ETC door frame illumination glare measuring method and device

Abstract

The invention discloses a method and a device for measuring ETC (electronic toll collection) door frame illumination glare, and belongs to the field of expressway environment illumination detection. The device comprises a positioner, a reflected signal demodulator, a reflected signal receptor, a transmitted signal modulator, a signal transmitter, a transmitted signal demodulator, a transmitted signal receptor, a transparent and reflective mirror group, a detector, an upper vertical plane illumination detector, a camera and a switcher. The calculation formula of the ground brightness is obtained by measuring the reflectivity of the ground below the ETC door frame and measuring the ground brightness, the ground brightness is obtained at a short distance, and the problems that the interference of external stray light is much and the measurement accuracy of a brightness meter is reduced when the distance is long due to the fact that the brightness meter and the like are used for measuring the brightness at a long distance are solved; the brightness of the light supplement lamp under different orders of magnitude is obtained through the switcher blades with different light transmittances, the sensitivity advantages of the left camera and the right camera in a high-brightness area and a low-brightness area are integrated, the system error is reduced, and an accurate comprehensive illumination value is obtained.

Description

Technical Field

[0001] The invention belongs to the field of highway environment lighting detection. Background Art

[0002] Threshold increment: When a glare source appears, in order to achieve the same good viewing conditions, the percentage by which the contrast between an object and its background needs to be increased. It is usually expressed as TI and is a quantitative indicator of the glare of lamps such as road lamps and ETC gantry fill lights.

[0003] ETC gantry lighting: Relying on the lighting facilities in the ETC gantry system to change the ambient light near the ETC gantry, the monitoring facilities in the ETC gantry system can accurately capture the license plate information or in-vehicle images of the moving vehicle. Its lighting facilities generally include highway vehicle license plate video automatic recognition fill-in lighting devices and traffic technology monitoring imaging fill-in lighting devices, which can be collectively referred to as fill-in lights.

[0004] With the completion of the construction of a strong transportation country and the deepening of the reform of the toll road system to cancel the provincial toll stations on expressways, the ETC gantry system has been applied on a large scale. Among them, the lighting system such as the fill light is an important part of the ETC gantry image recognition and monitoring system.

[0005] The traffic technical monitoring imaging fill-light device is installed on the ETC gantry. The vertical height from the target road is generally 6m. The fill-light device is installed on the upper side of the target road. The spatial angle formed by the reference axis of the traffic technical monitoring imaging fill-light device and the dividing line between the two roads is equal to 20°, and one is installed per lane.

[0006] The highway vehicle license plate video automatic recognition fill-light device is installed on the ETC gantry, with a vertical distance of 6.5m from the target road. It is installed directly above the center line of the target road, and one is installed per lane.

[0007] Figure 3 In the figure, S1 is the target road, S2 is the ETC gantry, S4 is the road adjacent to the target road, S9 is the dividing line between the two roads, S5 is the highway vehicle license plate video automatic recognition fill-in light device, S6 is the traffic technology monitoring imaging fill-in light device, S8 is the reference axis of the traffic technology monitoring imaging fill-in light device, and S7 is the center line of the target road. α is the spatial angle between the reference axis of the traffic technology monitoring imaging fill-in light device and the dividing line between the two roads, and its value is 20°.

[0008] However, during the operation of the ETC gantry system, the glare caused by the inappropriate selection and setting of the night lighting system, especially the fill light, has caused heated discussions. When the vehicle is driving at high speed, the temporary blindness caused by the glare of the disabled gantry lighting system of some ETC gantry will cause serious traffic safety accidents. The glare of the fill light has become a hot issue. In 2021, the Ministry of Transport responded to the concerns of netizens and organized various places to carry out highway network monitoring and gantry equipment inspections, and urged some provinces to further optimize the gantry fill lights to alleviate the impact of light intensity within a certain distance on night driving comfort.

[0009] Glare is a visual state that causes discomfort or reduces the ability to observe targets or details due to inappropriate brightness distribution or brightness range in the field of vision, or extreme brightness contrast. According to the effect classification of glare, it can be divided into discomfort glare and disabling glare. Glare is essentially a product of the combination of photometry and optometry, which is mainly reflected in the physiological reaction of the human eye to the changes in external light. Survey results show that long-term living in an environment with poor lighting, such as inappropriate light illumination, uneven light distribution, excessive glare, etc., is extremely harmful to human health. Therefore, accurate measurement of glare can effectively prevent and avoid the occurrence of safety problems.

[0010] Glare in road lighting is often quantitatively characterized by threshold increments. Recently, researchers have also proposed using threshold increments to characterize the glare level of ETC gantry fill lights. At present, there is no commercial technical solution for measuring the glare of ETC gantry fill lights. Similar technical solutions can be used to measure the glare of road street lights. The traditional glare measurement method is to combine traditional equipment such as illuminance meters, brightness meters, and tape measures for measurement. Since the response speed of illuminance meters and brightness meters is slow, they need to be measured in a static state. There are also methods that control the camera to measure the glare of street lights through the compilation of special software, or control the imaging brightness meter through special software to measure the glare of street lights, and then use the position measurement device to cooperate to calculate the threshold increment. Such equipment is also called a glare tester.

[0011] Current technology has the following disadvantages:

[0012] 1) Existing technologies cannot measure the glare of ETC gantry fill lights. The placement of ETC gantry fill lights is completely different from that of road lights. ETC gantry fill lights are placed above the gantry that crosses the road, while road lights are placed on the roadside. ETC gantry fill lights are electromechanical facilities on highways. There are no street lights on highways, and the road surface brightness is very low, generally not exceeding 0.5cd / m 2 , and street lamps are electromechanical facilities on the road. Due to the lighting of adjacent street lamps, the ground brightness is relatively high, at 1.5cd / m 2Therefore, the impact of ETC gantry fill light and road lamp glare on the driver's vision is completely different.

[0013] 2) At present, conventional glare testers are static measurements, that is, they are stationary at a distance of several meters from the street lamp to be tested, take a static image, calculate the brightness of different points on the image, and finally get the threshold increment of the street lamp. This results in the need to close the road traffic when performing glare measurement, affecting the normal traffic on the road.

[0014] 3) The operation process is cumbersome, time-consuming, and the amount of data is too large. Manual real-time point measurement is required. The measurement results are easily affected by subjective factors such as the state of the tester and the point measurement habits, which will inevitably lead to large errors in the test results. Therefore, the traditional manual point measurement technology can no longer meet the needs of efficient, real-time and accurate on-site detection.

[0015] The present invention realizes the glare measurement of the ETC gantry fill light and realizes the measurement in a dynamic state. When the present invention is used to perform the glare measurement of the ETC gantry fill light, there is no need to block traffic.

[0016] The present invention is easy to operate and can measure the threshold increment, a quantitative evaluation index of glare, using a set of integrated devices. The observation position information, illumination information at the simulated human eye, and ground brightness information required for threshold increment calculation can be obtained using a set of integrated devices.

[0017] The present invention requires a shorter time. Using conventional means to measure the glare of a road lamp, according to statistics, it takes about 30 minutes at the fastest. However, using the present invention to measure the glare of the ETC gantry fill light, according to statistics, it generally only takes 3 minutes. Summary of the invention

[0018] The ETC gantry lighting glare measuring device of the present invention is mainly composed of a positioner, a data processing module, a reflection signal demodulator, a reflection signal receptor, a transmission signal modulator, a signal transmitter, a transmission signal demodulator, a transmission signal receptor, a transparent and reflective mirror group, a ground-off detector, a frame-off detector, an upper vertical illumination detector, a left camera, a middle camera, a right camera, a middle camera light tube, a switcher, a switcher controller, a support frame, a reference horizontal frame and the like. The hardware connection diagram is shown in FIG. Figure 1 shown.

[0019] Figure 1In the figure, 1 is a locator, 2 is a data processing module, 3-1 is a reflection signal demodulator, 3-2 is a reflection signal receptor, 4-1 is a transmission signal modulator, 4-2 is a signal transmitter, 5-1 is a transmission signal demodulator, 5-2 is a transmission signal receptor, 6 is a transparent and reflective mirror group, 7 is a ground-lift detector, 8 is a frame-lift detector, 9 is an upper vertical plane illumination detector, 10 is a left camera, 11 is a middle camera, 12 is a right camera, 13 is a middle camera light tube, 14 is a switcher, 15 is a switcher controller, 16 is a support frame, 17 is a reference horizontal frame, S1 is a target road, S2 is an ETC gantry, h is the vertical distance between the frame-lift detector and the ETC gantry, and d is the vertical distance between the ground-lift detector and the ground. The ground described in the figure is assumed to be horizontal.

[0020] The locator can be a positioning device based on a GPS receiving module or a positioning device based on a BDS receiving module to obtain the positioning information of the device.

[0021] The data processing module can be a computer, an industrial computer, a single-chip microcomputer, etc., which collects data output by the locator, reflection signal demodulator, transmission signal modulator, ground lift detector, frame lift detector, upper vertical surface illumination detector, left camera, middle camera, right camera, etc. through wired or wireless means, and controls the transmission signal demodulator, switch controller and other parts.

[0022] The reflected signal demodulator is a signal demodulation circuit that demodulates the signal output by the reflected signal receptor, and the demodulation method corresponds to the modulation method.

[0023] The transmitting signal modulator is a signal modulation circuit that controls the signal transmitter to emit a modulated optical signal. The modulation method may be a trigonometric function or the like.

[0024] The transmitting signal demodulator is a signal demodulation circuit that demodulates the signal output by the transmitting signal receptor, and the demodulation method corresponds to the modulation method.

[0025] The signal transmitter is a component that emits optical signals, and a single-wavelength laser is preferred. The wavelength can generally be selected from the infrared band, such as 905nm and 1550nm, which have relatively weak intensity in the solar spectrum.

[0026] The reflective mirror set is composed of a lens with a reflectivity of m1% and a transmittance of m2% and a corresponding bracket. The basic principle is to glue two lenses with different refractive indices together so that one lens surface reflects light and the other lens surface transmits light. It can also be to coat an optical film on one lens surface so that one surface reflects light and the other surface transmits light. m1+m2=100.

[0027] The central axis of the light beam emitted by the signal transmitter passes through the center point of the transparent and reflective mirror group. The energy of the light beam emitted by the signal transmitter is p, and the m2% part passes through the transparent and reflective mirror group, reflects from the ground, and enters the reflection signal receptor. After being demodulated by the reflection signal demodulator, the energy of the reflected light p2 is obtained. The m1% part of the light beam emitted by the signal transmitter is reflected by the transparent and reflective mirror group, enters the transmission signal receptor, and after being demodulated by the transmission signal demodulator, the energy of the sensed light beam p1 is obtained.

[0028] By using a single-wavelength laser to transmit signals and combining signal modulation and demodulation, interference from external ambient light can be avoided.

[0029] The ground detector is a component that measures the vertical distance from the ground, and can be a laser ranging module or an ultrasonic ranging module.

[0030] The off-gantry detector is a device for measuring the lighting glare of the ETC gantry. It is a component that measures the vertical distance from the ETC gantry when passing under the ETC gantry. It can be a laser ranging module, an ultrasonic ranging module, etc.

[0031] The measuring surface on the lower side of the ground detector and the measuring surface on the upper side of the frame detector, the measuring surface on the upper side of the upper vertical plane illumination detector, the photosensitive surface on the lower side of the reflection signal receptor, the luminous surface on the lower side of the signal transmitter, and the photosensitive surface on the lower side of the transmission signal receptor are in the same plane.

[0032] The upper vertical surface illuminance detector is an illuminance collection component with a sampling frequency higher than 100 Hz.

[0033] The left camera, the middle camera, and the right camera are in the same horizontal plane and fixed on the reference horizontal frame. The left camera, the middle camera, and the right camera face the same direction. The left camera, the middle camera, and the right camera have the same external dimensions. The sampling frequency of the left camera, the middle camera, and the right camera is k, and they can be triggered to shoot at the same time. The middle camera is 1.5m above the ground, which is the height of the driver's eyes from the ground set in conventional research. The axes of the left camera, the middle camera, and the right camera are parallel to each other and are in the same plane. The plane formed forms an angle of 1° with the road axis, and the axes of the left camera, the middle camera, and the right camera are horizontally downward compared to the road axis. This is to simulate the situation where the observer's eye height is 1.5m above the road surface, and the line of sight passes through the observer's eyes horizontally downward 1° on the longitudinal vertical plane of the road, that is, at this time, the axes of the left camera, the middle camera, and the right camera respectively pass through the left camera, the middle camera, and the right camera horizontally downward 1° on the longitudinal vertical plane of the road.

[0034] The switch is a circular ring, which can be made of glass and is divided into 8 equal parts by axis symmetry. The transmittance of adjacent parts is different, and the transmittance of separated parts is the same. The transmittance of the part with high transmittance is hn, and the transmittance of the part with low transmittance is ln. The transmittance is quantified by placing different parts of the circular ring between a light source and a standard brightness meter. If the brightness value output by the standard brightness meter remains unchanged before and after placement, the transmittance is recorded as 100%. If the brightness value output by the standard brightness meter after placement is 0, the transmittance is recorded as 0%, that is, the transmittance is the ratio of the brightness value output by the standard brightness meter after placement to the brightness value output by the standard brightness meter before placement.

[0035] Under the control of the switch controller, the switch rotates around the center point of the switch at a speed of v revolutions per second. k≥16v.

[0036] The reference horizontal frame is connected to the support frame, and the support frame is connected to the switch controller. The reference horizontal frame is parallel to the road.

[0037] The central axis of the switch coincides with the central axis of the middle camera, and the inner diameter of the switch is equal to the lens diameter of the middle camera.

[0038] The left and right camera's field of view is blocked by the switch ring.

[0039] The measuring device for the lighting glare of the ETC gantry establishes internal space coordinates. The midpoint of the lens of the middle camera is taken as point O, and the coordinates are (0, 0); the line passing through the midpoint of the lens of the middle camera, the midpoint of the lens of the left camera, and the midpoint of the lens of the right camera is taken as the x-axis, and the direction from the left camera to the right camera is taken as the positive direction; the central axis of the middle camera is taken as the y-axis, and the reference horizontal frame is parallel to the x-axis, and the direction from the middle camera to the switcher is taken as the positive direction.

[0040] The internal spatial coordinates of the positioner are (xd, yd). After each component is installed, its coordinates are obtained by measurement, and the distances between different components are obtained by calculation.

[0041] The technical solution flow chart of the method for measuring the glare of the ETC gantry lighting is as follows: Figure 4 shown.

[0042] The measuring device for the ETC gantry lighting glare is mainly composed of a locator, a data processing module, a reflection signal demodulator, a reflection signal receptor, a transmission signal modulator, a signal transmitter, a transmission signal demodulator, a transmission signal receptor, a transparent and reflective mirror group, a ground-off detector, a frame-off detector, an upper vertical surface illumination detector, a left camera, a middle camera, a right camera, a middle camera light tube, a switcher, a switcher controller, a support frame, a reference horizontal frame and the like.

[0043] The overall technical solution implementation process is as follows:

[0044] (1) It should be clarified that the fill light can refer to the fill light device for the automatic recognition of the highway vehicle license plate video, or it can refer to the fill light device for the traffic technical monitoring imaging, and the threshold increments of the two should be measured and calculated separately. That is, it is necessary to select the corresponding fill light device for measurement, which can be called the selected fill light. When the fill light device for the automatic recognition of the highway vehicle license plate video is selected as the measurement object, the fill light mentioned below refers to the fill light device for the automatic recognition of the highway vehicle license plate video; when the fill light device for the traffic technical monitoring imaging is selected as the measurement object, the fill light mentioned below refers to the fill light device for the traffic technical monitoring imaging.

[0045] (2) The ETC gantry lighting glare measurement device needs to be calibrated before use.

[0046] (3) First, calibrate the illumination. The ETC gantry lighting glare measuring device is stationary at a distance of 13.75m from the front of the ETC gantry. Here, 13.75m simulates the driver's eyes at a height of 1.5m. When the driver is 13.75m away from the ETC gantry, the fill light on the ETC gantry can be observed. The calculation process is as follows: Assume that the height of the observer's eyes is 1.5m above the road surface, the line of sight passes through the observer's eyes horizontally 1° downward on the longitudinal vertical plane of the road, and the vertical distance between the highway vehicle license plate video automatic recognition fill light device and the road surface is 6.5m. Then, it can be calculated that the distance between the observer and the ETC gantry must be greater than 2.75 (6.5-1.5) m, that is, 13.75m. The vertical distance between the traffic technology monitoring imaging fill light device and the road surface is 6m. Then, it can be calculated that the distance between the observer and the ETC gantry must be greater than 2.75 (6-1.5) m, that is, 12.375m. In order to accurately calibrate the illumination, especially the illumination generated by the automatic recognition fill-light device through the highway vehicle license plate video, the ETC gantry lighting glare measuring device is stationary at a distance of 13.75m in front of the ETC gantry.

[0047] (4) Adjust the switcher so that the part of the switcher with low light transmittance is just blocked in front of the left camera and the right camera. Install a light shielding tube in front of the probe of the standard-level illuminance meter. The diameter of the light shielding tube is the same as the diameter of the probe, and the length is 3 times the diameter of the probe. Place the probe and light shielding tube of the standard-level illuminance meter in front of the left camera, and align the light shielding tube with the selected fill light, and measure the reference illuminance value ZSL1. Place the probe and light shielding tube of the standard-level illuminance meter in front of the right camera, and align the light shielding tube with the selected fill light, and measure the reference illuminance value ZSR1. Use the left camera and the right camera to collect the image at this time, and obtain the electrical signal values ​​of all pixels in the selected fill light part of the image as DL1 and DR1 respectively. Adjust the switcher so that the part of the switcher with high light transmittance is just blocked in front of the left camera and the right camera. Place the probe and light shielding tube of the standard-level illuminance meter in front of the left camera, and align the light shielding tube with the selected fill light, and measure the reference illuminance value ZSL2. Place the probe and light shielding tube of the standard-level illuminance meter in front of the right camera, and align the light shielding tube with the selected fill light to measure the reference illuminance value ZSR2. Use the left camera and the right camera to collect the image at this time, and obtain the electrical signal values ​​of all pixels in the selected fill light part of the image as DL2 and DR2 respectively. Calibrate the left camera and the right camera, and record the relationship between the selected fill light illuminance value ZCL collected by the left camera and the electrical signal DLn as follows: when the part in front of the left camera is the part with low transmittance of the switch, ZCL = DLn*ZSL1 / (DL1 / ln); when the part in front of the left camera is the part with high transmittance of the switch, ZCL = DLn*ZSL2 / (DL2 / hn). The relationship between the selected fill light illumination value ZCR collected by the right camera and the electrical signal DRn is recorded as follows: when the part in front of the right camera is the part with low transmittance of the switch, ZCR=DRn*ZSR1 / (DR1 / ln); when the part in front of the right camera is the part with high transmittance of the switch, ZCR=DRn*ZSR2 / (DR2 / hn).

[0048] (5) Then calibrate the position. Use a total station to measure the distance JLS1 between the selected fill light on the front ETC gantry and the middle camera. Use the image data collected by the left camera and the right camera, and use the depth calculation method based on the parallax principle to calculate the distance JLW1 between the selected fill light on the ETC gantry that has not been calibrated and the middle camera. Perform distance calibration, and record the relationship between the calibrated distance measurement result JLYn and the uncalibrated calculation result JLWn as JLYn=JLWn*(JLS1 / JLW1). Use a total station to measure the height LEDh of the selected fill light on the front ETC gantry from the ground, and the lateral deviation LEDw of the selected fill light on the front ETC gantry from the center line of the road. Use the middle camera to collect image data, and extract the number of pixels XSh of the selected fill light from the ground and the number of pixels XSw of the selected fill light from the center line of the road in the image. Coordinate calibration is performed, and the relationship between the calibrated selected fill light height measurement result Lhn and the pixel point number Xhn is recorded as Lhn=Xhn*(LEDh / XSh), and the relationship between the calibrated selected fill light lateral deviation measurement result Lwn from the road centerline and the pixel point number Xwn is recorded as Lwn=Xwn*(LEDw / XSw).

[0049] (6) Recalibrate the brightness. First, use a standard-grade brightness meter to measure the reference brightness value LS of the ground below the ETC gantry. Then move the ETC gantry lighting glare measuring device to the point directly below the ETC gantry. The signal transmitter emits a modulated light beam with a beam energy of p0. m2% of the light passes through the transparent and reflective mirror group, is reflected by the ground below the ETC gantry, is measured by the reflection signal receptor, and is demodulated by the reflection signal demodulator to obtain the reflected light beam energy p20. m1% of the light is reflected by the transparent and reflective mirror group, and then enters the transmission signal receptor, is demodulated by the transmission signal modulator, and obtains the corresponding light beam energy p10. Then p0=p10 / (m1%). The upper vertical plane illuminance detector measures the illuminance value E10, the ground distance detector measures the distance d0 from the ground, and the distance detector measures the distance h0 from the ETC gantry. Then the brightness value LW of the ground below the ETC gantry is p20(E10h0 2 ) / (p10(h0+d0) 2 ). The ground brightness measurement result of the calibrated ETC gantry lighting glare measurement device is obtained as LJ=p20(E10h0 2 ) / (p10(h0+d0) 2 )*LS / LW. That is, in subsequent measurements, the ground brightness measurement result is the actual measurement value LC multiplied by the reference brightness value LS recorded during calibration and then divided by the measurement value LW recorded during calibration.

[0050] (7) When conducting on-site measurement, the measuring device for the ETC gantry lighting glare moves from an area 50m away from the ETC gantry to the ETC gantry. The middle camera is located on a plane perpendicular to the road surface and containing the center line of the road. The switch controller controls the switch to rotate at a speed of v revolutions per second, and the left camera, the middle camera, and the right camera face the direction of the ETC gantry, and simultaneously trigger the capture of images at a sampling frequency k, where k≥16v. Since the switch is axially symmetrically divided into 8 equal parts, the transmittances of adjacent parts are different, and the transmittances of separated parts are the same. The transmittance of the part with high transmittance is hn, and the transmittance of the part with low transmittance is ln. When the switch rotates, when the left camera and the right camera collect images, they can collect images that are simultaneously blocked by the part with high transmittance, and can also collect images that are simultaneously blocked by the part with low transmittance. The image data collected by the left camera and the right camera are used, and the depth calculation method based on the parallax principle is used, combined with calibration, to obtain the distance JLYn of the selected fill light on the ETC gantry from the middle camera. The image data collected by the central camera is combined with calibration to obtain the height measurement result Lhn of the selected fill light and the lateral deviation measurement result Lwn of the selected fill light from the center line of the road. Then the angle formed by the line between the center point of the central camera and the selected fill light and the axis of the central camera is calculated. The comprehensive illumination value ZCZ=(ZCR+ZCL) / 2 is measured using the left camera and the right camera.

[0051] (8) When the ETC gantry lighting glare measuring device passes under the ETC gantry. The signal transmitter emits a modulated light beam with a beam energy of p. m2% of the light passes through the transparent and reflective mirror group, is reflected by the ground under the ETC gantry, is measured by the reflection signal receptor, and is demodulated by the reflection signal demodulator to obtain the reflected light beam energy p2. m2% of the light is reflected by the transparent and reflective mirror group, and then enters the transmission signal receptor, is demodulated by the transmission signal modulator, and obtains the corresponding light beam energy p1. Then p=2*p1. The upper vertical plane illuminance detector measures the illuminance value E1, the ground detector measures the distance d from the ground, and the distance detector measures the distance h from the ETC gantry. The ground brightness measurement result is p2(E1h 2 ) / (p1(h+d) 2 )*LS / LW.

[0052] (9) Calculate the threshold increment of the selected fill light: BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 Hardware connection diagram

[0054] Figure 1In the figure, 1 is a locator, 2 is a data processing module, 3-1 is a reflection signal demodulator, 3-2 is a reflection signal receptor, 4-1 is a transmission signal modulator, 4-2 is a signal transmitter, 5-1 is a transmission signal demodulator, 5-2 is a transmission signal receptor, 6 is a transparent and reflective mirror group, 7 is a ground-lift detector, 8 is a frame-lift detector, 9 is an upper vertical plane illumination detector, 10 is a left camera, 11 is a middle camera, 12 is a right camera, 13 is a middle camera light tube, 14 is a switcher, 15 is a switcher controller, 16 is a support frame, 17 is a reference horizontal frame, S1 is a target road, S2 is an ETC gantry, h is the vertical distance between the frame-lift detector and the ETC gantry, and d is the vertical distance between the ground-lift detector and the ground. The ground described in the present invention is assumed to be a horizontal ground.

[0055] Figure 2 In the figure, 11 is the center camera, 17 is the reference horizontal frame, S1 is the ground, S3 is the axis of the center camera, and β is the angle formed by the axis of the center camera and the ground, which is 1°.

[0056] Figure 3 It is a schematic diagram of the position of the fill light device in the prior art.

[0057] Figure 3 In the figure, S1 is the target road, S2 is the ETC gantry, S4 is the road adjacent to the target road, S9 is the dividing line between the two roads, S5 is the highway vehicle license plate video automatic recognition fill-in light device, S6 is the traffic technology monitoring imaging fill-in light device, S8 is the reference axis of the traffic technology monitoring imaging fill-in light device, and S7 is the center line of the target road. α is the spatial angle between the reference axis of the traffic technology monitoring imaging fill-in light device and the dividing line between the two roads, and its value is 20°.

[0058] Figure 4 Technical solution flow chart

[0059] Figure 5 Technical solution flow chart of specific example 1 DETAILED DESCRIPTION

[0060] The present invention can be used to measure the threshold increment of a highway vehicle license plate video automatic recognition light-filling device and a traffic technology monitoring imaging light-filling device set on an ETC gantry. The process is as follows: Figure 5 .

[0061] Referring to the flowchart of Example 1, the implementation process of the technical solution of Example 1 is as follows:

[0062] (1) Install the ETC gantry lighting glare measurement device on the inspection vehicle. The left camera, center camera, right camera, center camera light tube, switcher, switcher controller, support frame, reference horizontal frame and other parts are installed at the co-pilot position. The positioner, data processing module and other parts are installed inside the inspection vehicle. The reflection signal demodulator, reflection signal receptor, transmission signal modulator, signal transmitter, transmission signal demodulator, transmission signal receptor, transparent and reflective mirror group, ground-lift detector, frame-lift detector, upper vertical illumination detector and other parts are installed on the side of the inspection vehicle.

[0063] (2) Park the inspection vehicle 13.75 meters away from an ETC gantry and use a standard-level illuminance meter and total station to calibrate the illumination and position. If only the threshold increment of the traffic technology monitoring imaging supplementary lighting device on the ETC gantry is considered, the inspection vehicle can also be parked 12.375 meters away from an ETC gantry for illumination and position calibration.

[0064] (3) Park the inspection vehicle directly under the same ETC gantry and use a standard-grade luminance meter to calibrate the brightness.

[0065] (4) Drive the inspection vehicle towards the target ETC gantry and stop only after passing the target ETC gantry. Use the ETC gantry lighting glare measurement device to collect and calculate the corresponding ETC gantry fill light threshold increment formula.

[0066] The present invention realizes the glare measurement of the ETC gantry fill light and realizes the measurement in a dynamic state. When the present invention is used to perform the glare measurement of the ETC gantry fill light, there is no need to block traffic.

[0067] The present invention is easy to operate and can measure the threshold increment, a quantitative evaluation index of glare, using a set of integrated devices. The observation position information, illumination information at the simulated human eye, and ground brightness information required for threshold increment calculation can be obtained using a set of integrated devices.

[0068] The present invention requires a shorter time. Using conventional means to measure the glare of a road lamp, according to statistics, it takes about 30 minutes at the fastest. However, using the present invention to measure the glare of the ETC gantry fill light, according to statistics, it generally only takes 3 minutes.

[0069] The present invention utilizes a locator, a data processing module, a reflection signal demodulator, a reflection signal receptor, a transmission signal modulator, a signal transmitter, a transmission signal demodulator, a transmission signal receptor, a transparent and reflective mirror group, a ground-lift detector, a frame-lift detector, an upper vertical surface illumination detector, a left camera, a middle camera, a right camera, a middle camera light tube, a switcher, a switcher controller, a support frame, a reference horizontal frame and other parts to form a device for measuring the lighting glare of an ETC gantry.

[0070] The present invention proposes a method for measuring the glare of ETC gantry lighting, which measures the reflectivity of the ground below the ETC gantry and the ground brightness, and obtains the calculation formula of the ground brightness p2(E1h 2 ) / (p1(h+d) 2 )*LS / LW, it realizes the acquisition of ground brightness at a close distance, solves the problem of more external stray light interference caused by using brightness meters and other devices to measure brightness at a long distance, and the decrease in the measurement accuracy of brightness meters at a long distance; by obtaining the fill light brightness at different orders of magnitude through switch blades with different light transmittances, it combines the sensitivity advantages of the left camera and the right camera in high brightness areas and low brightness areas, reduces the system error, and obtains a more accurate comprehensive illumination value ZCZ=(ZCR+ZCL) / 2. Using the left camera and the right camera, the distance between the ETC gantry fill light and the middle camera was measured by binocular vision, and the height of the ETC gantry fill light and the lateral deviation from the center line of the road were calculated using the middle camera. Through three geometric parameters, the angle formed by the line between the center point of the middle camera and the fill light and the axis of the middle camera was calculated. The quantitative measurement of the ETC gantry lighting glare was achieved, and the threshold increment formula of the ETC gantry fill light was calculated:

[0071] .3 The present invention uses the on-site ETC gantry for pre-use calibration. There is no need to calibrate in a standard darkroom and geometric measurement laboratory, which improves work efficiency. Since there are no street lights on the highway, the brightness is low at night. Compared with the ETC gantry fill light, other light sources have lower brightness and weaker interference ability, so it is equivalent to treating the site as an open darkroom. When the ETC gantry lighting glare measuring device is stationary at a distance of 13.75m from the front of the ETC gantry, a standard-level illuminance meter is used to obtain a standard illuminance value, and the illuminance measurement capability of the ETC gantry lighting glare measuring device is calibrated; a total station is used to obtain the standard position value of the ETC gantry fill light, and the position measurement capability of the ETC gantry lighting glare measuring device is calibrated. When calibrating the brightness measurement capability of the ETC gantry lighting glare measuring device, first stationary the ETC gantry lighting glare measuring device at a distance of 13.75m from the front of the ETC gantry, use a standard-grade brightness meter to measure the standard value of the ground brightness, then place the ETC gantry lighting glare measuring device under the ETC gantry, use the ETC gantry lighting glare measuring device to collect brightness information, and finally calibrate the brightness measurement capability of the ETC gantry lighting glare measuring device.

Claims

1. A device for measuring glare of ETC gantry lighting, characterized by: It includes a locator, a data processing module, a reflection signal demodulator, a reflection signal receptor, a transmission signal modulator, a signal transmitter, a transmission signal demodulator, a transmission signal receptor, a transparent and reflective mirror group, a ground-off detector, a frame-off detector, an upper vertical illumination detector, a left camera, a middle camera, a right camera, a middle camera light tube, a switcher, a switcher controller, a support frame, and a reference horizontal frame; The locator is a positioning device based on a GPS receiving module, or a positioning device based on a BDS receiving module; The data processing module is a computer, an industrial computer or a single-chip microcomputer, which collects data output by the locator, the reflection signal demodulator, the transmission signal modulator, the ground-off detector, the frame-off detector, the upper vertical illumination detector, the left camera, the middle camera and the right camera through wired or wireless means, and controls the transmission signal demodulator and the switch controller; The reflected signal demodulator is a signal demodulation circuit that demodulates the signal output by the reflected signal receptor, and the demodulation method corresponds to the modulation method; The transmitting signal modulator is a signal modulation circuit, which controls the signal transmitter to emit a modulated optical signal; The transmission signal demodulator is a signal demodulation circuit that demodulates the signal output by the transmission signal receptor, and the demodulation method corresponds to the modulation method; The signal transmitter is the component that emits the light signal; The transmissive and reflective mirror set is composed of a set of lenses with a reflectivity of m1% and a transmittance of m2% and a corresponding bracket, and m1+m2=100; The central axis of the light beam emitted by the signal transmitter passes through the center point of the transparent and reflective mirror group; the energy of the light beam emitted by the signal transmitter is p, and the m2% part passes through the transparent and reflective mirror group, is reflected by the ground, and then enters the reflection signal receptor, and is demodulated by the reflection signal demodulator to obtain the energy p2 of the reflected light; the m1% part of the light beam emitted by the signal transmitter is reflected by the transparent and reflective mirror group, enters the transmission signal receptor, and is demodulated by the transmission signal demodulator to obtain the felt light beam energy p1; The ground clearance detector is a component that measures the vertical distance from the ground; The off-frame detector is a device for measuring the lighting glare of the ETC gantry. When passing under the ETC gantry, it measures the vertical distance from the ETC gantry. It is a laser distance measurement module or an ultrasonic distance measurement module. The measuring surface on the lower side of the ground detector and the measuring surface on the upper side of the frame detector, the measuring surface on the upper side of the vertical illumination detector, the photosensitive surface on the lower side of the reflection signal receptor, the luminous surface on the lower side of the signal transmitter, and the photosensitive surface on the lower side of the transmission signal receptor are in the same plane; The upper vertical surface illuminance detector is an illuminance collection component with a sampling frequency higher than 100Hz; The left camera, the middle camera, and the right camera are in the same horizontal plane and fixed on the reference horizontal frame. The left camera, the middle camera, and the right camera face the same direction. The left camera, the middle camera, and the right camera have the same external dimensions. The sampling frequency of the left camera, the middle camera, and the right camera is k, and they can be triggered to shoot at the same time. The middle camera is 1.5m away from the ground. The axes of the left camera, the middle camera, and the right camera are parallel to each other and in the same plane. The formed plane forms an angle of 1° with the road axis, and the axes of the left camera, the middle camera, and the right camera are horizontally downward compared to the road axis. The switch is a circular ring, which is axially symmetrically divided into 8 equal parts. The transmittances of adjacent parts are different, and the transmittances of separated parts are the same. The transmittance of the part with high transmittance is hn, and the transmittance of the part with low transmittance is ln. Under the control of the switch controller, the switch rotates around the center point of the switch at a speed of v revolutions per second; k ≥ 16v; The reference horizontal frame is connected to the support frame, and the support frame is connected to the switch controller; the reference horizontal frame is parallel to the road; The central axis of the switch coincides with the central axis of the central camera; the inner diameter of the switch is equal to the lens diameter of the central camera; The left and right camera's field of view is blocked by the switch ring.

2. A method for applying the device of claim 1, characterized in that: The measuring device for the ETC gantry lighting glare establishes internal space coordinates; the midpoint of the middle camera lens is taken as point O, and the coordinates are (0, 0); the line passing through the midpoint of the middle camera lens, the midpoint of the left camera lens, and the midpoint of the right camera lens is taken as the x-axis, and the direction from the left camera to the right camera is taken as the positive direction; the central axis of the middle camera is taken as the y-axis, the reference horizontal frame is parallel to the x-axis, and the direction from the middle camera to the switch is taken as the positive direction; The internal spatial coordinates of the positioner are (xd, yd); after each component is installed, its coordinates are obtained by measurement, and the distances between different components are obtained by calculation; The implementation process is as follows: (1) Fill-in light refers to a highway vehicle license plate video automatic recognition fill-in light device, or refers to a traffic technical monitoring imaging fill-in light device, and the threshold increments of the two shall be measured and calculated separately; that is, it is necessary to select the corresponding fill-in light device for measurement, which can be called the selected fill-in light; when the highway vehicle license plate video automatic recognition fill-in light device is selected as the measurement object, the fill-in light mentioned below refers to the highway vehicle license plate video automatic recognition fill-in light device; when the traffic technical monitoring imaging fill-in light device is selected as the measurement object, the fill-in light mentioned below refers to the traffic technical monitoring imaging fill-in light device; (2) The ETC gantry lighting glare measurement device needs to be calibrated before use; (3) First, calibrate the illumination; place the ETC gantry lighting glare measuring device at a distance of 13.75 m from the front of the ETC gantry; (4) Adjust the switch so that the part of the switch with low light transmittance is just blocked in front of the left camera and the right camera; install a light shielding tube in front of the probe of the standard-level illuminance meter, the diameter of the light shielding tube is the same as the diameter of the probe, and the length is 3 times the diameter of the probe; place the probe and light shielding tube of the standard-level illuminance meter in front of the left camera, and align the light shielding tube with the selected fill light, and measure to obtain the reference illuminance value ZSL1; place the probe and light shielding tube of the standard-level illuminance meter in front of the right camera, and align the light shielding tube with the selected fill light, and measure to obtain the reference illuminance value ZSR1; use the left camera and the right camera to respectively capture the image at this time, and obtain the electrical signal values ​​of all pixels in the selected fill light part of the image, which are DL1 and DR1 respectively; adjust the switch so that the part of the switch with high light transmittance is just blocked in front of the left camera and the right camera; place the probe and light shielding tube of the standard-level illuminance meter in front of the left camera, and align the light shielding tube with the selected fill light, and measure to obtain the reference illuminance value ZSL2; place the probe and light shielding tube of the standard-level illuminance meter in front of the left camera In front of the right camera, and align the light shielding tube with the selected fill light, measure the reference illumination value ZSR2; use the left camera and the right camera to collect the image at this time, respectively, and obtain the electrical signal values ​​of all pixels of the selected fill light part in the image, which are DL2 and DR2 respectively; calibrate the left camera and the right camera, and record the relationship between the selected fill light illumination value ZCL collected by the left camera and the electrical signal DLn as follows: when the left camera is in front of the part with low transmittance of the switch, ZCL=DLn*ZSL1 / (DL1 / ln); when the left camera is in front of the part with high transmittance of the switch, ZCL=DLn*ZSL2 / (DL2 / hn); record the relationship between the selected fill light illumination value ZCR collected by the right camera and the electrical signal DRn as follows: when the right camera is in front of the part with low transmittance of the switch, ZCR=DRn*ZSR1 / (DR1 / ln); when the right camera is in front of the part with high transmittance of the switch, ZCR=DRn*ZSR2 / (DR2 / hn); (5) Then calibrate the position; use the total station to measure the distance JLS1 of the camera in the selected fill light distance on the front ETC gantry; use the image data collected by the left camera and the right camera to obtain the distance JLW1 of the camera in the selected fill light distance on the ETC gantry that has not been calibrated measured by the ETC gantry lighting glare measurement device; Perform distance calibration, and record the relationship between the calibrated distance measurement result JLYn and the uncalibrated calculation result JLWn as JLYn=JLWn*(JLS1 / JLW1); use the total station to measure the height LEDh of the selected fill light on the front ETC gantry from the ground, and the lateral deviation LEDw of the selected fill light on the front ETC gantry from the center line of the road; use the central camera to collect image data, and extract the number of pixels XSh of the selected fill light from the ground and the number of pixels XSw of the selected fill light from the center line of the road in the image; perform coordinate calibration, and record the relationship between the calibrated selected fill light height measurement result Lhn and the number of pixels Xhn as Lhn=Xhn*(LEDh / XSh), and record the relationship between the calibrated selected fill light from the center line of the road The lateral deviation measurement result Lwn and the number of pixels Xwn is recorded as Lwn=Xwn*(LEDw / XSw); (6) Recalibrate the brightness; first use a standard brightness meter to measure the reference brightness value LS of the ground below the ETC gantry; Then, the ETC gantry lighting glare measuring device is moved to the bottom of the ETC gantry, and the signal transmitter emits a modulated light beam with a light beam energy of p0, m2%. The light passes through the transparent and reflective mirror group, is reflected by the ground below the ETC gantry, is measured by the reflection signal receptor, and is demodulated by the reflection signal demodulator to obtain the reflected light beam energy p20; m1% of the light is reflected by the transmissive and reflective mirror group, and then enters the transmission signal receptor, and is demodulated by the transmission signal modulator to obtain the corresponding light beam energy p10; then p0 = p10 / (m1%); The vertical illumination detector measures the illumination value E10, the ground detector measures the distance from the ground d0, and the frame detector measures the distance from the ETC gantry h0. The brightness value LW of the ground below the ETC gantry is p20 (E10h0 2 ) / (p10(h0+d0) 2 );Get the calibrated ETC gantry lighting glare measurement device ground brightness measurement result LJ=p20(E10h0 2 ) / (p10(h0+d0) 2 )*LS / LW; that is, in subsequent measurements, the ground brightness measurement result is the actual measurement value LC multiplied by the reference brightness value LS recorded during calibration and then divided by the measurement value LW recorded during calibration; (7) When conducting on-site measurement, the ETC gantry lighting glare measuring device is moved from an area 50 m away from the ETC gantry to the ETC gantry; The middle camera is located on a plane perpendicular to the road surface and including the center line of the road; the switch controller controls the switch to rotate at a speed of v revolutions per second, and the left camera, the middle camera, and the right camera face the direction of the ETC gantry, and are triggered to shoot and collect images at the same time with a sampling frequency of k, where k ≥ 16v; since the switch is axially symmetrically divided into 8 equal parts, the transmittance of adjacent parts is different, and the transmittance of separated parts is the same, the transmittance of the part with high transmittance is hn, and the transmittance of the part with low transmittance is ln. When the switch rotates, the left camera and the right camera collect images and can collect The image blocked by the part with high light transmittance can also be captured at the same time as the image blocked by the part with low light transmittance; the image data collected by the left camera and the right camera are used to obtain the distance JLYn between the selected fill light on the ETC gantry and the middle camera; the image data collected by the middle camera is combined with the calibration to obtain the height measurement result Lhn of the selected fill light and the lateral deviation measurement result Lwn of the selected fill light from the center line of the road; the angle formed by the line between the center point of the middle camera and the selected fill light and the axis of the middle camera is calculated The left camera and the right camera are used to measure the comprehensive illumination value ZCZ = (ZCR + ZCL) / 2; (8) When the ETC gantry lighting glare measuring device passes under the ETC gantry, the signal transmitter emits a modulated light beam with a light beam energy of p,m2% passing through the transparent and reflective mirror group, reflected by the ground under the ETC gantry, measured by the reflection signal receptor, and demodulated by the reflection signal demodulator to obtain the reflected light beam energy p2; m2% of the light is reflected by the transparent and reflective mirror group, and then enters the transmitting signal receptor, and is demodulated by the transmitting signal modulator to obtain the corresponding light beam energy p1; then p = 2*p1; the upper vertical plane illumination detector measures the illumination value E1, the ground detector measures the distance d from the ground, and the frame detector measures the distance h from the ETC gantry, then the ground brightness measurement result is p2(E1h 2 ) / (p1(h+d) 2 )*LS / LW; (9) Calculate the threshold increment of the selected fill light:

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