JP2015058747A - Vehicle lamp body control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle lamp body control device which can control a lamp body more appropriately.SOLUTION: A lamp body control device 1 comprises: a lamp body controller 81 for controlling lighting or extinction of a lamp body 12 which outputs illumination light outward from a vehicle C in accordance with illuminance I around the vehicle C; a contrast detection part 82 for detecting contrast CR of a captured image Img around the vehicle C which a camera 11 mounted on the vehicle C has captured; and a threshold changing part 83 for changing at least one of a first threshold I_th1 which is a threshold of the illuminance I when the lamp body controller 81 switches the lamp body 12 from an extinction state to a lighting state, or a second threshold I_th2 which is a threshold of the illuminance I when the lamp body controller 81 switches the lamp body 12 from a lighting state to the extinction state, in accordance with the contrast CR detected by the contrast detection part 82.

Description

  The present invention relates to a vehicle lamp control device that controls a lamp (such as a headlamp) that outputs illumination light to the outside of a vehicle.

  Conventionally, a vehicle lamp control device that controls a lamp that outputs illumination light to the outside of the vehicle is known (see, for example, Patent Document 1 or Patent Document 2). This vehicle lamp control device lights the lamp when the illuminance around the vehicle is below a predetermined value.

  Another vehicle lamp control device is known (for example, see Patent Document 3). This vehicle lamp control device calculates the average brightness of the road surface area corresponding to the road portion ahead of the vehicle, the vanishing point area including the vanishing point, and the sky area corresponding to the sky part based on the captured image of the in-vehicle camera. To do. And the said vehicle lamp control apparatus is lighting the lamp which outputs illumination light outside the vehicle, when it determines with all the areas | regions being dark.

Japanese Patent Laid-Open No. 1-309836 Japanese Utility Model Publication No. 5-46571 JP 2009-280047 A

  By the way, even when the periphery of the vehicle is relatively bright, there is a situation where the driver feels that the illumination light is to be output outward by the lamp body, or a situation where it is desirable to output the light. Such a situation is, for example, a cloudy or stormy weather situation or a situation where fog is generated. In such a situation, the periphery of the vehicle is relatively bright, and the brightness tends to be uniform overall. For this reason, in the vehicle lamp control device described in Patent Documents 1 to 3, the lamp may not be automatically turned on in the above situation.

  This invention is made | formed in view of the above point, and it aims at providing the vehicle lamp control apparatus which can control a lamp more appropriately.

  In the present invention, a lamp control unit that controls lighting or extinguishing of a lamp that outputs illumination light to the outside of the vehicle according to the brightness of the surroundings of the vehicle, and a camera mounted on the vehicle imaged A contrast detection unit that detects a contrast of an image around the vehicle, a first threshold that is a threshold value of the brightness at which the lamp control unit changes the lamp from a light-off state to a light-on state, and the lamp control A threshold value changing unit that changes at least one of the second threshold values, which is a threshold value of the brightness that changes the lamp from a lighting state to a non-lighting state, according to the contrast detected by the contrast detection unit. It is characterized by.

  In the present invention, the threshold value changing unit changes at least one of the first threshold value and the second threshold value according to the contrast detected by the contrast detection unit from the image captured by the camera. When the first threshold value is changed, the lamp body can be turned on at a timing suitable for the detected contrast state. When the second threshold value is changed, the lamp body can be turned off at a timing suitable for the detected contrast state. Thus, according to the present invention, the lamp can be controlled more appropriately.

  In the present invention, the threshold value changing unit determines the level of the contrast detected by the contrast detection unit, and when the detected contrast is relatively low, compared to a case where the detected contrast is relatively high. It is preferable that at least one of the first threshold and the second threshold is changed so that at least one of the first threshold and the second threshold is increased.

  According to this configuration, in the state where the contrast is low as described above, the threshold value changing unit has at least one of the first threshold value and the second threshold value so that at least one of the first threshold value and the second threshold value becomes higher. Change either one.

  When the first threshold value is changed so that the first threshold value is increased, the lamp changes from the unlit state to the lit state when the contrast is low even when the periphery of the vehicle is relatively bright. It becomes easy.

  In addition, when the second threshold value is changed so that the second threshold value is increased, the lamp is easily maintained in the lighting state when the contrast is low even when the periphery of the vehicle is relatively bright. Become.

  As described above, with the above configuration, even when the periphery of the vehicle is bright, the contrast is low, such as a situation where the driver feels that it is desired to output the illumination light to the outside by the lamp or a situation where it is desirable to output the illumination light. In the state, the lamp can be turned on automatically or the lighting state can be maintained.

  In this invention, the said 2nd threshold value is set to the value higher than the said 1st threshold value, The said lighting body control part is the said 1st threshold value from the brightness whose said brightness is higher than the said 1st threshold value. When the following brightness is reached, the lamp is changed from the unlit state to the lit state, and the brightness is higher than the second threshold value from the lower brightness than the second threshold value. In some cases, the lamp is preferably configured to change from a lighting state to a lighting state.

  According to this configuration, when the lamp is turned off after being turned off, the brightness of the surroundings of the vehicle is changed from the brightness equal to or lower than the first threshold to the second threshold (lower than the first threshold). It is when it increases more than (high value). Further, when the lamp is turned on after being turned off, the brightness of the surroundings of the vehicle is less than the first threshold (a value lower than the second threshold) from the brightness of the second threshold or higher. When it decreases. As described above, since the brightness needs to change more than the difference between the first threshold value and the second threshold value in order for the lamp to switch from one of the unlit state and the lit state to the other, the lighting of the lamp is turned on and off. Can be suppressed from being repeated frequently.

  In addition, when the first threshold value and the second threshold value are set as described above, the threshold value changing unit determines the level of contrast detected by the contrast detection unit, and the detected contrast Is relatively high, at least of the first threshold and the second threshold so that the difference between the first threshold and the second threshold is larger than when the detected contrast is relatively low. It is preferable to be configured to change any of them.

  For example, a shadow due to a building or the like is likely to occur during fine weather. For this reason, when the vehicle travels in fine weather, the brightness of the surroundings of the vehicle tends to change greatly frequently due to the influence of the shadow. Further, in clear weather, the difference in brightness between a shadow of a building or the like and a portion that is not the shadow is large, so that the contrast of an image captured by the camera tends to be high.

  According to the above configuration, when the difference between the first threshold value and the second threshold value is increased, the lamp body is turned off after being turned off, and the lamp body is turned off from the turned on state. When the lighting state is turned on after that, the brightness needs to change more greatly. Therefore, when the vehicle travels in fine weather, lighting and extinguishing of the lamp are frequently repeated even when the brightness of the surroundings of the vehicle frequently changes greatly due to the influence of a shadow of a building or the like. Can be suppressed.

  In the present invention, an illuminance sensor that generates an output according to the brightness is provided, and the lamp control unit adopts an aspect configured to detect the brightness based on the output of the illuminance sensor. it can. According to this configuration, the lamp control unit can control the lamp according to the brightness detected based on the output of the illuminance sensor.

  In the present invention, the lamp control unit may be configured to detect the brightness based on luminance of an image captured by the camera. According to this configuration, the lamp control unit can control the lamp according to the brightness detected based on the luminance obtained using the image captured by the camera.

The block diagram of the vehicle lamp control apparatus of embodiment of this invention. Explanatory drawing of the attachment aspect to the vehicle of the vehicle lamp control apparatus shown in FIG. The flowchart which showed the process sequence of the lamp control process in the vehicle lamp control apparatus shown in FIG. The flowchart which showed the process sequence of the threshold value change process in the vehicle lamp control apparatus shown in FIG. (A) is a diagram showing the ambient illuminance I, the first threshold I_th1, and the second threshold I_th2, and (b) is a diagram comparing the first threshold I_th1 and the second threshold I_th2 when the contrast is high and low. (A) is a figure which shows a captured image, (b) is a figure shown about each area | region. (A) is a figure shown about the captured image at the time of fine weather, (b) is a figure shown about the captured image at the time of cloudy weather, (c) is a figure shown about the captured image at the time of stormy weather. Explanatory drawing of the method of determining whether the contrast in another form is falling.

  Hereinafter, a vehicle lamp control device 1 (hereinafter simply referred to as “lamp control device”) according to an embodiment of the present invention will be described. 1 and 2, the lamp control device 1 includes an illuminance sensor 2 and a control device 8. The vehicle C on which the lamp control device 1 is mounted includes a camera 11 and a lamp 12.

  The camera 11 is a visible light camera, and outputs a captured image Img obtained by imaging the front of the vehicle C (for example, see FIG. 6A) as a signal. The camera 11 is disposed in the vicinity of the rear-view mirror (not shown) of the vehicle C (see FIG. 2).

  The lamp body 12 is a light that outputs illumination light to the outside of the vehicle C. In the present embodiment, the lamp is a headlamp. For example, the lamp is composed of at least one of a headlamp, a vehicle width lamp, a front fog lamp, a rear fog lamp, a tail lamp, and the like. Also good.

  The illuminance sensor 2 detects the illuminance I around the vehicle C (corresponding to “brightness” of the present invention, hereinafter referred to as “ambient illuminance”). The illuminance sensor 2 outputs a signal representing the detected ambient illuminance I to the outside. Further, the illuminance sensor 2 is provided in the vicinity of a rear-view mirror (not shown) of the vehicle C. The illuminance sensor 2 may be provided on the upper part of the instrument panel.

  The control device 8 is constituted by an electronic control unit having a CPU, a memory, etc. (not shown). Signals output from the illuminance sensor 2 and the camera 11 are input to the control device 8. In addition, the control device 8 has functions as a lamp control unit 81, a contrast detection unit 82, and a threshold change unit 83.

  Next, control processing executed by the control device 8 will be described. The control process executed by the control device 8 includes a lamp control process (see FIG. 3) and a threshold value changing process (see FIG. 4).

  The lamp control process is a control process for controlling lighting and extinguishing of the lamp 12. Here, the lamp control process corresponds to a control process executed by the lamp control unit 81. In the lamp control process, the first threshold value I_th1 and the second threshold value I_th2 are used as the threshold values of the ambient illuminance I (see FIG. 5A). The second threshold I_th2 is set higher than the first threshold I_th1.

  The first threshold value I_th1 is a threshold value of the ambient illuminance I that changes the lamp body 12 from the unlit state to the lit state. When the peripheral illuminance I changes from the illuminance higher than the first threshold I_th1 to the illuminance equal to or lower than the first threshold I_th1, the control device 8 changes the lamp body 12 from the unlit state to the lit state. The second threshold value I_th2 is a threshold value of the ambient illuminance I that changes the lamp body 12 from the lit state to the unlit state. When the ambient illuminance I changes from the illuminance lower than the second threshold I_th2 to the illuminance equal to or higher than the second threshold I_th2, the control device 8 changes the lamp body 12 from the lighting state to the extinguished state.

  Thereby, when the lamp 12 is turned off after being turned off, the ambient illuminance I is increased from the illuminance below the first threshold I_th1 to the illuminance above the second threshold I_th2. In addition, when the lamp 12 is turned on after being turned off, the ambient illuminance I is reduced from the illuminance greater than or equal to the second threshold I_th2 to the illuminance less than or equal to the first threshold I_th1. Thus, in order for the lamp body 12 to switch from one of the unlit state and the lit state to the other, the ambient illuminance I needs to change more than the difference between the first threshold value I_th1 and the second threshold value I_th2. It is possible to suppress the repeated lighting and extinguishing of 12 frequently.

  In the threshold value changing process, the control device 8 first detects the contrast CR of the captured image Img around the vehicle C captured by the camera 11 (the control process in which the detection process is executed by the contrast detection unit 82). Equivalent to Then, the control device 8 changes the first threshold value I_th1 and the second threshold value I_th2 in accordance with the detected contrast CR (the changing process corresponds to a control process executed by the threshold changing unit 83). .

  Next, details of the lamp control process executed by the control device 8 will be described with reference to FIGS. 3 and 5A.

  Here, FIG. 5A is a diagram showing a change in the ambient illuminance I over time. In FIG. 5A, the horizontal axis is time, and the vertical axis is ambient illuminance I.

  The control device 8 executes the lamp control process according to the flowchart shown in FIG. 3 every predetermined control cycle.

  The control device 8 first determines whether or not the lamp body 12 is turned off in the first step ST1. When it is determined in step ST1 that the lamp body 12 is in the extinguished state (for example, before time t11 or after time t12 in FIG. 5A), the control device 8 proceeds to step ST2.

  In step ST2, the control device 8 has changed from a state in which the ambient illuminance I is greater than the first threshold I_th1 to a state that is less than or equal to the first threshold I_th1 (hereinafter referred to as a “first change”). Or not). If the control device 8 determines in step ST2 that the ambient illuminance I has changed first (for example, at the time t11 in FIG. 5A), the control device 8 proceeds to step ST3 and turns on the lamp body 12. When the process of step ST3 ends or when it is determined in step ST2 that the ambient illuminance I has not changed first, the control device 8 ends this flowchart.

  When the control device 8 determines in step ST1 that the lamp body 12 is not turned off (that is, in the lighting state) (for example, in the case of time t11 to t12 in FIG. 5A), the control device 8 performs step ST4. Proceed to

  In step ST4, the control device 8 changes from the state in which the ambient illuminance I is smaller than the second threshold I_th2 to a state equal to or greater than the second threshold I_th2 (hereinafter, the change in the ambient illuminance I is referred to as “second change”. Or not). If the control device 8 determines in step ST4 that the ambient illuminance I has changed second (for example, at time t12 in FIG. 5A), the control device 8 proceeds to step ST5 and turns off the lamp body 12. When the process of step ST5 ends or when it is determined in step ST4 that the ambient illuminance I has not changed second, the control device 8 ends this flowchart.

  Next, the details of the threshold value changing process executed by the control device 8 will be described with reference to FIG. The control device 8 executes the threshold value changing process according to the flowchart shown in FIG. 4 every predetermined control cycle.

  First, in step ST101, the control device 8 smoothes the captured image Img captured by the camera 11 (see, for example, FIG. 6A). Thereby, the amount of calculation of the image processing in the threshold value changing process after step ST101 is reduced. For the smoothing, various known methods such as an averaging filter for obtaining an average value of pixel values in a predetermined area can be used. Note that step ST101 may be omitted as the threshold value changing process.

  The control device 8 then proceeds to step ST102 and removes the disturbance component from the image obtained in step ST101. Here, the disturbance component is, for example, a reflection component. The control device 8 then proceeds to step ST103, and performs clustering of the image according to the luminance histogram of the image obtained in step ST102. Each of the plurality of clusters (partial regions in the image) obtained as a result is an aggregate of pixels having similar brightness.

  The control device 8 then proceeds to step ST104, and extracts the sky region A1 and the road surface region A2 based on the cluster obtained by clustering in step ST103 (see FIG. 6B). Here, the sky region A1 is a region representing the sky, and the road surface region A2 is a region representing the road surface (the surface of the road).

  Specifically, for example, in each cluster, the control device 8 extracts the sky region A1 and the road surface region A2 based on the position and size. In addition, although detailed illustration is abbreviate | omitted in FIG.6 (b), the image part of the white line in road surface area A2 is excluded from the said road surface area A2.

  Subsequently, the control device 8 proceeds to step ST105, and calculates image information in each of the sky region A1, the road surface region A2, and the front region A3.

  Here, the front area A3 is an area in which the position and size in the captured image are defined in advance. The front area A3 is defined so as to exclude an area where the luminance tends to be high (for example, the sky).

  In the present embodiment, the position and size of the front area A3 are defined in advance (that is, fixed), but the front area A3 may be variably set.

  The image information is information for determining the level of the contrast CR of the captured image Img (that is, calculating the image information corresponds to detecting the contrast CR). In the present embodiment, the image information includes, for example, luminance dispersion, color dispersion, and average luminance in the image. As described above, since various pieces of information are included in the image information, the level of the contrast CR can be determined with higher accuracy. The image information is not limited to the information of the present embodiment, and may be, for example, at least one of luminance dispersion, color dispersion, and luminance average, or information other than these may be included. Good.

  In addition, when calculating the image information in the road surface area A2 and the front area A3, the control device 8 calculates the image information after removing a high luminance area (for example, an image portion of a white line). Thus, for example, when the environment around the vehicle C (weather conditions, etc.) is the same, when driving on a road where there are no white lines or few white lines, and on roads where many white lines exist This prevents a large difference in the calculated image information.

  Subsequently, the control device 8 proceeds to step ST106, and determines whether or not the contrast CR of the captured image Img is low based on the image information of each region A1, A2, A3 and the evaluation data.

  Here, the evaluation data includes the image information of each area A1, A2, A3 and the state of view (the state of view is poor (for example, cloudy or stormy state) or other state (for example, clear sky)) Data). The evaluation data is calculated by learning using multivariate analysis based on the image information of each of the areas A1, A2, and A3 in each of the plurality of captured images Img captured in various visual field states. The

  The control device 8 has a low contrast CR of the captured image Img when the visual field state is identified as “a poor visual field state” based on the image information and the evaluation data of the areas A1, A2, and A3. And when it is determined that the state of view is not “a state of poor view”, it is determined that the contrast CR of the captured image Img is high.

  For example, the control device 8 has small values of “the luminance dispersion of the front area A3”, “the luminance distribution of the sky area A1”, and “the color dispersion of the sky area A1”, and “the average luminance of the sky area A1”. And the average difference in luminance of the road surface area A2 (that is, the difference in contrast between the sky area A1 and the road surface area A2) is small, it is determined that the visibility is poor.

  If the control device 8 determines in step ST106 that the contrast CR of the captured image Img is low, the control device 8 proceeds to step ST107. In step ST107, the control device 8 sets the first threshold I_th1 to the first threshold I_th1_L for low contrast and the second threshold I_th2 to the second threshold I_th2_L for low contrast (see FIG. 5B). When the process of step ST107 ends, the control device 8 ends this flowchart.

  If the control device 8 determines in step ST106 that the contrast CR of the captured image Img is high, the control device 8 proceeds to step ST108. In step ST108, the control device 8 sets the first threshold I_th1 to the first threshold I_th1_H for high contrast and the second threshold I_th2 to the second threshold I_th2_H for high contrast, respectively (see FIG. 5B). When the process of step ST108 ends, the control device 8 ends this flowchart.

  Here, the first threshold I_th1_L for the low contrast (when the contrast CR is relatively low) is set higher than the first threshold I_th1_H for the high contrast (when the contrast CR is relatively high). Has been. The second threshold value I_th2_L for the low contrast (when the contrast CR is relatively low) is set higher than the second threshold value I_th2_H for the high contrast (when the contrast CR is relatively high). ing.

  Furthermore, the difference between the two high contrast threshold values I_th1_H and I_th2_H (hereinafter referred to as “high contrast threshold difference”) ΔI_th_H is the difference between the two low contrast threshold values I_th1_L and I_th2_L (hereinafter referred to as “low contrast”). The four threshold values I_th1_L, I_th2_L, I_th1_H, and I_th2_H are set so as to be larger than ΔI_th_L).

  Accordingly, when the lamp 12 is turned off after being turned on from the turned off state, and when the lamp 12 is turned on after being turned off from the turned on state, the ambient illuminance I is larger (larger). Needs to change).

  Here, FIG. 5B shows the case where the first threshold value I_th1 and the second threshold value I_th2 are set to the low contrast threshold values I_th1_L and I_th2_L, respectively, in the case where the temporal change in the ambient illuminance I is the same. FIG. 10 is a diagram for comparing differences in the state of the lamp body 12 when each of the first threshold value I_th1 and the second threshold value I_th2 is set to each of the high contrast threshold values I_th1_H and I_th2_H. In FIG. 5B, the horizontal axis is time, and the vertical axis is ambient illuminance I.

  The time change of the ambient illuminance I in FIG. 5B exemplifies a case where the ambient illuminance I frequently changes greatly due to the influence of a shadow of a building or the like when the vehicle travels in fine weather.

  When each of the first threshold value I_th1 and the second threshold value I_th2 is set to each of the low contrast threshold values I_th1_L and I_th2_L, at five time points of time point t21, time point t24, time point t25, time point t26, and time point t27, The lamp 12 is switched from one of the off state and the on state to the other. On the other hand, when each of the first threshold value I_th1 and the second threshold value I_th2 is set to each of the high contrast threshold values I_th1_L and I_th2_L, the lamp body 12 is turned off at two time points t22 and t23. The lighting state is switched from one to the other.

  In this way, when the vehicle travels in fine weather, by increasing the threshold difference, even when the ambient illuminance I frequently changes greatly due to the influence of the shadow of the building or the like, It is possible to suppress frequent turn-off (in the example of FIG. 5B, the number of times of switching is reduced from 5 times to 2 times).

  Further, the low contrast thresholds I_th1_L and I_th2_L are set to be higher than the high contrast thresholds I_th1_H and I_th2_H, respectively. Thereby, when the contrast CR is low (for example, when the weather condition is cloudy (FIG. 7B) or stormy weather (FIG. 7C)), when the contrast CR is high (for example, the weather condition is clear) The first threshold value I_th1 and the second threshold value I_th2 are higher than (in the case of FIG. 7A).

  When the first threshold I_th1 is increased, the periphery of the vehicle C is relatively bright (when the ambient illuminance I is high. For example, in the daytime, the ambient illuminance I is high even in cloudy and stormy weather). In contrast, when the contrast CR is low, the lamp body 12 easily changes from the unlit state to the lit state.

  Further, since the second threshold value I_th2 is increased, the lamp body 12 is maintained in the lighting state when the contrast CR is low even when the periphery of the vehicle C is relatively bright (when the ambient illuminance I is high). It becomes easy.

  As described above, the low-contrast threshold values I_th1_L and I_th2_L are set to be higher than the high-contrast threshold values I_th1_H and I_th2_H, respectively. Even when the driver is willing to output the illumination light outward by the lamp body 12 or when it is desirable to output the lamp body 12 in a state where the contrast CR is low. Can be turned on, or the lighting state can be maintained.

  Further, in the present embodiment, it is determined whether or not the contrast CR of the captured image Img is low based on the image information of each region of the sky region A1, the road surface region A2, and the front region A3 extracted from the captured image Img. Yes. Thereby, buildings around the road on which the vehicle C is traveling (the image portion of the building is partly included in the front area A3 but not included in the sky area A1 and the road surface area A2), etc. It is possible to determine whether or not the contrast CR is low (that is, determine the state of the field of view) with higher accuracy by reducing the influence.

  Here, steps ST <b> 101 to ST <b> 105 correspond to processing executed by the contrast detection unit 82. Steps ST106 to ST108 correspond to processing executed by the threshold changing unit 83.

  In the present embodiment, after calculating image information in each of the sky region A1, the road surface region A2, and the front region A3, it is determined whether or not the contrast CR is low based on the image information of each region. However, the determination is not limited to this. For example, it may be determined whether or not the contrast is low based on image information (such as luminance dispersion) of the entire image without dividing the image into regions.

  Further, the contrast detection method is not limited to the method of calculating and detecting image information as in the present embodiment, and various methods may be used. For example, the contrast detection method may be a method of detecting contrast based on a ratio or difference between the maximum value and the minimum value of the luminance of the image (or each region).

  Another contrast detection method by the vehicle lamp control device will be described with reference to FIG. FIG. 8 is a histogram showing the luminance distribution of an image (specifically, each region). FIG. 8A is an example when the contrast CR is low, and FIG. 8B is an example when the contrast CR is high. Are shown respectively. 8A and 8B, the horizontal axis represents luminance, and the vertical axis represents the number of pixels.

  In the detection method, the vehicle lamp control device has a predetermined ratio (for example, the predetermined ratio is defined as 80%) or more of the number of pixels in the image (specifically, each region). It is determined that the contrast CR is low when the width of the luminance range occupying the number is equal to or smaller than a predetermined width (for example, when the weather is cloudy or stormy as shown in FIG. 7B or 7C). When the width is larger than the predetermined width (for example, when the weather condition is fine as shown in FIG. 7A), it is determined that the contrast CR is high.

  In the present embodiment, the first threshold is set so that the difference between the first threshold and the second threshold (that is, the threshold difference) differs between when the contrast is relatively high and when the contrast is relatively low. Although the threshold and the second threshold are set, the present invention is not limited to this. For example, the threshold difference may be kept constant regardless of the contrast. Further, the threshold difference may be 0 (that is, the first threshold and the second threshold are the same value).

  Further, the first threshold value and the second threshold value may be set so that the threshold difference becomes 0 when the contrast is low and the threshold difference becomes a value larger than 0 when the contrast is high.

  Further, in the present embodiment, only two (two steps) determination is made as to whether the contrast CR is low or high (that is, each of the first threshold value and the second threshold value is only two). The height may be determined in three or more stages. In this case, when the contrast is relatively low, the first threshold value and the second threshold value are set so that at least one of the first threshold value and the second threshold value is higher than when the contrast is relatively high. Is set.

  For example, the relative level of the contrast is determined in three stages of “low contrast”, “normal contrast”, and “high contrast”, and each of the first threshold value and the second threshold value is determined according to each stage. Three may be used. In this case, the first threshold value is set so that at least one of the first threshold value and the second threshold value increases in the order of “when contrast is high” → “when contrast is normal” → “when contrast is low”. And the second threshold value is set.

  In the present embodiment, as a method for detecting the brightness around the vehicle C, the brightness around the vehicle C is detected based on the illuminance I output from the illuminance sensor 2. Not limited to. For example, the brightness of the periphery of the vehicle C may be detected based on the brightness of the captured image Img of the camera 11 (for example, the brightness of the captured area).

  DESCRIPTION OF SYMBOLS 1 ... Lamp control device (vehicle lamp control device), I ... Ambient illumination (brightness around the vehicle), I_th1 ... First threshold, I_th2 ... Second threshold, C ... Contrast, Img ... Captured image (taken Image), C ... Vehicle, 11 ... Camera, 12 ... Lamp, 2 ... Illuminance sensor, 81 ... Lamp control unit, 82 ... Contrast detection unit, 83 ... Threshold change unit.

Claims (6)

A lamp control unit that controls lighting or extinction of the lamp that outputs illumination light to the outside of the vehicle according to the brightness of the surroundings of the vehicle;
A contrast detector for detecting the contrast of an image around the vehicle imaged by a camera mounted on the vehicle;
A first threshold that is a threshold of the brightness that causes the lamp control unit to change the lamp from a light-off state to a lighting state, and the brightness that causes the lamp control unit to change the lamp from a lighting state to a light-off state. A vehicle lamp control device comprising: a threshold value changing unit that changes at least one of the second threshold values, which is a threshold value, according to the contrast detected by the contrast detection unit.   2. The vehicle lamp control device according to claim 1, wherein the threshold value changing unit determines the level of contrast detected by the contrast detection unit, and the detected level is detected when the detected contrast is relatively low. It is configured to change at least one of the first threshold and the second threshold so that at least one of the first threshold and the second threshold is higher than when the contrast is relatively high. A vehicle lamp control device characterized by comprising: In the vehicle lamp control device according to claim 1 or 2,
The second threshold is set to a value higher than the first threshold,
The lamp control unit changes the lamp from a light-off state to a light-on state when the brightness is higher than the first threshold value and lower than the first threshold value, and The lamp is configured to change from a lighting state to a non-lighting state when the brightness changes from a lower brightness than the second threshold to a brightness equal to or higher than the second threshold. Vehicle lamp control device.   4. The vehicle lamp control device according to claim 3, wherein the threshold value changing unit determines the level of contrast detected by the contrast detection unit, and the detected level is detected when the detected contrast is relatively high. It is configured to change at least one of the first threshold and the second threshold so that the difference between the first threshold and the second threshold is larger than when the contrast is relatively low. A vehicle lamp control device characterized by the above. In the vehicle lamp control device according to any one of claims 1 to 4,
An illuminance sensor that generates an output corresponding to the brightness;
The vehicle lamp control device, wherein the lamp control unit is configured to detect the brightness based on an output of the illuminance sensor.   The vehicle lamp control device according to any one of claims 1 to 4, wherein the lamp control unit is configured to detect the brightness based on a luminance of an image captured by the camera. A vehicle lamp control device characterized by comprising: