JP2008170785A - In-car display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control the brightness of a display screen in an in-car display device so that images displayed on the display screen can be always easily viewed. <P>SOLUTION: The average brightness of green in a predetermined time (corresponding to one frame) is detected from video signals by an image characteristic detecting section 32, as well as an average area of the pupil of a user for a predetermined time is measured by a pupil measuring section 29; and the brightness of a backlight 12 of a liquid crystal panel 10 is determined based on the green brightness and the pupil area. Thereby, the brightness of the liquid crystal panel 10 decreases with the higher brightness of the video signals and the larger pupil, and on the other hand, the brightness of the liquid crystal panel 10 increases with the lower brightness of the video signals and the smaller pupil. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an in-vehicle display device, and more particularly to a display device in which the brightness of a display screen is adjusted in accordance with the degree of image brightness and the size of a user's pupil.

  For example, a car navigation apparatus generally uses a liquid crystal display with a backlight as a display. And in patent document 1, the illumination intensity measurement means which measures the illumination intensity around a display is provided, and the brightness of a backlight is made high or low by detecting the difference between day and night by this illumination intensity measurement means. The screen is too dark to be seen, and conversely it is too bright and dazzling.

However, since the brightness adjustment method of the display screen of Patent Document 1 is to adjust the brightness of the display screen in two stages according to the ambient brightness, there are many street lamps, neon lights, etc. even at night. When traveling in a bright downtown area, the display screen may feel dark. In order to solve this problem, in Patent Document 2, the size of a pupil of a person who views the display screen is detected, and the brightness of the display screen is adjusted so that the pupil has a predetermined size (set value). Adjustment, that is, when the pupil becomes larger, the luminance of the display screen is increased, and when the pupil becomes smaller, the luminance of the display screen is decreased.
Japanese Unexamined Patent Publication No. 7-117559 JP 2002-351443 A

  In the configuration of Patent Document 2, for example, when light from the headlight of an oncoming vehicle enters the driver's eyes when traveling at night, the pupil is narrowed down to reduce the amount of incident light. On the other hand, since the pupil is reduced on the display side, the luminance of the display screen is lowered in order to return the pupil to the original set value. However, when the light of the headlight enters the eyes and the pupil becomes small, the display screen must be brightened to increase the amount of light entering the user's eyes. The display screen is darkened, and the displayed content becomes more difficult to see.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an in-vehicle display device capable of adjusting the brightness of a display screen so that an image displayed on the display screen can be always viewed easily. Is to provide.

In the first aspect of the present invention, the luminance of the video is detected from the video signal, the size of the pupil of the user is measured, and the luminance of the display screen is controlled based on the luminance and the size of the pupil. The higher the luminance and the larger the pupil, the lower the luminance of the display screen. Conversely, the lower the luminance of the video signal and the smaller the pupil, the higher the luminance of the display screen.
For this reason, when the surroundings are dark and the pupil is large, the brightness of the display screen can be kept low, so there is no fear that the display screen will be too bright. Also, when the surroundings are bright or the pupils are small due to the headlights of oncoming vehicles at night, the brightness of the display screen is increased, so the display screen is too dark and difficult to see Can be effectively prevented from occurring.

  In the invention of claim 2, since the pupil size is calculated as an average value or an integrated value at a predetermined time, and the brightness of the display screen is controlled using the average value or the integrated value, Changes in the size of the pupil, for example, when the passing light of the following vehicle is reflected on the rear-view mirror and enters the user's eyes, the pupil size decreases momentarily. Change can be eliminated.

  In the invention of claim 3, when the size of the pupil measured this time exceeds or exceeds the limit value than the size of the pupil measured last time, the size of the pupil measured this time is set to the size of the pupil measured last time. Since the value is corrected to a value larger or smaller than the size by a predetermined value, a sudden luminance change of the display screen can be more effectively prevented.

  In the invention of claim 4, as the luminance of the video signal is higher, the luminance difference of the bright gradation side is expanded and displayed on the display screen, and as the luminance of the video signal is lower, the gradation of the lower gradation side is displayed. Since the brightness difference is expanded and displayed on the display screen, the video can be displayed more clearly.

  In the invention of claim 5, the brightness of the display screen is controlled by preferentially using the size of the pupil of the user sitting in the darker seat among the driver seat side and the passenger seat side. This is because people in dark places are more sensitive to changes in brightness, so they controlled the brightness of the display screen using the size of the pupil of the user sitting in the dark side of the seat. The display screen can be easily viewed by both the user and the user sitting in the passenger seat.

  Hereinafter, an embodiment in which the present invention is applied to a display device (vehicle display device) of a car navigation device will be described with reference to the drawings. As shown in FIG. 2, the car navigation device 1 includes a navigation unit 2, a display 3, a position detection unit such as a GPS (Global Positioning System), a map data storage unit, etc. For controlling the input unit 4 and the speaker 5, which are composed of a mechanical switch provided around the display screen of the display 3, a touch panel provided on the display screen, a remote control sensor paired with a remote control, and the like, and the whole. A control device 6 is provided as control means.

  Further, the car navigation apparatus 1 is configured as an audio video integrated type incorporating a video crisis such as an audio device (not shown) such as a radio receiver or a CD player, a DVD player 7 or a television receiver 8. Yes. Further, in this embodiment, a rear photographing camera 9 for photographing the rear is provided at the rear of the vehicle, and the rear photographing camera 9 is connected to the control device 6 of the car navigation apparatus 1. Then, by the operation of the input unit 4, the display 3 is used for displaying an original road map, used for displaying a playback image by the DVD player 7, or a TV broadcast image received by the TV receiver 8. Or for displaying video captured by the rear camera 9 when the vehicle is back.

  That is, when the car navigation device 1 is originally used, the control device 6 acquires the current position from the position detection unit of the navigation unit 2, and acquires map data centered on the current position from the map data storage unit. A video signal is generated based on the acquired map data, and a road map is displayed on the display 3, and the current position is displayed on the road map. In addition, when the DVD player 7 plays a DVD, receives a television broadcast, or captures the rear camera 9, the control device 6 acquires a video signal from the DVD player 7, the television receiver 8, or the rear camera 9. The video is displayed on the display 3.

  In the present embodiment, the display 3 includes a liquid crystal display. As shown in FIG. 1, the display 3 is a full-color liquid crystal panel 10 as a display screen, and a liquid crystal panel drive circuit (panel) that drives the liquid crystal panel 10. Drive means) 11, a backlight 12 as a light source for illuminating the liquid crystal panel 10, and a backlight drive circuit (light source drive means) 13 for driving the backlight 12. When the video signal is input, the backlight driving circuit 13 drives the green, blue, and red liquid crystals to form a color image.

  In the liquid crystal panel 10, the γ value for brightness adjustment (γ correction) is set to a certain value in advance. In a normal case, a signal (luminance signal) relating to the luminance in the video signal is used. By correcting this γ value and displaying it on the liquid crystal panel 10, the image can be clearly seen. In the liquid crystal panel 10 of this embodiment, the γ value is set to 2.2, for example. The larger the γ value, the brighter the image is displayed (provided that 1 <γ).

  In this embodiment, when displaying a road map image, a DVD playback image, a television image, or a captured image of the rear camera 9 on the display 3, the luminance of the liquid crystal panel 10 (the luminance of the backlight 12) is set. The change control can be performed based on the size of the pupil of the user and the luminance of the video represented by the video signal. The luminance change control of the liquid crystal panel 10 can be arbitrarily selected by operating the input unit 4.

  In the luminance change control of the liquid crystal panel 10, the size of the user's pupil is obtained based on the video captured by the camera. In addition, the luminance of the video represented by the luminance signal of the video signal (the degree of brightness of the video) is that the color most sensitive to humans is green, so the luminance signal for green, red, and blue Among them, the luminance signal for green is acquired as the luminance of the video represented by the video signal.

  A system for controlling the brightness of the backlight 12 from the pupil size and the green brightness information will be described below. As shown in FIG. 2, the control device 6 is constituted by a microcomputer system including a CPU 14, a ROM 15, a RAM 16, and the like. In addition to the navigation unit 2, the display unit 3, the input unit 4, the speaker 5, the DVD player 7, the television receiver 8, and the rear camera 9, the control device 6 includes a driver seat side illuminance sensor 17, A passenger seat side illuminance sensor 18, a driver seat side camera 19, and a passenger seat side camera 20 are connected.

The driver seat side illuminance sensor 17 and the passenger seat side illuminance sensor 18 function as illuminance detection means for detecting the brightness of the driver seat side and the passenger seat side, respectively, and as shown in FIG. Above, it is provided in front of the driver's seat 22 and in front of the passenger seat 23. Further, the driver seat side camera 19 and the passenger seat side camera 20 function as photographing means for photographing the eyes of the user sitting on the driver seat 22 and the user sitting on the passenger seat 23, respectively, and are shown in FIG. Thus, it is attached to the base portion 25a of the room mirror 25 disposed in the upper center of the front windshield glass 24 of the automobile.
As shown in FIG. 4, both cameras 19 and 20 include an infrared light emitting unit 26 that emits infrared light, and an infrared area sensor 27 as a light receiving unit configured by arranging infrared light receiving elements vertically and horizontally. Infrared light emitted from the infrared light emitting unit 26 enters the user's eyes E through the pupil thereof, is reflected by the fundus, and forms an image (receives light) on the infrared area sensor 27.

  FIG. 1 shows the control device 6 as a functional block. As shown in FIG. 1, the control device 6 includes a determination unit 28 as a determination unit, a pupil measurement unit 29 as a pupil measurement unit, a luminance control unit 30 as a luminance control unit, and a backlight luminance as a luminance conversion storage unit. A conversion table 31, an image feature detection unit 32 as a video luminance detection unit, a video signal control unit 33 as a video signal control unit, and a video signal conversion table 34 as a modified signal conversion storage unit are provided. The backlight luminance conversion table 31 and the video signal conversion table 34 are composed of, for example, the ROM 15.

  A video signal for displaying a video on the display 3 is given to the image feature detection unit 32 and the video signal control unit 33. The video feature detection unit 32 acquires a green luminance signal from the luminance signal of the video signal, calculates an average value of the green luminance for one frame of the video signal, for example, and uses the result as the luminance of the video. The data is input to the control unit 30 and the video signal control unit 33.

  In this case, since the time required for one frame is 16.7 ms, the video feature detection unit 32 calculates the average value of the green luminance per 16.7 ms (predetermined time). In addition, the luminance signal is configured as a signal in which the luminance is divided into 256 gradations, and the luminance for each pixel of green, red, and blue is expressed by gradation. By calculating the average of the gradation for one green frame pixel from such a luminance signal, the degree of brightness (luminance) of the video represented by the video signal can be calculated.

  On the other hand, detection signals from both the illuminance sensors 17 and 18 are input to the determination unit 28. The determination unit 28 compares the detection signals input from the illuminance sensors 17 and 18, determines which illuminance is lower, and inputs the determination result to the pupil measurement unit 29. The pupil measurement unit 29 also receives captured image signals (captured image information) of both the drivers 19 and 20 on the driver's seat side and the passenger seat side. The pupil measurement unit 29 includes a selection unit 35, an image analysis unit 36, and a pupil area calculation unit 37. The determination result of the determination unit 28 and the captured image signals of both cameras 19 and 20 are both selection units 35. Given to.

  The selection unit 35 selects a captured image signal from the camera on the side corresponding to the determination result of the determination unit 28 among the cameras 19 and 20 on the driver's seat side and the passenger's seat side, and provides the selected image signal to the image analysis unit 36. The image analysis unit 36 analyzes the captured image signal and measures the pupil diameter. Next, based on the pupil diameter, the pupil area calculation unit 37 calculates the pupil area, and outputs this pupil area to the luminance control unit 30 as pupil size information.

  In this embodiment, the pupil area output from the pupil area calculation unit 37 is an average value within a predetermined time. In this case, the predetermined time during which the pupil area calculation unit 37 calculates the average pupil area is the same as the predetermined time during which the image feature detection unit 32 calculates the average value of the luminance of one frame of the video signal. The start and end of the predetermined time calculated by the image feature detection unit 32 and the pupil area calculation unit 37 are synchronized with each other.

  The luminance control unit 30 sets the average value of the pupil area input from the pupil measurement unit 29 and the average value of the green luminance input from the image feature detection unit 32 to a predetermined large (high), medium, small It is determined which of the three (low) ranges is entered, and the backlight luminance is determined with reference to the backlight luminance conversion table 31 based on the determined luminance range and pupil area range. That is, the backlight luminance conversion table 31 stores a conversion matrix for setting the luminance of the backlight 12 from the relationship between the luminance range and the pupil area range, as shown in FIG. Then, the luminance control unit 30 obtains the luminance of the backlight 12 based on this conversion matrix, and gives a drive signal to the backlight driving circuit 13 so as to obtain the obtained luminance. In the matrix shown in FIG. 8, when the average value of the green gradation is constant or when the average pupil area is constant, the larger the number, the higher the luminance is set. Accordingly, for example, 2 and 4, 3 and 5 and 7, and 6 and 8 are not necessarily higher in luminance as the number is larger, and the height is appropriately set by experiment or the like.

  The video signal control unit 33 determines whether the average value of the green luminance acquired from the image feature detection unit 32 falls in any of three preset ranges of large (high), medium, and small (low). Then, based on the determined luminance range, the γ value is determined with reference to the video signal conversion table 34. That is, in the video signal conversion table 34, when the average value of the green luminance falls within the middle range, the γ value is set to 2.2 which is a predetermined value, and the average value of the green luminance is large. When entering the range, the γ value is set to a predetermined value larger than 2.2, and when the average value of the green luminance is within the small range, the γ value is set to a predetermined value smaller than 2.2. It is like that.

  When the γ value is determined, the video signal control unit 33 corrects the luminance signal of the video signal with the γ value, and inputs the corrected video signal to the liquid crystal panel drive circuit 11. The brightness of the light and dark gradation after the correction is as shown in FIG. That is, the brightness signal brightness (brightness) is divided into 256 gradations as described above, but when the brightness of each gradation is corrected by the γ value, when the γ value is 2.2, a normal video image is obtained. The luminance of each gradation is set as shown by the curve A in FIG. 9 so that the image can be clearly seen with respect to the signal.

  Further, when the γ value is smaller than 2.2 (video darker than a normal video signal), as shown by a curve B in FIG. When the gamma value is larger than 2.2 (brighter than the normal video signal), the brightness difference between the bright-side gradations increases and the brightness of the bright part becomes clearer. So that they can be distinguished.

  The operation of the following configuration will be described with reference to the flowcharts of FIGS. When displaying a map video by the navigation unit 2, a playback video by the DVD player 2, a television broadcast video by the television receiver 8, or a video shot by the rear camera 9 on the liquid crystal panel 10 of the display 3, the user It is selected whether to control the luminance of the two or two-day control of day and night without changing control. When the mode for automatically changing and controlling the luminance of the liquid crystal panel 10 (automatic light control mode) is selected, the control device 6 sets the luminance of the backlight 12 to the luminance of the video represented by the video signal, the user's pupil, and the like. In addition to automatic change control according to the luminance level of the video signal, the γ value is changed according to the luminance of the video represented by the video signal, so that it can be adjusted so that the user can easily see whether it is a dark screen or a bright screen. ing.

  That is, when the car navigation device 1 is powered on, the control device 6 executes the backlight luminance conversion routine of FIG. 5 and the γ value conversion routine of FIG. When the routine of FIG. 5 is entered, the control device 6 determines whether or not the automatic dimming mode is set (step S1), and when the automatic dimming mode is set (“YES” in step S1). First, the determination unit 28 determines whether or not the detected illuminance of the passenger-side illuminance sensor 18 is higher than the detected illuminance of the driver-seat-side illuminance sensor 17 (step S2), and the determination result is used as the pupil measurement unit 29. To the selection unit 35.

  In the selection unit 35, based on the determination result of the determination unit 28, when the passenger side illuminance is higher (the driver side is darker) ("YES" in step S2), the video information of the driver side camera 19 is displayed. Is selected and given to the image analysis unit 36. The image analysis unit 36 analyzes the image information of the driver's seat side camera 19 and determines whether or not the pupil can be detected (step S3). For example, if the driver who is the subject is moving his / her face to the left or right or looking down, the pupil may be blurred or the pupil may not be visible, so the pupil cannot be detected. It becomes impossible (“NO” in step S3).

  When the pupil can be detected (“YES” in step S3), the pupil area calculation unit 37 measures the pupil diameter, and calculates the pupil area from the diameter (step S4). In this case, the pupil area may be obtained directly from the number of pixels of the pupil. The measurement of the pupil area is repeatedly performed at a predetermined time interval for a predetermined time (a time corresponding to one frame). At the time of measuring the pupil area within the predetermined time, the pupil area calculation unit 37 determines whether or not the pupil area is normally measured (step S5). For example, if the subject to be photographed moves his / her face while measuring the pupil area, the pupil area cannot be measured normally. When the measurement of the pupil area over a predetermined time is normally completed (“YES” in step S6), the pupil area calculation unit 37 calculates the average value of the measured pupil areas (step S7), and then in FIG. As shown, it is calculated how much the average pupil area S1 of the current measurement has changed from the average pupil area S2 of the previous measurement, and whether or not the change width ΔS is within the limit value ΔL, that is, the average pupil area measured last time. It is determined whether it is larger or smaller than the limit value ΔL (step S8).

  FIG. 7 shows a case where the change width ΔS of the average pupil area S1 measured this time is within the limit value ΔL. When the change width ΔS of the average pupil area is within the limit value ΔL (“YES” in step S8), the pupil area calculation unit 37 calculates the average pupil area within the predetermined time measured this time as the size of the pupil. Information is given to the luminance control unit 30 (step S9). When the fluctuation range ΔS of the average pupil area exceeds the limit value ΔL (“NO” in step S8), the pupil area calculation unit 37 adds a predetermined value, for example, the limit value ΔL (exceeds ΔL) to the previous average pupil area. Or a value obtained by subtracting a predetermined limit value ΔL from the previous average pupil area (if it has changed below ΔL) is determined as the current average pupil area (step S10). This is given to the luminance control unit 30 as pupil size information. If the measurement of the pupil area is not normally performed (“NO” in step S3, “NO” in step S5), the average pupil area of the previous measurement is transmitted to the luminance control unit 30 as pupil size information. (Step S11).

  On the other hand, when the driver side illumination is higher (the passenger side is darker) ("YES" in step S2), the pupil measurement unit 29 is based on the video information of the passenger side camera 20 as described above. Similarly, the average pupil area within a predetermined time of the subject person (person sitting in the passenger seat) is obtained and given to the luminance control unit 30 (steps S12 to S20).

  If the pupil of the passenger seat cannot be detected at the beginning of the measurement of the average pupil area (“NO” in step S12), it is possible that there is no person in the passenger seat. The camera is switched from the passenger side camera 20 to the driver side camera 19 to obtain the average pupil area of the person sitting in the driver's seat. If the pupil is detected but the pupil area cannot be measured within a predetermined time thereafter, the average pupil area of the previous measurement is used as the pupil size information to the luminance control unit 29. ("NO" in step S14, step S20). Further, when the change width ΔS of the average pupil area measured this time exceeds a predetermined value ΔL, ΔL is added to the previous average pupil area or ΔL is subtracted from the previous average pupil area in the same manner as described above. The area is given to the luminance control unit 29 as pupil size information (“NO” in step S17, step S19).

  The average value of the green luminance is calculated from the luminance signal of the video signal in parallel with the above pupil area measurement. That is, when the γ value changing routine of FIG. 6 is entered, the control device 6 determines whether or not the automatic light control mode is set (step A1). When the automatic light control mode is selected (“YES” in step A1), first, the image feature detection unit 32 detects the green luminance from the luminance signal of the video signal and obtains the average per frame. This green luminance average value is given to the video signal control unit 33 (step A2) and also to the luminance control unit 30 (step S21 in FIG. 5).

  In the luminance control unit 30, the backlight luminance conversion table 31 is referred to, and the backlight 12 corresponding to the average green luminance value given from the image feature detection unit 32 and the average pupil area value given from the pupil measurement unit. The brightness is determined, and the brightness is output to the backlight drive circuit 13 (step S22). For example, when the average pupil area is large and the average green luminance value is medium, the luminance of the backlight is determined as “6”.

  Further, the video signal control unit 33 refers to the video signal conversion table 34 to determine the γ value corresponding to the green luminance average value given from the image feature detection unit 32 (step A3). For example, when the green luminance average value is the reference value, the γ value is determined to be 2.2. In addition, when the green luminance average value is lower than the reference value (when dark), it is determined to be a predetermined value larger than 2.2. Conversely, when the green luminance average value is higher than the reference value (when bright), 1 .2 is determined to be a predetermined value smaller than 2. Then, the video signal control unit 33 sends the video signal to the liquid crystal panel driving circuit 11 of the display 3 as a luminance signal after correcting the luminance signal of the video signal with the determined γ value. Thus, the voltage applied to the liquid crystal pixels of each color is controlled to be high and low so that the luminance (intensity) of the image becomes the luminance corrected by the γ value. Will be done.

  As described above, according to the present embodiment, in the display device 3, the backlight drive circuit 13 controls the luminance of the backlight 12 so as to obtain the luminance given from the luminance control unit 30. For this reason, when the headlight of the oncoming vehicle enters the driver's eyes and the pupil becomes smaller during night driving, the brightness of the backlight 12 increases, so the video displayed on the display 3 Even when the brightness is high and the display 3 is viewed with the light of the headlights in the eyes, the image can be recognized more clearly. Further, since the brightness of the backlight is controlled according to the brightness of the image based on the brightness signal of the image signal, the brightness of the backlight 12 is lowered when displaying a bright image in the daytime at night. , Prevents feeling dazzling.

  Moreover, since the pupil area, which is one factor that determines the luminance of the backlight 12, is an average value within a predetermined time, for example, the passing light of the succeeding vehicle is reflected by the room mirror 25 and appears in the eyes for a short time. In this case, since the luminance change of the backlight 12 is suppressed so as not to occur, an instantaneous luminance change of the liquid crystal panel 10 can be prevented.

  In addition, when the average value of the pupil area obtained this time fluctuates beyond the limit value ΔL from the average value of the previous pupil area, a value obtained by adding or subtracting the limit value ΔL to the average value of the previous pupil area Is the average value of the pupil area this time, it is possible to more effectively prevent a rapid luminance change of the liquid crystal panel 10.

  Further, the liquid crystal panel drive circuit 11 controls the liquid crystal panel 10 based on the video signal given from the video signal control unit 33 to display an image. That is, when the image is dark, the luminance difference between the lower light and dark gradations is increased by increasing the γ value. Therefore, for example, when the vehicle is moved back, the image captured by the rear camera 9 is displayed on the display 3. In the case of the display, even when a person wearing black clothes passes behind the vehicle, the person's movement can be recognized more clearly.

The present invention is not limited to the embodiments described above and shown in the drawings, and can be expanded or changed as follows.
The size of the pupil does not necessarily have to be an average value for a predetermined time.
The size of the pupil may be indicated by the pupil diameter.
The measurement of the size of the pupil may be limited only to the user sitting in the driver's seat.
The luminance (degree of brightness) of the video detected from the luminance signal of the video signal is not limited to the average value of one frame.
The display is not limited to a liquid crystal display, and may be a plasma display, an EL (electroluminescence) display, or the like.

The functional block diagram of the principal part which shows one Embodiment of this invention Block diagram showing electrical configuration Perspective view of the front of the car Cross section of a camera that captures the pupil Backlight brightness conversion flowchart Flow chart for changing γ correction value Graph showing changes in pupil area Conceptual diagram showing a table configuration for determining backlight luminance based on an average value of green luminance and an average value of pupil area The figure which shows the brightness change of the light and dark gradation with the change of γ value

Explanation of symbols

  In the figure, 3 is a display, 6 is a control device, 10 is a liquid crystal panel (display screen), 11 is a backlight, 13 is a backlight drive circuit, 17 is a driver's seat side illuminance sensor (illuminance detection means), and 18 is an assistant. Seat side illuminance sensor (illuminance detection means), 19 is a driver's seat side camera, 20 is a passenger seat side camera, 28 is a determination unit (determination unit), 29 is a pupil measurement unit (pupil measurement unit), and 30 is a luminance control unit ( (Brightness control means), 31 is a backlight luminance conversion table, 32 is an image characteristic detection unit (video luminance detection means), 33 is a video signal control unit (video signal control means), 34 is a video signal conversion table, and 35 is a selection unit. , 36 is an image analysis unit, and 37 is a pupil area calculation unit.

Claims (5)

In a vehicle-mounted display device that is mounted on a vehicle and displays a video on a display screen based on a video signal,
Video luminance detection means for detecting the luminance of the video from a signal relating to luminance among the video signals;
Pupil measurement means for measuring the size of the user's pupil;
A vehicle-mounted display device comprising: brightness control means for controlling the brightness of the display screen in accordance with the brightness of the video detected by the video brightness detection means and the size of the pupil measured by the pupil measurement means.   The in-vehicle display device according to claim 1, wherein the pupil measurement unit calculates the size of the pupil as an average value or an integrated value within a predetermined time.   When the pupil size measured this time is larger or smaller than the pupil size measured last time, exceeding the limit value, the pupil size measured this time is used as the pupil of the previous measurement. The in-vehicle display device according to claim 1, wherein the in-vehicle display device is corrected to a value that is larger or smaller by a predetermined value than the size of. Among the video signals, a signal related to luminance is a form that represents the luminance for each gradation by dividing light and dark into a plurality of gradations,
The higher the brightness detected by the video brightness detection means, the wider the brightness difference of each tone on the bright tone side of the signal related to the brightness, and the lower the detected brightness, the lower the tone of the signal related to the brightness. 4. A vehicle-mounted display device according to claim 1, further comprising video signal control means for expanding the luminance difference on the side. Illuminance detection means capable of detecting the illuminance on the driver's seat side and the illuminance on the passenger seat side;
Determination means for determining which one of the driver seat side and the passenger seat side has high illuminance based on the illuminance on the driver seat side and the illuminance on the passenger seat side detected by the illuminance detection means;
The pupil measurement means can measure the size of the pupils of both the user sitting in the driver's seat and the user sitting in the passenger's seat, and is reduced by the determination means on the driver seat side and the passenger seat side. The in-vehicle display device according to any one of claims 1 to 4, wherein the vehicle-mounted display device is configured to measure a size of a pupil of a user who is seated on a side determined to be an illuminance side.

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