CN217820832U - Laser radar's transmission module, receiving module and laser radar - Google Patents
Laser radar's transmission module, receiving module and laser radar Download PDFInfo
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Abstract
The application discloses laser radar's transmission module, receiving module and laser radar. The transmitting module of the laser radar comprises a plurality of lasers, each laser respectively transmits laser beams with specified wavelengths, and the wavelengths of the laser beams transmitted by the lasers are different from each other; and a multiplexer, an amplifier, and a wavelength division device arranged in this order on the downstream side of the plurality of lasers along the transmission path of the laser beam emitted from the laser. This application can launch the laser beam of different wavelengths through a plurality of lasers, and the laser beam of different wavelengths is after the measured object reflection, is received respectively by a plurality of receivers. Each receiver in the plurality of receivers only receives the laser beams with the specified wavelength and does not receive the laser beams with other wavelengths, so that when the laser beams with different wavelengths respectively scan different view fields, the problem of crosstalk among different view fields of the laser radar is avoided.
Description
Technical Field
The application relates to the technical field of laser radars, in particular to a laser radar's emission module, receiving module and including this emission module and receiving module's laser radar.
Background
The lidar is a device that measures parameters such as distance and speed of a target object by transmitting laser light to the surface of the object and then measuring the arrival time of the reflected light beam. The laser radar mainly comprises a transmitting module, a receiving module, an information processing system, a scanning system and the like. The transmitting module adopts a laser as a transmitting light source and transmits a laser beam (scanning beam); a receiver is used to receive the reflected echo of the emitted laser beam. The maximum scanning range of the laser beam emitted by the laser is the emission field of view of the laser and the detection range of the laser; the maximum range of the receiver capable of receiving the laser echo is the receiving field of view of the receiver.
With the widespread use of lidar, there are more and more scenarios in which it is desirable for the lidar to be able to operate with a larger detection range. In order to extend the detection range of the laser radar, there is a technique of: a plurality of lasers and a plurality of receivers are arranged in the same laser radar, each laser scans different view fields respectively, and each receiver correspondingly receives the view fields scanned by the lasers. The plurality of view fields received by the receiver are spliced, so that the large view field of the laser radar is realized, and the use requirement of a large detection range is met.
SUMMERY OF THE UTILITY MODEL
Technical problem to be solved by the present application
As described above, in a scheme in which a large field of view of the lidar is achieved by a plurality of lasers and a plurality of receivers in combination, it is desirable that one reception field of view of the lidar corresponds to one transmission field of view. This can be achieved when the object surface scanned by the lidar has diffuse reflective properties. However, when the surface of an object scanned by the laser radar has retro-reflection characteristics, during the multi-field scanning of the laser radar, echoes including laser light in other transmitting fields in one receiving field occur, and when echoes (optical signals) from other transmitting fields are received in one receiving field, crosstalk occurs. Due to the existence of crosstalk, a ghost image is formed in a receiving view field (namely, the receiving view field scans an object which does not exist originally in a detection area corresponding to the receiving view field), so that misjudgment of radar signals is caused, further misjudgment of the object and the like in the detection area is caused, and the reliability of the laser radar is reduced.
The present application is developed in order to solve the above technical problem, and an object thereof is to provide a laser radar's transmitting module, receiving module and a laser radar including the transmitting module and receiving module, so that when laser beams with different wavelengths are used to scan different fields of view respectively, the crosstalk problem generated between different receiving fields of view is avoided.
Means for solving the problems
A first aspect of the present application provides a lidar's transmission module, and in some embodiments, lidar's transmission module includes: a plurality of lasers, each of which emits a laser beam having a predetermined wavelength, the wavelengths of the laser beams emitted from the respective lasers being different from each other; and a multiplexer, an amplifier, and a wavelength division device arranged in this order on the downstream side of the plurality of lasers along the transmission path of the laser beam emitted from the laser.
Because the plurality of lasers respectively emit the laser beams with different wavelengths, when the laser beams with different wavelengths scan different fields of view, each receiver is controlled to respectively receive the laser beams of the corresponding laser according to the wavelengths of the laser emitted by each laser, so that the crosstalk among the receiving fields of view caused by the emission of the laser with single wavelength and the ghost problem caused by the crosstalk can be avoided. Because the multiplexer and the wavelength division device are arranged at the downstream side of the laser in the laser beam transmission path, the amplification of laser beams with different wavelengths can be completed by using a common amplifier between the multiplexer and the wavelength division device, the amplified laser beams can realize detection, distance measurement and the like at longer distance, the number of parts and the volume of a transmitting module are reduced by the common use of the amplifier, and the structure of the laser radar is more integrated and compact. Moreover, the efficiency of the radar can be reduced while the amplification efficiency of the laser is increased by adopting the shared amplifier.
In some embodiments, the input of the multiplexer receives the laser beams emitted by each of the plurality of lasers, the output of the multiplexer is connected to one end of an optical fiber, the other end of the optical fiber is connected to the input of the amplifier, and the output of the amplifier is connected to the input of the wavelength divider.
In a launch module, a multiplexer is typically a component that couples multiple lasers launched by a laser into an optical fiber, so that the output of the multiplexer is connected to one end of one optical fiber. In addition, since the optical fiber can transmit light, the other end of the optical fiber connected with the multiplexer is connected with the input end of the amplifier, so that the coupled light can be transmitted to the amplifier and amplified by the amplifier; furthermore, since only one optical fiber is used, it contributes to reduction in the number of parts in the transmission module and miniaturization. In addition, the output end of the amplifier is connected with the input end of the wave divider, so that the coupling light after being amplified can be decoupled, and the separate transmission of each path of laser is ensured.
In some embodiments, a gain flattening filter is further disposed between the amplifier and the wavelength division device along the transmission path of the laser beam.
Since the gain flattening filter is disposed on the downstream side of the amplifier, the gains of the laser beams of different wavelengths amplified by the amplifier can be made uniform, and uniform amplification of the laser beams of different wavelengths can be achieved.
In some embodiments, one amplifier is provided for each laser beam emitted by each laser.
Because the laser beams emitted by all the lasers can share one amplifier, the number of parts of the emitting module can be reduced, and the space is saved.
In some embodiments, each laser is a seed laser.
Since the laser is a seed laser, the laser beam output by the seed laser can be injected into a downstream amplifier, so that the laser beam can be amplified.
In some embodiments, each laser is a narrow linewidth laser, and the prescribed wavelength is selected from a range of wavelengths that the rare earth doped gain fiber can amplify.
In the laser radar, the narrow linewidth laser has the advantages of narrow linewidth, high spectral purity and good coherence, so that the narrow linewidth laser can be controlled to emit laser beams with different wavelengths and low noise, and the laser beams can be maintained at fixed wavelengths to complete the scanning of a measured object. In addition, the laser beam emitted from the narrow-linewidth laser has a smaller linewidth than the laser beam emitted from the other laser, and therefore even a plurality of laser beams amplified by the amplifier can be separated by the wavelength division device. On the other hand, more laser beams can be processed by one wavelength division device, so that the number of configurable lasers of the transmitting module is increased, and the scanning field of view of the laser radar is enlarged.
In some embodiments, the laser beam emitted from the emitting module is reflected in the detection region and then received by the receiving module configured with a filter, and the wavelength difference of the laser beams emitted by any two of the plurality of lasers is greater than or equal to the sum of the working wavelength width and the wavelength drift error of the filter.
Since the wavelength difference of the laser beams emitted by any two of the plurality of lasers needs to be considered as the wavelength offset error of the filter on the laser receiving side caused by temperature drift, arrangement angle and the like, the wavelength difference is set to be larger than or equal to the sum of the working wavelength width of the filter and the wavelength offset error, so that the wavelength values of the two laser beams can be ensured to have the difference capable of being distinguished even if the wavelength offset influence of the filter exists, and the laser radar can distinguish the laser beams with different wavelengths.
A second aspect of the present application provides a lidar receiving module, which in some embodiments comprises: a plurality of receivers provided in one-to-one correspondence with the plurality of lasers in the transmitting module of the laser radar according to any one of the first aspect, each of the receivers being provided with a filter for passing a laser beam having a predetermined wavelength, the predetermined wavelength being the same as the wavelength of the laser beam emitted by the laser corresponding to the receiver.
Since the plurality of receivers are provided in one-to-one correspondence with the plurality of lasers in the transmitting module of the laser radar according to any one of the first to fourth embodiments, it is possible to control each receiver to receive only the laser beam having the predetermined wavelength, and the laser beams emitted by the respective lasers are all laser beams having different wavelengths and low noise, so that it is possible to realize one-to-one correspondence of the respective receivers with the respective lasers in accordance with the respective wavelengths with high accuracy. And because the laser beams with different wavelengths scan different fields of view, the one-to-one correspondence of the receiving fields of view of the receivers and the transmitting fields of view of the transmitters can be realized, and the ghost problem caused by the fact that the receivers receive the laser beams from the non-corresponding fields of view is avoided.
In some embodiments, the filter is a narrow band filter segment.
Because the filter is the narrow band filter, the narrow band filter allows the optical signal to pass through in specific wave band, and deviate from both sides optical signal beyond this wave band and is stopped, and the passband of narrow band filter is narrower, consequently can realize the filtering effect of high accuracy, guarantees that the receiver receives the laser beam of fixed wavelength, has avoided receiving the crosstalk problem that other wavelength brought.
A third aspect of the present application provides a lidar comprising, in some embodiments, a transmit module as in any of the embodiments of the first aspect and a receive module as in any of the embodiments of the second aspect.
The beneficial effect of this application is:
in the present application, a plurality of lasers emit laser beams of different wavelengths, and the laser beams of different wavelengths are reflected by an object to be measured and then received by a plurality of receivers, respectively. Wherein, every receiver in a plurality of receivers only receives the laser beam of regulation wavelength, and can not receive the laser beam of other wavelengths to when using the laser beam of different wavelengths to scan different visual fields respectively, can not produce the crosstalk problem between laser radar's different visual fields, consequently can detect accurately, can improve laser radar's detection reliability.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the scope of the application.
Drawings
Fig. 1 is a schematic configuration diagram of a transmitting module of a laser radar according to an embodiment of the present disclosure;
fig. 2 is a schematic view illustrating a receiving module of a laser radar according to an embodiment of the present disclosure;
fig. 3 is a schematic diagram of an operating process of a laser radar according to an embodiment of the present disclosure.
Description of reference numerals:
an LD-laser; LD 1 ～LD n -first to nth lasers; 2-a multiplexer; 3-an amplifier; 4-gain flattening filter; 5-a wavelength splitter; an OUT-transmit terminal; OUT 1 ～OUT n -first to nth transmitting terminals; 7-a processing component; IN-receiver; IN 1 ～IN n -first to nth receivers; OB-the object to be tested; OB 1 ～OB n -an object to be measured in the first to nth fields of view; lambda-wavelength; lambda [ alpha ] 1 ～λ n -first to nth wavelengths; an FL-filter; FL 1 ～FL n -first to nth filters.
Detailed Description
Embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood by those skilled in the art that the specific structures, dimensions and proportions shown in the drawings are for illustrative purposes only and have been shown in enlarged detail in order to facilitate understanding of the embodiments of the present invention, and not for the purpose of limiting the scope of the invention as defined by the appended claims.
In this specification, unless clearly stated otherwise, the terms "connected", "fixed", and the like are to be understood in a broad sense, including but not limited to directly, indirectly, detachably "connected", "fixed", and the like. Unless otherwise specifically stated, the terms "upper", "lower", "left" and "right" are expressed based on the directions of the drawing planes.
Referring to the drawings in the specification, fig. 1 is a schematic structural diagram of a transmitting module of a laser radar according to an embodiment of the present disclosure.
The structure of the transmitting module of the laser radar will be described with reference to fig. 1.
The transmitting module of the laser radar of the present application mainly includes a plurality of lasers LD, and a multiplexer 2, an amplifier 3, and a wavelength division device 5 which are arranged in this order on the downstream side of the plurality of lasers LD along the transmission path of the laser beam emitted from the lasers LD. The lasers LD emit laser beams having a predetermined wavelength λ, and the wavelengths λ of the laser beams emitted by the lasers LD are different from each other. In this specification, when a plurality of lasers are explained in a differentiated manner, LD is used 1 ～LD n First to nth lasers (n is a natural number of 1 or more); collectively referred to as lasers LD when the individual lasers are not particularly distinguished; the same explanation is applied to the wavelength, the transmitting end, the receiving end, the field of view, and the filter, which will be described later.
A plurality of lasers LD are used to emit laser beams of different wavelengths λ. For example, the first to nth lasers LD 1 ～LD n Respectively emitting a first wavelength lambda 1 N wavelength lambda n Of a first wavelength lambda 1 N wavelength lambda n Are different from each other. Laser beams of different wavelengths are emitted via different emission terminals OUT. E.g. a first wavelength lambda 1 N wavelength lambda n Respectively via the first emitting terminal OUT 1 -nth transmitting terminal OUT n And emitting to form the first to nth emission fields. The first through nth emission fields of view may be at least partially overlapping fields of view or may be completely non-overlapping fields of view with respect to each other. The terms "overlap" and "non-overlap" mean spatially overlapping or non-overlapping, and may include a horizontal direction, a vertical direction, a near-far direction, and the like. The lidar can meet the field of view requirements of various application scenarios by appropriately increasing or decreasing the number of lasers LD. Therefore, the number of the lasers LD is not specifically limited in the embodiment of the present application, and may be specifically set according to an actual application scenario and the like.
Further, the arrangement of the plurality of lasers LD may be set as the case may be. For example, the field of view of the lidar and the space occupied by the lidar may be considered and set. It should be noted that the arrangement of the plurality of lasers LD needs to ensure that the laser beams emitted by the plurality of lasers LD can be transmitted to the multiplexer 2 on the downstream side, so that the multiplexer 2 can optically couple the plurality of laser beams.
As a specific example, the plurality of lasers LD may be formed in a row or a column, or may be formed in a two-dimensional or three-dimensional array.
Further, the plurality of laser LDs emit laser beams of different wavelengths, for example, laser LDs 1 ～LD n Respectively emitting a first wavelength lambda 1 N wavelength lambda n Of a first wavelength lambda 1 N wavelength lambda n Are different from each other. That is, there is a certain wavelength difference between the wavelengths of the laser beams. Here, the constant wavelength difference means that the wavelength difference between any two laser beams can be made larger than the wavelength shift error due to other members or factors (for example, the installation angle), and the thermal drift effect of a filter (for example, a filter) described later is also considered, and for example, the wavelength difference can be set to be larger than or equal to the sum of the operating wavelength width of the filter on the receiving side and the wavelength shift error. This ensures that the wavelength value of the laser beam is different from the wavelength value of the other laser beam by a difference that can be resolved by each filter and each receiver, which will be described later, even when there is a wavelength shift error and/or the influence of thermal drift of the filter, and facilitates the discrimination between the laser beam and the other laser beam. As for the specific value of the wavelength difference, those skilled in the art can set it according to the specific circumstances such as the operating wavelength width of the filter employed on the receiving side. In addition, the wavelength λ of each laser beam can be selected within a wavelength range in which the rare-earth-element-doped gain fiber can amplify.
As a specific example, assuming that the wavelength width of the filter is 5nm and the shift (wavelength shift error) that may be caused by temperature, arrangement angle, etc. is 10nm, the laser radar may set the emission wavelengths of the two laser beams to 1535nm and 1550nm, 1535nm and 1555nm, and 1550nm and 1570nm, respectively, and thus may not affect the distinction of the two laser beams even if there is a shift error.
In one embodiment, the laser may be a seed laser. The seed laser can supply the initial signal light (laser beam) which is injected into the amplifier 3 on the downstream side, achieving amplification of the initial signal light. Specifically, the seed laser used in this embodiment includes a solid-state laser seed source and a fiber laser. Taking the fiber laser as an example, the fiber laser has the advantages of small volume, low cost, high light conversion efficiency and the like. The fiber laser is used as a laser seed source for a downstream amplifier and is matched with the amplifier for use, so that laser beams meeting the requirements of more application scenes can be emitted.
The laser is preferably a narrow linewidth laser. The narrow linewidth laser generally has the advantages of narrow linewidth, high spectral purity and good coherence, so that the narrow linewidth laser can be controlled to emit laser beams with different wavelengths, and the laser beams can be maintained at a fixed wavelength to complete the scanning of a measured object.
In an embodiment, the laser radar may set the number of lasers, which may be one or more of the plurality of lasers LD, operating simultaneously according to actual application scenarios and requirements. For example, the transmitting module may include a laser LD1, a laser LD2, and a laser LD3. During the use, can set up laser LD1 and laser LD3 simultaneous working, or, can set up laser LD2 and laser LD3 simultaneous working, or, can set up laser LD1, laser LD2 and laser LD3 simultaneous working. In one embodiment, the "focus" function may be achieved by setting the operating frequency of the laser. In particular, the change to the resolution of the lidar may be referred to as "focusing" of the lidar. For example, for a specific scanning view field, such as a Region of ROI (Region of Interest) in the middle of the lidar view field, a laser with a higher operating frequency is used to scan the specific view field, so that the number of scan lines for scanning the specific view field can be increased, and the resolution of the lidar for the specific view field can be improved. In other embodiments, the range of the lidar may be varied by setting the power of the operating laser. For example, when only a few lasers are reserved for working, energy can be gathered in the few lasers, so that the emission energy of each laser is higher, the energy of a laser beam is increased, and the distance measurement is further; when most lasers are kept to work, energy can be dispersed among all the lasers, the emission energy of each laser is lower, the distance measurement is shortened, and the detection range is larger.
The multiplexer 2 is used to couple multiple lasers LD emitting multiple lasers LD together. As the multiplexer 2, laser beams of different wavelengths can be coupled to the optical fiber on the downstream side. Since the lasers with different wavelengths can be regarded as independent of each other (when the nonlinearity of the optical fiber is not considered), the lasers can be combined together to realize the multiplexing transmission of the multi-path lasers.
In one embodiment, multiplexer 2 may couple multiple laser beams into an optical fiber. For example, the input end of the multiplexer 2 receives laser beams emitted by each of the plurality of lasers LD, and the multiplexer 2 combines the laser beams and transmits the combined laser beams to the output end of the multiplexer 2. Since the output end of the multiplexer 2 is connected to one end of one optical fiber, the combined laser beam is sent into one optical fiber for transmission.
The amplifier 3 is used for amplifying the coupled light (multi-path laser) coupled by the multiplexer 2, that is, the output end of the multiplexer 2 is connected to the input end of the amplifier 3. The amplifier 3 can directly amplify an optical signal and has a real-time, high-gain, low-noise, and low-loss all-optical amplification function. Preferably, an Erbium Doped Fiber Amplifier (EDFA) may be used in this embodiment.
It should be understood that the number of amplifiers 3 may be one amplifier 3 corresponding to a plurality of lasers LD, for example, a plurality of lasers LD may be grouped, and each group corresponds to one amplifier 3; one amplifier 3 may be provided for each of the plurality of lasers.
In one embodiment, the amplifier 3 may be connected to the multiplexer 2 by an optical fiber. For example, when the output end of the multiplexer 2 is connected to one end of one optical fiber, the amplifier 3 may receive the coupled light output by the multiplexer 2 by connecting the other end of the one optical fiber.
The wave splitter 5 is used for decoupling the coupled light, realizing multipath laser separation, and coupling to each transmitting end OUT of the laser radar. The wavelength division device 5 can transmit the coupled light to the corresponding emission terminals OUT in accordance with the wavelength. The wavelength division device 5 is arranged with different outputs for laser beams of different wavelengths. A laser beam of a given wavelength can only be transmitted from its input to the corresponding output, with the other outputs having the desired isolation for the laser beam of the given wavelength.
In an embodiment, the wave splitter 5 may be connected to the amplifier 3. For example, the output end of the amplifier 3 is connected to the input end of the wave splitter 5, so that the amplified coupled light can be decoupled, and the separate transmission of each laser is ensured.
In an embodiment, a gain flattening filter 4 may be further disposed between the amplifier 3 and the wavelength division device 5 along the transmission path of the laser beam. The input end of the gain flattening filter 4 is connected with the output end of the amplifier 3, and the output end of the gain flattening filter 4 is connected with the output end of the wavelength division device 5. The gain flattening filter 4 can be used to balance the gains of the laser beams with different wavelengths, so that the gain flattening filter 4 is disposed at the downstream side of the amplifier 3, so that the gains of the laser beams with different wavelengths after being amplified by the amplifier 3 can be uniform, and uniform amplification of the laser beams with different wavelengths can be realized.
Next, a working flow of the laser radar transmitting module is described with reference to fig. 1.
First, first to nth lasers LD 1 ～LD n The emission wavelengths are respectively the first to nth wavelengths lambda 1 ～λ n The multiplexer 2 receives the first to nth wavelengths lambda 1 ～λ n And coupling the laser beams to an optical fiber. The coupled laser beam is transmitted along the optical fiber to a common one of the amplifiers 3 to perform laser beam amplification. The amplified laser beam is transmitted to the gain flattening filter 4, and the gain flattening filter 4 performs gain flattening processing on the amplification gain generated by the amplifier 3. At the gain flattening filter 4The processed laser beams are transmitted to a wave splitter 5, are decoupled in the wave splitter 5 and are respectively transmitted to a first transmitting end OUT to an n-th transmitting end OUT 1 ～OUT n And respectively emitted from the emitting terminals OUT to perform detection in the respective emitting fields of view. Specifically, the first laser LD 1 Emitted first wavelength lambda 1 From a first emitting terminal OUT 1 Sending out, and detecting the measured object in the first view field; second laser LD 2 (not shown) emitted second wavelength lambda 2 From the second emitting terminal OUT 2 (not shown) detecting the object in the second field of view; nth laser LD n Emitted nth wavelength lambda n From the n-th emitting terminal OUT n And sending out, and detecting the measured object in the nth field of view.
In the embodiment of the application, the plurality of lasers respectively emit laser beams with different wavelengths, so that when the laser beams with different wavelengths scan different view fields, each receiver is controlled to respectively receive the laser beams of the corresponding laser according to the wavelengths of the laser emitted by each laser, and therefore crosstalk between the receiving view fields caused by the emission of the laser with a single wavelength and a ghost problem caused by the crosstalk can be avoided.
Based on the same inventive concept, the embodiment of the application also provides a receiving module of the laser radar. Referring to the accompanying drawings in the specification, fig. 2 is a schematic structural diagram of a receiving module of a laser radar according to an embodiment of the present disclosure. As shown IN fig. 2, the receiving module of the laser radar of the present application mainly includes a plurality of receivers IN provided IN one-to-one correspondence with the plurality of lasers LD IN the transmitting module of the laser radar according to any one of the embodiments described above, and a plurality of filters FL arranged corresponding to the receivers IN, and each filter FL passes a laser beam having a predetermined wavelength, which is the same as the wavelength of the laser beam emitted from the laser LD corresponding to the receiver.
The filter FL is arranged upstream of the receiver IN. Upstream here means upstream of the transmission path of the laser beam echo. As indicated by the arrow IN fig. 2, the laser beam reflected by the object to be measured reaches the receivers IN after passing through the filter FL, and the multiple receivers IN can transmit the received laser beam information to the processing component 7 of the laser radar for processing. Since the filter FL allows only the laser beam of a prescribed wavelength to pass through, it is ensured that the receiver IN receives the prescribed wavelength generated by the corresponding laser LD.
For example, IN the first to nth receivers IN 1 ～IN n The first to nth filters FL are disposed at the upstream side of the filter 1 ～FL n First to nth receivers IN 1 ～IN n Respectively receive the signals from the first transmitting terminal OUT 1 -n-th transmitting terminal OUT n Emitted first wavelength lambda 1 N wavelength lambda n The first to nth fields of view reflect echoes of the laser beam respectively. First to nth filters FL 1 ～FL n Respectively allowing a first wavelength lambda 1 N wavelength lambda n Through which the laser beam passes.
It should be understood that, as described above, by providing a plurality of receivers IN one-to-one correspondence with a plurality of lasers LD, it is possible to control each receiver to receive only echoes of laser beams having different wavelengths, and IN addition, laser beams emitted by each laser are all laser beams having different wavelengths and low noise, so that it is possible to realize one-to-one correspondence of each receiver with each laser for each wavelength with high accuracy. And because the laser beams with different wavelengths scan different fields of view, the one-to-one correspondence of the receiving fields of view of the receivers and the transmitting fields of view of the transmitters can be realized, and the ghost problem caused by the fact that the receivers receive the laser beams from the non-corresponding fields of view is avoided.
Further, the arrangement of the plurality of receivers IN may be set as the case may be, as long as the first to nth receivers IN 1 ～IN n Capable of receiving the first to nth lasers LD respectively 1 ～LD n The emitted echoes reflected in the first to nth fields of view (the wavelengths are the first to nth wavelengths lambda respectively) 1 ～λ n ) And (4) finishing.
The filter may be a filter segment, preferably a narrow band filter segment. The narrow-band filter allows the optical signals to pass through at a specific waveband, the optical signals on two sides deviating from the specific waveband are prevented, and the passband of the narrow-band filter is relatively narrow, so that a good filtering effect can be realized, the receiver is ensured to receive the laser beams with fixed wavelengths, and the problem of crosstalk caused by receiving other wavelengths is avoided.
The following describes a working procedure of a receiving module of a laser radar with reference to the drawings of the specification.
Fig. 3 is a schematic diagram of an operation process of a laser radar according to an embodiment of the present disclosure. As shown in fig. 3, the first to nth wavelengths λ 1 ～λ n From the first to n-th emitting terminals OUT 1 ～OUT n And (4) sending out. First to nth wavelengths lambda 1 ～λ n The laser beams respectively detect the measured objects in the first to nth fields of view. Specifically, from the first transmission terminal OUT 1 Emitted first wavelength lambda 1 To an object OB to be measured in a first field of view 1 Detecting; from the second transmitting terminal OUT 2 (not shown in the figure) of a second wavelength lambda 2 Detects the object OB2 to be measured (not shown in the figure) in the second field of view; from the n-th transmitting terminal OUT n Emitted n-th wavelength lambda n To the object OB to be measured in the nth field of view n And (6) detecting. In this case, for example, the object OB1 in the first field of view does not generate diffuse reflection, and the object OB in the nth field of view does not generate diffuse reflection n Producing a diffuse reflection.
As shown in fig. 3, when the first wavelength λ 1 To the object OB to be measured in the first field of view 1 While, the object OB in the first field of view 1 The laser beam is reflected and the reflected laser beam passes through the allowed first wavelength lambda 1 Reaches the first receiver IN after passing through the first filter FL1 1 Realize the first wavelength lambda 1 Of the laser beam. When the nth wavelength λ n To the object OB to be measured in the nth field of view n While in the nth field of view n The laser beam will be diffusely reflected. Wherein the n-th wavelength λ of the diffuse reflection n Will be reflected to the filters FL of the plurality of receiving modules, wherein the laser beam is reflected to the n-th filter FL n N wavelength λ of n Will pass through the n-th filter FL n To the nth receiver IN n Thereby realizing the n-th wavelength lambda n Reception of an echo of the laser beam. In addition, it is reflected to the n-th filter FL n Except (reflection to the first filter FL is shown in fig. 3 1 Example of (d) of the nth wavelength λ n Filter FL (e.g., first filter FL) through which the echo of the laser beam cannot reach 1 ) And therefore not by the corresponding receiver (first receiver IN) 1 ) Receive and thus do not cause crosstalk problems.
Based on the same inventive concept, the embodiment of the present application further provides a lidar, which includes the transmitting module described in each of the embodiments and the receiving module described in each of the embodiments. That is, this application can provide the receiving module of the different wavelength of emission module and control receipt of control emission difference wavelength, when the laser beam scanning different visual fields of different wavelength, can realize that the signal between different visual fields can not produce and crosstalk.
The received echoes of the respective laser beams may be subjected to signal processing by, for example, the processing section 7 shown in fig. 2 or the like, and point cloud data is obtained based on the processing result. Therefore, point cloud data without crosstalk and ghost can be formed, and the detection accuracy and reliability of the laser radar can be improved.
It should be noted that, in the embodiment of the working process of the laser radar, reference may be made to specific descriptions in the embodiments of the transmitting module and the receiving module, and for simplicity of the description, no further description is given here.
Furthermore, the features and benefits of the present application are explained with reference to exemplary embodiments. Accordingly, the application expressly should not be limited to these exemplary embodiments illustrating some possible non-limiting combination of features that may exist alone or in other combinations of features.
Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the technology and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the application being indicated by the following claims.
Claims (10)
1. The utility model provides a laser radar's transmission module which characterized in that includes:
a plurality of lasers, each of which emits a laser beam having a predetermined wavelength, the wavelengths of the laser beams emitted from the respective lasers being different from each other; and
a multiplexer, an amplifier, and a wavelength division device arranged in this order on the downstream side of the plurality of lasers along the transmission path of the laser beam emitted from the laser.
2. The lidar transmission module of claim 1,
the input end of the multiplexer receives the laser beams emitted by each of the plurality of lasers, the output end of the multiplexer is connected to one end of an optical fiber, the other end of the optical fiber is connected to the input end of the amplifier, and the output end of the amplifier is connected to the input end of the wavelength divider.
3. The lidar transmit module of claim 2,
a gain flattening filter is further provided between the amplifier and the wavelength division device along a transmission path of the laser beam.
4. The lidar transmit module of claim 2,
the amplifier is provided with one amplifier for sharing the laser beams emitted by the lasers.
5. The lidar transmission module of claim 1,
each of the lasers is a seed laser.
6. The lidar transmission module of claim 5,
each of the lasers is a narrow linewidth laser,
the prescribed wavelength is selected from a range of wavelengths that the rare earth doped gain fiber is capable of amplifying.
7. The lidar transmission module of claim 1,
the laser beam emitted from the transmitting module is received by a receiving module provided with a filter after being reflected in a detection area,
the wavelength difference of the laser beams emitted by any two of the plurality of lasers is larger than or equal to the sum of the working wavelength width and the wavelength drift error of the filter.
8. A receiving module of a lidar characterized by comprising a plurality of receivers arranged in one-to-one correspondence with the plurality of lasers in the transmitting module of the lidar of any of claims 1 to 7,
a filter for passing a laser beam having a predetermined wavelength, which is the same as the wavelength of the laser beam emitted by the laser device corresponding to the receiver, is disposed corresponding to each receiver.
9. The lidar receiver module of claim 8,
the filter is a narrow-band filter plate.
10. Lidar comprising a transmit module according to any of claims 1 to 7 and a receive module according to any of claims 8 to 9.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115791756A (en) * | 2022-11-24 | 2023-03-14 | 北京杏林睿光科技有限公司 | Laser-induced breakdown spectroscopy device for measuring full spectrum at one time |
| WO2024045550A1 (en) * | 2022-08-29 | 2024-03-07 | 上海禾赛科技有限公司 | Laser radar transmitting module, transceiver device and laser radar |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024045550A1 (en) * | 2022-08-29 | 2024-03-07 | 上海禾赛科技有限公司 | Laser radar transmitting module, transceiver device and laser radar |
| CN115791756A (en) * | 2022-11-24 | 2023-03-14 | 北京杏林睿光科技有限公司 | Laser-induced breakdown spectroscopy device for measuring full spectrum at one time |
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