Controller, control system, and control method

Abstract

To provide a controller, control system, and control method making it possible to automatically implement anti-glare related control without requiring a light quantity sensor in a mirror, and achieve appropriate anti-glare performance.SOLUTION: A controller 10 includes a control unit 13 that acquires a captured image based on a result of imaging by a camera 11 configured to capture a rear view of a vehicle, and that determines a mirror reflectance, which is a reflectance of a mirror, on the basis of a luminance status of the captured image. The reflectance of the mirror is determined based on the luminance status of the captured image based on the imaging result of the camera 11 without using a detection result of a light quantity sensor included in the mirror.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a control device, a control system, and a control method, and in particular, is suitable for use in a control device that is provided in a vehicle and performs processing related to a mirror configured to change the reflectance, a control system that includes the control device and the mirror, and a control method using the control device. [Background technology]

[0002] Conventionally, a mirror (so-called rearview mirror) provided in the passenger compartment of a vehicle is known that is equipped with an anti-glare function. Patent Document 1 discloses the following technology regarding this type of mirror. That is, the mirror 2 according to Patent Document 1 is provided with an ambient light amount sensor 31 that detects the amount of light incident from the front of the vehicle, and a rear light amount sensor 32 that detects the amount of light incident from the rear of the vehicle. The mirror 2 is controlled so that the mirror 2 is automatically in an anti-glare state when the amount of light detected by the rear light amount sensor 32 is greater than the amount of light detected by the ambient light amount sensor 31. Patent Document 1 discloses the above technology. According to this configuration, when the light of the headlights of a following vehicle is incident on the mirror 2 during night driving, the mirror 2 is automatically in an anti-glare state, thereby improving the convenience of the driver. As in Patent Document 1, it is widely practiced to provide a mirror with two sensors that detect the amount of light incident from the front and rear of the vehicle, and to automatically control the anti-glare based on the difference in the amount of light detected by these sensors.

[0003] Patent Document 2 describes a technology that sets a following vehicle anti-glare period during which anti-glare is expected to be necessary based on the results of imaging by a backup camera 4 that captures the area behind the vehicle, and reduces the brightness of the image captured by the backup camera 4 during this period. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-173460 A [Patent Document 2] Patent Publication No. 2021-172243 Summary of the Invention [Problem to be solved by the invention]

[0005] The mirror of Patent Document 1, which controls anti-glare using two light quantity sensors installed on the mirror, has the following problems. That is, the mirror needs to be designed taking into account the presence of the two light quantity sensors, and the presence of the two light quantity sensors on the mirror restricts the design. In addition, since there is usually indoor lighting near the mirror, it is necessary to design the mirror taking into account the influence of light from the indoor lighting when the indoor lighting is turned on, which makes the design difficult. Due to the above circumstances, it has been desired to automatically control anti-glare without installing a light quantity sensor on the mirror. However, it would be counterproductive if the appropriateness of anti-glare was lost due to not installing a light quantity sensor on the mirror, and it is desired to realize appropriate anti-glare that suppresses the driver from feeling excessive glare. Automatic anti-glare control

[0006] The present invention has been made to solve such problems, and aims to enable automatic control of anti-glare without installing a light quantity sensor on the mirror, and to achieve more appropriate anti-glare. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present invention obtains a captured image based on the results of shooting with a camera that photographs the rear of the vehicle, and determines the mirror reflectance, which is the reflectance of the mirror, based on the brightness conditions of the captured image. Effect of the Invention

[0008] The degree of reflectance to be applied to the mirror to realize appropriate anti-glare is determined according to the brightness of the real environment behind the vehicle. Also, the brightness of the image captured by the camera capturing the rear of the vehicle changes according to the brightness of the real environment behind the vehicle. In this case, it is possible to grasp the mirror reflectance required to realize appropriate anti-glare from the brightness of the captured image. In view of the above, according to the present invention configured as above, the mirror reflectance is determined based on the brightness of the image captured by the camera capturing the rear of the vehicle, not on the light quantity sensor provided on the mirror, so that it is possible to automatically control anti-glare without providing a light quantity sensor on the mirror, and to realize appropriate anti-glare. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is an external view of a mirror according to an embodiment. [Diagram 2] FIG. 2 is a block diagram showing an example of a functional configuration of a control device according to an embodiment. [Diagram 3] 5 is a flowchart illustrating an example of an operation of a control device according to an embodiment. [Figure 4] 5 is a flowchart illustrating an example of an operation of a control device according to an embodiment. [Diagram 5] FIG. [Figure 6] FIG. 13 is a diagram showing a captured image together with a histogram of the luminance of each pixel on a line of interest. [Figure 7] 5 is a flowchart illustrating an example of an operation of a control device according to an embodiment. [Figure 8] FIG. 13 is a diagram showing relationship definition information. [Figure 9] FIG. 13 is a diagram showing a modified example of the line of interest. [Figure 10] 10 is a flowchart showing an example of the operation of the control device according to the first modified example. [Figure 11] FIG. [Figure 12] 11A and 11B are diagrams used to explain a maximum average luminance difference derivation process. [Figure 13] FIG. 13 is a diagram showing a modified example of a group of target lines. [Figure 14] FIG. 13 is a diagram showing a modified example of the block configuration. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an external view of a mirror 1 according to this embodiment. The mirror 1 is a so-called room mirror provided in a vehicle interior 3 of a vehicle 2. The mirror 1 is provided at a position close to a windshield 4 on the ceiling of the vehicle interior 3. The mirror 1 is used at least for the driver to check the rear. Here, in a situation where the vehicle 2 is traveling at night, traveling in a tunnel, or in other situations where the outside of the vehicle 2 is dark, the headlights of a following vehicle may enter the mirror 1. In addition, light may enter the mirror 1 from the rear of the vehicle 2 due to some reason. If no measures are taken against this, there may be a case where the driver feels excessive glare. In light of this, the mirror 1 according to this embodiment is configured to be able to change its reflectance and has an automatic anti-glare function. The automatic anti-glare function is a function that automatically changes the reflectance of the mirror 1 to suppress the glare felt by the driver. The automatic anti-glare function will be described in detail later.

[0011] Fig. 2 is a block diagram showing an example of the functional configuration of the control device 10 according to this embodiment. As shown in Fig. 2, a mirror 1 and a camera 11 are connected to the control device 10. The control device 10, the mirror 1, and the camera 11 constitute a control system 12 according to this embodiment.

[0012] As shown in FIG. 3, the control device 10 has a control unit 13 and a memory unit 14 as functional components. The control unit 13 has a processing unit and a primary storage device. The processing unit is a device having an information processing function and has a CPU. The CPU has a central control unit, an arithmetic unit, a register, and a cache memory. The primary storage device has a DRAM and other volatile memories. The control unit 13 executes processing by the processing unit reading out a program stored in the memory unit 14 into the primary storage device and executing it. In other words, the control unit 13 executes processing by cooperation between hardware and software. The memory unit 14 has a hard disk drive (which may be another magnetic storage device), a ROM, a flash memory, and other non-volatile memories. The memory unit 14 stores data in the non-volatile memory.

[0013] The camera 11 is an imaging device that captures images of the rear of the vehicle 2. The camera 11 is provided in a position that allows it to capture images of the rear of the vehicle 2. For example, the camera 11 is provided on the rear bumper, roof top, or license plate outside the vehicle, or on the upper inside of the rear window inside the vehicle. The camera 11 continues to capture images at least while the driver is driving (regardless of whether the vehicle 2 is stopped or not), and outputs captured images F based on the capture results to the control unit 13 at a predetermined frame rate (for example, 60 fps).

[0014] The mirror 1 includes an optical device 15 including a liquid crystal panel. The control unit 13 can change the reflectance of the mirror 1 by changing the transmittance of the liquid crystal panel of the optical device 15 via a drive circuit (not shown). Hereinafter, the reflectance of the mirror 1 is particularly referred to as the "mirror reflectance." In this embodiment, the control unit 13 can change the mirror reflectance between 0 and 100%.

[0015] Next, the operation of the control device 10 with respect to the automatic anti-glare function will be described. Fig. 3 is a flowchart showing an example of the operation of the control device 10, showing the processing executed by the control device 10 with respect to the automatic anti-glare function while the vehicle 2 is traveling (regardless of whether the vehicle 2 is stopped). The flowchart FA in Fig. 3 shows a control method by the control device 10. As described above, the camera 11 outputs the captured image F based on the shooting result at a predetermined frame rate to the control unit 13. The control unit 13 executes the processing shown in the flowchart FA every time it acquires the captured image F at the predetermined frame rate.

[0016] 3, the control unit 13 inputs and acquires the captured image F from the camera 11 (step SA1). In this embodiment, the captured image F is image data in which pixels G (FIG. 5) holding RGB gradation values ​​(hereinafter referred to as "pixel values") are arranged in a matrix. In step SA1, the captured image F is expanded in an image buffer that the control unit 13 can refer to.

[0017] Next, the control unit 13 executes a local degree derivation process (step SA2). The local degree derivation process is a process in which the control unit 13 derives a "local degree" that is a degree to which a condition in which the rear of the vehicle is locally bright is satisfied based on the brightness state of the captured image F. In this embodiment, the control unit 13 derives, as the local degree, a "maximum brightness difference" that is a difference in brightness between a pixel with the highest brightness and a pixel with the lowest brightness among pixels on a line of interest that is a line extending in a predetermined direction on the captured image F. The local degree derivation process will be described in detail below.

[0018] The flowchart FB in Fig. 4 is a flowchart showing details of the local degree derivation process. As shown in Fig. 4, in the local degree derivation process, the control unit 13 first executes a target line determination process (step SB1). The target line determination process is a process for determining a target line (described later). The target line determination process will be described in detail below.

[0019] FIG. 5 is a diagram showing a photographed image F in a manner suitable for explanation. The photographed image F is configured by arranging pixels G in a matrix in the x-axis direction (the direction corresponding to the horizontal direction of the photographed landscape) and the y-axis direction (the direction corresponding to the vertical direction of the photographed landscape). In FIG. 5, the upper left corner of the photographed image F is the origin, the direction toward the right in the x-axis direction is the + side of the x-axis, the direction toward the left is the - side of the x-axis, the direction toward the bottom in the y-axis direction is the + side of the y-axis, and the direction toward the top is the - side of the y-axis. This is the same for FIGS. 6, 9, 11-14. In this embodiment, as shown in FIG. 5, a line of pixels G in one row extending from one end to the other in the x-axis direction in the photographed image F is defined as an "x-axis line". The photographed image F is configured by a predetermined number of x-axis lines.

[0020] In the process of step SB1, the control unit 13 identifies the pixel with the highest brightness (hereinafter referred to as the "highest brightness pixel") among the pixels constituting the captured image F. The control unit 13 derives the brightness of a pixel from the pixel value of that pixel using a predetermined calculation formula. In this embodiment, the brightness is assumed to take values ​​in the range of 0 to 255 pt (pt is a unit added for convenience). Then, when there is one highest brightness pixel, or when all the highest brightness pixels belong to one x-axis line, the control unit 13 determines the x-axis line including the highest brightness pixel as the line of interest.

[0021] On the other hand, when there are multiple maximum brightness pixels and they are on multiple different x-axis lines, the control unit 13 determines the line of interest in the following manner. That is, when the control unit 13 can narrow down the x-axis line containing the largest number of maximum brightness pixels (hereinafter referred to as the "most numerous x-axis line") to one, it determines the most numerous x-axis line as the line of interest. For example, referring to FIG. 5, it is assumed that pixels G-1, G-2, and G-3 are the maximum brightness pixels. Pixels G-2 and G-3 belong to the same x-axis line. In this case, the control unit 13 determines the x-axis line containing pixels G-2 and G-3 as the line of interest.

[0022] On the other hand, when the most frequent x-axis line cannot be narrowed down to one, in other words, when there are two or more most frequent x-axis lines, the control unit 13 determines the most frequent x-axis line including the highest brightness pixel closest to the specific position as the attention line among the most frequent x-axis lines. In this embodiment, the specific position is the center position of the photographed image F. For example, referring to FIG. 5, it is assumed that pixels G-1, G-4, and G-5 are the highest brightness pixels. In this case, the control unit 13 determines the x-axis line including pixel G-1 as the attention line. This is because, among pixels G-1, G-4, and G-5, pixel G-1 is closest to the specific position (=the center position of the photographed image F). Note that the specific position is set to the "center position of the photographed image F" assuming the position of the headlights of the following vehicle. In light of this, the specific position may be a position corresponding to the "position of the headlights of the following vehicle" and different from the "center position of the photographed image F".

[0023] In addition, there may be a case where there are multiple most-populated x-axis lines including the highest-luminance pixel closest to the specific position. In this case, the control unit 13 determines an arbitrary most-populated x-axis line among the multiple most-populated x-axis lines including the highest-luminance pixel closest to the specific position as the line of interest.

[0024] As described above, in the target line determination process of step SB1, the control unit 13 determines the target line.

[0025] After the process of step SB1, the control unit 13 executes a maximum brightness difference derivation process (step SB2). In the maximum brightness difference derivation process, the control unit 13 derives the brightness difference between the pixel G with the highest brightness and the pixel G with the lowest brightness among the pixels G on the line of interest determined in step SB1, and sets this as the maximum brightness difference. Fig. 6A is a diagram showing an example of a captured image F. In Fig. 6A, the symbol L1 indicates the line of interest. Fig. 6B is a histogram of the brightness of each pixel G on the line of interest L1 of the captured image F of Fig. 6A.

[0026] In the image shown in Fig. 6A, the pixel G with the greatest brightness has a brightness of 255pt, and the pixel G with the least brightness has a brightness of 3pt. If the captured image F acquired in step SA1 is the image shown in Fig. 6A, the control unit 13 derives 252pt (255pt-3pt) as the maximum brightness difference in the maximum brightness difference derivation process.

[0027] Here, it can be said that the greater the maximum luminance difference, the higher the probability that the situation is one in which the rear of the vehicle 2 is locally bright. In this case, there is a correlation between the magnitude of the maximum luminance difference and the degree to which the situation in which the rear of the vehicle 2 is locally bright (local degree) is satisfied, in that the local degree increases as the maximum luminance difference increases. Therefore, the maximum luminance difference can be used as an index value that represents the local degree in the range of 0 to 255 points. In consideration of the above, in step SB2, the control unit 13 derives the maximum luminance difference as the local degree.

[0028] As described above, in the local degree derivation process of step SA2, the control unit 13 derives the maximum luminance difference. Hereinafter, the maximum luminance difference derived in the local degree derivation process will be referred to as a "derived maximum luminance difference."

[0029] Returning to the flowchart FA of FIG. 3, after the local degree derivation process in step SA2 is performed, the control unit 13 executes a darkness degree derivation process (step SA3). The darkness degree derivation process is a process in which the control unit 13 derives a "darkness degree" that is the overall degree of darkness of the scenery recorded in the photographed image F based on the brightness situation of the photographed image F. In this embodiment, the control unit 13 derives the average value of the brightness of the pixels G that constitute the target line (hereinafter referred to as the "line average value") as the darkness degree. For example, when the photographed image F acquired in step SA1 is the photographed image F shown in FIG. 6A, the control unit 13 derives the line average value, which is the average value of the brightness of all the pixels G that constitute the target line L1 in FIG. 6A, as the darkness degree. Hereinafter, the line average value derived in the darkness degree derivation process is referred to as the "derived line average value".

[0030] Here, there is a correlation between the line average value and the degree (darkness) of "the overall darkness of the scenery recorded in the captured image F (= the darkness of the actual environment behind the vehicle 2)" such that the smaller the line average value, the greater the darkness. Therefore, the line average value can be used as an index value that expresses the darkness degree in the range of 0 to 255 points. In light of the above, in step SA3, the control unit 13 derives the line average value as the darkness degree based on the luminance state of the captured image F.

[0031] After executing the darkness degree derivation process in step SA3, the control unit 13 executes a mirror reflectance determination process (step SA4). The mirror reflectance determination process is a process for determining the mirror reflectance to be actually applied. Hereinafter, the "actually applied mirror reflectance" determined in step SA4 is referred to as the "applied mirror reflectance" and is distinguished from mirror reflectance in general. The mirror reflectance determination process will be described in detail below.

[0032] The flow chart FC in FIG. 7 is a flow chart showing the details of the mirror reflectance determination process. As shown in FIG. 7, in the mirror reflectance determination process, the control unit 13 first determines the level of the derived line average value (hereinafter referred to as the "darkness level") (step SC1). In this embodiment, the control unit 13 determines the darkness level as level LV1 when the derived line average value is 0 to 85 pt, as level LV2 when the derived line average value is 86 to 170 pt, and as level LV3 when the derived line average value is 171 pt to 255 pt. Level LV1 is the smallest level, indicating that the darkness outside the vehicle is the darkest. On the other hand, level LV3 is the largest level, indicating that the darkness outside the vehicle is the brightest. Note that the relationship between the range of the line average value and the darkness level exemplified in this embodiment is merely a simplified example. The relationship is an item that should be appropriately determined in advance based on tests or simulations from the viewpoint of realizing appropriate anti-glare.

[0033] Next, the control unit 13 determines the relationship definition information to be used based on the darkness level (step SC2). Here, in this embodiment, relationship definition information is prepared for each darkness level (level of darkness). Specifically, first relationship definition information corresponding to darkness level: level LV1, second relationship definition information corresponding to darkness level: level LV2, and third relationship definition information corresponding to darkness level: level LV3 are prepared. Then, when the darkness level is level LV1, the control unit 13 determines the first relationship definition information as the relationship definition information to be used, when the darkness level is level LV2, the second relationship definition information as the relationship definition information to be used, and when the darkness level is level LV3, the third relationship definition information as the relationship definition information to be used. Hereinafter, the relationship definition information determined here is referred to as "relationship definition information to be used."

[0034] The relationship definition information will be described below. The relationship definition information is information that defines the relationship between the maximum luminance difference and the mirror reflectance. The mirror reflectance corresponding to a certain value of the maximum luminance difference means the mirror reflectance that realizes appropriate anti-glare when the maximum luminance difference is the certain value. In the relationship definition information, the mirror reflectance is associated with each possible value of the maximum luminance difference. Therefore, any maximum luminance difference can be converted into a mirror reflectance by using the relationship definition information.

[0035] In FIG. 8, the first to third relationship definition information are shown by curves on a coordinate system with the mirror reflectance on the horizontal axis and the maximum luminance difference on the vertical axis. The curve CV1 in FIG. 8 shows the first relationship definition information, the curve CV2 shows the second relationship definition information, and the curve CV3 shows the third relationship definition information. Focusing on the curve CV1 in FIG. 8, in the first relationship definition information, the maximum luminance difference: 200pt and the mirror reflectance: 40% correspond to each other. This means that when the first relationship definition information is used to determine the mirror reflectance, the maximum luminance difference: 200pt is converted to the mirror reflectance: 40%. Furthermore, as shown by the curve CV1, in the first relationship definition information, the larger the maximum luminance difference, the smaller the mirror reflectance. This relationship also holds for the second and third relationship definition information.

[0036] 8, when the maximum luminance difference is the same, the mirror reflectance of the first relationship definition information is smaller than the mirror reflectance of the second relationship definition information and smaller than the mirror reflectance of the third relationship definition information. For example, when the maximum luminance difference is 200pt, the mirror reflectance of the first relationship definition information is 40%, the mirror reflectance of the second relationship definition information is 70%, and the mirror reflectance of the third relationship definition information is 80%, so that the mirror reflectance of the first relationship definition information (40%) is smaller than the mirror reflectance of the second relationship definition information (70%) and smaller than the mirror reflectance of the third relationship definition information (80%). In this embodiment, when the maximum luminance difference is 125pt or less for any of the first to third relationship definition information, the reflectance is 100%.

[0037] After the process of step SC2, the control unit 13 determines the applicable mirror reflectance based on the usage relationship definition information (step SC3). Specifically, the control unit 13 converts the derived maximum luminance difference into a mirror reflectance using the usage relationship definition information, and determines this as the applicable mirror reflectance. For example, referring to FIG. 8, when the usage relationship definition information is the first relationship definition information and the maximum luminance difference is 200pt, the control unit 13 determines the applicable mirror reflectance to be 40%. Also, for example, when the usage relationship definition information is the third relationship definition information and the maximum luminance difference is 200pt, the control unit 13 determines the applicable mirror reflectance to be 80%. The above is the content of the mirror reflectance determination process.

[0038] As described above, when one type of relationship definition information is focused on, the relationship is established in the relationship definition information such that the larger the maximum luminance difference, the smaller the mirror reflectance. In other words, if the darkness level is the same, the control unit 13 determines the mirror reflectance so that the reflectance is smaller as the maximum luminance difference (local degree) is larger. This is for the following reason. In other words, the larger the maximum luminance difference, the higher the probability that the situation is one in which the rear of the vehicle 2 is locally bright (for example, a situation in which the light of the headlights of a following vehicle is projected toward the vehicle 2 when it is dark outside the vehicle). Therefore, in order to achieve appropriate anti-glare, it is basically required to lower the mirror reflectance as the maximum luminance difference is larger. For the above reasons, the control unit 13 determines the mirror reflectance so that the reflectance is smaller as the maximum luminance difference (local degree) is larger.

[0039] As described above, the control unit 13 determines the first relationship definition information as the usage relationship definition information when the darkness level is level LV1, determines the second relationship definition information as the usage relationship definition information when the darkness level is level LV2, and determines the third relationship definition information as the usage relationship definition information when the darkness level is level LV3. When the maximum luminance difference is the same, "mirror reflectance of the first relationship definition information < mirror reflectance of the second relationship definition information < mirror reflectance of the third relationship definition information". In other words, the control unit 13 determines the mirror reflectance so that the reflectance becomes smaller as the (level of) the derived line average value becomes smaller (= the (level of) the degree of darkness becomes larger) even if the maximum luminance difference is the same. This is for the following reason.

[0040] That is, the smaller the derived line average value, the darker the actual environment behind the vehicle 2 (hereinafter referred to as the "external environment") is. If the conditions of the light irradiated from behind the vehicle 2 toward the vehicle 2 are the same, the darker the external environment is, the greater the degree to which the light reflected by the mirror 1 when the reflectance is 100% will cause the driver to feel glare. Therefore, in order to accurately suppress the glare felt by the driver, it is necessary to reduce the reflectance as the derived line average value is smaller (= the greater the degree of darkness) even if the maximum luminance difference is the same. For the above reasons, the control unit 13 determines the mirror reflectance so that the reflectance is smaller as the derived line average value is smaller (= the greater the degree of darkness) even if the maximum luminance difference is the same.

[0041] As described above, the control unit 10 determines the applicable mirror reflectance based on the brightness of the captured image F in the mirror reflectance determination process of step SA4.

[0042] After the process of step SA4, the control unit 13 controls the optical device 15 of the mirror 1 so that the mirror reflectance of the optical device 15 becomes the applicable mirror reflectance determined in step SA4 (step SA5).

[0043] Since the above process is performed in a cycle according to the frame rate, the mirror reflectance of the mirror 1 is automatically and dynamically adjusted to an appropriate value determined based on the brightness of the captured image F in that cycle.

[0044] As described above, the control device 10 includes a control unit 13 that acquires a captured image F based on the image capturing results of the camera 11 capturing an image of the rear of the vehicle 2, and determines the mirror reflectance, which is the reflectance of the mirror 1, based on the brightness of the captured image F. According to this configuration, the mirror reflectance is determined based on the brightness of the image F captured by the camera 11 capturing an image of the rear of the vehicle 2, rather than on a light amount sensor provided on the mirror, so that it is possible to automatically control the anti-glare without providing a light amount sensor on the mirror 1, and moreover, it is possible to achieve appropriate anti-glare.

[0045] <Modification of local degree derivation process> Next, a modified example of the local degree derivation process (step SA2 of the flow chart FA, flow chart FB) of the above embodiment will be described. In the above embodiment, a specific example of the method in which the control unit 13 determines the line of interest has been described through the explanation of the line of interest determination process (step SB1) included in the local degree derivation process. However, the method in which the control unit 13 determines the line of interest is not limited to the method exemplified in the above embodiment. For example, the line of interest may be a line of pixels G extending in the y-axis direction, such as line L2 in FIG. 9. It may also be a line of pixels G extending obliquely to the x-axis, such as line L3 or line L4 in FIG. 9. It may also be determined in advance which line is to be the line of interest. In this case, which line is to be the line of interest is appropriately determined based on the results of a prior test or simulation, from the viewpoint of ensuring the appropriateness of the local degree (maximum luminance difference in the above embodiment) and the darkness degree (line average value in the above embodiment) derived using the line of interest.

[0046] Further, the control unit 13 may be configured to execute the process of the flowchart FD of FIG. 10 in place of the process of the flowchart FB of FIG. 4 with respect to the derivation of the local degree. Hereinafter, the modified example in which the process of the flowchart FD is executed will be referred to as the "first modified example". In detail, the control unit 13 first executes a target line group determination process (step SD1). The target line group determination process is a process for determining a target line group. The target line group is a line group consisting of a plurality of x-axis lines (five in the first modified example) extending in the x-axis direction on the photographed image F. In step SD1, the control unit 13 determines the target line group by the following method. That is, the control unit 13 determines the target line by the same method as that described in the target line determination process (step SB1) of the above embodiment. Next, the control unit 13 determines a group of five x-axis lines including the target line and two x-axis lines in the y-axis + direction and two x-axis lines in the y-axis - direction with the target line as the target line group.

[0047] FIG. 11 is a diagram showing the photographed image F in a manner suitable for explanation. For example, when the line of interest is the line of interest LH1, the control unit 13 determines a group of five x-axis lines belonging to a range A1 as the line of interest group. With reference to FIG. 11, when the line of interest is the x-axis line Lx1 located at the end of the photographed image F in the negative y-axis direction or the x-axis line Lx2 located in the positive y-axis direction from the x-axis line Lx1, the control unit 13 determines five x-axis lines from the x-axis line Lx1 toward the positive y-axis direction (a group of five x-axis lines belonging to a range A2 in FIG. 11) as the line of interest group. Similarly, when the line of interest is the x-axis line Lx3 located at the end of the photographed image F in the positive y-axis direction or the x-axis line Lx4 located in the negative y-axis direction from the x-axis line Lx3, the control unit 13 determines five x-axis lines from the x-axis line Lx3 toward the negative y-axis direction (a group of five x-axis lines belonging to a range A3 in FIG. 11) as the line of interest group.

[0048] After the processing of step SD1, the control unit 13 executes a maximum average luminance difference derivation process (step SD2). The processing of step SD2 will be described in detail below. FIG. 12 is a diagram used to explain the processing of step SD2. As shown in FIG. 12, the control unit 13 divides the target line group into blocks B that are arranged side by side with no gaps in the x-axis direction. Each block B is composed of five pixels G in the x-axis direction and five in the y-axis direction, for a total of 25 pixels G. Note that if the number of pixels G in the x-axis direction of the target line group is not a multiple of five, the configuration of one of the blocks B is modified.

[0049] Next, the control unit 13 derives the average value of the luminance of each pixel G in the block B. Next, the control unit 13 derives the "maximum average luminance difference" which is the difference between the average values ​​of the block B with the largest average value and the block B with the smallest average value as the local degree. Here, there is a correlation between the magnitude of the maximum average luminance difference and the degree of satisfaction of the situation that the rear of the vehicle 2 is locally bright (local degree) such that the larger the maximum average luminance difference, the larger the local degree. Therefore, the maximum average luminance difference can be used as an index value expressing the local degree in the range of 0 to 255 pt, similar to the maximum luminance difference in the above embodiment. Regarding the first modified example, the control unit 13 executes various processes using the maximum average luminance difference instead of the maximum luminance difference as the local degree. Also, the relationship definition information is information defining the relationship between the maximum average luminance difference and the mirror reflectance.

[0050] Although the first modified example has been described above, the following modified example can be further adopted for the first modified example. That is, the method of determining the line group of interest is not limited to the exemplified method. For example, the line group of interest may be a group of lines of pixels G extending in the y-axis direction, such as the line group LG1 in FIG. 13. It may also be a group of lines of pixels G extending diagonally to the x-axis, such as the line group LG2 or line group LG3 in FIG. 13. It may also be determined in advance which line group is to be the line group of interest. The number of pixels G included in the block B does not need to be "5 in the x-axis direction and 5 in the y-axis direction, totaling 25" (hereinafter, the same case will be expressed as 5×5=25), and may be, for example, 9 pixels of 3×3 or 12 pixels of 4×6. The blocks B do not need to be arranged side by side without gaps on the line group of interest, and may be arranged side by side with gaps between them, for example, as shown in FIG. 14(A). There may also be an overlapping portion between adjacent blocks B, for example, as shown in FIG. 14(B).

[0051] In addition, the content of the local degree is not limited to the above-mentioned example. In other words, the local degree may be a degree that can be derived based on the brightness state of the captured image F and satisfies the state that the rear of the vehicle 2 is locally bright. In addition, the control unit 13 may be configured to use a model trained by a predetermined machine learning method when deriving the local degree.

[0052] <Modification of Darkness Degree Deriving Process> Next, a modified example of the darkness degree derivation process (step SA3) of the above embodiment will be described. In the above embodiment, the control unit 13 derived the line average value of the target line as the darkness degree. As described above, the target line can be determined by various methods. However, the darkness degree is not limited to the line average value of the target line. For example, the control unit 13 may determine a group of target lines and then derive the average value of the luminance of the pixels constituting the group of target lines as the darkness degree. This configuration is particularly effective when the control unit 13 derives the local degree by the method described in the first modified example. For example, the control unit 13 may derive the average value of the luminance of all pixels G constituting the photographed image F as the darkness degree. For example, the control unit 13 may specify a partial area of ​​the photographed image F by image processing and derive the average value of the luminance of the pixels G belonging to the partial area as the darkness degree.

[0053] <Modification of mirror reflectance determination process> Next, a modified example of the mirror reflectance determination process of the above embodiment will be described. In the above embodiment, the control unit 13 determines the mirror reflectance (applied mirror reflectance) using three types of relationship definition information prepared in advance. However, the method in which the control unit 13 determines the mirror reflectance is not limited to the method exemplified in the above embodiment. For example, the control unit 13 may be configured to determine the mirror reflectance (applied mirror reflectance) using a "calculation formula that inputs the darkness degree and the local degree as parameters and outputs the mirror reflectance." This calculation formula derives the mirror reflectance by a calculation method in which, if the darkness degree is the same, the greater the local degree, the smaller the reflectance, and, even if the local degree is the same, the greater the darkness degree, the smaller the reflectance.

[0054] In the first to third relationship definition information, the relationship between the maximum luminance difference and the mirror reflectance is proportional. However, the relationship between the maximum luminance difference and the mirror reflectance is not limited to a proportional relationship. The relationship between the maximum luminance difference and the mirror reflectance is an item that should be determined appropriately from the viewpoint of realizing appropriate anti-glare. For example, the curves CV1 to C3 in FIG. 8 may not be straight lines, but may be curved or bent.

[0055] The control unit 13 may be configured not to use the darkness degree when determining the applicable mirror reflectance. In this configuration, the control unit 13 does not execute the darkness degree derivation process. In this configuration, the control unit 13 executes, for example, the following process. For example, one type of relationship definition information is prepared as the relationship definition information. The control unit 13 then determines the local degree (maximum luminance difference in the above embodiment) as the applicable mirror reflectance without deriving the darkness degree, using the one type of relationship definition information prepared. Also, for example, the control unit 13 determines the mirror reflectance (applied mirror reflectance) using a "calculation formula that inputs the local degree as a parameter and outputs the mirror reflectance". This calculation formula derives the mirror reflectance using a calculation method in which the reflectance decreases as the local degree increases.

[0056] In addition, the method in which the control unit 13 determines the mirror reflectance based on the luminance state of the captured image F is not limited to the above-mentioned method. In other words, the mirror reflectance may be derived by the control unit 13 using a method that reflects the luminance state of the captured image F. In addition, the control unit 13 may be configured to use a model trained by a predetermined machine learning method when deriving the mirror reflectance.

[0057] Although one embodiment of the present invention (including modifications, the same applies below) has been described above, the above embodiment is merely one example of a specific embodiment of the present invention, and the technical scope of the present invention should not be interpreted as being limited thereby. In other words, the present invention can be embodied in various forms without departing from the gist or main characteristics thereof.

[0058] For example, in the above-described embodiment, the mirror 1 is not provided with a function for displaying an image, but the mirror 1 may be configured to have this function.

[0059] In addition, for example, in the above-described embodiment, the mirror reflectance of the mirror 1 is changed by the optical device 15. In this regard, an electrochromic layer may be provided instead of the optical device 15, and the mirror reflectance may be changed by the electrochromic layer.

[0060] In addition, for example, in the above embodiment, the mirror 1 is not provided with a light amount sensor, but it may be provided with one. In other words, it is naturally permissible to provide one or more light amount sensors on the mirror 1 to realize a function other than the automatic anti-glare function.

[0061] Furthermore, the functional blocks shown in the above embodiments can be realized by any hardware or by cooperation between any hardware and any software. In other words, these functional blocks are not limited to specific hardware. For example, when a certain functional block is configured by hardware and software, it can have the following configuration. That is, this functional block is configured to include a CPU, RAM, and ROM of a computer. And, this functional block executes processing by the CPU reading a program stored in the ROM or other recording medium into the RAM and executing it.

[0062] In addition, for example, the control unit 13 may cooperate with an external device to execute various processes described above as being executed solely by the control unit 13. As an example, the control unit 13 may execute processes in cooperation with an external device (e.g., a cloud server) that can communicate with the control unit 13 via a network.

[0063] The processing units in the flowcharts of the above embodiments are divided according to the main processing contents in order to make the processing easier to understand. The method of dividing the processing units and their names do not limit the present invention. The processing of each device can be divided into more processing units according to the processing contents. Also, one processing unit can be divided to include more processing. Also, as long as similar processing can be performed, the processing order of the above flowcharts is not limited to the example shown in the figure.

[0064] For example, the embodiment may include the provision of a program executed by the computer of the control device 10. The embodiment may also include the provision of a recording medium on which the program is recorded so as to be readable by a computer. The recording medium may be a magnetic or optical recording medium or a semiconductor memory device. Specific examples of the recording medium include portable or fixed recording media such as flexible disks, HDDs (Hard Disk Drives), CD-ROMs (Compact Disk Read Only Memory), DVDs (Digital Versatile Disks), Blu-ray (registered trademark) Disks, magneto-optical disks, flash memories, and card-type recording media. [Explanation of symbols]

[0065] 1. Mirror 2 Vehicles 10 Control device 11 Camera 12 Control System 13 Control section

Claims

1. A control device that is provided in a vehicle cabin and executes processing related to a mirror configured to be able to change a reflectance, A control unit is provided for acquiring a captured image based on the result of shooting by a camera that captures an image of the rear of the vehicle, and determining a mirror reflectance, which is the reflectance of the mirror, based on the brightness of the captured image. A control device comprising:

2. The control unit is Deriving a local degree, which is a degree to which a condition in which a rear of the vehicle is locally bright is satisfied, based on a luminance condition of the captured image; The mirror reflectance is determined so that the reflectance decreases as the local degree increases. The control device according to claim 1 .

3. The control unit is A difference in luminance between a pixel having the highest luminance and a pixel having the lowest luminance among pixels on a line of interest, which is a line extending in a predetermined direction on the photographed image, is derived as the local degree.

3. The control device according to claim 2.

4. The control unit is Deriving an average value of luminance of pixels in a plurality of blocks arranged in a predetermined direction on a line group of interest that is composed of a plurality of lines extending in a predetermined direction in the photographed image; The difference between the average values ​​of the block with the largest average value and the block with the smallest average value is derived as the local degree.

3. The control device according to claim 2.

5. The control unit is Deriving a darkness degree, which is a degree of overall darkness of a scene recorded in the photographed image, based on a luminance state of the photographed image; The mirror reflectance is determined so that the greater the degree of darkness, the smaller the reflectance becomes even if the local degree is the same.

3. The control device according to claim 2.

6. relationship definition information is prepared for each level of the darkness degree, the relationship between the local degree and the mirror reflectance being defined; The control unit is A level of the darkness degree is derived, and the mirror reflectance is determined using the relationship definition information corresponding to the derived level.

6. The control device according to claim 5.

7. The control unit is The degree of darkness and the degree of locality are input as parameters, and a calculation formula for outputting the mirror reflectance is used to determine the mirror reflectance.

6. The control device according to claim 5.

8. The control unit is The average value of the luminance of pixels constituting a line of interest, which is a line extending in a predetermined direction on the photographed image, is derived as the degree of darkness.

8. The control device according to claim 5, wherein the control device is a control device for controlling a control unit.

9. The control unit is The average value of the luminance of pixels constituting a group of lines of interest, which is made up of a plurality of lines extending in a predetermined direction in the photographed image, is derived as the degree of darkness.

8. The control device according to claim 5, wherein the control device is a control device for controlling a control unit.

10. A control system including a mirror provided in a vehicle cabin and configured to change a reflectance, and a control device that executes processing related to the mirror, The control device acquires a captured image based on a result of shooting by a camera that captures an image of the rear of the vehicle, and determines a mirror reflectance, which is the reflectance of the mirror, based on a luminance state of the captured image. A control system comprising:

11. A control method for a control device that executes a process related to a mirror that is provided in a vehicle cabin and is configured to be able to change the reflectance, comprising: A control unit of the control device acquires a captured image based on a captured image of a camera that captures an image of a rear area of ​​the vehicle; and a step of determining a mirror reflectance, which is a reflectance of the mirror, based on a luminance condition of the captured image by the control unit of the control device. A control method comprising:

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