CN115494483A - Laser vehicle type detection calibration device and calibration method - Google Patents

Abstract

The application belongs to the technical field of intelligent vehicle information acquisition devices and methods, and discloses a laser vehicle type detection calibration device and a laser vehicle type detection calibration method. Laser motorcycle type detects calibrating device, including straight telescopic horizontal pole, the stabilizer blade that the multiunit can stretch out and draw back from top to bottom is connected to the horizontal pole below, and horizontal pole middle part fixed mounting has the spirit level, and horizontal pole one end has the laser indicator of perpendicular to horizontal pole, and the horizontal pole below still another can be clockwise and the horizontal pole of the rotatory tape angle scale of anticlockwise. The adjustable calibration device is suitable for uneven road surfaces and is convenient to operate; the height and the distance of the laser scanner are calibrated, and the precision is high; errors generated by displacement in the later stage of the equipment can be eliminated through calibration, and the overhead working truck is not required to be used for secondary position adjustment, so that manpower and material resources are saved.

Description

Laser vehicle type detection calibration device and calibration method

Technical Field

The application belongs to the technical field of intelligent vehicle information acquisition devices and methods, and particularly relates to a laser vehicle type detection calibration device and a laser vehicle type detection calibration method.

Background

The vehicle type detection is one of the key elements of traffic information acquisition, the laser scanning method is most widely applied to a vehicle type detection system due to the advantages of high precision, high scanning speed, few interference factors and the like, and the principle of the laser scanning method is mainly that a laser scanner scans the whole vehicle by modulated laser which is harmless to human eyes, and the vehicle type detection purpose is achieved by acquiring laser reflected by each position of the vehicle to carry out distance measurement so as to calculate vehicle appearance data. The data calculation needs to use the road surface below the laser scanner as a reference point, calculate the distance between the laser scanner and the road surface as a reference value, and then subtract the distance between the vehicle and the laser scanner to calculate the vehicle external dimension through a trigonometric function. This puts a high demand on the installation accuracy of the laser scanner, and if the laser scanner is not perpendicular to the ground or the scanning beam area is not perpendicular to the detection lane, the detection result will be inaccurate.

The level of the road surface also affects the detection data, and errors occur in the detected height and width of the vehicle when the vehicle passes over a non-level road surface below the laser scanner. And as the equipment erection time increases, the detection errors are caused by the vibration caused when the heavy-duty vehicle passes through or the displacement of the road surface and the laser scanner mounting upright post caused by geological motion.

The laser scanner is arranged at a height of more than 6 meters above the detection lane, needs the assistance of a road sealing vehicle and an overhead working truck, and wastes time and labor in installation and later calibration.

Disclosure of Invention

Aiming at the defects in the prior art, the application aims to provide the laser vehicle type detection and calibration device and the laser vehicle type detection and calibration method, and the device and the method can be used for calibrating a vehicle type detection system when errors occur after the device and the method are installed and used for a period of time, so that the detection result is accurate.

In order to achieve the purpose, the following technical scheme is adopted in the application:

the utility model provides a laser vehicle type detects calibrating device, includes straight telescopic horizontal pole, the stabilizer blade that the multiunit can stretch out and draw back from top to bottom is connected to the horizontal pole below, and horizontal pole middle part fixed mounting has the level bar, and horizontal pole one end has the laser designator of perpendicular to horizontal pole, and the horizontal pole below still another can be clockwise and the rotatory horizontal pole of taking the angle scale of counter-clockwise.

Preferably, the cross bar is provided with another cross bar with angle scales, which can rotate for maximum 20 degrees in the clockwise direction and the anticlockwise direction.

Preferably, the support leg is provided with scales and threads, and the support leg is connected with the cross rod through the threads.

When the laser vehicle type detection and calibration device is installed for the first time, the device comprises height and width detection calibration and length detection calibration, wherein the width and height detection calibration comprises the following steps:

11 To calibrate the perpendicularity of the laser beam scanning area of the laser scanner to the detection lane overlooking direction

Arranging the calibration device right below the laser scanner, wherein light rays emitted by the laser pointer are perpendicular to the cross rod of the calibration device, and irradiating the laser scanner through the laser pointer on the calibration device to determine whether the position of the calibration device is right below the laser scanner;

adjusting the calibrating device to be vertical to the detection lane in the overlooking direction, adjusting the width of a cross bar of the calibrating device to the lane width, and adjusting each support leg of the calibrating device through a horizontal ruler to enable the cross bar to be horizontal and each support leg to be stably contacted with the ground;

starting a laser scanner, and setting a laser beam scanning angle to enable a starting laser beam to be capable of being irradiated to one side edge of a lane and enable an ending laser beam to be capable of being irradiated to the other side edge of the lane; checking the distance detected by each laser beam of the laser scanner within a set scanning angle, wherein the correct distance value is the trend from small to large, and ensuring that all the laser beams of the laser scanner are scanned onto the cross bar of the calibration device within the set scanning angle;

12 ) calibrating a vertical laser beam in the elevational direction of the laser scanner

The laser beam with the shortest distance measured after the calibration in the step 11) is perpendicular to the calibration device, and the laser beam is set as an initial laser beam which is used as a necessary condition for calculating the width and the height of the vehicle at the later stage of vehicle type detection;

13 ) calibrating laser scanner horizontal distance

Adjusting a cross bar of the calibrating device to enable initial light beams of the two laser scanners to just respectively irradiate the corresponding edges of the cross bar;

using a trigonometric function l1 'sin α', calculating the length of the cross bar of the calibration device at the time, i.e. the horizontal distance between the two laser scanners, where α 'is the angle between the edge laser beam and the starting laser beam, and l1' is the distance from the laser scanner to the edge of the cross bar opposite to the diagonal measured by the edge laser beam;

14 Width and height detection

When the width and the height of a vehicle are calculated, firstly, the vertical height H1 from the laser scanner to the ground is measured, the distance l1 from the vehicle roof to the laser scanner is measured by a laser beam forming an included angle alpha with an initial laser beam, the horizontal distance w1 from the vehicle roof to the laser scanner is obtained by using a trigonometric function l1 Sin alpha, and the height H1 from the vehicle roof to the laser scanner is obtained by using l1 Cos alpha; the vertical height H2 of the other laser scanner from the ground, the horizontal distance w2 of the roof from the laser scanner and the height H2 of the roof from the laser scanner are obtained by the same method; because the vehicles are loaded with different cargos, the highest point and the widest point are not necessarily at the two top points of the vehicles, and the w1, w2 and the h1, h2 of each laser beam in the starting angles and the ending angles of the two laser scanners need to be calculated, and the minimum value of the w1, w2 and the h1, h2 is taken as the final calculation basis.

The real width of the vehicle is D-w1-w2, and D is the horizontal distance between the two laser scanners;

one side of the real height of the vehicle is H1-H1, and the other side is H2-H2.

Furthermore, the real height of the vehicle is the maximum value when the vehicle is applied to ultrahigh detection, and the average value is obtained when the vehicle type is distinguished.

The length detection calibration specifically comprises the following steps:

21 Calibrating the laser scanner laser beam scan area and detecting the lane look-down direction levelness

The length detection uses a laser scanner, a calibration device is arranged under the laser scanner, the calibration device is parallel to a detection lane in the overlooking direction, a cross bar of the calibration device is adjusted to be longest, and each support leg of the calibration device is adjusted to enable the cross bar to be horizontal and each support leg to be stably contacted with the ground;

starting a laser scanner, and setting a laser beam scanning angle to enable an initial laser beam to be capable of irradiating the edges of the two sides of the cross bar of the calibration device; ensuring that all laser beams of the laser scanner are scanned onto the cross bar of the calibrating device within a set scanning angle;

22 Length detection

The beam length c can be calculated from the distance a measured by the starting laser beam, the distance b measured by the ending laser beam, and the angle γ between the two laser beams, using the formula: c. C ² ＝a ² +b ² -2*a*b*Cosγ。

Preferably, in steps 11) and 21), the respective legs of the calibrating device are adjusted so that the top surface of the cross bar is 500mm from the ground.

Preferably, the laser scanners on both sides need to be calibrated separately in steps 11) and 12).

Preferably, in step 13), if the ending laser beam of the laser scanner is emitted outside the calibration device, each laser beam should be searched forward from the ending laser beam, and the laser beam with the measured distance corresponding to the value of H '÷ Sin α is found, H' is the height of the laser scanner from the calibration device, α is the angle between each laser beam and the starting beam, the angle between each laser beam and the starting beam is a fixed value, and the angle can be obtained by multiplying the difference between the serial numbers of the laser beams by the fixed angle, and then the laser beam is used as the ending laser beam.

Further, in step 13), the measuring tape is used for measuring the length of the cross bar of the calibrating device to verify the calculation result and confirm that the edge laser beam is accurately found.

Further, in step 13), the horizontal distance D between the two laser scanners is calculated again in the same manner for the other laser scanner, if the error of the calculation result is less than 2.5cm, the calibration is successful, otherwise, the calibration needs to be performed again; the average of the two horizontal distances is calculated as the final two laser scanner horizontal distances D.

Further, in step 22), the length of the cross bar of the current calibrating device is measured by a tape measure and compared with the calculated length of the cross bar, if the error of the calculation result is less than 2.5cm, the calibration is successful, otherwise, the levelness of the cross bar of the narrow-adjusting calibrating device is required to be recalibrated, and the levelness of the laser beam scanning area and the levelness of the overlooking direction of the detected lane are not enough.

Further, when a detection error occurs after the laser scanner is installed and used for a period of time, the width and height detection calibration is performed according to the following steps:

the laser scanners on two sides need to be calibrated separately, the calibration devices are arranged under the laser scanners, the laser scanners are irradiated by highlight laser indicators on the calibration devices to determine whether the positions of the calibration devices are under the laser scanners, the calibration devices are perpendicular to a detection lane in the overlooking direction, the width of a cross bar of the calibration devices to the lane is adjusted, and all support legs of the calibration devices are adjusted by a leveling rod to enable the cross bar to be horizontal and all the support legs to be in stable contact with the ground;

starting a laser scanner, and setting a laser beam scanning angle to enable a starting laser beam to be capable of being irradiated to one side edge of a lane and enable an ending laser beam to be capable of being irradiated to the other side edge of the lane;

checking the distance detected by each laser beam of the laser scanner within a set scanning angle, wherein the correct distance value is the trend from small to large, and ensuring that all the laser beams of the laser scanner are scanned onto the cross bar of the calibrating device within the set scanning angle; if all the laser beams are not scanned on the cross bar of the calibration device but are scanned on the ground, the cross bar with the angle scales needs to be rotated out of the calibration device, the distance detected by each laser beam of the laser scanner in a set scanning angle is checked, the rotating angle of the cross bar with the angle scales is adjusted, the verticality deviation of the laser scanner and a detection lane in the overlooking direction is found, and the current deviation angle theta is recorded through the angle scales;

continuously calibrating the vertical laser beam in the front-view direction of the laser scanner, and setting the laser beam with the shortest distance measured after the last calibration as the initial laser beam, wherein the laser beam is vertical to the calibration device;

then calibrating the horizontal distance of the laser scanners, rotating the whole calibrating device to the deflection direction of a laser beam scanning area, then adjusting the cross bar to the edge of a lane, and calculating the horizontal distance D' between the two laser scanners by a trigonometric function l1 sin alpha cos theta; calculating the other laser scanning in the same mode again, if the error between the two calculation results and the measuring result of the tape measure is less than 2.5cm, the calibration is successful, otherwise, the theta angle is inaccurate, and the calibration needs to be performed again;

when the width and the height of a vehicle are calculated, firstly, the vertical height H1 from the laser scanner to the ground is measured, the distance l1 from the vehicle roof to the laser scanner is measured by a laser beam forming an included angle alpha with an initial laser beam, and the horizontal distance w1' from the vehicle roof to the laser scanner is obtained by using a trigonometric function l1, sin alpha Cos theta, and the height H1 from the vehicle roof to the laser scanner is obtained by using a trigonometric function l1, cos alpha Cos theta; obtaining the vertical height H2 of another laser scanner from the ground, the horizontal distance w2' of the roof from the laser scanner and the height H2 of the roof from the laser scanner by using the same method; because the vehicles are loaded with different cargos, the highest point and the widest point are not necessarily at the two top points of the vehicles, and the w1', w2' and the h1, h2 of each laser beam in the starting angles and the ending angles of the two laser scanners need to be calculated, and the minimum value of the w1', w2' and the h1, h2 is taken as the final calculation basis.

The real width of the vehicle is D ' -w1' -w2';

one side of the real height of the vehicle is H1-H1, and the other side is H2-H2;

the length detection calibration is carried out according to the following steps:

arranging a calibration device under the laser scanner, wherein the calibration device is parallel to a detection lane in the overlooking direction, extending a cross bar of the calibration device to the maximum, and adjusting each support leg of the calibration device to enable the cross bar to be horizontal and each support leg to be stably contacted with the ground;

starting a laser scanner, and setting a laser beam scanning angle to enable initial laser beams to be emitted to the edges of two sides of a cross bar of the calibration device;

checking the distance detected by each laser beam of the laser scanner within a set scanning angle, wherein the correct distance value is the trend from large to small to large; if all laser beams are not scanned on the cross bar of the calibration device but scanned on the ground, the cross bar with the angle scales needs to be rotated out of the calibration device, the distances detected by the laser scanners by the laser beams in the set scanning angle are checked, the rotating angles of the cross bar with the angle scales are adjusted, the distance values detected by the laser beams tend to increase from large to small to large, the parallelism deviation between the found laser scanners and the detection lane in the overlooking direction is indicated, and the current deviation angle omega is recorded through the angle scales;

the cross bar length c can be calculated by the distance a measured by the starting laser beam, the distance b measured by the ending laser beam and the included angle gamma of the two laser beams, and the formula is used: c. C ² ＝(a ² +b ² -2*a*b*Cosγ)cosω*。

Compared with the prior art, the invention has the following beneficial effects:

(1) The adjustable calibration device is suitable for uneven road surfaces and is convenient to operate;

(2) The height and the distance of the laser scanner are calibrated, and the precision is high;

(3) Errors generated by displacement in the later stage of the equipment can be eliminated through calibration, and the overhead working truck is not needed to be used for secondary position adjustment, so that manpower and material resources are saved.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

FIG. 1 is a schematic structural diagram of a laser vehicle type detection and calibration device;

FIG. 2 is a schematic view of a width and height detection calibration;

FIG. 3 is a graph of distance values detected by the laser scanner within a set scanning angle during the width and height detection calibration;

FIG. 4 is a schematic view of a vertical laser beam in the elevational direction of a collimated laser scanner;

FIG. 5 is a schematic view of calibrating the horizontal distance of the laser scanner;

FIG. 6 is a schematic view of the height and width detection of a vehicle;

FIG. 7 is a schematic diagram of a length detection calibration;

FIG. 8 is a schematic diagram showing the setting of the scanning angle of the laser beam to enable the initial laser beam to irradiate the two side edges of the cross bar of the calibration device during the length detection and calibration;

FIG. 9 is a graph of distance values detected by the laser scanner for each laser beam within a set scanning angle during length detection calibration;

FIG. 10 is a schematic illustration of a deviated laser beam scanning area and a correct laser beam scanning area;

FIG. 11 is a graph of distance values measured by a correct laser beam during the length detection calibration;

FIG. 12 is a schematic view of length detection;

FIG. 13 is a schematic view of a width and height detection calibration;

FIG. 14 is a schematic diagram of a length detection calibration.

The labels in the figure are: 1-calibration device, 2-laser scanner, 3-laser scanner 1, 4-laser scanner 2, 5-cross bar, 6-support, 7-laser indicator, 8-level bar, 9-cross bar with angle scale.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.

A laser vehicle type detection and calibration device comprises a straight telescopic cross rod, wherein a plurality of groups of support legs capable of stretching up and down are connected to the lower portion of the cross rod, a horizontal ruler 8 is fixedly installed in the middle of the cross rod, one end of the cross rod is provided with a high-brightness laser indicator 7 perpendicular to the cross rod, for example, a laser indicator with the model number of LHGD-22100-300mw can be selected, another cross rod 9 with angle scales and capable of rotating in the clockwise/anticlockwise direction by 20 degrees at most is arranged below the cross rod, and the cross rod with the angle scales is folded below the upper cross rod at ordinary times, as shown in figure 1. The supporting legs are provided with scales and threads, and the supporting legs are connected with the cross rod through the threads.

The laser vehicle type detection and calibration device is installed for the first time according to the following steps:

and (3) detecting and calibrating the width and the height:

11 To calibrate the perpendicularity of the laser scanner's laser beam scanning area to the detection lane's overlooking direction

The correct laser beam scanning area should be perpendicular to the detection lane in the top view direction, so that the width scanned by the laser beam when the vehicle passes under the laser scanner is the true width of the vehicle, otherwise the measured width is increased, as shown in fig. 2;

the laser scanners on two sides need to be calibrated separately, the calibration device is arranged under the laser scanners, light rays emitted by the laser indicators are perpendicular to the cross bars of the calibration device, and the laser indicators on the calibration device irradiate the laser scanners to determine whether the positions of the calibration device are under the laser scanners;

adjusting the calibrating device to be vertical to the detection lane in the overlooking direction, extending the cross bar of the calibrating device to the width of the lane, adjusting each support leg of the calibrating device through a horizontal ruler to enable the cross bar to be horizontal and each support leg to be stably contacted with the ground, and enabling the top surface of the cross bar to be 500mm away from the ground (the value can be determined according to the field condition);

starting a laser scanner, and setting a laser beam scanning angle to enable a starting laser beam to be capable of being irradiated to one side edge of a lane and enable an ending laser beam to be capable of being irradiated to the other side edge of the lane;

checking the distances detected by each laser beam of the laser scanner within the set scanning angle, wherein the correct distance value is a trend from small to large, the curve is shown as a solid line in fig. 3, if the distance value is wholly increased as shown as a dotted line in fig. 3, the fact that all the laser beams are not scanned on the cross bar of the calibrating device but are scanned on the ground is shown, and at the moment, the installation angle of the laser scanner needs to be adjusted to enable the scanning area of the laser beams to be perpendicular to the overlooking direction of the detected lane, and the distances detected by each laser beam within the set scanning angle to be in accordance with the curve shown as the solid line in fig. 3. Generally, according to the width of the lane, the set scanning angle is 30-45 degrees, the horizontal axis is the serial number of the laser beam, and the vertical axis is the measured distance, so that the corresponding curve is obtained, if the laser beam is irradiated to the ground instead of the calibration device, the measured distance will increase suddenly, and the laser beam after the laser beam is irradiated to the ground will also be irradiated to the ground (because the scanner is askew or the laser beam is already irradiated outside the edge of the calibration device) as shown in the dotted line part of fig. 3, and the laser beam on the right of the initial +2 laser beam is the last laser beam irradiated to the calibration device.

12 To calibrate the vertical laser beam in the elevational direction of the laser scanner

As shown in fig. 4, the laser beam with the shortest distance measured after calibration in step 11) should be perpendicular to the calibration device, and this laser beam is set as the starting laser beam, which will be the necessary condition for calculating the vehicle width and height in the late stage of vehicle type detection; the 2 laser scanners need to be calibrated separately because installation or mechanical errors may cause them to be out of level with each other causing height differences and their respective starting laser beam numbers to be different.

13 ) calibrating laser scanner horizontal distance

Shortening two ends of a cross bar of a calibration device, enabling initial light beams of two laser scanners to just respectively irradiate corresponding edges of the cross bar, wherein an ending laser beam of the laser scanner 1 shown in fig. 5 already irradiates the calibration device, at the moment, each laser beam is required to be searched forwards from the ending laser beam, a laser beam with a distance which is in accordance with a value of H '÷ Sin alpha is found out, H' is the height of the laser scanner from the calibration device, alpha is an included angle between each laser beam and the initial light beam, the included angle of each laser beam is a fixed value, the laser beam can be obtained by multiplying the difference of laser beam serial numbers by the fixed included angle, and at the moment, the laser beam is used as the ending laser beam. The solid line segment next to the dotted line in the figure represents the laser beam emitted by the laser scanner 1 beyond the distal edge of the calibration device, and the dotted line segment is the laser beam emitted by the laser scanner 1 beyond the distal edge of the calibration device.

Calculating the length of the cross bar of the calibrating device at the moment, namely the horizontal distance between the two laser scanners by using a trigonometric function l1 '. Sin alpha', wherein alpha 'is an included angle between the edge laser beam and the initial laser beam, and l1' refers to the distance from the laser scanner to the edge of the cross bar opposite to the oblique angle measured by the edge laser beam; the length of the cross bar of the calibrating device measured by the measuring tape can be used for verifying the calculation result and confirming that the edge laser beam is accurately found. The horizontal distance D between the two laser scanners is calculated again in the same manner for the laser scanner 2, and if the error of the two calculations is less than 2.5cm, the calibration is successful, otherwise the calibration needs to be re-performed. And calculating the average value of the two horizontal distances as the final two laser scanner horizontal distances D.

14 Width and height detection

As shown in fig. 6, when calculating the width and height of the vehicle, the vertical height H1 from the ground of the laser scanner 1 is measured, the distance l1 from the roof to the laser scanner 1 is measured by the laser beam forming an angle α with the starting laser beam, the horizontal distance w1 from the roof to the scanner 1 is obtained by using a trigonometric function l1 × Sin α, and the height H1 from the roof to the scanner 1 is obtained by using l1 × Cos α. The vertical height H2 of the laser scanner 2 from the ground, the horizontal distance w2 of the roof from the scanner 2, and the height H2 of the roof from the scanner 2 are obtained using the same method. Because the vehicles are loaded with different cargos, the highest point and the widest point are not necessarily at two top points of the vehicles, and the w1, w2 and h1, h2 of each laser beam in the starting angle and the ending angle of the two laser scanners need to be calculated, and the minimum value of the w1, w2 and h1, h2 is taken as the final calculation basis.

The real width of the vehicle is D-w1-w2, and D is the horizontal distance between the two laser scanners measured in the previous step.

One side of the real height of the vehicle is H1-H1, the other side of the real height of the vehicle is H2-H2, the maximum value is taken when the ultrahigh detection is applied, and the average value is taken when the vehicle type is distinguished.

It should be noted that, since the included angles of the plurality of laser beams are different, taking the laser scanner 1 as an example, α is a variation value from 0 to β, β is a maximum angle of the laser beam at which the scanner 1 can measure the distance of the roof, the return distance of the laser beam that has been emitted to the distant road surface is too large or too wide, and l (distance between the vehicle side and the scanner), w (horizontal distance between the vehicle side and the scanner), and h (height between the roof and the scanner) measured by each laser beam are different, and the minimum value of w and the minimum value of h should be taken as the final calculation basis.

Length detection calibration:

21 To calibrate the laser scanner laser beam scanning area and to detect the level of the overhead direction of the roadway

The correct laser beam scanning area should be parallel to the detection lane in the top view direction, so that the length scanned by the laser beam when the vehicle passes under the laser scanner is the real vehicle length of the vehicle, otherwise the measured length is increased, as shown in fig. 7;

the length detection uses a laser scanner, arranges calibrating device under the laser scanner, and calibrating device is on a parallel with the detection lane in overlooking the direction, and the extension calibrating device horizontal pole is at the biggest (theoretically the horizontal pole length is the biggest range effect of laser scanner, but is limited to machining precision, cost aspect and considers and can not make too long horizontal pole), adjusts each stabilizer blade of calibrating device, makes horizontal and each stabilizer blade of horizontal pole stable contact ground, and horizontal pole top surface is 500mm apart from ground height (this value can be according to the field situation confirms).

As shown in fig. 8, the laser scanner is turned on, and the scanning angle of the laser beam is set so that the initial laser beam can be irradiated to both side edges of the cross bar of the alignment device.

Looking up the distances detected by each laser beam of the laser scanner within the set scanning angle, the correct distance value is the trend from large to small to large, the curve is shown as the solid line in fig. 9, if the distance value is increased as a whole as shown by the broken line in fig. 9, it is indicated that all the laser beams are not scanned onto the cross bar of the calibration device but are scanned onto the ground, at this time, the installation angle of the laser scanner needs to be adjusted, so that the scanning area of the laser beam is parallel to the detection lane in the overlooking direction, and the distances detected by each laser beam within the set scanning angle are made to conform to the curve shown as the solid line in fig. 9.

Here, the scanning angle of the laser beam is generally set to be 30 to 60 degrees, the horizontal axis is the serial number of the laser beam, and the vertical axis is the measured distance, so that the corresponding curve is obtained.

As shown in fig. 10, the deviated laser beam scanning areas, in which only a middle portion of the laser beams from left to right strikes the calibration device and the others strike the ground, may occur in the case of the middle solid line (short distance) between the two dotted lines (long distance) in fig. 9, and the correct laser beam scanning area should measure no abrupt change in distance, as shown in fig. 11.

22 Length detection

As shown in fig. 12, the beam length c can be calculated from the distance a measured by the starting laser beam and the distance b measured by the ending laser beam, and the angle γ between the two laser beams, using the formula: c. C ² ＝a ² +b ² -2*a*b*Cosγ

And measuring the length of the cross bar of the current calibrating device by using a measuring tape, comparing the length with a calculation result, if the error of the calculation result is less than 2.5cm, the calibration is successful, otherwise, the levelness of the laser beam scanning area and the overlooking direction of the detection lane is not enough, and the levelness needs to be recalibrated by narrowing the cross bar of the calibrating device.

Further, when the detection error occurs after the laser scanner is installed and used for a period of time, the calibration is carried out according to the following steps:

1. width and height detection calibration

As in the installation, laser scanners on two sides need to be calibrated separately, a calibration device is arranged under the laser scanners, the laser scanners can be irradiated by highlight laser indicators on the calibration device to determine whether the position of the calibration device is under the laser scanners, the calibration device is perpendicular to a detection lane in the overlooking direction, the cross bar of the calibration device is extended to the width of the lane, each support leg of the calibration device is adjusted by a leveling rod, the cross bar is horizontal and stably contacts the ground, and the top surface of the cross bar is 500mm away from the ground (the value can be determined according to the field condition);

starting a laser scanner, and setting a laser beam scanning angle to enable a starting laser beam to be emitted to one side edge of a lane and enable an ending laser beam to be emitted to the other side edge of the lane;

checking the distance detected by each laser beam of the laser scanner within a set scanning angle, wherein the correct distance value is a trend from small to large, if the distance value is integrally increased, the fact that all the laser beams are not scanned on the cross rod of the calibrating device but scanned on the ground is indicated, at the moment, the cross rod with the angle scales needs to be rotated out of the calibrating device, the distance detected by each laser beam of the laser scanner within the set scanning angle is checked, the rotating angle of the cross rod with the angle scales is adjusted, the distance value detected by each laser beam is a trend from small to large, a curve is shown as a solid line of a verticality calibration curve during installation, the fact that the verticality deviation between the laser scanner and a detection lane in the overlooking direction is found is indicated, and the current deviation angle theta is recorded through the angle scales, and is shown in fig. 13.

The alignment of the vertical laser beam in the elevational direction of the laser scanner is continued in the same way as during installation.

The horizontal distance of the laser scanner is then calibrated, in contrast to the calibration during installation, in which case the length calculated by means of the trigonometric function l1 x sin α is no longer the same as the length of the cross-bar of the calibration device measured by means of a measuring tape, since the laser beam scanning zone is no longer perpendicular to the test track in the top view. At the moment, the whole calibration device can be rotated to the deflection direction of a laser beam scanning area, then the cross arm is extended to the edge of a lane, the value obtained through the calculation of a trigonometric function l1 sin alpha cos theta is the horizontal distance D between the two laser scanners, the laser scanners 2 are calculated again in the same mode, if the error between the two calculation results and the measuring result of the measuring tape is smaller than 2.5cm, the calibration is successful, otherwise, the theta angle is inaccurate, and the recalibration is needed.

The result of the vehicle width detection needs to be multiplied by cos theta to obtain a corrected correct value, and the vehicle height detection is not influenced by the deflection of the laser beam scanning area.

2. Length detection calibration

As during installation, arrange calibrating device under laser scanner, calibrating device is on a parallel with the detection lane in overlooking the direction, and extension calibrating device horizontal pole is to the biggest, adjusts each stabilizer blade of calibrating device, makes horizontal pole level and each stabilizer blade stable contact ground, and the horizontal pole top surface is 500mm apart from ground height (this value can be confirmed according to the field situation).

And starting the laser scanner, and setting the scanning angle of the laser beam so that the initial laser beam can irradiate the edges of the two sides of the cross bar of the calibrating device.

Checking the distance detected by each laser beam of the laser scanner in a set scanning angle, wherein the correct distance value is a trend from large to small to large, if the distance value is integrally increased, the fact that all the laser beams are not scanned on the cross bar of the calibrating device but scanned on the ground is indicated, at the moment, the cross bar with the angle scales needs to be rotated out of the calibrating device, the distance detected by each laser beam of the laser scanner in the set scanning angle is checked, the rotating angle of the cross bar with the angle scales is adjusted, the distance value detected by each laser beam is a trend from large to small to large, a curve is shown as a solid line of a verticality calibrating curve during installation, the fact that the deviation of the parallelism between the laser scanner and a detected lane in the overlooking direction is found is indicated, and the current deviation angle omega is recorded through the angle scales, as shown in fig. 14.

The correct value after correction is obtained by multiplying the result by cos ω in the length calculation.

The foregoing description has described specific embodiments of the present invention. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention.

Claims (10)

1. The utility model provides a laser motorcycle type detects calibrating device which characterized in that, includes straight telescopic horizontal pole, the stabilizer blade that the multiunit can stretch out and draw back from top to bottom is connected to the horizontal pole below, and horizontal pole middle part fixed mounting has the level bar, and horizontal pole one end has the laser designator of perpendicular to horizontal pole, and the horizontal pole below still has another horizontal pole of taking the angle scale that can clockwise and anticlockwise rotate.

2. The laser vehicle type detection and calibration device as claimed in claim 1, wherein another cross bar with an angle scale capable of rotating up to 20 degrees in clockwise and counterclockwise directions is further arranged below the cross bar; the supporting legs are provided with scales and threads, and the supporting legs are connected with the cross rod through the threads.

3. The calibration method of the laser vehicle type detection calibration device according to any one of claims 1-2, wherein the first installation of the laser vehicle type detection calibration device comprises a height and width detection calibration and a length detection calibration, wherein the height and width detection calibration specifically comprises the following steps:

11 To calibrate the perpendicularity of the laser scanner's laser beam scanning area to the detection lane's overlooking direction

Arranging a calibration device right below the laser scanner, wherein light rays emitted by the laser pointer are perpendicular to a cross bar of the calibration device, and irradiating the laser scanner through the laser pointer on the calibration device to determine whether the position of the calibration device is right below the laser scanner;

adjusting the calibrating device to be vertical to the detection lane in the overlooking direction, adjusting the width of a cross bar of the calibrating device to the lane width, and adjusting each supporting leg of the calibrating device through a horizontal ruler to enable the cross bar to be horizontal and each supporting leg to be stably contacted with the ground;

starting a laser scanner, and setting a laser beam scanning angle to enable a starting laser beam to be emitted to one side edge of a lane and enable an ending laser beam to be emitted to the other side edge of the lane; checking the distance detected by each laser beam of the laser scanner within a set scanning angle, wherein the correct distance value is the trend from small to large, and ensuring that all the laser beams of the laser scanner are scanned onto the cross bar of the calibrating device within the set scanning angle;

12 ) calibrating a vertical laser beam in the elevational direction of the laser scanner

The laser beam with the shortest distance measured after the calibration in the step 11) is perpendicular to the calibration device, and the laser beam is set as an initial laser beam which is used as a necessary condition for calculating the width and the height of the vehicle at the later stage of vehicle type detection;

13 ) calibrating laser scanner horizontal distance

Adjusting a cross bar of the calibrating device to enable initial light beams of the two laser scanners to just respectively irradiate the corresponding edges of the cross bar;

using a trigonometric function l1 'sin α', calculating the length of the cross bar of the calibration device at the time, i.e. the horizontal distance between the two laser scanners, where α 'is the angle between the edge laser beam and the starting laser beam, and l1' is the distance from the laser scanner to the edge of the cross bar opposite to the diagonal measured by the edge laser beam;

14 Width and height detection

When the width and the height of a vehicle are calculated, firstly, the vertical height H1 from the laser scanner to the ground is measured, the distance l1 from the vehicle roof to the laser scanner is measured by a laser beam forming an included angle alpha with an initial laser beam, the horizontal distance w1 from the vehicle roof to the laser scanner is obtained by using a trigonometric function l1 Sin alpha, and the height H1 from the vehicle roof to the laser scanner is obtained by using l1 Cos alpha; obtaining the vertical height H2 of another laser scanner from the ground, the horizontal distance w2 of the roof from the laser scanner and the height H2 of the roof from the laser scanner by using the same method; because the vehicles are loaded with different cargos, the highest point and the widest point are not necessarily at the two top points of the vehicles, the w1, w2 and h1, h2 of each laser beam in the starting angle and the ending angle of the two laser scanners are required to be calculated, and the minimum value of the w1, w2 and h1, h2 is taken as the final calculation basis;

the real width of the vehicle is D-w1-w2, and D is the horizontal distance between the two laser scanners;

one side of the real height of the vehicle is H1-H1, and the other side of the real height of the vehicle is H2-H2;

the real height of the vehicle is obtained by taking the maximum value when the ultrahigh detection is applied and taking the average value when the vehicle type is distinguished;

the length detection calibration specifically comprises the following steps:

21 Calibrating the laser scanner laser beam scan area and detecting the lane look-down direction levelness

The length detection uses a laser scanner, a calibration device is arranged under the laser scanner, the calibration device is parallel to a detection lane in the overlooking direction, a cross bar of the calibration device is adjusted to be longest, and each support leg of the calibration device is adjusted to enable the cross bar to be horizontal and each support leg to be stably contacted with the ground;

starting a laser scanner, and setting a laser beam scanning angle to enable an initial laser beam to be capable of irradiating the edges of the two sides of the cross bar of the calibration device; ensuring that all laser beams of the laser scanner are scanned onto the cross bar of the calibrating device within a set scanning angle;

22 Length detection

The beam length c can be calculated from the distance a measured by the starting laser beam, the distance b measured by the ending laser beam, and the angle γ between the two laser beams, using the formula: c. C ² ＝a ² +b ² -2*a*b*Cosγ。

4. The method for calibrating a laser vehicle type detection calibration device according to claim 3, wherein in steps 11) and 21), each leg of the calibration device is adjusted so that the top surface of the cross bar is 500mm from the ground.

5. The calibration method of the laser vehicle type detection calibration apparatus according to claim 3, wherein in steps 11) and 21), the laser scanners on both sides need to be separately calibrated.

6. The calibration method of the laser vehicle type detection calibration device according to claim 3, wherein in step 13), after adjusting the length of the cross bar of the calibration device, if the ending laser beam of a certain laser scanner is emitted to the outside of the calibration device, each laser beam should be searched forward from the ending laser beam, and a laser beam whose measured distance matches the value of H '÷ Sin α is found, H' is the height of the laser scanner from the calibration device, α is the angle between each laser beam and the starting beam, the angle between each laser beam and the starting beam is a fixed value, and the angle is determined by multiplying the difference between the serial numbers of the laser beams by the fixed angle, and the laser beam is taken as the ending laser beam.

7. The method for calibrating a laser vehicle type detection and calibration device according to claim 3, wherein in step 13), the laser beam calculation result is verified by measuring the length of the cross bar of the calibration device with a tape measure, and it is confirmed that the edge laser beam is accurately found.

8. The calibration method of the laser vehicle type detection calibration device according to claim 3, wherein in step 13), the horizontal distance D between the two laser scanners is calculated again in the same manner for the other laser scanner, if the error of the calculation results is less than 2.5cm, the calibration is successful, otherwise, the calibration needs to be performed again; the average of the two horizontal distances is calculated as the final two laser scanner horizontal distances D.

9. The method for calibrating the laser vehicle type detection and calibration device of claim 3, wherein in step 22), the length of the cross bar of the current calibration device is measured by a tape measure and compared with the calculated length of the cross bar, if the error of the calculation result is less than 2.5cm, the calibration is successful, otherwise, the levelness of the cross bar of the laser beam scanning area and the detection lane in the overlooking direction is not enough, and the levelness of the cross bar of the calibration device needs to be narrowed.

10. The laser vehicle type detection and calibration device according to any one of claims 1 to 2, a calibration method when a detection error occurs after a laser scanner is installed and used for a certain period of time, wherein the width and height detection calibration is performed as follows:

laser scanners on two sides need to be calibrated separately, a calibration device is arranged under the laser scanners, the laser scanners are irradiated by highlight laser indicators on the calibration device to determine whether the position of the calibration device is under the laser scanners, the calibration device is perpendicular to a detection lane in the overlooking direction, the width of a cross bar of the calibration device from the cross bar to the lane is adjusted, and each support leg of the calibration device is adjusted by a leveling rod to enable the cross bar to be horizontal and each support leg to be stably contacted with the ground;

starting a laser scanner, and setting a laser beam scanning angle to enable a starting laser beam to be capable of being irradiated to one side edge of a lane and enable an ending laser beam to be capable of being irradiated to the other side edge of the lane;

checking the distance detected by each laser beam of the laser scanner within a set scanning angle, wherein the correct distance value is the trend from small to large, and ensuring that all the laser beams of the laser scanner are scanned onto the cross bar of the calibrating device within the set scanning angle; if all laser beams are not scanned on the cross bars of the calibration device but are scanned on the ground, the cross bars with the angle scales need to be rotated out of the calibration device, the distances detected by the laser scanners by the laser beams in the set scanning angle are checked, the rotating angles of the cross bars with the angle scales are adjusted, the verticality deviation between the laser scanners and the detection lane in the overlooking direction is found, and the current deviation angle theta is recorded through the angle scales;

continuously calibrating the vertical laser beam in the front-view direction of the laser scanner, and setting the laser beam with the shortest distance measured after the last calibration as the initial laser beam, wherein the laser beam is vertical to the calibration device;

then calibrating the horizontal distance of the laser scanners, rotating the whole calibrating device to the deflection direction of a laser beam scanning area, then adjusting the length of a cross bar to the edge of a lane, and calculating the horizontal distance D' between the two laser scanners through a trigonometric function l1 sin alpha cos theta; calculating the other laser scanning in the same mode again, if the error between the two calculation results and the measuring result of the tape measure is less than 2.5cm, the calibration is successful, otherwise, the theta angle is inaccurate, and the calibration needs to be performed again;

when the width and the height of a vehicle are calculated, firstly, the vertical height H1 from the laser scanner to the ground is measured, the distance l1 from the vehicle roof to the laser scanner is measured by the laser beam forming an included angle alpha with the initial laser beam, and the horizontal distance w1' from the vehicle roof to the laser scanner, and the height H1 from the vehicle roof to the laser scanner are obtained by using a trigonometric function l1, sinalphacos theta; obtaining the vertical height H2 of another laser scanner from the ground, the horizontal distance w2' of the roof from the laser scanner and the height H2 of the roof from the laser scanner by using the same method; because the vehicles are loaded with different cargos, the highest point and the widest point are not necessarily at the two top points of the vehicles, the w1', w2' and h1, h2 of each laser beam in the starting angle and the ending angle of the two laser scanners are required to be calculated, and the minimum value of the w1', w2' and h1, h2 is taken as the final calculation basis;

the real width of the vehicle is D ' -w1' -w2';

one side of the real height of the vehicle is H1-H1, and the other side is H2-H2;

the length detection calibration is carried out according to the following steps:

arranging a calibration device under the laser scanner, wherein the calibration device is parallel to a detection lane in the overlooking direction, extending a cross bar of the calibration device to the maximum, and adjusting each support leg of the calibration device to enable the cross bar to be horizontal and each support leg to be stably contacted with the ground;

starting a laser scanner, and setting a laser beam scanning angle to enable an initial laser beam to be capable of irradiating the edges of the two sides of the cross bar of the calibration device;

checking the distance detected by each laser beam of the laser scanner within a set scanning angle, wherein the correct distance value is the trend from large to small to large; if all laser beams are not scanned on the cross bar of the calibration device but scanned on the ground, the cross bar with the angle scales needs to be rotated out of the calibration device, the distances detected by the laser scanners by the laser beams in the set scanning angle are checked, the rotating angles of the cross bar with the angle scales are adjusted, the distance values detected by the laser beams tend to increase from large to small to large, the parallelism deviation between the found laser scanners and the detection lane in the overlooking direction is indicated, and the current deviation angle omega is recorded through the angle scales;

the beam length c can be calculated from the distance a measured by the starting laser beam, the distance b measured by the ending laser beam, and the angle γ between the two laser beams, using the formula: c. C ² ＝(a ² +b ² -2*a*b*Cosγ)cosω*。

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