Patent ID: 12208727

DETAILED DESCRIPTION

A road-surface rendered image rendered on the road surface as a result of projecting light from the vehicle is not limited to an image that can be visually recognized easily by the driver who drives the vehicle.

For example, when the road surface is to totally reflect light, the light projected from the vehicle for the road-surface rendering is mostly reflected toward, for example, an oncoming vehicle, thus resulting in a reduced quantity of light returning toward the vehicle that has projected the light. In this case, the road-surface rendered image viewed by the driver who drives the vehicle that has projected the light may possibly be a pale image that is difficult to visually recognize.

It is demanded that the road-surface rendered image rendered on the road surface be visually recognizable easily by, for example, the driver who drives the vehicle performing the road-surface rendering even when the headlamp device of the vehicle is turned on. The light used for the road-surface rendering is to have higher brightness than the headlamp device.

On the other hand, for example, when the road surface is to totally reflect light to cause intense regular reflection to occur, there is a concern that a driver who drives an oncoming vehicle or a pedestrian walking toward the vehicle may be irradiated with light more intense than the light from the headlamp via the road surface. Such intense reflection may also possibly occur partially in the road-surface rendered image.

It is desirable that the road-surface rendering from the vehicle be improved.

In the following, some embodiments of the disclosure are described in detail with reference to the accompanying drawings. Note that the following description is directed to illustrative examples of the disclosure and not to be construed as limiting to the disclosure. Factors including, without limitation, numerical values, shapes, materials, components, positions of the components, and how the components are coupled to each other are illustrative only and not to be construed as limiting to the disclosure. Further, elements in the following example embodiments which are not recited in a most-generic independent claim of the disclosure are optional and may be provided on an as-needed basis. The drawings are schematic and are not intended to be drawn to scale. Throughout the present specification and the drawings, elements having substantially the same function and configuration are denoted with the same numerals to avoid any redundant description.

First Embodiment

FIG.1illustrates an example of a traveling state of a vehicle1such as an automobile according to a first embodiment of the disclosure.

FIG.1illustrates the vehicle1traveling on one of lanes of a two-lane road. The automobile is an example of the vehicle1. Other examples of the vehicle1include a bus, a truck, a motorcycle, and a personal mobility device. The vehicle1may be capable traveling based on autonomous driving including driving assistance.

An oncoming vehicle2is traveling on the opposite lane of the road. A pedestrian3is present on a road shoulder.

In such a travel environment, a driver who drives the vehicle1controls the vehicle1without causing the vehicle1to deviate from the road lane while paying attention to what is ahead in the traveling direction of the vehicle1.

When the travel environment is dark, the vehicle1turns on the headlamp. InFIG.1, the irradiation range of the headlamp in a low beam mode and the irradiation range of the headlamp in a high beam mode are indicated with dashed lines.

With regard to such an vehicle1, rendering of patterns by radiating visible light onto the road surface from the vehicle1is being researched and developed.

For example,FIG.1illustrates a road-surface rendered image11based on a simple pattern mimicking a road sign, lane boundary lines12extending along the left and right sides of the lane of the vehicle1, and a road-shoulder boundary line13rendered alongside the road shoulder of the vehicle1. The road-surface rendered image11is rendered in front of the vehicle1in the traveling direction for the driver who drives the vehicle1. The lane boundary lines12and the road-shoulder boundary line13are rendered toward the pedestrian3on the road shoulder and toward the oncoming vehicle2.

The right side ofFIG.1illustrates multiple light projection patterns60each serving as a basis for the road-surface rendered image11. In this case, a light projection pattern61for a left-turn indication, a light projection pattern62for a speed-limit indication, a light projection pattern63for indicating a stop position, a light projection pattern64for a no-crossing indication, a light projection pattern65for a right-turn indication, and a histogram-based light projection pattern66for snowy or frozen road warning. The vehicle1may select any of the multiple light projection patterns60in accordance with the traveling state and the travel environment and may project light corresponding to the light projection pattern.

By rendering a pattern, such as the road-surface rendered image11, on the road surface, the vehicle1can provide travel-related information about the vehicle1to, for example, the driver via the road surface.

However, even when light is projected from the vehicle1to render the road-surface rendered image11on the road surface in this manner, the road-surface rendered image11is not always visually recognizable easily by, for example, the driver who drives the vehicle1.

For example, when the road surface is to totally reflect light, the light projected from the vehicle1for the road-surface rendering is mostly reflected toward, for example, an oncoming vehicle, thus resulting in a reduced quantity of light returning toward the vehicle1that has projected the light. In this case, even when road-surface rendering is executed, the road-surface rendered image viewed by the driver who drives the vehicle1that has projected the light may possibly be a pale image that is difficult to visually recognize.

Furthermore, in a situation where the headlamp device of the vehicle1is turned on, it is demanded that the road-surface rendered image11be visually recognizable easily by, for example, the driver who drives the vehicle1performing the road-surface rendering. In this case, the light used for the road-surface rendering is to have higher brightness than the headlamp device.

On the other hand, if the road surface is to totally reflect light to cause, for example, intense regular reflection to occur, the driver who drives the oncoming vehicle2and the pedestrian3walking toward the vehicle1may be irradiated with intense light via the road surface. The light for the road-surface rendering is totally reflected intensely by the road surface due to, for example, a puddle4on the road surface. Even when the intense reflection is in a part of the road-surface rendered image11, there is a concern that the driver who drives the oncoming vehicle2may be irradiated with light that is more intense than the light from the headlamp.

Accordingly, it is desirable that the road-surface rendering function of the vehicle1be improved.

FIG.2illustrates a control system20provided in the vehicle1inFIG.1.

The control system20of the vehicle1inFIG.2has multiple controllers and a vehicle network26coupled thereto.

The vehicle network26may be a wired communication network compliant with, for example, a controller area network (CAN) or a local interconnect network (LIN) for the vehicle1. The vehicle network26may be a communication network, such as a local area network (LAN), or a combination of the above. The vehicle network26may partially include a wireless communication network. The aforementioned devices coupled to the vehicle network26can exchange information with one another via the vehicle network26.

FIG.2also illustrates a rendering controller21, a headlamp controller22, an operation controller23, a detection controller24, and a communication controller25as examples of the multiple controllers. The vehicle network26may also be coupled to controllers other than the above, such as a travel controller and an air-conditioning controller. Each controller illustrated inFIG.2may be split into multiple units and be coupled to the vehicle network26.

The headlamp controller22is coupled to a right headlamp module31and a left headlamp module32that are provided at the front end of the vehicle1. The right headlamp module31and the left headlamp module32are headlamp members that project light forward of the vehicle1.

As will be described later, the right headlamp module31and the left headlamp module32according to this embodiment each have a light projection module53for road-surface rendering. In this embodiment, the light projection module53of the right headlamp module31and the light projection module53of the left headlamp module32serve as light projection members capable of projecting light for road-surface rendering at least toward the road surface ahead of the vehicle1. That is, the light projection member(s) may include a light source.

The headlamp controller22controls the on mode of the right headlamp module31and the on mode of the left headlamp module32in accordance with information acquired via the vehicle network26. Such information includes operational information about a lamp control lever (not illustrated) and information about a detection value of a light quantity sensor for an automatic light (not illustrated). Normally, the lamp control lever can be set in any of operational modes including a low beam mode, a high beam mode, and an off mode.

The headlamp controller22may output the information about the on mode of the right headlamp module31and the on mode of the left headlamp module32to another controller via the vehicle network26.

The operation controller23is coupled to other operational members to be operated by an occupant, such as the driver.FIG.2illustrates a wiper control lever33as an operational member. The wiper control lever33is used for controlling the operation of a wiper device (not illustrated) for wiping the outer surface of the windshield of the vehicle1. Normally, the wiper control lever33can be set in any of operational modes including an intermittent driving mode, a continuous driving mode, a high-speed continuous driving mode, and a stop mode.

The detection controller24may output the information about the operational modes of the various operational members, such as the wiper control lever33, to another controller via the vehicle network26.

The detection controller24is coupled to various detection members for detecting, for example, the traveling state and the travel environment of the vehicle1.FIG.2illustrates a rain sensor34, a vehicle-exterior camera35, and a global navigation satellite system (GNSS) receiver36as the detection members.

The detection controller24may output, for example, detection information of the rain sensor34to another controller via the vehicle network26.

The rain sensor34is provided on the outer surface of the windshield of the vehicle1and can detect rain and the amount of rainfall based on a change in an electrified state according to wetness caused by raindrops on the rain sensor34.

As illustrated inFIG.1, the vehicle-exterior camera35is provided facing forward in a vehicle cabin located within the windshield of the vehicle1. The vehicle-exterior camera35can capture an image forward of the vehicle1in the traveling direction thereof. The vehicle-exterior camera35may include multiple vehicle-exterior cameras provided in the vehicle1. The multiple vehicle-exterior cameras35may capture images of the environment surrounding the vehicle1in a split fashion. Alternatively, the vehicle-exterior camera35may be a 360°camera or a stereo camera.

The captured image obtained by the vehicle-exterior camera35may include, as a detection image, an image rendered on the road surface in accordance with light projection.

In addition to the vehicle-exterior camera35, other devices that detect the environment surrounding the vehicle1include a Lidar and a laser. Similar to the captured image obtained by the vehicle-exterior camera35, detection information obtained by the Lidar and the laser can be used as information about the environment surrounding the vehicle1.

The vehicle-exterior camera35, the Lidar, and the laser provided in the vehicle1may serve as detection devices capable of detecting the road surface onto which the light projection members project light for road-surface rendering.

The GNSS receiver36receives radio waves from multiple GNSS satellites and detects positional information and time information about the vehicle1provided with the GNSS receiver36.

The communication controller25is coupled to a communication device37. The communication device37exchanges information with a server via, for example, a base station (not illustrated). The base station may be, for example, a 5G base station, an advanced driver-assistance system (ADAS) base station, or an intelligent transport system (ITS) base station. A 5G base station may be capable of implementing a server function. The communication device37may directly communicate with, for example, another vehicle1by vehicle-to-X (V2X) communication.

The communication controller25may transmit information acquired from the vehicle network26from the communication device37to the base station or the server, or may output information received by the communication device37from the base station or the server to the vehicle network26.

The rendering controller21has a memory41, a timer42, a communication port43, an input-output port45, a central processing unit (CPU)44, and an internal bus46coupled to these units. Each controller provided in the control system20may basically have the same structure as the rendering controller21.

The input-output port45is coupled to the right headlamp module31and the left headlamp module32.

The communication port43is coupled to the vehicle network26. The communication port43acquires information from the vehicle network26and outputs information output by the rendering controller21to the vehicle network26.

The timer42measures a time period or a time point. The time point measured by the timer42may be corrected in accordance with a time point obtained by the GNSS receiver36.

The memory41may include, for example, a semiconductor memory, a hard disk drive (HDD), and a random access memory (RAM). The HDD is a nonvolatile memory. The RAM is a volatile memory. The memory41stores, as data, a program to be executed by the CPU44and various kinds of information to be used during the execution of the program. For example, the memory41stores data of the multiple light projection patterns60illustrated inFIG.1.

The CPU44loads and executes the program stored in the memory41. Accordingly, the CPU44serves as a control unit of the rendering controller21. In this embodiment, the CPU44serves as a control unit that controls the light projection for the road-surface rendering by the light projection members.

The CPU44serving as a control unit controls the operation of the rendering controller21. Furthermore, the CPU44serving as a control unit outputs signals to the right headlamp module31and the left headlamp module32via the communication port43. Accordingly, the CPU44serving as a control unit controls the light projection modules53for road-surface rendering provided in the right headlamp module31and the left headlamp module32. The right headlamp module31and the left headlamp module32emit light based on a light projection pattern for road-surface rendering. For example, as illustrated inFIG.1, the road-surface rendered image11corresponding to the light projection pattern may be rendered on the road surface.

FIG.3schematically illustrates the structure and the disposition of the right headlamp module31and the left headlamp module32at the front end of the vehicle1inFIG.1.

FIG.3illustrates the front end of the vehicle1.

The right end at the front end of the vehicle1is provided with the right headlamp module31. The right headlamp module31has multiple low-beam light-emitting diodes (LEDs)51, multiple high-beam LEDs52, and a micro-electro-mechanical system (MEMS) light projection module53.

The left end at the front end of the vehicle1is provided with the left headlamp module32. The left headlamp module32has multiple low-beam LEDs51, multiple high-beam LEDs52, and a MEMS light projection module53.

The light projection modules53may alternatively be, for example, digital micro-mirror device (DMD) light projection modules.

For example, each MEMS light projection module53may be configured to project light by reflecting three primary colors of light by using a MEMS element. The reflection mode of the MEMS element may be controlled in accordance with an image signal.

The right headlamp module31or the left headlamp module32may be capable of rendering an image other than that of the MEMS light projection module53on the road surface.

Each MEMS light projection module53may be capable of projecting light within the irradiation range of all of the multiple low-beam LEDs51and the multiple high-beam LEDs52, as well as projecting light outside the irradiation range. The rendering pattern for the no-crossing indication for the pedestrian3inFIG.1is partially outside the irradiation range of all of the multiple low-beam LEDs51and the multiple high-beam LEDs52.

InFIG.3, the MEMS light projection module53of the right headlamp module31projects light, so that a road-surface rendered image11for a right-turn indication corresponding to the right-turn-indication light projection pattern65is rendered on the road surface.

Furthermore, the MEMS light projection module53of the left headlamp module32projects light, so that a road-surface rendered image11for a left-turn indication corresponding to the left-turn-indication light projection pattern61is rendered on the road surface.

The MEMS light projection module53of the right headlamp module31and the MEMS light projection module53of the left headlamp module32may operate in cooperation with each other to render a single large road-surface rendered image11on the road surface, as illustrated inFIG.1.

The CPU44serving as a control unit controls the MEMS light projection module53of the right headlamp module31and the MEMS light projection module53of the left headlamp module32in accordance with a light projection pattern, so as to be capable of rendering a road-surface rendered image11corresponding to the light projection pattern on the road surface.

Accordingly, the MEMS light projection module53of the right headlamp module31and the MEMS light projection module53of the left headlamp module32can serve as light projection members that project the road-surface rendered image11in accordance with the light projection pattern.

As illustrated inFIG.1, the MEMS light projection module53of the right headlamp module31may project light for road-surface rendering such as to exclude the front end with respect to the high-beam light projection range on the road surface by the right headlamp module31.

Moreover, as illustrated inFIG.1, the MEMS light projection module53of the left headlamp module32may project light for road-surface rendering such as to exclude the front end with respect to the high-beam light projection range on the road surface by the left headlamp module32.

FIG.4is a flowchart of road-surface rendering control according to the first embodiment executed by the rendering controller21inFIG.2.

The CPU44serving as a control unit of the rendering controller21repeatedly executes the road-surface rendering control inFIG.4.

When a rendering control function is implemented in the headlamp controller22in the control system20, the CPU44of the headlamp controller22may serve as a control unit that repeatedly executes the road-surface rendering control inFIG.4.

In step ST1, the CPU44that controls light projection for road-surface rendering determines whether road-surface rendering is to be performed. A request for road-surface rendering may be generated by each controller in the control system20. For example, when the headlamp is to be turned on, the headlamp controller22may generate information for requesting road-surface rendering and output the information to the rendering controller21via the vehicle network26. When there is a request for road-surface rendering, the CPU44causes the process to proceed to step ST2. When there is no request for road-surface rendering, the CPU44ends the control.

In step ST2, the CPU44selects a light projection pattern to be used for the road-surface rendering from the multiple light projection patterns60stored in the memory41. The CPU44may select multiple light projection patterns or may select one light projection pattern.

In step ST3, the CPU44controls the light projection module53of the right headlamp module31and the light projection module53of the left headlamp module32to irradiate the road surface with light according to the selected light projection pattern. Accordingly, a road-surface rendered image11corresponding to the light projection pattern is rendered on the road surface.

In step ST4, the CPU44acquires a captured image obtained by the vehicle-exterior camera35. The captured image obtained by the vehicle-exterior camera35may be a captured image of the road surface on which the road-surface rendered image11output in step ST3is rendered. In this case, the vehicle-exterior camera35serves as a detection device that detects a detection image.

In step ST5, the CPU44compares the road-surface rendered image11in the captured image obtained by the vehicle-exterior camera35with the selected light projection pattern so as to start determining whether the road-surface rendering is adequate.

In this case, the CPU44may clip the detection image including the road-surface rendered image11from the captured image and compare the detection image with the selected light projection pattern. The position and the range of the road-surface rendered image11in the captured image can be identified based on the light projection direction and the light projection range used in the control in step ST3. Alternatively, the CPU44may generate a detection image directly facing the road-surface rendered image11based on, for example, an angle of the extending direction of the road surface with reference to the vehicle1.

Then, in order to determine the overall agreement between the detection image and the selected light projection pattern, the CPU44first determines an inconsistency in the rendered shape.

For example, when light is projected onto an uneven or irregular road surface, the road-surface rendered image11and the captured detection image thereof include distortion according to the unevenness or the irregularities. In this case, there is a possibility that the driver who drives the vehicle1cannot comprehend the road-surface rendered image11since the driver is not able to ascertain the overall image even if the driver visually recognizes the road-surface rendered image11rendered on the road surface.

In addition, for example, when there is a hole in the road surface, the road-surface rendered image11and the captured detection image thereof include distortion according to the hole. In this case, there is a possibility that the driver who drives the vehicle1cannot comprehend the road-surface rendered image11since the driver is not able to ascertain the overall image even if the driver visually recognizes the road-surface rendered image11rendered on the road surface.

When the detection image includes any of these defects, the CPU44may determine that there is no overall agreement between the detection image and the selected light projection pattern. In this case, the CPU44causes the process to proceed to step ST8.

When the detection image does not include any of these defects, the CPU44may determine that there is overall agreement between the detection image and the selected light projection pattern. In this case, the CPU44causes the process to proceed to step ST6for a further evaluation of the detection image.

In step ST6, the CPU44determines whether there is an overall light-quantity insufficiency with respect to the detection image.

For example, when the road surface reflects light easily, the quantity of light returning to the vehicle1decreases, possibly causing the overall brightness (light quantity) of the detection image to decrease.

The CPU44may determine whether an average brightness value of all the pixels constituting the detection image is larger than or equal to a threshold value.

In addition, for example, the CPU44may compare an average brightness value of some of the pixels constituting the detection image with a first threshold value.

The first threshold value may be a brightness value at which the driver who drives the vehicle1can conceivably visually recognize the road-surface rendered image11properly. For example, the first threshold value may change in accordance with the travel environment of the vehicle1, such as between daytime and nighttime. Furthermore, the first threshold value may change in accordance with the on/off mode of the headlamp or the lighting mode thereof.

When the values to be compared with respect to the detection image include a value smaller than or equal to the first threshold value, the CPU44determines that there is an overall light-quantity insufficiency in the detection image and causes the process to proceed to step ST8.

When the values to be compared with respect to the detection image do not include a value smaller than or equal to the first threshold value, the CPU44determines that there is no overall light-quantity insufficiency in the detection image and causes the process to proceed to step ST7for a further evaluation of the detection image.

In step ST7, the CPU44determines whether there is an insufficient reflection area in the detection image of the vehicle1. For example, an insufficient reflection area refers to an area where reflection light returning from the road-surface rendered image11toward the driver who drives the vehicle1is insufficient when the road-surface rendered image11is oriented toward the driver who drives the vehicle1. If there is an insufficient reflection area in the road-surface rendered image11, the brightness in the insufficient reflection area may also be lower than other areas in the detection image in the captured image obtained by the vehicle-exterior camera35.

For example, when the road-surface rendered image11partially overlaps the puddle4, as illustrated inFIG.1, the road-surface rendered image11may have an insufficient reflection area occurring in the overlapping area. In addition to the puddle4, the road surface may also have snow, a maintenance hole, or the like.

The CPU44may determine whether the brightness value of each of the pixels constituting the detection image is smaller than or equal to a second threshold value.

For example, the second threshold value may be a brightness value corresponding to a difference for determining insufficient reflection with reference to an average brightness value of all or some of the pixels constituting the detection image.

Furthermore, with regard to pixels with brightness values smaller than or equal to the second threshold value, the CPU44may perform further determination with respect to the percentage of the number of pixels relative to all of the pixels constituting the detection image. The determination result indicates the aforementioned area when the percentage of the number of pixels is not 100%.

When pixels with brightness values smaller than or equal to the second threshold value are included at a predetermined percentage not equal to 100% as an area in the detection image, the CPU44determines that the detection image has an insufficient reflection area and causes the process to proceed to step ST8.

When pixels with brightness values smaller than or equal to the second threshold value are included at below the predetermined percentage or higher in the detection image, the CPU44determines that there is no insufficient reflection area in the detection image and causes the process to proceed to step ST9.

In step ST8, the CPU44discontinues the road-surface rendering. The CPU44stops the road-surface irradiation started in step ST3. Accordingly, the rendering of the road-surface rendered image11on the road surface is discontinued. Subsequently, the CPU44ends the control.

In contrast, when the process is not to proceed to step ST8, that is, when the process is to proceed from step ST7to step ST9, the CPU44continues with the road-surface irradiation started in step ST3.

In step ST9, the CPU44determines whether the road-surface rendering is to be terminated. The CPU44may determine that the road-surface rendering is to be terminated when, for example, there is no request for road-surface rendering. In this case, the CPU44ends the control.

For example, when there is a request remaining for road-surface rendering, the CPU44determines that the road-surface rendering is not to be terminated, and causes the process to return to step ST2. In this case, the CPU44repeats the process from step ST2to step ST9so as to continue with the road-surface rendering.

Accordingly, the CPU44at least determines insufficient reflection in the road-surface rendered image11based on the road-surface detection (i.e., the captured image) by the vehicle-exterior camera35serving as a detection device, so as to be capable of controlling the light projection for the road-surface rendering. When an insufficient reflection area has occurred in the detection image at the predetermined percentage or higher, control can be performed for stopping the light projection for the road-surface rendering from the light projection modules53.

Furthermore, with regard to the detection image of the road-surface rendered image11that is not entirely inconsistent with the light projection pattern, the CPU44determines overall insufficient reflection with respect to the brightness of the detection image and determines a brightness difference at least in multiple areas of the detection image, so as to be capable of determining whether there is an insufficient reflection area. When there is an insufficient reflection area in the detection image, the CPU44can perform suppression by discontinuing the light projection for the road-surface rendering.

Alternatively, in step ST8, the CPU44may reduce the light quantity instead of stopping the light projection.

FIG.5illustrates a captured image70obtained by the vehicle-exterior camera35inFIG.2.

The captured image70inFIG.5is captured by the vehicle-exterior camera35of the vehicle1in the traveling state inFIG.1.

Therefore, the captured image70inFIG.5includes an image71of the oncoming vehicle2, an image72of the pedestrian3, and a detection image73of the road-surface rendered image11, together with the road on which the vehicle1is traveling.

The following description with reference toFIG.6toFIG.9relates to an example of the detection image73including an insufficient reflection area where the quantity of light returning toward the driver who drives the vehicle1is insufficient.

FIG.6illustrates a first example of the detection image73, in the road-surface rendering, included in the captured image70.

FIG.7illustrates a second example of the detection image73, in the road-surface rendering, included in the captured image70.

The detection image73in the road-surface rendering inFIG.6and the detection image73in the road-surface rendering inFIG.7each relate to the road-surface rendered image11based on the speed-limit light projection pattern62.

In the detection image73according to the first example inFIG.6, the upper right area, the upper left area, and the lower left area have image deficiencies74occurring therein as a result of intense reflection occurring due to the puddle4, such that the quantity of light toward the driver who drives the vehicle1is insufficient. However, a main area75in the middle of the detection image73displaying a speed-limit value is not deficient.

In this case, in step ST7inFIG.4, the CPU44according to this embodiment may determine that the detection image73includes an insufficient reflection area at the predetermined percentage or higher, and may discontinue the rendering in step ST8.

In the detection image73according to the second example inFIG.7, a large area from the right side toward the middle has an image deficiency74occurring therein as a result of intense reflection occurring due to the puddle4, such that the quantity of light toward the driver who drives the vehicle1is insufficient. In this case, the main area75in the middle of the detection image73displaying the speed-limit value is also deficient.

In this case, in step ST7inFIG.4, the CPU44according to this embodiment may determine that the detection image73includes an insufficient reflection area at the predetermined percentage or higher, and may discontinue the rendering in step ST8.

FIG.8illustrates a third example of the detection image73, in the road-surface rendering, included in the captured image70.

FIG.9illustrates a fourth example of the detection image73, in the road-surface rendering, included in the captured image70.

The detection image73in the road-surface rendering inFIG.8and the detection image73in the road-surface rendering inFIG.9each relate to the road-surface rendered image11based on the left-turn-indication light projection pattern61.

In the detection image73according to the third example inFIG.8, a large area from the upper left corner toward the middle has an image deficiency74occurring therein as a result of intense reflection occurring due to the puddle4, such that the quantity of light toward the driver who drives the vehicle1is insufficient. In this case, in the main area75in the middle of the detection image73, the tip area of an arrow indicating the traveling direction is deficient.

In this case, in step ST7inFIG.4, the CPU44according to this embodiment may determine that the detection image73includes an insufficient reflection area at the predetermined percentage or higher, and may discontinue the rendering in step ST8.

In the detection image73according to the fourth example inFIG.9, the upper area, the right area, and the lower area have image deficiencies74occurring therein as a result of intense reflection occurring due to the puddle4, such that the quantity of light toward the driver who drives the vehicle1is insufficient. However, in the main area75in the middle of the detection image73, the tip area of the arrow indicating the traveling direction is not deficient.

In this case, in step ST7inFIG.4, the CPU44according to this embodiment may determine that the detection image73includes an insufficient reflection area at the predetermined percentage or higher, and may discontinue the rendering in step ST8.

Accordingly, in this embodiment, the CPU44that controls the light projection for the road-surface rendering at least determines insufficient reflection in the road-surface rendering based on the road-surface detection (i.e., the captured image70) by the vehicle-exterior camera35serving as a detection device provided in the vehicle1. Then, the CPU44controls the light projection for the road-surface rendering based on, for example, the insufficient reflection in the detection image73. Accordingly, in this embodiment, for example, supposing that the road-surface rendered image11rendered on the road surface is entirely pale and difficult to visually recognize from the driver who drives the vehicle1performing the road-surface rendering, control can be performed to suppress the light projection for the road-surface rendering by discontinuing the rendering. This embodiment can prevent continuous execution of road-surface rendering where sufficient visibility is not obtainable. The driver who drives the oncoming vehicle2and the pedestrian3walking toward the vehicle1can be prevented from continuously receiving intense light via the road surface as a result of total reflection occurring on the road surface.

In particular, in this embodiment, the vehicle-exterior camera35can detect the detection image73of the road-surface rendered image11projected on the road surface by image-capturing. The CPU44that controls the light projection for the road-surface rendering determines whether the detection image73detected by the vehicle1has an insufficient reflection area. If an insufficient reflection area has occurred at a predetermined area percentage, the CPU44suppresses the light projection for the road-surface rendering by discontinuing the light projection. Accordingly, in this embodiment, even when the road-surface rendered image11rendered on the road surface is partially difficult to visually recognize from, for example, the driver who drives the vehicle1performing the road-surface rendering, control can be performed by discontinuing the light projection for the road-surface rendering. In this embodiment, even when the road-surface rendered image11rendered on the road surface is partially deficient, continuous execution of the road-surface rendering can be prevented. Furthermore, the driver who drives the oncoming vehicle2and the pedestrian3walking toward the vehicle1can be prevented from continuously receiving intense light via the road surface as a result of intense reflection occurring on the road surface in the deficient area.

Accordingly, in this embodiment, the road-surface rendering from the vehicle1involves suppression to prevent the light projection for the road-surface rendering from being excessive, so that an improvement in the road-surface rendering by the vehicle1can be expected.

Second Embodiment

Next, a road-surface rendering device of the vehicle1according to a second embodiment of the disclosure will be described.

This embodiment relates to an example where rendering can be continuously performed even when a deficiency caused by an insufficient light quantity occurs in the road-surface rendered image11.

The following description mainly relates to differences from the above embodiment.

FIG.10is a flowchart of road-surface rendering control according to the second embodiment executed by the rendering controller21inFIG.2.

The CPU44serving as a control unit of the rendering controller21repeatedly executes the road-surface rendering control inFIG.10.

When the rendering control function is implemented in the headlamp controller22in the control system20, the CPU of the headlamp controller22may repeatedly execute the road-surface rendering control inFIG.10.

Step ST1to step ST9are similar to those in the above embodiment.

However, if it is determined in step ST5that the detection image73does not entirely match the selected light projection pattern, the CPU44causes the process to proceed to step ST11.

If it is determined in step ST6that there is an overall light-quantity insufficiency in the detection image73, the CPU44causes the process to proceed to step ST11.

If it is determined in step ST7that there is an insufficient reflection area with respect to the detection image73in the vehicle1, the CPU44causes the process to proceed to step ST11.

In step ST11, the CPU44further determines whether the rendering is adequate based on the main area75of the detection image73.

Then, for example, when a deficiency caused by an insufficient light quantity has not occurred in the main area75of the detection image73corresponding to the main area75of the light projection pattern even if there is a large deficiency caused by the puddle4in the entire detection image73, the CPU44may determine that the rendering is adequate. In this case, the CPU44causes the process to proceed to step ST12.

In contrast, when the main area75of the detection image73corresponding to the main area75of the light projection pattern has a deficiency caused by an insufficient light quantity, it may be determined that the rendering is inadequate. In this case, the CPU44causes the process to proceed to step ST8. In this case, the CPU44discontinues the road-surface rendering and ends the control.

In step ST12, the CPU44partially suppresses the light projection with respect to the area with the insufficient light quantity in the detection image73.

In this case, the CPU44performs light reduction to reduce the quantity of projected light with respect to the area with the insufficient light quantity in the detection image73.

In step ST13, the CPU44acquires the latest captured image70obtained by the vehicle-exterior camera35and determines whether the reduced quantity for light the area with the insufficient light quantity in the detection image73is enough.

If the reduced quantity of light is not enough, the CPU44causes the process to return to step ST12. The CPU44repeats the process from step ST12to step ST13until the reduced quantity of light becomes enough.

When the reduced quantity of light becomes enough, the CPU44ends the control.

Accordingly, in this embodiment, when the detection image73detected by the vehicle-exterior camera35serving as a detection device provided in the vehicle1has an insufficient reflection area, the CPU44that controls the light projection for the road-surface rendering determines the relationship that the insufficient reflection area has with the main area of the light projection pattern. Then, if the main area75of the detection image73corresponding to the main area of the light projection pattern is rendered without being an insufficient reflection area, the quantity of projected light with respect to the area with the insufficient reflection in the detection image73can be reduced and suppressed.

For example, in the detection image73according to the aforementioned first example inFIG.6, the main area75in the middle of the detection image73displaying the speed-limit value is not deficient.

In this case, the CPU44according to this embodiment may determine in step ST11inFIG.10that the rendering is adequate since the main area75is not deficient, and may execute the light reduction process from step ST12to step ST13with respect to the area with the insufficient reflection caused by the puddle4.

In contrast, in the detection image73according to the second example inFIG.7, the main area75in the middle of the detection image73displaying the speed-limit value is deficient.

In this case, the CPU44according to this embodiment may determine in step ST11inFIG.10that the rendering is inadequate since the main area75is deficient, and may discontinue the rendering in step ST8.

In the detection image73according to the third example inFIG.8, the tip area of the arrow indicating the traveling direction in the main area75in the middle of the detection image73is deficient.

In this case, the CPU44according to this embodiment may determine in step ST11inFIG.10that the rendering is inadequate since the main area75is deficient, and may discontinue the rendering in step ST8.

In contrast, in the detection image73according to the fourth example inFIG.9, the tip area of the arrow indicating the traveling direction in the main area75in the middle of the detection image73is not deficient.

In this case, the CPU44according to this embodiment may determine in step ST11inFIG.10that the rendering is adequate since the main area75is not deficient, and may execute the light reduction process from step ST12to step ST13with respect to the area with the insufficient reflection caused by the puddle4.

Third Embodiment

Next, a road-surface rendering device of the vehicle1according to a third embodiment of the disclosure will be described.

This embodiment relates to an example involving controlling the road-surface rendering by predicting an occurrence of a deficiency caused by an insufficient light quantity in the road-surface rendered image11.

The following description mainly relates to differences from the above embodiments.

FIG.11is a flowchart of road-surface rendering control according to the third embodiment executed by the rendering controller21inFIG.2.

The CPU44serving as a control unit of the rendering controller21repeatedly executes the road-surface rendering control inFIG.11.

When the rendering control function is implemented in the headlamp controller22in the control system20, the CPU of the headlamp controller22may repeatedly execute the road-surface rendering control inFIG.11.

Step ST1to step ST9and step ST12are similar to those in the above embodiments.

However, after step ST4, the CPU44causes the process to proceed to step ST21.

In step ST21, the CPU44uses the captured image70acquired in step ST4to predict and determine whether the road-surface rendering is adequate based on a deformation in the road-surface rendered image11when the vehicle1travels.

For example, when the road-surface rendered image11detected as the detection image73travels together with the vehicle1, the CPU44may determine whether the road-surface rendered image11overlaps, for example, a step, a protrusion or recess, or a hole in the road surface.

Then, when the CPU44predicts and determines that the road-surface rendered image11is to deform by overlapping, for example, a step on the road surface, the CPU44causes the process to proceed to step ST24.

If the CPU44predicts and determines that the road-surface rendered image11is not to deform, the CPU44causes the process to proceed to step ST22.

In step ST22, the CPU44uses the captured image70acquired in step ST4to predict and determine whether the road-surface rendering is adequate based on an overall light-quantity insufficiency in the road-surface rendered image11when the vehicle1travels.

For example, when the captured detection image73of the road-surface rendered image11travels together with the vehicle1, the CPU44may determine whether the detection image73entirely overlaps an insufficient reflection area of the road surface. In this case, the CPU44extracts an area where the quantity of reflected light is smaller than those in other areas as an insufficient reflection area of the road surface within the high-beam irradiation range included in the captured image70. Then, the CPU44may determine whether the detection image73entirely overlaps the insufficient reflection area of the road surface based on the relationship between the position and range of the insufficient reflection area with respect to the high beam and the position and range of the detection image73.

Then, when the CPU44predicts and determines that the detection image73entirely overlaps the insufficient reflection area of the road surface, the CPU44causes the process to proceed to step ST24.

If the CPU44predicts and determines that the detection image73does not entirely overlap the insufficient reflection area of the road surface, the CPU44causes the process to proceed to step ST23.

In step ST23, the CPU44uses the captured image70acquired in step ST4to predict and determine whether the road-surface rendering is adequate based on a partial light-quantity insufficiency in the road-surface rendered image11when the vehicle1travels.

For example, when the captured detection image73of the road-surface rendered image11travels together with the vehicle1, the CPU44may determine whether the detection image73partially overlaps the insufficient reflection area of the road surface.

Furthermore, when the main area75of the captured detection image73of the road-surface rendered image11travels together with the vehicle1, the CPU44may determine whether the main area75partially overlaps the insufficient reflection area of the road surface.

Then, when the CPU44predicts and determines that the detection image73partially overlaps the insufficient reflection area of the road surface, the CPU44causes the process to proceed to step ST24.

If the CPU44predicts and determines that the detection image73does not partially overlap the insufficient reflection area of the road surface, the CPU44causes the process to proceed to step ST9. In this case, the CPU44continues with the road-surface rendering.

In step ST24, the CPU44determines whether the road-surface rendered image11starts to pass the insufficient reflection area that has undergone the prediction and determination.

For example, the CPU44can calculate the timing at which the road-surface rendered image11starts to pass the insufficient reflection area of the road surface based on the distance between the road-surface rendered image11and the insufficient reflection area of the road surface and the speed of the vehicle1.

If the calculated timing is not measured by the timer42, the CPU44repeats this process. Then, when the calculated timing is measured by the timer42, the CPU44determines that the road-surface rendered image11is to start passing the insufficient reflection area that has undergone the prediction and determination, and causes the process to proceed to step ST25.

In step ST25, when the road-surface rendered image11passes the insufficient reflection area of the road surface, the CPU44determines whether a deficiency caused by an insufficient light quantity occurs in the main area75of the road-surface rendered image11.

When the CPU44determines that a deficiency caused by an insufficient light quantity occurs in the main area75of the road-surface rendered image11, the CPU44causes the process to proceed to step ST8. In this case, the CPU44discontinues the road-surface rendering and causes the process to proceed to step ST26.

In contrast, if the CPU44determines that a deficiency caused by an insufficient light quantity does not occur in the main area75of the road-surface rendered image11, the CPU44causes the process to proceed to step ST12. In this case, the CPU44performs light reduction with respect to a remaining area76other than the main area75of the road-surface rendered image11. The CPU44may perform the light reduction with respect to an area where a deficiency caused by an insufficient light quantity occurs in the remaining area76of the road-surface rendered image11. Subsequently, the CPU44causes the process to proceed to step ST26.

In step ST26, the CPU44determines whether the road-surface rendered image11completely passes the insufficient reflection area that has undergone the prediction and determination.

For example, the CPU44can calculate the timing at which the road-surface rendered image11completely passes the insufficient reflection area of the road surface based on the distance between the road-surface rendered image11and the insufficient reflection area of the road surface and the speed of the vehicle1.

If the calculated timing is not measured by the timer42, the CPU44repeats this process. Then, when the calculated timing is measured by the timer42, the CPU44determines that the road-surface rendered image11has passed the insufficient reflection area that has undergone the prediction and determination, and causes the process to proceed to step ST27.

In step ST27, the CPU44resumes the road-surface rendering. Similar to step ST3, the CPU44controls the light projection module53of the right headlamp module31and the light projection module53of the left headlamp module32to irradiate the road surface with light according to the selected light projection pattern. Accordingly, the projection of the road-surface rendered image11corresponding to the light projection pattern resumes on the road surface. Subsequently, the CPU44causes the process to proceed to step ST9.

FIG.12illustrates a change in the road-surface rendering under the road-surface rendering control inFIG.11.

InFIG.12, time elapses from a time point T1toward a time point T3.

The vehicle1travels from right to left in the drawing. In this case, the road-surface rendered image11also moves from right to left in the drawings.

At each time point inFIG.12, the puddle4is illustrated together with the road-surface rendered image11.

At the time point T1, the puddle4exists in the traveling direction of the road-surface rendered image11. In this case, the CPU44performs step ST22or step ST23inFIG.11, and subsequently determines whether the road-surface rendered image11starts to pass the puddle4in step ST24.

Then, at the time point T2, the road-surface rendered image11overlaps the puddle4. In this case, the CPU44performs step ST8or step ST12inFIG.11so as to discontinue the rendering. The road surface is not irradiated with the light for the road-surface rendered image11. The CPU44may execute light reduction for the insufficient reflection area in the rendered image.

Subsequently, at the time point T3, the road-surface rendered image11has passed the puddle4. In this case, the CPU44performs, for example, step ST27inFIG.11so as to resume the rendering. The road surface is irradiated with the light for the road-surface rendered image11.

Accordingly, the CPU44discontinues the road-surface rendering or performs the light reduction during the period in which the road-surface rendered image11overlaps the puddle4on the road surface, and can resume the road-surface rendering after the road-surface rendered image11has passed the puddle4.

Accordingly, in this embodiment, the CPU44at least predicts and determines insufficient reflection in the road-surface rendering based on detection by the vehicle-exterior camera35with respect to the road surface illuminated by the headlamp, so as to be capable of controlling the light projection for the road-surface rendering.

For example, the CPU44determines insufficient reflection with respect to the road surface in the headlamp light projection range located forward in the traveling direction of the vehicle1relative to the road-surface position receiving the light projected for the road-surface rendering, so as to be capable of predicting and determining insufficient reflection in the road-surface rendering.

Although the above embodiments are examples of preferred embodiments of the disclosure, the embodiments of the disclosure are not limited thereto and permit various modifications and alterations so long as they do not depart from the scope of the embodiments of the disclosure.

In the above embodiments, each light projection module53serving as a light projection member is provided in the vehicle1integrally with the headlamp LEDs51and52in the right headlamp module31or the left headlamp module32.

Alternatively, for example, each light projection module53serving as a light projection member may be provided in the vehicle1separately from the right headlamp module31or the left headlamp module32.

Furthermore, the vehicle1may be provided with a single light projection module53or three or more light projection modules53. The single light projection module53or the third light projection module53may be provided at the widthwise center of the front surface of the vehicle1.

In the above embodiments of the disclosure, the control unit that controls the light projection for the road-surface rendering by the light projection member at least determines insufficient reflection in the road-surface rendering in the vehicle based on road-surface detection by the detection device. Then, the control unit performs control to suppress the light projection for the road-surface rendering based on the insufficient reflection in the vehicle. Accordingly, in the embodiments of the disclosure, for example, supposing that an image rendered on the road surface is entirely pale and difficult to visually recognize from a driver who drives the vehicle performing the road-surface rendering, control can be performed to suppress the light projection for the road-surface rendering.

The embodiments of the disclosure can prevent continuous execution of road-surface rendering where sufficient visibility is not obtainable.

If the road surface is to totally reflect light to cause, for example, intense regular reflection to occur, a driver who drives an oncoming vehicle and a pedestrian walking toward the vehicle can expectedly be prevented from being continuously irradiated with intense light from the headlamp via the road surface.

In the embodiments of the disclosure, an improvement in the road-surface rendering from the vehicle can be expected by controlling the light projection for the road-surface rendering.

The control system20illustrated inFIG.2can be implemented by circuitry including at least one semiconductor integrated circuit such as at least one processor (e.g., a central processing unit (CPU)), at least one application specific integrated circuit (ASIC), and/or at least one field programmable gate array (FPGA). At least one processor can be configured, by reading instructions from at least one machine readable tangible medium, to perform all or a part of functions of the control system20including the rendering controller21, the headlamp controller22, the operation controller23, the detection controller24, the communication controller25, and the vehicle network26. Such a medium may take many forms, including, but not limited to, any type of magnetic medium such as a hard disk, any type of optical medium such as a CD and a DVD, any type of semiconductor memory (i.e., semiconductor circuit) such as a volatile memory and a non-volatile memory. The volatile memory may include a DRAM and a SRAM, and the non-volatile memory may include a ROM and a NVRAM. The ASIC is an integrated circuit (IC) customized to perform, and the FPGA is an integrated circuit designed to be configured after manufacturing in order to perform, all or a part of the functions of the modules illustrated inFIG.2.