DE102017214513A1 - Method for operating an assistance system for a vehicle and assistance system - Google Patents

Abstract

A method for operating an assistance system (10) for a vehicle is specified. The assistance system comprises a sensor device for determining a direction characteristic which is representative of a viewing direction (2) of a driver of the vehicle, and for determining a position characteristic which is representative of a head position (3) of the driver. In the method, a reference characteristic value representative of coordinates of a predetermined point (4a, 4b) with respect to the vehicle in three-dimensional space is provided; at least one initial direction and position characteristic value is determined; depending on the at least one initial position characteristic value and the reference characteristic value, a respective calibration characteristic value is determined, which is representative of a vector which connects the head position (3) to the point (4a, 4b); depending on the at least one initial directional characteristic value and the respective calibration characteristic value, a transformation characteristic value is determined which is representative of a geometric transformation between the at least one initial directional parameter and the respective calibration parameter; and corrected depending on the transformation characteristic value subsequently determined direction and position characteristics. Furthermore, a corresponding assistance system (10) is specified.

Description

The invention relates to a method for operating an assistance system for a vehicle and to a corresponding assistance system, computer program and computer program product.

For example, today's eye tracking devices ("eye tracking") are a camera sensor that outputs a three-dimensional viewing direction of a user. In addition, for example, a head position of the user can be output.

Even with high precision of the camera sensor, a vector describing the viewing direction can not be accurately determined due to the individual eye anatomy (e.g., position of the fovea). The eye geometry can not be detected by the camera sensor. If the eye geometry is not taken into account, then the line of sight measurement is inaccurate.

The object on which the invention is based is to provide a method for operating an assistance system for a vehicle as well as a corresponding assistance system, which allows user-spanning precise viewing direction detection.

The object is solved by the independent claims. Advantageous embodiments are characterized in the subclaims.

According to a first aspect, the invention relates to a method for operating an assistance system for a vehicle. The assistance system comprises a sensor device for determining a direction characteristic which is representative of a line of sight of a driver of the vehicle, as well as for determining a position characteristic which is representative of a head position of the driver.

The method provides a reference characteristic that is representative of coordinates of a predetermined point of the vehicle in three-dimensional space; then at least one initial direction and position characteristic value is determined; depending on the at least one initial position characteristic value and the reference characteristic value, a respective calibration characteristic is determined, which is representative of a vector which connects the head position to the point; Depending on the at least one initial directional characteristic value and the respective calibration characteristic value, a transformation characteristic value is determined which is representative of a geometric transformation between the at least one initial directional characteristic value and the respective calibration characteristic value; Finally, depending on the transformation characteristic value, subsequently determined directional and position characteristic values are corrected.

Advantageously, this allows a more accurate viewing direction measurement than is possible without calibration or adaptation to the individual eye anatomy of the corresponding driver. Thus, e.g. statements are made with greater accuracy as to which objects were focused by the driver. In particular, such a precise view control in the vehicle can be guaranteed.

The sensor device may in particular be a camera. The predetermined point is preferably arranged in a field of vision of the driver in normal operation of the vehicle, ie in a front region of the vehicle or in front of the vehicle.

In an advantageous embodiment according to the first aspect of the driver is asked before determining the at least one initial direction and position characteristic value of the vehicle to focus the predetermined arranged point.

In an advantageous embodiment according to the first aspect, the steps for determining the transformation characteristic value are performed exactly once.

In an alternative, advantageous embodiment according to the first aspect, the steps for determining the transformation characteristic value are performed several times. In particular, the directional and position characteristic value as well as the calibration characteristic value are determined repeatedly in this connection. By way of example, this can be done repeatedly depending on the same point arranged with respect to the vehicle; Alternatively, points located at different or at different coordinates can be traced back. The transformation characteristic value for the correction of subsequent directional and positional characteristic values is then determined as a function of the individual directional characteristic values and associated calibration characteristic values. This advantageously increases the accuracy of the geometric transformation.

In a further advantageous embodiment according to the first aspect, the assistance system comprises a projection device, which is set up to irradiate the point arranged with respect to the vehicle. Alternatively or additionally, the assistance system comprises a movement mechanism and a marker, wherein the movement mechanism is set up to move the marker from a neutral position to the point arranged in relation to the vehicle and back. The method is prior to determining of the at least one initial direction and position characteristic value, the projection device or the movement mechanism is controlled in such a way that the predetermined point is illuminated or the marker is moved to the predetermined point.

According to a second aspect, the invention relates to an assistance system for a vehicle. The assistance system comprises a sensor device for determining a direction characteristic which is representative of a line of sight of a driver of the vehicle, as well as for determining a position characteristic which is representative of a head position of the driver. Furthermore, the assistance system comprises a control unit which is set up to carry out the method according to the first aspect.

In an advantageous embodiment according to the second aspect, the assistance system comprises a projection device that is set up to irradiate a point arranged in a predetermined manner relative to the vehicle in three-dimensional space.

Advantageously, this enables a simple and precise identification of the predetermined point to be focused by the driver. In this connection, the knowledge is used that an accuracy of the calibration characteristic increases with the distance of the point to be focused. By projection, a high distance of the predetermined arranged point can be selected and thus contribute to an extremely precise calibration of the gaze detection device.

The projection device may be, for example, a laser. The projection device can in particular be designed to illuminate a flat surface in front of the vehicle, for example the roadway.

In a further advantageous embodiment according to the second aspect, the assistance system comprises a movement mechanism and a marker, wherein the movement mechanism is arranged to move the marker from a neutral position to the point arranged with respect to the vehicle and back to the neutral position.

Advantageously, this enables a simple and precise identification of the point to be focused by the driver. The marker can be arranged, for example, inside, but especially outside of the vehicle. Advantageously, the marker is arranged in the front region of the vehicle, for example on the hood. In particular, the marker is an optically salient sign. By way of example, a company logo of the vehicle manufacturer can be considered for this purpose, which is often arranged in the front region of the engine hood. In this connection, the knowledge is used that an accuracy of the calibration characteristic increases with the distance of the point to be focused. By using the movable marker in the front area of the vehicle, a higher distance of the given point than by mere display on a screen in the vehicle can be selected and thus contribute to an extremely precise calibration of the gaze detection device.

The movement mechanism may, for example, be a folding mechanism which pivots the marker into the driver's field of vision.

According to a third aspect, the invention relates to a computer program for operating an assistance system. The computer program is designed to carry out a method according to the first aspect when executed on a data processing device.

According to a fourth aspect, the invention relates to a computer program product comprising executable program code. The program code executes the method according to the first aspect when executed by a data processing device.

Embodiments of the invention are explained in more detail below with reference to the schematic drawings.

• 1 ein Fahrzeug mit dem erfindungsgemäßen Assistenzsystem; und
• 2 ein beispielhaftes Ablaufdiagramm eines Verfahrens zum Betreiben des Assistenzsystems gemäß 1.

Show it:

• 1 a vehicle with the assistance system according to the invention; and
• 2 an exemplary flowchart of a method for operating the assistance system according to 1 ,

1 shows a vehicle with an assistance system 10 which is set up to detect a line of sight of the driver and to initiate further steps depending thereon. By way of example, the determined viewing direction can be used to monitor the driver's attention and, if necessary, to issue warnings. Alternatively or additionally, the determined viewing direction can be used to selectively activate additional functions of the vehicle.

The assistance system 10 includes a sensor unit (not shown in detail) with a camera, which is arranged and arranged facing the driver, a viewing direction 2 and head position 3 to capture the driver, for example, based on the eye and / or pupil position. The sensor unit may also include an optional lighting device. The sensor unit may also be referred to as an eye tracking system (ETS).

The assistance system 10 further comprises a control unit (not shown in detail), a projection device 13 and / or a marker 14 ,

At the projection device 13 this is a laser that is set up, a point 4a to illuminate on the road at a given distance to the vehicle (dotted-dashed line in 1 ). Alternatively or additionally, the vehicle may be the marker 14 have, for example, the foldable or extendable on the hood at one point 4b can be arranged at a predetermined distance from the driver.

The control unit may in particular have a data and program memory in which a program for operating the assistance system 10 which is based on the flowchart of the 2 is explained in more detail below.

The program will be in one step S1 started, in which, for example, variables are initialized. In the present embodiment, the program is in one step S3 continued. In alternative embodiments, the program may also be in one step S5 or S7 to be continued.

In the step S3 becomes the projection device 13 or a marker 14 assigned movement mechanism driven, the predetermined point 4a respectively. 4b for the driver to emphasize, so a radiation-emitting operation of the projection device 13 activated or the marker 14 unfolded or extended. The program is in the present embodiment in the step S5 continued, in other embodiments, the program can also in the step S7 to be continued.

In the step S5 the driver is prompted for the highlighted point 4a . 4b to focus, exemplified by corresponding audio signal and / or visual representation. The program will then be in the step S7 continued.

In the step S7 become coordinates of the projected point 4a or the unfolded or extended marker 14 at the point 4b provided as a reference characteristic. The relative position of the point 4a . 4b to the camera coordinate system or vehicle coordinate system is therefore known. In other embodiments, the point may also be in the vehicle interior.

In addition, an initial direction characteristic Ri and an initial position characteristic value P _i determined. The directional characteristic Ri is representative of the viewing direction 2 the driver. The position characteristic Pi is representative of the head position 3 the driver. Furthermore, in the step S7 determines a calibration characteristic Ki which is representative of a vector representing the head position 3 with the point 4a . 4b combines.

A ray of eye from the driver who points the point 4a . 4b focused, can be described by a three-dimensional Aufvektor, for example, the position of a Cyclops in a coordinate system, such as the vehicle coordinate system, and a three-dimensional direction vector. The sensor unit can measure the measured viewing direction 2 also provide the driver in the form of a measured three-dimensional Aufvektors as position characteristic Pi and a measured three-dimensional direction vector as a directional characteristic Ri.

By means of the position of the cyclopedo (measured up-vector) and the actual position (coordinates of the point 4a . 4b) the calibration characteristic Ki can be determined.

The program will then be in one step S9 continued.

In the step S9 a geometric transformation is determined as a transformation characteristic value T between the direction characteristic value Ri, that is to say a measured perspective vector, and the calibration characteristic value Ki.

In particular, the transformation is a rigid transformation, e.g. can be described as a transformation characteristic value T by a homogeneous 4 × 4 transformation matrix. The transformation matrix describes the transformation between the calibration characteristic Ki and the measured line of sight vector represented by the directional characteristic Ri.

In this embodiment, the step S7 initially repeated until a predetermined number N of measurements has been performed. In the case that the predetermined number N of measurements has been reached, becomes dependent on the determined directional characteristics R ₁ ... R _N and the determined calibration characteristics K ₁ ... K _N determines a transformation that is a deviation between the measured directional characteristics R ₁ ... R _N the calibration characteristics K ₁ ... K _N minimized. In other embodiments, only one measurement can be performed without the program in the step S7 to repeat (N = 1).

The transformation characteristic value T can then be stored for the corresponding driver and the program can be ended. Alternatively, the program can then also in one step S11 to be continued.

In the step S11 the transformation characteristic value T is provided for the corresponding driver. Furthermore, a new directional characteristic is added R _new and position characteristic P _new determined. Depending on the transformation characteristic T and the new directional characteristic R _new and position characteristic P _new then becomes a corrected directional characteristic R _corrected determined. The corrected directional characteristic R _corrected is in particular representative of a driver's sight line compensated for the unknown, individual eye geometry of the driver.

In other words, for all future measurements provided by the sensor unit, the measured directional characteristic R _i be corrected with the transformation characteristic value T. In the case of a homogeneous 4 × 4 transformation matrix, this would correspond to a matrix-vector multiplication of the transformation characteristic value T with a homogeneous vector, the directional characteristic Ri.

The program can subsequently be in one step S13 be continued, depending on the corrected directional characteristic R _corrected a control signal for operating further functions of the vehicle is determined. The program will be terminated afterwards.

LIST OF REFERENCE NUMBERS

2

line of sight

3

head position

4a, 4b

given point

10

assistance system

13

projection device

14

marker

15

projection

S1 ... S13

program steps

Claims (9)

A method for operating an assistance system (10) for a vehicle, comprising a sensor device for determining a direction characteristic which is representative of a viewing direction (2) of a driver of the vehicle, and for determining a position characteristic value which is representative of a head position (3) of the vehicle Driver, taking in the process providing a reference characteristic which is representative of coordinates of a point (4a, 4b) predetermined in relation to the vehicle in three-dimensional space, at least one initial directional and position characteristic value is determined, depending on the at least one initial position characteristic value and the reference characteristic value, a calibration characteristic value is respectively determined which is representative of a vector which connects the head position (3) to the point (4a, 4b), depending on the at least one initial directional characteristic value and the respective calibration characteristic value, a transformation characteristic value is determined which is representative of a geometric transformation between the at least one initial directional parameter and the respective calibration parameter, and - Depending on the transformation characteristic value, subsequently determined directional and position characteristic values are corrected. Method according to Claim 1 in which, before determining the at least one initial heading and position characteristic value, the driver is requested by the driver to focus the predetermined point. Method according to one of the preceding claims, wherein the assistance system comprises a projection device (13), and in the method before determining the at least one initial direction and position characteristic value, the projection device is driven to irradiate the predetermined point. Method according to one of the preceding claims, wherein the assistance system comprises a movement mechanism and a marker, wherein the movement mechanism is adapted to move the marker from a neutral position to the predetermined point and back, and in the method before determining the at least one initial direction and position characteristic of the movement mechanism is driven such that the marker is moved to the predetermined arranged point. An assistance system (10) for a vehicle, comprising - a sensor device for determining a direction characteristic which is representative of a viewing direction (2) of a driver of the vehicle, as well as for determining a position characteristic representative of a head position (3) of the driver, and a control unit which is set up the method according to one of Claims 1 to 4 perform. Assistance system (10) after Claim 5 comprising a projection device (13), the is set up to irradiate a point arranged in a predetermined manner relative to the vehicle in three-dimensional space. Assistance system (10) after Claim 5 or 6 , comprising a movement mechanism and a marker (14), wherein the movement mechanism is arranged to move the marker from a neutral position to the point arranged in relation to the vehicle and back. Computer program for operating an assistance system (10), wherein the computer program is designed, a method according to one of Claims 1 to 4 when executed on a data processing device. Computer program product comprising executable program code, wherein the program code when executed by a data processing device, the method according to one of Claims 1 to 4 performs.

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