CN111551946B - Laser radar and light-transmitting cover dirt detection method - Google Patents

Abstract

The invention discloses a laser radar and a method for detecting contamination of a light-passing cover. The laser radar comprises a laser transmitting unit, a laser receiving unit, a processing unit and a light-passing cover. The processing unit is connected with the laser receiving unit; the laser transmitting unit is used for The laser signal is emitted; the laser receiving unit is used to receive the laser signal reflected by the light-passing cover and the laser signal reflected by the measured object; in the initial setting state, the processing unit is used for according to the reflection intensity of the laser signal reflected by the light-passing cover Set the alarm threshold; in the working state, the processing unit is further configured to determine the contamination of the light cover according to the relationship between the reflection intensity of the laser signal reflected by the light cover and the alarm threshold. The invention adopts the measuring laser of the laser radar as the light source for detecting the contamination of the hood, and the laser receiving unit of the lidar serves as the receiving device for the dirty reflected light of the hood, which can well detect whether each measurement angle is dirty.

Description

A detection method for the contamination of lidar and light mask

technical field

The invention belongs to the field of lasers, and more particularly, relates to a method for detecting contamination of a laser radar and a light-passing mask.

Background technique

Common lidars are composed of laser transmitters, laser receivers, and light-passing covers. The light-passing cover is an indispensable part of the laser emission and receiving path. It has internal optical and circuit components to protect the laser radar and isolate stray light. and so on.

As a non-contact measuring device, the cleanliness of the lidar directly affects the range and measurement accuracy of the lidar. How to detect whether there is pollution on the surface of the lidar is an indispensable part of the use and maintenance of lidar.

As shown in FIG. 1 , in the existing solution, an additional detection light source generator 11 and a detection light source receiver 13 are used to measure whether the light-passing cover 12 is dirty. This solution requires the detection light source generator 11 to emit a beam of laser light through Through the light-passing cover 12, the detection light source receiver 13 receives the light on the other side of the light-passing cover 12, and judges whether there is dirt on the light-passing cover 12 according to the received light intensity. When the size of the light cover or the available angle range is large, multiple sets of such detection light source generators 11 and detection light source receivers 13 need to be used, and the light cover 12 also needs to have a certain inclination in the vertical direction for normal installation and use. . The scanning lidar has a wide detection range, and the horizontal detection angle range covers 180-360 degrees. If it is necessary to accurately determine the location of the contamination of the optical mask, it is necessary to place dense detection devices.

In view of this, overcoming the deficiencies of the prior art products is an urgent problem to be solved in the technical field.

SUMMARY OF THE INVENTION

In view of the above defects or improvement requirements of the prior art, the present invention provides a laser radar and a method for detecting the contamination of a light-passing cover. The laser receiving unit is used as a receiving device for the dirty reflected light of the hood, which can well detect whether each measurement angle is dirty.

In order to achieve the above object, according to an aspect of the present invention, a laser radar is provided. The laser radar includes a laser transmitting unit 21, a laser receiving unit 22, a processing unit 23 and a light-passing cover 24. The processing unit 23 is connected to the the laser receiving unit 22 is connected;

The laser emitting unit 21 is used for emitting laser signals;

The laser receiving unit 22 is used to receive the laser signal reflected by the light-passing cover 24 and the laser signal reflected by the measured object;

In the initial setting state, the processing unit 23 is configured to set an alarm threshold according to the reflection intensity of the laser signal reflected by the light-passing cover 24;

In the working state, the processing unit 23 is further configured to determine the contamination of the light-passing cover 24 according to the magnitude relationship between the reflection intensity of the laser signal reflected by the light-passing cover 24 and the alarm threshold .

In order to achieve the above object, according to one aspect of the present invention, a method for detecting contamination of a light-passing cover is provided. The detection method is applied to a laser radar, and the laser radar includes a laser transmitting unit, a laser receiving unit and a light-passing cover. , the laser emitting unit is used for emitting laser signal; the laser receiving unit is used for receiving the laser signal reflected by the light-passing cover and the laser signal reflected by the measured object;

The detection method includes:

In the initial setting state, set the alarm threshold according to the reflection intensity of the laser signal reflected by the light-passing cover;

In the working state, monitoring the first laser signal reflected by the light-passing cover;

According to the magnitude relationship between the reflection intensity of the first laser signal and the alarm threshold, the contamination of the light-passing cover is determined.

Preferably, the alarm threshold includes a first alarm threshold and a second alarm threshold, wherein the first alarm threshold is smaller than the second alarm threshold;

The determining, according to the magnitude relationship between the reflection intensity of the first laser signal and the alarm threshold, the contamination of the light-passing cover includes:

judging whether the reflection intensity of the first laser signal is greater than the second alarm threshold;

If the reflection intensity of the first laser signal is greater than the second alarm threshold, a serious alarm signal is generated to remind the user that the contamination of the light-passing cover has affected normal operation.

Preferably, the detection method further includes:

If the reflection intensity of the first laser signal is not greater than the second alarm threshold, determine whether the reflection intensity of the first laser signal is greater than the first alarm threshold;

If the reflection intensity of the first laser signal is greater than the first alarm threshold, a general alarm signal is generated to remind the user that the light-passing cover needs to be cleaned, so as not to affect the normal operation of the laser radar.

Preferably, the detection method further includes:

In the initial setting state, obtain the time interval T0 between the laser emission signal and the laser reflection signal of the mask;

The monitoring of the first laser signal reflected by the light pass cover includes:

After the laser emitting unit emits a laser signal;

The laser signal acquired within the time interval T0 is demarcated as the first laser signal reflected by the light-passing cover.

Preferably, when the lidar is in a working state, the light-passing cover is relatively stationary, and the laser emitting unit and the laser-receiving unit move relative to the light-passing cover;

The detection method also includes:

If the dirty condition of the light shield has affected normal work, demarcate the dirty area on the light shield;

acquiring the positional relationship of the laser emitting unit relative to the dirty area;

When the laser emission signal is close to the edge of the dirty area, increasing the movement speed of the laser emission unit, so that the laser emission signal avoids the dirty area;

After the laser emission signal crosses the dirty area, the movement speed of the laser emission unit is restored to measure the measured object.

Preferably, the detection method further includes:

If the dirty condition of the light shield has affected normal work, demarcate the dirty area on the light shield;

acquiring a second laser signal reflected by the measured object passing through the dirty area;

Compensation is performed on the second laser signal to eliminate the influence of the dirty area on the measured object.

Preferably, the compensation for the second laser signal includes:

When the laser emitting unit enters the boundary of the dirty area, acquire a third laser signal reflected by the measured object;

When the laser emitting unit leaves the boundary of the dirty area, acquire a fourth laser signal reflected by the measured object;

formulating a compensation strategy based on the third laser signal and the fourth laser signal;

The second laser signal is compensated according to the compensation strategy.

Preferably, the formulating a compensation strategy based on the third laser signal and the fourth laser signal includes:

judging whether the difference between the third laser signal and the fourth laser signal is less than a preset difference threshold;

If the difference between the third laser signal and the fourth laser signal is less than a preset difference threshold, acquiring a first reference difference between the second laser signal and the third laser signal, respectively, and , the second reference difference between the second laser signal and the fourth laser signal;

A compensation strategy is obtained by averaging the first reference difference and the second reference difference.

Preferably, the formulating a compensation strategy based on the third laser signal and the fourth laser signal includes:

If the difference between the third laser signal and the fourth laser signal is not less than a preset difference threshold, dividing the dirty area into at least two sub-areas;

respectively assigning weights to the first reference difference and the second reference difference according to the dirt condition of the sub-region;

A compensation strategy is obtained by performing a weighted average according to the first reference difference, the second reference difference, and their assigned weight values.

In general, compared with the prior art, the above technical solutions conceived by the present invention have the following beneficial effects: the present invention provides a laser radar and a method for detecting contamination of a light-passing mask, the laser radar includes a laser emitting unit, a laser A receiving unit, a processing unit and a light-passing cover, the processing unit is connected with the laser receiving unit; the laser-emitting unit is used for transmitting laser signals; the laser-receiving unit is used for receiving the laser signal reflected by the light-passing cover and the laser signal reflected by the measured object ; In the initial setting state, the processing unit is used to set the alarm threshold according to the reflection intensity of the laser signal reflected by the light-passing cover; in the working state, the processing unit is also used for the reflection intensity of the laser signal reflected by the light-passing cover. The magnitude relationship between the alarm thresholds determines the contamination of the light shield.

The invention adopts the measuring laser of the laser radar as the light source for detecting the contamination of the light-passing cover, and the laser receiving unit of the laser radar is used as the receiving device for the dirty reflected light of the light-passing cover, which can well detect whether there is contamination at each measurement angle, And no additional cost is required, and there are no requirements for the geometry of the optical mask.

Description of drawings

1 is a schematic structural diagram of a laser radar in the prior art;

FIG. 2 is a schematic structural diagram of a laser radar according to an embodiment of the present invention;

3 is a schematic structural diagram of another laser radar provided by an embodiment of the present invention;

4 is a schematic diagram of a curve between the reflection intensity of a laser emission signal and the reflection intensity of a light-passing mask reflection signal provided by an embodiment of the present invention;

5 is a schematic diagram of curves of the reflection intensity of a laser emission signal, the reflection intensity of a light-passing mask reflection signal, and the reflection intensity of a measured object reflection signal provided by an embodiment of the present invention;

6 is a schematic flowchart of a method for detecting contamination of a light-passing cover provided by an embodiment of the present invention;

7 is a schematic flowchart of another method for detecting contamination of a light-passing mask provided by an embodiment of the present invention;

FIG. 8 is a schematic flowchart of another method for detecting contamination of a light pass mask provided by an embodiment of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

In the description of the present invention, the orientation or positional relationship indicated by the terms "inner", "outer", "longitudinal", "lateral", "upper", "lower", "top", "bottom", etc. are based on the drawings The orientation or positional relationship shown is only for the convenience of describing the present invention rather than requiring the present invention to be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

Example 1:

Referring to FIG. 2 , the present invention provides a laser radar, which includes a laser transmitting unit 21 , a laser receiving unit 22 , a processing unit 23 and a light-passing cover 24 , and the processing unit 23 is connected to the laser receiving unit 22 .

In actual use, the laser transmitting unit 21 is used to transmit laser signals; the laser receiving unit 22 is used to receive the laser signals reflected by the light-passing cover 24 and the laser signals reflected by the object to be measured (not marked). .

In the initial setting state, the processing unit 23 is configured to set an alarm threshold according to the reflection intensity of the laser signal reflected by the light-passing cover 24, wherein, in the initial setting state, the surface of the light-passing cover 24 is clean; In the working state, the processing unit 23 is further configured to determine the contamination of the light-passing cover 24 according to the magnitude relationship between the reflection intensity of the laser signal reflected by the light-passing cover 24 and the alarm threshold . The processing unit 23 is also used to determine the contour of the measured object according to the relationship between the laser emission signal and the laser reflection signal reflected by the measured object, and can also determine the distance between the laser radar and the measured object.

Since the surface of the light-passing cover 24 cannot be absolutely smooth, the light-passing cover 24 itself will have diffuse reflection. When the outer surface of the light-passing cover 24 is polluted, the reflection of the light-passing cover 24 itself will increase. The stronger it is, therefore, it can be judged whether the light-transmitting cover 24 is contaminated by detecting the reflection intensity of the light-passing cover 24 itself.

Continuing to refer to FIG. 3 , the lidar further includes a waveform extraction unit 25, which is connected to the laser receiving unit 22. The waveform extraction unit 25 is used to extract the laser signal reflected by the light-passing cover 24, and the The laser signal reflected by the measured object.

The lidar further includes an analog-to-digital converter 26, the analog-to-digital converter 26 is connected to the waveform extraction unit 25, and the analog-to-digital converter 26 is used for converting an analog signal into a digital signal. The processing unit 23 is also connected to the analog-to-digital converter 26, and the laser signal reflected by the measured object is sent to the processing unit 23 for data processing after analog-to-digital conversion.

The lidar further includes a comparator 27, the comparator 27 is connected to the analog-to-digital converter 26, and the comparator 27 is used to compare the reflection intensity of the first laser signal with the warning threshold, To determine the contamination of the clear mask 24 .

Since the laser receiving device will not only receive the laser light reflected by the object to be measured, but also receive the laser light reflected by the light-passing cover 24, in order to distinguish the above two signals, the laser radar also includes a timer 28, the timer 28 is used for timing, specifically, in the initial setting state, to obtain the time interval T0 between the laser emission signal and the laser reflection signal of the light-passing cover 24, after the laser emission unit 21 emits the laser signal; The laser signal acquired within the time interval T0 is demarcated as the first laser signal reflected by the light-passing cover 24 . In actual use, the timing duration of the timer 28 is set to T0.

The following describes the setting method of the alarm threshold in detail with reference to FIG. 4 and FIG. 5: As shown in FIG. 4, the curve S1 is the signal emitted by the laser emitting unit 21, the curve S2 is the laser signal reflected by the clean light-passing cover 24, and T0 represents the laser The time interval between the emission signal and the laser reflection signal of the light-passing cover 24 , wherein the start time of T0 may correspond to the time point when the laser emitting unit 21 emits stably, and the end time of T0 may correspond to the reflected light of the light-passing cover 24 The point in time when the intensity is close to zero. It can be understood that the time T0 represents the position of the reflection signal of the light-passing cover 24 on the time axis, because in the actual measurement, the reflection signal of the measured object and the reflection signal of the light-passing cover 24 are arranged on the time axis, and T0 is used for Mark the location of the light shield 24.

4 and 5 , V0 is the peak value of the laser signal reflected by the clean hood 24 , V2 is the average value of the laser reflected by the measured object, and V1=V0+(V2-V0)/2.

In this embodiment, the alarm threshold includes a first alarm threshold and a second alarm threshold, wherein the first alarm threshold is smaller than the second alarm threshold. With reference to FIG. 4 and FIG. 5 , the first alarm threshold may be set to V1, and the second alarm threshold may be set to V1. The threshold value is V2, wherein the specific values of the first alarm threshold and the second alarm threshold may be determined according to actual conditions, which are not specifically limited here.

Specifically, the lidar determines whether the reflection intensity of the first laser signal is greater than the second alarm threshold; if the reflection intensity of the first laser signal is greater than the second alarm threshold, a serious alarm signal is generated , to remind the user that the contamination of the light-passing cover 24 has affected the normal operation and needs to be cleaned immediately, otherwise the laser signal reflected by the object under test received by the lidar is invalid. If the reflection intensity of the first laser signal is not greater than the second alarm threshold, determine whether the reflection intensity of the first laser signal is greater than the first alarm threshold; the reflection intensity of the first laser signal is greater than the first alarm threshold If the first alarm threshold is exceeded, a general alarm signal is generated to remind the user that the light-transmitting cover 24 needs to be cleaned, so as not to affect the normal operation of the lidar.

That is, within the time T0, the waveform extraction unit 25 is used to extract the reflection signal of the light-passing cover 24, and the reflection intensity of the light-passing cover 24 is monitored. When the reflection intensity is greater than V1 and less than V2, a general alarm signal is generated to remind the user to pass the light. Cover 24 is dirty and needs to be cleaned. Although an alarm is generated at this time, the normal operation of the lidar has not been affected because the reflection intensity of the light-passing cover 24 is less than V2. When the reflection intensity of the light-passing cover 24 is greater than V2, the contamination of the light-passing cover 24 has affected the normal operation, and a serious alarm signal is generated, prompting the user that the light-passing cover 24 needs to be cleaned immediately.

In a preferred embodiment, before generating a serious alarm signal or a general alarm signal, the angular range of the dirty area is acquired, and when the angular range of the dirty area exceeds a preset angular range, a corresponding alarm signal is generated to avoid frequent alarms Affect the customer experience.

In addition, the reflection intensity of the reflected signal from the light-passing cover 24 is not limited to the voltage value of the reflected signal, but may also be the width of the signal or the area of the signal.

In this embodiment, when the laser radar is working normally, the emitted laser signal passes through the light-passing cover 24, and the measured object is reflected on the illuminated object. After the laser radar receives the reflected signal of the measured object, it emits The signal and the reflected signal determine the measured object information, for example, the distance between the measured object and the lidar is calculated from the time difference between the transmitted signal and the reflected signal.

Example 2:

In combination with Embodiment 1, this embodiment provides a method for detecting contamination of a light-passing cover. The detection method is applied to the lidar of Embodiment 1. The laser radar includes a laser transmitting unit, a laser receiving unit, and a light-passing cover. , the laser emitting unit is used for emitting a laser signal; the laser receiving unit is used for receiving the laser signal reflected by the light-passing cover and the laser signal reflected by the measured object.

Referring to Figure 6, the detection method includes the following steps:

Step 101 : in an initial setting state, set an alarm threshold according to the reflection intensity of the laser signal reflected by the light-passing cover.

Wherein, in the initial setting state, the surface of the light shield is clean.

Wherein, the reflection intensity of the reflected signal of the light-passing mask is not limited to the voltage value of the reflected signal, but may also be the width of the signal or the area of the signal.

The alarm threshold includes a first alarm threshold and a second alarm threshold, wherein the first alarm threshold is smaller than the second alarm threshold.

The method for setting the first alarm threshold and the second alarm threshold may refer to Embodiment 1, and details are not described herein again.

Step 102 : in the working state, monitor the first laser signal reflected by the light-passing cover.

Wherein, the laser receiving unit receives the first laser signal reflected by the light-passing cover in real time, and the first one here is for the convenience of distinguishing different laser signals, and has no special meaning.

In the initial setting state, firstly, the time interval T0 between the laser emission signal and the laser reflection signal of the light-passing cover is obtained; the laser signal obtained within the time interval T0 is calibrated to be reflected by the light-passing cover the first laser signal.

Step 103: According to the magnitude relationship between the reflection intensity of the first laser signal and the alarm threshold, determine the contamination of the light-passing cover.

Specifically, it is judged whether the reflection intensity of the first laser signal is greater than the second alarm threshold; if the reflection intensity of the first laser signal is greater than the second alarm threshold, a serious alarm signal is generated to remind the user of the The contamination of the above-mentioned light shield has affected the normal operation.

If the reflection intensity of the first laser signal is not greater than the second alarm threshold, determine whether the reflection intensity of the first laser signal is greater than the first alarm threshold; if the reflection intensity of the first laser signal is greater than the first alarm threshold When the first alarm threshold is set, a general alarm signal is generated to remind the user that the light-passing cover needs to be cleaned, so as not to affect the normal operation of the laser radar.

In a preferred embodiment, before generating a serious alarm signal or a general alarm signal, the angular range of the dirty area is obtained, and when the angular range of the dirty area exceeds the preset angular range, a corresponding alarm signal is generated to avoid frequent alarms Affect the customer experience.

In this embodiment, the measurement laser of the lidar is used as the light source for detecting the contamination of the hood, and the laser receiving unit of the lidar is used as the receiving device for the dirty reflected light of the hood, which can well detect whether each measurement angle is dirty. , and no additional cost is required, and there are no requirements for the geometry of the optical mask.

Example 3:

In a practical application scenario, when the optical cover is in a dirty state, it cannot be cleaned in time. In order to ensure that the information of the measured object can be obtained normally, in an optional embodiment, the laser emitting unit can be avoided as much as possible. dirty area, so as to obtain the information of the measured object more realistically.

In a specific application scenario, when the lidar is in a working state, the light-passing cover is relatively stationary, and the laser emitting unit and the laser-receiving unit move relative to the light-passing cover. Referring to FIG. 7 , for the lidar of the foregoing manner, in an optional embodiment, the detection method includes the following steps:

Step 201 : in an initial setting state, set an alarm threshold according to the reflection intensity of the laser signal reflected by the light-passing cover.

Wherein, in the initial setting state, the surface of the light shield is clean.

Wherein, the reflection intensity of the reflected signal of the light-passing mask is not limited to the voltage value of the reflected signal, but may also be the width of the signal or the area of the signal.

The alarm threshold includes a first alarm threshold and a second alarm threshold, wherein the first alarm threshold is smaller than the second alarm threshold.

The method for setting the first alarm threshold and the second alarm threshold may refer to Embodiment 1, and details are not described herein again.

Step 202 : in the working state, monitor the first laser signal reflected by the light-passing cover.

Wherein, the laser receiving unit receives the first laser signal reflected by the light-passing cover in real time, and the first one here is for the convenience of distinguishing different laser signals, and has no special meaning.

In the initial setting state, firstly, the time interval T0 between the laser emission signal and the laser reflection signal of the light-passing cover is obtained; the laser signal obtained within the time interval T0 is calibrated to be reflected by the light-passing cover the first laser signal.

Step 203 : According to the magnitude relationship between the reflection intensity of the first laser signal and the alarm threshold, determine the contamination of the light-passing cover.

Specifically, it is judged whether the reflection intensity of the first laser signal is greater than the second alarm threshold; if the reflection intensity of the first laser signal is greater than the second alarm threshold, a serious alarm signal is generated to remind the user of the The contamination of the above-mentioned light shield has affected the normal operation.

If the reflection intensity of the first laser signal is not greater than the second alarm threshold, determine whether the reflection intensity of the first laser signal is greater than the first alarm threshold; if the reflection intensity of the first laser signal is greater than the first alarm threshold When the first alarm threshold is set, a general alarm signal is generated to remind the user that the light-passing cover needs to be cleaned, so as not to affect the normal operation of the laser radar.

In a preferred embodiment, before generating a serious alarm signal or a general alarm signal, the angular range of the dirty area is acquired, and when the angular range of the dirty area exceeds a preset angular range, a corresponding alarm signal is generated to avoid frequent alarms Affect the customer experience.

Step 204 : If the dirty condition of the light-passing cover has affected the normal operation, the dirty area on the light-passing cover is calibrated.

Step 205: Obtain the positional relationship of the laser emitting unit relative to the dirty area.

The positional relationship of the laser emitting unit relative to the dirty area can be calibrated by means of coordinates, and the specific position coordinates of the laser emitting unit can be acquired in real time, so as to avoid the following steps 206 to 207 Dirty area.

Step 206: When the laser emission signal approaches the edge of the dirty area, increase the movement speed of the laser emission unit, so that the laser emission signal avoids the dirty area.

Wherein, the laser receiving unit can move synchronously with the laser emitting unit.

Step 207: After the laser emission signal crosses the dirty area, restore the movement speed of the laser emission unit to measure the object to be measured.

In this embodiment, the measurement laser of the lidar is used as the light source for detecting the contamination of the hood, and the laser receiving unit of the lidar is used as the receiving device for the dirty reflected light of the hood, which can well detect whether each measurement angle is dirty. , and no additional cost is required, and there are no requirements for the geometry of the optical mask.

Moreover, by adjusting the rotation speed of the laser emitting unit relative to the light-passing cover, the dirty area can be avoided as much as possible, so that the information of the measured object can be obtained more accurately.

In another optional embodiment, the laser reflection signal can be compensated, so as to obtain the information of the measured object more realistically. As shown in FIG. 8 , the detection method includes the following steps:

Step 301: In the initial setting state, set an alarm threshold according to the reflection intensity of the laser signal reflected by the light-passing cover.

Step 302 : in the working state, monitor the first laser signal reflected by the light-passing cover.

Step 303: According to the magnitude relationship between the reflection intensity of the first laser signal and the alarm threshold, determine the contamination of the light-passing cover.

For the specific process of steps 301 to 303, please refer to Embodiment 1, which will not be repeated here.

Step 304 : If the contamination of the light-transmitting cover has affected the normal operation, calibrate the dirty area on the light-passing cover.

Step 305: Acquire a second laser signal reflected by the measured object passing through the dirty area.

Wherein, the second laser signal is the signal reflected by the measured object, and the signal passes through the dirty area. When the dirty area is large, the second laser signal may be multiple, that is, every time the laser emitting unit is adjusted At one position, the laser emission signal will pass through a certain point in the dirty area, and the corresponding second laser signal will also pass through a certain point in the dirty area.

Step 306: Compensate the second laser signal to eliminate the influence of the dirty area on the measured object.

In an optional embodiment, in step 306, the compensating the second laser signal includes: when the laser emitting unit enters the boundary of the dirty area, that is, when the laser emitting unit is detected When entering the dirty region from the non-dirty region, acquire the third laser signal reflected by the measured object; when the laser emitting unit leaves the boundary of the dirty region, that is, when it is detected that the laser emitting unit has When the dirty area enters the non-dirty area, the fourth laser signal reflected by the measured object is acquired, and a compensation strategy is formulated based on the third laser signal and the fourth laser signal.

Among them, the aforementioned second, third and fourth are for the convenience of distinguishing different laser signals, and have no special meaning.

In an optional embodiment, it is determined whether the difference between the third laser signal and the fourth laser signal is less than a preset difference threshold; if the difference between the third laser signal and the fourth laser signal is The difference is less than a preset difference threshold, then respectively obtain the first reference difference between the second laser signal and the third laser signal, and the difference between the second laser signal and the fourth laser signal The second benchmark difference of , and the average value of the first benchmark difference and the second benchmark difference is obtained to obtain a compensation strategy.

In another optional embodiment, if the difference between the third laser signal and the fourth laser signal is not less than a preset difference threshold, dividing the dirty area into at least two sub-areas; The first reference difference and the second reference difference are respectively assigned weights according to the contamination of the sub-regions; according to the first reference difference, the second reference difference and the assigned weight Weighted average to get compensation strategy. The second laser signal is compensated according to the compensation strategy.

In this embodiment, the measuring laser of the lidar is used as the light source for detecting the contamination of the hood, and the laser receiving unit of the lidar is used as the receiving device for the dirty reflected light of the hood, which can well detect whether each measurement angle is dirty. , and no additional cost is required, and there are no requirements for the geometry of the optical mask.

Moreover, a compensation strategy can be specified according to the relationship between the reflected signals passing through the dirty area to compensate the laser signal, so as to obtain the information of the measured object more accurately.

Those skilled in the art can easily understand that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, etc., All should be included within the protection scope of the present invention.

Claims (6)

1. A detection method for contamination of a light-passing cover is characterized in that, the detection method is applied to a laser radar, and the laser radar comprises a laser emission unit, a laser receiving unit and a light-passing cover, and the laser emission unit is used for emit laser signal; the laser receiving unit is used for receiving the laser signal reflected by the light-passing cover and the laser signal reflected by the measured object; The detection method includes: In the initial setting state, set the alarm threshold according to the reflection intensity of the laser signal reflected by the light-passing cover; In the working state, monitoring the first laser signal reflected by the light-passing cover; According to the magnitude relationship between the reflection intensity of the first laser signal and the alarm threshold, determine the contamination of the light-passing cover; If the dirty condition of the light shield has affected normal work, demarcate the dirty area on the light shield; acquiring a second laser signal reflected by the measured object passing through the dirty area; Compensating the second laser signal to eliminate the influence of the dirty area on the measured object; wherein the compensating the second laser signal includes: when the laser emitting unit enters the When the boundary of the dirty area is detected, the third laser signal reflected by the measured object is acquired; when the laser emitting unit leaves the boundary of the dirty area, the fourth laser signal reflected by the detected object is acquired formulating a compensation strategy based on the third laser signal and the fourth laser signal; compensating the second laser signal according to the compensation strategy; The formulating a compensation strategy based on the third laser signal and the fourth laser signal includes: judging whether the difference between the third laser signal and the fourth laser signal is less than a preset difference threshold; if If the difference between the third laser signal and the fourth laser signal is less than a preset difference threshold, then respectively obtain the first reference difference between the second laser signal and the third laser signal, and, a second reference difference between the second laser signal and the fourth laser signal; and taking an average of the first reference difference and the second reference difference to obtain a compensation strategy. 2. The detection method according to claim 1, wherein the alarm threshold comprises a first alarm threshold and a second alarm threshold, wherein the first alarm threshold is smaller than the second alarm threshold; The determining, according to the magnitude relationship between the reflection intensity of the first laser signal and the alarm threshold, the contamination of the light-passing cover includes: judging whether the reflection intensity of the first laser signal is greater than the second alarm threshold; If the reflection intensity of the first laser signal is greater than the second alarm threshold, a serious alarm signal is generated to remind the user that the contamination of the light-passing cover has affected normal operation. 3. The detection method according to claim 2, wherein the detection method further comprises: If the reflection intensity of the first laser signal is not greater than the second alarm threshold, determine whether the reflection intensity of the first laser signal is greater than the first alarm threshold; If the reflection intensity of the first laser signal is greater than the first alarm threshold, a general alarm signal is generated to remind the user that the light-passing cover needs to be cleaned, so as not to affect the normal operation of the laser radar. 4. The detection method according to claim 1, wherein the detection method further comprises: In the initial setting state, obtain the time interval T0 between the laser emission signal and the laser reflection signal of the mask; The monitoring of the first laser signal reflected by the light pass cover includes: After the laser emitting unit emits a laser signal; The laser signal acquired within the time interval T0 is demarcated as the first laser signal reflected by the light-passing cover. 5 . The detection method according to claim 1 , wherein when the lidar is in a working state, the light-passing cover is relatively stationary, and the laser emitting unit and the laser receiving unit are relatively stationary. 6 . Describe the movement of the light mask; The detection method also includes: If the dirty condition of the light shield has affected normal work, demarcate the dirty area on the light shield; acquiring the positional relationship of the laser emitting unit relative to the dirty area; When the laser emission signal is close to the edge of the dirty area, increasing the movement speed of the laser emission unit, so that the laser emission signal avoids the dirty area; After the laser emission signal crosses the dirty area, the movement speed of the laser emission unit is restored to measure the measured object. 6. The detection method according to claim 1, wherein the formulating a compensation strategy based on the third laser signal and the fourth laser signal comprises: If the difference between the third laser signal and the fourth laser signal is not less than a preset difference threshold, dividing the dirty area into at least two sub-areas; respectively assigning weights to the first reference difference and the second reference difference according to the dirt condition of the sub-region; A compensation strategy is obtained by performing a weighted average according to the first reference difference, the second reference difference, and their assigned weight values.

Images