Patent Description:
The invention can be applied in light, medium and heavy-duty vehicles, such as trucks, buses and construction equipment.

A trend in industrial vehicles is to replace conventional mirrors by a camera assembly which comprises a camera arranged on an exterior part of a vehicle, for providing a captured image of a surrounding area of the vehicle, for example an area located rearwards and along a vehicle side. An image, resulting from the processing of the captured image, can be displayed on a monitor inside the driver's compartment.

It is of paramount importance that the image displayed provides the necessary visual information for the driver to ensure the safety of people and the integrity of objects and goods. For this reason, an overlaid element on the captured image could be necessary to help the driver.

Indeed, it could be difficult for the driver to evaluate distances when changing from mirrors to camera assemblies, the size of the rear part of the vehicle being harder to evaluate depending on the trailer angle.

Patent literature <CIT> discloses a viewing system, for a vehicle, displaying, in the vehicle interior, images of the vehicle environment together with information on a future vehicle route, e.g. a trailer of a commercial vehicle, so that they are visible for a driver while driving.

Patent literature <CIT> discloses a method for determining hitch angle in a vertical or horizontal plane between a vehicle and a trailer attached to the vehicle by means of a tow hitch. The method includes the steps of tracking a marker associated with the trailer across a field of view of a rearward-looking video camera and converting a lateral displacement of the marker in the field of view to an angular displacement.

Patent literature <CIT> discloses a method and system for measuring an articulation angle between a vehicle and trailer using a vehicle-mounted camera.

The present invention aims to solve all or some of the disadvantages mentioned above.

For this purpose, the present invention relates to a method for adapting an overlaid image displayed on a monitor located in a cab of a vehicle, according to claim <NUM>.

The at least one recognizable pattern includes a background element from the captured image. The background element includes a line or an area delimiting the ground and the sky. In this case, the background is used to define the horizontal dimension.

According to another aspect of the invention, the at least one recognizable pattern includes an element of the vehicle shown in the captured image. Preferably, said element is comprised in the vehicle side as the vertical limit of the trailer. In this case, the horizontal dimension could be in a different frame of reference than the background. The horizontal dimension is possibly a straight or curved line.

The monitor is considered as a display means with a rectangular shape.

The overlaid element is delimited on the overlaid image by a vertical line intersecting the pointer, the vertical line being transverse to the horizontal dimension.

The camera-monitor assembly is intended to replace a side mirror of the vehicle.

According to one aspect of the invention, the location corresponds to a geometrical point of the vehicle side, preferably visually defining the size of the vehicle side. In particular, the location of the embedded element can be a top rear corner of the vehicle side, low rear corner or another element part of a contour of the vehicle side shown on the captured image.

The method for adapting an overlaid image enables a driver of the vehicle to better evaluate distances when changing from mirrors to CMS. Indeed, although the vehicle side is visible in the monitor, it takes more or less space in the captured image depending on the vehicle side position.

In this context, the adapting overlayer gives a visual indication to the driver. The overlaid element is smaller at a low cab/vehicle side angle than at a high angle but the distance represented by the overlaid element is the same.

Another advantage of the method is that the adapting overlayer follows the vehicle side when turning. In addition, the field of vision is never obstructed by the adapting overlayer.

According to an aspect of the invention, the step of defining the target on the captured image is preceded by a step of selecting the location on the embedded element of the vehicle.

This allows the driver to define himself the most convenient location for the position of the pointer. The driver can therefore personalize the adapting overlayer according to his or her preferences.

According to an aspect of the invention, the step of selecting the location on the embedded element of the vehicle corresponds to a manual input.

According to one aspect of the invention, the manual input corresponds to a manual interaction with the monitor, the monitor being a touch screen. This allows a fast selection to define de location.

According to an aspect of the invention, the overlaid element corresponds to a part of a trajectory line of the location on the embedded element of the vehicle side.

This visual indication not only helps the driver to evaluate distances in the monitor but also gives a hint on the forecasted trajectory of the vehicle.

According to an aspect of the invention, a memory of the control unit comprises a plurality of trajectory lines, each corresponding to a position of the vehicle side with respect to the cab, the step of displaying the overlaid image including a selection of a proper trajectory line among the plurality of trajectory lines, the proper trajectory line intersecting the pointer.

This arrangement allows limiting the processing resources of the control unit as a move of the pointer is followed by a new selection of a proper trajectory line. The proper trajectory line should not be continuously calculated.

Preferably, the selection is done continuously to follow the displacement of the pointer. In particular, continuously means that the selection is done according to a defined frequency that could be variable depending on a tuned refreshing rate.

According to an aspect of the invention, the method for adapting the overlaid image comprises a step of calibration preceding the step of displaying the overlaid image and consisting in defining a correspondence between several positions of the target on the captured image and several relative positions of the cab and the vehicle side.

Preferably, the correspondence is used for defining the adapting overlayer according to the pointer position.

According to an aspect of the invention, said correspondence is saved in the memory together with an identification reference of a trailer on which the vehicle side is located.

This arrangement enables to have one calibration for a particular trailer that is used with the cab. By cab of the vehicle, it has to be understood tractor of the vehicle that is configured to cooperate with the trailer.

According to an aspect of the invention, the processing of the step of tracking the target position and of the step of displaying the overlaid image are interrupted by and resumed after at least one step of temporary uncoupling the trailer from the cab.

The fact that the correspondence is memorized together with the identifying reference of the trailer allows one or several temporarily uncoupling of the trailer without necessitating going through the steps of defining the target and calibrating the trajectory lines. According to an aspect of the invention, the defined target is memorized by the control unit.

According to an aspect of the invention, the method can be implemented several times with the same trailer. Preferably, an input step can be manually initiated to proceed to a reset and repeat the method. This enables for example to define a different target on the captured image.

According to one aspect of the invention, the relative positions of the cab and the vehicle side correspond to cab/vehicle side angles.

According to an aspect of the invention, the step of calibration is realized while driving by determining the correspondence during at least one turn of the vehicle.

This allows a simple calibration once the target is defined. One can to drive normally to define the correspondence. According to one aspect of the invention, the at least one turn comprises two turns. Preferably, the two turns are two turns in opposed directions.

According to an aspect of the invention, during the step of displaying the overlaid image, the or each trajectory line is cut at the pointer level and a fraction of said trajectory line is erased, said fraction starting from the pointer to the other side of the monitor that is extending transversally to the horizontal dimension and that is opposed to the cab position in the captured image.

According to an aspect of the invention, the method for adapting the overlaid image is carried out for several distinct targets on the captured image to display several corresponding adapting overlayers in the overlaid image.

The adapting overlayers move continuously as each pointer is following its corresponding target. The overlaid elements are also permanently adapted with respect to the position of the pointers.

The overlaid image is then dynamic to help the driver assess distances without disturbing his vision, as the region of the image outside the vehicle side size is not covered.

The present invention also concerns a computer program comprising program code means according to claim <NUM>.

The present invention further concerns a control unit according to claim <NUM>.

The invention also concern a vehicle comprising a control unit as disclosed above.

The different aspects defined above that are not incompatible can be combined.

The invention will be better understood with the aid of the detailed description that is set out below with reference to the appended drawing in which:.

As illustrated in <FIG>, a vehicle <NUM> and more specifically an industrial vehicle is disclosed. Although the invention will be described with respect to a truck, the invention is not restricted to this particular vehicle <NUM>, but may also be used in other vehicles, such as a bus.

The vehicle <NUM> comprises a cab <NUM> or tractor. The cab <NUM> defines a driver compartment. The vehicle <NUM> can also be configured to include a trailer <NUM> connected both mechanically and electrically to the cab <NUM>, as shown in <FIG>.

The trailer <NUM> is supported by wheels and comprises a side wall <NUM> also referred to as vehicle side <NUM>. The vehicle side <NUM> has a lower rear corner <NUM> and a top rear corner <NUM>.

Furthermore, a camera-monitor assembly <NUM> comprises a camera <NUM> for providing a captured image <NUM> as shown in <FIG> of an area located rearwards and along the vehicle side <NUM>, the camera <NUM> thus replacing a conventional side exterior mirror of the vehicle <NUM>.

Here only one camera-monitor assembly <NUM> is described. However, the vehicle <NUM> can be equipped with two of such camera-monitor assemblies <NUM>, the second being located on the other side of the cab <NUM>.

The camera-monitor assembly <NUM> further includes a monitor <NUM> inside the driver's compartment for displaying an image resulting from the processing of the image provided by the camera <NUM>. The camera-monitor assembly <NUM> further comprises a control unit <NUM>.

The control unit <NUM> is configured to receive data from various sensors or components of the vehicle <NUM>, to process this data, to control the operation of various components of the vehicle <NUM>, possibly depending on the information received. The control unit <NUM> is exemplified as an electronic control unit that may be adapted to control working vehicle operations and/or to process data relevant for the operation of the vehicle <NUM>. As non-limiting and non-exhaustive examples, the feature "processing data" may include one or more of determining, storing, transmitting or receiving data.

As shown in <FIG>, there is provided a method for adapting an overlaid image <NUM> displayed on the monitor.

The method comprises a step E1 consisting in defining at least one location <NUM> on an embedded element of the vehicle side <NUM> as target <NUM> on the captured image <NUM>. Here several locations <NUM> and corresponding targets <NUM> are defined.

The step E1 of defining the target <NUM> on the captured image <NUM> is preceded by a step Es of selecting the locations <NUM> on embedded elements of the vehicle side <NUM>.

The locations <NUM> correspond to geometrical points of the vehicle side <NUM>, preferably visually defining the size of the vehicle side <NUM>. In <FIG>, four locations have been defined and exemplified including the top rear corner <NUM>, the lower rear corner <NUM> or other elements part of a contour of the vehicle side <NUM>.

The step Es of selecting the locations on the embedded elements of the vehicle corresponds to a manual input. The manual input corresponds to a manual interaction with the monitor <NUM>, the monitor <NUM> being for example a touch screen. The defined targets <NUM> are stored by the control unit <NUM>.

Then, the method comprises a step E2 consisting in processing the captured image <NUM> by tracking the positions of the targets <NUM> and by tracking at least one recognizable pattern <NUM> linked to a horizontal dimension <NUM> on the captured image <NUM>.

As illustrated in <FIG>, the at least one recognizable pattern <NUM> includes a background element from the captured image <NUM> and more particularly a line or an area delimiting the ground and the sky. The horizontal dimension <NUM> is possibly a straight or curved line depending on the captured image <NUM>.

Alternatively, the at least one recognizable pattern <NUM> can include an element of the vehicle <NUM> shown in the captured image <NUM>.

The method comprises a step E3 consisting in displaying on the monitor <NUM> the overlaid image <NUM> including the captured image <NUM> and adapting overlayers <NUM>, each adapting overlayer <NUM> corresponding to a target <NUM>.

Each adapting overlayer <NUM> comprises a pointer <NUM> on the target <NUM> and an overlaid element <NUM>, the overlaid element <NUM> extending in an area of the captured image delimited on one side by the pointer <NUM> and on the other side by a side <NUM> extending transversally to the horizontal dimension and of the monitor <NUM> corresponding to the cab <NUM> position in the captured image <NUM>.

This delimitation is considered horizontally according to the horizontal dimension <NUM> defined with the orientation of the at least one recognizable pattern <NUM>.

The monitor <NUM> can be a display means having a rectangular form.

The overlaid element <NUM> is delimited on the overlaid image <NUM> by a vertical line <NUM> intersecting the pointer <NUM>, the vertical line <NUM> being transverse to the horizontal dimension <NUM>. The overlaid element <NUM> corresponds to a part of a trajectory line of the location on the embedded element of the vehicle side <NUM>.

A memory <NUM> of the control unit <NUM> comprises a plurality of trajectory lines, each corresponding to a position of the vehicle side <NUM> with respect to the cab <NUM>.

The step E3 of displaying the overlaid image <NUM> includes a selection of a proper trajectory line among the plurality of trajectory lines, the proper trajectory line intersecting the pointer <NUM>.

The selection is done continuously to follow the displacement of the pointer <NUM>. In particular, continuously means that the selection is done according to a defined frequency that could be variable depending on a tuned refreshing rate.

During the step E3 of displaying the overlaid image <NUM>, the or each trajectory line is cut at the pointer <NUM> level and a fraction of said trajectory line is erased, said fraction starting from the pointer <NUM> to the other side <NUM> of the monitor that is extending transversally to the horizontal dimension <NUM> and that is opposed to the cab <NUM> position in the captured image <NUM>.

The method also comprises a step Ec of calibration preceding the step E3 of displaying the overlaid image <NUM> and consisting in defining a correspondence between several positions of the target <NUM> on the captured image <NUM> and several relative positions of the cab <NUM> and the vehicle side <NUM>.

The relative positions of the cab <NUM> and the vehicle side <NUM> correspond to cab/vehicle side angles. The correspondence is used for defining the adapting overlayer <NUM> according to the pointer <NUM> position.

Said correspondence is saved in the memory <NUM> of the control unit <NUM> together with an identification reference of a trailer <NUM> on which is located the vehicle side <NUM>.

The step Ec of calibration is realized while driving by determining the correspondence during at least one turn of the vehicle. The at least one turn comprises two turns. Preferably, the two turns are two turns in opposed directions.

The processing of the step E2 of tracking the target position and the step E3 of displaying the overlaid image <NUM> can be interrupted by and resumed after at least one step Eu of temporary uncoupling the trailer <NUM> from the cab <NUM>.

The method can also be implemented several times with the same trailer <NUM> to modify the targets <NUM>. An input step can be manually initiated to proceed to a reset and repeat the method.

A computer program comprising program code means for performing the steps of the method for adapting an overlaid image <NUM> displayed on the monitor <NUM> located in the cab <NUM> of the vehicle <NUM> is run on the control unit <NUM>.

The method for adapting an overlaid image enables a driver of the vehicle to better evaluate distances when changing from mirrors to CMS. Indeed, although the vehicle side <NUM> is visible in the monitor <NUM>, it takes more or less space in the captured image depending on the vehicle side <NUM> position.

Claim 1:
A computer-implemented method for adapting an overlaid image (<NUM>) displayed on a monitor (<NUM>) located in a cab (<NUM>) of a vehicle (<NUM>) comprising a tractor and a trailer, the cab of the vehicle being the tractor, the tractor being configured to cooperate with the trailer, the vehicle (<NUM>) comprising at least one camera-monitor assembly (<NUM>) provided with a control unit (<NUM>) and a camera (<NUM>) for providing a captured image (<NUM>) of an area located rearwards and along one and/or the other vehicle side (<NUM>), the method comprising:
- (E1) defining a location (<NUM>) on an embedded element of the vehicle side (<NUM>) as a target (<NUM>) on the captured image (<NUM>),
- (E2) processing the captured image (<NUM>) by tracking the target (<NUM>) position and by tracking at least one recognizable pattern (<NUM>) linked to a horizontal dimension (<NUM>) on the captured image (<NUM>), the recognizable pattern including a background element from the captured image, the background element including a line or an area delimiting the ground and the sky,
- (E3) displaying on the monitor (<NUM>) an overlaid image (<NUM>) including the captured image (<NUM>) and an adapting overlayer (<NUM>), the adapting overlayer (<NUM>) comprising a pointer (<NUM>) on the target (<NUM>) and an overlaid element (<NUM>), the overlaid element (<NUM>) extending in an area of the captured image (<NUM>) delimited, horizontally according to the horizontal dimension (<NUM>) defined with the orientation of the at least one recognizable pattern (<NUM>) , on one side by the pointer (<NUM>) and on the other side by a side (<NUM>) of the monitor (<NUM>) extending transversally to the horizontal dimension and corresponding to the cab (<NUM>) position in the captured image (<NUM>).