Display control method and display control system

Abstract

This invention provides a display control method that can improve the visibility of video content. [Solution] The system comprises a HUD 2 mounted on a vehicle C1 that projects content images onto a projection area 9, which is a specific area of ​​the windshield 8 of the vehicle C1; an imaging device 4 mounted on the vehicle C1 that captures images of the area in front of the vehicle C1; a controlled dimming film 3 positioned in front of the vehicle C1 beyond the in-vehicle side surface of the windshield 8 and adjusting the transmittance of light from the front of the vehicle C1 toward the projection area 9; and a display control device 5 that controls the controlled dimming film 3 based on image data output from the imaging device 4 to improve the visibility of the content images.

Description

Technical Field

[0001] The present disclosure relates to a display control method and a display control system.

Background Art

[0002] Conventionally, an apparatus has been proposed that includes a transparent EL display disposed on a dashboard of a vehicle, a head-up display having a dimming plate disposed closer to a windshield side than the transparent EL display, and a control IC that controls a transmittance of the dimming plate (see, for example, Patent Document 1). In the apparatus described in Patent Document 1, the transmittance of the dimming plate is decreased during daytime to block light from the windshield side to the transparent EL display with the dimming plate, thereby improving visibility of display information of the transparent EL display. During nighttime, the transmittance of the dimming plate is increased to improve visibility of the outside of the vehicle through the dimming plate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the apparatus described in Patent Document 1, for example, when the color of display information of the transparent EL display (hereinafter, also referred to as "content video") is close to the color included in the scenery (foreground) in front of the vehicle, the content video may be buried in the foreground, and the visibility of the content video may be reduced. An object of the present disclosure is to provide a display control method and a display control system capable of improving visibility of content video.

Means for Solving the Problems

[0005] A display control method according to one embodiment of the present disclosure is a display control method for a display control system comprising a head-up display mounted on a vehicle and projecting content images onto a projection area which is a specific area of ​​the vehicle's windshield; an imaging device mounted on the vehicle and capturing images of the area in front of the vehicle; and a dimming unit positioned in front of the vehicle beyond the in-vehicle surface of the windshield and adjusting the transmittance of light from the front of the vehicle toward the projection area, wherein the dimming unit is controlled based on image data output from the imaging device to improve the visibility of the content images.

[0006] Furthermore, a display control device according to one embodiment of the present disclosure includes: a head-up display mounted on a vehicle that projects content images onto a projection area which is a specific area of ​​the vehicle's windshield; an imaging device mounted on the vehicle that captures images of the area in front of the vehicle; a dimming unit positioned in front of the vehicle beyond the in-vehicle surface of the windshield and adjusting the transmittance of light from the front of the vehicle toward the projection area; and a display control device that controls the dimming unit based on image data output from the imaging device to improve the visibility of the content images. [Effects of the Invention]

[0007] This disclosure provides a display control method and a display control system that can improve the visibility of content video. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows the schematic configuration of the information display system according to the embodiment. [Figure 2] This figure shows the windshield, projection area, and content image. [Figure 3] This is a diagram showing the cross-sectional structure of the windshield. [Figure 4] This figure shows the luminance signal and RGB values ​​on any scan line when the foreground viewed through the windshield is a color bar composed of white, yellow, cyan, green, magenta, red, blue, and black color bands. [Figure 5] This figure shows an image of the foreground captured through a windshield. [Figure 6] This figure shows an image of the foreground captured through a windshield in a comparative example. [Figure 7] This is a flowchart showing the overall flow of the display control method of the embodiment. [Figure 8] This figure shows an image of the foreground captured through a windshield. [Figure 9] This figure shows an image of the foreground captured through a windshield in a comparative example. [Figure 10] This diagram shows the windshield, projection area, and content image when the headlights of an oncoming vehicle are bright. [Figure 11] This figure shows the windshield, projection area, and content image when the headlights of an oncoming vehicle are bright, as in the comparative example. [Figure 12] This flowchart shows the overall flow of the display control method for modified examples. [Figure 13] This figure shows the windshield, projection area, and content image. [Figure 14] This figure shows an image of the foreground captured through a windshield in a comparative example. [Modes for carrying out the invention]

[0009] The embodiments of this disclosure will be described below with reference to the drawings. Note that the drawings are schematic and may differ from actual ones. Furthermore, the embodiments of this disclosure shown below are illustrative examples of devices and methods for realizing the technical concept of this disclosure, and the technical concept of this disclosure is not limited to the structure, arrangement, etc., of the components described below. The technical concept of this disclosure can be modified in various ways within the technical scope defined by the claims described in the patent claims.

[0010] (composition) Figure 1 is a diagram showing the schematic configuration of the information display system 1 of this embodiment. In this embodiment, as shown in Figure 1, an example is shown in which the display control method and display control system of the present disclosure are applied to an information display system 1 that is mounted on a vehicle C1 and presents various information such as the status of the vehicle C1, the status of the outside world of the vehicle C1, and the status of the driver assistance system to the occupants of the vehicle C1. The information display system 1 comprises a head-up display (hereinafter also referred to as "HUD") 2, a controllable dimming film 3 (broadly referred to as the "dimming unit"), an imaging device 4, a display control device 5, an illuminance meter 6, and dimming glass 7. HUD2 is a projection-type HUD positioned within the dashboard of vehicle C1, projecting content images 10 onto a specific area (hereinafter also referred to as the "projection area") 9 of the vehicle C1's windshield 8, as shown in Figure 2. The light from the content images 10 is reflected by the projection area 9 and reaches the eyes of the occupant in the driver's seat of vehicle C1. As a result, the occupant in the driver's seat can see a virtual image of the content images 10 floating in front of vehicle C1. Figure 2 shows the windshield 8, the projection area 9, and the content images 10. The projection area 9 is set to overlap with the field of view of the occupant in the driver's seat. Figure 2 illustrates the case where the projection area 9 is set to the lower end of the windshield 8. The content images 10 can include, for example, images showing the status of vehicle C1, the external environment around vehicle C1, and the status of the driver assistance system. The content images 10 also include multiple partial images 10a and 10b with different colors. Figure 2 illustrates a case where partial image 10a is a white image showing the vehicle speed in the lower left corner of the projection area 9, and partial image 10b is a red image showing the lane in which vehicle C1 is traveling (for example, the lane defined by the navigation system) in the center of the projection area 9.

[0011] As shown in FIG. 3, the controllable dimming film 3 is disposed inside a portion of the windshield 8 corresponding to the projection area 9, and is a film that adjusts the transmittance (transparency) of light traveling from the front side of the vehicle C 1 toward the projection area 9 according to the voltage applied from the dimming film control unit 12. As the controllable dimming film 3, for example, a liquid crystal sheet can be adopted which has a high light transmittance (transparency) when no voltage is applied, and whose light transmittance (transparency) becomes lower and approaches black as the applied voltage increases. Note that the controllable dimming film 3 ensures a transmittance that allows the passengers of the vehicle C 1 to see the scenery in front of the vehicle C 1 (hereinafter also referred to as "foreground") through the controllable dimming film 3 even when the light transmittance is at its lowest. FIG. 3 is a diagram showing the cross-sectional configuration of the windshield 8. In FIG. 3, an example is illustrated in which the windshield 8 has a configuration in which the controllable dimming film 3 is disposed between two glass plates 8a and 8b. That is, the controllable dimming film 3 is disposed on the front side of the vehicle C 1 rather than on the inner side surface of the windshield 8. Also, a transparent sheet 8c is disposed in a region between the two glass plates 8a and 8b where the controllable dimming film 3 is not disposed. Note that in FIG. 1, for simplicity of drawing, the controllable dimming film 3 is drawn outside the windshield 8.

[0012] The imaging device 4 is a camera mounted on the vehicle C 1 for imaging the front of the vehicle C 1. For example, it is installed near the head of the driver in the driver's seat (near the rearview mirror) and images the front of the vehicle C 1 through the windshield 8. Thereby, the foreground that the driver in the driver's seat sees through the windshield 8 can be imaged. Also, as the imaging device 4, for example, a video camera that images a video of the foreground can be used. The image data of the imaging device 4 is output to the display control device 5.

[0013] The display control device 5 is a device that controls the controllable dimming film 3 based on the image data. The display control device 5 includes a color analyzer 11 and a dimming film control unit 12. The color analyzer 11 is an analysis device that acquires image data output from the imaging device 4 and analyzes color information from the acquired image data. As the color analyzer 11, for example, a device (colorimeter) that determines the color of the target to be analyzed either in hardware or software using a method such as the CIE1976 L*a*b* color difference formula can be used. Here, for example, if a video camera is used as the imaging device 4, the imaging device 4 outputs a video signal as image data. Also, if the video signal is an NTSC signal, as shown in Figure 4, the video signal consists of a luminance signal and RGB values. Figure 4 is a diagram showing the luminance signal and RGB values ​​on an arbitrary scan line when the foreground viewed through the windshield 8 is a color bar composed of white, yellow, cyan, green, magenta, red, blue, and black color bands. In the left diagram of Figure 4, each color band is the same color at any point in the vertical direction. Therefore, the pattern of the luminance signal and RGB values ​​is the same on any scan line 1 to 525.

[0014] Analysis of color information is performed on a partial captured image 17 that can be seen through a region above the range of the field of view of the driver in the vehicle in the image shown by the image data (hereinafter also referred to as "captured image 13"), as shown in FIG. 5. FIG. 5 is a diagram showing a captured image 13 of the foreground through the windshield 8. In FIG. 5, as an example, the measurement region 14 is set in the region of the windshield 8 that is located above the projection region 9 when looking ahead from the driver's seat of the vehicle C1 in the captured image 13. In the present embodiment, the position of the measurement region 14 is fixed. Also, the measurement region 14 has an area large enough to analyze the color of the body of the oncoming vehicle C2 traveling ahead of the vehicle C1. Here, for example, as a comparative example, when a linear region on the scanning line is used as the measurement region 14, in the region on the first scanning line 15 in FIG. 6, the black of the tire is detected as the color of the oncoming vehicle C2, and in the region on the second scanning line 16 in FIG. 6, the color of the body is detected as the color of the oncoming vehicle C2. That is, when the area of the measurement region 14 is too small, it becomes difficult to appropriately determine the color of the oncoming vehicle C2. The analysis result (color information) of the color analyzer 11 is output to the dimming film control unit 12. FIG. 6 is a diagram showing a captured image 13 of the foreground through the windshield 8 of the comparative example.

[0015] The dimming film control unit 12 is a feedback circuit that acquires color information output from the color analyzer 11 and luminance information output from the illuminance meter 6, and controls the controlled dimming film 3 based on the acquired color information and luminance information to improve the visibility of the content video 10. In controlling the controlled dimming film 3, for example, as shown in Figure 5, it is determined whether the color information of the partial image 17 contains the same or similar color as the color of the partial video 10b. If it is determined that the same or similar color is included, a voltage is applied to the controlled dimming film 3 to reduce the light transmittance of the controlled dimming film 3. This reduces the transparency of the controlled dimming film 3, changes the color tone of the foreground when viewed by the occupants of the vehicle C1 through the projection area 9, suppresses the content video 10 from being buried in the foreground, and improves the visibility of the content video. At that time, the voltage applied to the controlled dimming film 3 is determined by whether the luminance indicated by the luminance information is above a threshold, and if it is determined to be above the threshold, the voltage is made greater than when it is determined to be below the threshold. In other words, the controlled dimming film 3 is controlled using not only color information but also luminance information output from the illuminance meter 6, which detects the intensity of ambient light directed toward the measurement area 13. Alternatively, for example, regardless of the result of the judgment based on the above color information, it may be determined whether the luminance indicated by the luminance information is above a threshold, and if it is determined to be above the threshold, a voltage may be applied to the controlled dimming film 3 to reduce its transmittance. This allows the transparency of the controlled dimming film 3 to be reduced when, for example, the brightness of the windshield 8 increases due to sunlight or the headlights of oncoming vehicles, and the accuracy of the color information analysis decreases.

[0016] The illuminance meter 6 is mounted on the vehicle C1 and is a sensor that detects the intensity of ambient light (brightness of the measurement area 13) directed toward the measurement area 13. Examples of ambient light include sunlight and the headlights of oncoming vehicles. The illuminance meter 6 can be a photodiode or a photoresistor. The detection result (luminance information) of the illuminance meter 6 is output to the dimming film control unit 12.

[0017] The dimmable glass 7 is used in the side and rear windows of vehicle C1, and its transparency changes according to the amount of light (e.g., visible light and ultraviolet light). For example, the dimmable glass 7 can be made of glass coated with a photosensitive material that is highly transparent when the amount of light is low and less transparent when the amount of light is high. This prevents strong light from entering the vehicle through the side and rear windows, prevents color distortion in the content video 10, and improves the visibility of the content video 10. It also improves the visibility of other image display devices in vehicle C1, such as the meter and center display.

[0018] (operation) Next, we will explain the process for changing the transmittance of the controlled dimming film 3. Figure 7 is a flowchart showing the overall flow of the display control method in this embodiment. First, the imaging device 4 captures an image of the area in front of the vehicle C1 and generates image data (S101 in Figure 7). Next, the color analyzer 11 acquires the generated image data and analyzes the color information from the acquired image data (S102 in Figure 7). Simultaneously with the generation of image data and analysis of color information, the illuminance meter 6 detects the intensity (brightness; luminance information) of ambient light directed toward the measurement area 13 (S103 in Figure 7). Subsequently, the dimming film control unit 12 controls the controlled dimming film 3 based on the color information output from the color analyzer 11 and the luminance information output from the illuminance meter 6 (S104-S106 in Figure 7). In other words, it controls the controlled dimming film 3 based on the image data. For example, it determines whether the color information of the partial image 17 contains a color that is the same as or similar to the color of the partial image 10b (for example, red) (S104 in Figure 7). Here, let's assume that, as shown in Figure 5, only the road is visible through the measurement area 14. Then, it is determined that the color information of the partial image 17 does not contain any colors that are the same as or similar to the colors of the partial image 10b (S104 "No" in Figure 7), and no voltage is applied to the controlled dimming film 3 (S105 in Figure 7). As a result, the controlled dimming film 3 can be kept transparent, and the color tone of the foreground when viewed by the occupants of the vehicle C1 through the projection area 9 can be maintained.

[0019] As the above flow S101 to S105 is repeated, vehicle C1 approaches vehicle C2 (a vehicle whose body color is the same as the color of partial image 10b), as shown in Figure 6, and vehicle C2 overlaps the measurement area 14. Then, it is determined that the color information of the partial image 17 contains a color that is the same as or similar to the color of partial image 10b (S104 "Yes" in Figure 7), and a voltage is applied to the dimmable film 3 (S106 in Figure 7). In other words, the dimmable film 3 is controlled so that the visibility of the content image 10 is improved. This reduces the light transmittance (transparency) of the dimmable film 3, changes the color tone of the foreground when viewed by the occupants of vehicle C1 through the projection area 9, and prevents partial image 10b (content image 10) from being buried in the foreground. Regardless of the result of the determination based on the above color information, if the brightness indicated by the brightness information is above the threshold, a voltage is applied to the dimmable film 3. Subsequently, if the vehicle C2 and vehicle C1 approach each other, as shown in Figure 8, the image of the vehicle C2 will occupy almost the entire captured image 13, and the state in which the vehicle C2 overlaps the measurement area 14 will continue, thus allowing the decrease in the light transmittance of the controlled dimming film 3 to be continuously maintained. Figure 8 is a diagram showing the captured image 13 of the foreground seen through the windshield 8. Furthermore, since the system analyzes not only the color information of the vehicle C2 ahead but also the color information of the road surface, it can reduce the transparency of the controlled dimming film 3 even when the partial image 10b is obscured by changes in the road due to fallen leaves, etc., or when the accuracy of the color information analysis decreases due to increased brightness caused by the whiteness of snowy roads.

[0020] (Effects of this embodiment) (1) In this embodiment, the HUD2 is mounted on the vehicle C1 and projects content video 10 onto a projection area 9, which is a specific area of ​​the windshield 8 of the vehicle C1; the imaging device 4 is mounted on the vehicle C1 and images the area in front of the vehicle C1; and the controlled dimming film 3 (dimming unit) is positioned in front of the vehicle C1, beyond the in-cabin surface of the windshield 8, and adjusts the transmittance of light from the front of the vehicle C1 toward the projection area 9. Based on the image data output from the imaging device 4, the controlled dimming film 3 is controlled to improve the visibility of the content video 10. As a result, for example, as shown in Figure 8, when it is determined that the color of the content video 10 displayed on the HUD2 is the same as or similar to the colors included in the foreground, the controlled dimming film 3 reduces the transmittance (transparency) of light, thereby changing the color tone of the foreground when viewed by the occupants of the vehicle C1 through the projection area 9, preventing the content video 10 from being buried in the foreground and preventing the content video 10 from becoming difficult to see in the foreground. As a result, the visibility of the content video 10 can be improved. On the other hand, as a comparative example, as shown in Figure 9, if the reduction in light transmittance by the controlled dimming film 3 is not performed, the content video 10 becomes buried in the foreground. Figure 9 is a diagram showing the foreground image 13 taken through the windshield 8 of the comparative example.

[0021] (2) In this embodiment, the color information of a partial image 17 is obtained from the image data, which is the image shown by the image data (image 13), and is visible through the area of ​​the windshield 8 located above the projection area 9 when viewed from the driver's seat of vehicle C1 (measurement area 14). Based on the obtained color information, the controlled dimming film 3 (dimming unit) is controlled. As a comparative example, if the configuration is set up to obtain the color information of the entire image 13, the time required for color information analysis (digitization and judgment) increases. In contrast, in this embodiment, since the configuration is set up to obtain the color information of a partial image 17, the time required for color information analysis can be shortened. Also, since the partial image 17 is an image visible through the area of ​​the windshield 8 located above the projection area 9, for example, when a vehicle C2 traveling ahead approaches vehicle C1, the transmittance control based on the color information of the vehicle C2 traveling ahead can be started just before the vehicle C2 traveling ahead and the projection area 9 overlap in the image 13. Furthermore, this control of light transmission continues even after the distance between vehicles becomes even shorter and the vehicle C2 ahead overlaps with the projection area 9.

[0022] (3) In this embodiment, in addition to color information, the controlled dimming film 3 (dimming unit) is controlled using luminance information output from the illuminance meter 6, which detects the intensity of ambient light directed toward the measurement area 13. This allows the transparency of the controlled dimming film 3 to be further reduced when, for example, as shown in Figure 10, the intensity of light irradiated onto the windshield 8 by sunlight or the headlights of oncoming vehicles increases, reducing the light blocking ability of the controlled dimming film 3. Therefore, the visibility of the content image 10 can be further improved. Figure 10 shows the windshield 8, projection area 13, and content image 10 when the headlights of oncoming vehicles are strong. On the other hand, as a comparative example, as shown in Figure 11, if the light transmittance of the controlled dimming film 3 is not further reduced, the controlled dimming film 3 cannot block ambient light, and the visibility of the content image 10 decreases. Figure 11 shows the windshield 8, projection area 13, and content image 10 in a comparative example when the headlights of oncoming vehicles are strong.

[0023] (modified version) (1) In this embodiment, an example is shown in which the position of the measurement area 14 is fixed, but other configurations can also be adopted. For example, as shown in Figure 12, the distance L between the projection area 9 and the measurement area 14 may be set according to the vehicle speed of the vehicle C1. Figure 12 illustrates a case in which S201 is placed between S101 and S102, and the distance L is set in S201, and the processing from S102 onwards is performed using the measurement area 14 located at the set distance L. The distance L is increased, for example, as the vehicle speed of the vehicle C1 increases. This makes it possible to start the control of transmittance based on color information earlier, for example, when the vehicle speed of the vehicle C1 is high. Figure 12 is a flowchart showing the overall flow of the display control method of a modified example.

[0024] (2) In this embodiment, an example is shown in which the measurement area 14 is placed above the partial image 10b, but other configurations can also be adopted. For example, as shown in Figure 13, the image data output from the imaging device 4 is used to acquire color information of the partial image images 17a and 17b that are visible through the area of ​​the windshield 8 located above the partial image areas 18a and 18b (measurement areas 13a and 13b), respectively, where the partial images 10a and 10b of the projection area 9 are displayed, and the controllable dimming film 3 is controlled based on the acquired color information. Figure 13 illustrates the case in which the measurement area 13a is placed above the partial image area 18a and the measurement area 13b is placed above the partial image area 18b.

[0025] The partial images 10a and 10b are multiple partial images with different colors included in the content image 10. Figure 13 shows a modified example of the windshield 8, projection area 9, and content image 10. Figure 13 illustrates the case where partial image 10a is white and partial image 10b is red. When the above configuration is adopted, the dimming film control unit 12 determines whether the color information of the partial image 17a contains the same or similar color as the color of the partial image 10a. If it determines that the same or similar color is included, it applies a voltage to the controlled dimming film 3 to reduce the transmittance of the entire controlled dimming film 3 or the partial image area 18a. It also determines whether the color information of the partial image 17b contains the same or similar color as the color of the partial image 10b. If it determines that the same or similar color is included, it applies a voltage to the controlled dimming film 3 to reduce the transmittance of the entire controlled dimming film 3 or the partial image area 18b. This allows for handling cases where multiple colors are used in the content video 10, and enables control of transmittance based on the color information of the foreground of the vehicle C1. When controlling the transmittance of partial video areas 18a and 18b, a controllable dimming film 3 is adopted that allows the transmittance of the projection area 9 to be changed for each partial video area 18a and 18b, or for each pixel. On the other hand, as a comparative example, as shown in Figure 14, if the light transmittance is not reduced by the controllable dimming film 3, the content video 10 is embedded in the foreground. Figure 14 is a diagram showing the captured image 13 of the foreground through the windshield 8 of the comparative example. [Explanation of Symbols]

[0026] 1…Information display system, 2…HUD, 3…Controlled dimming film, 4…Imaging device, 5…Display control device, 6…Illuminance meter, 7…Dimming glass, 8…Windshield, 8a…Glass plate, 8b…Glass plate, 8c…Transparent sheet, 9…Projection area, 10…Content video, 10a, 10b…Partial video, 11…Color analyzer, 12…Dimming film control unit, 13…Captured image, 13a…Measurement area, 13b…Measurement area, 14…Measurement area, 15…First scan line, 16…Second scan line, 17…Partial captured image, 18a…Partial video area, 18b…Partial video area

Claims

1. A display control method for a display control system comprising: a head-up display mounted in a vehicle and projecting content images onto a projection area which is a specific area of ​​the vehicle's windshield; an imaging device mounted in the vehicle and capturing images of the area in front of the vehicle; and a dimming unit positioned in front of the vehicle beyond the in-vehicle surface of the windshield and adjusting the transmittance of light from the front of the vehicle toward the projection area, wherein Based on the image data output from the imaging device, the dimming unit is controlled to improve the visibility of the content video. Display control method.

2. From the image data, the color information of a portion of the captured image, which is the image shown by the image data, is obtained from the measurement area, which is the area of ​​the windshield located above the projection area when viewed from the driver's seat of the vehicle looking forward, and the dimming unit is controlled based on the obtained color information. The display control method according to claim 1.

3. In addition to the aforementioned color information, the dimming unit is controlled using luminance information output from an illuminance meter that detects the intensity of ambient light directed toward the measurement area. The display control method according to claim 2.

4. The distance between the projection area and the measurement area is set according to the vehicle speed. The display control method according to claim 2.

5. The aforementioned content video includes multiple partial images with different colors from each other. From the image data, for each of the partial image regions within the projection region where the partial image is displayed, the color information of the partial image captured is obtained through the area of ​​the windshield located above the partial image region, and the dimming unit is controlled based on the obtained color information. The display control method according to claim 1.

6. A head-up display mounted in a vehicle, which projects content images onto a projection area that is a specific area of ​​the vehicle's windshield, An imaging device mounted on the aforementioned vehicle and for imaging the area in front of the vehicle, A dimming unit is positioned on the vehicle-front side of the windshield's interior surface and adjusts the transmittance of light from the front of the vehicle toward the projection area. The display control device includes a display control device that controls the dimming unit based on image data output from the imaging device so as to improve the visibility of the content video. Display control system.

Images