CN113219442B - Method and device for optimizing influence of laser radar photomask - Google Patents
Method and device for optimizing influence of laser radar photomask Download PDFInfo
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- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
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Abstract
The invention discloses a method and a device for optimizing the influence of a light-transmitting cover of a laser radar, wherein before the light-transmitting cover is installed on the laser radar, a light signal with preset light intensity is utilized to calibrate the light-transmitting cover, so that the light energy loss of the light-transmitting cover is obtained; after the light transmitting cover is mounted on a laser radar, detecting actual light energy by the laser radar, and calculating calibrated light energy according to the actual light energy and the light energy loss of the light transmitting cover; and determining the distance between the target and the laser radar according to the calibrated light energy. According to the scheme provided by the invention, the influence of the light transmission cover can be eliminated, and the ranging accuracy of the laser radar is improved.
Description
Technical Field
The invention belongs to the technical field of laser radars, and particularly relates to a method and a device for optimizing the influence of a laser radar photomask.
Background
The laser radar can be used for acquiring three-dimensional information of surrounding environment targets and transmitting point cloud data to a background processing system, and belongs to high-precision equipment in the photoelectric industry. The main components of the laser radar comprise a transmitting light source, a receiving detector, an optical system, a light beam scanning system, a photomask and the like. The light source is a transmitting part of laser radar detection light signals, the receiving detector is a light signal receiving part of the laser radar, the optical system is a part for performing light spot collimation and shaping, the light beam scanning part is a structure for controlling light beams to perform space scanning, and the light transmission cover is a component for sealing and protecting a laser radar optical mechanical system and enabling the light signals to pass through in a lossless manner.
The light transmission cover is not a core function index element, but is also a key component, and the performance of the light transmission cover directly influences the overall performance index of the laser radar. At present, most of the calibration and test of the laser radar are completed without a light transmission cover, namely, an emission light source, a receiving detector, an optical system and the like are assembled together, but the light transmission cover is not assembled first. After the emission light source, the receiving detector and the optical system are assembled, the system finishes calibration and testing, and after the index is qualified, the photomask is installed. At this time, the light passing mask can attenuate the detection signal light to a certain extent, and the light attenuation of the part can directly influence the distance detection precision of the laser radar, and the influence on the distance of objects with different reflectivity is inconsistent, and cannot be eliminated through secondary calibration.
Disclosure of Invention
Aiming at the defects or improvement demands of the prior art, the invention provides a method and a device for optimizing the influence of a laser radar light-transmitting cover, which aim to eliminate the influence of the light-transmitting cover during formal use and improve the ranging precision of the laser radar by pre-calibrating the light-transmitting cover before formal use.
To achieve the above object, according to one aspect of the present invention, there is provided a method of optimizing an influence of a laser radar through mask, including:
before the light transmitting cover is mounted on a laser radar, calibrating the light transmitting cover by utilizing a light signal with preset light intensity to obtain the light energy loss of the light transmitting cover;
after the light transmitting cover is mounted on a laser radar, detecting actual light energy by the laser radar, and calculating calibrated light energy according to the actual light energy and the light energy loss of the light transmitting cover;
and determining the distance between the target and the laser radar according to the calibrated light energy.
Preferably, the calibrating the light-transmitting cover by using the light signal with preset light intensity, to obtain the light energy loss of the light-transmitting cover specifically includes:
selecting one or more calibration distances, and calculating the light energy E before the light signal with preset light intensity passes through the light transmission cover under each calibration distance F And light energy E after passing through the light-transmitting mask B And uses the mapping table to store each calibration distance and corresponding light energy E F Mapping relation between the two;
using the corresponding light energy E at each calibration distance F And light energy E B And calculating a corresponding light energy loss value gamma, and further determining the light energy loss gamma' of the light transmitting mask.
Preferably, the determining the distance between the target and the laser radar according to the calibration light energy specifically includes:
and searching the mapping table according to the calibrated light energy, determining a calibrated distance corresponding to the calibrated light energy value, and further determining the distance between the target and the laser radar.
Preferably, the light energy E F Light energy E B The calculation process of (1) is specifically as follows:
sampling the echo signals with preset light intensity on a time axis, and performing curve fitting based on the intensities of the echo signals obtained by sampling to obtain a fitting function of the echo signals;
determining the starting time and the ending time of the echo signal according to the echo signal curve;
and calculating corresponding light energy according to the fitting function, the starting time and the ending time of the echo signals.
Preferably, the determining the start time and the end time of the echo signal according to the echo signal curve specifically includes:
determining the starting time and the ending time of the echo signal according to two time intersection points of the echo signal curve and the signal threshold; the smaller time point of the two time intersection points is taken as the starting time of the echo signals, and the larger time point is taken as the ending time of the echo signals.
Preferably, the determining the start time and the end time of the echo signal according to the echo signal curve specifically includes:
performing reverse time deduction on the fitting function to enable the intensity of the echo signal to approach to zero value, and further calculating the initial time of the echo signal;
forward time deduction is carried out on the fitting function, so that the intensity of the echo signal approaches to zero, and the ending time of the echo signal is calculated; or the starting time is symmetrical by utilizing the symmetry axis of the echo signal curve, and the ending time of the echo signal is determined.
Preferably, the fitting function of the echo signal is specifically as follows:
wherein V (t) represents the echo signal intensity, which changes with time; the coefficient a represents the height of the peak of the echo signal curve; the coefficient c represents the transverse expansion width of the echo signal curve on the time axis; t is t p Representing the time corresponding to the maximum value of the echo signal intensity on the echo signal curve.
Preferably, the calculation method of the corresponding light energy loss value Γ at each calibration distance specifically includes:
wherein ,t0F and t1F Before the light signals with preset light intensity pass through the light transmission cover, the starting time and the ending time of the echo signals are corresponding; t is t 0B and t1B After the light signals with preset light intensity pass through the light transmission cover, the starting time and the ending time of the echo signals are corresponding; v (V) F (t) a fitting function of a corresponding echo signal before a light signal with preset light intensity passes through the light transmission cover; v (V) B And (t) is a fitting function of the corresponding echo signals after the light signals with preset light intensity pass through the light transmission cover.
Preferably, the method further comprises:
the laser radar emits light signals with preset light intensity every preset period, and the light energy E after the light signals with preset light intensity pass through the light passing cover is calculated at any calibration distance B '；
Searching the mapping table according to the currently selected calibration distance, and determining the light energy E corresponding to the calibration distance F And based on the found light energy E F And light energy E B 'updating the light energy loss Γ' of the reticle.
According to another aspect of the present invention, there is provided an apparatus for optimizing the effect of a lidar reticle, comprising at least one processor and a memory, the at least one processor and the memory being connected by a data bus, the memory storing instructions executable by the at least one processor, the instructions, when executed by the processor, being configured to perform the method for optimizing the effect of a lidar reticle according to the first aspect.
In general, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects: in the scheme provided by the invention, before the laser radar formally installs the light-transmitting cover for use, one light intensity is preselected to calibrate the light-transmitting cover, and the energy change of the light signals before and after the light-transmitting cover is added is calculated to obtain the influence of the light-transmitting cover on the light intensity; when the laser radar is formally provided with the light-transmitting cover for use, the influence of the light-transmitting cover is utilized to carry out secondary algorithm calibration on the actually detected light signal energy, and the calibrated light signal energy is utilized to carry out distance calculation, so that the influence of the light-transmitting cover can be eliminated, and the ranging accuracy of the laser radar is improved.
Drawings
FIG. 1 is a schematic view of a use scenario of a lidar according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of an echo signal without a mask and with a mask according to an embodiment of the present invention;
FIG. 3 is a flowchart of a method for optimizing the effect of a laser radar photomask according to an embodiment of the present invention;
FIG. 4 is a schematic view of the light energy of an echo signal without and with a mask according to an embodiment of the present invention;
FIG. 5 is a schematic diagram illustrating attenuation of an optical signal before and after passing through a photomask according to an embodiment of the present invention;
FIG. 6 is a flowchart of a method for calculating light energy according to an embodiment of the present invention;
FIG. 7 is a flowchart of a method for calibrating and correcting a photomask according to an embodiment of the present invention;
fig. 8 is a device frame diagram for optimizing the influence of a laser radar photomask according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. In addition, the technical features of the embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.
In the description of the present invention, the terms "inner", "outer", "longitudinal", "transverse", "upper", "lower", "top", "bottom", "left", "right", "front", "rear", etc. refer to the orientation or positional relationship based on that shown in the drawings, merely for convenience of describing the present invention and do not require that the present invention must be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.
The use scene of the laser radar is shown in fig. 1, detection light signals with different angles are emitted from the emission light source of the laser radar, and are transmitted towards the target after passing through the photomask; after the receiving detector receives the optical signal returned by the target, the optical signal is converted into an electrical signal. When the optical signal passes through the mask, attenuation occurs, and the representation of the response at the receiving detector is that the echo signal is attenuated. As shown in fig. 2, curves 1 and 2 are photoelectric response curves (i.e., echo signal curves) without and with the reticle, respectively, with the abscissa being the time axis and the ordinate being the voltage signal of the receiving detector. As is clear from fig. 2, the overall response amplitude of curve 2 decreases, the overall height of the voltage signal decays, and there is also a reduction in the width of the signal.
When receiving an optical signal, a receiving detector of the laser radar converts the optical signal into an electric signal, but because of interference factors such as noise and the like of a system, certain bottom noise exists in the receiving system; if the echo signal is drowned out by bottom noise, the signal cannot be effectively identified. Therefore, a signal threshold is typically set for removing the bottom noise, and a signal that actually exceeds the signal threshold is used as a testable reference. When the time of flight of the echo signals is calculated, the time intersection point of the photoelectric response curves of the two echo signals and the signal threshold changes, as shown by the point A and the point B in FIG. 2, the light transmitting mask can cause a judgment error of the signal receiving time, and further the calculation of the time of flight of the echo signals is affected. Meanwhile, due to the production process and flow, part of laser radar products cannot be provided with a photomask first and then calibrated. Therefore, the problem of the echo signal flight time judgment error caused by the light transmission cover is required to be solved by other technical means.
Example 1
In order to solve the problems, the embodiment of the invention provides a method for optimizing the influence of a laser radar light-transmitting cover, which can remove the influence of the light-transmitting cover on the determination error of the flight time of an optical signal by performing reverse simulation through an algorithm. As shown in fig. 3, the method provided by the embodiment of the invention mainly includes the following steps:
and 101, calibrating the light transmitting cover by utilizing a light signal with preset light intensity before the light transmitting cover is mounted on the laser radar, so as to obtain the light energy loss of the light transmitting cover.
When the optical signal passes through the photomask, the loss of the optical signal is mainly reflected and absorbed by the optical energy, and the detector can only convert the echo signal from the optical signal into an electric signal. Therefore, it is necessary to integrate the electric signal on the time axis to obtain the energy corresponding to the optical signal, that is, the optical energy. For the light-transmitting maskThe energy loss of the optical signal is performed in proportion to each time. Therefore, the light energy E before the light signal of the preset light intensity passes through the light-passing cover can be respectively determined by detecting the light intensity in advance before the light-passing cover is installed F And light energy E after passing through the light-transmitting mask B Compared with the two light energies (E B /E F ) The light energy loss of the photomask can be determined. The specific process is as follows:
1) Selecting one or more calibration distances, and calculating the light energy E before the light signal with preset light intensity passes through the light transmission cover under each calibration distance F And light energy E after passing through the light-transmitting mask B Storing each calibration distance and corresponding light energy E by using a mapping table F Mapping relation between the two.
The more the number of calibration distances is selected, the more the number of calibration times is, the more accurate the finally obtained calibration result is, and the specific number of calibration distances can be selected according to the actual precision requirement, which is not particularly limited. At each calibration distance, the light signal with preset light intensity is directly transmitted to the calibration object, and the corresponding light energy is calculated based on the received detected echo signal, namely the light energy E before the light signal passes through the light passing mask F The method comprises the steps of carrying out a first treatment on the surface of the Transmitting the light signal with preset light intensity to the calibration object after passing through the light-passing mask, and calculating corresponding light energy based on the received detected echo signal, namely the light energy E after the light signal passes through the light-passing mask B . After each calibration, the mapping table is used for storing the corresponding calibration distance and the light energy E F Mapping relation between the two; that is, the mapping table stores a plurality of sets of mapping relation between distance and light energy, so that the mapping relation can be directly checked for use in the subsequent distance detection.
As shown in FIG. 4, curves 1 and 2 are the echo signal curves without and with the mask, respectively, and the area covered by curve 1 on the time axis is the light energy E F The area covered by the curve 2 on the time axis is the light energy E B The light energy can be calculated by the formula (1):
wherein V (t) is the echo signal intensity, t 0 and t1 Respectively representing the start time and the end time of the echo signal, t 0 To t 1 The time of flight of the echo signal is obtained.
2) Using the corresponding light energy E at each calibration distance F And light energy E B And calculating a corresponding light energy loss value gamma, and further determining the light energy loss gamma' of the light transmitting mask.
For a photomask, the energy loss of the optical signal is performed according to a certain proportion each time. As shown in fig. 5, the light energy corresponding to the echo signal curve after passing through the photomask is attenuated, where the voltage value cannot be directly attenuated, but the light energy needs to be attenuated; thus, at each nominal distance, the corresponding light energy loss valueComprehensively analyzing the light energy loss value gamma obtained at each calibration distance to obtain the light energy loss gamma' of the photomask; for example, the respective light energy loss values Γ may be averaged, the mode is selected, the median is selected, and the like, and are not particularly limited herein. When only one calibration distance is selected, the calculated light energy loss value Γ under the calibration distance is directly used as the light energy loss Γ' of the light-transmitting mask.
Step 102, detecting actual light energy by using the laser radar after the photomask is mounted on the laser radar, and calculating calibrated light energy according to the actual light energy and the light energy loss of the photomask.
After the calibration of the light-transmitting cover is completed, the light-transmitting cover can be installed on the laser radar, and then the laser radar after the light-transmitting cover is installed is utilized for detection. Let the actual light energy detected by the laser radar be E' i The light energy loss of the light-transmitting mask identified in the step 101 is Γ', and the standard isThe calculation method of the fixed light energy Ei specifically comprises the following steps: ei=e' i /Γ'。
And step 103, determining the distance between the target and the laser radar according to the calibrated light energy.
Since a plurality of calibration distances and light energy E have been saved in said step 101 F The mapping relation between the target and the laser radar can be directly found according to the calibrated light energy, the calibrated distance corresponding to the calibrated light energy value can be determined, and the distance between the target and the laser radar can be further determined. The measured light energy is converted into the calibration light energy and then the distance is calculated, instead of directly calculating the distance according to the measured light energy, so that the influence of the light transmission cover is eliminated, and an actual correct distance value can be obtained.
In summary, in the method provided by the embodiment of the invention, before the laser radar is formally provided with the light-transmitting mask, one light intensity is preselected to calibrate the light-transmitting mask, and the energy change of the light signals before and after the light-transmitting mask is added is calculated to obtain the influence of the light-transmitting mask on the light intensity; when the laser radar is formally provided with the light-transmitting cover for use, the influence of the light-transmitting cover is utilized to carry out secondary algorithm calibration on the actually detected light signal energy, and the calibrated light signal energy is utilized to carry out distance calculation, so that the influence of the light-transmitting cover can be eliminated, and the ranging accuracy of the laser radar is improved.
Example 2
Based on the above embodiment 1, the embodiment of the present invention further provides the light energy E at each calibration distance in the step 101 F Light energy E B The calculation method of (1) is introduced. As can be seen from the equation (1) in embodiment 1, if the optical energy E is to be calculated, it is necessary to know the functional relation of the corresponding echo signal intensities and the echo signal flight time range. Thus, the light energy E F Light energy E B Referring to fig. 6, the following is a specific calculation procedure:
step 201, sampling the echo signal with the preset light intensity on a time axis, and performing curve fitting based on the sampled echo signal intensities to obtain a fitting function of the echo signal.
The receiving detector can be used for sampling to obtain a plurality of discrete echo signal intensities which are approximately parabolic, and then curve fitting is carried out based on the plurality of echo signal intensities, so that a fitting function of the echo signals can be obtained. Let the time corresponding to the maximum value of the echo signal intensity be t p To better calculate the light energy corresponding to a single pulse, the preferred fitting function of the present invention is as follows:
wherein V (t) represents the echo signal intensity, which changes with time; the coefficient a represents the height of the peak of the echo signal curve, namely the height of the echo signal intensity; the coefficient c represents the width of the echo signal curve in the lateral direction on the time axis. The equation (2) can better fit the change of the echo signal intensity, different coefficients represent the height and the transverse expansion amplitude of the echo signal intensity, and the specific fitting process can be realized by means of the existing mathematical model and is not described in detail herein. After the discrete echo signal intensity is obtained through high-speed sampling, although the bottom noise floods the starting point on the time axis, the fitting function of the echo signal can still be effectively reconstructed based on the sampling value above the signal threshold. It is particularly interesting here that the more sampled values of the echo signal strength, the denser the sampling interval, the more accurate the reconstructed fitting function, the more fitting to the actual values.
Step 202, determining the start time and the end time of the echo signal according to the echo signal curve. There are two methods by which it can be determined:
first, determining the starting time t of the echo signal according to two time intersections of the echo signal curve and the signal threshold 0 And end time t 1 . As described in connection with embodiment 1, to eliminate the bottom noise, a signal threshold is usually set, and a signal that actually exceeds the signal threshold is used as a testable reference. Referring to FIG. 4, since the echo signal curves are parabolic in shape, each echo signal curve has a signal thresholdTwo time points, so that the smaller time point of the two time points can be used as the starting time t of the echo signal 0 A larger time point is taken as the end time t of the echo signal 1 . For example, in fig. 5, when the optical signal does not pass through the mask (corresponding to curve 1), the start time corresponds to point a and the end time corresponds to point D of the echo signal; when the optical signal passes through the photomask (corresponding to curve 2), the starting time of the echo signal corresponds to point B, and the ending time corresponds to point C. With this method, the start time and the end time respectively determined for curve 1 and curve 2 are different.
As can be seen from fig. 5, the start-stop time obtained by the first method is not the actual start-stop time of the echo signal, but the actual start-stop time is points E and F in the figure, but is covered by the bottom noise, and cannot be directly obtained from the echo signal curve, but the time intersection point with the signal threshold can be directly obtained. Therefore, for convenient operation and calculation, the time intersection point with the signal threshold can be approximately used as the start-stop time to calculate, so that the same start-stop time acquisition method is adopted when the light energy calculation is carried out each time, and the consistency of the calculation process is ensured.
And secondly, carrying out reverse time deduction on the fitting function to enable the intensity of the echo signal to approach to zero value, and further calculating the starting time of the echo signal. Forward time deduction is carried out on the fitting function, so that the intensity of the echo signal approaches to zero, and the ending time of the echo signal is calculated; or the starting time is symmetrical by utilizing the symmetry axis of the echo signal curve, and the ending time of the echo signal is determined.
In theory, the value of V (t) in the formula (2) is not equal to zero, meaning that a zero value cannot be obtained by reverse calculation; therefore, the invention next proposes a calculation method for approximating a zero value, which is used for replacing an actual zero value, and further calculating to obtain a starting time, as follows: v (t) is less than or equal to epsilon. The selection of small epsilon is carried out by corresponding calculation in combination with the actual precision requirement, and the basic rule is as follows: the smaller the value of the small epsilon is chosen, the higher the time accuracy of the final calculated start time. For example, in fig. 5, when the optical signal does not pass through the mask (corresponding to curve 1), the start time corresponds to point E and the end time corresponds to point F of the echo signal; when the optical signal passes through the photomask (corresponding to curve 2), the starting time of the echo signal corresponds to point E, and the ending time corresponds to point F. It follows that the start time and the end time corresponding to the two curves are the same when the second method is adopted, and the start time and the end time corresponding to the two curves are true start-stop times, so that the calculation of the flight time is more accurate than that of the first method.
Step 203, calculating the corresponding light energy according to the fitting function, the starting time and the ending time of the echo signals.
With reference to FIG. 4, light energy E F Light energy E B The calculation formulas of (a) are respectively as follows:
wherein ,t0F and t1F Before the light signals with preset light intensity pass through the light transmission cover, the starting time and the ending time of the echo signals are corresponding; t is t 0B and t1B After the light signals with preset light intensity pass through the light transmission cover, the starting time and the ending time of the echo signals are corresponding; v (V) F (t) a fitting function of a corresponding echo signal before a light signal with preset light intensity passes through the light transmission cover; v (V) B And (t) is a fitting function of the corresponding echo signals after the light signals with preset light intensity pass through the light transmission cover. As shown in FIG. 5, the light intensity curve before passing through the mask is V F (t) the light intensity curve after passing through the mask decays to V B (t)。
Substituting formulas (3) and (4) into example 1The corresponding light energy loss value Γ at each calibration distance is specifically:
the above is the light energy E F Light energy E B In step 102, when the lidar performs actual detection, the corresponding actual light energy may also be calculated by referring to the above method, which is not described herein.
Example 3
Considering that lidar is used in a variety of environments, particularly in industrial applications, most are used in outdoor environments. The outdoor environment is abominable, the light-passing cover is after using a period, and the surface probably can cover the interference thing such as sleet dust for the light-passing cover further changes to the influence of light intensity. In this case, in order to ensure ranging accuracy, calibration correction may be periodically performed during the use of the lidar, so as to correct the light energy loss Γ 'of the light-transmitting mask, so as to complete calculation by using the new light energy loss Γ' later.
As shown in fig. 7, the calibration and correction process for the photomask is specifically as follows:
step 301, enabling the laser radar to emit a light signal with preset light intensity every preset period, and calculating the light energy E of the light signal with preset light intensity after passing through the light passing cover at any calibration distance B '。
Here, calibration correction may be performed once every preset period: as can be seen from embodiment 1, one or more calibration distances are selected when the light-transmitting mask is pre-calibrated, a calibration object is set at a distance d in front of the laser radar, and the laser radar is controlled to emit an optical signal with preset light intensity (consistent with the light intensity at the initial calibration) to the calibration object, so that the optical signal passes through the light-transmitting mask and then is transmitted to the calibration object. Then receiving and detecting the corresponding echo signals, and calculating the corresponding light energy E according to the echo signal curve B ' specific calculations are described in reference to example 2 and are not described hereinAnd (5) repeating the description.
Step 302, searching the mapping table according to the currently selected calibration distance, and determining the light energy E corresponding to the calibration distance F And based on the found light energy E F And light energy E B 'updating the light energy loss Γ' of the reticle.
A plurality of calibration distances and corresponding light energy E are stored in the mapping table F In order to ensure the accuracy of the updating result, the mapping relation between the two optical energy ratios under the same calibration distance is preferably selected to determine new optical energy loss. In step 301, the light energy E is detected again and calculated at the calibration distance d B ' it is therefore necessary here to find the light energy E corresponding to the calibration distance d from the mapping table F New light energy lossAfter the updating is completed, the latest Γ' can be used for completing the calculation when calculating the calibration light energy later.
Step 301 and step 302 are repeated once every preset period, and calibration correction is performed on the light-transmitting cover, so that influence of interference objects such as rain, snow, dust and the like on the light-transmitting cover can be fully considered, and the ranging accuracy of the laser radar is effectively improved.
Example 4
On the basis of the method for optimizing the influence of the laser radar light transmission mask provided in the foregoing embodiments 1-3, the present invention further provides a device for optimizing the influence of the laser radar light transmission mask, as shown in fig. 8, which is a schematic device architecture diagram of an embodiment of the present invention. The device for optimizing the effect of the laser radar photomask of the present embodiment includes one or more processors 21 and a memory 22. In fig. 8, a processor 21 is taken as an example.
The processor 21 and the memory 22 may be connected by a bus or otherwise, for example in fig. 8.
The memory 22 is used as a non-volatile computer readable storage medium for optimizing the effect of the laser radar mask, and can be used for storing non-volatile software programs, non-volatile computer executable programs and modules, such as the data analysis processing part in the method for optimizing the effect of the laser radar mask in embodiment 1. The processor 21 executes various functional applications of the apparatus for optimizing a lidar reticle influence and data processing, that is, a data analysis processing section in the method for optimizing a lidar reticle influence of embodiment 1 to embodiment 3, by executing nonvolatile software programs, instructions, and modules stored in the memory 22.
The memory 22 may include high-speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, the memory 22 may optionally include memory located remotely from the processor 21, such remote memory being connectable to the processor 21 through a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.
The program instructions/modules are stored in the memory 22, and when executed by the one or more processors 21, perform the method of optimizing the effect of a lidar reticle in embodiment 1 described above, for example, perform the data analysis processing portions in the respective steps shown in fig. 3, 6, and 7 described above.
Those of ordinary skill in the art will appreciate that all or a portion of the steps in the various methods of the embodiments may be implemented by a program that instructs associated hardware, the program may be stored on a computer readable storage medium, the storage medium may include: read Only Memory (ROM), random access Memory (RAM, random Access Memory), magnetic or optical disk, and the like.
It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the invention and is not intended to limit the invention, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (5)
1. A method of optimizing the effect of a lidar reticle, comprising:
selecting one or more calibration distances, and calculating the light energy of the light signal with preset light intensity before passing through the photomask under each calibration distanceE F And light energy after passing through the light-transmitting maskE B And storing each calibration distance and corresponding light energy by using a mapping tableE F Mapping relation between the two;
using corresponding light energy at each calibration distanceE F And light energyE B Calculating corresponding light energy loss valueFurther determining the light energy loss of the light-transmitting mask>'；
Sampling the echo signals with preset light intensity on a time axis, and performing curve fitting based on the intensities of the echo signals obtained by sampling to obtain a fitting function of the echo signals;
determining the starting time and the ending time of the echo signal according to the echo signal curve;
according to the fitting function, the starting time and the ending time of the echo signals, the corresponding light energy is calculatedE F Light energyE B ；
Detecting actual light energy by the laser radar after the photomask is mounted on the laser radar, and according to the actual light energy and the light energy loss of the photomask' calculating a nominal light energy;
determining the distance between a target and the laser radar according to the calibrated light energy;
the fitting function of the echo signals is specifically as follows:
wherein ,V(t)representing the intensity of the echo signal, which changes with time; coefficients ofaRepresenting the height of the peak of the echo signal curve; coefficients ofcRepresenting the transverse expansion width of the echo signal curve on the time axis;t p representing the time corresponding to the maximum value of the echo signal intensity on the echo signal curve;
the method for determining the starting time and the ending time of the echo signal according to the echo signal curve comprises the following steps:
performing reverse time deduction on the fitting function to enable the intensity of the echo signal to approach to zero value, and further calculating the initial time of the echo signal;
forward time deduction is carried out on the fitting function, so that the intensity of the echo signal approaches to zero, and the ending time of the echo signal is calculated; or the starting time is symmetrical by utilizing the symmetry axis of the echo signal curve, and the ending time of the echo signal is determined.
2. The method for optimizing the effect of a laser radar photomask according to claim 1, wherein the determining the distance between the target and the laser radar according to the calibration light energy is specifically:
and searching the mapping table according to the calibrated light energy, determining a calibrated distance corresponding to the calibrated light energy value, and further determining the distance between the target and the laser radar.
3. The method of optimizing the effect of a lidar reticle of claim 1, wherein the corresponding optical energy loss value at each calibration distanceThe calculation method of (a) specifically comprises the following steps:
；
E B =；
E F =；
wherein ,t 0F andt 1F before the light signals with preset light intensity pass through the light transmission cover, the starting time and the ending time of the echo signals are corresponding;t 0B andt 1B after the light signals with preset light intensity pass through the light transmission cover, the starting time and the ending time of the echo signals are corresponding;V F (t)before a light signal with preset light intensity passes through the light transmission cover, a fitting function of the echo signal is corresponding;V B (t)and after the light signal with preset light intensity passes through the light transmission cover, the fitting function of the echo signal is corresponding.
4. The method of optimizing the effect of a lidar reticle of claim 1, the method further comprising:
the laser radar emits light signals with preset light intensity every preset period, and the light energy after the light signals with preset light intensity pass through the light passing cover is calculated at any calibration distanceE B '；
Searching the mapping table according to the currently selected calibration distance, and determining the light energy corresponding to the calibration distanceE F And based on the light energy foundE F And light energyE B ' update the optical energy loss of the reticle'。
5. An apparatus for optimizing the effect of a lidar reticle comprising at least one processor and a memory, the at least one processor and the memory being coupled via a data bus, the memory storing instructions executable by the at least one processor, the instructions, when executed by the processor, for performing the method for optimizing the effect of a lidar reticle of any of claims 1-4.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109346841A (en) * | 2018-09-29 | 2019-02-15 | 芜湖易来达雷达科技有限公司 | The production method of radome making material identification method, radome and radome |
| CN110849501A (en) * | 2019-10-30 | 2020-02-28 | 许昌许继软件技术有限公司 | Method for measuring and calibrating optical switch loss in distributed optical fiber temperature measuring device |
| CN111551946A (en) * | 2020-04-30 | 2020-08-18 | 深圳煜炜光学科技有限公司 | Laser radar and light-transmitting cover dirt detection method |
| CN111722205A (en) * | 2019-03-22 | 2020-09-29 | 深圳市速腾聚创科技有限公司 | Calibration method, system, device, equipment and storage medium for laser ranging |
| CN112363149A (en) * | 2020-11-06 | 2021-02-12 | 深圳奥锐达科技有限公司 | Ranging error calibration system and calibration method for laser radar |
| CN212848823U (en) * | 2020-09-10 | 2021-03-30 | 纵目科技（上海）股份有限公司 | Antenna housing for radar sensor and radar sensor |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102009001239A1 (en) * | 2009-02-27 | 2010-09-02 | Robert Bosch Gmbh | Method for detecting sensitivity losses of an FMCW radar detector by diffuse loss sources |
-
2021
- 2021-04-30 CN CN202110489009.3A patent/CN113219442B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109346841A (en) * | 2018-09-29 | 2019-02-15 | 芜湖易来达雷达科技有限公司 | The production method of radome making material identification method, radome and radome |
| CN111722205A (en) * | 2019-03-22 | 2020-09-29 | 深圳市速腾聚创科技有限公司 | Calibration method, system, device, equipment and storage medium for laser ranging |
| CN110849501A (en) * | 2019-10-30 | 2020-02-28 | 许昌许继软件技术有限公司 | Method for measuring and calibrating optical switch loss in distributed optical fiber temperature measuring device |
| CN111551946A (en) * | 2020-04-30 | 2020-08-18 | 深圳煜炜光学科技有限公司 | Laser radar and light-transmitting cover dirt detection method |
| CN212848823U (en) * | 2020-09-10 | 2021-03-30 | 纵目科技（上海）股份有限公司 | Antenna housing for radar sensor and radar sensor |
| CN112363149A (en) * | 2020-11-06 | 2021-02-12 | 深圳奥锐达科技有限公司 | Ranging error calibration system and calibration method for laser radar |
Non-Patent Citations (2)
| Title |
|---|
| 杜松 等.激光雷达回波强度数据辐射特性分析.《中国科学院大学学报》.2019,第392-400页. * |
| 陈辉 秦顺友.毫米波动中通天线罩传输损耗测量及误差分析.《微波学报》.2015,第171-173页. * |
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