JP5590412B2 - Projection system and face photographing system - Google Patents

Description

  The present invention relates to a light projecting system that projects near-infrared light onto a user's face and a face photographing system that captures a user's face projected with near-infrared light.

  2. Description of the Related Art Conventionally, there has been known a driver monitor system that captures a face of a driver of a vehicle and detects a driver's face orientation or an eye opening based on the photographed image. In the driver monitor system, a projector that projects near-infrared light onto the driver's face and a camera that captures the driver's face are provided. The camera is provided with a visible light cut filter that cuts visible light. According to this driver monitor system, the near infrared light from the projector is reflected by the driver's face, and the reflected near infrared light is received by the camera to photograph the driver's face. Thus, by using near infrared light, it is possible to prevent the driver from feeling dazzling light from the projector, and the driver's face can be clearly photographed regardless of day or night.

  Conventionally, a point light source projector such as an LED has been used as a projector used in a driver monitor system, which causes a problem of uneven illuminance when light is projected onto a driver's face. Here, FIG. 11 is a diagram for explaining illuminance unevenness in a conventional projector, and specifically, FIG. 11A is a diagram showing a state in which light is emitted from the conventional projector 100, FIG. 11B is a diagram showing the light intensity distribution by the projector 100 two-dimensionally, and FIG. 11C is a diagram showing the light intensity distribution by the projector 100 three-dimensionally. In FIG. 11A, a projector 100 including a point light source 101 is shown. Further, in FIG. 11A, the center line CL of the point light source 101 is shown. Further, in FIG. 11B, the darker the color, the stronger the light intensity, and the center line CL shown in FIG. 11A is also shown. Further, FIG. 11C shows that the light intensity increases as it increases in the vertical axis direction, and the center line CL shown in FIG. 11A is also shown.

  As shown in FIG. 11A, the near-infrared light L1 is emitted from the point light source 101 so as to radiate forward. Therefore, the near-infrared light L1 from the point light source 101 is the strongest in front of the point light source 101 (on the center line CL) as shown in FIGS. 11B and 11C, and the intensity distribution is uniform. It is not. That is, illuminance unevenness occurs when the face of the driver is irradiated. When uneven illuminance occurs, it may be difficult to recognize the driver's face from the captured image.

  Therefore, in order to solve the above problems, it is conceivable to employ a projector of a surface light source that emits light on a surface instead of a point light source. For example, Patent Document 1 discloses an invention of an illumination system (surface light source) for a backlight of a liquid crystal display. Further, in Patent Document 2, a light source that emits near-infrared light for blood vessel authentication is provided in a backlight for a sub display (liquid crystal display) of a mobile phone, and a blood vessel authentication (biological information) is performed by holding a finger over the sub display. An invention that can be authenticated) is disclosed. That is, in the invention of Patent Document 2, biometric authentication can be performed on the sub-display of the mobile phone in addition to displaying an image.

Special table 2009-524911 International Publication No. 2008/062544

  However, since the backlight of the display device (liquid crystal display) as in Patent Document 1 does not emit near-infrared light, the backlight is used as it is as a projector that projects near-infrared light onto the face of a user such as a driver. It is not possible. Patent Document 2 discloses a surface light source that emits near-infrared light. Since the surface light source is a backlight for a sub-display of a mobile phone, a projector that projects light onto a user's face. Cannot be used as On the other hand, if a surface light source is provided only to project near-infrared light on the user's face, the system configuration becomes complicated.

  The present invention has been made in view of the above problems, and a projection system capable of uniformly projecting near-infrared light onto a user's face while simplifying the system configuration and the near-infrared light are projected. It is an object to provide a face photographing system for photographing a user's face.

In order to solve the above problems, a light projecting system according to the present invention includes a panel-shaped display unit, a light source unit that emits light to the display unit, and a light source unit provided in front of an area where a user's face is located. Near the user's face, comprising a display device including a drawing control means for drawing an image corresponding to the emitted light on the display unit by controlling the emitted light emitted from the display unit among A floodlight system that projects outside light,
The light source unit is configured to emit near infrared light,
The drawing control unit, while drawing an image on the display unit, Ru is emitted from the display unit of the near-infrared light.

  According to this, the light projection system is configured using the display device for image display provided in front of the user's face. The display device, like a liquid crystal display, controls a panel-like display unit, a light source unit that makes light incident on the display unit, and emitted light that is emitted from the display unit, thereby displaying an image corresponding to the emitted light on the display unit. A drawing control means for drawing is included. Since the light source unit is configured to emit near infrared light, the near infrared light can be incident on the display unit from the light source unit. Since the near-infrared light cannot be projected on the user's face simply by the near-infrared light being incident on the display unit, the drawing control means draws the near-infrared light from the display unit while drawing an image on the display unit. Let it emit. Thereby, near infrared light can be uniformly projected on the user's face from the panel-shaped display unit. In addition, since an image is drawn on the display unit, the role of the original display device can be secured. Furthermore, since the near-infrared light can be projected using an existing display device, the system configuration can be simplified as compared with the case where a surface light source only for projecting the near-infrared light is provided on the user's face.

In the present invention, a filter that allows light of a predetermined wavelength to pass through is provided for each pixel in the display unit.
The filter is configured to pass near infrared light,
The drawing control means draws an image of a color corresponding to the light of the predetermined wavelength, and emits near infrared light from pixels constituting the image.

  According to this, in the display device, a filter is provided for each pixel in the display unit, and an image having a color corresponding to the wavelength of light that has passed through the filter (for example, a single-color image composed of one color or a plurality of colors). A color image composed of: In this case, the problem is how to emit near-infrared light from the light source unit from the display unit, but in the present invention, in addition to light for image drawing, near-infrared light is also emitted. It is configured to pass through. Therefore, the drawing control means can emit near-infrared light from the pixels constituting the image while drawing a monochrome image or a color image. Thus, the filter (allowing near infrared light to pass through) and the drawing control means (controlling so as to emit the near infrared light) can be changed only by slightly changing the configuration of the existing display device. Only near infrared light can be projected onto the user's face from an existing display device.

In the present invention, the filter is an RGB color filter, and at least one of the RGB color filters is configured to pass near-infrared light,
The drawing control means draws a color image on the display unit by controlling the amount of light passing through each color filter constituting the RGB color filter, and passes the near-infrared light. Near infrared light is emitted while emitting visible light of a color determined by the color filter through the filter.

  According to this, an RGB color filter is arranged for each pixel in the display unit, and a color image is displayed by controlling the amount of light passing through the color filter. In addition, since at least one of the RGB color filters is configured to allow near-infrared light to pass through, the drawing control means passes the near-red light through the color filter capable of passing near-infrared light. External light can be emitted. At that time, visible light that can pass through the color filter is also emitted, so that an image of a color corresponding to the visible light can be drawn on the display unit. In addition, it is not necessary to provide a dedicated near-infrared light filter that transmits near-infrared light, and the occupied area of the RGB color filter can be maintained, so that the color purity of the color image can be maintained. Note that the color filter that allows near-infrared light to pass through may be any color filter of RGB color filters. That is, a red (R) color filter is configured as an R + IR (near infrared light) color filter, a green (G) color filter is configured as a G + IR color filter, and a blue (B) color filter is configured. Or a B + IR color filter.

In the present invention, the filter is an RGB color filter and a near-infrared light filter that transmits near-infrared light,
The drawing control means draws a color image on the display unit by controlling the amount of light that passes through the color filters of each color constituting the RGB color filter, and passes through the near-infrared light filter. It is characterized by emitting near infrared light.

  Thus, in addition to the RGB color filters for drawing a color image, a dedicated near-infrared light filter that transmits near-infrared light for emitting near-infrared light is provided on the display unit of the display device. It may be provided. Accordingly, it is possible to easily emit near-infrared light from the display unit to the drawing control unit regardless of the contents of the image to be drawn.

  The light source unit according to the present invention includes a visible light source that emits visible light for image drawing and a near-infrared light source that emits near-infrared light. Thereby, the near infrared light from the near infrared light source can be emitted from the display unit while the image is drawn on the display unit by the visible light from the visible light source.

Further, in the present invention, provided with a light projection amount setting means for setting a target light projection amount of near-infrared light irradiated on the user's face,
The drawing control unit causes the display unit to emit near-infrared light having the target light projection amount set by the light projection amount setting unit.

  According to this, since the light projection amount setting unit sets the target light projection amount and the drawing control unit emits the near infrared light of the target light projection amount, the light projection amount of the near infrared light projected onto the user's face is set. It can be changed appropriately.

The display device in the present invention is a liquid crystal display device,
The drawing control unit emits near-infrared light having the target light projection amount from the display unit by controlling a direction of liquid crystal in the liquid crystal display device.

  According to this, since the color and the amount of light emitted from the display unit are adjusted by controlling the direction of the liquid crystal in the liquid crystal display device, the drawing control unit controls the direction of the liquid crystal, Near infrared light having a target light projection amount can be emitted.

  Further, in the present invention, it is provided with light source power control means for controlling the power of the near-infrared light emitted from the light source unit so that the near-infrared light of the target light projection amount is emitted from the display unit. Also good.

  According to this, since the light power from the light source unit can be controlled to brighten or darken the entire display unit, the light source power control means controls the near infrared light power of the light source unit. Thus, near-infrared light having a target light projection amount can be easily emitted from the display unit.

  Further, the light projection amount setting means in the present invention includes a first ambient light determination means for determining ambient brightness by ambient light, and the brightness of the ambient light determined by the first ambient light determination means is bright. The target light output amount is set to be as large as possible.

  In a system that projects near-infrared light onto the user's face, ambient light other than near-infrared light projected from the system is regarded as a disturbance. That is, as the influence of ambient light (disturbance) increases, near-infrared light projection is attenuated. According to the present invention, the first ambient light determination unit determines the ambient brightness due to the ambient light, and the projection light amount setting unit sets the larger target projection light amount as the brightness of the ambient light becomes brighter. Regardless, near-infrared light can be projected optimally.

Further, the display device according to the present invention is configured to project near-infrared light having a light projection amount according to an image drawn on the display unit,
A standard image that is an image to be drawn on the display unit by the drawing control means at each time point is determined,
A light projection amount judging means for judging whether or not a light projection amount of near-infrared light by the standard image at the present time satisfies the target light projection amount;
In the case where the light projection amount determining unit determines that the target light amount is not satisfied, in addition to the standard image, the drawing control unit is a light amount of near infrared light that is insufficient for the target light amount. An auxiliary image corresponding to the insufficient light projection amount is drawn on the display unit.

  According to this, a predetermined standard image such as a vehicle meter image is drawn on the display unit. In this case, since the display device is configured to project near-infrared light with a projection amount corresponding to the image drawn on the display unit, the near-infrared light with a projection amount according to the standard image is projected. Although the light is emitted, the light projection amount may not satisfy the target light projection amount. Therefore, the light projection amount judging means judges whether or not the near infrared light projection amount by the standard image at the present time satisfies the target light projection amount, and if not, the drawing control means adds to the standard image. Thus, an auxiliary image corresponding to the insufficient light projection amount is also drawn on the display unit. This makes it possible to project near-infrared light having a target light projection amount while drawing a standard image.

Further, the display device according to the present invention is configured to project near-infrared light having a light projection amount according to the color of the image drawn on the display unit,
The drawing control means draws a background color image that is a background color image in a background area other than the area where the standard image is drawn as the auxiliary image, and near-infrared so as to compensate for the insufficient light projection amount. The background color image having a mixed color is drawn on condition that light is allowed to pass.

  According to this, a background color image is drawn as an auxiliary image. In this case, since the display device is configured to project near-infrared light having a light projection amount according to the color of the image drawn on the display unit, in addition to the near-infrared light associated with the standard image, the background It is also possible to project near-infrared light having a light projection amount corresponding to the color image. The background color is adjusted to a mixed color on condition that near-infrared light is allowed to pass so as to compensate for the insufficient light quantity, so that the target light quantity can be easily adjusted while ensuring the visibility of the standard image. Can emit near infrared light.

  Further, the drawing control means in the present invention is characterized in that when changing the hue of the background color image, the hue is gradually changed to a target hue. As a result, it is possible to suppress a situation in which the visual recognition of the standard image is hindered due to an abrupt change in the background color.

Further, in the present invention, a time measuring means for measuring an elapsed time after the hue of the background color image is changed,
Elapsed time determination means for determining whether or not the elapsed time measured by the time measuring means is a predetermined time or more,
The drawing control unit does not change the hue of the background color image until the elapsed time determination unit determines that the elapsed time is equal to or longer than the predetermined time.

  According to this, since the hue of the background color is not changed until a predetermined time has elapsed since the previous change in the hue of the background color, it is possible to prevent inconvenience due to frequent changes in the hue of the background color.

Further, in the present invention, a projection pattern that indicates an emission distribution of near-infrared light between each region in the display unit is determined, and a plurality of predetermined regions in the display unit are determined. A light projecting pattern determining means for determining the light projecting pattern having a uniform distribution;
The drawing control unit emits near-infrared light from the display unit according to the projection pattern determined by the projection pattern determination unit.

  According to this, since the near infrared light is emitted from the display unit with a light projection pattern having a uniform distribution among a plurality of predetermined regions in the display unit, the near infrared light is more evenly distributed to the user's face. Can project light. Note that the uniformly distributed light projecting pattern here refers not only to a completely uniform distribution among a plurality of areas of the display unit, but also includes a case where there is a slight difference in the amount of light emitted from each area. It is.

  Further, the light projection pattern determining means according to the present invention is a second ambient light determination that determines a bias in brightness due to ambient light in a light projection region that is a region where near infrared light is projected from the display device. A relatively dark area in the light projection area instead of the light projection pattern having the uniform distribution when the second ambient light determination means determines that there is a deviation in brightness. The light projection pattern is determined so that the amount of near infrared light to be emitted increases.

  There are cases where ambient light shines into the floodlight system from a specific direction, such as a western day in the evening. In this case, the brightness is biased within the light projection area. According to the present invention, near-infrared light is emitted with a light-projecting pattern in which the amount of near-infrared light increases in a relatively dark area in the light-projected area, instead of the light-projected pattern having a uniform distribution. Therefore, it is possible to balance the light in the light projecting area.

  In addition, the display device according to the present invention is a display device that is provided in front of a driver's seat of a vehicle and displays a meter image that displays measurement values related to the vehicle.

  Since a display device for displaying a meter image in a vehicle is provided near the driver's face in front of the driver's seat, when the present invention is applied to the display device, relatively strong near infrared light is projected onto the driver's face. it can. Further, the driver can check the measured value of the meter displayed on the display device while the near infrared light is projected.

  A face photographing system according to the present invention includes the light projecting system according to the present invention and photographing means for photographing a region including the user's face. According to this, since the user's face in which near infrared light is uniformly projected can be photographed, a photographed image in which the user's face is clearly reflected can be obtained.

1 is a block diagram of a schematic configuration of a driver monitor system 1. FIG. It is the figure which illustrated the display state of the display part 11 (display surface 110). 3 is a diagram illustrating a detailed configuration of a display unit 11. FIG. 3 is a cross-sectional view of a light source unit 12. FIG. FIG. 6 is a diagram illustrating a color filter 116. It is the figure which showed the characteristic of each color filter 116a-116c. 4 is a flowchart of near-infrared light projection processing for projecting near-infrared light from the liquid crystal display device 10. It is a detailed flowchart for the process of S15 of FIG. It is a figure explaining that the background color of the display surface 110 changes according to the light projection conditions of near infrared light. It is a figure explaining the example which projects near-infrared light through a half mirror. It is a figure explaining the illumination intensity nonuniformity in the conventional projector.

  Hereinafter, embodiments of a light projecting system and a face photographing system according to the present invention will be described with reference to the drawings. In this embodiment, an example in which the light projecting system and the face photographing system of the present invention are applied to a driver monitor system that monitors a driver of a vehicle will be described. FIG. 1 shows a block diagram of a schematic configuration of a driver monitor system 1 of the present embodiment. The driver monitor system 1 is configured using an existing liquid crystal display device 10 provided in a vehicle. The liquid crystal display device 10 is a display device that is provided in an instrument panel section (not shown) in front of the driver's seat and displays a pointer or the like indicating a measured value such as a vehicle speed or an engine speed as a meter image.

  Here, FIG. 2 is a diagram illustrating a display state of the panel-like display unit 11 (see FIG. 1) of the liquid crystal display device 10. As shown in FIG. 2, the display surface 110 of the display unit 11 has an elongated shape in the vehicle width direction when viewed from the front. When the area of the display surface 110 is divided into four parts on the left and right (in FIG. 2, for convenience of explanation, the boundary of each area is indicated by a dotted line), in FIG. 2, various images are displayed in the middle two areas 110b and 110c. An example in which is displayed. Specifically, a left side area 110b (hereinafter referred to as a first meter display area) of the areas 110b and 110c includes a meter image 31 indicating engine speed, a meter image 35 indicating engine water temperature, and an average. A meter image 33 instructing fuel consumption is displayed. In the area 110c on the right side (hereinafter referred to as a second meter display area), a meter image 32 indicating the vehicle speed with a pointer, a vehicle speed image 34 indicating a numerical value of the vehicle speed, and a meter image 36 indicating the fuel remaining amount are displayed. ing. Further, a shift position is shown in a region between the meter image 31 of the engine speed and the meter image 32 of the vehicle speed (a region near the boundary between the first meter display region 110b and the second meter display region 110c). A road information image 38 showing road information such as the distance to the shift position image 37 and the next right / left turn point is displayed.

  In addition, in each meter display area 110b, 110c, images other than those illustrated in FIG. 2 can be displayed. For example, a warning image in a case where a captured image by a night view camera is displayed or a rear-end vehicle is likely to collide. Various alarms are displayed. That is, the contents (display contents) of the images displayed in the meter display areas 110b and 110c change from moment to moment. In the following, the images drawn in the meter display areas 110b and 110c are also referred to as “standard images”.

  2 shows an example in which nothing is displayed in the leftmost region 110a and the rightmost region 110d among the four divided regions 110a to 110d of the display surface 110. In the present embodiment, the shades of these regions 110a and 110d are changed according to the target light projection amount of near-infrared light projected onto the driver's face. That is, these areas 110a and 110d are areas for adjusting the amount of light emitted by near-infrared light by changing the hue.

  The liquid crystal display device 10 has the same structure as a general liquid crystal display device. Specifically, as shown in FIG. 1, a panel-shaped display unit 11 and a light source unit 12 serving as a backlight of the display unit 11. The drawing controller 13 that controls the orientation of the liquid crystal molecules in the display unit 11 to draw an image on the display unit 11, the display content controller 14 that determines the display content to be drawn by the drawing controller 13, and the brightness of the display unit 11 A brightness adjustment unit 15 is provided for adjusting the brightness. FIG. 3 is a diagram showing a detailed configuration of the display unit 11, and specifically shows an exploded perspective view of each configuration of the display unit 11. FIG. 3 also shows the light source unit 12. FIG. 4 shows a cross-sectional view of the light source unit 12. Hereinafter, the display unit 11 and the light source unit 12 will be described in detail with reference to FIGS. 3 and 4.

  The light source unit 12 is a backlight that supplies (incides) light to the display unit 11 from the back side, and as shown in FIGS. 3 and 4, in this embodiment, the edge light that enters light from the edge side of the display unit 11. It is considered as the backlight of the mold. The light source unit 12 mainly includes a light source unit 121 and a light guide plate 122. The light source 121 includes a red LED 121a that emits red light, a green LED 121b that emits green light, a blue LED 121c that emits blue light, and near-red light that emits near-infrared light (light having a wavelength of 700 nm to 1000 nm). It is comprised from outside LED121d (refer FIG. 4). That is, the light source unit 121 emits near-infrared light that projects near the driver's face in addition to the RGB LEDs 121 a to 121 c as visible light sources for drawing an image on the display unit 11. 121d.

  In the present embodiment, the light source unit 121 emits light as white light in which the light of each RGB color is mixed by causing the LEDs 121a to 121c to simultaneously emit light of each RGB color with the same intensity. . Moreover, it is comprised so that near infrared light may be light-emitted from near infrared LED121d simultaneously with light emission of white light. Therefore, the light source unit 121 emits light in the form of white light including near-infrared light which is invisible light. The light source unit 121 may be configured to be capable of adjusting the intensity (light amount) of light emitted from each of the LEDs 121a to 121c. In this case, the light of the color according to each light quantity from each LED121a-121c will be light-emitted. In view of the fact that the wavelength of near-infrared light and the wavelength of red light are relatively close, instead of the near-infrared LED 121d, a red LED that emits red light in a form in which near-infrared light is superimposed is used. It may be adopted. On the other hand, some near-infrared light LEDs also appear to contain a visible light component. Depending on the intensity of the near-infrared light LED, the red light component may be subtracted from the red LED intensity to change the color of the visible light component. The purity (white appears white) can be increased. Further, the light source of the light source unit 121 is not limited to the LED as long as it is a light source capable of emitting near-infrared light, and other types of light sources such as a halogen light source and an EL (Electro_luminescence) may be employed.

  Light L3 from the light source unit 121 is incident on the light guide plate 122. The light guide plate 122 is a plate-like member that is provided immediately below the back surface of the display unit 11 and that matches the surface shape of the display unit 11. The light guide plate 122 is formed of a material having a light guide property such as acrylic, and propagates (guides) the incident light L <b> 3 throughout the light guide plate 122. As shown in FIG. 4, a cover 123 for allowing the light L <b> 3 from the light source unit 121 to efficiently enter the light guide plate 122 is provided around the light source unit 121. A plurality of reflective dots 124 are formed on the bottom surface 122a of the light guide plate 122 at appropriate intervals. The reflection dots 124 are formed of, for example, white ink, and change the reflection angle of the light L3 propagating through the light guide plate 122 at the bottom surface 122a to reflect the light L3 toward the top surface 122b of the light guide plate 122. It is. In this way, the light L3 from the light source unit 121 is propagated into the light guide plate 122 and is emitted from the entire upper surface 122b of the light guide plate 122 by being reflected by each reflective dot 124. Since the light from the light source unit 121 includes near infrared light as described above, the light guide plate 122 has a structure that can also guide near infrared light.

  Since the light guide plate 122 is a plate-like member that matches the surface shape of the display unit 11, the light from the light source unit 121 is incident on the entire surface of the display unit 11. As described above, the light source unit 12 is an edge light type in which light is incident on the display unit 11 via the light guide plate 122, but a direct light source unit in which a light source unit is provided directly below the back surface of the display unit 11. May be adopted.

  The display unit 11 has the same structure as a general liquid crystal display unit. Specifically, as shown in FIG. 3, the first polarizing plate 111, the array substrate 112, the liquid crystal layer 113, and the color are sequentially arranged from the back side. The filter substrate 114 and the second polarizing plate 115 are stacked. Further, on the array substrate 112, a sub-pixel electrode 112a and an alignment film 112b for applying a voltage to the sub-pixel corresponding to each color of RGB in the pixel are formed. On the color filter substrate 114, a common electrode 114a and an alignment film 114b for applying a voltage in common to each pixel are formed. The alignment films 112b and 114b align liquid crystal molecules of the liquid crystal in a specific direction in a state where no voltage is applied to the liquid crystal layer 113 made of liquid crystal such as nematic liquid crystal. The polarizing plates 111 and 115 allow only light (polarized light) having a specific amplitude component among the light from the light source unit 12 to pass therethrough. Depending on the arrangement direction of the polarizing plates 111 and 115, a normally white mode for bright display (white display) or a normally black mode for dark display (black display) may be selected when no voltage is applied. To do. The liquid crystal layer 113 is made of liquid crystal that hardly absorbs near infrared light from the light source unit 12.

  On the color filter substrate 114, in addition to the common electrode 114a and the alignment film 114b, RGB color filters corresponding to the respective pixels are formed. Here, FIG. 5 shows a state in which the color filter 116 is formed on the color filter substrate 114, and more specifically shows various modes of arrangement examples of the color filter 116. FIG. 5A shows an example in which a red color filter 116a that passes red light, a green color filter 116b that passes green light, and a blue color filter 116c that passes blue light are arranged in stripes. ing. FIG. 5B shows an example in which the color filters 116a to 116c for each color are arranged vertically and horizontally. FIG. 5C shows an example in which the color filters 116a to 116c for each color are arranged in a triangle shape (delta shape) with the adjacent color filters 116a to 116c. Thus, also in the present invention, the general color filter arrangement shown in FIG. 5 can be adopted.

  Note that one pixel is composed of a pair of adjacent color filters 116a to 116c. In addition, among the one pixel, the areas of the color filters 116a to 116c are sub-pixels. The sub pixel electrode 112a in FIG. 3 is formed for each sub pixel.

  FIG. 6 shows the characteristics of the color filters 116a to 116c. Specifically, the horizontal axis represents the light wavelength, and the vertical axis represents the intensity (transmittance) of the light passing through the color filters 116a to 116c. In the graph, a line 131a indicating the characteristics of the red color filter 116a, a line 131b indicating the characteristics of the green color filter 116b, and a line 131c indicating the characteristics of the blue color filter 116c are illustrated. FIG. 6 also shows a near-infrared light spectrum 141. As indicated by the line 131a to 131c of each filter in FIG. 6, the transmittance of each color filter 116a to 116c is large in the wavelength region of the corresponding color light. Further, as indicated by the line 131a of the red color filter 116a, in the red color filter 116a, in addition to the wavelength range of red light (wavelength of 600 nm to 700 nm), the wavelength range of near infrared light (see spectrum 141) is also included. The light transmittance is increased. That is, the red color filter 116a is configured to allow near infrared light to pass through in addition to red light.

  In the display unit 11 configured as described above, when a voltage is applied between the sub-pixel electrode 112a and the common electrode 114a, the orientation of the liquid crystal molecules of the liquid crystal layer 113 between the electrodes 112a and 114a changes. . Further, the orientation of the liquid crystal molecules at that time is set in accordance with the magnitude of the applied voltage. In this way, the amount of light of each color emitted from each sub-pixel of each pixel is controlled by controlling the sub-pixel electrode 112a to which the voltage is applied and the magnitude of the voltage. As a result, various color images are drawn on the display surface 110 (see FIG. 2) of the display unit 11. Further, the near infrared light included in the light from the light source unit 12 is emitted from the display unit 11 through the red color filter 116a. Therefore, by controlling the voltage applied to the sub-pixel electrode 112a corresponding to the red color filter 116a, the emission position and the amount of near-infrared light emitted from the display unit 11 can be controlled. In addition, since red light is also emitted with the emission of near infrared light, an image (red image) generated by the red light is drawn on the display surface 110 of the display unit 11. It will be.

  In recent years, as described in JP 2010-66751 A, a near-infrared absorption filter that absorbs near-infrared light may be provided in a liquid crystal display device. Such a near-infrared absorption filter is not provided.

  Returning to the description of FIG. 1, the above-described control of the display unit 11 (control of the orientation of liquid crystal molecules) is performed by the drawing control unit 13. That is, the drawing control unit 13 draws various images on the display unit 11 by controlling the electrodes 112a and 114a to which the voltage is applied and the magnitude of the voltage. Further, the drawing control unit 13 controls the display unit 11 so that the brightness of the image drawn on the display unit 11 is changed based on the signal from the brightness adjustment unit 15. For example, when the display unit 11 is brightened, the drawing control unit 13 adjusts the orientation of the liquid crystal molecules in the liquid crystal layer 113 in the direction in which the amount of light emitted from each pixel of the display unit 11 is increased. The brightness adjustment unit 15 is, for example, a headlight on / off switch or a setting switch that allows the user to set the brightness. For example, when the headlight is turned on at night, the drawing control unit 13 adjusts (decreases) the brightness (luminance) of the meter image to be drawn in order to improve the visibility of the meter image.

  Further, the drawing control unit 13 controls the amount of near-infrared light emitted from the display unit 11 and from which area of the display unit 11 the near-infrared light is emitted to the driver's face. Also do. The process related to the control is also a feature of the present invention, and will be described in detail later.

  The image to be drawn by the drawing control unit 13 is determined by the display content control unit 14. The display content control unit 14 is a part that determines the content (display content) of the image to be drawn by the drawing control unit 13 at each time point (each scene). Specifically, for example, the above-described various meter images (see FIG. 2). In this case, the display content control unit 14 displays the scale along the meter frame in the basic meter image before instructing the measurement value (for example, in the meter image 31 instructing the engine speed in FIG. 2). Image) is stored in advance in a memory (not shown). And the measured value from the sensor (not shown) which measures physical quantities, such as an engine speed, is acquired. And the meter image which reflected the measured value acquired with respect to the basic meter image memorize | stored in memory (indicating the measured value) is produced | generated. Then, the display content control unit 14 transmits information on the generated meter image (including information indicating which region of the display unit 11 is to be drawn) to the drawing control unit 13, and sends the meter to the drawing control unit 13. Draw an image.

  As described above, in addition to the meter image, an image captured by the night view camera and various alarms are drawn on the display unit 11, so that the display content control unit 14 is, for example, a start switch for the night view camera When (not shown) is operated by the user, an image captured by the night view camera is acquired. Then, the display content control unit 14 transmits the captured image to the drawing control unit 13 and causes the display unit 11 to draw the image.

  As described above, the driver monitor system 1 is configured to include the liquid crystal display device 10 that also functions as a projector that projects near-infrared light onto the driver's face, but the original configuration as a driver monitor system is also included. I have. Specifically, as shown in FIG. 1, the driver monitor system 1 includes an imaging unit 21, a camera control unit 22, an image processing unit 23, a state estimation unit 24, an actuation control unit 25, an alert / alarm means 26, An imaging / light projection condition setting unit 27 and a near infrared LED light emission control unit 28 are provided.

  The imaging unit 21 (camera) is configured by an imaging element such as a CCD image sensor or a CMOS image sensor, and images an area in front of the imaging unit 21. The imaging unit 21 is provided at a position where the driver's face can be photographed, specifically, for example, on the upper surface of a steering column (not shown). That is, the imaging unit 21 captures the driver's face. The imaging unit 21 is provided with a visible light cut filter (not shown) that cuts visible light from the outside. Therefore, light other than visible light such as near-infrared light is captured by the imaging unit 21, and as a result, the captured image captured by the imaging unit 21 is a black and white photograph.

  Note that a polarizing plate in a direction different from that of the second polarizing plate 115 of the liquid crystal display device 10 may be provided on the imaging unit 21 side (a lens portion of the imaging unit 21). Near-infrared light from the liquid crystal display device 10 is polarized light having an amplitude component corresponding to the second polarizing plate 115, but by providing a polarizing plate on the imaging unit 21 side, other amplitude components are provided. Can be taken into the imaging unit 21. Therefore, a captured image with a high SN can be obtained. The near-infrared light from the liquid crystal display device 10 is scattered when reflected by the driver, but when the polarized near-infrared light is polarized, for example, when it strikes spectacles, the imaging unit In some cases, head to 21. Therefore, it is effective to provide a polarizing plate also on the imaging unit 21 side.

  Contrary to the concept of the polarizing plate, the imaging unit 21 excludes the light polarized by the second polarizing plate 115 so that the near infrared light from the liquid crystal display device 10 does not directly enter the imaging unit 21. You may make it the structure to do. As a result, it is possible to prevent near-infrared light from the liquid crystal display device 10 from directly entering the imaging unit 21, and it is possible to capture only near-infrared light scattered by hitting the driver into the imaging unit 21. Further, a steering pad (not shown) provided in front of the driver's seat may be formed of a surface material that absorbs near infrared light. Thereby, it is possible to prevent near infrared light from being reflected by the steering pad and taken into the imaging unit 21.

  The camera control unit 22 is a part that controls the operation of the imaging unit 21 such as the gain and shutter time of the imaging unit 21. The camera control unit 22 controls the imaging unit 21 in accordance with conditions (gain, shutter time, etc.) set by an imaging / light projection condition setting unit 27 described later.

  The image processing unit 23 is a part that acquires a captured image captured by the imaging unit 21 via the camera control unit 22 and executes predetermined image processing based on the captured image. Specifically, the image processing unit 23 executes an extraction process for extracting a face area corresponding to the face of the driver included in the captured image. As the extraction processing, for example, the characteristics (shape information and pixel value information) of each facial part such as mouth, eyes, and nose that compose the face, which are stored in advance in a memory (not shown), and each region in the captured image A process of extracting a face region by comparing with the above feature is included. Since the process of extracting the face area is well known, detailed description is omitted here. Further, the image processing unit 23 performs various image processes such as calculating pixel value information and contrast information in the captured image, in addition to extracting the face area.

  The state estimation unit 24 is a part that estimates the state of the driver based on the recognition result of the driver's face by the image processing unit 23. Specifically, the state estimation unit 24 estimates, for example, the driver's face orientation or the eye opening degree. As a method for estimating the driver's face orientation, for example, there is a method for estimating based on the symmetry of the facial part in the extracted face region. Moreover, as a method of estimating the opening degree of the eye, there is a method of estimating based on the distance between the upper and lower eyelids of the eye region corresponding to the eye.

  The actuation control unit 25 is a part that gives a warning or the like as necessary based on the estimation result by the state estimation unit 24, in other words, a part that controls the operation of the alert / alarm means 26 described later. For example, the actuation control unit 25 determines that the driver is looking aside based on the driver's face orientation or that the driver is dozing based on the eye opening of the driver. If so, the alert / alarm means 26 is driven to alert the driver or issue an alarm. The alert / alarm means 26 is, for example, a buzzer (speaker) or a vibration device that vibrates the driver's seat. The actuation control unit 25 may instruct the display content control unit 14 to display a warning message on the liquid crystal display device 10 when giving a warning.

  The imaging / light-projecting condition setting unit 27 determines the imaging conditions (gain, shutter time, etc.) by the imaging unit 21 and the liquid crystal display device 10 so that the driver's face can be optimally recognized based on the processing result by the image processing unit 23. This is a part for setting near-infrared light projection conditions (light projection amount, light projection balance, etc.). Specifically, the imaging / light projection condition setting unit 27, for example, increases the gain or lengthens the exposure time when the pixel value of the captured image by the imaging unit 21 is low. Set a condition to increase. Furthermore, the imaging / light projection condition setting unit 27 also performs processing for optimizing the light projection balance of near-infrared light from the liquid crystal display device 10. Specifically, the brightness deviation of the projection area where the near-infrared light by ambient ambient light (sunlight or the like) is projected is determined, and the determination result will be described later. Send to. Details of the processing at that time will be described later.

  The near-infrared LED light emission control unit 28 emits light from the display unit 11 so as to satisfy the conditions set by the imaging / light-projecting condition setting unit 27 (particularly, conditions regarding light projection of near-infrared light). This is the part that sets the infrared light conditions. Specifically, the near-infrared LED light emission control unit 28 determines which region of the display unit 11 from which region based on the setting conditions and the determination result (the determination result of the brightness bias) by the imaging / light projection condition setting unit 27. A certain amount of near-infrared light is emitted, that is, a light amount (power) of the near-infrared light to be emitted and a position (light projection pattern) to be emitted are set. Details of the processing for setting the conditions will be described later.

  Each processing unit 13, 14, 22 to 28 described above includes a CPU, a ROM, a RAM, and the like. Each CPU executes processes according to a program stored in advance in the ROM, so that each operation described above is performed.

  As shown in FIG. 1, the driver monitor system 1 includes a dedicated projector 29 (auxiliary projector) composed of near-infrared LEDs that emit near-infrared light separately from the liquid crystal display device 10. Also good. The auxiliary projector 29 projects the near-infrared light supplementarily when the target light projection amount of the near-infrared light cannot be secured by the liquid crystal display device 10 alone for the convenience of the image drawn on the display unit 11. .

  Next, a near-infrared light projecting process that is performed by the driver monitor system 1 and projects near-infrared light from the liquid crystal display device 10 onto the driver's face will be described. FIG. 7 shows a flowchart of the near-infrared light projection process. The process of the flowchart of FIG. 7 is started at the same time as the engine start of the vehicle, for example, and then repeatedly executed until the engine is stopped. Note that the imaging conditions (gain, shutter time, etc.) of the imaging unit 21 at the start of processing and the near-infrared light projection conditions (e.g., light projection amount, light projection balance) by the liquid crystal display device 10 are determined in advance. Used.

  First, based on an instruction from the camera control unit 22, the image of the driver's face is imaged by the imaging unit 21 (S11). Next, the image processing unit 23 calculates information on the brightness of the captured image such as a pixel value and contrast (hereinafter referred to as brightness information) based on the captured image captured in S11 (S12). Next, based on the brightness information calculated in S12, the imaging / light projection condition setting unit 27 determines whether the captured image is appropriate as an image for recognizing the driver's face (S13). Specifically, it is determined whether or not the brightness information of the captured image is included in a predetermined appropriate range (S13). When the brightness information is included in the appropriate range (S13: Yes), it is determined that the captured image is appropriate, and the process returns to S11. In this case, the current light projection condition is maintained and the next imaging is performed (S11).

  In S13, when the brightness information of the captured image is not included in the appropriate range (S13: No), the captured image is not appropriate and the process proceeds to S14. In S14, the near-infrared LED light emission control unit 28 calculates a near-infrared light projection amount (target light projection amount) at which the captured image is appropriate (S14). Specifically, for example, information (hereinafter referred to as “projected light amount information”) indicating how much the projected light amount is changed for each piece of brightness information is appropriate is stored in advance in the memory. In the driver monitor system 1, the ambient light other than the projected near-infrared light is regarded as disturbance (noise). In other words, the brighter the surrounding brightness (ambient light), the more the influence of the projected near infrared light is diminished. Therefore, for example, the light projection amount information is information in which the target light projection amount increases as the brightness indicated by the brightness information increases, for example. In S14, the change amount of the light projection amount corresponding to the current brightness information (brightness information calculated in S12) is read from the light projection amount information (S14). Then, the next target light projection amount is calculated by adding the read change amount to the current light projection amount (S14). Further, since the near-infrared light projecting condition also varies depending on the image capturing condition (gain, shutter time, etc.) of the image capturing unit 21, in S14, the target light projection amount is appropriately set according to the image capturing condition of the image capturing unit 21. It is corrected. Note that the processing of S14 may be executed by the imaging / light projection condition setting unit 27.

  In S14, the example in which the target light projection amount in consideration of the brightness due to the ambient light is calculated based on the photographed image has been described, but the headlight on / off signal from the brightness adjustment unit 15 (see FIG. 1) is also considered. Then, the target light projection amount may be calculated. Specifically, when the headlight is on, the surroundings are dark, such as at night. In this case, it is necessary to darken the meter illumination so that it does not become dazzling, so compared to when the headlight is off. And a small target light projection amount (for example, the target light projection amount is reduced by a predetermined ratio) is calculated. However, near-infrared light that is invisible light may be controlled to be relatively large.

  Next, a light projection pattern indicating from which position (region) of the display unit 11 the near infrared light is emitted is calculated (S15). Here, FIG. 8 shows a detailed flowchart of the processing of S15. First, the imaging / light projection condition setting unit 27 determines the brightness bias due to the ambient light within the light projection region of the near infrared light projected from the display unit 11 (S151). Specifically, the bias of the pixel value between the areas in the captured image is calculated as the brightness bias due to the ambient light (S151). Here, as the bias of the pixel value, when the face area of the photographed image is equally divided into left and right, the pixel value C1 of the left area and the pixel value C2 of the right area are compared (S151). For example, an average value or an integrated value of the pixel values of each pixel is used as the pixel values C1 and C2 of each region. For example, the pixel value C1 in the left region and the pixel value C2 in the right region match (C1 = C2, but there is a match with a certain difference ΔC even if they do not exactly match, that is, C1−C2 <ΔC). When it is, it is determined that there is no bias in brightness due to ambient light (S151). On the other hand, when the pixel value C1 in the left area of the photographed image does not match the pixel value C2 in the right area, the ratio D1 (= C1) of the pixel value C1 to the entire pixel value (C1 + C2) / (C1 + C2)) and the ratio D2 (= C2 / (C1 + C2)) of the pixel value C2 are determined (calculated) as a brightness bias due to ambient light (S151). For example, when the ambient light shines into the vehicle from a specific direction, such as a western day in the evening, the bias corresponding to the direction in which the ambient light shines is determined.

  In S151, the example of determining the deviation between the left and right areas of the face area of the captured image has been described. However, the deviation between any areas such as the upper and lower areas of the face area may be determined. In S151, the example in which the brightness deviation of the light projection area is determined based on the captured image has been described. However, the determination may be performed by an optical sensor that detects light such as a solar radiation sensor.

  Next, the near-infrared LED light emission control unit 28 determines a light projection pattern corresponding to the brightness deviation determined in S151 (S152). Specifically, as the light projection pattern, for example, when the display surface 110 of the display unit 11 is equally divided into left and right, the amount of light emitted from the left area (area 110a + area 110b in FIG. 2) and the right area (FIG. The ratio of the amount of light emitted from the second area 110c + area 110d) is calculated (S152). In other words, the ratio R1 of the amount of light emitted from the left areas 110a and 110b and the ratio R2 of the amount of light emitted from the right areas 110c and 110d with respect to the total light intensity are calculated (S152).

  Specifically, as the ratios R1 and R2, when it is determined that the brightness is not biased in the previous S151 (C1: C2 = 1: 1), the left ratio R1 = 50%, the right The ratio R2 = 50% is calculated (S152). That is, a uniformly distributed light projection pattern is determined (S152). On the other hand, when it is determined that the brightness is biased in the previous S151, the smaller the ratios D1 and D2 of the pixel values C1 and C2 calculated in the previous S151, the larger the ratios R1 and R2 (Conversely, the smaller ratios R1 and R2 are calculated as the ratios D1 and D2 are larger) (S152). As described above, in S152, the light projection pattern is determined so that the light projection amount is relatively increased in the region of the display unit 11 (display surface 110) that projects light in a relatively dark region in the light projection region ( S152). After the process of S152, the process of the flowchart of FIG. 8 is terminated, and the process returns to the process of the flowchart of FIG.

  In FIG. 7, the near infrared light based on a standard image (meter image, image taken by a night view camera, etc.) to be drawn by the drawing control unit 13 in the meter display areas 110 b and 110 c (see FIG. 2) of the display unit 11. The drawing control unit 13 determines whether or not the projected light amount satisfies the target projected light amount calculated in the previous S14 (S16). Specifically, based on how much red image (an image generated with red light) is included in the standard image to be drawn, the amount of light emitted from the near infrared light by the standard image is first determined. Is calculated (S16). Then, the near-infrared light projection amount and the target light projection amount are compared (S16).

  When the light projection amount by the standard image (display content) satisfies the target light projection amount (S16: Yes), the process returns to S11. In this case, the current light projection condition is maintained and the next imaging is performed (S11). On the other hand, when the light projection amount by the standard image (display content) does not satisfy the target light projection amount (S16: No), the process proceeds to S17. In S17, the drawing control unit 13 determines the background colors of the left and right end regions 110a and 110d (background region) of the display unit 11 (display surface 110) so as to satisfy the target light projection amount while maintaining the drawing of the standard image. (S17). Specifically, first, a difference (insufficient light quantity) between the target light quantity and the standard image is calculated (S17). Next, out of the insufficient light quantity, the light quantity assigned to each of the areas 110a and 110d is calculated according to the light projection pattern (ratio R1, R2) determined in the previous S15 (S17). Specifically, “insufficient light quantity × R1” is assigned to the left area 110a, and “insufficient light quantity × R2” is assigned to the right end area 110d. Next, a background color corresponding to the allocated insufficient light quantity is determined for each of the areas 110a and 110d (S17). Specifically, the relationship between the insufficient light intensity and the background color is stored in advance in the memory, and the background color corresponding to the current insufficient light intensity is determined according to the relationship (S17). Since the red light emitted from the display unit 11 increases as the emitted near-infrared light increases, in S17, the background color in which the red purity increases as the insufficient light projection amount increases. .

  Next, the drawing control unit 13 determines whether or not the elapsed time t from the previous change in the background color is equal to or greater than a predetermined threshold Tth (S18). As the elapsed time t, the measurement time in S22 described later is used. The threshold value Tth is set to several seconds, for example. When the elapsed time t is less than the threshold value Tth (S18: No), the process returns to S11. In this case, the current background color is maintained without changing the background color, and the next imaging is performed (S11). The reason for this is that the background color changes every time an image is taken, which leads to driver distraction.

  Thereafter, when the elapsed time t becomes equal to or greater than the threshold value Tth (S18: Yes), the process proceeds to S19. In S19, the drawing control unit 13 determines whether or not the amount of change in the hue of the background color until the background color determined in S17 is equal to or greater than a predetermined threshold Pth (S19). Specifically, first, a difference in hue (a change in hue) between the current background color hue and the target background color (background color determined in S17) is calculated (S19). Then, the hue difference and the threshold value Pth are compared (S19). When the amount of change in hue is less than the threshold value Pth (S19: No), the background colors of the left and right regions 110a and 110d of the display unit 11 are changed to the values (background colors) determined in S17 (S20). ). On the other hand, when the amount of change in hue is equal to or greater than the threshold value Pth (S19: Yes), the background colors of the left and right regions 110a and 110d of the display unit 11 are changed by the hue corresponding to the threshold value Pth in S19. (S21). That is, in this S21, the value (background color) determined in S17 is not changed at a stretch. In this case, in the subsequent processing, the value (background color) finally determined in S17 is set. In this way, since the hue is gradually changed to the target background color, it is possible to prevent the background color from being changed suddenly and to prevent the display unit 11 from displaying a sense of incongruity.

  Here, FIG. 9 is a diagram illustrating the drawing state of the display surface 110 of the display unit 11 in S20 or S21. Specifically, FIG. 9A is a diagram illustrating a state when the surroundings are bright such as daytime, and FIG. 9B is a diagram illustrating a state when the surroundings are dark such as nighttime. FIG. 9C is a diagram showing a state when the ambient brightness is biased by ambient light, such as in the case of a western day in the evening. In FIG. 9, the color intensity of the background color (red image) is represented by the color intensity of the left and right end regions 110a and 110d. Further, FIG. 9 shows an example in which the standard images 31 to 38 that are the same as those in FIG. 2 are drawn in the meter display areas 110b and 11c.

  As shown in FIGS. 9A and 9B, when the surrounding brightness is not biased, background color images of the same color are drawn in the left and right end regions 110a and 110d, respectively. The That is, the background color images 51 and 52 in FIG. 9A are the same, and the background color images 53 and 54 in FIG. 9B are the same. As a result, the near-infrared light projection amounts of the standard images 31 to 38 and the background color images 51 to 54 are changed between the left region (region 110a + region 110b) and the right region (region 110c + region 110d) of the display surface 110. It can be about the same. Therefore, near infrared light can be uniformly projected on the driver's face.

  On the other hand, comparing FIG. 9 (a) and FIG. 9 (b), the background color images 51 and 52 in FIG. 9 (a) whose surroundings are brighter are darker in the background color images 53 and 54 in FIG. 9 (b). The image is darker. That is, the brighter the surroundings, the greater the amount of near infrared light emitted from the display unit 11. As a result, it is possible to suppress the influence of ambient light that is regarded as disturbance. FIGS. 9A and 9B correspond to the case where it is determined in S15 described above that there is no bias in brightness.

  Further, as shown in FIG. 9C, when the surrounding brightness is uneven, the background color image 55 in the left end area 110a and the background color image 56 in the right end area 110d are different from each other. It is considered to be a color image. In the example of FIG. 9C, the background color image 55 in the left end area 110a is darker than the background color image 56 in the right end area 110d. That is, in the example of FIG. 9C, the light projection amount emitted from the left end region 110a is larger than the light emission amount emitted from the right end region 110d. This assumes a state in which ambient light (sunlight) is incident from the right end region 110d side, and considers the uneven brightness. This makes it possible to uniformly project near-infrared light even when ambient light is incident from a specific direction. The case of FIG. 9C corresponds to the case where it is determined in S15 described above that the brightness is uneven.

  Returning to the description of FIG. 7, after the process of S20 or S21, measurement of the elapsed time t from the current background color change is started (S22). The measurement is performed by, for example, the drawing control unit 13. In this case, the drawing control unit 13 includes a timer (not shown). Thereafter, the process returns to S11, and the next imaging is performed with the background color after the change, that is, with the near-infrared light of the target light projection amount being projected in a well-balanced manner (S11).

  As described above, in the present embodiment, the background color is adjusted according to the target light projection amount, so that near infrared light with the target light projection amount can be projected onto the driver's face. Further, when the brightness is not biased by the ambient light, the near-infrared light is uniformly emitted from the display unit 11, so that the near-infrared light can be uniformly projected onto the driver's face. Further, when the brightness is biased by the ambient light, the emission balance of near-infrared light is changed according to the bias, so that the influence of the bias can be suppressed. Further, since a normal standard image (meter image or the like) is displayed on the liquid crystal display device 10, the driver can grasp information such as the vehicle speed and the engine speed as usual.

  The light projecting system and the face photographing system of the present invention are not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the claims. For example, in the above-described embodiment, an example in which an RGB light source and a near-infrared light source for drawing an image are provided in the same place has been described. However, as illustrated in FIG. 70 may be provided at a different location from the RGB light source 71 and reflected by the meter glass 62 of the meter 60 to project near infrared light. Specifically, a near infrared light source 70 is provided on a hood 61 of a meter 60 installed horizontally. The meter glass 62 is provided obliquely to the near-infrared light source 70 and is a half mirror. The RGB light source 71 for drawing an image such as a meter image is provided inside the meter glass 62 as usual. The light L4 from the near-infrared light source 70 travels toward the half mirror meter glass 62 and is reflected by the meter glass 62. The reflected light L5 is projected onto the driver's face. The light L6 from the RGB light source 71 passes through the half mirror meter glass 62 as image light indicating an image. Accordingly, it is possible to easily adjust the light projection amount of the near infrared light regardless of the content of the image displayed on the display device. Moreover, since the near infrared light can be projected from the display surface (meter glass 62) of the display device as in the above embodiment, the near infrared light can be uniformly projected onto the driver's face.

  Moreover, although the said embodiment demonstrated the example which divided the display surface 110 of the display part 11 into right and left, you may divide | segment the display surface 110 how. If the number of divisions of the display surface 110 is increased, the near-infrared light projection can be controlled more finely. In the above embodiment, an example in which a standard image such as a meter image is drawn in the two middle regions 110b and 110c of the display surface 110 has been described. However, the standard image is drawn in the left and right end regions 110a and 110d. May be. Also, the area where the standard image is drawn and the area where the auxiliary image (background color image) is drawn do not have to be clearly divided, and the standard image and auxiliary image are mixed and drawn in the same area. May be.

  In the above-described embodiment, an example of a background color image has been described as an auxiliary image corresponding to the insufficient light projection amount. However, the insufficient light projection amount may be supplemented with another image. Examples of other images include simple graphic images such as circles, triangles, and squares, illustration images, and message images. Moreover, although the said embodiment demonstrated the example which applied this invention to the liquid crystal display device, you may apply this invention to other display apparatuses (plasma display etc.) which have a light source. In addition, when applying this invention to a plasma display, it is necessary to control the production | generation (discharge) of a plasma so that near-infrared light may be light-emitted. In the above-described embodiment, an example in which the present invention is applied to a display device that displays a meter image has been described. For example, the present invention is applied to a display device that displays a navigation screen provided on a control panel between a driver seat and a passenger seat. The invention may be applied. The present invention can also be applied to products in which a camera, lighting, and display are integrated, such as a face authentication system used for entrance / exit management, a TV phone, a TV door phone, and a personal computer.

  In the above embodiment, the red color filter 116a that can also pass near-infrared light is used, and the near-infrared light is emitted from the display unit 11 through the red color filter 116a. Alternatively, a dedicated near-infrared light filter that transmits near-infrared light may be provided. In this case, specifically, a near-infrared light filter is formed for each pixel on the color filter substrate 114 (see FIG. 3). Accordingly, near infrared light can be easily emitted from the display unit 11 regardless of the content of the image to be drawn. However, in this case, the area occupied by the RGB color filters is reduced by the near-infrared light filter, and the color purity of the drawn color image is somewhat sacrificed.

  In the above embodiment, near infrared light is projected through the red color filter 116a. However, near infrared light may be projected from the green color filter 116b and the blue color filter 116c. In this case, it is necessary to configure the color filters 116b and 116c so that near infrared light can pass therethrough. Further, when projecting near-infrared light from the green color filter 116b, since green light is simultaneously transmitted, an image generated by light including green light is drawn on the display unit 11. become. Similarly, when near-infrared light is projected from the blue color filter 116c, an image generated by light including blue light is drawn on the display unit 11.

  In the above embodiment, an example in which the liquid crystal display device is used on the entire surface of the meter has been described. However, a conventional meter (a meter in which a meter frame or scale is printed on the display surface and a pointer is disposed inside the meter frame) ) May be provided with a small liquid crystal display device, and near infrared light may be projected from the small liquid crystal display device. In the above embodiment, an example using a liquid crystal display device that draws a color image in which RGB colors are mixed has been described. However, a liquid crystal display device that draws a single color image (for example, orange single color, white single color, etc.). It can also be applied to. In this case, since a monochrome filter is disposed in each pixel of the display unit of the liquid crystal display device, it is necessary to configure the filter so that near infrared light can also pass therethrough. Thereby, near-infrared light can be projected from each pixel constituting the image while drawing a monochrome image.

  Moreover, in the said embodiment, although the light emission amount of near infrared light was adjusted by controlling the standard image and background color image (auxiliary image) which are drawn on a display part, the near infrared light emitted from a light source unit is adjusted. You may adjust the light quantity of near infrared light by controlling the power of light. For example, if the power of near-infrared light is increased, the amount of near-infrared light passing through the filter can be increased even if the images drawn on the display unit are the same. Therefore, it is possible to easily project near-infrared light having a target light projection amount. In this case, the drawing control unit 13 in FIG. 1 directly controls the power of the light source unit 12 (near infrared LED 121d), or the near infrared LED light emission control unit 28 controls the power of the light source unit 12 (near infrared LED 121d). Control. In this case, the drawing control unit 13 or the near infrared LED light emission control unit 28 corresponds to the “light source power control unit” of the present invention.

  In the above-described embodiment, the insufficient light intensity is compensated by adjusting the hue of the background color image. However, a standard image (such as a meter image) is used simultaneously with or instead of the adjustment of the hue of the background color image. It is also possible to compensate for the insufficient amount of light emitted by adjusting the hue. In this case, the hue of the standard image is adjusted within a color adjustable range where the function as the standard image is not impaired. This makes it easier to project near-infrared light having a target light projection amount.

  In addition, as an original HMI (Human Machine Interface) function of the display device, there is a case where the entire display unit of the display device is required to be changed to a cold color system or a warm color system so as to calm the user's frustration or escape from the state of muzzle. . In this case, although there may be a contradiction with the target light projection amount of near-infrared light, the drawing control unit 13 arbitrates both requests, and determines a cold color system color or a warm color system color to be changed. Specifically, for example, the correspondence relationship between the target light projection amount and the cool color tone or the correspondence relationship between the target light projection amount and the warm color tone is stored in the memory in advance. Then, the hue corresponding to the current target light projection amount is determined from the correspondence stored in the memory. Then, the drawing control unit 13 changes the determined color to a cold color system or a warm color system.

  In the above embodiment, the drawing control unit 13 corresponds to the “drawing control unit” of the present invention. The imaging / light projection condition setting unit 27 and the near-infrared LED light emission control unit 28 that execute the process of S14 in FIG. 7 correspond to the “projection light amount setting unit” and the “first ambient light determination unit” of the present invention. The drawing control unit 13 that executes the process of S16 in FIG. 7 corresponds to the “projection amount determination unit” of the present invention. The drawing control unit 13 that executes the process of S22 of FIG. 7 corresponds to the “timer” of the present invention. The drawing control unit 13 that executes the process of S18 in FIG. 7 corresponds to the “elapsed time determination unit” of the present invention. The imaging / light projection condition setting unit 27 and the near-infrared LED light emission control unit 28 that execute the process of S15 in FIG. 7 correspond to the “light projection pattern determination unit” of the present invention. The imaging / light projection condition setting unit 27 that executes the process of S151 in FIG. 8 corresponds to the “second ambient light determination unit” of the present invention. The imaging unit 21 corresponds to the “imaging unit” of the present invention.

1 Driver monitor system (light projection system, face photography system)
DESCRIPTION OF SYMBOLS 10 Liquid crystal display device 11 Display part 116 Color filter 116a Red color filter 116b Green color filter 116c Blue color filter 12 Light source unit 121 Light source part 121a Red LED
121b Green LED
121c Blue LED
121d near infrared LED
122 Light Guide Plate 13 Drawing Control Unit 14 Display Content Control Unit 15 Brightness Adjustment Unit 21 Imaging Unit 22 Camera Control Unit 23 Image Processing Unit 24 State Estimation Unit 25 Actuation Control Unit 26 Attention / Alarm Unit 27 Imaging / Lighting Condition Setting Unit 28 Near-infrared LED light emission control unit 31-38 Standard image 51-56 Background color image (auxiliary image)

Claims (17)

Controlling the light emitted from the display unit out of the panel-shaped display unit, the light source unit that enters the display unit, and the light from the light source unit, provided in front of the area where the user's face is located A display system including a display control unit that draws an image corresponding to the emitted light on the display unit, and projects a near-infrared light on the user's face,
The light source unit is configured to emit near infrared light,
The drawing control means emits near infrared light from the display unit while drawing an image on the display unit ,
The display device is configured to project near-infrared light having a light projection amount according to an image drawn on the display unit,
A standard image that is an image to be drawn on the display unit by the drawing control means at each time point is determined,
A light projection amount setting means for setting a target light projection amount of near-infrared light irradiated on the user's face;
A light projection amount judging means for judging whether or not a light projection amount of near infrared light by the standard image at the present time satisfies the target light projection amount,
In the case where the light projection amount determining unit determines that the target light amount is not satisfied, in addition to the standard image, the drawing control unit is a light amount of near infrared light that is insufficient for the target light amount. A light projection system , wherein an auxiliary image corresponding to a short light projection amount is drawn on the display unit . Controlling the light emitted from the display unit out of the panel-shaped display unit, the light source unit that enters the display unit, and the light from the light source unit, provided in front of the area where the user's face is located A display system including a display control unit that draws an image corresponding to the emitted light on the display unit, and projects a near-infrared light on the user's face,
The light source unit is configured to emit near infrared light,
The drawing control means emits near infrared light from the display unit while drawing an image on the display unit,
The display device is configured to project near-infrared light having a light projection amount according to an image drawn on the display unit,
A standard image that is an image to be drawn on the display unit by the drawing control means at each time point is determined,
A light projection amount setting means for setting a target light projection amount of near-infrared light irradiated on the user's face;
A light projection amount judging means for judging whether or not the light projection amount of near infrared light by the standard image at the present time satisfies the target light projection amount;
When the projected light amount determining unit determines that the target projected light amount is not satisfied, the insufficient amount adjusting unit adjusts the standard image so that the display unit emits near infrared light that is insufficient for the target projected light amount. A floodlighting system characterized by comprising: Controlling the light emitted from the display unit out of the panel-shaped display unit, the light source unit that enters the display unit, and the light from the light source unit, provided in front of the area where the user's face is located A display system including a display control unit that draws an image corresponding to the emitted light on the display unit, and projects a near-infrared light on the user's face,
The light source unit is configured to emit near infrared light,
Determining a projection pattern indicating an emission distribution of near-infrared light between each region in the display unit, wherein the projection pattern has a uniform distribution among a plurality of predetermined regions in the display unit; A light projection pattern determining means for determining a light pattern;
The drawing control unit causes the near infrared light to be emitted from the display unit according to the projection pattern determined by the projection pattern determination unit while drawing an image on the display unit. . The display unit is provided with a filter that passes light of a predetermined wavelength for each pixel,
The filter is configured to pass near infrared light,
The drawing control unit emits near infrared light from pixels constituting the image while drawing an image of a color corresponding to the light of the predetermined wavelength . The light projecting system according to item 1 . The filter is an RGB color filter, and at least one of the RGB color filters is configured to pass near infrared light,
The drawing control means draws a color image on the display unit by controlling the amount of light passing through each color filter constituting the RGB color filter, and passes the near-infrared light. 5. The light projecting system according to claim 4 , wherein near infrared light is emitted while emitting visible light having a color determined by the color filter through the filter . The filter is an RGB color filter and a near-infrared light filter that transmits near-infrared light,
The drawing control means draws a color image on the display unit by controlling the amount of light that passes through the color filters of each color constituting the RGB color filter, and passes through the near-infrared light filter. The light projection system according to claim 4 , wherein near-infrared light is emitted . The said light source unit contains the visible light source which light-emits the visible light for image drawing, and the near-infrared light source which light-emits near-infrared light, The any one of Claims 1-6 characterized by the above-mentioned. Floodlight system. A light projection amount setting means for setting a target light projection amount of near-infrared light irradiated on the user's face;
The light projection system according to claim 3 , wherein the drawing control unit causes the display unit to emit near-infrared light having the target light projection amount set by the light projection amount setting unit . The display device is a liquid crystal display device;
The said drawing control means makes the near infrared light of the said target light projection amount emit from the said display part by controlling the direction of the liquid crystal in the said liquid crystal display device, The Claim 1, 2, or 8 characterized by the above-mentioned. Floodlight system. Wherein as the near-infrared light of the target projection amount is emitted from the display unit, according to claim 1, characterized in that it comprises a light source power control unit for controlling the power of the near-infrared light emitted from the light source unit The light projection system according to any one of 2, 8, and 9 . The light projection amount setting means includes first ambient light determination means for determining ambient brightness by ambient light, and the target is larger as the brightness of the ambient light determined by the first ambient light determination means is brighter. The light projection system according to any one of claims 1, 2, 8 to 10, wherein a light projection amount is set . The display device is configured to project near-infrared light having a light projection amount according to the color of an image drawn on the display unit,
The drawing control unit is configured to draw a background color image that is a background color image in a background area other than the area where the standard image is drawn as the auxiliary image. The light projection system according to claim 1 , wherein the background color image having a mixed color is drawn on condition that external light is allowed to pass . 13. The light projection system according to claim 12 , wherein when the color of the background color image is changed, the drawing control unit gradually changes the color to a target color . Time measuring means for measuring an elapsed time since the hue of the background color image is changed;
Elapsed time determination means for determining whether or not the elapsed time measured by the time measuring means is a predetermined time or more,
14. The projection according to claim 12 , wherein the drawing control unit does not change a hue of the background color image until the elapsed time is determined by the elapsed time determination unit to be equal to or longer than the predetermined time. Light system. The light projection pattern determining means includes second environmental light determining means for determining a brightness bias due to environmental light in a light projection area that is an area where near infrared light is projected from the display device, If the second ambient light determination means determines that there is a deviation in brightness, the closer the light is emitted in a relatively dark area in the light projection area, instead of the light distribution pattern having the uniform distribution. The light projection system according to claim 3 , wherein the light projection pattern is determined so that the amount of infrared light increases.   The said display apparatus is a display apparatus which displays the meter image which displays the measured value regarding the said vehicle provided in the driver's seat of the vehicle, The any one of Claims 1-15 characterized by the above-mentioned. Floodlight system. The light projecting system according to any one of claims 1 to 16,
A face photographing system comprising: photographing means for photographing an area including the user's face.