Apparatus and method for correcting headlamp leveling

Abstract

The present invention provides an apparatus and method for correcting headlight level. By specifying a headlight cutoff level using the horizontal and vertical lengths of a license plate frame image, the driver's line of sight is fully ensured while minimizing the impact on the line of sight of the driver of the preceding vehicle. The specified level is compared with a target level calculated based on changes in inter-vehicle distance. The method includes determining whether a headlight level correction is needed to raise or lower the headlight level, and correcting the headlight level so that the headlight cutoff follows the target level corresponding to the inter-vehicle distance.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2021-0042173, filed on March 31, 2021, which is hereby incorporated by reference in its entirety. Technical Field

[0003] The present invention relates to a device and method for correcting the level of a headlamp, which can automatically correct the lighting angle of the headlamp to a preset ideal target line or induce the driver to perform a correction operation. Background Art

[0004] Recently, headlamp leveling devices (HLLDs) applied to vehicles include switch types that require the driver to perform an operation to adjust the headlamp level, and automatic correction types that automatically adjust the headlamp level. Depending on the switch type, the driver adjusts the height of the headlamp by moving the switch provided in the vehicle upward and downward, but it is not uncommon to use it, and it is not difficult to find the appropriate height.

[0005] In addition, the manual HLLD system can adjust the height of the headlights according to the driver's decision. However, since once the headlight height is corrected, no further adjustments will be made even if the vehicle's posture changes, when the headlights are set at a high angle, it may cause inconvenience to the drivers of the vehicle in front or oncoming vehicles. Conversely, when the headlights are set at a low angle, it is impossible to ensure an appropriate visual distance.

[0006] According to the automatic correction type, the height of the headlights is automatically corrected by using sensors to obtain the height of the headlights. However, the use of a total of two to four sensors on the front and rear axles leads to increased costs. In addition, since it is difficult to accurately sense the vehicle's posture when using only the rear axle sensors, the headlight level may be excessively lowered. Therefore, even in a manual HLLD system, the convenience of operation can be improved by allowing the driver to intuitively recognize whether the headlight level needs to be adjusted and the degree of adjustment of the headlight level. In an automatic HLLD system, a device is provided that improves the accuracy of headlight level correction through precise sensing while eliminating the cost increase factor by minimizing the addition of sensors. Summary of the Invention

[0007] The present invention is intended to solve the above-mentioned problems in the prior art while fully maintaining the advantages achieved by the prior art.

[0008] One aspect of the present invention provides an apparatus and method for correcting headlamp levels, wherein a driver's line of sight can be fully ensured while minimizing the impact on the line of sight of a preceding vehicle driver by using the horizontal and vertical lengths of a license plate frame image to specify a headlamp cutoff level, comparing the specified level with a target level calculated based on a change in an inter-vehicle distance, determining whether a correction to raise or lower the headlamp level is required, and correcting the headlamp level so that the headlamp cutoff level follows the target level corresponding to the inter-vehicle distance.

[0009] The technical problems solved by the present invention are not limited to the aforementioned problems. Based on the following description, those skilled in the art to which the present invention belongs will clearly understand any other technical problems not mentioned herein.

[0010] According to one aspect of the present invention, an apparatus for correcting headlight level may include: a license plate frame image extractor configured to acquire a license plate frame image from an image of a preceding vehicle captured by a camera provided in a vehicle; a license plate frame analyzer configured to calculate an inter-vehicle distance to the preceding vehicle using a lateral length of the license plate frame image, and to divide a reference height of a rear region of the preceding vehicle, where the license plate frame is spaced from the ground, into a plurality of unit regions using a vertical length of the license plate frame image; the headlight level comparator configured to compare a cutoff level at which light from the headlight reaches the preceding vehicle with a target level, which is a preset ideal cutoff level, and determine the necessity of headlight level correction; and the headlight level corrector configured to raise the headlight level in response to determining that the cutoff level is below the target level, and to lower the headlight level when the cutoff level is above the target level, to perform correction so that the cutoff line of the headlight follows the target level corresponding to the inter-vehicle distance.

[0011] Furthermore, the license plate frame analyzer may include a distance calculator configured to calculate the inter-vehicle distance to the preceding vehicle using the horizontal length of the license plate frame image, and a reference height divider configured to evenly divide the reference height of the rear region of the preceding vehicle, where the license plate frame is spaced from the ground, into a plurality of unit region heights using the vertical length of the license plate frame image. The distance calculator may be configured to calculate the inter-vehicle distance to the preceding vehicle by comparing the horizontal length of the license plate frame image measured on the license plate frame image with the horizontal length of a standard license plate to derive a proportional relationship therebetween.

[0012] Furthermore, the license plate frame analyzer may be configured to correct the inter-vehicle distance result calculated by the distance calculator by utilizing the inter-vehicle distance to the preceding vehicle measured by a front radar sensor provided in the vehicle. The reference height divider may be configured to evenly divide the vertical length of the license plate frame appearing on the license plate frame image into a plurality of unit areas having the same height, and then evenly divide the reference height of the rear area of the preceding vehicle, from the lower end of the license plate frame to the ground, into the unit areas.

[0013] The headlight level corrector may be configured to automatically perform correction to raise or lower the headlight level so that the cutoff line of the headlights reaches a target line when an automatic correction type headlight level adjustment device that automatically adjusts the headlight level is provided. When the automatic correction type headlight level adjustment device is provided, a main correction of the headlight level is preemptively performed based on a result recognized by a provided sensor, and the headlight level correction device further raises or lowers the headlight level so that the cutoff line of the headlights reaches the target line, thereby performing correction.

[0014] Furthermore, the headlight level corrector may be configured to, when a switch-type headlight level adjustment device is configured, output a voice or pop-up message requesting that the headlight level be corrected to raise or lower the headlight level so that the headlight cutoff line reaches the target line. The device may further include a headlight level indicator configured to simultaneously display the target line and the cutoff line on the image of the preceding vehicle when displaying a front image including the preceding vehicle on a display unit provided in the vehicle. The headlight level indicator may be configured to simultaneously display the preceding vehicle image, the cutoff line, and the target line on the windshield when the vehicle is equipped with a head-up display (HUD).

[0015] According to one aspect of the present invention, a method for correcting a headlamp level may include: acquiring a license plate frame image from an image of a preceding vehicle captured by a camera provided in a vehicle; calculating an inter-vehicle distance to the preceding vehicle by utilizing a lateral length of the license plate frame image, and dividing a reference height of a rear region of the preceding vehicle, where the license plate frame is spaced from the ground, into a plurality of unit regions by utilizing a vertical length of the license plate frame image; comparing a cutoff level at which light from a headlamp reaches the preceding vehicle with a target line level as a preset ideal cutoff line, and determining necessity of headlamp level correction; and raising the headlamp level in response to determining that the cutoff level is lower than the target line, and lowering the headlamp level when the cutoff level is higher than the target line, to perform correction so that the cutoff line of the headlamp follows the target line level corresponding to the inter-vehicle distance.

[0016] Analyzing the license plate frame may include calculating the inter-vehicle distance to the preceding vehicle using a horizontal length of the license plate frame image; and evenly dividing a reference height of a rear region of the preceding vehicle, where the license plate frame is spaced from the ground, into a plurality of unit regions using a vertical length of the license plate frame image. Calculating the distance may include calculating the inter-vehicle distance to the preceding vehicle by comparing the horizontal length of the license plate frame image measured on the license plate frame image with the horizontal length of a standard license plate to derive a proportional relationship therebetween.

[0017] Furthermore, the inter-vehicle distance calculated when calculating the distance is corrected by using the inter-vehicle distance to the preceding vehicle measured by a front radar sensor provided in the vehicle. Dividing the reference height may include evenly dividing the vertical length of the license plate frame appearing on the license plate frame image into a plurality of unit areas having the same height, and then evenly dividing the reference height of the rear area of the preceding vehicle from the lower end of the license plate frame to the ground into the heights of the unit areas.

[0018] Furthermore, correcting the headlight level may include automatically performing a correction to raise or lower the headlight level so that the cutoff line of the headlights reaches a target line when an automatic correction type headlight level adjustment device is provided. When the automatic correction type headlight level adjustment device is provided, a main correction of the headlight level may be performed in advance based on a result recognized by a provided sensor, and when correcting the headlight level, the headlight level may be further raised or lowered so that the cutoff line of the headlights reaches the target line, thereby performing the correction.

[0019] Correcting the headlight level may include, when a switch-type headlight level adjustment device is provided, outputting a voice or pop-up message requesting that the headlight level be corrected to raise or lower the level so that the cutoff line of the headlights reaches a target line. Furthermore, the method may include, when displaying a front image including a preceding vehicle on a display unit provided in the vehicle, simultaneously indicating the target line and the cutoff line on the preceding vehicle image. Displaying the headlight level may include, when the vehicle is provided with a head-up display (HUD), simultaneously outputting the preceding vehicle image, the cutoff line, and the target line on the windshield. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description presented in conjunction with the accompanying drawings, in which:

[0021] Figure 1 is a block diagram of an apparatus for correcting headlamp leveling according to the present invention;

[0022] Figure 2 is an exemplary schematic diagram showing the standard of a license plate;

[0023] Figure 3is an exemplary schematic diagram showing an image of a preceding vehicle captured at various inter-vehicle distances according to the present invention;

[0024] Figure 4 is an exemplary schematic diagram illustrating size differences of license plates of preceding vehicles photographed at various inter-vehicle distances according to the present invention;

[0025] Figure 5 is an exemplary schematic diagram showing that a license plate image to be recognized is divided into equal intervals according to the present invention;

[0026] Figure 6 is an exemplary schematic diagram showing how to calculate the height of a license plate frame from the ground by using the segmentation result of a license plate image according to the present invention;

[0027] Figure 7 is an exemplary schematic diagram illustrating calculation of the height of the license plate frame from the ground for various distances between vehicles according to the present invention;

[0028] Figure 8 is an exemplary schematic diagram showing a target line representing an ideal lighting angle of a headlamp according to the present invention;

[0029] Figure 9 is an exemplary schematic diagram showing a headlamp being excessively lowered;

[0030] Figure 10 is an exemplary schematic diagram showing a headlamp being excessively raised;

[0031] Figure 11 is an exemplary schematic diagram showing that a state in which a target line is lowered as the inter-vehicle distance to a preceding vehicle becomes larger is applied to a vehicle according to the present invention;

[0032] Figure 12 is an exemplary schematic diagram showing a state in which a cutoff line of a headlamp according to the present invention is lower than a target line;

[0033] Figure 13 is an exemplary schematic diagram showing a state in which a cutoff line of a headlamp according to the present invention is higher than a target line;

[0034] Figure 14 is an exemplary diagram illustrating a comparison result of indicating a target line of a headlamp and a cutoff line of a headlamp on an output screen of a multifunctional camera (MFC) according to the present invention;

[0035] Figure 15 is an exemplary diagram illustrating a comparison result of indicating a target line of a headlamp and a cutoff line of the headlamp on a windshield through a head-up display (HUD) according to the present invention;

[0036] Figure 16is a block diagram of a method for correcting headlight leveling according to the present invention; and

[0037] Figure 17 is a flowchart illustrating a process of determining whether it is necessary to correct the headlight level, automatically correct the headlight level, or request the driver to make correction according to the present invention. DETAILED DESCRIPTION

[0038] Hereinafter, some embodiments of the present invention will be described in detail with reference to the exemplary drawings. When adding reference numerals to the components of each figure, it should be noted that even if the same or equivalent components are shown in other figures, the same reference numerals are used to designate the same or equivalent components. In addition, when describing the embodiments of the present invention, if it is determined that the detailed description of related known configurations or functions interferes with the understanding of the embodiments of the present invention, they will be omitted.

[0039] It should be understood that the term "vehicle" or "vehicular" or other similar terms used herein generally include motor vehicles, such as passenger vehicles including sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, ships including various boats, vessels, aircraft, etc., and include hybrid vehicles, electric vehicles, internal combustion engine vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g., fuels derived from non-petroleum energy sources).

[0040] Although the exemplary embodiments are described as utilizing multiple units to perform the exemplary processes, it should be understood that the exemplary processes can also be performed by one or more modules. Furthermore, it should be understood that the term controller / control unit refers to a hardware device that includes a memory and a processor and is specifically programmed to perform the processes described herein. The memory is configured to store the modules, and the processor is specifically configured to execute the modules to perform one or more processes described further below.

[0041] Furthermore, the control logic of the present invention can be implemented as non-volatile computer-readable media on a computer-readable medium containing executable program instructions executed by a processor, controller / control unit, or the like. Examples of computer-readable media include, but are not limited to, ROM, RAM, compact disc (CD)-ROMs, magnetic tapes, floppy disks, flash drives, smart cards, and optical data storage devices. The computer-readable recording medium can also be distributed among network-connected computer systems so that the computer-readable media is stored and executed in a distributed manner, such as by a telematics server or a controller area network (CAN).

[0042] When describing components according to embodiments of the present invention, terms such as first, second, A, B, (a), (b) etc. can be used. These terms are only used to distinguish one component from another component, and these terms do not limit the nature, order or sequence of the components. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as those generally understood by those of ordinary skill in the art to which the present invention belongs. It should be further understood that those terms defined in commonly used dictionaries should be interpreted as having the same meaning as the meaning in the context of the relevant technology, and should not be interpreted as ideal or too formal meanings, unless expressly provided herein.

[0043] In the following, reference will be made to Figures 1 to 17 Embodiments of the present invention are described in detail. Figure 1 is a block diagram of an apparatus for correcting headlamp leveling according to the present invention.

[0044] refer to Figure 1 The apparatus for correcting the headlight level according to the present invention may include: a license plate frame image extractor 100, a license plate frame analyzer 200, a headlight level comparator 300, and a headlight level corrector 400, wherein the license plate frame image extractor 100 is configured to obtain a license plate frame image from an image of a preceding vehicle captured by a camera provided in a vehicle; the license plate frame analyzer 200 is configured to calculate the inter-vehicle distance to the preceding vehicle by using the lateral length of the license plate frame image, and to calculate the inter-vehicle distance to the preceding vehicle by using the vertical length of the license plate frame image to separate the license plate frame from the ground. The reference height of the rear area of the vehicle is divided into a plurality of unit areas; the headlamp level comparator 300 is configured to compare the cutoff level of the headlamp light reaching the leading vehicle with the target line level as a preset ideal cutoff line, and determine the necessity of headlamp level correction; the headlamp level corrector 400 is configured to increase the headlamp level in response to determining that the cutoff level is lower than the target line, and to reduce the headlamp level when the cutoff level is higher than the target line, so as to perform correction so that the cutoff line of the headlamp follows the target line level of the corresponding vehicle-to-vehicle distance.

[0045] The license plate frame image extractor 100 may be configured to extract a license plate frame image from a preceding vehicle image captured by a camera provided in the vehicle, and measure a size of the extracted license plate frame image.

[0046] Generally speaking, the standards for license plates are determined by country, such as Figure 2 As shown in the figure, the standard for Korean license plates is 520mm in horizontal length and 110mm in vertical length. The size of the license plate frame image extracted in this way becomes smaller as the distance between vehicles (the distance between the preceding vehicle and the vehicle equipped with the camera) increases. In other words, as Figure 3As shown, as the inter-vehicle distance increases to 5m, 10m, and 15m, the size of the preceding vehicle image captured by the camera decreases.

[0047] Therefore, the horizontal length of the license plate frame image extracted from the front vehicle image also decreases as the distance between vehicles increases, e.g. Figure 4 As shown, the inter-vehicle distance measured when the inter-vehicle distance is 5 meters is L1, the inter-vehicle distance measured when the inter-vehicle distance is 10 meters is L2, and the inter-vehicle distance measured when the inter-vehicle distance is 15 meters is L3. In other words, the horizontal length of the license plate frame image decreases in proportion to the increase in the inter-vehicle distance.

[0048] The license plate frame analyzer 200 may include: a distance calculator 210 and a reference height divider 220, wherein the distance calculator 210 is configured to calculate the inter-vehicle distance to the preceding vehicle by using the horizontal length of the license plate frame image; and the reference height divider 220 is configured to evenly divide the reference height of the license plate frame of the rear area of the preceding vehicle (the reference height between the license plate frame and the ground) into a plurality of unit areas by using the vertical length of the license plate frame image.

[0049] Then, the distance calculator 210 may be configured to calculate the inter-vehicle distance to the preceding vehicle by comparing the horizontal length of the license plate frame image measured on the license plate frame image with the horizontal length of the license plate standard to derive a proportional relationship thereof. In other words, Figure 3 and Figure 4 As shown, since the size of the preceding vehicle and the size of the license plate frame (particularly the lateral length) decrease proportionally with the increase of the inter-vehicle distance, the inter-vehicle distance to the preceding vehicle can be calculated by utilizing the degree of reduction in the lateral length of the license plate frame of a specific standard.

[0050] In this manner, distance calculator 210 can be configured to calculate the inter-vehicle distance to the preceding vehicle using the proportional relationship of the reduced lateral length of the license plate frame image, thereby deriving a target line level as the ideal cutoff line for the headlights at the calculated inter-vehicle distance. Furthermore, the inter-vehicle distance to the preceding vehicle can be measured using a front radar sensor mounted on the front side of the vehicle to detect the presence of an obstacle or preceding vehicle and measure the distance to the obstacle or preceding vehicle. This configuration allows for correction of the inter-vehicle distance calculated by distance calculator 210 and reduction of distance calculation errors.

[0051] The reference height divider 220 may be configured to divide the vertical length of the license plate frame appearing on the license plate frame image into the height and the vertical length. Figure 5 The rear area of the front vehicle is divided into the following units from the lower end of the license plate frame to the ground: Figure 6The height of the unit area shown in FIG, and the reference height divider 220 can be configured to calculate the sum of the heights of the unit areas as the reference height (height standard, HS) of the license plate frame. Figure 6 As shown in the figure, the base height refers to the height from the ground to the bottom of the license plate frame.

[0052] Therefore, as an example of dividing the vertical length of the license plate into multiple unit areas, Figure 5 As shown, a license plate frame having a vertical length of 110 mm can be divided into eleven unit areas having the same height of 10 mm. However, the vertical length of the license plate frame may be different according to the standards of license plates in various countries. It is obvious that the height of the unit area dividing the vertical length of the license plate frame and the number of the unit areas can be set differently without being limited to Figure 5 Example shown.

[0053] Therefore, the reference height divider 220 may be configured to calculate the proportional relationship of the vertical length of the license plate frame as a unit area of a fixed reference, without calculating the vertical length of the license plate frame by using the proportional relationship that the vertical length of the license plate frame relatively increases according to the change in the inter-vehicle distance from the preceding vehicle. Figure 7 As shown, the reference height (HS) can be calculated in the same manner for inter-vehicle distances of 15m, 10m, and 5m, regardless of the size increments of the preceding vehicle image captured by the camera and the size increments of the license plate frame image. In other words, when the inter-vehicle distance is 10m, as long as the reference height (HS), representing the height from the ground to the lower end of the license plate frame, is calculated as N unit areas (where N is an arbitrary integer), the reference height can be calculated in the same manner for inter-vehicle distances of 15m and 5m. This stable calculation of the reference height, regardless of inter-vehicle distance, allows for identification of changes in the headlamp cutoff level caused by relative changes in the cutoff level, such as when the front surface of the vehicle rises or falls due to the weight and arrangement of passengers or loaded cargo.

[0054] Furthermore, the headlight level comparator 300 can be configured to determine whether the headlight cutoff line has fallen below or risen above the target line due to the weight of passengers or cargo on board, or changes in the vehicle's posture (e.g., changes in position) by comparing the cutoff line level of the headlight light reaching the preceding vehicle with a target line level. To achieve this, the headlight level comparator 300 can be configured to determine to which unit area of the preceding vehicle's rear area (which is divided into a plurality of unit areas for calculating a reference height (HS)) the headlight cutoff line level corresponds. The position of the headlight cutoff line can be determined by a front camera (including a multi-function camera (MFC) pre-installed in the vehicle), and the position of the headlight cutoff line can be compared with a target line level pre-calculated based on the inter-vehicle distance.

[0055] Furthermore, the headlight level comparator 300 can be configured to calculate the position of the rear region of the preceding vehicle to which the target line, which is the ideal cutoff line of the headlight, corresponds. Thus, by identifying the reference height of the rear region of the preceding vehicle using a set of unit regions (obtained by evenly dividing the license plate frame of the preceding vehicle into specific sizes) and determining to which of the plurality of unit regions forming the rear region of the preceding vehicle the cutoff line and the target line correspond, the levels can be compared without having to compare the positions of the cutoff line and the target line of the headlight with numerical feature values.

[0056] Generally speaking, if Figure 8 As shown, the ideal state is defined as follows: light radiated from a vehicle headlamp at a height H1 is directed at a height h2, obtained by subtracting 100 mm from the headlamp's height h1, at a distance of 10 m from the front. Therefore, OEMs manufacturing vehicle headlamps initially set the headlamps so that the headlamp's cutoff line remains horizontal in this state.

[0057] Therefore, a line facing the height h2 (ie, height h1-100 mm) at a point 10 m from the front side can be set as an ideal cutoff line as the target line. The target line can be obtained by Figure 9 and Figure 10 The straight line shown faces the lower side of the headlamp while forming an angle of 0.57° (calculated by Formula 1 representing the initial setting condition). In Formula 1, based on the general initial setting condition for setting the target line, when the distance between vehicles is 10 meters, h1-h2 is 100 mm.

[0058] Formula 1

[0059]

[0060] The lighting angle of the headlights, which are initially set to form a target line, may be changed so that the cutoff line of the headlights becomes lower than the target line due to various reasons, such as when the front side of the vehicle is heavier than its rear side. Specifically, Figure 9 As shown, as the inter-vehicle distance to the preceding vehicle increases, the cutoff line of the headlight may become lower than the target line, which may hinder securing the driver's vision during nighttime driving.

[0061] In addition, when the rear side of the vehicle becomes heavier, for example, when passengers are on board or heavy cargo is loaded on the rear side of the vehicle, the front side of the vehicle can be raised so that the cutoff line of the headlight becomes higher than the target line. Specifically, as Figure 10 As shown, as the inter-vehicle distance to the preceding vehicle increases, the cutoff line of the headlight becomes higher than the target line, thereby possibly obstructing the vision of the driver of the preceding vehicle or a vehicle traveling in the opposite lane.

[0062] The target line height (h) calculated when the distance between the vehicle and the preceding vehicle is 5m, 10m, 15m, 20m and 25m x ) are respectively expressed as h when x (here, x is the distance between vehicles) is 5m x For "h a ", when x is 15m, h x For "h b ", when x is 20m, h x For "h c ", when x is 25m, h x For "h d ”, Figure 9 and Figure 10 It shows that as the distance between vehicles increases, the height of the target line increases from h a to h d Then, the point corresponding to the inter-vehicle distance of 0 m, that is, the installation height of the headlamp is represented by h1, and the height of the target line at the point corresponding to the inter-vehicle distance of 10 m (which represents the initial setting condition for generating the target line) is represented by h2.

[0063] Therefore, if Figure 11 As shown in FIG. 1 , when the target line level decreases in proportion to the degree of increase in the inter-vehicle distance, it can be more clearly recognized that the position of the unit area that matches the target line level is different in the unit area that divides the reference height from the license plate frame to the ground. In other words, Figure 11 It is shown that on the divided image corresponding to the height of the preceding vehicle with a distance between vehicles of 5 m, the target line is formed at a position h below the license plate closer to the reference height. aIt can be recognized that the target line is formed at a position h2 lower than ha on the divided image corresponding to the height of the preceding vehicle with a vehicle-to-vehicle distance of 10 m, and at a position h2 lower than h2 on the divided image corresponding to the height of the preceding vehicle with a vehicle-to-vehicle distance of 15 m. b Place.

[0064] Then, despite Figure 11 The target line is shown to be indicated on the preceding vehicle image when the interval of the inter-vehicle distance is 5 m, but it is obvious that the interval of the inter-vehicle distance can be set differently. Figure 12 As shown, the headlamp level comparator 300 can be configured to identify the position of the target line as the position of the unit area of the reference height divided at equal intervals on the front vehicle image, and the position of the target line is determined with reference to the vehicle-to-vehicle distance, which is calculated by measuring the lateral length of the license plate on the license plate image using a distance calculator.

[0065] In addition, if Figure 12 As shown, the headlamp level comparator 300 may be configured to identify the cutoff level of the headlamp using the position of the unit area dividing the reference height at equal intervals. Figure 12 and Figure 13 As shown in FIG, the cutoff line and target line of the headlamp are simultaneously located on the preceding vehicle image captured at the vehicle-to-vehicle distances of 5 m, 10 m, and 15 m, respectively, to make it easier to compare the positions of the cutoff line and the target line. Figure 12 and Figure 13 In the figure, for ease of comparison, the position of the target line is indicated by lines representing the height from the ground, such as ha, h2, and hb, and the current cutoff line of the headlamp is indicated by a shaded area from the ground to a specific height.

[0066] Then, Figure 12 It shows that when the distance between vehicles is 5m, 10m and 15m respectively, the cut-off line is located below the target line. Figure 13 The cutoff line of the headlight is shown to be higher than the target line when the inter-vehicle distance is 5m, 10m, and 15m, respectively. Based on the comparison result of the headlight level comparator 300, when the cutoff line is lower than or higher than the target line, it can be determined that the lighting angle of the headlight deviates from the ideal state, and therefore it can be determined that the headlight level needs to be corrected to follow the target line.

[0067] The headlight level corrector 400 can be configured to: when the cutoff line level is below the target line, perform correction to raise the headlight level so that the cutoff line reaches the target line height; when the cutoff line level is above the target line, perform correction to lower the headlight level so that the cutoff line reaches the target line height. Then, when an automatic correction type headlight level adjustment device (HLLD) that can automatically adjust the headlight level is provided, the headlight level corrector 400 can be configured to automatically perform correction to raise or lower the headlight level so that the cutoff line of the headlight reaches the target line. This can minimize the inconvenience caused by the headlight light to the driver of the preceding vehicle or vehicles traveling in the opposite lane while stably ensuring the driver's sight.

[0068] Therefore, when an automatic correction type headlamp level adjustment device (HLLD) is provided, a main correction of the headlamp illumination angle is immediately performed based on the result of recognition by the sensor or the like provided therein, and then the illumination angle of the headlamp can be further raised or lowered to reach the target line by the headlamp level corrector 400. In addition, when a switch type headlamp level adjustment device (HLLD) is provided (in which the adjustment of the headlamp level depends on the driver's manipulation), the headlamp level corrector 400 can be configured to output an indication in the form of voice or a message (including a pop-up window recognizable by the driver), for example, a warning that a correction of raising or lowering the headlamp level needs to be performed so that the cutoff line of the headlamp reaches the target line.

[0069] To this end, the embodiment of the present invention may further include a headlamp level indicator 500 that allows the driver to intuitively recognize whether the lighting angle of the headlamp needs to be corrected, and simultaneously provides information on the correction direction and correction degree by outputting a front image including the preceding vehicle on a display unit provided in the vehicle and simultaneously indicating a target line and a cutoff line on the preceding vehicle image in a superimposed manner. Figure 14 As shown, the headlamp level indicator 500 may be configured to simultaneously output or indicate a preceding vehicle image, a cutoff line, and a target line on a display unit displaying a multi-function camera (MFC) image.

[0070] When data that can be visually recognized by the driver can be indicated on the windshield by a head-up display (HUD) provided in the vehicle, such as Figure 15 As shown, the headlamp level indicator 500 can be configured to simultaneously output a front vehicle image (which is captured by a multi-function camera (MFC) provided in the vehicle), a cutoff line, and a target line on the windshield. Figure 15 In the HUD screen shown, the distance that the cutoff line must be raised or lowered to follow the target line height can be simultaneously calculated and indicated.

[0071] Next, we will refer to Figure 16 and Figure 17 A method for correcting the level of headlights according to another embodiment of the present invention is described. Figure 16 According to another embodiment of the present invention, a method for correcting headlight level may include: a license plate frame image extraction step S100, a license plate frame analysis step S200, a headlight level comparison step S300, and a headlight level correction step S400. The license plate frame image extraction step S100 acquires a license plate frame image from an image of a preceding vehicle captured by a camera provided in a vehicle; the license plate frame analysis step S200 calculates the inter-vehicle distance to the preceding vehicle by using the horizontal length of the license plate frame image, and compares the rear area of the preceding vehicle by using the vertical length of the license plate frame image. The headlight level comparison step S300 compares the cutoff level of the headlight light reaching the preceding vehicle with the target level as a preset ideal cutoff level, and determines the necessity of headlight level correction; the headlight level correction step S400 raises the headlight level in response to determining that the cutoff level is lower than the target level, and lowers the headlight level when the cutoff level is higher than the target level, so as to perform correction so that the cutoff line of the headlight follows the target level of the corresponding inter-vehicle distance.

[0072] In the license plate frame image extraction step ( S100 ), a license plate frame image can be extracted from an image of a preceding vehicle captured by a camera provided in the vehicle, and the size of the extracted license plate frame image can be measured. The size of the license plate frame image decreases proportionally with increasing inter-vehicle distance (the inter-vehicle distance separating the preceding vehicle from the vehicle including the camera). In other words, since the size of the preceding vehicle image decreases with increasing inter-vehicle distance, the lateral length of the license plate frame image extracted from a portion of the preceding vehicle also decreases proportionally with increasing inter-vehicle distance.

[0073] License plate frame analysis step S200 may include a distance calculation step S210, which calculates the inter-vehicle distance to the preceding vehicle using the horizontal length of the license plate frame image, and a reference height division step 220, which evenly divides the reference height of the rear area of the preceding vehicle (the reference height separating the license plate frame from the ground) into multiple unit areas using the vertical length of the license plate frame image. In distance calculation step S210, the inter-vehicle distance to the preceding vehicle may be calculated by comparing the horizontal length of the license plate frame measured on the license plate frame image with the horizontal length of a standard license plate to derive a proportional relationship.

[0074] Because the size of the preceding vehicle and the size of the license plate frame (specifically, the lateral length) decrease proportionally as the inter-vehicle distance increases, the inter-vehicle distance to the preceding vehicle can be calculated using the degree of reduction in the lateral length of the license plate frame of a specific standard. Therefore, in the distance calculation step ( S210 ), the inter-vehicle distance to the preceding vehicle can be calculated using the proportional relationship of the reduction in the lateral length of the license plate frame image, thereby deriving a target line level serving as the ideal cutoff line for the headlights based on the calculated inter-vehicle distance.

[0075] Furthermore, by using the inter-vehicle distance measured by the front radar sensor installed in the vehicle to correct the inter-vehicle distance calculated in distance calculation step S210, the calculation error of the inter-vehicle distance to the preceding vehicle can be reduced. In reference height division step 220, the vertical length of the license plate frame appearing on the license plate frame image can be evenly divided into a plurality of unit areas of equal height. The rear area of the preceding vehicle, from the bottom end of the license plate frame to the ground, can then be divided into the heights of the unit areas. The sum of the heights of the unit areas can be calculated as the reference height (HS) of the license plate frame. Specifically, the reference height (HS) refers to the height from the ground to the bottom end of the license plate frame.

[0076] The vertical length of the license plate frame may vary depending on the standards of each country's license plates. It is apparent that the height and number of unit areas that define the vertical length of the license plate frame may be set differently, without limitation to a specific embodiment. Furthermore, in the headlight level comparison step ( S300 ), by comparing the cutoff level (the level at which the headlight light reaches the preceding vehicle) with the target level, it is possible to determine whether the headlight cutoff level has fallen below or above the target level due to, for example, a change in vehicle posture.

[0077] To achieve this, in the headlamp level comparison step S300, it is possible to determine to which unit area of the rear area of the preceding vehicle (which is divided into a plurality of unit areas for calculating the reference height (HS)) the cutoff level (at which the light from the headlamp reaches the preceding vehicle) corresponds. Furthermore, in the headlamp level comparison step S300, it is possible to calculate to which position of the rear area of the preceding vehicle the target level, which is the ideal cutoff level of the headlamp, corresponds.

[0078] Therefore, in the headlight level comparison step S300, by identifying the reference height of the rear area of the leading vehicle using a set of unit areas (which are obtained by evenly dividing the license plate frame of the leading vehicle into specific sizes), and determining to which unit area of the multiple unit areas forming the rear area of the leading vehicle the cutoff line and the target line correspond, the levels can be compared without comparing the positions of the cutoff line and the target line of the headlight with the numerical feature values.

[0079] In the headlight level comparison step S300, based on the comparison result of the headlight level comparator 300, if the cutoff line is below or above the target line, it can be determined that the lighting angle of the headlights deviates from the ideal state, and thus it can be determined that a correction to raise or lower the headlight level is required to follow the target line level. In addition, in the headlight level correction step S400, the following control can be executed: when the cutoff line level is below the target line, the headlight level correction is performed to raise the headlight level so that the cutoff line reaches the target line level, and when the cutoff line level is above the target line, the headlight level correction is performed to lower the headlight level so that the cutoff line reaches the target line level.

[0080] Then, in the headlight leveling correction step S500, when an automatic correction type headlight leveling device (HLLD) that can automatically adjust the headlight level is provided, the correction of raising or lowering the headlight level can be automatically performed so that the cutoff line of the headlight reaches the target line. As a result, while stably ensuring the driver's line of sight, the inconvenience caused by the headlight light to the driving of the preceding vehicle or vehicles traveling in the opposite lane can be minimized. Therefore, when the automatic correction type headlight leveling device (HLLD) is provided, the main correction of the headlight illumination angle is immediately performed based on the results of recognition by the sensors provided therein, and then, in the headlight leveling correction step S500, the illumination angle of the headlight can be further raised or lowered to reach the target line.

[0081] In addition, in the headlamp level correction step S500, when a switch-type headlamp level adjustment device (HLLD) is set (in which the adjustment of the headlamp level depends on the driver's operation), an indication can be output in the form of a voice message (including a pop-up window that can be recognized by the driver), for example, a warning that a correction of raising or lowering the headlamp level needs to be performed so that the cutoff line of the headlamp reaches the target line.

[0082] Furthermore, the present invention may include a headlight level indication step (S400) that allows the driver to intuitively recognize whether the lighting angle of the headlights needs to be corrected. This step simultaneously provides information on the correction direction and degree of correction by indicating a front image including a preceding vehicle on a display unit provided in the vehicle and simultaneously indicating a target line and a cutoff line on the preceding vehicle image in a superimposed manner, thereby allowing the driver to recognize the determination result in the headlight level comparison step (S300). Therefore, in the headlight level indication step (S400), the preceding vehicle image, the cutoff line, and the target line may be simultaneously indicated on the display unit displaying the multi-function camera (MFC) image.

[0083] Furthermore, in the headlight level indication step (S400), when data visually recognizable to the driver can be output on the windshield via a head-up display (HUD) provided in the vehicle, the image of the preceding vehicle (captured by a multi-function camera (MFC) installed in the vehicle), the cutoff line, and the target line can be simultaneously indicated on the windshield. The distance by which the cutoff line must be raised or lowered to match the target line height can then be simultaneously calculated and indicated or output on the HUD screen. Therefore, since a comparison result of the current headlight cutoff line and target line levels can be provided, allowing the driver to visually recognize the result via the multi-function camera (MFC) or head-up display (HUD) screen, the convenience of headlight operation during nighttime driving can be improved. Furthermore, since the comparison of the cutoff line and target line of the headlights and the subsequent control can be performed based on the preceding vehicle image captured by a pre-installed camera in the vehicle, additional implementation costs can be minimized, and the present invention can be more easily applied to vehicles.

[0084] Next, we will refer to Figure 17 The process of correcting the headlight level by comparing the cutoff line of the headlight with the target line according to the present invention is described. Figure 17 As shown, it is possible to determine whether there is a preceding vehicle on the front side of the vehicle. When there is no preceding vehicle (No), the lighting angle of the headlights can be maintained at the previous value. When there is a preceding vehicle, the license plate frame image can be extracted from the preceding vehicle image taken by a camera provided in the vehicle, and then the horizontal and vertical lengths of the license plate frame image can be measured and analyzed.

[0085] Furthermore, the inter-vehicle distance to the preceding vehicle can be calculated by using the ratio of the reduction in the lateral length of the license plate frame to the standard lateral length of an actual license plate frame. This inter-vehicle distance calculated using the proportional relationship of the license plate frame image can then be compared with the inter-vehicle distance to the preceding vehicle identified using measurements from the vehicle's front radar sensor.

[0086] Thereafter, since the inter-vehicle distance is calculated again when the difference in the inter-vehicle distance exceeds the preset error range (No), and the inter-vehicle distance is specified when the difference is within the preset error range (Yes), the vertical length of the license plate frame image can be evenly divided into multiple unit areas with specific heights to calculate the target line level according to the specified inter-vehicle distance.

[0087] Furthermore, the rear area of the preceding vehicle can be divided into unit area heights, and the height of the area from the lower end of the license plate frame to the ground can be calculated using the sum of the unit area heights. After calculating the target line level based on the specified inter-vehicle distance, it is possible to determine where the target line level corresponds to among the multiple unit areas forming the rear area of the preceding vehicle.

[0088] In addition, it is possible to calculate at which position in the plurality of unit areas forming the rear area of the preceding vehicle the cutoff level (the point at which the light emitted from the vehicle's headlights reaches the rear area of the preceding vehicle at the cutoff level) reaches. When the vehicle includes a head-up display (HUD) (yes), by indicating the comparison result of the headlight's cutoff line and the target line, the driver's intuitive recognition convenience can be achieved. When the vehicle does not include a head-up display (HUD) (no), the driver's recognition can be achieved by indicating the comparison result of the headlight's cutoff line and the target line on the screen of the multi-function camera (MFC). When the vehicle includes an automatic correction device that can automatically correct the lighting angle of the headlights (yes), the lighting angle of the headlights can be automatically raised or lowered until the cutoff line of the headlights reaches the target line level.

[0089] Specifically, it is apparent that the driver can be notified of the correction via a pop-up image or voice message. If the vehicle does not include an automatic correction device for automatically correcting the headlight lighting angle (No), the driver can be notified via a pop-up message or voice message requesting the driver to adjust the headlight lighting angle to increase or decrease the headlight lighting angle. The driver can then manually correct the headlight lighting angle by manipulating a switch, etc., so that the headlight cutoff line reaches the target line level.

[0090] Thereafter, when the vehicle posture changes due to changes in the weight of the cargo or passengers on the vehicle or due to changes in the position of the cargo or passengers, the lighting angle of the headlights will change when the front side of the vehicle is lowered or raised. When it is determined again whether there is a vehicle in front, it can be determined whether the lighting angle of the headlights needs to be corrected.

[0091] According to the present invention, by comparing the cutoff line and the target line of the headlamp based on the image of the preceding vehicle captured by a camera provided in the vehicle, the cutoff line level of the headlamp can be corrected more accurately and conveniently, and the headlamp level can be adjusted so that the headlamp level follows the target line level, thereby minimizing the addition of sensors and minimizing the increase in cost.

[0092] Furthermore, according to the present invention, since a comparison result between the current cutoff line and the target line level of the headlight can be provided so that the driver can visually recognize the result through the screen of the multi-function camera (MFC) or the head-up display (HUD), the driver can intuitively determine the correction of the headlight level, thereby improving the convenience of headlight operation during nighttime driving. Furthermore, the present invention can provide various effects of direct or indirect recognition.

[0093] The above description is a simple example of the technical spirit of the present invention, and those skilled in the art to which the present invention belongs can make various corrections and modifications to the present invention without departing from the basic characteristics of the present invention.

[0094] Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but are provided to describe the present invention, and the scope of the technical spirit of the present invention is not limited by the embodiments. Therefore, the true technical scope of the present invention should be interpreted by the appended claims, and all technical spirits within the equivalent scope belong to the scope of the present invention.

Claims

1. A device for correcting the level of a headlamp, the device comprising: a license plate frame image extraction device configured to obtain a license plate frame image from a preceding vehicle image captured by a camera provided in the target vehicle; a license plate frame analysis device configured to calculate an inter-vehicle distance to a preceding vehicle using a lateral length of the license plate frame image, and to divide a reference height of a rear region of the preceding vehicle in which the license plate frame is spaced from the ground into a plurality of unit regions using a vertical length of the license plate frame image; a headlamp level comparison device configured to compare a cutoff line level at which light from the headlamp reaches a preceding vehicle with a target line level that is a preset ideal cutoff line, and determine the necessity of headlamp level correction; as well as A headlamp level correction device is configured to raise the headlamp level in response to determining that the cutoff line level is lower than the target line, and to lower the headlamp level when the cutoff line level is higher than the target line, thereby performing correction so that the cutoff line of the headlamp follows the target line level corresponding to the inter-vehicle distance.

2. The device for correcting the level of a headlamp according to claim 1, wherein: The license plate frame analysis device comprises: a distance calculation device configured to calculate an inter-vehicle distance to a preceding vehicle by utilizing a lateral length of the license plate frame image; and The reference height dividing device is configured to evenly divide the reference height of the rear area of the preceding vehicle where the license plate frame is spaced apart from the ground into heights of a plurality of unit areas using the vertical length of the license plate frame image.

3. The device for correcting the level of a headlamp according to claim 2, wherein: The distance calculation device is configured to calculate the inter-vehicle distance to the preceding vehicle by comparing the lateral length of the license plate frame image measured on the license plate frame image with the lateral length of a standard license plate to derive a proportional relationship therebetween.

4. The device for correcting the level of a headlamp according to claim 2, wherein: The license plate frame analyzing device is configured to correct a result of the inter-vehicle distance calculated by the distance calculating device by using an inter-vehicle distance to a preceding vehicle measured by a front radar sensor provided in the vehicle.

5. The device for correcting the level of a headlamp according to claim 2, wherein: The reference height dividing device is configured to: evenly divide the vertical length of the license plate frame appearing on the license plate frame image into a plurality of unit areas with the same height, and then evenly divide the reference height of the rear area of the preceding vehicle from the lower end of the license plate frame to the ground into the unit areas.

6. The device for correcting the level of a headlamp according to claim 2, wherein: The headlamp level correction device is configured to automatically perform correction to raise or lower the headlamp level so that the cutoff line of the headlamp reaches the target line when an automatic correction type headlamp level adjustment device that automatically adjusts the headlamp level is provided.

7. The device for correcting the level of a headlamp according to claim 6, wherein: When a headlamp level adjustment device of an automatic correction type is set, a main correction of the headlamp level is performed in advance based on the result recognized by the set sensor, and the headlamp level is further raised or lowered by the headlamp level correction device so that the cutoff line of the headlamp reaches the target line, thereby performing correction.

8. The device for correcting the level of a headlamp according to claim 2, wherein: The headlamp level correction device is configured to output a voice or a pop-up message requesting execution of correction to raise or lower the headlamp level so that the cutoff line of the headlamp reaches a target line when the switch type headlamp level adjustment device is set.

9. The apparatus for correcting headlight leveling according to claim 2, further comprising: A headlamp level indicator device is configured to simultaneously output a target line and a cutoff line on a front vehicle image when outputting a front image including a front vehicle on a display unit provided in a vehicle.

10. The device for correcting the level of a headlamp according to claim 9, wherein: The headlamp level indicator is configured to simultaneously output a preceding vehicle image, a cutoff line, and a target line on a windshield when the vehicle is provided with a head-up display.

11. A method for calibrating headlamp leveling, the method comprising: Using a controller, obtaining a license plate frame image from a preceding vehicle image captured by a camera disposed in a target vehicle; calculating, by a controller, an inter-vehicle distance from a preceding vehicle by using a lateral length of the license plate frame image, and dividing a reference height of a rear region of the preceding vehicle, where the license plate frame is spaced from the ground, into a plurality of unit regions by using a vertical length of the license plate frame image; using a controller, comparing a cutoff level at which light from the headlamp reaches a preceding vehicle with a target level as a preset ideal cutoff level, and determining the necessity of headlamp level correction; Correction is performed by the controller by raising the headlight level in response to determining that the cutoff level is below the target line and lowering the headlight level when the cutoff level is above the target line so that the cutoff line of the headlight follows the target line level corresponding to the inter-vehicle distance.

12. The method according to claim 11, wherein The analysis of the license plate frame includes: Using the controller, the vehicle distance to the preceding vehicle is calculated using the horizontal length of the license plate frame image; The controller evenly divides a reference height of a rear area of a preceding vehicle in which the license plate frame is spaced apart from the ground into a plurality of unit areas using a vertical length of the license plate frame image.

13. The method according to claim 12, wherein: The distance calculation includes: The controller calculates the inter-vehicle distance to the preceding vehicle by comparing the lateral length of the license plate frame image measured on the license plate frame image with the lateral length of a standard license plate to derive a proportional relationship thereof.

14. The method according to claim 12, wherein: The result of the inter-vehicle distance calculated during the distance calculation is corrected using the inter-vehicle distance to the preceding vehicle measured by a front radar sensor provided in the vehicle.

15. The method according to claim 12, wherein: The division of base height includes: The controller evenly divides the vertical length of the license plate frame appearing on the license plate frame image into a plurality of unit areas of equal height, and then evenly divides the reference height of the rear area of the preceding vehicle from the lower end of the license plate frame to the ground into the height of the unit areas.

16. The method according to claim 12, wherein: Headlamp leveling correction includes: When an automatic correction type headlamp level adjustment device that automatically adjusts the headlamp level is provided, correction to raise or lower the headlamp level is automatically performed using a controller so that the cutoff line of the headlamp reaches a target line.

17. The method according to claim 16, wherein When a headlamp level adjustment device of an automatic correction type is set, a main correction of the headlamp level is performed in advance based on the result recognized by the set sensor, and the headlamp level is further increased or decreased during the correction of the headlamp level so that the cutoff line of the headlamp reaches the target line, thereby performing correction.

18. The method according to claim 12, wherein: Headlamp leveling correction includes: When the switch type headlamp level adjustment device is provided, with the controller, a voice or a pop-up message requesting execution of correction to raise or lower the headlamp level so that the cutoff line of the headlamp reaches the target line is output.

19. The method of claim 12, further comprising: When a front image including a preceding vehicle is output on a display unit provided in the vehicle, the controller outputs a target line and a cutoff line simultaneously on the preceding vehicle image.

20. The method according to claim 12, wherein Indications of headlight level include: When the vehicle is provided with a head-up display, the controller is used to simultaneously output the image of the preceding vehicle, the cut-off line, and the target line on the windshield.

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