Laser radar ranging device and ranging method thereof

Abstract

The present application discloses a laser radar ranging device, characterized in that it includes a light source, a light source PD located inside the light source, a target to be measured, a receiving array, a conversion amplifier and a post-processing module; the light source emits detection light; the light source PD receives the detection light to generate a photocurrent, and sends the photocurrent of the light source PD to the conversion amplifier; the receiving array receives the reflected light of the target to be measured to generate a photocurrent and sends the photocurrent of the receiving array to the conversion amplifier; the output of the conversion amplifier is the input of the post-processing module, and the post-processing module obtains the distance of the target to be measured based on the received information. Such a design can solve the problem of long-distance ranging due to human eye safety restrictions, and can provide ranging resolution by increasing the number of receiving arrays to achieve high-precision ranging of long-distance targets to be measured.

Description

[0001] The present invention relates to the field of detection technology, and in particular to a laser radar ranging device and a ranging method thereof. Background Art

[0002] Distance detection, in particular, is an active detection system implemented using a laser source. The principle is to actively emit detection light through a light source, such as near-infrared detection light, the wavelength of which can be selected within the range of 800-1200nm. However, this is not limited to this. The use of near-infrared detection waves can also ensure safety when there are human objects in the field of view. Therefore, near-infrared active detection systems are becoming more and more commonly used in various scenarios, such as subsequent autonomous driving, smart door locks, security cameras, mobile phone three-dimensional cameras, etc.

[0003] Time-of-flight ("TOF") light detection and ranging ("LIDAR") is a technology used for long-range distance measurement. A TOF LIDAR sensor determines the distance between an instrument, including the sensor and an object, by measuring the time it takes for a laser pulse to travel between the instrument and the object.

[0004] Currently, the most widely used detection methods include indirect time-of-flight (ITOF) and direct time-of-flight (DTOF). Most indirect time-of-flight measurement methods use a phase shift method, which measures the phase difference between the transmitted and received waves. The horizontal coordinate of the transmitted and received waves is time t, and the vertical coordinate is light intensity. The flight time t can be obtained based on the phase difference between the two, and the distance to the detected object can be calculated according to D = c*t / 2. Direct time-of-flight measurement methods generally use a measurement system with picosecond resolution (mostly using SPAD + TDC) to directly obtain the time difference between the transmission and the corresponding receiving end trigger, which is the flight time t, and thus calculate the distance to the detected object. Due to the differences in the detection mechanisms of these two most widely used detection methods, the ITOF and DTOF detection systems have different requirements for the emitted pulsed light. Because the surface light source emitted by ITOF and DTOF has a large luminous area, the power per unit area is low. Increasing the transmission power is subject to eye safety restrictions. Therefore, both ITOF and DTOF detection methods suffer from the problem of short detection distance. How to perform long-distance ranging in distance detection is a technical problem that needs to be solved urgently. Summary of the Invention

[0005] The purpose of this application is to provide a laser radar ranging device and a ranging method thereof to solve the technical problem of long-distance ranging in response to the above-mentioned deficiencies in the prior art.

[0006] To achieve the above objectives, the technical solutions adopted in the embodiments of the present application are as follows:

[0007] In a first aspect, the present application provides a laser radar ranging device, characterized in that it includes a light source, a light source PD located inside the light source, a target to be measured, a receiving array, a conversion amplifier, and a post-processing module; the light source emits detection light; the light source PD receives the detection light to generate a photocurrent, and sends the photocurrent of the light source PD to the conversion amplifier; the receiving array receives the reflected light of the target to be measured to generate a photocurrent and sends the photocurrent of the receiving array to the conversion amplifier; the output of the conversion amplifier is the input of the post-processing module, and the post-processing module obtains the distance of the target to be measured based on the received information;

[0008] Optionally, the post-processing module includes a comparator and a PFGA;

[0009] Optionally, the light source PD and the receiving array are electrically connected to the conversion amplifier respectively;

[0010] Optionally, the light source PD is electrically connected to the light source and feeds back detection light parameter information to the light source for adjusting the parameters of the detection light to meet pre-set requirements;

[0011] Optionally, the post-processing module determines the emission time of the detection light according to the information of the light source PD, and the post-processing module obtains the distance of the target to be measured according to the time when the receiving array receives the reflected light of the target to be measured and the emission time of the detection light;

[0012] Optionally, a power supply module is further included, wherein the power supply module determines an output voltage value based on the bias voltage of the receiving array and the voltage allowable value of the conversion amplifier;

[0013] Optionally, the receiving array and the conversion amplifier are connected to a circuit board by gold wires, and three pins, namely, an anode, a cathode and a ground, are led out;

[0014] Optionally, the output module utilizes AC coupling, a resistor as a load, and uses a radio frequency terminal to lead out two voltages;

[0015] In a second aspect, the present application provides a laser radar ranging method, characterized in that the method includes the following steps: a light source radiates detection light; a light source PD receives the detection light and generates a photocurrent; a receiving array receives reflected light from a target to be measured and generates a photocurrent; the light source PD and the receiving array respectively send the photocurrent to a conversion amplifier; the conversion amplifier converts and amplifies the received information and sends it to a post-processing module; the post-processing module calculates the flight time and determines the distance of the target to be measured based on the received information;

[0016] Optionally, the time when the light source PD receives the detection light is the initial time when the light source emits the detection light.

[0017] The beneficial effects of this application are:

[0018] A laser radar ranging device, characterized in that it includes a light source, a light source PD located inside the light source, a target to be measured, a receiving array, a conversion amplifier and a post-processing module; the light source emits detection light; the light source PD receives the detection light to generate a photocurrent, and sends the photocurrent of the light source PD to the conversion amplifier; the receiving array receives the reflected light of the target to be measured to generate a photocurrent and sends the photocurrent of the receiving array to the conversion amplifier; the output of the conversion amplifier is the input of the post-processing module, and the post-processing module obtains the distance of the target to be measured based on the received information. Through such a design, the problem of long-distance ranging due to human eye safety restrictions can be solved, and the ranging resolution can be increased by increasing the number of receiving arrays to achieve high-precision ranging of long-distance targets to be measured. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 A schematic diagram of a ranging system provided in an embodiment of the present application;

[0021] Figure 2 A schematic diagram of a ranging circuit provided in an embodiment of the present application;

[0022] Figure 3 A flow chart of a distance measurement method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without making any creative efforts shall fall within the scope of protection of the present application.

[0025] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0026] Figure 1 This is a schematic diagram of a distance measurement system provided in an embodiment of the present application. Figure 1 The distance measurement system 10 shown includes a light source 101, a light source PD 102, a target to be measured 103, a receiving array 104, a conversion amplifier 105, and a post-processing module 106. The post-processing module may include a comparator and an FPGA. In one embodiment, the light source 101 includes a control unit for controlling parameters such as the pulse period, pulse width, and light source power emitted by the light source. These parameters can be pre-set. The light source 101 emits a probe light according to the pre-set parameters. The light source PD 102 is located within the light source 101. PD 102 receives the probe light and feeds back one or more of the received parameters, such as the light source power, pulse period, and pulse width, to the control module of the light source 101. The control module of the light source can adjust the emitted probe light based on the feedback information received from the light source PD 102 to meet pre-set requirements. In another embodiment, the light source PD can also determine the emission time of the light source based on the time of the received probe light. The light source can achieve high peak power and low pulse width laser output, for example, it can output a 1064nm laser. In other embodiments, the light source module further includes a temperature control module that utilizes a TEC (electrical rectifier) ​​for active temperature control, ensuring that the light source 101 stably outputs detection light in an environment ranging from -20°C to 50°C. The light source module utilizes a sealed structure to resist water vapor, dust, and oxidation, resulting in high reliability.

[0027] exist Figure 1In the embodiment described, the detection light is reflected by the target 103 and received by the receiving array PD 104. The receiving array 104 generates a photocurrent from the received reflected light. The receiving array 104 is electrically connected to the conversion amplifier 105, and the photocurrent is input to the amplifying converter. The conversion amplifier 105 is also electrically connected to the light source PD 102, and the light source PD 102 also inputs its current to the conversion amplifier 105. The conversion amplifier is used to convert the output current of a sensor (e.g., a photodiode) into a voltage signal and amplify it. In one embodiment, the conversion amplifier can be a simultaneous transimpedance amplifier (TIA). The time when the light source PD 102 receives the detection light is the light source emission time. The conversion amplifier is electrically connected to the post-processing module 106. The output of the conversion amplifier serves as the input of the post-processing module. The high-speed comparator in the post-processing module 106 is used to convert the analog signal into a digital signal. The FPGA obtains the time of flight based on the time of flight of the received reflected light and the time when the light source PD 102 receives the detection light, and calculates the distance of the target object based on the time of flight. In other embodiments, when the time of reflected light received in the receiving array PD is different, the time of reflected light received may be calculated by averaging.

[0028] Figure 2 This is a schematic diagram of a distance measurement circuit provided in an embodiment of the present application. Figure 2 The system shown includes a power supply module 201, a receiving array and conversion amplifier module 202, and an output amplifier module 203. The power supply module 201 supplies power to the conversion amplifier, voltage operational amplifier, and output buffer, respectively, with a supply voltage of 3.3V. The power supply module 201 adjusts the resistance value according to the receiving array bias and the allowable value of the conversion amplifier chip voltage to determine the output voltage value of the power supply. The output module 203 has two outputs, namely the output value of the photocurrent of the light source PD passing through the conversion amplifier 202, and the output value of the photocurrent of the receiving array passing through the conversion amplifier 202. The two outputs of the output module are further connected to the voltage operational amplifier and output buffer to compare and couple the output signals of the output module. During the coupling, the signals of the light source PD and the receiving array can be amplified and the useful signals can be extracted and transmitted to the post-processing module for calculating the flight time, and the distance of the target to be measured can be further obtained based on the flight time.

[0029] The receiving array has an input current range of 0.5uA to 3mA, a bandwidth of 9.5GHz, a rise time of approximately 37ps, and a reverse bias voltage range of -3 to 0V. When testing high currents, direct detection is performed using a resistor loop. The receiving array and conversion amplifier are connected to a circuit board using gold wires, with the anode, cathode, and ground pins exposed. Increasing the number of pixels in the receiving array increases ranging resolution.

[0030] The output module 203 utilizes AC coupling, uses a resistor as a load, and uses a radio frequency terminal to output two voltages.

[0031] Figure 3 This is a flow chart of a laser radar ranging method provided in an embodiment of the present application. Figure 3 The distance measurement method shown includes the following steps:

[0032] S301: The light source emits a detection light, wherein a portion of the detection light is received by the light source PD and a portion is sent to the target to be measured;

[0033] S302: The light source PD receives the detection light and generates a photocurrent;

[0034] S303: The light source PD sends the photocurrent to the conversion amplifier;

[0035] S304: The target to be measured reflects the detection light, and the receiving array receives the emission light and generates a photocurrent;

[0036] S305: The receiving array sends the photocurrent to the conversion amplifier;

[0037] S306: The conversion amplifier converts and amplifies the received photocurrent into a voltage signal and outputs the voltage signal to the post-processing module;

[0038] S307: The post-processing module determines the flight time based on the received information and further obtains the distance of the target to be measured. The time when the light source PD receives the detection light is the initial time when the light source emits the detection light.

[0039] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0040] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application. It should be noted that similar numbers and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. The above description is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A laser radar ranging device, characterized in that: The system comprises a light source, a light source PD located inside the light source, a target to be measured, a receiving array, a conversion amplifier, and a post-processing module; the light source emits detection light; the light source PD receives the detection light to generate a photocurrent, and sends the photocurrent of the light source PD to the conversion amplifier; the receiving array receives the reflected light of the target to be measured to generate a photocurrent, and sends the photocurrent of the receiving array to the conversion amplifier; the output of the conversion amplifier is the input of the post-processing module, and the post-processing module obtains the distance of the target to be measured based on the received information; The laser radar device further includes an output module, wherein the two outputs of the output module are respectively an output value of the photocurrent of the light source PD passing through the conversion amplifier and an output value of the photocurrent of the receiving array passing through the conversion amplifier; The two outputs of the output module are connected to the voltage operational amplifier and the output buffer, and the two outputs of the output module are compared and coupled. The signals of the light source PD and the receiving array are amplified and extracted to the post-processing module for calculating the flight time, and the distance of the target to be measured is obtained according to the flight time.

2. The laser radar ranging device according to claim 1, wherein The post-processing module includes a comparator and a PFGA.

3. The laser radar ranging device according to claim 1, wherein: The light source PD and the receiving array are electrically connected to the conversion amplifier respectively.

4. The laser radar ranging device according to claim 1, wherein: The light source PD is electrically connected to the light source and feeds back detection light parameter information to the light source for adjusting the parameters of the detection light to meet preset requirements.

5. The laser radar ranging device according to claim 1, wherein: The post-processing module determines the emission time of the detection light according to the information of the light source PD, and obtains the distance of the target according to the time when the receiving array receives the reflected light of the target and the emission time of the detection light.

6. The laser radar ranging device according to claim 1, wherein: It also includes a power supply module, which determines the output voltage value according to the bias voltage of the receiving array and the voltage allowable value of the conversion amplifier.

7. The laser radar ranging device according to claim 1, wherein: The receiving array and the conversion amplifier are connected to a circuit board in a gold wire manner, and three pins, an anode pin, a cathode pin and a ground pin are led out.

8. A laser radar ranging method, characterized in that: The method comprises the following steps: a light source radiates detection light; a light source PD receives the detection light and generates a photocurrent; a receiving array receives reflected light from a target to be measured and generates a photocurrent; the light source PD and the receiving array respectively send the photocurrent to a conversion amplifier; the conversion amplifier converts and amplifies the received information and sends it to a post-processing module; The output value of the photocurrent of the PD through the conversion amplifier and the output value of the photocurrent of the receiving array through the conversion amplifier are compared and coupled, the signals of the light source PD and the receiving array are amplified and the signals are extracted to the post-processing module for calculating the flight time, and the distance of the target to be measured is obtained according to the flight time.

9. The laser radar ranging method according to claim 8, wherein: The time when the light source PD receives the detection light is the initial time when the light source emits the detection light.

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