Light shielding performance test method and device

Abstract

The invention provides a light shielding performance test method, which measures the light shielding performance of a tested vehicle by using an excitation light source, a diffusion screen and an imaging measurement unit, and comprises the following specific measurement steps: S1, turning on the excitation light source, setting the light of the tested vehicle to a tested mode, and enabling the tested vehicle to run according to set requirements; s2, in the driving process of the measured vehicle, acquiring two or more groups of light spot images on the diffusion screen by using an imaging measurement unit; s3, analyzing the light spot image by using a data processing and analyzing unit to obtain light space light distribution data of the tested vehicle; and S4, analyzing the spatial light distribution data to obtain light shielding information of the tested vehicle corresponding to the dark area of the diffusion screen. According to the invention, the problems of low measurement resolution, incapability of comprehensively evaluating the shielding performance and the like in the shielding performance test of the automobile headlamp in the prior art are effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of light shielding performance testing, and particularly relates to a method and device for testing light shielding performance. Background Art

[0002] In recent years, with the development of technologies such as machine vision, matrix automotive headlamp array light source modules, and multi-modal interaction sensors, automotive intelligent headlamps, such as Adaptive Driving Beam (ADB) systems, have emerged to meet the needs of people for intelligent driving lighting functions.

[0003] The ADB system can automatically adjust the light distribution (such as the illumination range and brightness) of intelligent headlamps according to different road conditions and driving conditions. Specifically, during following or oncoming vehicle encounters, it can detect the vehicle ahead or oncoming vehicle in real time through a camera or sensor, and automatically adjust the beam intensity and light-emitting area to precisely shield the light directly hitting other vehicles, that is, form a shielding area to avoid dazzling the driver, while maintaining the high-beam illumination in other areas. While ensuring the driver's own field of vision, it minimizes interference to other road users to the greatest extent and reduces the risk of traffic accidents caused by glare, thereby improving driving safety. However, if there are problems such as too slow excitation speed and too wide shielding area during driving, it will seriously affect driving safety and thus generate new safety hazards and risks. Therefore, it is very necessary to measure the shielding performance of the vehicle's intelligent headlamps.

[0004] In the prior art, the measurement of the shielding performance of vehicle intelligent headlamps mainly relies on arranging illuminance meters at the positions of the oncoming vehicle driver, the interior and exterior rearview mirrors of the same-direction vehicle, and on the lane. This measurement method judges the shielding situation of the tested vehicle's light by the change in single-point illuminance. It is easy to implement and relatively simple to operate, but has low measurement resolution, and the method of measuring the single-point illuminance value is easily affected by the ground flatness and vehicle state, with poor repeatability. At the same time, the information obtained by this measurement method is limited, and it can provide less improvement information about the vehicle lamp to the user. Especially for current high-resolution intelligent headlamps such as ADB and Digital Light Processing (DLP), which can integrate tens of thousands of pixels, only with comprehensive enough information can more accurate shielding performance be better achieved.

[0005] In order to improve the measurement accuracy, there are also technical solutions that propose to use a combination of a transmissive projection screen and a camera to collect the projected area of the excitation vehicle on the projection screen for shielding performance evaluation. This solution improves the measurement resolution, but it cannot well distinguish the situation where the shielding area is smaller than the vehicle body.

[0006] In view of the problems of low accuracy, incomplete information and blind spots in the evaluation of shielding performance in the existing ADB shielding performance test methods, it is urgent to provide a fast and efficient method and device for testing the lighting shielding performance. Summary of the Invention

[0007] Aiming at the deficiencies of the prior art, the present invention provides a method and a test device for testing the lighting shielding performance, aiming to solve the problems of low measurement accuracy, less effective information obtained, and inability to comprehensively evaluate the shielding performance in the existing test of the shielding performance of intelligent vehicle headlights.

[0008] To achieve the above technical objectives, the present invention provides a method for testing the lighting shielding performance, which uses an excitation light source, a diffuser screen and an imaging measurement unit to measure the lighting shielding performance of the vehicle to be tested. The diffuser screen is arranged between the excitation light source and the vehicle to be tested, and the diffusing surface faces the vehicle to be tested. An light outlet hole is opened on the diffuser screen, and the light beam of the excitation light source is emitted from the light outlet hole of the diffuser screen. The imaging measurement unit is aligned with the diffuser screen and obtains the light spot formed on the diffuser screen by the lighting of the vehicle to be tested. The data processing and analysis unit analyzes the light spot image, so as to obtain the lighting shielding information of the vehicle to be tested. The specific measurement steps include:

[0009] S1: Turn on the excitation light source, set the lighting of the vehicle to be tested to the tested mode, and make the vehicle to be tested drive according to the set requirements;

[0010] S2: During the driving process of the vehicle to be tested, use the imaging measurement unit to obtain two or more light spot images on the diffuser screen;

[0011] S3: Use the data processing and analysis unit to analyze the light spot image to obtain the spatial light distribution data of the lighting of the vehicle to be tested;

[0012] S4: Analyze the spatial light distribution data to obtain the lighting shielding information of the vehicle to be tested corresponding to the dark area of the diffuser screen.

[0013] Among them, the shielding information in step S4 includes but is not limited to the width, height, position information of the shielding area and the illuminance distribution within the shielding area. The shielding area is the dark area formed on the diffuser screen when the lighting of the vehicle to be tested automatically reduces or switches part of the light to avoid glare interference to the opposite side.

[0014] In the above technical solution, an imaging measurement unit is used to obtain the light spot formed by the vehicle's light on the diffuser screen. Compared with the traditional method of using an illuminance probe array to obtain illuminance data, the measurement resolution of the present invention is high, and the effective information obtained is more comprehensive, which helps users better analyze and improve the design of the vehicle's headlights to be measured. Compared with the method of combining a transmissive screen and a camera, the present invention uses a diffuser screen to effectively avoid the light homogenization effect caused by light penetration of the transmissive screen. Through the principle of diffuse reflection, the light spot formed by the vehicle's light on the diffuser screen more truly restores the light distribution characteristics. Especially at the bright-dark boundary of the shielding area, it can accurately present the details of light attenuation, avoid measurement errors caused by light homogenization, make key data such as the shielding range and illuminance distribution closer to the actual situation, and make the measurement more accurate; compared with the transmissive screen, the diffuser screen also has the advantages of high measurement efficiency and easy maintenance. In addition, the design of the light-emitting holes on the diffuser screen innovatively solves the problem that it is difficult to measure when the shielding area in the prior art using the transmissive screen and camera measurement technology is smaller than the width of the vehicle body being excited; the size of the light-emitting holes matches the size of the excitation light source, effectively reducing the interference of the excitation light source light and the measurement blind area. The technical solution of the present invention is applicable to the testing of various vehicle types and can achieve fast, efficient and accurate measurement.

[0015] As a technical solution, in step S2, while the imaging measurement unit obtains the light spot image, the corresponding relationship between the current light spot image and the distance between the vehicle to be measured and the diffuser screen is obtained by means of synchronous communication, so as to obtain the shielding state of the vehicle to be measured during the entire driving process. Through the distance between the vehicle to be measured and the diffuser screen, combined with information such as the shape, size and light intensity distribution of the light spot image, the light shielding information of the vehicle to be measured at different positions can be accurately obtained. During the driving process of the vehicle to be measured, two or more light spot images are obtained by using the imaging measurement unit. The imaging measurement unit can obtain the light spot image in real time or obtain the light spot image by means of signal triggering; then the data processing and analysis unit processes and analyzes to obtain the light shielding information of the vehicle to be measured at different positions, without complex operation procedures and long preparation work, greatly improving the test efficiency.

[0016] In a technical solution, a GPS positioning system is installed on the vehicle to be measured; the imaging measurement unit is triggered to take pictures through GPS signals; the distance between the vehicle to be measured and the diffuser screen is correlated with the light spot image obtained by the imaging measurement unit in the GPS time dimension. This technical solution uses the GPS positioning system to associate the shooting trigger of the imaging measurement unit with the real-time position of the vehicle. During the driving process of the vehicle to be measured, each light spot image is accurately associated with the coordinate position information of the vehicle to be measured at that time. Based on the accurate association of the distance and the light spot image, the light shielding range distribution and shielding information of the vehicle to be measured at different positions can be obtained.

[0017] In another technical solution, it further includes a control unit and infrared sensors respectively arranged at one or more specified positions away from the diffuser screen. The infrared sensors and the imaging measurement unit are respectively communicatively connected to the control unit. When the vehicle to be measured travels to the specified distance, the control unit reads the signal triggered by the infrared sensor and simultaneously triggers the imaging measurement unit to perform measurement, so as to obtain the spot image on the diffuser screen at the specified distance, or the imaging measurement unit can also collect the spot image on the diffuser screen in real time. Based on the time when the control unit reads the signal triggered by the infrared sensor, the distance between the vehicle to be measured and the diffuser screen is corresponded to the spot image obtained by the imaging measurement unit, and then the light shielding range distribution and shielding information of the vehicle to be measured at different positions are obtained. The infrared sensor is an infrared opposed switch or an infrared reflective switch.

[0018] In yet another technical solution, it further includes a laser rangefinder and a control unit. The laser rangefinder and the imaging measurement unit are respectively communicatively connected to the control unit. When the laser rangefinder measures that the vehicle to be measured travels to the specified distance, the control unit triggers the imaging measurement unit to perform measurement, so as to obtain the spot image on the diffuser screen at the specified distance, or the imaging measurement unit can also collect the spot image on the diffuser screen in real time. The control unit reads the distance information transmitted by the laser rangefinder at different times in real time. Based on the ranging time of the laser rangefinder read by the control unit, the distance between the vehicle to be measured and the diffuser screen is corresponded to the spot image obtained by the imaging measurement unit, and then the light shielding range distribution and shielding information of the vehicle to be measured at different positions are obtained.

[0019] Further, the laser rangefinder can be fixedly installed in front of the vehicle to be measured and move together with the vehicle to be measured. The laser rangefinder is used to measure the distance between the vehicle to be measured and the diffuser screen; or the laser rangefinder is fixedly installed at one or more specified positions away from the diffuser screen, and the laser rangefinder is used to measure the distance between the vehicle to be measured and the laser rangefinder.

[0020] As a technical solution, the light shielding performance test of the vehicle to be measured includes the test scenarios of oncoming meeting and following in the same direction. When the test scenario is oncoming meeting, the vehicle to be measured and the excitation light source are arranged in adjacent lanes. The excitation light source is a headlamp or a lamp simulating a headlamp or a headlamp installed on the whole vehicle. When the test scenario is following in the same direction, the vehicle to be measured and the excitation light source are arranged in the same lane. The excitation light source is a rear position lamp or a lamp simulating a rear position lamp or a rear position lamp installed on the whole vehicle.

[0021] As a technical solution, the imaging measurement unit is located between the vehicle under test and the standard excitation vehicle and is arranged facing the diffuser screen; its field of view angle should cover the diffuser screen (within at least three lanes) and its position should ensure that it does not block the outgoing light of the headlamp of the vehicle under test and the outgoing light of the excitation light source.

[0022] As a technical solution, step S3 also includes performing noise removal, image correction, position relationship calibration, and contour recognition processing on the obtained spot image. Through noise removal processing, interference signals such as noise can be effectively removed, making the spot image clearer. For example, by using common noise removal algorithms such as mean filtering and median filtering, the noise points in the image can be smoothed, highlighting the true contour and internal light intensity distribution of the spot. The image after noise removal provides a more accurate data basis for subsequent position relationship calibration and contour recognition, avoiding misjudgment of the spot position and shape caused by noise interference, thereby improving the accuracy of the final analysis of the light shielding information.

[0023] Generally, there will be a certain angular relationship between the detection surface of the imaging measurement unit and the diffuser screen plane, and the spot image obtained on the diffuser screen will change due to the perspective characteristics. Therefore, it is necessary to correct the obtained image to ensure the accuracy of the test results. When the field of view of the imaging measurement unit covers the diffuser screen and the diffuser screen is rectangular, the specific steps include:

[0024] A1: By performing corner point recognition on the obtained image, obtain the pixel coordinates (x, y) of the four corner points of the diffuser screen in the source image;

[0025] A2: Use measurement methods to obtain the actual width and height of the diffuser screen, obtain the actual aspect ratio of the diffuser screen, and combine the angle of the trapezoid in the source image and the actual aspect ratio of the diffuser screen to calculate the pixel coordinates (x’, y’) of the four target angles

[0026] A3: Calculate the perspective transformation matrix M based on the trapezoid corner point coordinates of the source image and the rectangular corner point coordinates of the target image obtained in steps A1 and A2;

[0027]

[0028] A4: Apply the perspective transformation matrix to the coordinate mapping:

[0029]

[0030] where is the normalized target coordinate.

[0031] Further, when the perspective of the imaging measurement unit cannot fully cover the diffuser screen or the diffuser screen is not an ideal rectangle, four fiducial points can also be set on the diffuser screen to form a rectangle or a specific pattern; or a rectangular light spot or a specific pattern can be projected onto the diffuser screen, and then the above steps A1 - A3 are used for image correction.

[0032] Further, during the above image correction process, based on the measured size of the diffuser screen and information such as the installation angle of the imaging measurement unit, the distance between the imaging measurement unit and the diffuser screen, the emission angle of the light source projecting the specific pattern, and the size of the projected pattern, the correspondence between the pixels of the imaging measurement unit and the spatial position of the diffuser screen can be further calibrated.

[0033] The calibration of the position relationship specifically includes: calibrating the correspondence between the pixels of the imaging measurement unit and the spatial position of the diffuser screen through the spatial geometric position relationship; or using a light source with a known emission angle and clear contour at a specified position to calibrate the correspondence between the pixels of the imaging measurement unit and the spatial position of the diffuser screen; or combining the above two methods to calibrate the correspondence between the pixels of the imaging measurement unit and the spatial position of the diffuser screen. Through the calibration of the position relationship, the relative position between the occlusion range and the excitation light source, as well as the actual width and height of the occlusion area, can be obtained. At the same time, all the light spot images can be unified into a standard coordinate system. When analyzing the occlusion situation of the vehicle's lights at different driving positions, the position changes between different light spot images can be accurately compared, and the dynamic changes in the occlusion performance of the vehicle's lights during driving can be more comprehensively understood.

[0034] Through contour recognition processing, the boundary of the light spot can be accurately outlined, and the range of the light spot can be determined. The contour of the light spot contains rich information, such as the irradiation angle of the light and the boundary of the intensity distribution. Through advanced contour recognition algorithms, such as the edge detection algorithm (Canny algorithm, etc.), the contour line of the light spot can be clearly extracted. An accurate light spot contour can more precisely calculate the size, shape, and position of the occlusion area, providing key data support for evaluating the occlusion performance of the vehicle's lights.

[0035] As a technical solution, it also includes calibrating the response of the imaging measurement unit using a standard light source with a known light intensity distribution. The light emitted by the standard light source irradiates the diffuser screen, and the imaging measurement unit aligns with the light spot formed by the standard light source on the diffuser screen. Each point in the diffuser screen light spot corresponds to the pixels of the array detector in the imaging measurement unit. Since the spatial light intensity distribution of the standard light source is known, the response values of each pixel in the imaging measurement unit are calibrated; using the calibrated imaging measurement unit to measure and analyze the spatial light intensity or illuminance data of the vehicle's lights to be measured, the obtained measurement results are more accurate.

[0036] In a specific embodiment, the light intensity and illuminance data on the diffuser screen obtained are analyzed to obtain the shielding information of the lights of the vehicle under test, which specifically includes:

[0037] B1: Perform filtering and noise reduction processing on the obtained light intensity / illuminance data to obtain data D f ;

[0038] B2: Perform enhancement and threshold segmentation on data D f to obtain the shielding area and the excitation light source area;

[0039] B3: Calculate the position, width W, height H, and area of the shielding area in combination with the relative positions of the shielding area and the excitation light source, where the area of the shielding width is W×H.

[0040] As a technical solution, it further includes using the spatial light intensity or illuminance data of the vehicle under test at different distances obtained to analyze the illuminance information at the driver's glare point when there is an oncoming vehicle or at the rearview mirror when following a vehicle, and the road surface illuminance information of other lanes after conversion, so as to further obtain the glare and visibility information of the lights of the vehicle under test. Taking a four-wheeled vehicle as an example, the driver's glare point when there is an oncoming vehicle is generally located at a position 0.15 meters to the left of the longitudinal axis of the excitation light source and at a height of 1.1 meters (for a sedan) or 2.2 meters (for a truck); the positions of the rearview mirrors when following a vehicle include the interior rearview mirror and the exterior rearview mirror. The interior rearview mirror is generally at a position 1.2 meters above the longitudinal axis of the excitation light source, and the exterior rearview mirror is generally at positions 0.9 meters to the left and right of the longitudinal axis of the excitation light source respectively and at a height of 0.9 meters (for a sedan) or 1.8 meters (for a truck); the glare performance of the lights of the vehicle under test can be evaluated by analyzing whether the illuminance values at the above positions exceed the glare requirements. The visibility is generally evaluated by the exposure distance at which the illuminance reaches 5 lux at a height of 0.25 meters from the ground.

[0041] As a technical solution, the excitation light source is initially in the off state. When the vehicle under test travels to a specified distance, the excitation light source is turned on. By combining the time when the excitation light source is turned on and the time when the spatial light intensity or illuminance data on the diffuser screen changes significantly, it is further determined whether the lights of the vehicle under test are excited and the response time information of the vehicle under test.

[0042] In the above technical solution, the diffuser screen is arranged perpendicular to the horizontal plane, and the size of the diffuser screen covers the beam area projected by the lights of the vehicle under test. The diffuser screen can be composed of multiple diffuser screens spliced together or a single diffuser screen.

[0043] As a technical solution, two light output holes are provided on the diffuser screen, corresponding to the left and right lights respectively, to ensure that the excitation light source is not blocked and can effectively excite the headlamps of the vehicle under test.

[0044] Further, in the above technical solution, in order to expand the versatility of the system, the diameter, shape, and position of the light outlet hole are all adjustable to adapt to excitation light sources of different models and specifications, so that the light emitted from the headlamp of the vehicle to be tested is not blocked by other positions except the excitation light source, and is projected onto the diffuser screen as completely as possible, ensuring the integrity of the test data, ensuring that the case where the shielding area is smaller than the vehicle width can be effectively detected, avoiding misjudgment of the shielding area due to light loss, and improving the test accuracy.

[0045] The present invention also provides a test device for testing the light shielding performance, including an excitation light source, a diffuser screen, an imaging measurement unit, and a data processing and analysis unit; the diffuser screen is arranged between the excitation light source and the vehicle to be tested, and the diffusing surface faces the vehicle to be tested. An outlet hole is provided on the diffuser screen, and the size of the outlet hole matches the size of the light-emitting surface of the excitation light source. The imaging measurement unit is arranged on one side of the vehicle to be tested and aligned with the diffuser screen for obtaining a spot image formed by the light of the vehicle to be tested on the diffuser screen, and the data processing and analysis unit analyzes the spot image to obtain the light shielding information of the vehicle to be tested.

[0046] Further, it further includes a ranging device for measuring the perpendicular distance between the vehicle to be tested and the diffuser screen. The ranging device is a GPS positioning system or a laser rangefinder or an infrared sensor or a camera or a lidar or a millimeter-wave radar installed on the vehicle to be tested. The path information of the vehicle to be tested is obtained by using the ranging device, so as to obtain the light shielding information at a specific distance. Taking the positioning method using the GPS positioning system as an example, specifically: a GPS positioning system is installed on the vehicle to be tested, and the vehicle to be tested travels according to the set requirements to obtain distance data with corresponding GPS time; the device also includes a GPS time synchronization module. When the vehicle starts to travel, the GPS time synchronization module triggers the imaging measurement unit to start sampling synchronously at a fixed frequency, thereby obtaining the shielding information with GPS time; by comparing the GPS time, the shielding information is corresponded to the distance between the vehicle and the diffuser screen one by one to obtain the light shielding information of the vehicle to be tested at different distances.

[0047] In the above technical solution, the diffuser screen is arranged perpendicular to the horizontal plane, and the size of the diffuser screen covers the beam area projected by the light of the vehicle to be tested, and the diffuser screen generally covers at least 3 lanes.

[0048] As a technical solution, two light-emitting holes with adjustable diameters, shapes, and positions are provided on the diffuser screen. The size of the light-emitting holes can be flexibly adjusted to adapt to excitation light sources of different models and specifications, expanding the versatility of the test system. At the same time, it ensures that the excitation light source is not blocked, and can effectively excite the headlamp of the vehicle under test. At the same time, since the diffuser screen is arranged between the vehicle under test and the excitation light source, and the aperture of the light-emitting hole can effectively adapt to the size of the excitation light source, the light emitted by the headlamp of the vehicle under test is not blocked by the excitation light source (or the excitation vehicle), and is projected onto the diffuser screen as completely as possible, ensuring the integrity of the test data, ensuring that the case where the shielding area is smaller than the vehicle width can be effectively detected, avoiding misjudgment of the shielding area due to lack of light, and improving the test accuracy.

[0049] The beneficial effects of the present invention. The present invention provides a method and device for testing the light shielding performance. Through the design of the light-emitting holes on the diffuser screen that match the excitation light source, the imaging measurement unit quickly and clearly obtains the spot image of the adaptive high beam of the vehicle under test on the diffuser screen, thereby realizing the accurate identification of the shielding area of the vehicle, and effectively solving the problems of low measurement resolution and inability to comprehensively evaluate the shielding performance in the existing test of the light shielding performance of automotive headlamps. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] FIG Figure 1 is a schematic structural diagram of a device for testing the light shielding performance provided in Embodiment 1;

[0051] FIG Figure 2 、FIG Figure 3 and FIG Figure 4 are respectively schematic diagrams of the shielding area provided in Embodiment 1;

[0052] FIG Figure 5 is a distance-illuminance curve graph in Embodiment 1;

[0053] FIG Figure 6 is a schematic structural diagram of a device for testing the light shielding performance provided in Embodiment 2;

[0054] FIG Figure 7 is a schematic structural diagram of a device for testing the light shielding performance provided in Embodiment 3;

[0055] In the figure: 1 - excitation light source, 2 - diffuser screen, 3 - imaging measurement unit, 4 - vehicle under test, 5 - light-emitting hole, 6 - shielding area, 7 - data processing and analysis unit. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0056] Embodiment 1

[0057] This embodiment provides a device for testing the light shielding performance, as shown in Figure 1As shown in the figure, it includes the vehicle under test 4, the excitation light source 1, the imaging measurement unit 3, the diffuser screen 2, and the data processing and analysis unit 7; the vehicle under test 4 and the excitation vehicle are in the same lane, and a GPS positioning system is installed on the vehicle under test 4. The excitation light source 1 is the rear position light system installed on the excitation vehicle. The data processing and analysis unit 7 includes a GPS time synchronization module, and the GPS time synchronization module is communicatively connected to the imaging measurement unit 3. The diffuser screen 2 is arranged at a position 10 cm away from the excitation light source 1 between the excitation light source 1 and the vehicle under test 4, and the diffusing surface faces the vehicle under test 4. Two light output holes 5 adapted to the position and size of the excitation light source 1 are opened on the diffuser screen 2. During the driving of the vehicle under test, the GPS time synchronization module triggers the imaging measurement unit to collect the spot images containing the shielding area on the diffuser screen at a certain frequency, and the data processing and analysis unit is used to analyze the spot images to obtain the light shielding information of the vehicle under test.

[0058] This embodiment also provides a method for testing the light shielding performance. Taking following the same lane as an example, the vehicle under test and the excitation vehicle are in the same lane. A vehicle-mounted GPS positioning system is installed on the vehicle under test. The imaging measurement unit is placed at a certain angle facing the diffusing surface of the diffuser screen. The width of the diffuser screen covers three lanes, and the height is not less than the height of the excitation vehicle, generally 2 meters. The initial distance between the vehicle under test and the excitation vehicle is generally greater than 200 m, and the driving speed is not less than 60 km / h. The light shielding performance measurement of the vehicle under test is carried out according to the following specific steps:

[0059] C1: Calibrate the response of the imaging measurement unit using a standard light source with a known light intensity distribution. The light emitted by the standard light source is irradiated onto the diffuser screen, and the imaging measurement unit is aligned to measure the spot formed by the standard light source on the diffuser screen. Each point in the spot on the diffuser screen corresponds to the pixel of the array detector in the imaging measurement unit. Since the spatial light intensity distribution of the standard light source is known, the response values of each pixel in the imaging measurement unit are calibrated; subsequently, the calibrated imaging measurement unit is used to measure the spatial light intensity or illuminance data of the light of the vehicle under test.

[0060] C2: Turn on the excitation light source, set the light of the vehicle under test to the test mode, and make the vehicle under test drive according to the set requirements. The GPS positioning system records the distance between the vehicle under test and the diffuser screen in real time;

[0061] C3: During the driving of the vehicle under test, use the GPS time synchronization module to trigger the imaging measurement unit to obtain two or more sets of spot images on the diffuser screen at a fixed frequency;

[0062] C4: Use the data processing and analysis unit to perform noise removal, image correction, position relationship calibration, contour recognition processing, etc. on the spot images, and analyze to obtain the spatial light distribution data of the light of the vehicle under test.

[0063] C5: Analyze the spatial light distribution data. Specifically, filter and denoise the acquired light intensity or illuminance data to obtain data D. f ; For data D f Perform enhancement and threshold segmentation to obtain the occlusion area 6 and the area where the excitation light source is located; calculate occlusion information such as the position, width W, height H, and area of the occlusion area 6 in combination with the relative positions of the occlusion area and the excitation light source, where the area of the occlusion width is W×H.

[0064] C6: Correspond the distance between the measured vehicle and the diffuser screen with the obtained occlusion information through GPS time to obtain the light occlusion information, occlusion range distribution, spatial light intensity or illuminance data, etc. of the measured vehicle at different distances.

[0065] In this embodiment, the headlight of the measured vehicle is generally an adaptive high beam. When the excitation light source is detected, in order to avoid causing glare interference to the opposite side, part of the light can be automatically reduced or switched, thus forming an occlusion area on the diffuser screen. The occlusion information includes the position, width, and height of the occlusion area, etc., and can be used to characterize the occlusion performance of the measured vehicle's light. Calculate the occlusion width and height according to whether the occlusion area falls on the excitation light source. Figure 2 、 Figure 3 、 Figure 4 They are respectively schematic diagrams of the occlusion areas when three measured vehicles drive to different positions. Good occlusion performance means not causing glare to the oncoming driver and not affecting the vision of the driver of the measured vehicle at the same time, that is, the width of the occlusion area should be no less than the distance between the left and right rearview mirrors, the height of the occlusion area should be higher than the glare point of the oncoming vehicle driver, and the position of the occlusion should not exceed the lane where the oncoming vehicle is located.

[0066] In this embodiment, the measured vehicle travels according to the set requirements to obtain distance data with corresponding GPS time; when the vehicle starts to travel, the GPS time synchronization module triggers the imaging measurement unit to start sampling synchronously at a fixed frequency, thereby obtaining occlusion information with GPS time; the data processing and analysis unit corresponds the occlusion information with the distance between the vehicle and the diffuser screen by comparing the GPS time to obtain the light occlusion information of the measured vehicle at different distances, or obtains the occlusion range distribution of the measured vehicle. The operation is simple, the measurement is fast, efficient, and accurate.

[0067] In this embodiment, taking the single-point illuminance value in the illuminance distribution on the diffuser screen as an example, after synchronizing and aligning the illuminance and the distance through GPS time, it can be obtained as Figure 5The distance-illuminance diagram shown is used to obtain the illuminance curve diagrams at different distances. In this embodiment, the spatial light intensity or illuminance data of the vehicle under test at different distances can be further utilized to analyze the illuminance information at the glare point of the oncoming vehicle or at the rearview mirror when following a vehicle at different distances, as well as the road surface illuminance information of other lanes after conversion, so as to further obtain the glare and visibility information of the vehicle under test's lights. Taking a sedan as an example, in the oncoming vehicle scenario, the glare point of the driver is usually at a position 1.1 m in height and 0.15 m to the left of the longitudinal axis of the excitation light source. According to the coordinate system and geometric relationship of the measuring device, this position is mapped to the corresponding area on the diffuser screen. The single-point illuminance information of the position corresponding to the glare point at different distances is extracted from the measured light intensity or illuminance distribution data on the diffuser screen at different distances. By observing and analyzing the changes in the illuminance values of the glare point at different distances, if the illuminance values exceed the threshold range in certain distance ranges, it indicates that at these distances, the lights of the vehicle under test may have a strong glare effect on the oncoming driver. In the scenario of following a vehicle in the same direction, the rearview mirror positions include the interior rearview mirror and the exterior rearview mirror. The position of the interior rearview mirror is usually at a height of 1.2 m and at the symmetric center of the excitation light source, and the position of the exterior rearview mirror is usually at a height of 0.9 m, deviating 0.9 m to the left and right of the longitudinal axis of the excitation light source respectively. Similarly, according to the coordinate system and geometric relationship of the measuring device, the corresponding areas of these positions on the diffuser screen are determined, and the illuminance values of the corresponding positions of the interior and exterior rearview mirrors at different distances are respectively extracted from the diffuser screen illuminance distribution data. The illuminance values at the interior and exterior rearview mirrors reflect the illumination effect of the vehicle under test's lights on the driver's view of the rearview mirror when following a vehicle. By analyzing the changes in the illuminance values at the rearview mirror at different distances, if the illuminance values are too high, it may cause the reflected light of the rearview mirror to be too strong, making it difficult for the driver to see the vehicle behind clearly and affecting driving safety. In addition, a mathematical model can be established based on the irradiation angle of the vehicle's lights, the scattering characteristics of the diffuser screen, and the geometric relationship to convert the illuminance data on the diffuser screen into the illuminance information of the road surface of other lanes. Using the established conversion model, the illuminance data on the diffuser screen at different distances is converted into the corresponding illuminance values of the road surface of other lanes, so that the light intensity distribution or illuminance distribution of the vehicle under test's lights on the road surface of other lanes at different distances can be obtained. Analyzing the converted road surface illuminance information helps to improve the driver's visibility of other lanes and ensure driving safety.

[0068] Embodiment 2

[0069] Different from Embodiment 1, as Figure 6As shown in the figure, in this embodiment, an infrared sensor is used to obtain the distance between the vehicle under test and the diffuser screen. Specifically, multiple groups of infrared sensors are fixedly arranged on the driving path of the vehicle. The positions of the infrared sensors and the diffuser screen are both known, and the infrared sensors and the imaging measurement unit are both communicatively connected to the same control unit. During the driving process of the vehicle under test along the set path, when the vehicle under test passes through the position where the infrared sensor is located, the control unit reads the signal triggered by the infrared sensor and simultaneously triggers the imaging measurement unit to perform measurement, so as to obtain the occlusion information on the diffuser screen at the specified distance.

[0070] In this embodiment, the imaging measurement unit can also be used to collect the spot images on the diffuser screen at a fixed frequency; when the vehicle under test passes through the position where the infrared sensor is located, the control unit records the time node when the infrared sensor is triggered, and corresponds the distance between the vehicle under test and the diffuser screen with the spot images obtained by the imaging measurement unit based on this time node, so as to obtain the occlusion information or the occlusion range distribution at different distances. In this embodiment, a fixed bracket can also be used instead of the excitation vehicle to place the excitation light source, and the excitation light source used is a rear position lamp or a light source simulating the spatial light intensity and color distribution of the rear position lamp.

[0071] Embodiment 3

[0072] Taking the scenario of following a vehicle in the same direction as an example, as Figure 7 shown, it includes a vehicle under test 4, an excitation light source 1, an imaging measurement unit 3, a diffuser screen 2, a data processing and analysis unit 7, and a control unit; the vehicle under test and the excitation vehicle are in adjacent lanes. A laser rangefinder is installed on the vehicle under test 4. The excitation light source 1 is a headlamp system installed on the excitation vehicle and faces the vehicle under test 4. The data processing and analysis unit 7 and the control unit are respectively communicatively connected to the imaging measurement unit 3. The diffuser screen 2 is arranged at a position 10 cm away from the excitation light source 1 between the excitation light source 1 and the vehicle under test 4, and the diffusing surface faces the vehicle under test 4. Two light-emitting holes 5 adapted to the position and size of the excitation light source 1 are opened on the diffuser screen 2.

[0073] This embodiment also provides a method for testing the light occlusion performance. Taking an oncoming vehicle as an example, the vehicle under test and the excitation vehicle are in adjacent lanes. The imaging measurement unit is placed at a certain angle facing the diffusing surface of the diffuser screen. The width of the diffuser screen covers three lanes, and the height is not less than the height of the excitation vehicle, generally 2 meters. The initial distance between the vehicle under test and the excitation vehicle is generally greater than 400 m, and the driving speed is not less than 60 km / h. The following specific steps are carried out to measure the light occlusion performance of the vehicle under test:

[0074] D1: Set the lights of the vehicle under test to the test mode, and make the vehicle under test drive according to the set requirements. The laser rangefinder records the distance between the vehicle under test and the diffuser screen and transmits the distance information to the data processing and analysis unit;

[0075] D2: The excitation light source is initially in the off state. When the laser rangefinder measures that the vehicle under test has traveled to the specified distance, the excitation light source is turned on. By combining the time when the excitation light source is turned on and the time when the spatial light intensity or illuminance data on the diffuser screen changes significantly, it is further determined whether the lights of the vehicle under test are excited and the response time information of the vehicle under test.

[0076] D3: When the laser rangefinder measures that the vehicle under test has traveled to the specified distance, the data processing and analysis unit transmits an instruction to the control unit, and the control unit triggers the imaging measurement unit to take pictures to obtain two or more spot images on the diffuser screen;

[0077] D4: Use the data processing and analysis unit to analyze the spot images to obtain the spatial light distribution data of the lights of the vehicle under test;

[0078] D5: Analyze the spatial light distribution data to obtain the shielding information of the vehicle under test corresponding to the dark area of the diffuser screen;

[0079] D6: Based on the ranging time of the laser rangefinder read by the control unit, the distance between the vehicle under test and the diffuser screen is corresponded to the spot images obtained by the imaging measurement unit, and then the corresponding relationship between the spot images and the distance between the vehicle under test and the diffuser screen is obtained, and then the shielding range distribution of the vehicle under test is obtained, and the shielding information of the vehicle under test at different distances is obtained.

[0080] In this embodiment, the spatial light intensity or illuminance data of the vehicle under test at different distances can also be used to analyze the glare point of the oncoming vehicle driver or the illuminance information at the rearview mirror when following the vehicle corresponding to different distances, and the road surface illuminance information of other lanes after conversion, and further obtain the glare and visibility information of the lights of the vehicle under test.

[0081] In this embodiment, since the light intensity of the headlight on the vehicle is generally strong, it is necessary to reasonably adjust the integration time of the imaging measurement unit to ensure that the measurement does not overflow.

[0082] The specific implementation manners of the present invention have been described above in conjunction with the accompanying drawings. However, those skilled in the art should understand that the above embodiments are only for illustration and not for limiting the scope of the present invention. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present invention. The protection scope of the present invention is defined by the appended claims.

Claims

1. A method for testing the light shielding performance, characterized in that The light shielding performance of a vehicle under test is measured using an excitation light source, a diffuser screen, and an imaging measurement unit. The diffuser screen is arranged between the excitation light source and the vehicle under test, and the diffusing surface faces the vehicle under test. An optical output hole is formed in the diffuser screen, and the light beam of the excitation light source is emitted from the optical output hole. The imaging measurement unit is aligned with the diffuser screen and obtains the light spot formed on the diffuser screen by the light of the vehicle under test. The specific measurement steps include: S1: Turn on the excitation light source, set the light of the vehicle under test to the test mode, and make the vehicle under test travel according to the set requirements; S2: During the travel of the vehicle under test, use the imaging measurement unit to obtain two or more light spot images on the diffuser screen; S3: Use the data processing and analysis unit to analyze the light spot images to obtain the spatial light distribution data of the light of the vehicle under test; S4: Analyze the spatial light distribution data to obtain the light shielding information of the vehicle under test corresponding to the dark area of the diffuser screen.

2. The method for testing the light shielding performance according to claim 1, characterized in that In step S2, while the imaging measurement unit obtains the light spot image, the corresponding relationship between the current light spot image and the distance between the vehicle under test and the diffuser screen is obtained by using a synchronous communication method.

3. The method for testing the light shielding performance according to claim 2, wherein A GPS positioning system is installed on the vehicle under test; the imaging measurement unit is triggered to take pictures through GPS signals, and the distance between the vehicle under test and the diffuser screen is corresponding to the light spot images obtained by the imaging measurement unit in the GPS time dimension.

4. A method for testing the light shielding performance according to claim 2, characterized in that, It further includes a control unit and infrared sensors respectively arranged at one or more specified positions away from the diffuser screen. The infrared sensors and the imaging measurement unit are respectively in communication connection with the control unit; when the vehicle under test travels to the specified distance, the control unit reads the signal triggered by the infrared sensor and simultaneously triggers the imaging measurement unit to perform measurement, so as to obtain the light spot image on the diffuser screen at the specified distance, or the imaging measurement unit continuously collects the light spot images on the diffuser screen; based on the time when the control unit reads the signal triggered by the infrared sensor, the distance between the vehicle under test and the diffuser screen is corresponding to the light spot images obtained by the imaging measurement unit.

5. A method for testing the light shielding performance according to claim 2, characterized in that It further includes a laser rangefinder and a control unit. The laser rangefinder and the imaging measurement unit are respectively in communication connection with the control unit; when the laser rangefinder measures that the vehicle under test travels to the specified distance, the control unit triggers the imaging measurement unit to perform measurement, so as to obtain the light spot image on the diffuser screen at the specified distance, or the imaging measurement unit continuously collects the light spot images on the diffuser screen; the control unit continuously reads the distance information transmitted by the laser rangefinder at different times, and based on the ranging time of the laser rangefinder read by the control unit, the distance between the vehicle under test and the diffuser screen is corresponding to the light spot images obtained by the imaging measurement unit.

6. The method for testing the light shielding performance according to claim 5, characterized in that The laser rangefinder is fixedly installed in front of the vehicle under test and moves together with the vehicle under test. The laser rangefinder is used to measure the distance between the vehicle under test and the diffuser screen; or the laser rangefinder is fixedly installed at one or more specified positions away from the diffuser screen, and the laser rangefinder is used to measure the distance between the vehicle under test and the laser rangefinder.

7. A method for testing the light shielding performance according to claim 1, characterized in that The lighting shielding performance test of the vehicle under test includes the test scenarios of oncoming vehicle meeting and following vehicle in the same direction; when the test scenario is oncoming vehicle meeting, the vehicle under test and the excitation light source are arranged in adjacent lanes, and the excitation light source is a headlamp or a lamp simulating a headlamp; when the test scenario is following vehicle in the same direction, the vehicle under test and the excitation light source are arranged in the same lane, and the excitation light source is a rear position lamp or a lamp simulating a rear position lamp.

8. A method for testing the light shielding performance according to claim 1, characterized in that, The field of view angle of the imaging measurement unit covers the diffuser screen, and its position does not block the light beam of the vehicle under test.

9. A method for testing the light shielding performance according to claim 1, characterized in that, Step S3 also includes performing noise removal, position relationship calibration, and contour recognition processing on the obtained spot image.

10. A method for testing the light shielding performance according to claim 9, characterized in that, The specific position relationship calibration includes: calibrating the corresponding relationship between the pixels of the imaging measurement unit and the spatial position of the diffuser screen through the spatial geometric position relationship; or using a light source with a known emission angle and clear contour at a specified position to calibrate the corresponding relationship between the pixels of the imaging measurement unit and the spatial position of the diffuser screen; or combining the above two methods to calibrate the corresponding relationship between the pixels of the imaging measurement unit and the spatial position of the diffuser screen.

11. A method for testing the light shielding performance according to claim 1, characterized in that, It also includes calibrating the response of the imaging measurement unit using a standard light source with a known light intensity distribution. The light emitted by the standard light source irradiates the diffuser screen, and the imaging measurement unit aligns to measure the spot formed by the standard light source on the diffuser screen. Each point in the diffuser screen spot corresponds to the pixel of the array detector in the imaging measurement unit. Since the spatial light intensity distribution of the standard light source is known, the response values of each pixel in the imaging measurement unit are calibrated; the calibrated imaging measurement unit is used to measure and analyze the spatial light intensity or illuminance data of the vehicle under test's lighting.

12. A method for testing the light shielding performance according to claim 2, characterized in that, It also includes using the obtained spatial light intensity or illuminance data of the vehicle under test at different distances to analyze the illuminance information at the driver's glare point when meeting oncoming vehicles or at the rearview mirror when following vehicles corresponding to different distances, and the illuminance information of the road surface in other lanes after conversion, and further obtaining the glare and visibility information of the vehicle under test's lighting.

13. A method for testing the light shielding performance according to claim 2, characterized in that, The excitation light source is initially in the off state. When the vehicle under test travels to a specified distance, the excitation light source is lit. By combining the time when the excitation light source is lit and the time when the spatial light intensity or illuminance data on the diffuser screen changes significantly, it is further determined whether the lighting of the vehicle under test is excited and the response time information of the vehicle under test.

14. A test device for the method of testing the light shielding performance according to claim 1, characterized in that, It includes an excitation light source, a diffuser screen, an imaging measurement unit, and a data processing and analysis unit; the diffuser screen is arranged between the excitation light source and the vehicle under test with the diffusing surface facing the vehicle under test. An exit hole is opened on the diffuser screen, and the size of the exit hole matches the size of the light exit surface of the excitation light source. The imaging measurement unit is arranged on one side of the vehicle under test and is aligned with the diffuser screen to obtain the spot image formed by the lighting of the vehicle under test on the diffuser screen. The data processing and analysis unit analyzes the spot image to obtain the lighting shielding information of the vehicle under test.

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