WO2020142920A1

WO2020142920A1 - Signal amplification method and device, distance measuring device

Info

Publication number: WO2020142920A1
Application number: PCT/CN2019/070956
Authority: WO
Inventors: 刘祥; 马亮亮
Original assignee: 深圳市大疆创新科技有限公司
Priority date: 2019-01-09
Filing date: 2019-01-09
Publication date: 2020-07-16
Also published as: CN111684300B; CN111684300A

Abstract

A signal amplification method (100) and device. The method (100) comprises: emitting an optical pulse signal (S110); receiving by an optical conversion module the optical pulse signal reflected by an object and converting the optical pulse signal into an electrical pulse signal (S120); and amplifying the electrical pulse signal by an amplification module (S130); wherein the amplification gain of the optical conversion module differs at at least some moments between the transmitting moment of an optical pulse and the receiving moment of the reflected optical pulse signal, and/or the amplification gain of the amplification module differs at at least some moments, and the reflected optical pulse signal is amplified by different multiples so as to solve the problem that information is lost or still unable to be detected after the reflected optical pulse signal is amplified, thereby facilitating improving the effectiveness and reliability of subsequent signal processing.

Description

Signal amplification method and device, and distance measuring device

Technical field

The present invention relates to the field of circuit technology, and in particular, to a signal amplification method and device.

Background technique

Lidar and laser ranging are perception systems for the outside world, which can learn the spatial distance information in the direction of launch. The principle is to actively emit a laser pulse signal to the outside, detect the reflected pulse signal, and judge the distance of the measured object according to the time difference between transmission and reception. In the process of measuring the relative distance of the target by measuring the round-trip time of the optical pulse sequence, the power of the optical pulse sequence reflected by the target will be violent due to the change in the target distance and reflection characteristics of the measured target in a large dynamic range. Variation, for example, in the vicinity of 0.1m and the distance of 50m, the difference of the reflected signal strength can reach 10 ⁴ ˉ10 ⁵ level. If all the reflected light pulse signals are amplified with the same magnification, it will cause Part of the information of the signal is lost and some signals cannot be detected.

Summary of the invention

Embodiments of the present invention provide a signal amplification method to solve the problem that information is lost or still cannot be detected after the reflected light pulse signal is amplified.

In a first aspect, an embodiment of the present invention provides a signal amplification method, including:

Emit light pulse signal;

Receiving the optical pulse signal reflected by the object through the optical conversion module, and converting the optical pulse signal into an electrical pulse signal;

Amplify the electrical pulse signal through an amplification module;

Wherein, between the time of transmitting the optical pulse and the time of receiving the reflected optical pulse signal, the amplification gain of the optical conversion module is different at least part of the time, and/or the amplification gain of the amplification module is At least part of the time is different.

On the other hand, an embodiment of the present invention provides a signal amplification device, including:

Transmitting module, used to transmit optical pulse signal;

The light conversion module is used to receive the light pulse signal reflected by the object and convert the light pulse signal into an electrical pulse signal;

An amplification module for amplifying the electrical pulse signal;

On the other hand, an embodiment of the present invention provides a distance measuring device, the distance measuring device is configured to determine the object and the object according to the transmitted light pulse signal and the received light pulse signal reflected by the object The distance of the distance measuring device; the distance measuring device includes the above-mentioned signal amplifying device.

In the signal amplification method of the embodiment of the present invention, the reflected light pulse signal is amplified by different multiples according to the difference in the flight time of the reflected light pulse signal, so as to solve the problem that the reflected light pulse signal is amplified or the information is lost or still Problems that cannot be detected, ensuring that the reflected optical pulse signal is amplified with an appropriate magnification factor, is conducive to improving the effectiveness and reliability of subsequent signal processing.

BRIEF DESCRIPTION

In order to more clearly explain the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, without paying any creative work, other drawings can be obtained based on these drawings.

FIG. 1 is a schematic flowchart of a signal amplification method according to an embodiment of the present invention;

2 is an example of the amplification gain of the optical conversion module and/or the amplification gain of the amplification module changing with time according to an embodiment of the present invention;

3 is another example of the amplification gain of the optical conversion module and/or the amplification gain of the amplification module changing with time according to an embodiment of the present invention;

4 is an example of an RC integration circuit of an embodiment of the present invention;

5 is an example of controlling the feedback resistance of a variable gain amplifier according to an embodiment of the present invention;

6 is a schematic diagram of a pulse sequence of emitted light according to an embodiment of the present invention;

7 is a schematic block diagram of a signal amplification method according to an embodiment of the present invention;

8 is a schematic structural block diagram of a distance measuring device according to an embodiment of the present invention;

9 is a schematic diagram of an embodiment of the distance measuring device of the present invention using a coaxial optical path.

detailed description

The technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention.

In order to realize the detection of a wide dynamic range, the light pulse signal reflected by the target object in the vicinity can be amplified with a small amplification factor, so as not to be limited and lose part of the information; for the target object in the distance The reflected optical pulse signal can be amplified at a larger magnification due to the smaller optical pulse signal, and the weak photoelectric signal can be amplified enough to prevent it from being detected and can be digitized smoothly.

Based on the above considerations, an embodiment of the present invention provides a signal amplification method. Referring to FIG. 1, FIG. 1 shows a signal amplification method according to an embodiment of the present invention. The method 100 includes:

In step S110, an optical pulse signal is emitted;

In step S120, receiving the optical pulse signal reflected by the object through the optical conversion module, and converting the optical pulse signal into an electrical pulse signal;

In step S130, the electrical pulse signal is amplified by an amplification module;

Since the target object is located in the vicinity, when the optical pulse signal is transmitted, it reaches the target object and is reflected back soon. The time from the transmission to the reception of the optical pulse signal is relatively short, and the loss of the optical pulse signal during this flight time Less, the intensity of the optical pulse signal reflected by the optical conversion module received by the target object is greater, and only this larger optical pulse signal needs to be amplified with a smaller gain at this time; when the target object is located at a distance, it is transmitted from The time to receive the optical pulse signal is relatively long, and the loss of the optical pulse signal during this flight time is large. The intensity of the optical pulse signal received by the optical conversion module after passing through the target object is small, and a large gain is required at this time. Amplify this larger light pulse signal; it can be seen that the intensity of the light pulse signal reflected by the object decreases with the increase of the flight time, and accordingly different amplification gains are required to amplify the reflected light pulse signal The amplification gain changes with the time of flight of the optical pulse signal. In this way, it can be ensured that the reflected optical pulse signal can be amplified to an appropriate multiple, which is beneficial to improve the accuracy of the subsequent digital processing of the signal.

It should be noted that the optical conversion module can convert the optical pulse signal into an electrical pulse signal, which can also have an amplification function, that is, it can also amplify the converted electrical pulse signal, and whether the optical pulse signal reflected by the object passes through the light The conversion module performs amplification without limitation.

Optionally, the method 100 further includes: controlling the amplification gain of the light conversion module and/or the amplification gain of the amplification module so that the amplification of the light conversion module and/or the amplification module at the first moment The gain is greater than the amplification gain at the second moment, where both the first moment and the second moment are between the moment of transmission of the optical pulse and the moment of reception of the reflected optical pulse signal, and the first moment is later than the second time.

Wherein, the intensity of the reflected optical pulse signal changes with the flight time, therefore, the amplification gain of the reflected optical pulse signal (including the amplification gain of the optical conversion module and/or Or the amplification gain of the amplification module), the reflected optical pulse signals received at different times are amplified with an appropriate amplification gain.

Optionally, the controlling the amplification gain of the optical conversion module and/or the amplification gain of the amplification module includes:

Controlling the amplification gain of the optical conversion module and/or the amplification gain of the amplification module to gradually increase between the transmission time of the optical pulse and the reception time of the reflected optical pulse signal.

Because the intensity of the generally reflected optical pulse signal is inversely proportional to the time of flight, then you can start from transmitting the optical pulse signal. With the flight of the optical pulse signal, the intensity of the optical pulse signal gradually decreases, and its amplification gain can be controlled to gradually increase. For example, if the distance L _A between the target object A and the position of the emitted light pulse signal is longer than the distance L _B between the target object B and the position of the emitted light pulse signal, then the amplification gain of the light pulse signal reflected by the target object A is less than that of the target object B The amplification gain of the optical pulse signal.

Then, the amplification gain of the light conversion module and/or the amplification gain of the amplification module and the distance between the flight time and the target object may be linear or non-linear.

The amplification gain of the optical conversion module and/or the amplification gain of the amplification module is controlled to increase linearly between the transmission time of the optical pulse and the reception time of the reflected optical pulse signal.

Referring to FIG. 2, FIG. 2 shows an example of the amplification gain of the optical conversion module of the embodiment of the present invention and/or the amplification gain of the amplification module changing with time. As shown in Fig. 2, the amplification gain has an initial value at the moment of emission of the optical pulse, which increases linearly with time/distance.

The amplification gain of the optical conversion module and/or the amplification gain of the amplification module is controlled to increase between the transmission time of the optical pulse and the reception time of the reflected optical pulse signal, and the growth rate is gradually accelerated.

Referring to FIG. 3, FIG. 3 shows another example of the amplification gain of the optical conversion module of the embodiment of the present invention and/or the amplification gain of the amplification module changing with time. In general, the intensity of the light pulse signal reflected back from the target object is inversely proportional to L ² , where L is the distance between the target object and the position of the emitted light pulse signal. As shown in FIG. 3, the amplification gain has an initial value at the moment of emission of the optical pulse, and the increase rate increases exponentially as time/distance increases gradually.

Optionally, the amplification module includes a variable gain amplifier, and the controlling the amplification gain of the amplification module includes:

The voltage of the variable gain amplifier is controlled by an RC integration circuit so that the voltage of the variable gain amplifier gradually increases.

Referring to FIG. 4, FIG. 4 shows an example of an RC integration circuit according to an embodiment of the present invention. As shown in FIG. 4, the RC integration circuit includes a resistor R and a capacitor C, one end of the resistor R receives the trigger signal Start, and the other end of the resistor R is connected to one end of the capacitor C and outputs a gain control signal Gain Control Signal, the other end of the capacitor C is grounded. Its working principle includes: the trigger signal StartSignal and the emitted light pulse signal can be a step signal at the same time, when the RC integration circuit receives the trigger signal StartSignal, the RC integration circuit starts integration, and outputs the gain control signal Gain Control Signal, which controls the voltage of the variable gain amplifier to gradually increase; when receiving the optical pulse signal reflected by the object, the reflected optical pulse signal is amplified with the amplification gain at this time.

From the moment of transmission of the optical pulse signal, the amplification gain of the optical conversion module and/or the amplification module is controlled to increase from the initial value.

The initial value of the amplification gain may be 0 or a certain value, which is not limited herein.

Controlling the amplification gain of the optical conversion module and/or the amplification gain of the amplification module to increase stepwise between the transmission time of the optical pulse and the reception time of the reflected optical pulse signal.

In some embodiments, after transmitting the optical pulse signal, there are several time periods. In each of the same time period, the intensity of the received reflected optical pulse signal is not much different, and it is not necessary to use the amplification gain that changes from moment to moment. Stepwise growth is used to achieve the same amplification gain in the same time period, and the amplification gain is different between different time periods, which is beneficial to the realization of amplification gain control, and improves the operation efficiency, and realizes the rapid and accurate amplification of the optical pulse signal .

It should be noted that the amplification gain of the optical conversion module and/or the change of the amplification gain of the amplification module are not limited to the above-mentioned cases, but may also be other at the time of transmission and reception of the optical pulse signal Conditions that are at least partly different from time to time, such as the growth rate gradually becoming slower, are not limited here.

Optionally, the amplification module includes a variable gain amplifier or a programmable gain amplifier.

Optionally, the amplification module includes a variable gain amplifier, and the method further includes:

The feedback resistance of the variable gain amplifier is controlled to change the amplification gain of the variable gain amplifier.

Wherein, when the amplifying module includes a variable gain amplifier (VGA, variable gains), the amplification gain of the variable gain amplifier can be controlled by controlling the output voltage of the variable gain amplifier. The integrating RC circuit provided in the embodiment can also control the amplification gain of the variable gain amplifier by controlling the DAC (Digital to Analog Converter) and the feedback resistance of the variable gain amplifier.

In one embodiment, referring to FIG. 5, FIG. 5 shows an example of controlling the feedback resistance of the variable gain amplifier according to an embodiment of the present invention. As shown in FIG. 5, the variable gain amplifier includes a resistor R1, an operational amplifier U1, and a digital potentiometer. One end of the resistor R1 receives an input signal Signal_in, and the other end of the resistor R1 is connected to the operational amplifier U1. Inverting input terminal -IN, the positive input terminal +IN of the operational amplifier U1 is connected to the reference voltage AMP_REF, the output terminal OUT of the operational amplifier U1 outputs the amplified signal Out_signal, and the digital potentiometer is connected to the operational Between the inverting input terminal -IN of the amplifier U1 and the output terminal OUT of the operational amplifier U1. Among them, the resistance of the digital potentiometer can be adjusted, the amplification gain of the variable gain amplifier can be controlled by controlling the resistance of the digital potentiometer; and the digital potentiometer can also be other adjustable resistance devices, such as working in the linear region MOS tube etc.

Optionally, the method further includes:

A sequence of optical pulses is emitted, and the interval between two adjacent optical pulses is at least 10 times longer than the longest detection duration, where the longest detection duration is the smallest detectable optical pulse signal reflected by an object The detection time is the interval between the corresponding light pulse emission time.

Wherein, the light pulse sequence may be emitted by an emission light source, and the laser pulse sequence emitted by the emission light source is changed by the scanning module (for example, a rotating prism) to form laser beams with multiple exit paths at different times Pulse sequence. The light pulse sequence may also be emitted by multiple emission light sources along different exit paths, and the different exit paths may be different exit positions and/or exit directions. The multiple laser pulse sequences emitted by the multiple emission light sources may be parallel or non-parallel. The laser pulse sequences respectively emitted by the multiple emitting light sources can be emitted by the scanning module (for example, a rotating prism) after changing the propagation direction.

In the light pulse sequence, in a working cycle, the time required for the distance from the emitted light pulse to the calculation of the position of the target object and the emitted light pulse signal is t. The specific size of t depends on the distance between the target object detected by the optical pulse and the position where the optical pulse signal is emitted. The farther the distance, the greater t. When the target object is farther away from the position where the optical pulse signal is emitted, the weaker the optical signal reflected back by the object. When the reflected optical signal is weak to a certain degree, the optical signal cannot be detected. Therefore, the distance between the object corresponding to the weakest light signal that can be detected and the position where the light pulse signal is emitted is called the farthest detection distance. For convenience of description, the t value corresponding to the furthest detection distance is called t0. In the embodiment of the present invention, the duty cycle is greater than t0. In some implementations, the duty cycle is greater than at least 5 times t0. In some implementations, the duty cycle is greater than at least 10 times t0. In some implementations, the duty cycle is greater than 15 times t0. In some implementations, t0 is in the nanosecond level, and the duty cycle is in the microsecond level.

In one embodiment, referring to FIG. 6, FIG. 6 shows a schematic diagram of a light emission pulse sequence according to an embodiment of the present invention. As shown in FIG. 6, the transmitting circuit emits an optical pulse sequence at time a1. After the optical pulse sequence is processed by the receiving circuit, the sampling circuit, and the arithmetic circuit in sequence, the calculation result is obtained at time b1, and the duration between time a1 and time b1 is t1 ; Then, the transmitting circuit emits an optical pulse sequence at time a2, the optical pulse sequence is processed by the receiving circuit, the sampling circuit, and the arithmetic circuit in sequence, and the calculation result is obtained at time b2, and the duration between time a2 and time b2 is t2; then, The transmitting circuit emits an optical pulse sequence at time a3. The optical pulse sequence is processed by the receiving circuit, the sampling circuit, and the arithmetic circuit in sequence, and the calculation result is obtained at time b3, and the duration between time a3 and time b3 is t3. It can be understood that the durations of t1, t2, and t3 are respectively less than or equal to the aforementioned t0. In the example shown in FIG. 6, a2 is later than b1, a3 is later than b2; the duration between a1 and a2 and the duration between a2 and a3 are the same duration P, and the duration P is the above-mentioned duty cycle.

Optionally, the method further includes:

Starting to control the amplification gain of the optical conversion module and/or the amplification gain of the amplification module to increase from the initial value at the emission timing of at least part of the optical pulses in the optical pulse sequence, respectively;

After the longest detection duration is reached from the emission time of the at least part of the optical pulses respectively, the amplification gain of the optical conversion module and/or the amplification gain of the amplification module are stopped from increasing.

Wherein, for the emission interval between the optical pulses in the optical pulse sequence is much greater than the time from the optical pulse to the farthest detection distance, then the amplification gain and/or the optical conversion module can be controlled at the moment of the optical pulse emission The amplification gain of the amplification module begins to increase from the initial value; since the farthest distance that the optical pulse can detect is known, that is, the time from the emission of the optical pulse to the farthest detection distance is also known, then from the optical pulse to the calculation after the optical pulse After the longest detection distance takes t0, the optical pulse must have returned and processed by the receiving circuit, the sampling circuit, and the arithmetic circuit to obtain the operation result. At this time, the increase of the amplification gain can be stopped. When the next optical pulse is emitted, the amplification gain of the optical conversion module and/or the amplification gain of the amplification module are increased from the initial value again, and so on, all the optical pulses of the optical pulse sequence can be Amplify with appropriate amplification gain.

In addition, it is also possible to control the amplification gain of the optical conversion module and/or the amplification gain of the amplification module to stop increasing at the receiving moment of the at least part of the optical pulses, respectively.

In one embodiment, referring to FIG. 7, FIG. 7 shows a schematic block diagram of a signal amplification method according to an embodiment of the present invention. With reference to FIG. 6 and FIG. 7, a signal amplification method according to an embodiment of the present invention will be further described with specific examples.

As shown in FIG. 7, the transmitting circuit 710 is used to transmit an optical pulse signal; the optical conversion module includes a photoelectric sensor 720 for receiving the optical pulse signal reflected by the object, and converting the optical pulse signal into an electrical pulse signal; an amplifying circuit 730 amplify the electrical pulse signal; wherein, between the time of transmission of the light pulse and the time of reception of the reflected light pulse signal, the amplification gain of the photosensor 720 differs at least in part, and/ Or, the amplification gain of the amplification circuit 730 is different at least part of the time;

The central control circuit 740 is used to send a transmission control signal to the transmission circuit 710 to control the transmission circuit 710 to emit an optical pulse signal; and to control the amplification gain of the photosensor 720 and/or the amplification circuit 730;

The digitizing circuit 750 is used to digitize the output signal of the amplifying circuit 730 to provide a data basis for the subsequent calculation of the distance of the target object.

6 and 7, it is assumed that the central control circuit 740 sends a transmission control signal to the transmission circuit 710, the transmission circuit 710 transmits the first optical pulse signal at time a1, and at the same time, the central control circuit 740 controls the photoelectric sensor 720 And/or the amplification gain of the amplification circuit 730 starts to increase from the initial value; the first optical pulse signal returns after being reflected by the object, and the photoelectric sensor 720 receives the first optical pulse signal reflected by the object and converts it into The first electrical pulse signal, the photosensor 720 and/or the amplifying circuit 730 amplifies the first electrical pulse signal with an amplification gain that increases from the initial value to this time; the digitizing circuit 750 performs the output signal of the amplifying circuit 730 Digitize and sample, and then send the digitized and sampled results to the arithmetic circuit for calculation. The arithmetic circuit obtains the arithmetic result at time b1 after the operation. The duration between time a1 and time b1 is t1; when it starts from time a1, the After an electrical pulse signal is transmitted to the time t0 required to calculate the farthest detection distance of the first electrical pulse signal, the central control circuit 740 stops controlling the increase of the amplification gain of the photoelectric sensor 720 and/or the amplification circuit 730; where t0 is greater than or Is equal to t1.

Suppose that the emission time interval (ie, the working period P) of two adjacent optical pulses is greater than at least 10 times the longest detection time t0. Then, when the optical pulse is emitted for the second time, the first optical pulse signal has reached the target object and returned, After calculation, the calculation result is obtained, and the second light pulse emitted and the first light pulse will not cause mutual influence. After the duty cycle P from time a1, the central control circuit 740 sends a transmission control signal to the transmission circuit 710. The transmission circuit 710 transmits the second light pulse signal at time a2, and at the same time, the central control circuit 740 controls the photoelectric sensor 720 and/or the amplification gain of the amplifying circuit 730 starts to increase from the initial value again; similarly, the second optical pulse signal returns after being reflected by the object, and after being converted into the second electric pulse signal by the photoelectric sensor 720, the photoelectric sensor 720 and/or the amplifying circuit 730 amplifies the second electrical pulse signal with an amplification gain that increases from the initial value to this time; and then, after digitization, sampling, and operation, the operation result is obtained at time b2, between time a2 and time b2 The duration of time is t2; when starting from time a2, after the time t0 from the first electrical pulse signal transmission to the calculation of the farthest detection distance of the first electrical pulse signal is calculated, the central control circuit 740 stops controlling the photoelectric sensor 720 and/or Or, the amplification gain of the amplification circuit 730 increases.

By analogy, each light pulse signal can be amplified by an appropriate amplification gain after being reflected by the object, which is beneficial to improve the accuracy of the subsequent calculation process.

Optionally, the method is applied to a distance measuring device, and the method further includes:

The distance between the object and the distance measuring device is determined according to the transmitted optical pulse signal and the received optical pulse signal reflected by the object.

Optionally, the method further includes:

Emitting light pulse sequence;

The scanning module is used to change the exit direction of the optical pulse sequence, so that each optical pulse in the optical pulse sequence is sequentially emitted to different directions.

Optionally, the scanning module includes at least two rotating light refracting elements with non-parallel exit surfaces and entrance surfaces.

The signal amplification methods provided by various embodiments of the present invention may be applied to a distance measuring device, and the distance measuring device may be an electronic device such as a laser radar or a laser distance measuring device. In one embodiment, the distance measuring device is used to sense external environment information, for example, distance information, azimuth information, reflection intensity information, speed information, etc. of the environmental target. In an implementation manner, the distance measuring device can detect the distance between the detecting object and the distance measuring device by measuring the time of light propagation between the distance measuring device and the detection object, that is, Time-of-Flight (TOF). Alternatively, the distance measuring device may also detect the distance between the detected object and the distance measuring device through other techniques, such as a distance measuring method based on phase shift measurement, or a distance measuring method based on frequency shift measurement. There are no restrictions.

For ease of understanding, the following describes the working process of distance measurement in conjunction with the distance measurement device 800 shown in FIG. 8.

As shown in FIG. 8, the distance measuring device 800 may include a transmitting circuit 810, a receiving circuit 820, a sampling circuit 830 and an arithmetic circuit 840.

The transmitting circuit 810 may transmit a sequence of light pulses (for example, a sequence of laser pulses). The receiving circuit 820 can receive the optical pulse sequence reflected by the detected object, and photoelectrically convert the optical pulse sequence to obtain an electrical signal, which can be output to the sampling circuit 830 after processing the electrical signal. The sampling circuit 830 may sample the electrical signal to obtain the sampling result. The arithmetic circuit 840 may determine the distance between the distance measuring device 800 and the detected object based on the sampling result of the sampling circuit 830.

Optionally, the distance measuring device 800 may further include a control circuit 850, which can control other circuits, for example, can control the working time of each circuit and/or set parameters for each circuit.

It should be understood that although the distance measuring device shown in FIG. 8 includes a transmitting circuit, a receiving circuit, a sampling circuit, and an arithmetic circuit for emitting a beam of light for detection, the embodiments of the present application are not limited thereto, and the transmitting circuit , The number of any one of the receiving circuit, the sampling circuit, and the arithmetic circuit may also be at least two, for emitting at least two light beams in the same direction or respectively in different directions; wherein, the at least two light paths may be simultaneously The shot may be shot at different times. In one example, the light-emitting chips in the at least two emission circuits are packaged in the same module. For example, each emitting circuit includes a laser emitting chip, and the die in the laser emitting chips in the at least two emitting circuits are packaged together and housed in the same packaging space.

In some implementations, in addition to the circuit shown in FIG. 8, the distance measuring device 800 may further include a scanning module 860 for changing the propagation direction of at least one laser pulse sequence emitted from the transmitting circuit.

Among them, the module including the transmitting circuit 810, the receiving circuit 820, the sampling circuit 830, and the arithmetic circuit 840, or the module including the transmitting circuit 810, the receiving circuit 820, the sampling circuit 8830, the arithmetic circuit 840, and the control circuit 850 may be called a measurement A distance module, the distance measuring module may be independent of other modules, for example, the scanning module 860.

A coaxial optical path may be used in the distance measuring device, that is, the light beam emitted by the distance measuring device and the reflected light beam share at least part of the optical path in the distance measuring device. For example, after at least one laser pulse sequence emitted by the transmitting circuit is emitted by the scanning module to change the propagation direction, the laser pulse sequence reflected by the detection object passes through the scanning module and enters the receiving circuit. Alternatively, the distance measuring device may also adopt an off-axis optical path, that is, the light beam emitted from the distance measuring device and the reflected light beam are respectively transmitted along different optical paths in the distance measuring device. 9 shows a schematic diagram of an embodiment of the distance measuring device of the present invention using a coaxial optical path.

The distance measuring device 900 includes a distance measuring module 910, and the distance measuring module 910 includes a transmitter 903 (which may include the above-mentioned transmitting circuit), a collimating element 904, and a detector 905 (which may include the above-mentioned receiving circuit, sampling circuit, and arithmetic circuit) and Optical path changing element 906. The ranging module 910 is used to emit a light beam, and receive back light, and convert the back light into an electrical signal. Among them, the transmitter 903 may be used to transmit a light pulse sequence. In one embodiment, the transmitter 903 may emit a sequence of laser pulses. Optionally, the laser beam emitted by the transmitter 903 is a narrow-bandwidth beam with a wavelength outside the visible light range. The collimating element 904 is disposed on the exit optical path of the emitter, and is used to collimate the light beam emitted from the emitter 903, and collimate the light beam emitted from the emitter 903 into parallel light to the scanning module. The collimating element is also used to converge at least a part of the return light reflected by the detection object. The collimating element 904 may be a collimating lens or other element capable of collimating the light beam.

In the embodiment shown in FIG. 9, the optical path changing element 906 is used to combine the transmitting optical path and the receiving optical path in the distance measuring device before the collimating element 904, so that the transmitting optical path and the receiving optical path can share the same collimating element, so that the optical path More compact. In some other implementation manners, the transmitter 903 and the detector 905 may respectively use respective collimating elements, and the optical path changing element 906 is disposed on the optical path behind the collimating element.

In the embodiment shown in FIG. 9, since the beam aperture of the light beam emitted by the transmitter 903 is small and the beam aperture of the returned light received by the distance measuring device is large, the light path changing element can use a small-area mirror to change The transmitting optical path and the receiving optical path are combined. In some other implementations, the light path changing element may also use a reflective mirror with a through hole, where the through hole is used to transmit the outgoing light of the emitter 903, and the reflective mirror is used to reflect the return light to the detector 905. In this way, it is possible to reduce the blocking of the return light by the support of the small mirror in the case of using the small mirror.

In the embodiment shown in FIG. 9, the optical path changing element is offset from the optical axis of the collimating element 904. In some other implementations, the optical path changing element may also be located on the optical axis of the collimating element 904.

The distance measuring device 900 further includes a scanning module 902. The scanning module 902 is placed on the exit optical path of the distance measuring module 910. The scanning module 902 is used to change the transmission direction of the collimated light beam 919 emitted through the collimating element 904 and project it to the external environment, and project the return light to the collimating element 904 . The returned light is converged on the detector 905 via the collimating element 904.

In one embodiment, the scanning module 902 may include at least one optical element for changing the propagation path of the light beam, wherein the optical element may change the propagation path of the light beam by reflecting, refracting, diffracting, etc. the light beam. For example, the scanning module 902 includes lenses, mirrors, prisms, galvanometers, gratings, liquid crystals, optical phased arrays (Optical Phased Array), or any combination of the above optical elements. In one example, at least part of the optical element is moving, for example, the at least part of the optical element is driven to move by a driving module, and the moving optical element can reflect, refract or diffract the light beam to different directions at different times. In some embodiments, multiple optical elements of the scanning module 902 may rotate or vibrate about a common axis 909, and each rotating or vibrating optical element is used to continuously change the direction of propagation of the incident light beam. In one embodiment, the multiple optical elements of the scanning module 902 can rotate at different rotation speeds, or vibrate at different speeds. In another embodiment, at least part of the optical elements of the scanning module 902 can rotate at substantially the same rotational speed. In some embodiments, the multiple optical elements of the scanning module may also rotate around different axes. In some embodiments, the multiple optical elements of the scanning module may also rotate in the same direction, or rotate in different directions; or vibrate in the same direction, or vibrate in different directions, which is not limited herein.

In one embodiment, the scanning module 902 includes a first optical element 914 and a drive 916 connected to the first optical element 914. The drive 916 is used to drive the first optical element 914 to rotate about a rotation axis 909 to change the first optical element 914 Collimate the direction of beam 919. The first optical element 914 projects the collimated light beam 919 in different directions. In one embodiment, the angle between the direction of the collimated light beam 919 changed by the first optical element and the rotation axis 909 changes as the first optical element 914 rotates. In one embodiment, the first optical element 914 includes a pair of opposed non-parallel surfaces through which the collimated light beam 919 passes. In one embodiment, the first optical element 914 includes a prism whose thickness varies along at least one radial direction. In one embodiment, the first optical element 914 includes a wedge-angle prism that aligns the straight beam 919 for refraction.

In one embodiment, the scanning module 902 further includes a second optical element 915. The second optical element 915 rotates around a rotation axis 909. The rotation speed of the second optical element 915 is different from the rotation speed of the first optical element 914. The second optical element 915 is used to change the direction of the light beam projected by the first optical element 914. In one embodiment, the second optical element 915 is connected to another driver 917, and the driver 917 drives the second optical element 915 to rotate. The first optical element 914 and the second optical element 915 may be driven by the same or different drivers, so that the rotation speed and/or rotation of the first optical element 914 and the second optical element 915 are different, thereby projecting the collimated light beam 919 to the outside space Different directions can scan a larger spatial range. In one embodiment, the controller 918 controls the

drivers

916 and 917 to drive the first optical element 914 and the second optical element 915, respectively. The rotation speeds of the first optical element 914 and the second optical element 915 may be determined according to the area and pattern expected to be scanned in practical applications.

Drives

916 and 917 may include motors or other drives.

In one embodiment, the second optical element 915 includes a pair of opposed non-parallel surfaces through which the light beam passes. In one embodiment, the second optical element 915 includes a prism whose thickness varies along at least one radial direction. In one embodiment, the second optical element 915 includes a wedge angle prism.

In one embodiment, the scanning module 902 further includes a third optical element (not shown) and a driver for driving the third optical element to move. Optionally, the third optical element includes a pair of opposed non-parallel surfaces through which the light beam passes. In one embodiment, the third optical element includes a prism whose thickness varies along at least one radial direction. In one embodiment, the third optical element includes a wedge angle prism. At least two of the first, second and third optical elements rotate at different rotational speeds and/or turns.

The rotation of each optical element in the scanning module 902 can project light into different directions, for example, the directions of the light 911 and 913, so as to scan the space around the distance measuring device 900. When the light 911 projected by the scanning module 902 hits the object 901 to be detected, a part of the light object 901 is reflected to the distance measuring device 900 in a direction opposite to the projected light 911. The returned light 912 reflected by the detected object 901 passes through the scanning module 902 and enters the collimating element 904.

The detector 905 and the emitter 903 are placed on the same side of the collimating element 904. The detector 905 is used to convert at least part of the returned light passing through the collimating element 904 into an electrical signal.

In one embodiment, each optical element is coated with an antireflection coating. Optionally, the thickness of the antireflection film is equal to or close to the wavelength of the light beam emitted by the emitter 103, which can increase the intensity of the transmitted light beam.

In one embodiment, a filter layer is plated on the surface of an element on the beam propagation path in the distance measuring device, or a filter is provided on the beam propagation path to transmit at least the wavelength band of the beam emitted by the transmitter, Reflect other bands to reduce the noise caused by ambient light to the receiver.

In some embodiments, the transmitter 903 may include a laser diode through which laser pulses in the order of nanoseconds are emitted. Further, the laser pulse receiving time may be determined, for example, by detecting the rising edge time and/or the falling edge time of the electrical signal pulse. In this way, the distance measuring device 900 can use the pulse receiving time information and the pulse sending time information to calculate the TOF, thereby determining the distance between the detected object 901 and the distance measuring device 900.

The distance and orientation detected by the distance measuring device 900 can be used for remote sensing, obstacle avoidance, mapping, modeling, navigation, and the like. In an embodiment, the distance measuring device of the embodiment of the present invention may be applied to a mobile platform, and the distance measuring device may be installed on the platform body of the mobile platform. A mobile platform with a distance-measuring device can measure the external environment, for example, measuring the distance between the mobile platform and obstacles for obstacle avoidance and other purposes, and performing two-dimensional or three-dimensional mapping of the external environment. In some embodiments, the mobile platform includes at least one of an unmanned aerial vehicle, a car, a remote control car, a robot, and a camera. When the distance measuring device is applied to an unmanned aerial vehicle, the platform body is the fuselage of the unmanned aerial vehicle. When the distance measuring device is applied to an automobile, the platform body is the body of the automobile. The car may be a self-driving car or a semi-automatic car, and no restriction is made here. When the distance measuring device is applied to a remote control car, the platform body is the body of the remote control car. When the distance measuring device is applied to a robot, the platform body is a robot. When the distance measuring device is applied to a camera, the platform body is the camera itself.

A signal amplification device provided according to an embodiment of the present invention includes:

Transmitting module, used to transmit optical pulse signal;

An amplification module for amplifying the electrical pulse signal;

Among them, the amplification gain of the optical conversion module differs at least part of the time between the moment of transmission of the optical pulse and the moment of reception of the reflected optical pulse signal, and/or the amplification gain of the amplification module is At least part of the time is different.

Optionally, the device further includes:

A control module for controlling the amplification gain of the optical conversion module and/or the amplification gain of the amplification module, so that the amplification gain of the optical conversion module and/or the amplification module at the first moment is greater than at the second moment Amplification gain of, wherein the first time and the second time are between the time of transmitting the optical pulse and the time of receiving the reflected optical pulse signal, and the first time is later than the second time.

Optionally, the control module is further configured to: control the amplification gain of the optical conversion module and/or the amplification gain of the amplification module at the time of transmitting the optical pulse and the time of receiving the reflected optical pulse signal Gradually increased.

Optionally, the control module is further configured to: control the amplification gain of the optical conversion module and/or the amplification gain of the amplification module at the time of transmitting the optical pulse and the time of receiving the reflected optical pulse signal Between linear growth.

Optionally, the control module is further configured to: control the amplification gain of the optical conversion module and/or the amplification gain of the amplification module at the time of transmitting the optical pulse and the time of receiving the reflected optical pulse signal Between the growth, and the rate of growth gradually accelerated.

Optionally, the device further includes an RC integration circuit, wherein the control module controls the voltage of the variable gain amplifier through the RC integration circuit, so that the voltage of the variable gain amplifier gradually increases.

Optionally, the control module is also used to:

From the moment of emission of the optical pulse signal, the amplification gain of the optical conversion module and/or the amplification module is controlled to increase from the initial value.

Optionally, the control module is further configured to: control the amplification gain of the optical conversion module and/or the amplification gain of the amplification module at the time of transmitting the optical pulse and the time of receiving the reflected optical pulse signal Stepwise growth.

Optionally, the amplification module includes a variable gain amplifier, and the control module controls the feedback resistance of the variable gain amplifier to change the amplification gain of the variable gain amplifier.

Optionally, the transmitting module is further configured to: transmit a sequence of optical pulses, wherein the interval between the transmission of two adjacent optical pulses is greater than at least 10 times the longest detection duration, wherein the longest detection duration is detectable The detection time of the smallest light pulse signal reflected by the object is the interval between the corresponding light pulse emission time.

Optionally, the control module is also used to:

According to an embodiment of the present invention, a distance measuring device is provided. The distance measuring device is configured to determine the object and the distance measuring device according to the transmitted optical pulse signal and the received optical pulse signal reflected by the object. The distance from the device; the distance measuring device includes the signal amplifying device described above.

Optionally, the distance measuring device further includes:

The present invention provides the above-mentioned signal amplification method, device and distance measuring device, by performing different amplification of the reflected optical pulse signal according to the difference in flight time of the reflected optical pulse signal to solve the problem If the information is lost or cannot be detected after amplification, ensuring that the reflected optical pulse signal is amplified at an appropriate magnification is conducive to improving the effectiveness and reliability of signal processing.

The technical terms used in the embodiments of the present invention are only used to describe specific embodiments and are not intended to limit the present invention. In this text, the singular forms "a", "the", and "said" are used to include plural forms unless the context clearly dictates otherwise. Further, the use of "including" and/or "comprising" in the specification refers to the existence of the described features, wholes, steps, operations, elements, and/or components, but does not exclude the presence or addition of one or more Other features, wholes, steps, operations, elements and/or components.

The corresponding structures, materials, actions, and equivalents of all devices or steps and functional elements (if any) in the appended claims are intended to include any structures, materials, or actions for performing the function in combination with other specifically required elements. The description of the present invention is given for the purpose of embodiments and description, but is not intended to be exhaustive or to limit the invention to the disclosed form. Various modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiments described in the present invention can better disclose the principle and practical application of the present invention, and enable those of ordinary skill in the art to understand the present invention.

The flow chart described in the present invention is only an embodiment, and there may be various modifications and changes to this illustration or the steps in the present invention without departing from the spirit of the present invention. For example, these steps can be performed in different orders, or certain steps can be added, deleted, or modified. Those of ordinary skill in the art may understand that all or part of the processes for implementing the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

A signal amplification method, characterized in that the method includes:

Emit light pulse signal;

Receiving the optical pulse signal reflected by the object through the optical conversion module, and converting the optical pulse signal into an electrical pulse signal;

Amplify the electrical pulse signal through an amplification module;

Among them, the amplification gain of the optical conversion module differs at least part of the time between the moment of transmission of the optical pulse and the moment of reception of the reflected optical pulse signal, and/or the amplification gain of the amplification module is At least part of the time is different.
The method of claim 1, further comprising:

Controlling the amplification gain of the optical conversion module and/or the amplification gain of the amplification module so that the amplification gain of the optical conversion module and/or the amplification module at the first moment is greater than the amplification gain at the second moment, wherein Both the first time and the second time are between the time of transmitting the light pulse and the time of receiving the reflected light pulse signal, and the first time is later than the second time.
The method of claim 2, the controlling the amplification gain of the light conversion module and/or the amplification gain of the amplification module comprises:

Controlling the amplification gain of the optical conversion module and/or the amplification gain of the amplification module to gradually increase between the transmission time of the optical pulse and the reception time of the reflected optical pulse signal.
The method of claim 3, the controlling the amplification gain of the light conversion module and/or the amplification gain of the amplification module comprising:

Controlling the amplification gain of the optical conversion module and/or the amplification gain of the amplification module to increase linearly between the transmission time of the optical pulse and the reception time of the reflected optical pulse signal.
The method of claim 3, the controlling the amplification gain of the light conversion module and/or the amplification gain of the amplification module comprising:

The amplification gain of the optical conversion module and/or the amplification gain of the amplification module is controlled to increase between the transmission time of the optical pulse and the reception time of the reflected optical pulse signal, and the growth rate is gradually accelerated.
The method of claim 3, wherein the amplification module includes a variable gain amplifier, and the controlling the amplification gain of the amplification module includes:

The voltage of the variable gain amplifier is controlled by an RC integration circuit so that the voltage of the variable gain amplifier gradually increases.
The method according to claim 3, wherein the controlling the amplification gain of the light conversion module and/or the amplification gain of the amplification module comprises:

From the moment of emission of the optical pulse signal, the amplification gain of the optical conversion module and/or the amplification module is controlled to increase from the initial value.
The method of claim 2, the controlling the amplification gain of the light conversion module and/or the amplification gain of the amplification module comprises:

Controlling the amplification gain of the optical conversion module and/or the amplification gain of the amplification module to increase stepwise between the transmission time of the optical pulse and the reception time of the reflected optical pulse signal.
The method according to any one of claims 1 to 5, 7 to 8, wherein the amplification module includes a variable gain amplifier or a programmable gain amplifier.
The method of claim 9, wherein the amplification module includes a variable gain amplifier, and the method further includes:

The feedback resistance of the variable gain amplifier is controlled to change the amplification gain of the variable gain amplifier.
The method according to any one of claims 1 to 10, wherein the method further comprises:

A sequence of emitted light pulses, in which the interval between two adjacent light pulses is at least 10 times longer than the longest detection duration, where the longest detection duration is the smallest detectable optical pulse signal reflected by an object The detection time is the interval between the corresponding light pulse emission time.
The method of claim 11, wherein the method further comprises:

Starting to control the amplification gain of the optical conversion module and/or the amplification gain of the amplification module to increase from the initial value at the emission timing of at least part of the optical pulses in the optical pulse sequence, respectively;

After the longest detection duration is reached from the emission time of the at least part of the optical pulses respectively, the amplification gain of the optical conversion module and/or the amplification gain of the amplification module are stopped from increasing.
The method according to any one of claims 1 to 10, wherein the method is applied to a distance measuring device, the method further comprising:

The distance between the object and the distance measuring device is determined according to the transmitted optical pulse signal and the received optical pulse signal reflected by the object.
The method of claim 13, wherein the method further comprises:

Emitting light pulse sequence;

The scanning module is used to change the exit direction of the optical pulse sequence, so that each optical pulse in the optical pulse sequence is sequentially emitted to different directions.
The method of claim 13, wherein the scanning module includes at least two rotating light refracting elements having non-parallel exit surfaces and entrance surfaces.
A signal amplifying device, characterized in that it includes:

Transmitting module, used to transmit optical pulse signal;

The light conversion module is used to receive the light pulse signal reflected by the object and convert the light pulse signal into an electrical pulse signal;

An amplification module for amplifying the electrical pulse signal;

Among them, the amplification gain of the optical conversion module differs at least part of the time between the moment of transmission of the optical pulse and the moment of reception of the reflected optical pulse signal, and/or the amplification gain of the amplification module is At least part of the time is different.
The apparatus of claim 16, wherein the apparatus further comprises:

A control module for controlling the amplification gain of the optical conversion module and/or the amplification gain of the amplification module, so that the amplification gain of the optical conversion module and/or the amplification module at the first moment is greater than at the second moment Amplification gain of, wherein the first time and the second time are between the time of transmitting the optical pulse and the time of receiving the reflected optical pulse signal, and the first time is later than the second time.
The device according to claim 17, wherein the control module is further configured to: control the amplification gain of the optical conversion module and/or the amplification gain of the amplification module at the time of emission of the optical pulse and The reflected optical pulse signal gradually increases between reception times.
The device according to claim 18, wherein the control module is further configured to: control the amplification gain of the optical conversion module and/or the amplification gain of the amplification module at the moment of emission of the optical pulse The reflected optical pulse signal increases linearly between the receiving moments.
The device according to claim 18, wherein the control module is further configured to: control the amplification gain of the optical conversion module and/or the amplification gain of the amplification module at the moment of emission of the optical pulse The reflected optical pulse signal grows between reception moments, and the growth rate gradually accelerates.
The apparatus of claim 18, wherein the apparatus further comprises an RC integration circuit, wherein the control module controls the voltage of the variable gain amplifier through the RC integration circuit so that the variable gain amplifier The voltage gradually increases.
The apparatus of claim 18, wherein the control module is further used to:

From the moment of emission of the optical pulse signal, the amplification gain of the optical conversion module and/or the amplification module is controlled to increase from the initial value.
The device according to claim 17, wherein the control module is further configured to: control the amplification gain of the optical conversion module and/or the amplification gain of the amplification module at the time of emission of the optical pulse and The reflected optical pulse signal increases stepwise between the reception moments.
The device according to any one of claims 16 to 20 and 22 to 23, wherein the amplification module includes a variable gain amplifier or a programmable gain amplifier.
The apparatus of claim 24, wherein the amplification module includes a variable gain amplifier, and the control module controls the feedback resistance of the variable gain amplifier to change the amplification gain of the variable gain amplifier.
The device according to any one of claims 16 to 25, wherein the transmitting module is further configured to: transmit a sequence of optical pulses, wherein the interval between the transmission of two adjacent optical pulses is greater than at least 10 Times, wherein the longest detection duration is the detection time of the smallest detectable light pulse signal reflected by the object and the interval between the corresponding light pulse emission time.
The device of claim 26, wherein the control module is further configured to:

Starting to control the amplification gain of the optical conversion module and/or the amplification gain of the amplification module to increase from the initial value at the emission timing of at least part of the optical pulses in the optical pulse sequence, respectively;

After the longest detection duration is reached from the emission time of the at least part of the optical pulses respectively, the amplification gain of the optical conversion module and/or the amplification gain of the amplification module are stopped from increasing.
A distance measuring device, characterized in that the distance measuring device is used to determine the distance between the object and the distance measuring device based on the emitted optical pulse signal and the received optical pulse signal reflected by the object The distance measuring device includes the signal amplifying device according to any one of claims 17 to 27.
The distance measuring device of claim 28, wherein the distance measuring device further comprises:

The scanning module is used to change the exit direction of the optical pulse sequence, so that each optical pulse in the optical pulse sequence is sequentially emitted to different directions.
The distance measuring device of claim 28, wherein the scanning module comprises: at least two rotating light refraction elements having non-parallel exit surfaces and entrance surfaces.