first end of the capacitor C2, and the gate of the NMOS tube M2 is connected to the control signal CTRL.

In this embodiment, when the NMOS transistor M2 is required to be turned on, the control signal CTRL is a high voltage signal, so that the difference between the gate voltage of the NMOS transistor M2 and the source voltage of the NMOS transistor M2 is greater than or equal to the turn-on voltage of the NMOS transistor M2; when the NMOS transistor M2 is required to be turned off, the control signal CTRL is a low voltage signal, so that the difference between the source voltage of the NMOS transistor M2 and the voltage of the control signal CTRL is smaller than the turn-on voltage of the NMOS transistor M2.

In a non-limiting embodiment, please refer to fig. 8, unlike the embodiments shown in fig. 4 and 6, the selection module in this embodiment includes an analog switch M3. The analog switch M3 is connected in parallel with the capacitor C2, and a control end of the analog switch M3 is connected to the control signal CTRL. The NMOS transistor M2 may be controlled to be turned on and off by the control signal CTRL.

In this embodiment, the driving power source HV is a negative voltage, the bias power source Vbias is a positive voltage, the purpose is to make the detector D1 have a reverse bias, and the voltage difference between the bias power source Vbias and the driving power source HV is the operating voltage of the detector D1.

In particular, in the initial state, the analog switch M3 is in a conductive state, that is, the control signal CTRL controls the analog switch to perform state switching, so that the first end and the second end of the capacitor C2 are shorted, and at this time, the voltage across the capacitor C2 is 0V. The detector D1, the capacitor C1 and the acquisition unit 401 may perform normal return light signal acquisition. Specifically, the electrical signal generated by the detector D1 is input to the acquisition unit 401 via the capacitor C1, and the acquisition unit 401 converts the electrical signal and outputs the converted electrical signal.

In specific implementation, when ambient light collection is required, the control signal CTRL controls the analog switch to perform state switching, so that the first end and the second end of the capacitor C2 are shorted and disconnected, the turn-off time is set to t nanoseconds (ns), and then the photocurrent responded by the detector D1 in the time charges the capacitor C2 and generates voltage drop, and at this time, the voltages at the two ends of the capacitor C2 are different. Further, since the ambient photocurrent is a small direct current, it does not flow to the capacitor C1. After the turn-off time t nanoseconds, the analog switch is controlled again by the control signal CTRL to perform state switching so as to enable the first end and the second end of the capacitor C2 to be short-circuited, the charge on the capacitor C2 can be discharged to 0V, a part of pulse current signals (namely, ambient light integrated signals) generated by abrupt change of the voltage of the first end of the capacitor C2 are input to the acquisition unit 401 through the resistor R1 and the capacitor C1, and the acquisition unit 401 converts the signals and outputs the signals.

Accordingly, in a variation, referring to fig. 9, unlike the embodiment shown in fig. 8, the driving power source HV is positive voltage, and the voltage of the driving power source HV is greater than the voltage of the bias power source Vbias, so that the detector D1 has a reverse bias, and the voltage difference between the bias power source Vbias and the driving power source HV is the operating voltage of the detector D1. In addition, a first end of the capacitor C1 is coupled to an anode of the detector D1, and a cathode of the detector is connected to the driving power supply HV.

In one non-limiting embodiment, referring to fig. 10, fig. 10 shows a specific structure of a signal acquisition circuit. Unlike the signal acquisition modules of fig. 4-9, the signal acquisition module of the present embodiment further includes an amplifier 402.

Specifically, the capacitor C1 is coupled to the detector D1, and the detector D1 is connected to the driving power HV. The input of the amplifier 402 is coupled to the capacitor C1. An input terminal of the acquisition unit 402 is coupled to an output terminal of the amplifier 401, and an output terminal of the acquisition unit 401 outputs a measurement signal OUT.

It should be noted that, regarding the specific connection relationship between the detector D1 and the capacitor C1, reference may be made to the embodiment in which the driving power source HV is positive and negative in the foregoing embodiment, which is not described herein again.

In one non-limiting embodiment, referring to fig. 11, the signal acquisition method may include the steps of:

step 1101: the signal acquisition circuit is controlled to switch working modes, wherein the working modes comprise a return light signal acquisition mode and an ambient light measurement mode;

step 1102: if the working mode is the ambient light measurement mode, the integration module is controlled to integrate the electric signal generated by the detector and output an ambient light integration signal to the signal acquisition module, and the signal acquisition module acquires the ambient light integration signal;

step 1103: and if the working mode is the return light signal acquisition mode, controlling the electric signal generated by the detector to be output to the signal acquisition module, and acquiring the electric signal by the signal acquisition module.

Further, the control method of the ambient light measurement mode includes: opening an integration channel of the integration module; closing the integrating channel after the preset time;

the control method of the return light signal acquisition mode comprises the following steps: closing the integrating channel.

Further, when the ambient light measurement is performed, the selection module is determined to be switched to an ambient measurement mode; opening an integrating channel; controlling an integration module to integrate the electric signal generated by the detector within a preset time length; closing the integration channel, and controlling the integration module to output an integration signal. The signal acquisition module acquires the integrated signal and then outputs the integrated signal for calculating the subsequent ambient light.

When the return light signal is collected, the integrating channel is closed, an electric signal output by the detector enters the signal collecting module, and the signal collecting module collects the electric signal and is used for calculating the detection distance after being output.

It will be appreciated that in a specific implementation, the signal acquisition method may be implemented in a software program running on a processor integrated within a chip or a chip module. The method may also be implemented by combining software with hardware, which is not limited in this application.

The steps of the signal acquisition method of the present embodiment may be performed by an FPGA. Namely, the FPGA controls the ambient light acquisition circuit to acquire ambient light or return light signals.

In this embodiment, the step 1102 and the step 1103 are not performed simultaneously, and one of the steps 1102 and 1103 may be selectively performed. Specifically, when ambient light needs to be measured, step 1102 is performed; when the return light signal needs to be measured, step 1103 is performed.

For more specific embodiments of the signal acquisition method, please refer to the foregoing embodiments, and the description thereof is omitted herein.

The embodiment of the invention also discloses a laser radar, which comprises at least one detector. The laser radar also comprises the signal acquisition circuit. The signal acquisition circuit may acquire an ambient light or return light signal acquired by the at least one detector.

It should be understood that the term "and/or" is merely an association relationship describing the associated object, and means that three relationships may exist, for example, a and/or B may mean: a exists alone, A and B exist together, and B exists alone. In this context, the character "/" indicates that the front and rear associated objects are an "or" relationship.

The term "plurality" as used in the embodiments of the present invention means two or more.

The first, second, etc. descriptions in the embodiments of the present invention are only used for illustrating and distinguishing the description objects, and no order is used, nor is the number of the devices in the embodiments of the present invention limited, and no limitation on the embodiments of the present invention should be construed.

The "connection" in the embodiment of the present invention refers to various connection manners such as direct connection or indirect connection, so as to implement communication between devices, which is not limited in the embodiment of the present invention.

The above embodiments may be implemented in whole or in part by software, hardware, firmware, or any other combination. When implemented in software, the above-described embodiments may be implemented in whole or in part in the form of a computer program product. The computer program product comprises one or more computer instructions or computer programs. When the computer instructions or computer program are loaded or executed on a computer, the processes or functions described in accordance with embodiments of the present invention are produced in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from one website site, computer, server, or data center to another website site, computer, server, or data center by wired or wireless means. The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains one or more sets of available media.

In the several embodiments provided in the present application, it should be understood that the disclosed method, apparatus, and system may be implemented in other manners. For example, the device embodiments described above are merely illustrative; for example, the division of the units is only one logic function division, and other division modes can be adopted in actual implementation; for example, multiple units or components may be combined or may be integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in the embodiments of the present invention may be integrated in one processing unit, or each unit may be physically included separately, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in hardware plus software functional units.

The integrated units implemented in the form of software functional units described above may be stored in a computer readable storage medium. The software functional unit is stored in a storage medium, and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform part of the steps of the method according to the embodiments of the present invention.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention should be assessed accordingly to that of the appended claims.

Claims (15)

1. A signal acquisition circuit for a lidar, the signal acquisition circuit comprising: the system comprises a detector, a selection module, an integration module and a signal acquisition module;

the selection module is coupled with the integration module and is used for controlling the signal acquisition circuit to switch working modes, wherein the working modes comprise a return light signal acquisition mode and an ambient light measurement mode;

the integration module is coupled with the detector and the selection module and is used for integrating the electric signal generated by the detector in an ambient light measurement mode and outputting an ambient light integration signal;

The input end of the signal acquisition module is coupled with the detector and the integration module and is used for acquiring an electric signal generated by the detector in the return light signal acquisition mode or acquiring the ambient light integration signal in the ambient light measurement mode.

2. The signal acquisition circuit of claim 1 wherein in the ambient light measurement mode, the integration module integrates the electrical signal generated by the detector and outputs the ambient light integrated signal to the signal acquisition module, which acquires the ambient light integrated signal.

3. The signal acquisition circuit of claim 1, wherein in the return signal acquisition mode, the electrical signal generated by the detector is output to the signal acquisition module, which acquires the electrical signal.

4. The signal acquisition circuit of claim 1, wherein the integration module comprises: and the first end of the integration unit is connected with the electric signal generated by the detector, the second end of the integration unit is connected with a bias power supply, and the integration unit is used for integrating the electric signal generated by the detector in the ambient light measurement mode.

5. The signal acquisition circuit of claim 4 wherein the integration module further comprises: the first end of the impedance unit is coupled with the second end of the detector, the second end of the impedance unit is coupled with the first end of the integration unit, and the impedance unit is used for blocking the electric signal from being input into the integration unit in the return light signal acquisition mode and enabling the electric signal to be input into the integration unit in the ambient light measurement mode.

6. The signal acquisition circuit of claim 5 wherein the impedance unit has a first impedance and the signal acquisition module has a second impedance, the first impedance being greater than the second impedance in the return signal acquisition mode; in the ambient light measurement mode, the first impedance is less than the second impedance.

7. The signal acquisition circuit of claim 4 wherein in the return signal acquisition mode, the selection module shorts the first and second ends of the integration unit; in the ambient light measurement mode, the selection module enables the first end and the second end of the integration unit to be in non-short connection, and enables the first end and the second end of the integration unit to be in short connection after a preset time length.

8. The signal acquisition circuit of claim 7, wherein the selection module comprises:

any one of a PMOS tube, an NMOS tube and an analog switch;

the PMOS tube is connected in parallel with the integration unit, and the control end of the PMOS tube is connected with a control signal; the NMOS tube is connected in parallel with the integration unit, and the control end of the NMOS tube is connected with a control signal;

the analog switch is connected with the integration unit in parallel, and the control end of the analog switch is connected with a control signal.

9. The signal acquisition circuit of claim 1, wherein the signal acquisition module comprises:

the first end of the capacitor is coupled with the second end of the detector, and the first end of the detector is connected with a driving power supply;

the input end of the acquisition unit is coupled with the second end of the capacitor, and the output end of the acquisition unit outputs a measuring signal.

10. The signal acquisition circuit of claim 1, wherein the signal acquisition module comprises:

the first end of the capacitor is coupled with the second end of the detector, and the first end of the detector is connected with a driving power supply;

an amplifier, an input end of the amplifier is coupled with a second end of the capacitor;

The input end of the acquisition unit is coupled with the output end of the amplifier, and the output end of the acquisition unit outputs a measuring signal.

11. A signal acquisition method for a lidar, comprising:

the signal acquisition circuit is controlled to switch working modes, wherein the working modes comprise a return light signal acquisition mode and an ambient light measurement mode;

if the working mode is the ambient light measurement mode, the integration module is controlled to integrate the electric signal generated by the detector and output an ambient light integration signal to the signal acquisition module, and the signal acquisition module acquires the ambient light integration signal;

and if the working mode is the return light signal acquisition mode, controlling the electric signal generated by the detector to be output to the signal acquisition module, and acquiring the electric signal by the signal acquisition module.

12. The signal acquisition method according to claim 11, wherein the control method of the ambient light measurement mode comprises:

opening an integration channel of the integration module;

and closing the integrating channel after the preset time.

13. The method of claim 12, wherein the operating mode is the ambient light measurement mode, and controlling the integration module to integrate the electrical signal generated by the detector and output the ambient light integrated signal to the acquisition module comprises:

The selection module is switched to an ambient light measurement mode;

opening the integration channel, and controlling the integration module to integrate the electric signal generated by the detector within a preset time length;

and closing the integration channel, and controlling the integration module to output an integration signal.

14. The signal acquisition method according to claim 11, wherein the control method of the return signal acquisition mode includes: closing the integrating channel.

15. A lidar comprising a signal acquisition circuit for a lidar according to any of claims 1 to 10.