CN114556151A

CN114556151A - Distance measuring device, distance measuring method and movable platform

Info

Publication number: CN114556151A
Application number: CN202080070692.0A
Authority: CN
Inventors: 马亮亮; 王栗
Original assignee: SZ DJI Technology Co Ltd
Current assignee: SZ DJI Technology Co Ltd
Priority date: 2020-12-16
Filing date: 2020-12-16
Publication date: 2022-05-27
Also published as: WO2022126429A1

Abstract

A ranging apparatus, a ranging method and a movable platform, the ranging apparatus (100) comprising: a light emitter (110), an optical system, a first receiving circuit (120a), a second receiving circuit (120b), and a processing module (130), the light emitter (110) for sequentially emitting a light pulse signal; at least part of echo signals of the optical pulse signals reflected by the object are converged by the optical system and then received by the first receiving circuit (120 a); the second receiving circuit (120b) and the first receiving circuit (120a) are simultaneously started, and optical signals received by the first receiving circuit (120a) and the second receiving circuit (120b) in the same time period are respectively a first optical signal and a second optical signal; the processing module (130) is used for judging whether the first optical signal is noise according to the strength of the first optical signal and the second optical signal. The scheme can improve the anti-interference performance of the distance measuring device.

Description

Distance measuring device, distance measuring method and movable platform

Technical Field

The present invention relates generally to the field of ranging technologies, and more particularly to a ranging device, a ranging method, and a movable platform.

Background

The laser ranging device detects parameters such as distance, direction and shape of a measured object by emitting laser pulse signals, and is used as an advanced sensing device capable of sensing three-dimensional information of an environment, and the laser ranging device is widely applied to the fields of various intelligent robots, auxiliary driving, automatic driving and the like in recent years.

The laser ranging device mainly emits light pulse signals to a measured object, and then compares the received signals reflected from the measured object with the emitted signals to obtain parameters such as distance, direction, shape and the like of the measured object. However, in addition to receiving the echo signal returned by the measured object, the laser distance measuring device may also receive noise, and the existence of the noise will affect the determination of the measured object by the distance measuring device, so how to determine whether the signal received by the distance measuring device is noise is a problem to be solved.

Disclosure of Invention

A series of concepts in a simplified form are introduced in the summary section, which is described in further detail in the detailed description section. This summary of the invention is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

In view of the deficiencies of the prior art, a first aspect of the embodiments of the present invention provides a distance measuring device, which includes a light emitter, an optical system, a first receiving circuit, a second receiving circuit, and a processing module, wherein:

the light emitter is used for sequentially emitting light pulse signals;

at least part of echo signals of the optical pulse signals reflected by the object are collected by the optical system and then received by the first receiving circuit;

the second receiving circuit and the first receiving circuit are simultaneously started, and optical signals received by the first receiving circuit and the second receiving circuit in the same time period are respectively a first optical signal and a second optical signal;

the processing module is used for judging whether the first optical signal is noise or not according to the intensity of the first optical signal and the second optical signal.

A second aspect of the embodiments of the present invention provides a distance measurement method, where the distance measurement method includes:

turning on a light emitter to emit a light pulse signal;

simultaneously starting a first receiving circuit and a second receiving circuit, wherein the first receiving circuit receives at least part of echo signals of the optical pulse signals after being converged by an optical system;

judging whether the first optical signal is noise or not according to the strength of a first optical signal and a second optical signal, wherein the first optical signal and the second optical signal are respectively optical signals received by the first receiving circuit and the second receiving circuit in the same time period.

A third aspect of an embodiment of the present invention provides a movable platform, including:

a movable platform body; and the distance measuring device provided by the first aspect of the embodiment of the present invention is mounted on the movable platform body.

According to the distance measuring device, the distance measuring method and the movable platform provided by the embodiment of the invention, at least part of echo signals reflected by an object from optical pulse signals emitted by the light emitter are converged by the optical system and then received by the first receiving circuit, the second receiving circuit and the first receiving circuit are simultaneously started, the optical signals received by the first receiving circuit and the second receiving circuit in the same time period are respectively the first optical signal and the second optical signal, and whether the first optical signal is noise or not is judged according to the strength of the first optical signal and the second optical signal, so that the anti-interference performance of the distance measuring device is improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required to be used in the description of the embodiments of the present invention will be briefly introduced below in order to more clearly illustrate the technical solutions in the embodiments of the present invention, and it is obvious that the drawings in the description below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings may be obtained according to the drawings without inventive labor.

Fig. 1 is a block diagram illustrating a ranging apparatus according to an embodiment of the present invention;

FIG. 2 illustrates a schematic spatial layout of a distance measuring device according to an embodiment of the present invention;

FIG. 3 illustrates an optical path diagram of a ranging device according to one embodiment of the present invention;

FIG. 4 shows a circuit diagram of a receiving circuit of a ranging apparatus according to one embodiment of the present invention;

fig. 5 shows a circuit diagram of a receiving circuit of a ranging apparatus according to another embodiment of the present invention;

fig. 6 shows a schematic flow diagram of a ranging method according to an embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, exemplary embodiments according to the present invention will be described in detail below with reference to the accompanying drawings. It is to be understood that the described embodiments are merely a subset of embodiments of the invention and not all embodiments of the invention, with the understanding that the invention is not limited to the example embodiments described herein. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the invention described herein without inventive step, shall fall within the scope of protection of the invention.

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the invention.

It is to be understood that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of the associated listed items.

In order to provide a thorough understanding of the present invention, a detailed structure will be set forth in the following description in order to explain the present invention. Alternative embodiments of the invention are described in detail below, however, the invention may be practiced in other embodiments that depart from these specific details.

The following describes the distance measuring device, the distance measuring method, and the movable platform in detail with reference to the accompanying drawings. The features of the following examples and embodiments may be combined with each other without conflict.

First, a structure of a distance measuring device according to an embodiment of the present invention will be described in detail with reference to fig. 1. The distance measuring device of the embodiment of the invention can be electronic equipment such as a laser radar, laser distance measuring equipment and the like. In one embodiment, the ranging device is used to sense external environmental information, such as distance information, orientation information, reflected intensity information, velocity information, etc. of environmental targets.

In one implementation, the ranging device may detect the distance of the probe to the ranging device by measuring the Time of Flight (TOF), which is the Time-of-Flight Time, of light traveling between the ranging device and the probe. Alternatively, the distance measuring device may detect the distance from the probe to the distance measuring device by other techniques, such as a distance measuring method based on phase shift (phase shift) measurement or a distance measuring method based on frequency shift (frequency shift) measurement, which is not limited herein.

As shown in fig. 1, a distance measuring apparatus 100 according to an embodiment of the present invention includes a light emitter 110, an optical system (not shown), a receiving circuit 120, and a processing module 130.

Wherein the optical transmitter 110 is used to sequentially transmit optical pulse signals. The number of the light emitters 110 may be one or more. The direction of the light pulse signals emitted by different light emitters 110 is the same or different, preferably, the direction of the light pulse signals emitted by different light emitters 110 is different, and the light emitters are packaged together or separately. Alternatively, the light emitter 110 may be a laser. The receiving circuit 120 is used for receiving optical signals.

The receiving circuit 120 at least includes a first receiving circuit 120a and a second receiving circuit 120b, at least a part of echo signals reflected by the object from the optical pulse signals emitted by the optical transmitter 110 are converged by the optical system and then received by the first receiving circuit 120a, the second receiving circuit 120b and the first receiving circuit 120a are simultaneously turned on, and optical signals received by the first receiving circuit 120a and the second receiving circuit 120b in the same time period are respectively a first optical signal and a second optical signal. That is, in the time range in which the first receiving circuit 120a is turned on to receive at least a part of the echo signals after the light pulse signals transmitted by the corresponding light emitter are converged by the optical system, the second receiving circuit 120b is also turned on at the same time, the first receiving circuit 120a receives the first optical signal, and the second receiving circuit 120b receives the second optical signal at the same time. The processing module 130 is configured to determine whether the first optical signal is noise according to the intensities of the first optical signal and the second optical signal, so as to improve the anti-interference performance of the laser ranging device.

For convenience of description, in the embodiment of the present invention, a light emitter which is turned on in a current time range is referred to as a first light emitter 110a, at least a part of echo signals reflected by an object, which are transmitted by the first light emitter 110a, are collected by an optical system and then received by a first receiving circuit 120a, a receiving circuit which is turned on in the same time range as the first receiving circuit 120a is referred to as a second receiving circuit 120b, a light emitter corresponding to the second receiving circuit 120b is referred to as a second light emitter 110b, and the second light emitter 110b is not turned on in the current time range, so that the light emitter is represented by a dotted line in fig. 1.

When the receiving circuit is turned on to receive the optical signal, the received optical signal may include an echo signal of the optical pulse signal transmitted by the optical transmitter and reflected by the object to be measured, but may also include noise. The noise may be a floodlight signal, for example, light incident on the photoelectric converter after multiple reflections of stray light from other directions occur inside the distance measuring device, and the intensity of such noise is weak. The noise may also be light emitted by other light sources in the working scene of the distance measuring device and being the same as or parallel to the receiving light path of the distance measuring device, and the intensity of the noise is very strong, even far stronger than the echo signal returned by the measured object.

In order to distinguish between noise and echo signals, the processing module 130 compares the strength of the first optical signal received by the first receiving circuit 120a and the strength of the second optical signal received by the second receiving circuit 120b, and determines whether the first optical signal is noise according to the comparison result.

Referring to fig. 3, the light pulse signal emitted by the first phototransmitter irradiates the field of view (FOV) corresponding to the first phototransmitter, and the echo signal 304 reflected by the object to be measured in the field of view is converged onto the first photoelectric converter 301 in the first receiving circuit through the optical system 303, where the first receiving circuit is in an on state, and the first photoelectric converter 301 can receive the optical signal, where the optical signal received by the first photoelectric converter 301 includes at least part of the echo signal. When the first receiving circuit is turned on, the second receiving circuit is also turned on, and since the second receiving circuit does not correspond to the currently turned on first optical transmitter, the optical system 303 does not converge the echo signal onto the second optical-to-electrical converter 302 in the second receiving circuit, so that the second optical-to-electrical converter 302 cannot receive the echo signal, and can only receive noise, for example, an optical signal reflected by stray light 305 in other directions inside the distance measuring device, where the signal is a floodlight signal with a weak intensity. Therefore, if the optical signal received by the first receiving circuit includes an echo signal and the optical signal received by the second receiving circuit is a floodlight signal, the intensity of the second optical signal received by the second receiving circuit will be much lower than the intensity of the first optical signal received by the first receiving circuit.

On the contrary, if there is no echo signal in the current time range, the first receiving circuit and the second receiving circuit both receive floodlight signals, and the reflected stray light does not have strong directivity, and the difference of light intensity distribution in each direction is relatively small, so that the intensity of the first optical signal received by the first receiving circuit is similar to that of the second optical signal received by the second receiving circuit.

Therefore, in one embodiment, if the ratio of the intensities of the first optical signal and the second optical signal is less than or equal to the first threshold, the processing module 130 determines that the first optical signal is noise. As an example, the first threshold has a value range of (0, 3), and the intensity ratio of the first optical signal to the second optical signal can be considered to be similar in the value range.

Further, as described above, when the echo signal is included in the first optical signal, the intensity of the first optical signal is much larger than that of the second optical signal; meanwhile, due to the limitation of the power of the optical transmitter and other factors, the intensity of the first optical signal is not unlimited greater than the intensity of the second optical signal, and therefore, if the intensity ratio of the first optical signal to the second optical signal is between the second threshold and the third threshold, the processing module 130 determines that the first optical signal is not noise, where the second threshold is smaller than the third threshold. It will be appreciated that the second threshold is greater than or equal to the first threshold described above. The specific values of the second threshold and the third threshold may be set according to the parameters of the ranging device, the application scenario of the ranging device, and other factors.

By adopting the above determination method, it can be effectively determined whether the first optical signal received by the first receiving circuit 120a is noise. When the first optical signal is not determined to be noise, the processing module 130 may perform ranging according to the first optical signal; when the first optical signal is noise, the processing module 130 may not use the first optical signal to measure the distance, and optionally, the processing module 130 may filter the first optical signal, so that noise caused by stray light may be effectively removed, and generation of noise points in the point cloud may be reduced.

It is understood that the second optical signal is used for comparison purposes only, and the processing module 130 does not perform ranging according to the second optical signal.

In another case, the noise incident on the first receiving circuit is a light ray emitted by another light source (e.g., a lidar of another vehicle in a road scene) and parallel to the receiving optical path, and the intensity of the first optical signal received by the first receiving circuit is much greater than that of the second optical signal received by the second receiving circuit. Therefore, in one embodiment, if the ratio of the first optical signal to the second optical signal is greater than or equal to a fourth threshold, the processing module 130 determines that the first optical signal is noise. Wherein the fourth threshold is greater than the third threshold.

The fourth threshold may be set according to factors such as parameters of the ranging apparatus and an application scenario of the ranging apparatus. As an example, the fourth threshold may be determined according to the intensity of the light pulse signal emitted by each light emitter 110. Specifically, the intensity ranges P1-P2 of the floodlight signal received by the receiving circuit 120 in the absence of the echo signal can be predetermined, and the maximum intensity of the light pulse signal emitted by the light emitter 110 is Pmax, so when the ratio of the first optical signal to the second optical signal is greater than or equal to Pmax/P1, the first optical signal can be considered to include the direct light from the other light sources parallel to the currently received light path, and thus the first optical signal can be determined to be noise at this time.

By adopting the above judging mode, whether the first optical signal includes light rays from other light sources can be effectively judged, so that the influence brought by other light sources can be inhibited.

In some embodiments, the receiving circuit 120 may include more than two second receiving circuits 120b, and the processing module 130 combines the second optical signals of the more than two second receiving circuits 120b to compare with the first optical signal, so as to improve the accuracy of the determination result. For example, the processing module 130 determines that the first optical signal is noise only when the comparison result of the second optical signal and the first optical signal received by the at least two receiving circuits satisfies the condition for determining that the first optical signal is noise as described above. Alternatively, the processing module 130 determines that the first optical signal is not noise only when the comparison result of the second optical signal and the first optical signal received by the at least two receiving circuits satisfies the condition for determining that the first optical signal is not noise as described above.

In some embodiments, the first receiving circuit 120a includes a first optical-to-electrical converter for receiving an optical signal and converting the optical signal into an electrical signal; the distance measuring device 100 further includes a first sampling circuit, the first sampling circuit is connected to the first receiving circuit 120a and the processing module 130, and is configured to sample the electrical signal output by the first receiving circuit 120a to obtain a sampling signal, and send the sampling signal to the processing module 130, and the processing module 130 determines the intensity of the optical signal according to the sampling signal.

In some embodiments, the second receiving circuit 120b includes a second optical-to-electrical converter for receiving an optical signal and converting the optical signal into an electrical signal; the distance measuring device 100 further includes a second sampling circuit, the second sampling circuit is connected to the second receiving circuit and the processing module, and is configured to sample the electrical signal output by the second receiving circuit to obtain a sampling signal, and send the sampling signal to the processing module 130, and the processing module 130 determines the intensity of the optical signal according to the sampling signal. Optionally, the first and second photoelectric converters comprise APDs (avalanche photodiodes), PIN photodiodes or other photosensitive devices. Each photoelectric converter may include one or more photosensitive devices, for example, each photoelectric converter may include one or more APDs in an APD array. After the light beam emitted from the light emitter 110 is reflected by the object to be measured, the echoes returned by the object to be measured in different field areas are respectively converged by the optical system onto the photoelectric converters located at different positions, and when the photosensitive surface of the photoelectric converter is irradiated by the detection light, the photo-generated carriers drift under the action of the electric field, and generate photocurrent in the external circuit.

Illustratively, ranging device 100 includes at least three photoelectric converters. Illustratively, at least a portion of the at least three photoelectric converters is disposed at equal intervals. For example, a plurality of photoelectric converters may be arranged in equally spaced linear or planar arrays, each of which may correspond to a field of view of the same size. Illustratively, among the at least three photoelectric converters, at least a part of the photoelectric converters are arranged at unequal intervals. For example, the photoelectric converters corresponding to a partial field of view region (e.g., a central field of view region) may be arranged relatively densely to acquire more information, while the photoelectric converters corresponding to other partial field of view regions (e.g., an edge field of view region) may be arranged relatively sparsely.

The receiving circuit 120 may further include a current-voltage converting circuit, which is connected to the photoelectric converter and the sampling circuit, and is configured to convert a current signal output by the photoelectric converter into a voltage signal and send the voltage signal to the sampling circuit. The current-to-voltage conversion circuit may include a transimpedance amplifier (TIA) that converts a current signal to a voltage signal and may provide gain. The current-voltage conversion circuit can also adopt a capacitor or other types of capacitor-voltage conversion devices. The current-to-voltage conversion circuit may also be considered as a one-stage amplifier.

In some embodiments, the first receiving circuit 120a further includes a current-voltage converting circuit, which is connected to the first photoelectric converter and the first sampling circuit, and is configured to convert a current signal output by the first photoelectric converter into a voltage signal and send the voltage signal to the first sampling circuit.

In some embodiments, the second receiving circuit 120b further includes a current-voltage converting circuit, which is connected to the second photoelectric converter and the second sampling circuit, and is configured to convert a current signal output by the second photoelectric converter into a voltage signal and send the voltage signal to the second sampling circuit.

In some embodiments, the transimpedance amplifier may also be used to implement a circuit gating function, i.e., to turn on a receive circuit including the transimpedance amplifier or to turn off a receive circuit including the transimpedance amplifier. In other embodiments, the gating of the receiving circuits may also be implemented by switches, i.e., the ranging apparatus 100 further includes a switch connected to each receiving circuit 120, the switch being used to turn on the receiving circuit connected thereto or turn off the receiving circuit connected thereto.

In some embodiments, the first sampling circuit and the second sampling circuit may have the same or different structures, and are used for sampling the electrical signal. The sampling signals output by the first sampling circuit and the second sampling circuit are sent to the processing module, and the processing module can determine the size of the optical signal according to the sampling signals so as to determine whether distance measurement is carried out according to the first optical signal. As an example, the first sampling circuit and the second sampling circuit include at least two implementations as follows:

as one implementation, the sampling circuit includes a comparator (e.g., an analog Comparator (COMP) for converting the electrical signal into a digital signal) and a Time-to-Data Converter (TDC), the electrical signal amplified by the first-stage or second-stage amplifying circuit passes through the comparator and then a Time measuring circuit, and the Time measuring circuit measures a Time difference between the emission and the reception of the laser pulse sequence.

The TDC may be an independent TDC chip, or a TDC Circuit that implements time measurement based on an internal delay chain of a Field-Programmable Gate Array (FPGA) or an Application-Specific Integrated Circuit (ASIC) or a Complex Programmable Logic Device (CPLD), or a Circuit structure that implements time measurement by using a high-frequency clock or a counting method.

Illustratively, the first input end of the comparator is used for receiving the electric signal input from the amplifying circuit, the second input end is used for receiving a preset threshold value, and the electric signal input to the comparator is compared with the preset threshold value. The output signal of the comparator enters the TDC, which measures the time information of the edge of the output signal of the comparator, the measured time being referenced to the laser emission signal, i.e. the time difference between the emission and the reception of the laser signal can be measured.

As another implementation, the sampling circuit includes an Analog-to-Digital Converter (ADC). The analog signal input to the sampling circuit may output a digital signal to the arithmetic circuit after analog-to-digital conversion by the ADC. Similarly, the ADC may be a separate ADC chip or an ADC circuit implemented by a Programmable device such as a Field-Programmable Gate Array (FPGA).

In some embodiments, each receiving circuit (e.g., the first receiving circuit or the second receiving circuit) may also include at least one signal Amplifier (AMP), which may be connected after the transimpedance amplifier for further providing gain to the electrical signal from the transimpedance amplifier to amplify the weak signal output by the transimpedance amplifier to a voltage recognizable by the comparator.

Illustratively, the receiving circuit includes, in addition to the first receiving circuit and the second receiving circuit which are turned on in the present time range, at least one third receiving circuit which is turned off in the present time range, each third receiving circuit corresponding to one third light emitter. The third receiving circuit may include a third photoelectric converter.

In some embodiments, each receiving circuit is connected with one sampling circuit, that is, the first receiving circuit is connected with the first sampling circuit, each second receiving circuit is connected with each second sampling circuit respectively, each third receiving circuit is connected with each third sampling circuit respectively, and each receiving circuit and each sampling circuit operate independently, so that crosstalk is small. Fig. 4 shows an exemplary circuit configuration employing this scheme. In the circuit configuration shown in fig. 4, the first receiving circuit 410, the second receiving circuit 420, and the at least two third receiving circuits 430 each include a photoreceiver, a transimpedance amplifier (TIA), and a secondary Amplifier (AMP), and each secondary amplifier is connected to one sampling circuit.

In other embodiments, when the first receiving circuit and the second receiving circuit are simultaneously turned on, and the rest of the third receiving circuits are turned off, the sampling circuit can be multiplexed among part of the receiving circuits which are not turned on in the same time range, so that the hardware cost and the power consumption are reduced. For example, the first receiving circuit and the at least one third receiving circuit may multiplex the same first sampling circuit, and the second receiving circuit and the remaining at least one third receiving circuit may multiplex the same second sampling circuit. Because the first receiving circuit and the second receiving circuit are started at the same time, the first receiving circuit and the second receiving circuit do not multiplex the same sampling circuit with the same third receiving circuit.

In addition, if the receiving circuit includes two or more second receiving circuits, the sampling circuit is not multiplexed between the two or more second receiving circuits because the two or more second receiving circuits are turned on in the same time range.

Specifically, as shown in fig. 5, in the circuit configuration shown in fig. 5, the first receiving circuit 510 and the first third receiving circuit 530 multiplex the same sampling circuit, and the second receiving circuit 520 and the second third receiving circuit 540 multiplex the same sampling circuit. In addition, since the transimpedance amplifier (TIA) may perform the function of circuit gating, each receiving circuit may include a transimpedance amplifier, thereby performing independent gating of each receiving circuit. Two receiving circuits multiplexing the same sampling circuit may also simultaneously multiplex a two-stage Amplifier (AMP) to further save cost.

Although the same sampling circuit is multiplexed by every two receiving circuits in the circuit structure shown in fig. 5, in other examples, because a plurality of third receiving circuits that are not turned on in the current time range exist in the same time range, three or more receiving circuits may multiplex the same sampling circuit, that is, the first receiving circuit may multiplex the same sampling circuit with two or more third receiving circuits, and the second receiving circuit may multiplex the same sampling circuit with the other two or more third receiving circuits, only it is required to ensure that the first receiving circuit and the second receiving circuit that are turned on simultaneously in the same time range do not multiplex the same sampling circuit.

It should be noted that, in the embodiment of the present invention, multiplexing situations may be combined and changed at will, and whether multiplexing is performed or not and which circuits are multiplexed may be determined according to actual needs, for example, when multiplexing exists in part of receiving circuits, and when multiplexing does not exist in part of receiving circuits, any combination of the above situations falls within the protection scope of the present invention.

As described above, in the embodiment of the present invention, whether the first optical signal is noise is determined with reference to the intensity of the second optical signal, and the first optical signal is considered to be noise when the intensities of the first optical signal and the second optical signal are close. However, when the distance between the first optical signal receiving optoelectronic transducer and the second optical signal receiving optoelectronic transducer is too far, the first optical signal and the second optical signal are both floodlight but have large intensity difference, which may cause erroneous determination. Thus, in one embodiment, the first photoelectric converter may be disposed adjacent to the second photoelectric converter. That is, in each time range, two adjacent photoelectric converters are simultaneously turned on to receive the optical signal, so that when no echo signal is incident, the first receiving circuit and the second receiving circuit will receive the floodlight signal with approximate intensity, thereby avoiding the occurrence of misjudgment.

Further, in addition to the photoelectric converter, the transimpedance amplifiers connected after the photoelectric converter in the first receiving circuit and the second receiving circuit may also be disposed adjacently, thereby further improving the accuracy of the determination.

In some embodiments, the distance between the first and second photoelectric converters may be set within a certain range, thereby ensuring that the first and second photoelectric converters can receive similar floodlight signals. As an example, the distance between the first photoelectric converter and the second photoelectric converter is between 0.3 mm and 2 mm, for example, the distance between the first photoelectric converter and the second photoelectric converter may be set to about 0.5 mm, and the intensity of the floodlight signal received by the first photoelectric converter and the second photoelectric converter within the distance is similar. When the distance between the first photoelectric converter and the second photoelectric converter is within the above-described certain range, the first photoelectric converter and the second photoelectric converter may be disposed adjacently or may be disposed at an interval.

In one embodiment, the first photoelectric converter of the first receiving circuit and the third photoelectric converter of the third receiving circuit which multiplex the same first sampling circuit are arranged at intervals, and the second photoelectric converter of the second receiving circuit and the third photoelectric converter of the third receiving circuit which multiplex the same second sampling circuit are arranged at intervals, so that crosstalk between circuits is reduced. For example, referring to fig. 5, the first receiving circuit 510 and the first third receiving circuit 530 multiplex the same sampling circuit, and the first photoelectric converter of the first receiving circuit 510 and the third photoelectric converter of the first third receiving circuit 530 are disposed at an interval; the second receiving circuit 520 and the second third receiving circuit 540 multiplex the same sampling circuit, and the second photoelectric converter of the second receiving circuit 520 and the third photoelectric converter of the second third receiving circuit 540 are arranged at an interval.

Further, a second photoelectric converter of the second receiving circuit is provided between the first photoelectric converter of the first receiving circuit and the third photoelectric converter of the third receiving circuit that share the same first sampling circuit, that is, the first photoelectric converter and the third photoelectric converter are spaced apart by the second photoelectric converter. With continued reference to fig. 5, a second photoelectric converter of the second receiving circuit 520 is disposed between the first photoelectric converter of the first receiving circuit 510 and the third photoelectric converter of the first third receiving circuit 530.

The distance measuring apparatus 100 further includes an optical system including an optical path changing element for changing an optical path of an optical signal incident thereon so that the optical signal is received by the photoelectric converter.

As an example, the optical path changing element may include a lens group disposed in front of the photoelectric converter. The lens group may be designed to be composed of a single lens or multiple lenses, the lens surface type is a spherical surface, an aspherical surface or a combination of a spherical surface and an aspherical surface, and the lens material of the lens may include glass, plastic or a combination of glass and plastic, which is not limited in this embodiment of the present invention. Illustratively, the lens set structure may be sufficiently athermalized to compensate for the effects of temperature drift on imaging.

In some embodiments, the light pulse signal emitted by the light emitter covers a certain field of view, and the return echo signal from the field of view is focused by the optical path changing element onto the photoelectric converter corresponding to the light emitter. In the embodiment of the present invention, since the first receiving circuit and the second receiving circuit are simultaneously turned on, in order to avoid the difficulty in comparison caused by the second receiving circuit and the first receiving circuit receiving the echo signal at the same time, the optical path changing element may be preferably designed to converge the echo signal within a range smaller than the size of the photoelectric converter, so as to avoid crosstalk caused when two adjacent photoelectric converters are simultaneously turned on.

As an example, the first receiving circuit comprises a first photoelectric converter, the second receiving circuit comprises a second photoelectric converter, and the ratio of the distance between the first photoelectric converter and the second photoelectric converter to the focal length of the optical path changing element is not more than 1/6, so that the first photoelectric converter and the second photoelectric converter can receive similar floodlight signals, and the optical path changing element can be ensured to converge echo signals on the first photoelectric converter.

In some embodiments, the optical system includes an optical path changing element for changing an optical path of an optical signal incident thereon so that the optical signal is received by the first receiving circuit, wherein a focal length of the optical path changing element is between 28 mm and 32 mm, and the optical path changing element having the focal length range can preferably achieve the above-described function of the optical path changing element in the embodiments of the present invention. Illustratively, the focal length of the optical path changing element may be set to about 30 mm.

If the processing module 130 determines that the first optical signal is not noise, the distance information of the object to be measured can be calculated according to the time difference between the transmission and the reception of the first optical signal and the laser transmission rate. Thereafter, the processing module 130 may generate an image or the like based on the calculated information, which is not limited herein. The distance and orientation detected by ranging device 100 may be used for remote sensing, obstacle avoidance, mapping, modeling, navigation, and the like.

In some implementations, in addition to the circuit shown in fig. 1, the distance measuring apparatus 100 may further include a scanning module, configured to change a propagation direction of at least one light pulse sequence (e.g., a laser pulse sequence) emitted by the emitting circuit to emit light, so as to scan the field of view. Illustratively, the scan area of the scan module within the field of view of the ranging device increases over time.

The module comprising the light emitter 110, the receiving circuit 120 and the processing module 130 may be referred to as a ranging module, which may be independent of other modules, such as a scanning module, among others.

The distance measuring device can adopt a coaxial light path, namely the light beam emitted by the distance measuring device and the reflected light beam share at least part of the light path in the distance measuring device. For example, at least one path of laser pulse sequence emitted by the emitting circuit is emitted by the scanning module after the propagation direction is changed, and the laser pulse sequence reflected by the detector is emitted to the receiving circuit after passing through the scanning module. Alternatively, the distance measuring device may also adopt an off-axis optical path, that is, the light beam emitted by the distance measuring device and the reflected light beam are transmitted along different optical paths in the distance measuring device. Fig. 2 is a schematic diagram showing an example of a distance measuring apparatus using a coaxial optical path according to an embodiment of the present invention.

As shown in fig. 2, the ranging apparatus 200 includes a ranging module 210, and the ranging module 210 includes a transmitter 203 (which may include the transmitting circuit described above), a collimating element 204, an optical-to-electrical converter 205 (which may include the receiving circuit, the sampling circuit, and the arithmetic circuit described above), and an optical path changing element 206. The distance measuring module 210 is configured to emit a light beam, receive return light, and convert the return light into an electrical signal. Wherein the emitter 203 may be configured to emit a sequence of light pulses. In one embodiment, the transmitter 203 may emit a sequence of laser pulses. Optionally, the laser beam emitted by the emitter 203 is a narrow bandwidth beam having a wavelength outside the visible range. The collimating element 204 is disposed on an emitting light path of the emitter, and is configured to collimate the light beam emitted from the emitter 203, and collimate the light beam emitted from the emitter 203 into parallel light to be emitted to the scanning module. The collimating element is also for converging at least a portion of the return light reflected by the detector. The collimating element 204 may be a collimating lens or other element capable of collimating a light beam.

In the embodiment shown in fig. 2, the transmit and receive optical paths within the distance measuring device are combined by the optical path altering element 206 before the collimating element 204, so that the transmit and receive optical paths may share the same collimating element, making the optical path more compact. In other implementations, the emitter 203 and the photoelectric converter 205 may use respective collimating elements, and the optical path changing element 206 may be disposed on the optical path after the collimating elements.

In the embodiment shown in fig. 2, since the beam aperture of the light beam emitted from the emitter 203 is small and the beam aperture of the return light received by the distance measuring device is large, the optical path changing element can adopt a small-area mirror to combine the emission optical path and the reception optical path. In some other implementations, the optical path changing element may also use a mirror with a through hole, wherein the through hole is used for transmitting the outgoing light from the emitter 203, and the mirror is used for reflecting the return light to the photoelectric converter 205. Therefore, the shielding of the bracket of the small reflector to the return light can be reduced in the case of adopting the small reflector.

In the embodiment shown in fig. 2, the optical path altering element is offset from the optical axis of the collimating element 204. In other implementations, the optical path altering element may also be located on the optical axis of the collimating element 204.

The ranging device 200 also includes a scanning module 202. The scanning module 202 is disposed on the emitting light path of the distance measuring module 210, and the scanning module 202 is configured to change the transmission direction of the collimated light beam 219 emitted by the collimating element 204, project the collimated light beam to the external environment, and project the return light beam to the collimating element 204. The return light is converged by the collimating element 204 onto the photoelectric converter 205.

In one embodiment, the scanning module 202 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 optical element includes at least one light refracting element having non-parallel exit and entrance faces, for example. For example, the scanning module 202 includes a lens, mirror, prism, galvanometer, grating, liquid crystal, Optical Phased Array (Optical Phased Array), or any combination thereof. In one example, at least a portion of the optical element is moved, for example, by a driving module, and the moved 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 202 may rotate or oscillate about a common axis 209, with each rotating or oscillating optical element serving to constantly change the direction of propagation of an incident beam. In one embodiment, the multiple optical elements of the scanning module 202 may rotate at different rotational speeds or oscillate at different speeds. In another embodiment, at least some of the optical elements of the scanning module 202 may rotate at substantially the same rotational speed. In some embodiments, the multiple optical elements of the scanning module may also be rotated about different axes. In some embodiments, the multiple optical elements of the scanning module may also rotate in the same direction, or in different directions; or in the same direction, or in different directions, without limitation.

In one embodiment, the scanning module 202 includes a first optical element 214 and a driver 216 coupled to the first optical element 214, the driver 216 configured to drive the first optical element 214 to rotate about the rotation axis 209, such that the first optical element 214 redirects the collimated light beam 219. The first optical element 214 projects the collimated beam 219 into different directions. In one embodiment, the angle between the direction of the collimated beam 219 after it is altered by the first optical element and the axis of rotation 209 changes as the first optical element 214 is rotated. In one embodiment, the first optical element 214 includes a pair of opposing non-parallel surfaces through which the collimated light beam 219 passes. In one embodiment, the first optical element 214 includes a prism having a thickness that varies along at least one radial direction. In one embodiment, the first optical element 214 comprises a wedge angle prism that refracts the collimated beam 219.

In one embodiment, the scanning module 202 further comprises a second optical element 215, the second optical element 215 rotating around a rotation axis 209, the rotation speed of the second optical element 215 being different from the rotation speed of the first optical element 214. The second optical element 215 is used to change the direction of the light beam projected by the first optical element 214. In one embodiment, the second optical element 215 is coupled to another driver 217, and the driver 217 drives the second optical element 215 to rotate. The first optical element 214 and the second optical element 215 may be driven by the same or different drivers, such that the first optical element 214 and the second optical element 215 rotate at different speeds and/or turns, thereby projecting the collimated light beam 219 into different directions in the ambient space, which may scan a larger spatial range. In one embodiment, the controller 218 controls the driver 216 and the driver 217 to drive the first optical element 214 and the second optical element 215, respectively. The rotation speed of the first optical element 214 and the second optical element 215 can be determined according to the region and the pattern expected to be scanned in the actual application. The

drivers

216 and 217 may include motors or other drivers.

In one embodiment, second optical element 215 includes a pair of opposing non-parallel surfaces through which the light beam passes. In one embodiment, second optical element 215 includes a prism having a thickness that varies along at least one radial direction. In one embodiment, second optical element 215 comprises a wedge angle prism.

In one embodiment, the scan module 202 further comprises a third optical element (not shown) and a driver for driving the third optical element to move. Optionally, the third optical element comprises a pair of opposed non-parallel surfaces through which the light beam passes. In one embodiment, the third optical element comprises a prism having a thickness that varies along at least one radial direction. In one embodiment, the third optical element comprises a wedge angle prism. At least two of the first, second and third optical elements rotate at different rotational speeds and/or rotational directions.

In one embodiment, the scanning module comprises 2 or 3 photorefractive elements arranged in sequence on an outgoing light path of the optical pulse sequence. Optionally, at least 2 of the photorefractive elements in the scanning module rotate during scanning to change the direction of the sequence of light pulses.

The scanning module has different scanning paths at least part of different time instants, and the rotation of each optical element in the scanning module 202 can project light into different directions, such as the direction of the projected light 211 and the direction 213, so as to scan the space around the distance measuring device 200. When the light 211 projected by the scanning module 202 hits the detection object 201, a part of the light is reflected by the detection object 201 to the distance measuring device 200 in the opposite direction to the projected light 211. The return light 212 reflected by the object 201 passes through the scanning module 202 and then enters the collimating element 204.

The photoelectric converter 205 is placed on the same side of the collimating element 204 as the emitter 203, and the photoelectric converter 205 is used to convert at least part of the return light passing through the collimating element 204 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 203, which can increase the intensity of the transmitted light beam.

In one embodiment, a filter layer is coated on a surface of a component in the distance measuring device, which is located on the light beam propagation path, or a filter is arranged on the light beam propagation path, and is used for transmitting at least a wave band in which the light beam emitted by the emitter is located and reflecting other wave bands, so as to reduce noise brought to the receiver by ambient light.

In some embodiments, the transmitter 203 may include a laser diode through which laser pulses in the order of nanoseconds are emitted. Further, the laser pulse reception 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 manner, the ranging apparatus 200 may calculate the TOF207 using the pulse reception time information and the pulse emission time information, thereby determining the distance of the probe 201 to the ranging apparatus 200. The distance and orientation detected by ranging device 200 may be used for remote sensing, obstacle avoidance, mapping, modeling, navigation, and the like.

In summary, according to the distance measuring device 100 of the embodiment of the invention, in the time range of the light pulse signal emitted by the currently turned on light emitter, in addition to turning on the first receiving circuit corresponding to the currently turned on light emitter, the second receiving circuit is also turned on at the same time, and the optical signals received by the first receiving circuit and the second receiving circuit are compared to determine whether the optical signals received by the first receiving circuit are noise, so as to improve the anti-interference performance of the distance measuring device.

Another aspect of the embodiments of the present invention provides a distance measuring method. Fig. 6 shows a flow diagram of a ranging method 600. The distance measuring method 600 may be implemented by the distance measuring device according to any of the embodiments described above. Only the main steps of the ranging method 600 are described below, and some of the above detailed details are omitted.

As shown in fig. 6, the ranging method 600 includes the following steps:

in step S610, turning on the optical transmitter to transmit the optical pulse signal;

in step S620, simultaneously turning on a first receiving circuit and a second receiving circuit, where the first receiving circuit receives at least part of the echo signals of the optical pulse signals after being converged by the optical system;

in step S630, it is determined whether the first optical signal is noise according to the intensities of the first optical signal and a second optical signal, where the first optical signal and the second optical signal are respectively optical signals received by the first receiving circuit and the second receiving circuit in the same time period.

As an example, in step S630, the determining whether the first optical signal is noise according to the intensities of the first optical signal and the second optical signal includes:

and if the ratio of the intensities of the first optical signal and the second optical signal is less than or equal to a first threshold value, judging that the first optical signal is noise.

As an example, the first threshold value ranges from (0, 3%).

and if the intensity ratio of the first optical signal to the second optical signal is between a second threshold and a third threshold, judging that the first optical signal is not noise, wherein the second threshold is smaller than the third threshold.

Wherein the second threshold is greater than the first threshold.

and if the ratio of the first optical signal to the second optical signal is greater than or equal to a fourth threshold, judging that the first optical signal is noise. Wherein the third threshold is smaller than the fourth threshold, and the fourth threshold can be determined according to the intensity of the light pulse signal emitted by each light emitter.

In one embodiment, the first receiving circuit comprises a first optical-to-electrical converter, and the method comprises receiving an optical signal by the first optical-to-electrical converter and converting the optical signal into an electrical signal; the distance measuring device further comprises a first sampling circuit, the first sampling circuit is connected with the first receiving circuit and the processing module, the method further comprises the step of sampling the electric signal through the first sampling circuit to obtain a sampling signal, the sampling signal is sent to the processing module, and the processing module determines the intensity of the optical signal according to the sampling signal.

In one embodiment, the first receiving circuit further includes a current-voltage conversion circuit, and the method further includes converting, by the current-voltage conversion circuit, a current signal output by the first photoelectric converter into a voltage signal, and sending the voltage signal to the first sampling circuit, the current-voltage conversion circuit being connected to the first photoelectric converter and the first sampling circuit.

In one embodiment, the second receiving circuit comprises a second optical-to-electrical converter, the method further comprising receiving an optical signal by the second optical-to-electrical converter and converting the optical signal to an electrical signal; the distance measuring device further comprises a second sampling circuit, the second sampling circuit is connected with the second receiving circuit and the processing module, the method further comprises the step of sampling the electric signal output by the second receiving circuit through the second sampling circuit to obtain a sampling signal, the sampling signal is sent to the processing module, and the processing module determines the intensity of the optical signal according to the sampling signal.

In one embodiment, the second receiving circuit further includes a current-voltage conversion circuit connected to the second photoelectric converter and the second sampling circuit, and the method further includes converting, by the current-voltage conversion circuit, a current signal output by the second photoelectric converter into a voltage signal, and transmitting the voltage signal to the second sampling circuit.

In one embodiment, each of the receiving circuits includes an opto-electrical converter, and ranging method 600 includes receiving an optical signal by the opto-electrical converter and converting the optical signal to an electrical signal, the opto-electrical converter including a first opto-electrical converter in the first receiving circuit and a second opto-electrical converter in the second receiving circuit; the distance measuring method 600 further includes sampling the electrical signal by a sampling circuit to obtain a sampling signal, and sending the sampling signal to the processing module, the processing module determining the intensity of the optical signal according to the sampling signal, the sampling circuit being respectively connected to the receiving circuit and the processing module, the sampling circuit including a first sampling circuit connected to the first receiving circuit and a second sampling circuit connected to the second receiving circuit.

In one embodiment, the distance measuring method 600 further includes converting a current signal output from the photoelectric converter into a voltage signal by a current-voltage conversion circuit in the receiving circuit, and sending the voltage signal to the sampling circuit, the current-voltage conversion circuit being connected to the photoelectric converter and the sampling circuit.

In one embodiment, the current-to-voltage conversion circuit comprises a transimpedance amplifier, and ranging method 600 comprises turning on, or turning off, a receive circuit comprising the transimpedance amplifier via the transimpedance amplifier.

In one embodiment, the receiving circuit comprises more than two of the second receiving circuits, each of which multiplexes one of the second sampling circuits. Further, the receiving circuit may further include a third receiving circuit that is turned off in the same period of time that the first receiving circuit and the second receiving circuit are turned on. Furthermore, the number of the third receiving circuits is at least two, the first receiving circuit and at least one third receiving circuit multiplex the same first sampling circuit, and/or the second receiving circuit and the rest at least one third receiving circuit multiplex the same second sampling circuit.

Illustratively, the first photoelectric converter is disposed adjacent to the second photoelectric converter. In one embodiment, the photoelectric converters of the first receiving circuit and the third receiving circuit which multiplex the same first sampling circuit are arranged at intervals, and the photoelectric converters of the second receiving circuit and the third receiving circuit which multiplex the same second sampling circuit are arranged at intervals. For example, the photoelectric converter of the second receiving circuit is provided between the photoelectric converters of the first receiving circuit and the third receiving circuit that multiplex the same first sampling circuit.

In one embodiment, the receiving circuit is connected to a switch, and the ranging method 600 further comprises turning on the receiving circuit connected to the switch or turning off the receiving circuit connected to the switch via the switch.

In one embodiment, the first receiving circuit comprises a first optical-to-electrical converter, the second receiving circuit comprises a second optical-to-electrical converter, and the first optical-to-electrical converter and the second optical-to-electrical converter are configured to receive an optical signal; the optical system includes an optical path altering element, and ranging method 600 includes altering an optical path of an optical signal incident thereon by the optical path altering element such that the optical signal is received by the opto-electrical converter; wherein a ratio of a distance between the first photoelectric converter and the second photoelectric converter to a focal length of the optical path changing element is not more than 1/6.

Illustratively, the optical system includes an optical path changing element for changing an optical path of an optical signal incident thereon so that the optical signal is received by the first receiving circuit, wherein a focal length of the optical path changing element is between 28 millimeters and 32 millimeters.

Illustratively, the first receiving circuit includes a first photoelectric converter, the second receiving circuit includes a second photoelectric converter, the first photoelectric converter and the second photoelectric converter are used for receiving optical signals, and the distance between the first photoelectric converter and the second photoelectric converter is between 0.3 mm and 2 mm.

In one embodiment, the method further comprises receiving an optical signal by at least three optical-to-electrical converters and converting the optical signal into an electrical signal, wherein at least a portion of the optical-to-electrical converters are equally spaced and/or at least a portion of the optical-to-electrical converters are unequally spaced.

Illustratively, the directions of the light pulse signals emitted by different light emitters are the same or different. The plurality of light emitters are packaged together or individually.

In one embodiment, if the first optical signal is determined to be noise, the distance measuring method 600 further includes: and filtering the first optical signal. If it is determined that the first optical signal is not noise, the distance measuring method 600 may further include measuring a distance based on the first optical signal based on a light flight time or based on a phase shift.

According to the distance measuring method 600 of the embodiment of the invention, in the time range of the light pulse signal emitted by the currently-turned-on light emitter, the first receiving circuit corresponding to the currently-turned-on light emitter is turned on, and the second receiving circuit is also turned on at the same time, and the optical signals received by the first receiving circuit and the second receiving circuit are compared to judge whether the signals received by the first receiving circuit are noises, so that the accuracy of the distance measuring method is improved.

The embodiment of the invention also provides a movable platform, which comprises any one of the distance measuring devices and a movable platform body, wherein the distance measuring device is carried on the movable platform body. In some embodiments, the movable platform may operate fully autonomously or semi-autonomously. In some embodiments, the movable platform may operate semi-autonomously in response to one or more commands from a remote control, or may operate fully autonomously following preset program commands.

Further, the movable platform includes, but is not limited to, at least one of an automobile, a remote control car, an aircraft, and a robot. The car may be an autonomous or semi-autonomous car, and the aircraft may be an unmanned aerial vehicle, such as a fixed wing drone, a rotor drone, or the like. When the movable platform is an aircraft, the movable platform body is a fuselage of the aircraft. When the movable platform is an automobile, the movable platform body is the automobile body of the automobile. When the movable platform is a remote control car, the movable platform body is a car body of the remote control car. When the movable platform is a robot, the platform body is a robot body.

The movable platform can control the movement of the movable platform body according to the distance measurement result of the distance measurement device. For example, in a road scene, after the distance measuring device obtains the point cloud data, the movable platform can predict the relevant attributes of the obstacles according to the point cloud data, so that the detection and the segmentation of the foreground obstacles are realized, and then the track prediction of the obstacles is carried out, so that the track prediction is used as a judgment basis for the driving planning; the passable space detection can be realized according to the point cloud height and the continuity information of travelable roads, intersections and the like, or the point cloud information can be matched with a high-precision map, so that high-precision positioning is realized.

Because the distance measuring device provided by the embodiment of the invention has higher anti-interference performance, the movable platform adopting the distance measuring device also has similar advantages.

Although the illustrative embodiments have been described herein with reference to the accompanying drawings, it is to be understood that the foregoing illustrative embodiments are merely exemplary and are not intended to limit the scope of the invention thereto. Various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the scope or spirit of the present invention. All such changes and modifications are intended to be included within the scope of the present invention as set forth in the appended claims.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described device embodiments are merely illustrative, and for example, the division of the units is only one logical functional division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another device, or some features may be omitted, or not executed.

In the description provided herein, numerous specific details are set forth. It is understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Similarly, it should be appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the invention and aiding in the understanding of one or more of the various inventive aspects. However, the method of the present invention should not be construed to reflect the intent: that the invention as claimed requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

It will be understood by those skilled in the art that all of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or elements of any method or apparatus so disclosed, may be combined in any combination, except combinations where such features are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.

Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the claims, any of the claimed embodiments may be used in any combination.

The various component embodiments of the invention may be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. Those skilled in the art will appreciate that a microprocessor or Digital Signal Processor (DSP) may be used in practice to implement some or all of the functionality of some of the modules according to embodiments of the present invention. The present invention may also be embodied as apparatus programs (e.g., computer programs and computer program products) for performing a portion or all of the methods described herein. Such programs implementing the present invention may be stored on computer-readable media or may be in the form of one or more signals. Such a signal may be downloaded from an internet website or provided on a carrier signal or in any other form.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The usage of the words first, second and third, etcetera do not indicate any ordering. These words may be interpreted as names.

Claims

1. A ranging device, comprising: a light emitter, an optical system, a first receiving circuit, a second receiving circuit, and a processing module,

the light emitter is used for sequentially emitting light pulse signals; at least part of echo signals of the optical pulse signals reflected by the object are collected by the optical system and then received by the first receiving circuit;

2. The range finder device according to claim 1, wherein said determining whether the first optical signal is noise according to the strength of the first optical signal and the second optical signal comprises:

if the ratio of the intensities of the first optical signal and the second optical signal is less than or equal to a first threshold, the first optical signal is noise.

3. The ranging apparatus according to claim 2, wherein the first threshold value has a value range of (0, 3%).

4. A ranging apparatus as claimed in any of claims 1 to 3 wherein said determining whether said first optical signal is noise based on the strength of said first optical signal and said second optical signal comprises:

the first optical signal is not noise if the intensity ratio of the first optical signal to the second optical signal is between a second threshold and a third threshold, wherein the second threshold is less than the third threshold.

5. A ranging apparatus as claimed in claim 4, characterized in that said second threshold value is greater than said first threshold value.

6. The range finder device according to any one of claims 1 to 5, wherein said determining whether the first optical signal is noise according to the intensity of the first optical signal and the second optical signal comprises:

if the ratio of the first optical signal to the second optical signal is greater than or equal to a fourth threshold, the first optical signal is noise.

7. The ranging apparatus of claim 6, wherein the third threshold is less than the fourth threshold.

8. A ranging apparatus as claimed in claim 6 wherein the fourth threshold is determined in dependence on the strength of the light pulse signal emitted by each of the light emitters.

9. A ranging apparatus as claimed in claim 1 wherein the first receiving circuit comprises a first opto-electric converter for receiving an optical signal and converting the optical signal into an electrical signal;

the distance measuring device further comprises a first sampling circuit, the first sampling circuit is connected with the first receiving circuit and the processing module and used for sampling the electric signals output by the first receiving circuit to obtain sampling signals and sending the sampling signals to the processing module, and the processing module determines the intensity of the optical signals according to the sampling signals.

10. The distance measuring device of claim 9, wherein the first receiving circuit further comprises a current-voltage converting circuit, the current-voltage converting circuit is connected to the first photoelectric converter and the first sampling circuit, and is configured to convert a current signal output by the first photoelectric converter into a voltage signal and send the voltage signal to the first sampling circuit.

11. A ranging device as claimed in any of claims 1-10 wherein the second receiving circuit comprises a second opto-electric converter for receiving an optical signal and converting the optical signal into an electrical signal;

the distance measuring device further comprises a second sampling circuit, the second sampling circuit is connected with the second receiving circuit and the processing module, and is used for sampling the electric signal output by the second receiving circuit to obtain a sampling signal and sending the sampling signal to the processing module, and the processing module determines the intensity of the optical signal according to the sampling signal;

the second receiving circuit further comprises a current-voltage conversion circuit, and the current-voltage conversion circuit is connected with the second photoelectric converter and the second sampling circuit, and is used for converting a current signal output by the second photoelectric converter into a voltage signal and sending the voltage signal to the second sampling circuit.

12. A ranging apparatus as claimed in claim 10 or 11 wherein the current to voltage conversion circuit comprises a transimpedance amplifier, the transimpedance amplifier being further configured to turn on or off a receiving circuit comprising the transimpedance amplifier.

13. A ranging apparatus as claimed in any of claims 1-12 further comprising a third receiving circuit, the third receiving circuit being turned off during the same period that the first receiving circuit and the second receiving circuit are on.

14. A ranging apparatus as claimed in claim 13, characterized in that there are at least two third receiving circuits, and the first receiving circuit multiplexes the same first sampling circuit with at least one of the third receiving circuits and/or the second receiving circuit multiplexes the same second sampling circuit with the remaining at least one of the third receiving circuits.

15. A ranging device as claimed in claim 13 or 14 wherein the first photoelectric converter is located adjacent the second photoelectric converter.

16. The ranging apparatus according to claim 15, wherein the first receiving circuit and the third receiving circuit connected to the same first sampling circuit are arranged at intervals, and the second receiving circuit and the third receiving circuit connected to the same second sampling circuit are arranged at intervals.

17. The ranging apparatus according to claim 16, wherein the photoelectric converters of the first receiving circuit and the third receiving circuit connected to the same first sampling circuit are arranged at intervals, and the ranging apparatus comprises:

the photoelectric converter of the second receiving circuit is provided between the first receiving circuit connected to the same first sampling circuit and the photoelectric converter of the third receiving circuit.

18. The ranging apparatus as claimed in claim 1, further comprising a switch connected to the receiving circuit, wherein the switch is configured to turn on the receiving circuit connected to the switch or turn off the receiving circuit connected to the switch.

19. A ranging apparatus as claimed in claim 1 wherein the first receiving circuit comprises a first opto-electric converter and the second receiving circuit comprises a second opto-electric converter, the first and second opto-electric converters being arranged to receive optical signals; the optical system includes an optical path changing element for changing an optical path of an optical signal incident thereon so that the optical signal is received by the first photoelectric converter;

the ratio of the distance between the first photoelectric converter and the second photoelectric converter to the focal length of the optical path changing element is not more than 1/6.

20. A ranging apparatus as claimed in claim 1 wherein the optical system comprises an optical path altering element for altering the optical path of an optical signal incident thereon such that the optical signal is received by the first receiving circuit, wherein the optical path altering element has a focal length between 28 mm and 32 mm.

21. A ranging device as claimed in claim 1, characterized in that the first receiving circuit comprises a first opto-electric converter and the second receiving circuit comprises a second opto-electric converter, the first and second opto-electric converters being adapted to receive optical signals, wherein the distance between the first and second opto-electric converters is between 0.3 and 2 mm.

22. A ranging device as claimed in claim 1, characterized in that the receiving circuit comprises at least three opto-electric converters for receiving optical signals and converting the optical signals into electrical signals, wherein at least some of the opto-electric converters are present in an equally spaced arrangement and/or at least some of the opto-electric converters are present in an unequally spaced arrangement.

23. A ranging device as claimed in claim 1, characterized in that the directions of the light pulse signals emitted by different light emitters are the same or different.

24. A ranging apparatus as claimed in claim 1 wherein a plurality of the light emitters are packaged together or separately.

25. The range finder device of any one of claims 1-24, wherein the processing module is further configured to filter the first optical signal if the first optical signal is determined to be noise.

26. A method for ranging, the method comprising:

turning on a light emitter to emit a light pulse signal;

27. The method of claim 26, wherein the determining whether the first optical signal is noise according to the strength of the first optical signal and the second optical signal comprises:

28. The range finding method of claim 27 wherein the first threshold value ranges from (0, 3').

29. The method of any one of claims 26-28, wherein said determining whether the first optical signal is noise based on the strength of the first optical signal and the second optical signal comprises:

30. The range finding method of claim 29 wherein the second threshold is greater than the first threshold.

31. The method according to any one of claims 26 to 30, wherein the determining whether the first optical signal is noise according to the strength of the first optical signal and the second optical signal comprises:

32. The ranging method of claim 31, wherein the third threshold is less than the fourth threshold.

33. A method as claimed in claim 31, wherein the fourth threshold is determined in dependence on the strength of the light pulse signal emitted by each of the light emitters.

34. A method as claimed in claim 26, wherein the first receiving circuit comprises a first opto-electric transducer, the method comprising receiving an optical signal by the first opto-electric transducer and converting the optical signal into an electrical signal;

the distance measuring device further comprises a first sampling circuit, the first sampling circuit is connected with the first receiving circuit and the processing module, the method further comprises the step of sampling the electric signal through the first sampling circuit to obtain a sampling signal, the sampling signal is sent to the processing module, and the processing module determines the intensity of the optical signal according to the sampling signal.

35. The distance measuring method according to claim 34, wherein the first receiving circuit further comprises a current-voltage conversion circuit, the method further comprising converting a current signal output from the first photoelectric converter into a voltage signal by the current-voltage conversion circuit, and sending the voltage signal to the first sampling circuit, the current-voltage conversion circuit being connected to the first photoelectric converter and the first sampling circuit.

36. A method as claimed in any one of claims 26 to 35 wherein the second receiving circuit comprises a second opto-electrical converter, the method further comprising receiving an optical signal by the second opto-electrical converter and converting the optical signal into an electrical signal;

the distance measuring device further comprises a second sampling circuit, the second sampling circuit is connected with the second receiving circuit and the processing module, the method further comprises the step of sampling an electric signal output by the second receiving circuit through the second sampling circuit to obtain a sampling signal, the sampling signal is sent to the processing module, and the processing module determines the intensity of the optical signal according to the sampling signal;

the second receiving circuit further comprises a current-voltage conversion circuit, the current-voltage conversion circuit is connected with the second photoelectric converter and the second sampling circuit, and the method further comprises converting a current signal output by the second photoelectric converter into a voltage signal through the current-voltage conversion circuit, and sending the voltage signal to the second sampling circuit.

37. The method of claim 35 or 36, wherein the current to voltage conversion circuit comprises a transimpedance amplifier, the method further comprising turning on or turning off a receive circuit comprising the transimpedance amplifier via the transimpedance amplifier.

38. A ranging apparatus as claimed in any of claims 26 to 37 further comprising a third receive circuit which is switched off during the same time period that the first receive circuit and the second receive circuit are switched on.

39. The method according to claim 38, wherein there are at least two third receiving circuits, and the first receiving circuit and at least one of the third receiving circuits multiplex the same first sampling circuit, and/or the second receiving circuit and the remaining at least one of the third receiving circuits multiplex the same second sampling circuit.

40. A method as claimed in claim 38 or 39, wherein the first photoelectric converter is located adjacent to the second photoelectric converter.

41. The distance measuring method according to claim 40, wherein said first receiving circuit and said third receiving circuit connected to the same first sampling circuit are arranged at intervals, and said second receiving circuit and said third receiving circuit connected to the same second sampling circuit are arranged at intervals.

42. The distance measuring method according to claim 41, wherein said photoelectric converters of said first receiving circuit and said third receiving circuit connected to the same first sampling circuit are arranged at intervals, and comprise:

43. The method of claim 26, wherein the receiving circuit is connected to a switch, and wherein the method further comprises turning on the receiving circuit connected to the switch or turning off the receiving circuit connected to the switch via the switch.

44. The range finding method of claim 26 wherein the first receiving circuit comprises a first opto-electric converter and the second receiving circuit comprises a second opto-electric converter, the first and second opto-electric converters being configured to receive optical signals; the optical system includes an optical path changing element for changing an optical path of an optical signal incident thereon so that the optical signal is received by the photoelectric converter;

45. A ranging method as claimed in claim 26 wherein the optical system comprises an optical path altering element for altering the optical path of an optical signal incident thereon such that the optical signal is received by the first receiving circuit, wherein the optical path altering element has a focal length between 28 mm and 32 mm.

46. The method of ranging of claim 26, wherein the first receiving circuit comprises a first photoelectric converter and the second receiving circuit comprises a second photoelectric converter, the first photoelectric converter and the second photoelectric converter being configured to receive optical signals, wherein a distance between the first photoelectric converter and the second photoelectric converter is between 0.3 mm and 2 mm.

47. A ranging method as claimed in claim 26, characterized in that the receiving circuit comprises at least three photoelectric converters for receiving optical signals and converting the optical signals into electrical signals, wherein at least some of the photoelectric converters are present in an equally spaced arrangement and/or at least some of the photoelectric converters are present in an unequally spaced arrangement.

48. A method as claimed in claim 26, wherein the direction of the light pulse signals emitted by different light emitters is the same or different.

49. A method as claimed in claim 26, wherein a plurality of said light emitters are packaged together or separately.

50. A ranging method as claimed in any of claims 26-49, characterized in that the method further comprises: and if the first optical signal is judged to be noise, filtering the first optical signal.

51. A movable platform, comprising:

a movable platform body;

a ranging apparatus as claimed in any of claims 1 to 25 carried on the moveable platform body.

52. The movable platform of claim 51, wherein the movable platform controls movement of the movable platform body according to a ranging result of the ranging device.

53. The movable platform of claim 51, wherein the movable platform comprises at least one of an automobile, a remote control car, an aircraft, and a robot.