WO2018091563A1

WO2018091563A1 - A display system for a vehicle, a vehicle and method

Info

Publication number: WO2018091563A1
Application number: PCT/EP2017/079391
Authority: WO
Inventors: Joshua Close; Iosif Todor
Original assignee: Jaguar Land Rover Limited
Priority date: 2016-11-21
Filing date: 2017-11-16
Publication date: 2018-05-24
Also published as: GB2570585B; GB201619639D0; GB2558538A; GB2570585A; GB201902777D0

Abstract

A display system (12) in a vehicle (10) includes a camera (14) for capturing image data, a processing unit (16), a display module (18), and a sensor arrangement (20) which measures at least one parameter relating to an object of interest the vehicle's environment. The image data from the camera (14) is displayed on the display module (18) and the processing unit (16) generates a graphical indication in dependence on the measured value of the parameter which is overlaid on the displayed image in respect of the object of interest in the displayed image. The graphical indication may relate to the distance between the vehicle and the object of interest. Alternatively, the graphical indication may indicate an assed level of risk associated with the object of interest. The system (12) may provide a rear-view display for the vehicle.

Description

A DISPLAY SYSTEM FOR A VEHICLE, A VEHICLE AND METHOD TECHNICAL FIELD

The present disclosure relates to a display system for a vehicle. Aspects of the invention relate to a vehicle display system, a vehicle comprising a display system and a method.

BACKGROUND

It is a standard feature for a road vehicle to include a rear-facing mirror mounted onto the inside surface of the windscreen of the vehicle and angled so as to be able to see out of the rear of the vehicle from a driving position. However, such mirrors suffer a number of drawbacks. Most notably, the driver's view out of the rear of the vehicle through the mirror can be obstructed by people sat in the rear seats of the vehicle or by components of the vehicle itself such as rear headrests or a vehicle pillar, such as the "D" pillar of the vehicle, for example.

To overcome the above issues with mounted rear-view mirrors, it has become known to replace the mirror with a display module which shows an image feed from a camera mounted at the back of the vehicle. This removes any obstructions in the image from people or components within the vehicle itself. Commonly, such displays have been provided within the same module as a standard rear-view mirror and can be used in a "mirror mode" where the module is used as a standard mirror or in a "display mode" where the module is used to display an image feed from the camera. The driver will typically have the ability to switch between the two modes. However, this solution still suffers from a number of drawbacks. Object size varies on a different linear scale with a camera image than it does with a reflective surface, such as the mirror. This means that depth perception is not as easily judged by a driver who is used to using a traditional rear-view mirror when using the "display mode". This is exaggerated by the fact that the camera is placed at the rear of the vehicle, which may be a few meters away from the position of the display module/mirror mounted within the vehicle. The overall result of this effect is that, to a user using such a system, objects less than a certain distance away appear larger in the camera image than in a traditional mirror, whereas objects further than that distance away appear smaller.

It would therefore be advantageous to provide a system which at least partially mitigates these issues. It is an aim of the present invention to address disadvantages associated with such systems.

SUMMARY OF THE INVENTION Aspects and embodiments of the invention provide a display system, a vehicle, and a method as claimed in the appended claims.

According to an aspect of the invention, there is provided a controller for a vehicle display system, the controller comprising:

a first input configured to receive image data from a camera;

an output configured to output image data from the camera to a display module having a display panel configured to show images formed from the image data captured by the camera;

a second input configured to receive data from a sensor arrangement adapted to measure at least one parameter relating to an object of interest exterior to the vehicle; and

a processing unit operable in dependence on data from the at least one sensor to overlay on the image shown on the display module at least one graphical indicator, the processing unit being configured to generate the at least one graphical indicator in dependence on the value of the at least one parameter measured by the sensor arrangement in relation to an object of interest visible in the displayed image.

In this way, the controller is capable of overlaying on images shown on the display module a graphical indicator to assist a user in cognitively evaluating the image data when using the display module. For example, the graphical indicator may assist the user in judging depth perception. This is particularly beneficial where the display module is used as a replacement for, or part of, a rear-view mirror of the vehicle.

The controller may be configured to generate and cause display on the display module of at least one graphical indicator which is related to the distance between a vehicle in which the system is implemented and the object of interest. The controller may be configured to generate and cause display on the display module of at least one graphical indicator which provides a numerical indication of the distance between the vehicle in which the controller is implemented and the object of interest. Alternatively, the controller may be configured to generate and cause display on the display module of at least one graphical indicator which provides a graphical representation of the distance between the vehicle in which the controller is implemented and the object of interest. The graphical representation may, for example, comprise a colour scale. The colour scale may be continuously varying or may vary in discrete steps.

The controller may be configured to generate and cause display on the display module of at least one graphical indicator which is related to the speed and/or trajectory of an object of interest identified in the displayed image relative to a vehicle in which the controller is implemented.

The controller may be configured to assess a level of risk posed by an object of interest and to generate and cause display on the display module of at least one graphical indicator which is indicative of the assessed level of risk. Assessment of the level of risk may be based on the proximity of the object of interest to a vehicle in which the controller is implemented and/or the relative speed of the object of interest to the vehicle and/or the trajectory of the object of interest relative to the vehicle. The graphical indication may, for example, comprise a colour scale indicative of the assessed level of risk. The colour scale may be continuously varying or may vary in discrete steps. For example, in some embodiments the colour scale may comprise a first colour, which may be red, where the assessed level of risk is high. Likewise, the colour scale may comprise a second colour, which may be green, where the level of risk is assed to be low. The colour scale may have a range of different colours each being assigned a different meaning.

Providing graphical indicators which inform the user of assessed levels of risk allow the user to interpret the displayed image quickly and intuitively without having to read and interpret numerical data regarding a measured parameter. This may be particularly suitable where the image is being displayed in a vehicle that is travelling forwardly at speed and where the user cannot take their eyes off the road to concentrate on the displayed image for any length of time.

The controller may be configured in use to generate and cause display of different types of graphic indicator on the display module in dependence on the operating mode of the vehicle in which the controller is implemented. The operating mode of the vehicle may refer to the vehicle operating in a forward gear or a reverse gear. For example, the controller may be configured to generate and cause display of graphical indicators which provide numerical data when the vehicle is being driven in reverse and graphical indicators which are indicative of an assessed level of risk when the vehicle is being driven forwardly. The controller may though be configured to generate and cause display of both numerical and risk based graphical indicators at the same time. According to an aspect of the invention, there is provided a vehicle display system comprising a controller as described in the preceding paragraphs. The vehicle display system comprises a camera configured to capture image data, the display module having the display panel configured to show images formed from the image data captured by the camera and the sensor arrangement adapted to measure at least one parameter relating to an object of interest exterior to the vehicle.

The camera may be a rear-facing camera configured to be positioned at the rear of a vehicle.

The display module may comprise both a reflective mirror and the image display panel and the system may comprise means to allow a user to switch between a mirror mode and a display mode. The reflective mirror may comprise an electrochromic panel.

In some embodiments the display panel comprises an LCD or LED display panel, for example. The display module may be configured to be positioned within the interior of a vehicle. In some embodiments the display module may be configured to be mounted onto an interior surface of the windscreen of the vehicle. In this way, the display module may be used as a replacement for a traditional rear-view mirror of a vehicle in embodiments wherein the camera comprises a rear-facing camera. In further embodiments the display module may be configured to be mounted on an exterior surface of the vehicle. For example, the display module may be configured to be mounted so as to replace a wing-mirror of the vehicle. In yet further embodiments the system may comprise more than one display module.

The sensor arrangement may comprise at least one sensor operable in use to determine the distance between a vehicle in which the system is implemented and one or more objects of interest exterior to the vehicle. The, or each, distance sensor may be configured to be located at or on the rear of a vehicle and be operable to determine the distance between the rear of the vehicle and one or more objects behind the vehicle. The, or each, distance sensor may comprise an ultrasonic sensor, an infra-red sensor or a radar sensor, for example.

The sensor arrangement may comprise at least one motion sensor operable in use to determine the speed of one or more objects of interest within the environment of a vehicle in which the system is implemented. The, or each, motion sensor may be operable to determine the speed of the one or more objects of interest relative to the vehicle in which the system is implemented, which may comprise an approach speed or the speed at which the vehicle and the or each object are moving away from one another. The, or each, motion sensor may comprise an ultrasonic sensor, an infra-red sensor, or a radar sensor, for example.

The sensor arrangement may comprise one or more sensors for measuring a parameter relating to the state of a vehicle in which the system is implemented. The one or more sensors may comprise a motion sensor. In some embodiments, the system may comprise one or more motion sensors operable to determine the speed at which a vehicle in which the system is implemented is travelling. The, or each, motion sensor may be operable to measure the speed of rotation of one or more wheels of the vehicle. In some embodiments the, or each, motion sensor may comprise a speedometer within the vehicle. In other embodiments, the motion sensor may be a non-contact ground speed detector such as a Doppler Effect radar sensor. The system may comprise means to detect whether a reverse gear has been selected in a vehicle in which the system is implemented.

According to a further aspect of the invention, there is provided a vehicle comprising a controller and a vehicle display system in accordance with the preceding paragraphs. The vehicle may comprise a motor vehicle. The vehicle may comprise a road vehicle. The vehicle may be a car.

According to a further aspect of the invention, there is provided a method of forming an image using image data captured by a camera mounted within or on a vehicle comprising the steps of:

using the camera to capture image data;

obtaining information from one or more sensors within or on the vehicle which are operable to measure at least one parameter relating to the state of the vehicle in and/or one or more objects of interest exterior to the vehicle; and

generating an image from the captured image data and overlaying on the image a graphical indicator in dependence on the value of the at least one parameter measured by the one or more sensors.

The method of this aspect of the invention provides a way to overlay on a generated image a graphical indicator to assist a user in cognitively evaluating the image data when viewing the images. The method may comprise overlaying a graphical indicator on the generated image which illustrates information to a user relating to the distance between the vehicle and one or more objects of interest identified within the image data captured by the camera, and/or relating to the relative speed and/or trajectory of one or more objects of interest identified within the image data captured by the camera.

In some embodiments, the method comprises overlaying a graphical indicator on the generated image which comprises a numerical value in dependence on the values of the one or more parameters measured by the, or each, sensor. The numerical value may comprise the measured value obtained from the one or more sensors. In some embodiments, the method may comprise calculating the numerical value from the value(s) of the, or each, measured parameter. The numerical value may comprise the distance between the vehicle and an object of interest identified within the image data captured by the camera, for example.

The method may comprise overlaying on the image a graphical indicator which comprises a non-numerical indicator of the at least one parameter which may, for example, comprise a colour scale. Such a colour scale may be continuous or may be discrete. The method may comprise assessing a level of risk posed by an object of interest in accordance with predefined criteria and overlaying on the image a graphical indicator which is indicative of the assessed level of risk. Assessment of the level of risk may be based on the proximity of the object of interest to the vehicle and/or the relative speed of the object of interest to the vehicle and/or the trajectory of the object of interest relative to the vehicle. The method may comprise overlaying a graphical indicator that, for example, comprises a colour scale indicative of the assessed level of risk. In which case, the colour scale may be continuously varying or may vary in discrete steps. For example, in some embodiments the colour scale may comprise a first colour, which may be red, where the assessed level of risk is high. Likewise, the colour scale may comprise a second colour, which may be green, where the level of risk is assed to be low. The colour scale may have a range of different colours each being assigned a different meaning.

The method may comprise overlaying different types of graphical indicator depending on the mode of operation of the vehicle. For example, the method may comprise overlaying a graphical indicator which provides numerical data when the vehicle is being driven in reverse and a graphical indicator which is indicative of an assessed level of risk when the vehicle is being driven forwardly. The method may though comprise overlaying both numerical and risk based graphical indicators at the same time.

The method may comprise using one or more distance sensors to determine the distance between the vehicle and one or more objects of interest exterior to the vehicle. The method may comprise using one or more distance sensors located on the rear of the vehicle to determine the distance between the rear of the vehicle and one or more objects of interest behind the vehicle. The method may comprise using one or more distance sensors in the form of an ultrasonic sensor, an infra-red sensor or a radar sensor, for example.

In further embodiments, the method may comprise using one or more motion sensors to determine the speed of one or more objects of interest within the vehicle's environment. The one or more objects may comprise further vehicles. The method may comprise using one or more motion sensors to determine the speed of the one or more objects relative to the vehicle, which may comprise an approach speed or the speed at which the vehicle and the or each object are moving away from one another. The method may comprise using one or more motion sensors in the form of an ultrasonic sensor, an infra-red sensor or a radar sensor, for example. The method may comprise using at least one a motion sensor to determine the speed at which the vehicle is travelling. For example, the method may comprise using one or more motion sensors to measure the speed of rotation of one or more wheels of the vehicle. In some embodiments the, or each, motion sensor may comprise a speedometer within the vehicle. In other embodiments, the motion sensor may be a non-contact ground speed detector such as a Doppler Effect radar sensor. The method may comprise detect whether a reverse gear has been selected.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner. BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic plan view of an embodiment of a vehicle in accordance with an aspect of the invention incorporating an embodiment of a controller and a vehicle display system in accordance with further aspects of the invention;

Figure 2 is a schematic representation of an embodiment of a vehicle display system in accordance with an aspect of the invention as used in the vehicle of Figure 1 ;

Figure 3 is schematic representation of an embodiment of a display module forming part of a vehicle display system for a vehicle in accordance with an aspect of the invention, illustrating the application of a numerical graphical indicator to an image displayed;

Figure 4 is a schematic plan view of part of a dual carriageway illustrating the vehicle of Figure 1 in a typical driving situation; and

Figure 5 is schematic representation of an embodiment of a display forming part of a vehicle display system for a vehicle in accordance with an aspect of the invention, illustrating the application of risk based graphical indicators to an image displayed.

DETAILED DESCRIPTION

Referring to the Figures, a vehicle 10 incorporates an embodiment of a controller 1 1 and a vehicle display system 12 in accordance with aspects of the invention. The vehicle display system 12 is illustrated schematically in Figure 2 and comprises a camera 14, a processing unit 16 of the controller 1 1 , a display module 18, and a sensor arrangement 20, which includes one or more sensors 20a, 20b, 20c.

The processing unit 16 is in communication with the camera 14, the display module 18 and the sensor arrangement 20, for example by means of a vehicle network such as LIN (Local Interconnect Network). The camera 14 is mounted to the rear of vehicle 10 and is rearward facing in order to capture image data of the environment behind the vehicle. Captured image data is transmitted from the camera to the processing unit 16 where the image data is processed. The display module 18 includes at least one display panel 22, which may be an LCD or LED display panel on which the image data captured by the camera 14 can be displayed, subject to processing carried out in the processing unit 16. In use, the controller 1 1 receives image data from the camera 14 and outputs this image data to the display module 18. The controller 1 1 may receive image data from the camera 14 via the processing unit 16. The controller 1 1 further receives information from the one or more sensors 20a, 20b, 20c. As will be explained in more detail below, the processing unit 16 generates a graphical indicator 28 relating to an object of interest visible in the image displayed on the display module 18 in dependence on data from at least one of the sensors 20a, 20b, 20c. The processing unit is further operable to overlay the generated graphical indicator 28 over the displayed image to aid a user of the vehicle in assessing the environment around the vehicle.

In the present embodiment, the display module 18 is part of a rear-view mirror assembly 24 mounted on the windscreen 26 of the vehicle. The processing unit 16 in this embodiment is physically incorporated into the rear-view mirror assembly 24, though this is not essential and the processing unit 16 could be incorporated elsewhere in the vehicle. The rear-view mirror assembly 24 includes a reflective mirror (not shown) in addition to the display panel 22 and can be switched between a mirror mode in which the user, typically the driver of the vehicle, can see the environment behind the vehicle using the mirror in a conventional manner and a display mode in which the user views an image of the environment behind the vehicle captured by the rear facing camera on the display panel 22. The mirror may be in the form of an electrochromic device which can be switched between a reflective state and a transmission state, for example. In addition to switching between display and mirror modes, the user is able to make adjustments to the image displayed in the display mode, such as adjusting the brightness and contrast.

Displaying image data captured by the rear facing camera 14 provides the user with an increased field of view when compared with using the mirror mode and the image is not obstructed by the interior of vehicle or objects placed in the interior. However, for various reasons as discussed above, depth perception is different in the display mode and when a user switches from one mode to another they will have to make adjustments in their depth perception.

With reference to Figure 3, it will be appreciated that in order to assist a user in cognitively interpreting the image in the display mode, the processing unit 16 is configured to overlay on the image from the camera shown on the display module a graphical indicator 28 relating to an object of interest within the image. The object of interest is generally an object which is located externally to the vehicle but within its general environment. The graphical indicator 28 provides data relating to the state of the object of interest. For example, the graphical indicator may provide data to assist the user with depth perception. Data used to generate the graphical indicator is derived from the sensor arrangement 20, which is used to measure at least one parameter relating to the object of interest and/or its relationship with the subject vehicle 10. In one embodiment, the graphical indicator 28 provides data regarding the distance from the subject vehicle 10 to the object of interest 30, which data is displayed in a suitable format for the user to interpret. The graphical indicator 28 may be numeric, for example indicating the distance accurately in meters as illustrated in Figure 3. Alternatively, the graphical indicator 28 could be a non-numeric display such as a colour distance bar in which distance is accurately represented by a colour scale or a distance grid for example.

Displaying data relating to the distance of an object of interest in the displayed image means that the user does not have to rely exclusively on a visual judgment of the distance. Instead, the user is provided with distance to object information, which over time will aid them in developing their depth perception in the display mode by making a connection between the actual distance to an object of interest and the distance as shown on the display. Information regarding the actual distance to an object of interest is derived from the sensor system 20, which incorporates distance sensors 20a capable of measuring or otherwise detecting distances to objects exterior to but within the general environment of the vehicle. The distance sensors 20a may be ultrasonic, infra-red or radar sensors, for example. Data from the sensors 20a is provided to the processing unit 16 which generates the appropriate graphical overlay.

The type of information which will be of most assistance to a user and the way it is best presented may differ under different operating modes of the vehicle. For example, when a vehicle is being driven in reverse at relatively slow speeds and where the user is looking almost exclusively at the display whilst guiding the vehicle, displaying accurate distance information in a numerical form or in the form of a distance bar or grid may be the most appropriate way to assist the user with depth perception. Under these circumstances, the user has time to assimilate detailed information regarding distance and can constantly monitor changes in the distance information whilst controlling the vehicle. However, if a vehicle is being driven forwardly at higher speeds, it may be more difficult for a driver to assimilate detailed information on distance provided in this way when glancing at the rear- view display. Also, different types of objects will generally be of interest to a user depending on the driving mode. When reversing, any object within the path of the subject vehicle 10 may be of interest, whether stationary or moving. However, when driving forwardly at higher speeds, objects of interest that are most likely to be of concern will tend to be other vehicles, which may be approaching the user's vehicle. Figure 4 illustrates a typical forward driving scenario in which a driver is using the vehicle display system 12, as hereinbefore described, in a display mode to assess traffic behind them with a view to carrying out an overtaking manoeuvre. As illustrated, the subject vehicle 10 is being driven in the inside lane of a dual carriageway 32. A second vehicle 34 is following the subject vehicle 10 in the same lane, a third vehicle 36 is approaching the subject vehicle 10 from behind in the outer lane, and a fourth vehicle 38 is in front of the subject vehicle 10 in the inner lane. Before carrying out a manoeuvre to overtake the vehicle 38 in front, the driver of the subject vehicle 10 uses the display to assess the proximity and relative speeds of the vehicles 34, 36 behind them, particularly that of the third vehicle 36 approaching in the outside lane. In these circumstances, a numeric display of the distances to the second and third vehicles 34, 36, or even the use of colour coded distance bars, may not be the most appropriate. In an alternative embodiment, the vehicle display system 12 overlays a graphical indicator 28 which provides the user with easily identifiable guidance as to a level of risk associated with an object of interest. The level of risk is assessed by the processing unit 16 using data from the sensor system 20 and/or from the camera according to an appropriate algorithm and the processing unit overlays an appropriate graphical indicator 28 indicative of the assessed level of risk in relation to the object in the displayed image. Typically, the level of risk will be assessed, at least in part, based on the proximity of an object of interest to the subject vehicle 10. For example, an object of interest that is detected as being at or within a first predetermined distance of the subject vehicle 10 can be assigned a high risk, one that is further away than the first predetermined distance up to a second predetermined distance larger than the first can be assigned a medium risk, and one that is at or beyond the second predetermined distance a low risk. Different graphical indicators can be assigned to each level of risk and overlaid on the displayed image in association with a respective object of interest in the displayed image. In one embodiment, a colour coding system is used to denote the various levels of risk such as red for high risk, amber for medium risk, and green for low risk. However, other colours could be used and the user may be provided an option to vary the colours to compensate for colour blindness or for user preference. In some cases a two colour system to indicate risk may be appropriate such a red for high risk and green for low risk as this provides a simpler system for a user to interpret and may provide less cluttered displays. Other types of graphical indicator 28 could also be used to indicate the various levels of risk, such as flashing or non-flashing icons. Where a colour coding system is used, the whole or part of the object of interest in the displayed image may be overlaid with a coloured graphical indicator 28 or a graphical indicator which forms a coloured halo may be provided about at least part of the object of interest. Alternatively, the graphical indicator 28 can take the form of a coloured icon visually associated with the respective object of interest.

This use of a graphical indicator 28 which informs the user of a level of risk associated with an object of interest in the display will allow the user to assess quickly when it is safe to carry out a manoeuvre, such as overtaking, without having to rely exclusively on their perception of depth or evaluating numerical data and so is intuitive.

In a further embodiment, the vehicle display system 12 can also take into account parameters other than distance when determining a level of risk for an object of interest. The criteria for assigning the various level of risk may also be dependent on the position of the object of interest relative to the subject vehicle 10. For example, on a multi-lane carriageway such as that illustrated in Figure 4, a vehicle in a different, overtaking, lane such as vehicle 36 may be assigned a high risk at a greater distance from the subject vehicle 10 than one travelling in the same lane.

Figure 5 illustrates schematically a display unit 18 displaying an image from the camera 14 on the subject vehicle 10 of Figure 4 with risk based graphical indicators 28a and 28b overlaid in respect of the images of vehicles 34 and 36. The graphical indicator 28a applied to the image vehicle 36 indicates a high risk whilst the graphical indicator 28b applied to the image of vehicle 34 indicates a medium risk. In this scenario, the third vehicle 36 has been assigned a higher risk than the second vehicle 34 as it is approaching in the outside, overtaking lane. Parameters used to asses a level of risk may also include the speed, or relative speed, of the object of interest and/or its trajectory. For example, where a vehicle is approaching from the rear quickly, it may be assigned a high risk at a greater distance from the subject vehicle 10 than would be the case if approaching more slowly. Also, if a vehicle is detected as changing lanes, especially if moving from the same lane as the subject vehicle 10 into an overtaking lane, it may be assigned a high risk at a greater distance from the subject vehicle 10 than one which remains in the same lane. In the example illustrated in Figure 4, if the processing unit 16 determines that the second vehicle 32 has started to move into the outside lane it may assign it a higher level of risk and overlay an appropriate graphical indicator to warn the driver.

The sensor system 20 includes appropriate sensors for detecting and measuring the various parameters that are to be used in applying appropriate graphical indicators 28. In addition to the distance sensors 20a, further sensors of detecting parameters of objects within the environment of the subject vehicle may be used. For example, sensors for detecting the speed and/or trajectory of objects of interest can be provided. Such sensors are well known in the art. Alternatively, the speed and/or trajectory of an object relative to the subject vehicle can be calculated using data from the distance sensors 20a.

The sensor system 20 may also include one or more sensors for determining the state of the subject vehicle 10. Such sensors may be operable to detect one or more parameters relating to the subject vehicle's trajectory and/or speed for example. In the illustrated embodiment, the sensor system 20 comprises a sensor 20b operable to determine the speed at which the subject vehicle travelling. This might include a ground speed laser sensor or may be provided as part of the vehicle's speedometer system. The sensor system 20 also comprises a position sensor 20c operable to determine the angular position of the steering wheel 40 of the vehicle 10. Data from the speed sensor 20b and position sensor 20c can be used in combination to calculate the trajectory of the vehicle 10 in motion. The sensor arrangement 20 may include a means for determining whether the subject vehicle 10 is in a reverse gear. This might comprise detecting when a reverse gear is selected.

It should be appreciated that other sensor arrangements can be used, either in addition to those described above or as an alternative, in order to provide the processing unit 16 with the data required to generate an appropriate graphical indicator 28.

As noted above, different types of graphical indicator 28 may be appropriate for different modes of vehicle use. Embodiments of a controller 1 1 and vehicle display system 12 in accordance with an aspect of the invention can be configured to apply the same types of graphical indicator 28 at all times when it is in use or configured so that different types of graphical indicator 28 are used depending on the mode of use of the vehicle at the time. In one embodiment, the controller 1 1 and system 12 are configured to switch automatically between different types of graphical indicator depending on the mode of use of the vehicle. For example, the system may apply graphical indicators which provide detailed distance information when a reverse gear is selected and switch to a risk based display when the vehicle is being driven forwardly. However, in some situations a combination of different types of graphical indicator 28 may be appropriate. For example, when the subject vehicle 10 is being driven in reverse, the system 12 may display both numerical data relating to objects of interest in the display and also apply risk based graphical indicators 28 in relation to certain objects of interest that are assessed to be in the vehicle's path and/or determined to be in close proximity to the subject vehicle, for example. The system 12 may allow the user to select from different types of graphical indicator 28 to be displayed. The controller 1 1 and system 12 may be configured so that graphical indicators 28 are only applied to the displayed image in certain modes of operation of the vehicle. For example, the controller 1 1 and system 12 can be configured to overlay graphical indicators 28 when the subject vehicle 10 when reverse gear is selected but not at other times, such as when the vehicle is being driven forwardly, particularly at speed.

In alternative embodiments, the display system 12 can comprise more than one camera 14 to provide image data and/or may use apparatus other than a camera to obtain image data. References herein to a camera should be understood as encompassing other image capturing systems.

The display module 18 need not be provided as part of a rear-view mirror 24 mounted to a windscreen but be located anywhere where it can be viewed. This may be within the cabin of a vehicle or externally, say within a side or wing mirror assembly.

The vehicle display system 12 in accordance with an aspect of the invention is not limited to use with rear facing cameras but can be applied to image data captured from cameras which face in other directions relative to the subject vehicle, including sideways and forward facing cameras.

The above embodiments are described by way of example only. Many variations are possible without departing from the scope of the invention as defined in the appended claims.

Claims

A controller for a vehicle display system, the controller comprising:

a first input configured to receive image data from a camera;

a processing unit operable in dependence on data from the at least one sensor to overlay on the image shown on the display module at least one graphical indicator, the processing unit being configured to generate the at least one graphical indicator in dependence on the value of the at least one parameter measured by the sensor arrangement in relation to an object of interest in the displayed image.

A controller as claimed in claim 1 , wherein the controller is configured to generate the at least one graphical indicator on the display module in dependence on the distance between a vehicle in which the controller is implemented and the object of interest.

A controller as claimed in claim 2, wherein the controller is configured to generate the at least one graphical indicator on the display module to provide a numerical indication of the distance between the vehicle in which the controller is implemented and the object of interest.

A controller as claimed in claim 2, wherein the controller is configured to generate the at least one graphical indicator on the display module to provide a graphical representation of the distance between the vehicle in which the controller is implemented and the object of interest.

A controller as claimed in any one of claims 1 to 4, wherein the controller is configured to generate the at least one graphical indicator on the display module in dependence on the speed and/or trajectory of the object of interest relative to a vehicle in which the controller is implemented.

6. A controller as claimed in any one of claims 1 to 5, wherein the controller is configured to assess a level of risk posed by an object of interest and to generate the at least one graphical indicator on the display module to indicate the assessed level of risk.

7. A controller as claimed in any one of the preceding claims, wherein the controller is configured to cause the display of different types of graphical indicator on the display module in dependence on the operating mode of the vehicle in which the controller is implemented.

8. A controller as claimed in claim 7, wherein the operating mode of the vehicle comprises the vehicle operating in a forward gear or a reverse gear.

9. A vehicle display system comprising a controller as claimed in any one of the preceding claims, the vehicle display system further comprising a camera configured to capture image data, the display module having the display panel configured to show images formed from the image data captured by the camera and the sensor arrangement adapted to measure at least one parameter relating to an object of interest exterior to the vehicle.

10. A vehicle display system as claimed in claim 9, wherein the camera comprises a rear-facing camera, optionally configured to be positioned towards the rear of a vehicle.

1 1 . A vehicle display system as claimed in claim 9 or claim 10, wherein the display module comprises both a reflective mirror and the image display panel, the system comprising means to allow a user to switch between a mirror mode and a display mode.

12. A vehicle display system as claimed in claim 1 1 , wherein the reflective mirror comprises an electrochromic panel.

13. A vehicle display system as claimed in any one of claims 9 to 12, wherein the sensor arrangement comprises at least one sensor operable in use to determine the distance between a vehicle in which the system is implemented and one or more objects of interest exterior to the vehicle.

14. A vehicle display system as claimed in any one of claims 9 to 13, wherein the sensor arrangement comprises at least one sensor operable in use to determine the speed of one or more objects of interest exterior to the vehicle in which the system is implemented.

15. A vehicle display system as claimed in any one of claims 9 to 14, wherein the sensor arrangement comprises one or more sensors for measuring a parameter relating to the state of a vehicle in which the system is implemented.

16. A vehicle comprising a controller according to any one of claims 1 to 8 and a vehicle display system according to any one of claims 9 to 15.

17. A method of forming an image from a camera mounted within or on a vehicle comprising the steps of:

using the camera to capture image data;

obtaining information from one or more sensors within or on the vehicle which are operable to measure at least one parameter relating to the state of the vehicle and/or one or more objects of interest exterior to the vehicle; and

generating an image from the captured image data and overlaying on the generated image at least one graphical indicator in dependence on the values of the at least one parameter measured by the one or more sensors.

18. A method as claimed in claim 17, the method comprising overlaying the at least one graphical indicator on the generated image so as to illustrate information to a user relating to a distance between the vehicle and an object of interest identified within the image data captured by the camera.

19. A method as claimed in claim 18, wherein the method comprises overlaying the at least one graphical indicator on the generated image so as to provide a numerical indication of the distance between the vehicle and an object of interest identified within the image data captured by the camera.

20. A method as claimed in claim 18, the method comprising overlaying on the generated image the at least one graphical indicator so as to provide a non- numerical indication of the distance between the vehicle and an object of interest identified within the image data captured by the camera.

21 . A method as claimed in any one of claims 17 to 20, wherein the method comprises assessing a level of risk posed by an object of interest identified within the image data captured by the camera in accordance with predefined criteria and overlaying on the generated image the at least one graphical indicator so as to indicate the assessed level of risk.

22. A method as claimed in any one of claims 17 to 21 , wherein the method comprises overlaying different types of graphical indicator in dependence on the mode of operation of the vehicle at the time the generated image is displayed.

23. A method as claimed in any one of claims 18 to 20 or claims 21 or 22 when

depending through claim 18, wherein the method comprises using one or more distance sensors to determine the distance between the vehicle and one or more objects of interest exterior to the vehicle.