Drawing control device

Abstract

A drawing control device (1) comprises: a drawing pattern determination unit (12) that determines a drawing pattern to be drawn on a road surface; a color information acquisition unit (10) that acquires color information indicating the color of the road surface as detected by a camera (2) that detects the color of the road surface; an analysis unit (11) that analyzes the reflection intensity of each of a plurality of color components on the road surface on the basis of the color information acquired by the color information acquisition unit (10); and an irradiation intensity determination unit (13) that determines, on the basis of the analysis result from the analysis unit (11), the irradiation intensity of each of the plurality of color components included in irradiation light radiated onto the road surface to draw the drawing pattern. The irradiation intensity determination unit (13) determines the irradiation intensity of each of the plurality of color components included in the irradiation light such that, among the plurality of color components, the irradiation intensity of at least one color component having a reflection intensity equal to or greater than a predetermined intensity threshold value is higher than the irradiation intensity of a color component having a reflection intensity less than the intensity threshold value.

Description

Drawing control device

[0001] The present disclosure relates to a drawing control device.

[0002] A drawing control device that controls drawing on a road surface by irradiation light is known. For example, Patent Document 1 discloses a device that controls a laser array so as to emit white light and illumination light that emphasizes a center line or the like when a center line or the like exists on the road surface.

[0003] Japanese Patent Application Laid-Open No. 2020-17530

[0004] However, the device of Patent Document 1 does not change the color of the irradiation light according to the color of the road surface. Depending on the color of the road surface, the irradiated light on the road surface becomes difficult to see, so there is a problem that the drawing pattern drawn on the road surface by the light becomes difficult to see.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a drawing control device capable of suppressing the difficulty of seeing a drawing pattern drawn by irradiation light irradiated on a road surface.

[0006] The drawing control device according to the present disclosure includes a drawing pattern determination unit that determines a drawing pattern to be drawn on a road surface, a color information acquisition unit that acquires color information indicating the color of the road surface detected by a detector that detects the color of the road surface, an analysis unit that analyzes the reflection intensity of each of a plurality of color components on the road surface based on the color information acquired by the color information acquisition unit, and an irradiation intensity determination unit that determines the irradiation intensity of each of the plurality of color components included in the irradiation light for irradiating the road surface to draw the drawing pattern based on the analysis result of the analysis unit. The irradiation intensity determination unit determines the irradiation intensity of each of the plurality of color components included in the irradiation light such that the irradiation intensity of at least one color component whose reflection intensity is equal to or higher than a predetermined intensity threshold is higher than the irradiation intensity of a color component whose reflection intensity is lower than the intensity threshold.

[0007] According to the present disclosure, it is possible to suppress the difficulty of seeing a drawing pattern drawn by irradiation light irradiated on a road surface.

[0008] This is a block diagram showing the drawing control device, etc., according to Embodiment 1. This is a block diagram showing the functional configuration of the drawing control device in Figure 1. This is a flowchart showing an example of the operation of the drawing control device in Figure 1. This is an explanatory diagram for explaining the operation of Figure 3. This is a block diagram showing the functional configuration of the drawing control device according to Embodiment 2. This is a flowchart showing an example of the operation of the drawing control device in Figure 5. This is a flowchart continuing from Figure 6. This is an explanatory diagram for explaining the operation of Figure 6. This is an explanatory diagram for explaining the operation of Figure 6. This is an explanatory diagram for explaining the operation of Figure 6. This is a timing chart showing an example of the operation of the drawing control device in Figure 5. This is a block diagram showing the functional configuration of the drawing control device according to Embodiment 3. This is a flowchart showing an example of the operation of the drawing control device in Figure 13. This is an explanatory diagram for explaining the operation of Figure 14.

[0009] (Embodiment 1) Embodiment 1 will be described below with reference to the drawings.

[0010] Embodiment 1 adjusts the color components of the light used to draw on the road surface according to the color information of the road surface acquired by the camera, thereby making the drawing pattern drawn on the road surface easier to see, or reducing power consumption while ensuring visibility.

[0011] Figure 1 is a block diagram showing the drawing control device 1, etc., according to Embodiment 1. First, an overview of the drawing control device 1, etc., will be described with reference to Figure 1.

[0012] The drawing control device 1 is a device that controls the drawing of a pattern on the road surface using irradiated light. The camera 2 is an example of a detector that detects the color of the road surface. The irradiated light device 3 is a device that irradiates the road surface with irradiated light. The drawing control device 1 acquires color information indicating the color detected by the camera 2 and controls the irradiated light device 3 based on the acquired color information, thereby controlling the drawing of the pattern on the road surface using irradiated light. For example, the drawing control device 1, camera 2, and irradiated light device 3 are mounted on a vehicle. In this case, the camera 2 is positioned to photograph the road surface around the vehicle and detects the color of the road surface around the vehicle. The irradiated light device 3 is positioned to irradiate the road surface around the vehicle with irradiated light and draws the pattern on the road surface around the vehicle.

[0013] Figure 2 is a block diagram showing the functional configuration of the drawing control device 1 in Figure 1. Next, the functional configuration of the drawing control device 1 will be described with reference to Figure 2.

[0014] As shown in Figure 2, the drawing control device 1 includes a color information acquisition unit 10, an analysis unit 11, a drawing pattern determination unit 12, and an irradiation intensity determination unit 13. For example, the color information acquisition unit 10, the analysis unit 11, the drawing pattern determination unit 12, and the irradiation intensity determination unit 13 are implemented by a processing circuit. The processing circuit may be dedicated hardware or a processor that executes a program stored in memory.

[0015] The color information acquisition unit 10 acquires color information indicating the color of the road surface detected by the camera 2. The camera 2 receives reflected light reflected from the road surface and outputs signal values ​​corresponding to the reflection intensity of each of the multiple color components contained in the reflected light on the road surface. The color information acquisition unit 10 acquires these signal values ​​as color information. In this embodiment, the multiple color components are a red component, a green component, and a blue component. In the following description and figures, the reflection intensity on the road surface may be simply referred to as reflection intensity. Also, the red component may be indicated by R, the green component by G, and the blue component by B.

[0016] The analysis unit 11 analyzes the reflectance intensity of each of the multiple color components based on the color information acquired by the color information acquisition unit 10. Specifically, the analysis unit 11 analyzes whether the reflectance intensity of each of the multiple color components is equal to or greater than a predetermined intensity threshold. In this embodiment, the intensity threshold is set to a predetermined ratio to the reflectance intensity of the color component with the highest reflectance intensity among the multiple color components. For example, if the predetermined ratio is 20 percent, and the reflectance intensity of R is the highest among R, G, and B, the intensity threshold is set to 20 percent of the reflectance intensity of R. Note that the intensity threshold may be a predetermined absolute value, rather than a relative value of the reflectance intensity of the color component with the highest reflectance intensity among the multiple color components.

[0017] The drawing pattern determination unit 12 determines the drawing pattern to be drawn on the road surface. The drawing pattern may be a figure, a character, or a combination thereof, and may include color. For example, the drawing pattern determination unit 12 determines the drawing pattern based on user operation. Specifically, if the user performs an operation to reverse the vehicle, the drawing pattern determination unit 12 determines the drawing pattern to be an arrow pointing towards the rear of the vehicle, or a string of characters indicating that the vehicle is reversing. Also, if the user performs an operation to turn the vehicle left, the drawing pattern determination unit 12 determines the drawing pattern to be an arrow pointing to the left of the vehicle, or a string of characters indicating that the vehicle is turning left. An operation to reverse the vehicle is an operation to position the vehicle's shift lever in the reverse position. An operation to turn the vehicle left is an operation to turn on the left turn signal of the vehicle.

[0018] The irradiation intensity determination unit 13 determines the irradiation intensity of each of the multiple color components contained in the irradiation light that is irradiated onto the road surface to draw a drawing pattern, based on the analysis results of the analysis unit 11. Specifically, the irradiation intensity determination unit 13 determines the irradiation intensity of each of the multiple color components contained in the irradiation light such that the irradiation intensity of at least one color component whose reflectance intensity is equal to or greater than the intensity threshold is higher than the irradiation intensity of the color component whose reflectance intensity is less than the intensity threshold. For example, if the analysis unit 11 analyzes that the reflectance intensity of R is equal to or greater than the intensity threshold, and the reflectance intensities of G and B are less than the intensity threshold, the irradiation intensity determination unit 13 determines the irradiation intensities of R, G, and B contained in the irradiation light such that the irradiation intensity of R is higher than the irradiation intensities of G and B. In this case, the irradiation intensity determination unit 13 may set the irradiation intensities of G and B to 0, or to a predetermined ratio to the irradiation intensity of R, or to a predetermined ratio to the irradiation intensity of R, etc. Furthermore, if the drawing pattern determination unit 12 has also determined the color of the drawing pattern, the irradiation intensity determination unit 13 adjusts the color determined by the drawing pattern determination unit 12 and determines the irradiation intensity of each of the multiple color components included in the irradiation light such that the irradiation intensity of at least one color component whose reflection intensity is equal to or greater than the intensity threshold is higher than the irradiation intensity of the color component whose reflection intensity is less than the intensity threshold.

[0019] The illumination intensity determination unit 13 determines the illumination intensity of each of the multiple color components contained in the illumination light to be irradiated onto the road surface in order to draw a drawing pattern, and then transmits a control signal to the illumination device 3 to irradiate the road surface with the illumination light at the determined illumination intensity. Based on the control signal, the illumination device 3 irradiates the road surface with the illumination intensity determined by the illumination intensity determination unit 13. As a result, the road surface is irradiated with the illumination intensity determined by the illumination intensity determination unit 13, and a drawing pattern is drawn on the road surface by the illumination light. For example, the illumination device 3 has multiple light source modules, each of which has a light source that emits red light, a light source that emits green light, and a light source that emits blue light. In this case, the illumination device 3 irradiates the road surface with the illumination intensity determined by the illumination intensity determination unit 13 by setting the intensity of the light emitted from each light source of each light source module to the illumination intensity determined by the illumination intensity determination unit 13.

[0020] Figure 3 is a flowchart illustrating an example of the operation of the drawing control device 1 shown in Figure 1. Figure 4 is an explanatory diagram illustrating the operation shown in Figure 3. Next, an example of the operation of the drawing control device 1 will be described with reference to Figures 3 and 4.

[0021] As shown in Figure 3, the drawing pattern determination unit 12 determines the drawing pattern to be drawn on the road surface (step S1). For example, when a user performs an operation that requires the drawing of a pattern, the drawing pattern determination unit 12 determines the drawing pattern to be drawn on the road surface. Such operations include, as described above, operations to reverse the vehicle or operations to turn the vehicle left.

[0022] The color information acquisition unit 10 acquires color information indicating the color of the road surface detected by the camera 2 (step S2). For example, when a user performs an operation that requires the drawing of a drawing pattern, the drawing pattern determination unit 12, etc., determines the location where the drawing pattern will be drawn according to the type of operation, and the color information acquisition unit 10 acquires color information indicating the color of the road surface detected by the camera 2 that photographs that location. If the operation is to reverse the vehicle, the location where the drawing pattern will be drawn is determined to be the road surface behind the vehicle. If the operation is to turn the vehicle left, the location where the drawing pattern will be drawn is determined to be the road surface diagonally in front of the left of the vehicle.

[0023] The analysis unit 11 analyzes the reflectance intensity of each of the multiple color components on the road surface based on the color information acquired by the color information acquisition unit 10 (step S3). As described above, the analysis unit 11 analyzes whether the reflectance intensity of each of the multiple color components is above an intensity threshold.

[0024] The irradiation intensity determination unit 13 determines the irradiation intensity of each of the multiple color components contained in the irradiation light that is irradiated onto the road surface to draw the drawing pattern, based on the analysis results of the analysis unit 11 (step S4). As described above, the irradiation intensity determination unit 13 determines the irradiation intensity of the multiple color components contained in the irradiation light such that the irradiation intensity of at least one color component whose reflectance intensity is equal to or greater than the intensity threshold is higher than the irradiation intensity of the color component whose reflectance intensity is less than the intensity threshold.

[0025] The irradiation intensity determination unit 13 sends a control signal to the irradiation device 3 so that it irradiates the road surface with the determined irradiation intensity, and draws the drawing pattern on the road surface (step S5).

[0026] For example, as shown in Figure 4(a), if the road surface 100 is yellow, the analysis unit 11 analyzes the reflectance of R, G, and B based on the color information acquired by the color information acquisition unit 10. Here, the intensity threshold is set to 20 percent of the reflectance of R, which has the highest reflectance among R, G, and B. Therefore, the analysis unit 11 sets the reflectance of R to 100% and analyzes whether the reflectance of G and B is equal to or greater than the intensity threshold. Here, the analysis unit 11 analyzes that the reflectance of R and G is equal to or greater than the intensity threshold, and that the reflectance of B is less than the intensity threshold.

[0027] As shown in Figure 4(b), the irradiation intensity determination unit 13 determines the irradiation intensities of R, G, and B based on the analysis results of the analysis unit 11, such that the irradiation intensities of R and G, whose reflectance is above the intensity threshold, are higher than the irradiation intensity of B, whose reflectance is below the intensity threshold. Here, the irradiation intensity determination unit 13 determines the irradiation intensities of R and G to be the same level, and the irradiation intensity of B to be 0. The irradiation intensity determination unit 13 may also include only one of R and G in the irradiation light and determine the irradiation intensity of the other R and G to be 0. Alternatively, the irradiation intensity determination unit 13 may set the irradiation intensity of one of R and G lower than the irradiation intensity of the other R and G. The irradiation device 3 irradiates the road surface 100 with the determined irradiation intensities and draws the drawing pattern 200 on the road surface 100.

[0028] As described above, the drawing control device 1 according to Embodiment 1 includes a drawing pattern determination unit 12 that determines a drawing pattern to be drawn on the road surface, a color information acquisition unit 10 that acquires color information indicating the color of the road surface detected by a camera 2 that detects the color of the road surface, an analysis unit 11 that analyzes the reflection intensity of each of the multiple color components on the road surface based on the color information acquired by the color information acquisition unit 10, and an irradiation intensity determination unit 13 that determines the irradiation intensity of each of the multiple color components included in the irradiation light that is irradiated onto the road surface in order to draw the drawing pattern based on the analysis results of the analysis unit 11. The irradiation intensity determination unit 13 determines the irradiation intensity of each of the multiple color components included in the irradiation light such that the irradiation intensity of at least one color component whose reflection intensity is above a predetermined intensity threshold is higher than the irradiation intensity of the color component whose reflection intensity is below the intensity threshold.

[0029] According to this method, the illumination intensity of each of the multiple color components included in the illumination light is determined such that the illumination intensity of at least one color component whose reflectance intensity is above a predetermined intensity threshold is higher than the illumination intensity of the color components whose reflectance intensity is below the intensity threshold. Therefore, the color components with relatively high reflectance among the multiple color components included in the illumination light are efficiently reflected from the road surface, thus suppressing the difficulty in seeing the drawing pattern drawn by the illumination light. In addition, since the illumination intensity of the color components whose reflectance intensity is below the intensity threshold is lower than the illumination intensity of the color components whose reflectance intensity is above the intensity threshold, power consumption can be suppressed while suppressing the difficulty in seeing the drawing pattern drawn by the illumination light.

[0030] Furthermore, in the drawing control device 1 according to Embodiment 1, the intensity threshold is set to a predetermined ratio to the reflectance of the color component with the highest reflectance among the multiple color components.

[0031] According to this method, it is possible to suppress the intensity threshold from becoming too high or too low relative to the reflectance intensity, thereby enabling a more appropriate determination of the illumination intensity and further suppressing the difficulty in seeing the drawing pattern created by the illuminated light.

[0032] (Embodiment 2) Embodiment 2 will be described below with reference to the drawings. The following description will focus on the differences from Embodiment 1.

[0033] Figure 5 is a block diagram showing the functional configuration of the drawing control device 1a according to Embodiment 2. First, the functional configuration of the drawing control device 1a will be described with reference to Figure 5.

[0034] As shown in Figure 5, the drawing control device 1a differs from the drawing control device 1 mainly in that it includes an illumination intensity determination unit 13a instead of an illumination intensity determination unit 13, and further includes an illuminance information acquisition unit 14a and a control unit 15a. For example, the illumination intensity determination unit 13a, the illuminance information acquisition unit 14a, and the control unit 15a are implemented by a processing circuit together with the color information acquisition unit 10, the analysis unit 11, and the drawing pattern determination unit 12. The processing circuit may be dedicated hardware or a processor that executes a program stored in memory.

[0035] The illumination intensity determination unit 13a determines the illumination intensity of each of the multiple color components included in the light used to draw the frame portion along the edge of the drawing pattern, such that the illumination intensity of at least one color component whose reflected intensity is equal to or greater than the intensity threshold is higher than the illumination intensity of the color component whose reflected intensity is less than the intensity threshold. For example, depending on the location where the drawing pattern is drawn, the color of the drawing pattern may be specified, and the specified color may not reflect well from the road surface. In this case, the drawing pattern is made to include a frame portion and a portion inside the frame portion, and the illumination intensity determination unit 13a determines the illumination intensity of each of the multiple color components included in the light used to draw the frame portion as described above, and sets the light used to draw the portion inside the frame portion to the specified color as described above. This makes the frame portion of the drawing pattern easier to see even when the specified color does not reflect well from the road surface, thereby suppressing the drawing pattern from becoming difficult to see.

[0036] Furthermore, when the road surface has multiple colors, the irradiation intensity determination unit 13a determines the irradiation intensity of the multiple color components included in the irradiation light such that the irradiation intensity of the color component is the highest among the multiple color components if there is a color component among the multiple color components in which the reflectance intensity is equal to or greater than the intensity threshold in any region of the multiple colors. For example, when the road surface has three colors, if the reflectance intensity of R is equal to or greater than the intensity threshold in each region of the three colors, the irradiation intensity of the multiple color components included in the irradiation light is determined such that the irradiation intensity of R is the highest among R, G, and B.

[0037] Furthermore, when the road surface has multiple colors, the irradiation intensity determination unit 13a determines the irradiation intensity of multiple color components included in the irradiation light such that, for each region of the multiple colors, the irradiation intensity of at least one color component whose reflectance intensity in that region is equal to or greater than the intensity threshold is higher than the irradiation intensity of the color components whose reflectance intensity in that region is less than the intensity threshold. For example, when the road surface has three colors, in the region of the first color, the reflectance intensity of R is equal to or greater than the intensity threshold and the reflectance intensities of G and B are less than the intensity threshold; in the region of the second color, the reflectance intensity of B is equal to or greater than the intensity threshold and the reflectance intensities of R and G are less than the intensity threshold; and in the region of the third color, the reflectance intensity of G is equal to or greater than the intensity threshold and the reflectance intensities of R and B are less than the intensity threshold. In this case, the irradiation intensity determination unit 13a determines the irradiation intensity of multiple color components included in the irradiation light such that, for the region of the first color, the irradiation intensity of R is higher than the irradiation intensities of G and B. Furthermore, the irradiation intensity determination unit 13a determines the irradiation intensity of multiple color components included in the irradiation light such that the irradiation intensity of B is higher than the irradiation intensities of R and G for the second color region. Furthermore, the irradiation intensity determination unit 13a determines the irradiation intensity of multiple color components included in the irradiation light such that the irradiation intensity of G is higher than the irradiation intensities of R and B for the third color region. When the road surface has multiple colors, if there is no color component among the multiple color components whose reflectance intensity is above the intensity threshold in any region of the multiple colors, the irradiation intensity determination unit 13a determines the irradiation intensity of each of the multiple color components for each region in this manner. Note that when the road surface has multiple colors, if there is a color component among the multiple color components whose reflectance intensity is above the intensity threshold in any region of the multiple colors, the irradiation intensity determination unit 13a may determine the irradiation intensity of each of the multiple color components for each region in this manner, rather than making the irradiation intensity of that color component the highest among the multiple color components.

[0038] Furthermore, when the color of the irradiated light differs between two adjacent regions, the irradiation intensity determination unit 13a determines the irradiation intensity of each of the multiple color components contained in the irradiated light so that the color changes in a gradient manner from the color irradiated to one region to the color irradiated to the other region in the portion including the boundary between the two regions. For example, if the color of the irradiated light illuminating one of two adjacent regions is red and the color of the irradiated light illuminating the other region is blue, the irradiation intensity determination unit 13a determines the irradiation intensity of the multiple color components contained in the irradiated light so that the color changes in a gradient manner from red to blue in the portion including the boundary between the two regions.

[0039] The illuminance information acquisition unit 14a acquires illuminance information indicating the illuminance measured by the illuminance sensor 4a. The illuminance sensor 4a is an example of a measuring instrument for measuring the illuminance of the road surface. For example, the illuminance sensor 4a is installed on the outside of a vehicle or elsewhere to measure illuminance.

[0040] If the illuminance information acquired by the illuminance information acquisition unit 14a is below a predetermined illuminance threshold, the control unit 15a instructs the luminaire 5a to illuminate the road surface with white light for a period shorter than the period during which a person can perceive white light, and outputs a synchronization signal to the color information acquisition unit 10 that is synchronized with the illumination of white light by the luminaire 5a. The period during which a person can perceive white light is approximately 20 milliseconds. The synchronization signal indicates the timing of the illumination of white light by the luminaire 5a.

[0041] The color information acquisition unit 10 acquires color information indicating the color of the road surface detected by the camera 2 when the lamp 5a illuminates the road surface with white light, based on the synchronization signal output by the control unit 15a. The color information acquisition unit 10 knows the timing of when the lamp 5a illuminates the road surface with white light from the synchronization signal, and therefore can acquire color information indicating the color of the road surface detected by the camera 2 when the lamp 5a illuminates the road surface with white light. Note that the illuminance sensor 4a can be replaced by the camera 2.

[0042] FIG. 6 is a flowchart showing an example of the operation of the drawing control device 1a in FIG. 5. FIG. 7 is a flowchart showing the continuation of FIG. 6. Each of FIGS. 8 to 11 is an explanatory diagram for explaining the operation of FIG. 6. FIG. 12 is a timing chart showing an example of the operation of the drawing control device 1a in FIG. 5. Next, an example of the operation of the drawing control device 1a will be described with reference to FIGS. 6 to 12.

[0043] As shown in FIG. 6, the drawing pattern determination unit 12 determines a drawing pattern to be drawn on the road surface (step S11). The drawing pattern determination unit 12 determines the drawing pattern in the same manner as step S1 described above.

[0044] The control unit 15a determines whether the road surface is dark (step S12). For example, when the illuminance indicated by the illuminance information acquired by the illuminance information acquisition unit 14a is less than the illuminance threshold, the control unit 15a determines that the road surface is dark, and when the illuminance is greater than or equal to the illuminance threshold, the control unit 15a determines that the road surface is not dark. Here, the road surface being dark means a state in which the color information of the road surface cannot be correctly recognized by the camera 2 to a practically acceptable degree.

[0045] When the road surface is dark (YES in step S12), the control unit 15a irradiates white light (step S13). Here, the white light is irradiated for a period shorter than about 20 milliseconds so that people do not notice the irradiation of the white light. As described above, the control unit 15a irradiates the road surface with white light by instructing the lamp unit 5a to irradiate the road surface with white light.

[0046] When the road surface is not dark (NO in step S12) or when white light is irradiated (step S13), the color information acquisition unit 10 acquires color information indicating the color of the road surface detected by the camera 2 (step S14). When white light is irradiated, the color information acquisition unit 10 acquires color information indicating the color of the road surface detected by the camera 2 when the lamp unit 5a irradiates the road surface with white light, as described above.

[0047] The analysis unit 11 analyzes the reflection intensity of each of the plurality of color components on the road surface based on the color information acquired by the color information acquisition unit 10 (step S15). The analysis unit 11 analyzes the reflection intensity in the same manner as in step S3 described above.

[0048] The irradiation intensity determination unit 13a determines the irradiation intensity of the plurality of color components included in the irradiation light irradiated onto the road surface for drawing the drawing pattern based on the analysis result of the analysis unit 11.

[0049] The irradiation intensity determination unit 13a determines whether the road surface has a plurality of colors (step S16). When the road surface does not have a plurality of colors (NO in step S16), that is, when the road surface is a single color, among the plurality of color components, the irradiation intensity of at least one color component whose reflection intensity is equal to or higher than the intensity threshold is higher than the irradiation intensity of the color component whose reflection intensity is lower than the intensity threshold. The irradiation intensity of the plurality of color components included in the irradiation light is determined (step S17).

[0050] When the road surface has a plurality of colors (YES in step S16), that is, when the road surface is not a single color, the irradiation intensity determination unit 13a determines whether there is a common color component whose reflection intensity is equal to or higher than the intensity threshold in any region of the plurality of colors (step S18).

[0051] When there is a common color component whose reflection intensity is equal to or higher than the intensity threshold in any region of the plurality of colors (YES in step S18), among the plurality of color components, the irradiation intensity of the common color component whose reflection intensity is equal to or higher than the intensity threshold in any region of the plurality of colors is made the highest. The irradiation intensity of the plurality of color components included in the irradiation light is determined (step S19).

[0052] When there is no common color component whose reflection intensity is equal to or higher than the intensity threshold in any region of the plurality of colors (NO in step S18), for each region of the plurality of colors, the irradiation intensity of the color component whose reflection intensity is equal to or higher than the intensity threshold in that region is higher than the irradiation intensity of the color component whose reflection intensity is lower than the intensity threshold in that region. The irradiation intensity of the plurality of color components included in the irradiation light is determined respectively (step S20).

[0053] The irradiation intensity determination unit 13a determines the irradiation intensity of multiple color components contained in the irradiation light so that the color changes in a gradient manner (step S21). As described above, when the color of the irradiation light is different in one of two adjacent regions, the irradiation intensity determination unit 13a determines the irradiation intensity of each of the multiple color components contained in the irradiation light so that the color changes in a gradient manner from the color irradiated to one region to the color irradiated to the other region in the portion including the boundary between the two regions.

[0054] The irradiation intensity determination unit 13a determines whether or not to adjust the color of the frame (step S22). For example, as described above, if the color of the drawing pattern is specified by the drawing pattern determination unit 12 or the like, the irradiation intensity determination unit 13a determines to adjust the color of the frame. On the other hand, if the color of the drawing pattern is not specified, the irradiation intensity determination unit 13a determines not to adjust the color of the frame.

[0055] If the irradiation intensity determination unit 13a determines that the color of the frame does not need to be adjusted (NO in step S22), it adjusts the color of the drawing pattern (step S23). The irradiation intensity determination unit 13a adjusts the color of the drawing pattern by determining the irradiation intensity of each of the multiple color components contained in the irradiation light for drawing the entire drawing pattern to the irradiation intensity determined in step S17, step S19, or steps S20, S21.

[0056] If the irradiation intensity determination unit 13a determines that the color of the frame should be adjusted (YES in step S22), it adjusts the color of the frame of the drawing pattern (step S24). The irradiation intensity determination unit 13a adjusts the color of the frame of the drawing pattern by determining the irradiation intensity of each of the multiple color components contained in the light used to draw the frame along the edge of the drawing pattern from the irradiation light to the irradiation intensity determined in step S17, step S19, or steps S20, S21.

[0057] The irradiation intensity determination unit 13a sends a control signal to the irradiation device 3 so that it irradiates the road surface with the determined irradiation intensity, and draws the drawing pattern on the road surface (step S25).

[0058] For example, as shown in Figure 8(a), if the road surface 100a has multiple colors, the analysis unit 11 analyzes the respective reflectance intensities of R, G, and B for each of the multiple color regions 101a and 102a based on the color information acquired by the color information acquisition unit 10. Here, the intensity threshold is set to 20 percent of the reflectance intensity of B, which has the highest reflectance among R, G, and B, for region 101a, and to 20 percent of the reflectance intensity of R, G, or B, which has the highest reflectance among R, G, and B, for region 102a. Therefore, the analysis unit 11 analyzes that for region 101a, the reflectance intensities of R and G are below the intensity threshold, and the reflectance intensity of B is equal to or greater than the intensity threshold. The analysis unit 11 also analyzes that for region 102a, the reflectance intensities of R, G, and B are equal to or greater than the intensity threshold.

[0059] Here, among R, G, and B, there exists a common color component B whose reflectance intensity is above the intensity threshold in any of the regions 101a, 102a of multiple colors. Therefore, as shown in Figure 8(b), the irradiation intensity determination unit 13a determines the irradiation intensities of R, G, and B based on the analysis results of the analysis unit 11, such that in any of the regions 101a, 102a, the irradiation intensity of B, whose reflectance intensity is above the intensity threshold, is the highest among R, G, and B, and is higher than the irradiation intensities of R and G, whose reflectance intensity is below the intensity threshold. Here, the irradiation intensity determination unit 13a determines the irradiation intensities of R and G to be 0. The irradiation device 3 irradiates the road surface 100a with the determined irradiation intensities and draws the drawing pattern 200a on the road surface.

[0060] Furthermore, as shown in Figure 9(a), if the road surface 100b has multiple colors, the analysis unit 11 analyzes the respective reflectance intensities of R, G, and B for each of the multiple color regions 101b and 102b based on the color information acquired by the color information acquisition unit 10. Here, the intensity threshold is set to 20 percent of the reflectance intensity of B, which has the highest reflectance among R, G, and B, for region 101b, and to 20 percent of the reflectance intensity of R, which has the highest reflectance among R, G, and B, for region 102b. For region 101b, the analysis unit 11 analyzes that the reflectance intensities of R and G are below the intensity threshold, and the reflectance intensity of B is equal to or greater than the intensity threshold. Similarly, for region 102b, the analysis unit 11 analyzes that the reflectance intensity of B is below the intensity threshold, and the reflectance intensities of R and G are equal to or greater than the intensity threshold.

[0061] Here, in any of the regions 101b and 102b of the multiple colors R, G, and B, there is no common color component whose reflectance intensity is greater than or equal to the intensity threshold. Therefore, as shown in Figure 9(b), the irradiation intensity determination unit 13a determines the irradiation intensities of R, G, and B in region 101b based on the analysis results of the analysis unit 11, such that the irradiation intensity of B, whose reflectance intensity is greater than or equal to the intensity threshold, is higher than the irradiation intensities of R and G, whose reflectance intensity is less than the intensity threshold. Here, the irradiation intensity determination unit 13a determines the irradiation intensities of R and G to be 0. Also, based on the analysis results of the analysis unit 11, the irradiation intensity determination unit 13a determines the irradiation intensities of R, G, and B in region 102b such that the irradiation intensities of R and G, whose reflectance intensity is greater than or equal to the intensity threshold, are higher than the irradiation intensity of B, whose reflectance intensity is less than the intensity threshold. Here, the irradiation intensity determination unit 13a determines the irradiation intensity of B to be 0. The irradiation intensity determination unit 13a may include only one of R and G in the irradiation light for region 102b, and determine the irradiation intensity of the other R and G to be 0. Alternatively, the irradiation intensity determination unit 13a may set the irradiation intensity of one of R and G lower than the irradiation intensity of the other R and G. The irradiation device 3 irradiates the road surface 100b with the determined irradiation intensity, drawing the pattern 200b on the road surface.

[0062] As shown in Figure 10, if the color of the irradiated light differs between two adjacent regions 101b and 102b, the irradiation intensity determination unit 13a may determine the irradiation intensities of R, G, and B included in the irradiated light in such a way that the color changes in a gradient from the color irradiated to one region 101b to the color irradiated to the other region 102b in the portion including the boundary between the two regions 101b and 102b.

[0063] Furthermore, as shown in Figure 11(a), if the color of the road surface 100c is blue, the analysis unit 11 analyzes the respective reflectance intensities of R, G, and B based on the color information acquired by the color information acquisition unit 10. Here, the intensity threshold is set to 20 percent of the reflectance intensity of B, which has the highest reflectance intensity among R, G, and B. Therefore, the analysis unit 11 sets the reflectance intensity of B to 100% and analyzes whether the reflectance intensities of R and G are equal to or greater than the intensity threshold. Here, the analysis unit 11 analyzes that the reflectance intensity of B is equal to or greater than the intensity threshold, and that the reflectance intensities of R and G are less than the intensity threshold.

[0064] Here, it is assumed that the color of the drawing pattern 200c is specified by the drawing pattern determination unit 12, etc. Therefore, as shown in Figure 11(b), the irradiation intensity determination unit 13a ensures that the drawing pattern 200c includes the frame portion 201c and the portion 202c inside the frame portion 201c. The irradiation intensity determination unit 13a then determines the irradiation intensities of R, G, and B such that the irradiation intensity of B included in the light used to draw the frame portion 201c is higher than the irradiation intensities of R and G. Here, the irradiation intensity determination unit 13a sets the irradiation intensities of R and G to 0. Furthermore, the irradiation intensity determination unit 13a determines the irradiation intensities of R, G, and B such that the light used to draw the portion 202c inside the frame portion 201c becomes the specified color. Here, the irradiation intensity determination unit 13a sets the irradiation intensities of R and G to the same level and sets the irradiation intensity of B to 0. The irradiation device 3 irradiates the road surface with light at a determined irradiation intensity, drawing the pattern 200c on the road surface.

[0065] As shown in Figure 12, if the road surface is dark (YES in step S12 of Figure 6), the camera 2 takes a picture in synchronization with the timing when the light fixture 5a emits white light to detect the color of the road surface, and the color information acquisition unit 10 acquires color information indicating the color detected by the camera 2.

[0066] Subsequently, the analysis unit 11 analyzes the reflection intensity based on the color information, and the irradiation intensity determination unit 13a determines the irradiation intensity, at which point the irradiation device 3 irradiates the road surface with the irradiation light, thereby drawing the pattern on the road surface.

[0067] As described above, the drawing control device 1a according to Embodiment 2 has the same configuration as the drawing control device 1 according to Embodiment 1, and therefore provides the same effects and advantages as the drawing control device 1 according to Embodiment 1.

[0068] Furthermore, in the drawing control device 1a according to Embodiment 2, the irradiation intensity determination unit 13a determines the irradiation intensity of each of the multiple color components included in the light used to draw the frame portion provided along the edge of the drawing pattern, such that the irradiation intensity of at least one color component whose reflected intensity is equal to or greater than the intensity threshold is higher than the irradiation intensity of the color component whose reflected intensity is less than the intensity threshold.

[0069] According to this, it is possible to suppress the reflection of the light used to draw the frame from the road surface, so even if the color of the drawing pattern is specified, it is possible to draw the drawing pattern in the specified color while suppressing the visibility of the drawing pattern drawn by the illuminated light.

[0070] Furthermore, in the drawing control device 1a according to Embodiment 2, when the road surface has multiple colors, if there is a common color component among the multiple color components in which the reflectance intensity is equal to or greater than the intensity threshold in any region of the multiple colors, the irradiation intensity of each of the multiple color components included in the irradiation light is determined so that the irradiation intensity of that color component is the highest among the multiple color components.

[0071] According to this method, even when the road surface has multiple colors, it is possible to suppress the reduction in the amount of reflected light from the road surface in each of the areas of the multiple colors, thereby preventing the drawing pattern created by the illuminated light from becoming difficult to see. In addition, it is possible to give the drawing pattern a sense of unity.

[0072] Furthermore, in the drawing control device 1a according to Embodiment 2, when the road surface has multiple colors, the irradiation intensity determination unit 13a determines the irradiation intensity of each of the multiple color components included in the irradiation light such that, for each region of the multiple colors, the irradiation intensity of at least one color component whose reflectance intensity in that region is equal to or greater than the intensity threshold is higher than the irradiation intensity of the color component whose reflectance intensity in that region is less than the intensity threshold.

[0073] According to this, even if the road surface has multiple colors, it is possible to suppress the reduction in the amount of light reflected from the road surface in each of the areas of the multiple colors, thereby suppressing the reduction in the visibility of the drawing pattern drawn by the light.

[0074] Furthermore, in the drawing control device 1a according to Embodiment 2, when the color of the irradiated light differs between two adjacent regions, the irradiation intensity determination unit 13a determines the irradiation intensity of each of the multiple color components contained in the irradiated light so that the color changes in a gradient manner from the color irradiated to one region to the color irradiated to the other region in the portion including the boundary between the two regions.

[0075] According to this method, it is possible to suppress the issue of the illuminated light not reflecting off the road surface because the color illuminating one area encroaches on the other area, or vice versa, thus preventing the drawing pattern drawn by the illuminated light from becoming difficult to see.

[0076] Furthermore, the drawing control device 1a according to Embodiment 2 includes an illuminance information acquisition unit 14a that acquires illuminance information indicating the illuminance measured by an illuminance sensor 4a for measuring the illuminance of the road surface, and a control unit 15a that, when the illuminance indicated by the illuminance information acquired by the illuminance information acquisition unit 14a is less than a predetermined illuminance threshold, instructs the lamp 5a to irradiate the road surface with white light for a period shorter than the period during which a person can perceive white light, and outputs a synchronization signal to the color information acquisition unit 10 that is synchronized with the irradiation of white light by the lamp 5a. Based on the synchronization signal, the color information acquisition unit 10 acquires color information indicating the color of the road surface detected by the camera 2 when the lamp 5a irradiates the road surface with white light.

[0077] According to this method, even when the road surface is dark, color information can be acquired, thus suppressing the difficulty in seeing the drawing pattern rendered by the illuminated light.

[0078] (Embodiment 3) Embodiment 3 will be described below with reference to the drawings. In this description, the differences from Embodiment 1 will be the main focus.

[0079] Figure 13 is a block diagram showing the functional configuration of the drawing control device 1b according to Embodiment 3. First, the functional configuration of the drawing control device 1b will be described with reference to Figure 13.

[0080] As shown in Figure 13, the drawing control device 1b differs from the drawing control device 1 mainly in that it further includes an illuminance information acquisition unit 14a and a modification unit 16b. For example, the illuminance information acquisition unit 14a and the modification unit 16b are implemented by a processing circuit together with the color information acquisition unit 10, the analysis unit 11, the drawing pattern determination unit 12, and the irradiation intensity determination unit 13. The processing circuit may be dedicated hardware or a processor that executes a program stored in memory.

[0081] A detailed explanation of the illuminance information acquisition unit 14a will be omitted here, as it can be found by referring to the description of Embodiment 2 above.

[0082] The modification unit 16b modifies the intensity threshold based on the illuminance information acquired by the illuminance information acquisition unit 14a, so that when the illuminance measured by the illuminance sensor 4a is low, the intensity threshold is larger than when the illuminance is high. For example, the modification unit 16b makes the intensity threshold when the illuminance measured by the illuminance sensor 4a is a first illuminance greater than the intensity threshold when the illuminance measured by the illuminance sensor 4a is a second illuminance which is higher than the first illuminance. The modification unit 16b may change the intensity threshold linearly or curvilinearly so that the intensity threshold gradually increases as the illuminance decreases, or it may change the intensity threshold in a stepwise manner so that the intensity threshold increases each time the illuminance falls below a predetermined range.

[0083] When the intensity threshold is changed by the modification unit 16b, the analysis unit 11 performs an analysis based on the intensity threshold changed by the modification unit 16b. Specifically, the analysis unit 11 analyzes whether the reflectance intensity of each of the multiple color components is equal to or greater than the said intensity threshold.

[0084] Figure 14 is a flowchart showing an example of the operation of the drawing control device 1b shown in Figure 13. Next, an example of the operation of the drawing control device 1b will be described with reference to Figure 14.

[0085] As shown in Figure 14, the illuminance information acquisition unit 14a acquires illuminance information indicating the illuminance measured by the illuminance sensor 4a (step S31).

[0086] The modification unit 16b changes the intensity threshold based on the illuminance measured by the illuminance sensor 4a (step S32). For example, the modification unit 16b changes the intensity threshold as described above.

[0087] When the drawing control device 1b performs the operation shown in Figure 3, if the modification unit 16b changes the intensity threshold, the modification unit 16b uses the changed intensity threshold to perform the analysis in step S3.

[0088] For example, as shown in Figure 15(a), the modification unit 16b sets the intensity threshold to A1 when the illuminance measured by the illuminance sensor 4a is a first illuminance. Also, the modification unit 16b sets the intensity threshold to A2, which is smaller than A1, when the illuminance measured by the illuminance sensor 4a is a second illuminance that is higher than the first illuminance.

[0089] When the illuminance measured by the illuminance sensor 4a is the second illuminance, the intensity threshold becomes A2, and the analysis unit 11 analyzes that the reflectance intensities of the multiple color components B1 and B2 are A2 or greater. As a result, as shown in Figure 15(b), the irradiation intensity determination unit 13 can determine the irradiation intensities of B1 and B2 so that the irradiation intensity of B1 and the irradiation intensity of B2 are at the same level.

[0090] On the other hand, if the illuminance measured by the illuminance sensor 4a is the first illuminance, the intensity threshold becomes A1, and the analysis unit 11 analyzes that the reflectance intensity of B1 is A1 or greater, and the reflectance intensity of B2 is less than A1. As a result, as shown in Figure 15(c), the irradiation intensity determination unit 13 can determine the irradiation intensities of B1 and B2 respectively such that the irradiation intensity of B2 becomes 0 and the irradiation intensity of B1 becomes higher than the irradiation intensity of B2.

[0091] When the illuminance measured by the illuminance sensor 4a is the second illuminance, it is brighter than when the illuminance is the first illuminance, so increasing the light intensity compared to when the illuminance is the first makes the drawing pattern easier to see. Also, when the illuminance measured by the illuminance sensor 4a is the first illuminance, it is dimmer than when the illuminance is the second illuminance, so even with less light intensity than when the illuminance is the second, the drawing pattern is less likely to become difficult to see. Here, as described above, when the illuminance is the first, by setting the intensity threshold to A1, the irradiation intensity of B2, which has a relatively low reflectance, can be set to 0, as shown in Figures 15(a) and (c). Therefore, it is possible to reduce the light intensity compared to when the illuminance is the second, thereby suppressing power consumption and preventing the drawing pattern from becoming difficult to see. Furthermore, in the case of the second illuminance, by setting the intensity threshold to A2, as shown in Figures 15(a) and (b), the illumination intensity of B2, which has a relatively low reflectance, can be made to the same level as the illumination intensity of B1. This suppresses the problem of the drawing pattern becoming difficult to see due to an increased amount of light compared to the case of the first illuminance.

[0092] As described above, the drawing control device 1b according to Embodiment 3 has the same configuration as the drawing control device 1 according to Embodiment 1, and therefore provides the same effects and advantages as the drawing control device 1 according to Embodiment 1.

[0093] Furthermore, the drawing control device 1b according to Embodiment 3 includes an illuminance information acquisition unit 14a that acquires illuminance information indicating the illuminance measured by an illuminance sensor 4a for measuring the illuminance of the road surface, and a modification unit 16b that changes the intensity threshold based on the illuminance information acquired by the illuminance information acquisition unit 14a so that the intensity threshold is larger when the illuminance is low compared to when the illuminance is high.

[0094] According to this, when the illuminance is low, compared to when the illuminance is high, increasing the intensity threshold makes it easier to set the reflection intensity of color components with relatively low reflection intensity below the intensity threshold, and thus the irradiation intensity of those color components can be determined to a smaller value. When the illuminance is low, compared to when the illuminance is high, the drawing pattern is less likely to become difficult to see even with less light, so by further reducing the irradiation intensity of those color components and thus reducing the light, it is possible to suppress power consumption while preventing the drawing pattern drawn by the irradiated light from becoming difficult to see. Also, when the illuminance is high, compared to when the illuminance is low, the intensity threshold can be reduced, making it easier to set the reflection intensity of color components with relatively low reflection intensity above the intensity threshold, and thus the irradiation intensity of those color components can be determined to a larger value. When the illuminance is high, compared to when the illuminance is low, the drawing pattern becomes difficult to see with less light, so by further increasing the irradiation intensity of those color components and thus increasing the light, it is possible to prevent the drawing pattern drawn by the irradiated light from becoming difficult to see.

[0095] (Other Embodiments, etc.) It should be noted that combining, modifying, or omitting each embodiment as appropriate is also within the scope of the technical concept shown in the embodiments.

[0096] For example, the drawing control device 1a according to Embodiment 2 may further include a modification unit 16b. Also, the drawing control device 1b according to Embodiment 3 may further include a control unit 15a.

[0097] 1, 1a, 1b Drawing control device, 2 Camera, 3 Illumination device, 4a Illuminance sensor, 5a Lighting fixture, 10 Color information acquisition unit, 11 Analysis unit, 12 Drawing pattern determination unit, 13, 13a Illumination intensity determination unit, 14a Illuminance information acquisition unit, 15a Control unit, 16b Modification unit, 100, 100a, 100b, 100c Road surface, 101a, 101b, 102a, 102b Area, 200, 200a, 200b, 200c Drawing pattern, 201c Frame part, 202c Part

Claims

1. A drawing control device comprising: a drawing pattern determination unit that determines a drawing pattern to be drawn on a road surface; a color information acquisition unit that acquires color information indicating the color of the road surface detected by a detector that detects the color of the road surface; an analysis unit that analyzes the reflection intensity of each of a plurality of color components on the road surface based on the color information acquired by the color information acquisition unit; and an irradiation intensity determination unit that determines the irradiation intensity of each of the plurality of color components included in the irradiation light that is irradiated onto the road surface to draw the drawing pattern based on the analysis results of the analysis unit, wherein the irradiation intensity determination unit determines the irradiation intensity of each of the plurality of color components included in the irradiation light such that the irradiation intensity of at least one of the plurality of color components whose reflection intensity is equal to or greater than a predetermined intensity threshold is higher than the irradiation intensity of the color component whose reflection intensity is less than the intensity threshold.

2. The drawing control device according to claim 1, characterized in that the intensity threshold is set to a predetermined ratio with respect to the reflectance of the color component having the highest reflectance among the plurality of color components.

3. The drawing control device according to claim 1, characterized in that the irradiation intensity determination unit determines the irradiation intensity of each of the plurality of color components included in the light used to draw a frame portion provided along the edge of the drawing pattern, such that the irradiation intensity of at least one color component whose reflected intensity is equal to or greater than the intensity threshold is higher than the irradiation intensity of the color component whose reflected intensity is less than the intensity threshold.

4. The drawing control device according to claim 1, wherein, when the road surface has a plurality of colors, if there is a color component among the plurality of color components in which the reflection intensity is equal to or greater than the intensity threshold in any region of the plurality of colors, the irradiation intensity of each of the plurality of color components included in the irradiation light is determined such that the irradiation intensity of the color component is the highest among the plurality of color components.

5. The drawing control device according to claim 1, wherein, when the road surface has a plurality of colors, the irradiation intensity determination unit determines the irradiation intensity of each of the plurality of color components included in the irradiation light such that, for each region of the plurality of colors, the irradiation intensity of at least one color component whose reflection intensity in that region is equal to or greater than the intensity threshold is higher than the irradiation intensity of the color component whose reflection intensity in that region is less than the intensity threshold.

6. The drawing control device according to claim 5, wherein the irradiation intensity determination unit determines the irradiation intensity of each of the plurality of color components contained in the irradiation light such that, when the color of the irradiation light differs between one of two adjacent regions, the color changes in a gradient manner from the color irradiated to the one region to the color irradiated to the other region in the portion including the boundary between the two regions.

7. The drawing control device according to claim 1, comprising: an illuminance information acquisition unit that acquires illuminance information indicating the illuminance measured by a measuring instrument for measuring the illuminance of the road surface; and a control unit that, when the illuminance indicated by the illuminance information acquired by the illuminance information acquisition unit is less than a predetermined illuminance threshold, instructs a luminaire to irradiate the road surface with white light for a period shorter than the period during which a person can perceive white light, and outputs a synchronization signal to the color information acquisition unit that is synchronized with the irradiation of the white light by the luminaire, wherein the color information acquisition unit acquires color information indicating the color of the road surface detected by the detector when the luminaire irradiates the road surface with white light, based on the synchronization signal.

8. The drawing control device according to claim 1, comprising: an illuminance information acquisition unit that acquires illuminance information indicating the illuminance measured by a measuring instrument for measuring the illuminance of the road surface; and a modification unit that changes the intensity threshold based on the illuminance information acquired by the illuminance information acquisition unit such that the intensity threshold is larger when the illuminance is low compared to when the illuminance is high.

Images