Apparatus and method for measuring luminance for controlling tunnel lighting

Abstract

The present disclosure relates to a technology for measuring luminance to control tunnel lighting, wherein an area ratio of luminance-calculated areas included in a tunnel entrance image is corrected on the basis of an installation position of an optical device, and a reference position luminance value for controlling tunnel lighting is calculated by reflecting a correction coefficient set on the basis of the installation position, surrounding environmental factors, and the like, in luminance measurement values of the corrected luminance-calculated areas.

Description

[Correction pursuant to Rule 26 23.10.2025] Luminance measuring device and method for tunnel lighting control

[0001] The present invention relates to a technology for measuring luminance to control tunnel lighting.

[0002] Tunnel lighting plays a crucial role in ensuring the safety of drivers and pedestrians. In particular, proper lighting control is essential at tunnel entrances and exits, as differences in brightness can lead to adaptation issues. During the day, the contrast between strong external natural light and the relatively low illumination inside the tunnel can cause a phenomenon (known as the Black Hole or White Hole Effect) that makes it difficult for drivers to maintain visibility, potentially increasing the risk of accidents.

[0003] Conventional tunnel lighting control systems use luminance meters to measure the luminance at the tunnel entrance and its surroundings, and by dynamically adjusting the lighting inside the tunnel based on the measurements, they mitigate the risk of accidents caused by the black hole or white hole effect.

[0004] However, since luminance meters have the characteristic of measuring luminance only within a specific field of view (FOV), it is difficult to determine the overall luminance distribution over a wide area, and luminance must be measured multiple times to analyze the difference in luminance over a wide space. As a result, conventional tunnel lighting control systems have the problem of being inefficient for controlling tunnel entrance lighting, which requires real-time measurement and control.

[0005] Furthermore, since luminance meters measure at a single point, collecting data from multiple locations is time-consuming. Additionally, due to the design characteristics of the meters, they cannot measure multiple points simultaneously and often require manual movement of the measurement point. Consequently, conventional tunnel lighting control systems face the problem of inefficiency in controlling tunnel entrance lighting because it is difficult to obtain fast and accurate luminance measurements in rapidly changing tunnel environments, such as those involving weather changes or vehicle movement.

[0006] Furthermore, because luminance meters utilize a single-point measurement method, real-time data processing and analysis are delayed. This limitation in real-time data processing makes it difficult to immediately reflect data in dynamic lighting control systems. Consequently, conventional tunnel lighting control systems suffer from reduced accuracy in tunnel entrance lighting control due to errors caused by time differences.

[0007] Furthermore, since luminance meters operate most accurately in static environments and are not suitable for dynamic changes, their accuracy deteriorates in road environments where there is a significant influence from moving objects, such as vehicle headlights and reflected light. Consequently, conventional tunnel lighting control systems suffer from low reliability in controlling lighting at tunnel entrances in environments with complex traffic conditions, such as tunnel entrances.

[0008] The matters described in the background technology above are intended to aid in understanding the background of the invention and may include matters that are not disclosed prior art.

[0009] The present invention is proposed in consideration of the above circumstances and aims to provide a luminance measuring device and method that calculates luminance by analyzing an image (or video) captured using an optical device, and calculates a reference position luminance value for controlling tunnel lighting by correcting the calculated luminance based on the installation location of the optical device and / or environmental factors around the tunnel.

[0010] To achieve the above objective, a luminance measuring device according to an embodiment of the present invention comprises a communication circuit for transmitting and receiving data for measuring the luminance of a tunnel entrance, a memory for storing commands and data for measuring the luminance of a tunnel entrance, and a processor configured to control the luminance measuring device to perform a plurality of operations by reading commands stored in the memory. The luminance measuring device detects a plurality of regions from a tunnel entrance image captured from the road shoulder according to the control of the processor, and calculates luminance correction values ​​corresponding to the luminance measurements of each region of the tunnel entrance image captured from a reference position by reflecting correction coefficients to the luminance measurements of the plurality of regions.

[0011] The luminance measuring device can be configured to set different correction coefficients in multiple areas according to the control of the processor.

[0012] The luminance measuring device can set a correction factor that, under the control of a processor, makes the correction amount of the area including the road area of ​​the tunnel entrance image among a plurality of areas greater than the correction amount of other areas.

[0013] The luminance measuring device can calculate area correction values ​​corresponding to the area of ​​each region of a tunnel entrance image taken at a reference location by correcting the area of ​​each of a plurality of regions based on a reference area ratio under the control of a processor, and can calculate a reference location luminance value corresponding to the luminance value of the tunnel entrance image taken at the reference location based on the luminance correction values ​​and the area correction values.

[0014] The correction factor can be set as a factor that varies the correction amount depending on the amount of cloud.

[0015] The luminance measuring device can set a correction factor such that, under the control of the processor, the correction amount when the amount of clouds is large is smaller than the correction amount when the amount of clouds is small.

[0016] The luminance measuring device sets a correction factor based on the amount of clouds calculated by the cloud amount measuring device under the control of the processor, and the cloud amount measuring device includes an illuminance sensor positioned to face the sky, and can estimate the amount of clouds by comparing the illuminance measurement value measured by the illuminance sensor with an illuminance reference value.

[0017] The luminance measuring device can set a correction coefficient that varies the correction amount based on the sun's azimuth according to the control of the processor, wherein the direction facing the tunnel entrance from the reference position is set as the first reference direction, the direction facing the tunnel entrance from the installation position is set as the second reference direction, and the correction coefficient can be set such that the correction amount when the sun's azimuth is closer to the first reference direction than the second reference direction is smaller than the correction amount when the sun's azimuth is closer to the second reference direction than the first reference direction.

[0018] The luminance measuring device can set a correction factor that varies the correction amount based on the sun's altitude under the control of a processor, and can set a correction factor such that the correction amount when the sun's altitude is high is smaller than the correction amount when the altitude is low.

[0019] To achieve the above-mentioned objective, a luminance measurement method according to an embodiment of the present invention is performed by a luminance measurement device and comprises the steps of: collecting a tunnel entrance image from an optical device installed on a road shoulder; detecting a plurality of regions from the tunnel entrance image; calculating luminance correction values ​​corresponding to the luminance measurement values ​​of each region of the tunnel entrance image taken at a reference position by reflecting a correction coefficient to the luminance measurement value of each of the plurality of regions; calculating area correction values ​​corresponding to the area of ​​each region of the tunnel entrance image taken at a reference position by correcting the area of ​​the plurality of regions based on a reference area ratio; and calculating a reference position luminance value corresponding to the luminance value of the tunnel entrance image taken at a reference position based on the luminance correction values ​​and the area correction values.

[0020] In the step of calculating luminance correction values, different correction coefficients can be set for multiple regions.

[0021] In the step of calculating luminance correction values, a correction factor can be set such that the correction amount of the area including the road area of ​​the tunnel entrance image among multiple areas is greater than the correction amount of other areas.

[0022] The correction factor can be set as a factor that varies the correction amount depending on the amount of cloud cover.

[0023] In the step of calculating luminance correction values, a correction factor can be set so that the correction amount when the amount of clouds is large is smaller than the correction amount when the amount of clouds is small.

[0024] In the step of calculating luminance correction values, the amount of clouds can be estimated by comparing the illuminance measurement value taken by an illuminance sensor positioned to face the sky with the illuminance reference value.

[0025] In the step of calculating luminance correction values, a correction factor can be set that varies the correction amount based on the sun's azimuth.

[0026] In the step of calculating luminance correction values, the direction facing the tunnel entrance from the reference position is set as the first reference direction, the direction facing the tunnel entrance from the installation position is set as the second reference direction, and a correction coefficient can be set such that the amount of correction when the sun's azimuth is closer to the first reference direction than the second reference direction is smaller than the amount of correction when the sun's azimuth is closer to the second reference direction than the first reference direction.

[0027] In the step of calculating luminance correction values, a correction factor can be set that varies the correction amount based on the sun's altitude, such that the correction amount when the sun's altitude is high is smaller than the correction amount when the altitude is low.

[0028] According to the present invention, the luminance measuring device and method have the effect of calculating an accurate reference position luminance value regardless of the installation position of the optical device by correcting the area ratio of luminance calculation regions included in the tunnel entrance image based on the installation position of the optical device.

[0029] In other words, the luminance measuring device and method correct the area ratio of luminance calculation regions in the tunnel entrance image acquired from an optical device installed on the side of the tunnel to correspond to the area ratio of luminance calculation regions in the tunnel image taken at the center of the tunnel, thereby having the effect of calculating an accurate reference position luminance value even if the optical device is not placed at the center of the tunnel but at a different location (right or left shoulder of the tunnel) according to the L20 standard.

[0030] In addition, the luminance measuring device and method calculate a reference position luminance value by reflecting a correction factor set based on solar data and cloud data, thereby calculating an accurate reference position luminance value and having the effect of minimizing errors in tunnel lighting control caused by environmental factors around the tunnel.

[0031] Through this, the luminance measuring device and method have the effect of minimizing the risk of accidents in the direction of the tunnel entrance caused by the black hole effect or the white hole effect.

[0032] FIGS. 1 and 2 are drawings for illustrating a tunnel lighting control system including an optical device installed according to L20 standards.

[0033] FIGS. 3 and 4 are drawings for illustrating a tunnel lighting control system including a luminance measuring device according to an embodiment of the present invention.

[0034] FIG. 5 is a drawing for explaining the configuration of a luminance measuring device according to an embodiment of the present invention.

[0035] FIG. 6 is a flowchart illustrating the operation of a luminance measuring device according to an embodiment of the present invention for calculating a reference position luminance value.

[0036] FIG. 7 is a drawing illustrating tunnel entrance images that change as the installation position of the optical device changes.

[0037] FIG. 8 is a flowchart illustrating the operation of a luminance measuring device according to an embodiment of the present invention to calculate a reference position luminance value by reflecting solar data.

[0038] FIG. 9 is a flowchart illustrating an example of an operation in which a luminance measuring device according to an embodiment of the present invention calculates a reference position luminance value by reflecting cloud data.

[0039] FIG. 10 is a flowchart illustrating an example of a process in which a luminance measuring device according to an embodiment of the present invention corrects a reference position luminance value using a luminance threshold value.

[0040] FIGS. 11 and 12 are flowcharts illustrating an example in which a luminance measuring device according to an embodiment of the present invention sets a correction coefficient for calculating a reference position luminance value by reflecting the amount of clouds.

[0041] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0042] The embodiments are provided to more fully explain the invention to those skilled in the art, and the following embodiments may be modified in various different forms, and the scope of the invention is not limited to the following embodiments. Rather, these embodiments are provided to make the disclosure more faithful and complete and to fully convey the spirit of the invention.

[0043] The terms used herein are for describing specific embodiments and are not intended to limit the invention. Additionally, the singular form in this specification may include the plural form unless the context clearly indicates otherwise. Terms such as “comprising,” “having,” and “having” in this application are intended to specify the presence of features, numbers, steps, actions, components, parts, or combinations thereof of the invention, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0044] The drawings are intended solely to facilitate an understanding of the concept of the present invention and should not be interpreted as limiting the scope of the invention. Additionally, relative thicknesses, lengths, or sizes in the drawings may be exaggerated for convenience and clarity of explanation.

[0045] The tunnel lighting control system measures the luminance at the tunnel entrance using the L20 standard. The L20 standard is a representative criterion for measuring luminance in tunnel lighting control systems and is an important concept related to the lighting design of the tunnel entrance.

[0046] The L20 standard defines a method for measuring luminance around a tunnel entrance and refers to the average luminance within a 20° field of view from the tunnel entrance as seen by a driver. This standard is used to evaluate the brightness conditions around the entrance as a driver approaches the tunnel, thereby enabling appropriate lighting control.

[0047] For example, referring to FIGS. 1 and 2, according to the L20 standard, the optical device (10) is positioned at a distance (D, interval) of approximately 160 m from the tunnel entrance (1) and at a height (H) of approximately 1.5 m. The optical device (10) photographs the tunnel from the front of the tunnel entrance (1) to generate an image of the tunnel entrance (see FIG. 2). Here, the positioning of the optical device (10) at a distance (D, interval) of approximately 160 m from the tunnel entrance (1) is an exemplary value set based on a speed limit of approximately 100 km / h, and the interval (D) may change if the speed limit standard changes.

[0048] The luminance measuring device (100) detects a luminance measuring area that is defined by the L20 standard among the tunnel entrance images and is a part of the area including the tunnel entrance (1). The luminance measuring device (100) detects a first area (A) which is the tunnel area, a second area (B) which is the surrounding environment, and a third area (C) which is the road surface in the luminance measuring area. Here, in the embodiment of the present invention, the first area (A) to the third area (C) are detected from the tunnel entrance image as an example, but the invention is not limited thereto and may be subdivided into four areas including the road area, the surrounding area, the sky area, and the tunnel entrance area, or subdivided into more areas.

[0049] The luminance measuring device (100) calculates the luminance measurement value of the first area (A), the luminance measurement value of the second area (B), and the luminance measurement value of the third area (C). The luminance measuring device (100) calculates the average value of the luminance measurements of the first area (A) to the third area (C) as the reference position luminance value for controlling the tunnel lighting (30).

[0050] According to the L20 standard, the optical device (10) must be installed at the standard location, but in the actual road environment, the standard location is the road where the vehicle travels, and since a vehicle with a height of 1.5m or more can travel on the road, it is difficult to install the optical device (10) at the standard location.

[0051] Considering these circumstances, in an actual road environment, the optical device (10) is not installed at a standard location but is installed on the shoulder (e.g., the right shoulder of the road) of the tunnel entrance (1).

[0052] Due to the difference in installation location, the tunnel entrance images generated by optical devices (10) installed at the reference location and the road shoulder, respectively, have different area ratios of the first area (A) to the third area (C) which serve as the basis for calculating the reference location luminance value, and thus cause the accuracy of the reference location luminance value to decrease, thereby reducing the control accuracy of the tunnel lighting (30).

[0053] Accordingly, the luminance measuring device (100) according to an embodiment of the present invention calculates a reference position luminance value corrected based on the reference position and installation position of the optical device (10), thereby preventing the accuracy of the reference position luminance value and the control accuracy of the tunnel lighting (30) from decreasing.

[0054] FIGS. 3 and FIGS. 4 are drawings for explaining a tunnel lighting control system including a luminance measuring device (100) according to an embodiment of the present invention.

[0055] Referring to FIGS. 3 and 4, the tunnel lighting control system comprises an optical device (10), a luminance measuring device (100), and a controller (20). Here, in FIG. 3, the luminance measuring device (100) is shown and described as being separate from the optical device (10), but is not limited thereto and may be integrated to form a single image-based sensor.

[0056] An optical device (10) is installed in front of the entrance of the tunnel, but is installed on the shoulder of the road at a set interval (G) away from the reference position in the lateral direction of the road (i.e., shoulder direction) to photograph the tunnel entrance (1). The optical device (10) generates a tunnel entrance image including the tunnel entrance (1) through the photograph. The optical device (10) transmits the tunnel entrance image to a luminance measuring device (100).

[0057] The luminance measuring device (100) analyzes the tunnel entrance image received from the optical device (10) to calculate a luminance measurement value, and calculates a reference position luminance value by reflecting a correction factor to the luminance measurement value. The luminance measuring device (100) transmits the reference position luminance value to the controller (20).

[0058] The controller (20) controls the brightness of the tunnel lights (30) installed in the direction of the tunnel entrance based on the reference position brightness value received from the brightness measuring device (100). The controller (20) controls the tunnel lights (30) to maintain a brightness determined according to the reference position brightness value.

[0059] Through this, the tunnel lighting control system minimizes the risk of accidents in the direction of the tunnel entrance caused by the black hole or white hole effect.

[0060] Referring to FIG. 5, a luminance measuring device (100) according to an embodiment of the present invention is configured to include a communication circuit (120), a memory (140), and a processor (160).

[0061] The communication circuit (120) exchanges data with an external device. According to embodiments, the communication circuit (120) may exchange data with the optical device (10) and the controller (20) according to a wired communication protocol or a wireless communication protocol.

[0062] The memory (140) can store data necessary for the operation of the luminance measuring device (100). According to embodiments, the memory (140) can store a program including a plurality of instructions for performing various operations performed by the luminance measuring device (100).

[0063] Additionally, the memory (140) can store data transmitted from or to be transmitted from the outside. According to embodiments, the memory (140) can store a tunnel entrance image received from the optical device (10) and a reference position brightness value to be transmitted to a controller (20) for controlling the tunnel lighting (30).

[0064] The processor (160) can control the overall operation of the luminance measuring device (100). According to embodiments, the luminance measuring device (100) has a computational processing function under the control of the processor (160), executes an application stored in memory (140), and can perform a plurality of operations according to instructions included in the application. For example, the processor (160) can perform the above-mentioned plurality of operations by controlling the luminance measuring device (100).

[0065] According to embodiments, some functions of the memory (140) may be separated and additionally or substantially implemented as part of the processor (160) of the luminance measuring device (100).

[0066] FIG. 6 is a flowchart illustrating the operation of a luminance measuring device (100) according to an embodiment of the present invention to calculate a reference position luminance value.

[0067] First, the luminance measuring device (100) stores a correction coefficient table in which correction coefficients are matched by date and time. An example of the correction coefficient table is that it is generated by calculating a reference position luminance value from a tunnel entrance image generated at a first time point from optical devices (10) installed at a reference position and a road shoulder, respectively, calculating the difference between the two reference position luminance values ​​as a correction coefficient, and linking the correction coefficient to the date and / or time of the first time point.

[0068] The luminance measuring device (100) stores a reference area ratio, which is the area ratio of the first area (A) to the third area (C) included in the tunnel entrance image taken at a reference position.

[0069] Referring to FIG. 6, the luminance measuring device (100) detects a correction factor and a reference area ratio corresponding to the current time point (S110). The luminance measuring device (100) detects a correction factor corresponding to the current time point from a correction factor table.

[0070] The luminance measuring device (100) detects the first region (A) to the third region (C) from the tunnel entrance image received from the optical device (10) (S120).

[0071] The luminance measuring device (100) calculates a first luminance measuring value, which is the luminance of a first area (A) of the tunnel entrance image, a second luminance measuring value, which is the luminance of a second area (B), and a third luminance measuring value, which is the luminance of a third area (C) (S130).

[0072] In step S130, the luminance measuring device (100) converts the RGB value or grayscale value of each pixel included in the first area (A) into physical luminance, and calculates the average value of the physical luminance of all pixels included in the first area (A) as the first luminance measuring value.

[0073] In step S130, the luminance measuring device (100) converts the RGB value or grayscale value of each pixel included in the second area (B) into physical luminance, and calculates the average value of the physical luminance of all pixels included in the second area (B) as the second luminance measuring value.

[0074] In step S130, the luminance measuring device (100) converts the RGB value or grayscale value of each pixel included in the third area (C) into physical luminance, and calculates the average value of the physical luminance of all pixels included in the third area (C) as the third luminance measuring value.

[0075] The luminance measuring device (100) calculates the first luminance correction value, the second luminance correction value, and the third luminance correction value by applying a correction coefficient to the first luminance measurement value, the second luminance measurement value, and the third luminance measurement value, respectively (S140).

[0076] The luminance measuring device (100) calculates a first area measurement value, which is the area of ​​a first region (A) included in the tunnel entrance image, a second area measurement value, which is the area of ​​a second region (B), and a third area measurement value, which is the area of ​​a third region (C) (S150).

[0077] The luminance measuring device (100) calculates the first area correction value, the second area correction value, and the third area correction value by correcting the first area measurement value, the second area correction value, and the third area correction value by reflecting the reference area ratio (S160).

[0078] Referring to FIG. 7, the tunnel image captured by the optical device (10, hereinafter, the roadside optical device (10)) installed on the roadside and the tunnel image captured by the optical device (10, hereinafter, the reference optical device (10)) installed at the reference position differ in the area of ​​the first region (A, A') to the third region (C, C'), which is important for calculating the reference position luminance value, so the accurate reference position luminance value cannot be calculated, and consequently, the accuracy of the lighting control is inevitably reduced. Accordingly, the luminance measuring device (100) generates a first area correction value to a third area correction value by correcting the area ratio so that the first region (A') to the third region (C') included in the tunnel entrance image of the side optical device (10) corresponds to the first region (A) to the third region (C) included in the tunnel entrance image of the front optical device (10).

[0079] The luminance measuring device (100) calculates a reference position luminance value using the first to third luminance correction values, and the first area correction value and the third area correction value (S170).

[0080] In step S170, the luminance measuring device (100) calculates the reference position luminance value using the following mathematical formula 1 as an example. In the following mathematical formula 1, Lt is the reference position luminance value, L1 is the first luminance correction value, L2 is the second luminance correction value, L3 is the third luminance correction value, S1 is the first area correction value, S2 is the second area correction value, and S3 is the third area correction value.

[0081]

[0082] Through the above-described operation, the luminance measuring device (100) corrects the reference position luminance value based on the road shoulder to the reference position luminance value based on the reference position.

[0083] In other words, the luminance measuring device (100) calculates the reference position luminance value at the reference position using the tunnel entrance image generated by the optical device (10) installed on the road shoulder.

[0084] Meanwhile, luminance is subject to many variables depending on the surrounding environment, such as the relative position of the sun and weather conditions. As described above, since the luminance measuring device (100) calculates the reference position luminance value based on a correction coefficient generated through actual measurement, it fails to reflect surrounding environmental factors such as the sun and weather, resulting in an error in the reference position luminance value and consequently reducing the accuracy of lighting control.

[0085] Accordingly, the luminance measuring device (100) can calculate a reference position luminance value by reflecting a correction factor based on surrounding environmental factors. The luminance measuring device (100) corrects the correction factor based on solar data and / or weather data that affect luminance, and calculates the reference position luminance value using the corrected correction factor.

[0086] First, the operation of the luminance measuring device (100) to calculate a reference position luminance value by reflecting solar data is explained.

[0087] Since the luminance value of the tunnel entrance (1) can vary significantly depending on the position of the sun, the luminance measuring device (100) calculates an accurate reference position luminance value by correcting for the influence of direct sunlight, reflected light, shading, etc., according to the altitude and azimuth of the sun in the luminance measurement of the tunnel entrance (1).

[0088] The luminance measuring device (100) detects the position of the sun at the corresponding time and calculates a correction factor based on the relative altitude and azimuth of the sun relative to the tunnel direction (or tunnel entrance (1)).

[0089] Accordingly, the luminance measuring device (100) enables stable lighting design and control by minimizing the occurrence of errors caused by changes in the relative position of the tunnel entrance (1) and the sun. Through this, the luminance measuring device (100) enables stable lighting design and control by minimizing the occurrence of errors caused by changes in the relative position of the tunnel entrance (1) and the sun.

[0090] FIG. 8 is a flowchart illustrating the operation of a luminance measuring device (100) according to an embodiment of the present invention to calculate a reference position luminance value by reflecting solar data.

[0091] Referring to FIG. 8, the luminance measuring device (100) calculates the altitude and azimuth of the sun (S210). The luminance measuring device (100) calculates the altitude and azimuth (or azimuth angle) of the sun using the current date and current time.

[0092] The luminance measuring device (100) sets a correction factor based on the altitude of the sun (S220).

[0093] When the sun's altitude increases, the directionality of the reflected light decreases, and the difference in luminance measured according to the position of the optical device (10) decreases, so the difference between the luminance measured at the reference position and the luminance measured at the installation position decreases. On the other hand, when the sun's altitude decreases, the directionality of the reflected light increases, so the difference in luminance measured according to the position of the optical device (10) increases, and the difference between the luminance measured at the reference position and the luminance measured at the installation position increases.

[0094] Accordingly, in step S230, the luminance measuring device (100) sets a correction factor such that the correction amount when the sun's altitude is high is smaller than the correction amount when the altitude is low. For example, the luminance measuring device (100) is set to a factor such that the correction amount when the sun's altitude is 30° is smaller than the correction amount when the sun's altitude is 20°.

[0095] The luminance measuring device (100) sets a correction factor based on the sun's orientation (S230).

[0096] In step S230, the luminance measuring device (100) sets the direction of looking toward the tunnel entrance (1) from the reference position as the first reference direction, and sets the direction of looking toward the tunnel entrance (1) from the installation position of the luminance measuring device (100) as the second reference direction.

[0097] In step S230, the luminance measuring device (100) sets a correction factor such that the correction amount when the sun's orientation is closer to the first reference direction than the second reference direction is smaller than the correction amount when the sun's orientation is closer to the second reference direction than the first reference direction.

[0098] In steps S220 and S230, since the altitude and azimuth of the sun are relative information for each region, the luminance measuring device (100) can set different correction coefficients for each region in the first region (A) to the third region (C).

[0099] In step S230, the third area (C), which is the road surface, has a greater influence of sunlight on luminance compared to the first area (A), which is the tunnel area, and the second area (B), which is the surrounding environment. Accordingly, the luminance measuring device (100) sets a correction coefficient such that the correction amount of the third area (C) is greater than the correction amount of the first area (A) and the correction amount of the second area (B).

[0100] Next, the operation of the luminance measuring device (100) to calculate a reference position luminance value by reflecting weather data is described.

[0101] Clouds are an important factor affecting the level of natural light because they can scatter or block sunlight, thereby significantly changing the brightness of the surroundings. In particular, clouds are important information for optimizing brightness adjustment in external environments such as tunnel entrances (1).

[0102] If there are many clouds, sunlight becomes almost diffused light, reducing the difference between the luminance measurement at the reference location and the luminance measurement at the installation location, and if there are few clouds, the difference between the luminance measurement at the reference location and the luminance measurement at the installation location increases.

[0103] Accordingly, the luminance measuring device (100) calculates a correction factor based on cloud data and calculates a reference position luminance value reflecting the correction factor, thereby minimizing the occurrence of errors caused by changes in cloud data and enabling stable lighting design and control.

[0104] FIG. 9 is a flowchart illustrating an example of an operation in which a luminance measuring device (100) according to an embodiment of the present invention calculates a reference position luminance value by reflecting cloud data.

[0105] Referring to FIG. 9, the luminance measuring device (100) collects cloud data (S310). The luminance measuring device (100) collects cloud data from satellite data, weather sensors, weather forecast data, etc. The luminance measuring device (100) collects cloud data including the amount of clouds.

[0106] The luminance measuring device (100) sets a correction factor based on cloud data (S320).

[0107] In step S320, the luminance measuring device (100) sets a correction factor such that the correction amount when the amount of cloud is large is smaller than the correction amount when the amount of cloud is small.

[0108] In step S320, the luminance measuring device (100) may set different correction coefficients for each region in the first region (A) to the third region (C).

[0109] Meanwhile, the luminance measuring device (100) may correct the luminance measurement value using a luminance threshold value without using information such as solar data and cloud data.

[0110] As an example, the luminance measuring device (100) stores a luminance threshold table including luminance thresholds by date and / or time period, calculates a correction coefficient by comparing the current luminance measuring value and the luminance threshold at the current time, and corrects the luminance measuring value by reflecting the correction coefficient. At this time, the luminance measuring device (100) calculates a correction coefficient that makes the amount of correction smaller when the luminance measuring value is lower than when the luminance measuring value is higher, based on the luminance threshold for that time (e.g., 70% of the luminance when clear).

[0111] Here, the luminance threshold is a value calculated using luminance measurements taken by date and / or time period, and is exemplified by being set as the average value of multiple luminance measurements taken on the same date and / or time period.

[0112] For example, referring to FIG. 10, the luminance measuring device (100) detects a luminance threshold value at the current time (S410).

[0113] Before step S410, the luminance measuring device (100) analyzes a tunnel entrance image generated in cloudless clear weather to calculate a luminance measurement value, and sets and stores approximately 70% of the luminance measurement value as the luminance threshold value for the corresponding time (date, time).

[0114] Before step S410, since the area with the greatest influence on brightness among the tunnel entrance images is the road area, the third area (C), the brightness measuring device (100) may set and store approximately 70% of the third brightness measurement value, which is the brightness of the third area (C), as the brightness threshold.

[0115] The luminance measuring device (100) analyzes the tunnel entrance image at the current time and calculates the current luminance measurement value (S420).

[0116] In step S420, if a luminance threshold is set based on a third luminance measurement value, the luminance measurement device (100) can calculate the third luminance measurement value, which is the luminance of the third region (C) of the tunnel entrance image, as the current luminance measurement value.

[0117] If the current luminance measurement value is greater than or equal to the luminance threshold value (S430; yes), the luminance measuring device (100) sets the first coefficient as a correction coefficient (S440).

[0118] In step S440, the luminance measuring device (100) may set different correction coefficients for each region in the first region (A) to the third region (C).

[0119] If the current luminance measurement value is less than the luminance threshold value (S430; No), the luminance measuring device (100) sets a second coefficient as a correction coefficient (S450).

[0120] In step S450, the luminance measuring device (100) may set different correction coefficients for each region in the first region (A) to the third region (C). Here, the second coefficient is exemplified as a coefficient that makes the correction amount of the luminance measurement value smaller than the first coefficient.

[0121] The luminance measuring device (100) calculates a luminance correction value that reflects a correction factor (S460).

[0122] In step S460, the luminance measuring device (100) can calculate a first luminance correction value by reflecting a correction coefficient to a first luminance measurement value, calculate a second luminance correction value by reflecting a correction coefficient to a second luminance measurement value, and calculate a third luminance correction value by reflecting a correction coefficient to a third luminance measurement value.

[0123] As it is practically difficult to collect cloud data and luminance threshold tables as described above, in an embodiment of the present invention, the amount of clouds can be measured through illuminance sensing or image processing, and a correction factor can be set based on the measured amount of clouds.

[0124] Referring to FIGS. 11 and 12, the luminance measuring device (100) can set a correction factor based on the amount of clouds collected through the cloud amount measuring device (200). Here, the cloud amount measuring device (200) may be installed on the luminance measuring device (100) or installed adjacent to the luminance measuring device (100) at a certain distance from the luminance measuring device (100).

[0125] The cloud amount measuring device (200) may be composed of an illuminance meter. The cloud amount measuring device (200) is installed facing the sky and measures the illuminance of the sky to generate an illuminance measurement value. The cloud amount measuring device (200) estimates the amount of clouds based on the illuminance measurement value and the illuminance reference value. Since the illuminance reference value is set as the current illuminance when there are no clouds, the cloud amount measuring device (200) must accurately set the illuminance reference value to accurately measure the amount of clouds.

[0126] However, in order to set an illuminance reference value, the illuminance in a cloudless state must be measured at the same time and under environmental conditions, which is practically difficult to implement. As a result, the cloud amount measuring device (200) may find it difficult to ensure an accuracy above a certain level for the cloud amount measured using the illuminance measurement value of the illuminance meter.

[0127] Accordingly, in an embodiment of the present invention, the amount of clouds can be measured by image processing a sky image taken of the sky.

[0128] For example, referring to FIG. 12, the cloud amount measuring device (200) may be composed of a second optical device positioned to face the sky, unlike an optical device (10) positioned to face the tunnel. Here, the second optical device may be formed integrally with the optical device (10). The second optical device captures the sky to generate a sky image and calculates the cloud amount through image processing of the sky image.

[0129] The luminance measuring device (100) sets a correction factor based on the amount of clouds calculated through image processing in the cloud amount measuring device (200), and sets a correction factor such that the amount of correction when the amount of clouds is large is smaller than the amount of correction when the amount of clouds is small.

[0130] The foregoing description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are intended to explain, not limit, the technical concept of the present invention, and the scope of the technical concept of the present invention is not limited by these embodiments. The scope of protection of the present invention shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of the present invention.

Claims

1. In a luminance measuring device, A communication circuit for transmitting and receiving data to measure the brightness of a tunnel entrance; Memory for storing commands and data for measuring the luminance of the tunnel entrance; and It includes a processor configured to control the luminance measuring device to perform multiple operations by reading instructions stored in the memory, and The above luminance measuring device, under the control of the processor, A luminance measuring device that detects multiple regions from a tunnel entrance image taken from a roadside and calculates luminance correction values ​​corresponding to the luminance measurements of each region of the tunnel entrance image taken from a reference position by reflecting a correction coefficient to the luminance measurements of the multiple regions.

2. In Paragraph 1, The above luminance measuring device, under the control of the processor, A luminance measuring device configured to set different correction coefficients for the above plurality of regions.

3. In Paragraph 1, The above luminance measuring device, under the control of the processor, A luminance measuring device that sets a correction factor to make the correction amount of the area including the road area of ​​the tunnel entrance image among the plurality of areas above greater than the correction amount of other areas.

4. In Paragraph 1, The above luminance measuring device, under the control of the processor, Area correction values ​​corresponding to the area of ​​each of the plurality of regions are calculated by correcting the area of ​​each region of the tunnel entrance image when taken at the reference location based on the reference area ratio, and A luminance measuring device that calculates a reference position luminance value corresponding to the luminance value of a tunnel entrance image taken at the reference position based on the above luminance correction values ​​and the above area correction values.

5. In Paragraph 4, A luminance measuring device in which the above correction factor is set as a factor that varies the correction amount depending on the amount of clouds.

6. In Paragraph 5, The above luminance measuring device, under the control of the processor, A luminance measuring device that sets a correction factor such that the correction amount when the amount of cloud is large is smaller than the correction amount when the amount of cloud is small.

7. In Paragraph 4, The above luminance measuring device, under the control of the processor, A correction factor is set based on the amount of cloud calculated by the cloud amount measuring device, and The cloud amount measuring device described above includes an illuminance sensor positioned to face the sky, and a luminance measuring device that estimates the amount of clouds by comparing the illuminance measurement value measured by the illuminance sensor with an illuminance reference value.

8. In Paragraph 1, The above luminance measuring device, under the control of the processor, Set a correction factor that varies the correction amount based on the sun's azimuth, The direction facing the tunnel entrance from the reference position is set as the first reference direction, and The direction facing the tunnel entrance from the installation location is set as the second reference direction, and A luminance measuring device that sets a correction coefficient such that the correction amount when the sun's azimuth is closer to the first reference direction than the second reference direction is smaller than the correction amount when the sun's azimuth is closer to the second reference direction than the first reference direction.

9. In Paragraph 1, The above luminance measuring device, under the control of the processor, Set a correction factor that varies the correction amount based on the sun's altitude, A luminance measuring device that sets a correction factor such that the correction amount when the sun's altitude is high is smaller than the correction amount when the altitude is low.

10. A method for measuring luminance performed by a luminance measuring device, A step of collecting an image of the tunnel entrance from an optical device installed on the roadside; A step of detecting a plurality of regions from the above tunnel entrance image; A step of calculating luminance correction values ​​corresponding to the luminance measurements of each region of the tunnel entrance image taken at a reference position by reflecting a correction coefficient to each of the luminance measurements of the plurality of regions above; A step of calculating area correction values ​​corresponding to the area of ​​each region of the tunnel entrance image taken at the reference position by correcting the area of ​​the plurality of regions based on the reference area ratio; and A luminance measurement method comprising the step of calculating a reference position luminance value corresponding to the luminance value of a tunnel entrance image taken at the reference position based on the above luminance correction values ​​and the above area correction values.

11. In Paragraph 10, In the step of calculating the above luminance correction values, A luminance measurement method for setting different correction coefficients in the above-mentioned plurality of regions.

12. In Paragraph 10, In the step of calculating the above luminance correction values, A luminance measurement method for setting a correction factor that makes the correction amount of an area including the road area of ​​the tunnel entrance image among the above plurality of areas greater than the correction amount of other areas.

13. In Paragraph 10, The above correction factor is a luminance measurement method in which the correction amount is set differently depending on the amount of cloud cover.

14. In Paragraph 13, In the step of calculating the above luminance correction values, A luminance measurement method that sets a correction factor such that the correction amount when the amount of cloud is large is smaller than the correction amount when the amount of cloud is small.

15. In Paragraph 13, In the step of calculating the above luminance correction values, A luminance measurement method that estimates the amount of clouds by comparing an illuminance measurement value measured by an illuminance sensor positioned to face the sky with an illuminance reference value.

16. In Paragraph 10, In the step of calculating the above luminance correction values, A luminance measurement method that sets a correction factor with a different correction amount based on the sun's azimuth.

17. In Paragraph 16, In the step of calculating the above luminance correction values, The direction facing the tunnel entrance from the reference position is set as the first reference direction, and The direction facing the tunnel entrance from the installation location is set as the second reference direction, and A luminance measurement method for setting a correction coefficient such that the correction amount when the sun's orientation is closer to the first reference direction than the second reference direction is smaller than the correction amount when the sun's orientation is closer to the second reference direction than the first reference direction.

18. In Paragraph 10, In the step of calculating the above luminance correction values, Set a correction factor that varies the correction amount based on the sun's altitude, A luminance measurement method for setting a correction factor such that the correction amount when the sun's altitude is high is smaller than the correction amount when the altitude is low.

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