FR3083907A1 - DEVICE FOR MONITORING AN OCCUPANT OF A MOTOR VEHICLE - Google Patents

Abstract

The invention relates to a monitoring device (DISP) comprising: a camera (Cam) configured to acquire images of a physical part (T) of an occupant and comprising a primary sensor (C1) configured to determine a primary inclination ( α1) of said camera with respect to an earth frame of reference (Tref); - a secondary sensor (C2) disposed in said passenger compartment (H) and configured to determine a secondary inclination (a2) of said passenger compartment (H) relative to an earth frame of reference (Tref); - a computer (Dms) configured to: - calculate a tertiary inclination (a3) of said camera with respect to a vehicle reference system as a function of the primary and secondary inclinations; - determining a quaternary inclination (a4) of said physical part with respect to said vehicle reference system as a function of said images and of said tertiary inclination; - execute a function as a function of said quaternary tilt.

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a device for monitoring an occupant of a motor vehicle comprising a passenger compartment. The invention also relates to a camera for a motor vehicle comprising a primary sensor. Finally, the invention also relates to a method for monitoring an occupant of a motor vehicle.

It finds a particular but non-limiting application in motor vehicles.

TECHNOLOGICAL BACKGROUND OF THE INVENTION

A device for monitoring an occupant of a motor vehicle comprising a passenger compartment comprises, in a manner known to those skilled in the art, a camera configured to acquire images of a physical part of an occupant. The eyes form the physical part and the occupant is the driver of the motor vehicle. The position of the driver's seat or the mirrors is adjusted according to the height of the eyes in a motor vehicle reference system.

A drawback of this prior art is that the camera is positioned on the top module of the steering column of the motor vehicle. Unfortunately, in many cockpits, this part is mobile for the height adjustment of the steering wheel in order to adapt to its driver. Thus, the camera, becoming movable relative to the passenger compartment, it is no longer possible to know its position in the motor vehicle reference system and therefore, the height of the eyes in the motor vehicle reference system.

In this context, the present invention aims to propose a device for monitoring an occupant of a motor vehicle which makes it possible to solve the mentioned drawback.

GENERAL DESCRIPTION OF THE INVENTION

To this end, the invention provides a device for monitoring an occupant of a motor vehicle comprising a passenger compartment, said monitoring device comprising a camera configured to acquire images of a physical part of said occupant, characterized in that:

said camera comprises a primary sensor configured to determine a primary inclination of said camera relative to an earth frame of reference

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- said monitoring device also comprises:

- A secondary sensor arranged in said passenger compartment and configured to determine a secondary inclination of said passenger compartment relative to an earth referential;

- a computer configured for:

- calculating a tertiary inclination of said camera relative to a vehicle reference system as a function of said primary inclination and said secondary inclination;

- determining a quaternary inclination of said physical part of said occupant with respect to said vehicle reference system as a function of said acquired images and of said tertiary inclination;

- execute a function as a function of said quaternary tilt.

Thus, as will be seen in detail below, by adding a local sensor to the camera, this makes it possible to always know the position of the camera relative to the earth frame of reference. Furthermore, by combining this information with that of a secondary sensor disposed in the motor vehicle, it is possible to deduce the position of the camera in the motor vehicle reference frame and thus to be able to deduce from the images of the camera the inclination in three directions of the physical part of said occupant in the vehicle repository.

According to nonlimiting embodiments, said device for monitoring an occupant of a motor vehicle may further include one or more additional characteristics among the following:

According to a nonlimiting embodiment, said physical part of said occupant is his head or his eyes.

According to a nonlimiting embodiment, said primary sensor and said secondary sensor comprise an accelerometer or a gyroscope.

According to a nonlimiting embodiment, said tertiary inclination is equal to the difference between said secondary inclination and said primary inclination.

According to a nonlimiting embodiment, said quaternary inclination forms a monitoring parameter.

According to a nonlimiting embodiment, said monitoring parameter is an inclination of the head, a height of the head, a height of the eyes, or a direction of the eyes.

According to a nonlimiting embodiment, said function is a comfort function or the emission of an alert signal.

There is also proposed a camera for a motor vehicle configured to acquire images of a physical part of an occupant of said motor vehicle, according to which said camera comprises a primary sensor configured to determine a primary inclination of said camera relative to an earth frame of reference. .

According to a nonlimiting embodiment, said primary sensor comprises an accelerometer or a gyroscope.

Finally, a method of monitoring an occupant of a motor vehicle comprising a passenger compartment is also proposed, said monitoring method comprising the acquisition by images by a camera of a physical part of said occupant, characterized in that said monitoring method further comprises:

- the determination by a primary sensor of said camera of a primary inclination of said camera relative to an earth frame of reference;

- the determination by a secondary sensor arranged in said passenger compartment of a secondary inclination of said passenger compartment relative to said earth frame of reference;

- the calculation by a computer of a tertiary inclination of said camera relative to a vehicle reference system as a function of said primary inclination and said secondary inclination;

- the determination by said computer of a quaternary inclination of said physical part with respect to said vehicle reference system as a function of said acquired images and of said tertiary inclination;

- the execution by said computer of a function as a function of said quaternary inclination.

BRIEF DESCRIPTION OF THE FIGURES

The invention and its various applications will be better understood on reading the description which follows and on examining the figures which accompany it:

- Figure 1 schematically shows a device for monitoring an occupant of a motor vehicle, said monitoring device comprising a camera with a primary sensor, a secondary sensor, and a computer, according to a non-limiting embodiment of the invention;

- Figure 2 shows schematically in a simplified 2D view, the elements of the monitoring device of Figure 1 in the motor vehicle, according to a non-limiting embodiment;

- Figure 3 shows in a simplified 2D view, a primary tilt of the camera in the ground frame, a secondary tilt of the passenger compartment of the motor vehicle in the same ground frame, and a tertiary tilt of the camera in the frame of reference , according to a nonlimiting embodiment;

- Figure 4 shows in a simplified schematic view in 2D said camera of Figures 1 and 2 equipped with a primary sensor and in three different positions depending on a support on which it is fixed, according to a non-limiting embodiment;

- Figure 5 shows in a simplified 2D view, a quaternary tilt that can take the physical part of an occupant in the vehicle repository, according to a non-limiting embodiment;

- Figure 6 shows a method of monitoring an occupant of a motor vehicle implemented by the monitoring device of Figure 1, according to a non-limiting embodiment of the invention.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Identical elements, by structure or by function, appear in the different figures keep, unless otherwise specified, the same references.

The device DISP for monitoring an occupant O of a motor vehicle according to the invention is described with reference to FIGS. 1 to 5.

By motor vehicle is meant any type of motor vehicle.

In a nonlimiting embodiment, an occupant O of a motor vehicle V is the driver of said motor vehicle V.

As illustrated in Figures 1 and 2, the DISP monitoring device includes:

- a camera comprising a primary sensor C1;

- a secondary sensor C2;

- a Dms computer.

The elements of the DISP monitoring device are described in detail below.

• Cam camera

The camera is illustrated in Figures 1,2, 4 and 5.

She understands :

- an optical objective Ob which cooperates with an image acquisition sensor (not shown) to capture images I;

a communication module Tx between said camera Cam and said at least one computer Dms of the motor vehicle V;

- a primary sensor C1.

As illustrated in FIG. 2, the camera Cam is located in the passenger compartment H of the motor vehicle V.

It is secured to the part of the steering column located in the passenger compartment H of the motor vehicle V, namely the top column module Col, also called top column Col.

The column top Col is configured to be adjusted in the passenger compartment H. For this purpose, it is configured to pivot in the vertical plane oriented in the longitudinal direction of the motor vehicle V. Consequently, the Cam camera which is secured to said top Col column moves in the same way.

The camera Cam is configured to acquire images I of a physical part T of said occupant O (function illustrated in FIG. 1 ACQ (Cam, I, T (O));

Its optical objective Ob is oriented towards said physical part T of said occupant O so that its image acquisition sensor can acquire said images I. Once acquired, said images I are transferred by the communication module Tx to the computer Dms to be exploited.

It will be noted that its position on the top of the column Col allows it to acquire images I of the head or of the eyes of the conductor O for example.

Thus, in nonlimiting embodiments, the physical part of said occupant O is his head or his eyes.

In another nonlimiting embodiment, the physical part T of said occupant O is his body.

o Primary sensor C1

The primary sensor C1 is illustrated in Figures 1,2, 4 and 5.

The primary sensor C1, which is secured to the camera Cam, is configured to determine a primary inclination a1 of said camera Cam with respect to a Tref earth frame of reference illustrated in FIG. 2 (function illustrated in FIG. 1 DET (C1, a1, Cam, Tref)).

In a nonlimiting embodiment, the Earth reference Tref is the center of the earth.

In the nonlimiting example illustrated, said primary inclination a1 is the angle formed by the increase in the axis of the camera Cam with the plane perpendicular to the terrestrial vertical Z.

Thus, when the top of column Col is set in motion to be adjusted as a function of the occupant O of the motor vehicle V which is here the driver, said primary inclination a1 will change value.

In a nonlimiting embodiment, the primary sensor C1 determines said primary inclination a1 when the motor vehicle V is at rest or is traveling at constant speed to avoid distorting the calculation by the acceleration of the motor vehicle V.

In a nonlimiting embodiment, said primary sensor C1 is a tilt sensor. In a nonlimiting alternative embodiment, said primary sensor C1 comprises an accelerometer or a gyroscope.

Technologies which use an accelerometer or a gyroscope make it possible to locate in a manner known to those skilled in the art the terrestrial vertical Z based on the terrestrial gravity force and make it possible to detect rotational movements in three dimensions. Accelerometers measure the gravity vector on three axes. We can thus find an inclination in the three directions X, Y and Z, from the gravity vector.

As illustrated in FIG. 4, in a diagram reduced to 2 dimensions for reasons of simplification, where g is the gravity vector, the coordinates Gz, Gx of the camera Cam along the axis Z1 and the axis X1 in a camera repository when projected on the terrestrial vertical Z are the following:

- For case 1: Gz = -g cos (0) = -g, Gx = -g x sin (0) = 0,

- For case 2: Gz = -g x cos (a1), Gx = -g x sin (a1),

- For case 3: Gz = -g x cos (-a1) = -g x cos (a1), Gx = g x sin (a1). As can be seen, depending on the position of the top of column Col, the Cam camera has different coordinates in the Tref terrestrial frame of reference.

When the primary a1 tilt has been determined, the Tx communication module transmits its value to the Dms computer (function not shown).

It will be noted that the nonlimiting example taken for the primary inclination a1 is the angle of increase relative to the terrestrial vertical Z. However, the description above also applies to the two other directions X and Y.

• Secondary sensor C2

The secondary sensor C2 is illustrated in FIGS. 1, 2 and 5. It is arranged in the passenger compartment H of the motor vehicle V.

The secondary sensor C2 is configured to determine a secondary inclination a2 of said passenger compartment H relative to the ground reference frame Tref (function illustrated in FIG. 1 DET (C2, a2, H, Tref)).

In the nonlimiting example illustrated in FIG. 2, the secondary inclination a2 is the angle of rise of the floor of the passenger compartment H with the plane perpendicular to the terrestrial vertical Z.

In a nonlimiting embodiment, the secondary sensor C2 determines said secondary tilt a2 when the motor vehicle V is at rest or is moving at constant speed to avoid distorting the calculation by the acceleration of the motor vehicle V.

In a nonlimiting embodiment, the secondary sensor C2 is a sensor already present in the motor vehicle V and used for other functions than monitoring. For example, it can be used for the ABS anti-lock system functionality or for the ESP trajectory correction functionality. Thus, a sensor already present in the passenger compartment H can be used to determine the position of the passenger compartment H relative to the Tref earth frame of reference.

If such a sensor is not present or available, in another nonlimiting embodiment not illustrated, the secondary sensor C2 can be placed in the Dms computer, given that the latter is fixed relative to the passenger compartment H .

In a nonlimiting embodiment, said secondary sensor C2 is a tilt sensor. In a nonlimiting alternative embodiment, said secondary sensor C2 comprises an accelerometer or a gyroscope.

When the secondary tilt a2 has been determined, the communication module Tx transmits the value of the secondary tilt a2 to the computer Dms (function not shown).

As described below, with the two values of primary tilt a1 (Cam camera versus Tref ground frame) and secondary tilt a2 (habitable H versus Tref ground frame), it is possible to find the position of the Cam camera by compared to the habitable H.

It will be noted that the nonlimiting example taken for the secondary inclination a2 is the angle of increase relative to the terrestrial vertical Z. However, the description above also applies to the two other directions X and Y.

• Dms calculator

The Dms computer is illustrated in Figures 1,2 and 5.

It is arranged in the motor vehicle V and cooperates with the camera Cam. In a nonlimiting embodiment, the Dms computer is remote from the Cam camera. It is indeed too bulky to be placed near the steering wheel on the top of column Col. In a nonlimiting embodiment, it is arranged under the dashboard of the motor vehicle V.

The Dms computer is configured for:

- calculate a tertiary inclination a3 of said camera Cam relative to a vehicle reference frame Vref as a function of said primary inclination a1 and said secondary inclination a2 (function illustrated in FIG. 1 CALC (Dms, α3 (α2, α1), Cam) ;

- determine a quaternary inclination a4 of said physical part T of said occupant O with respect to said vehicle reference frame Vref as a function of said acquired images I and of said tertiary inclination a3 (function illustrated in FIG. 1 DET (Dms, α4 (α3, I)) ;

- execute a function Ft as a function of said quaternary tilt a4 (function illustrated in FIG. 1 EXEC (Dms, Ft (a4))).

As described above, in nonlimiting embodiments, said physical part T of said occupant O to be monitored is his head or his eyes. By monitoring at least one of these physical parts T, this makes it possible to detect attitudes of inattention and thus to be able, by appropriate actions, to avoid an accident for example.

In the nonlimiting example illustrated in FIG. 3, the tertiary inclination a3 is the angle of increase of the camera Cam in the vehicle reference frame Vref. The Dms calculator calculates it by making the difference between the primary tilt a1 and the secondary tilt a2. As illustrated in Figure 3, a3 = α1 - a2.

It will be noted that the inclinations a1 to a3 are calculated in particular when the motor vehicle V is traveling and the images I are acquired in particular also when the motor vehicle V is traveling. Thus, the angle correction a3 is applied in particular when the motor vehicle V is traveling so as to obtain the quaternary inclination a4.

The quaternary inclination a4 (illustrated in FIG. 5) is the angle of inclination of said physical part T of said occupant O expressed in the frame of reference Vref.

It is calculated by said computer Dms taking into account the images I acquired and the position of the camera Cam in the vehicle reference frame Vref (tertiary tilt a3).

From the images I acquired, the computer Dms determines the physical part T to be monitored and its inclination (not shown) in a camera frame of reference (not shown). This determination being known to the skilled person, it is not described here.

It will be noted that the images I used by the computer Dms are the images I transferred by the communication module Tx of the camera Cam, or a part of the images I transferred. For example, the images I acquired and transferred can be that of the head, and the images used can be those of the eyes if the physical part T to be monitored is only the eyes, for example. The computer Dms thus uses all or part of the images I acquired.

The tertiary tilt a3 represents an angle correction. Thanks to the tertiary inclination a3, the inclination of the physical part T determined in the camera frame of reference is brought back into the vehicle frame of reference Vref. This gives the inclination a4 of the physical part T that we want to monitor relative to the vehicle reference frame Vref.

The quaternary inclination a4 forms a monitoring parameter Ps of the physical part T. In nonlimiting embodiments, the monitoring parameter Ps is an inclination of the head, a height of the head, an eye height or a direction eyes. Indeed, the quaternary tilt a4 is determined according to the X, Y or Z axes taken alone or in combination.

It will be noted that the nonlimiting example taken for the quaternary inclination a4 is the angle of increase relative to the terrestrial vertical Z. However, the description above also applies to the two other directions X and Y.

The computer Dms thus takes into account the quaternary tilt a4 in the three directions X, Y and Z taken individually or in combination, depending on the function Ft to be executed. Thus, for a function Ft of backlighting of the car radio, we know that it is necessary to take into account the monitoring parameter Ps which is the direction of the eyes in a nonlimiting example. Therefore the quaternary tilt a4 in the three directions X, Y and Z is determined.

Thus, once said quaternary tilt a4 calculated, according to the value it takes, said computer Dms executes a function Ft or not.

In a nonlimiting embodiment, said function Ft is a comfort function or the emission of an alert signal. This allows you to anticipate possible security problems or it allows you to perform certain actions that the user wishes to do.

In a nonlimiting example, the physical part T of said occupant O is his eyes and the monitoring parameter Ps is the direction of the eyes, namely of his gaze. In this case, when it points towards the car radio, the Ft function is to switch on the car radio or increase its backlight. This applies to any other combination of instruments in the motor vehicle V such as a speedometer or any other multimedia system.

In another nonlimiting example with the direction of his gaze, when the direction of gaze no longer points towards the road, the computer Dms deduces that said occupant O is no longer attentive to the road, and the function Ft is the sending an alert message which is an audible signal in a nonlimiting example. In another nonlimiting example, the physical part T of said occupant O is his eyes and the monitoring parameter Ps is the height of the eyes. In this case, depending on the height of the eyes, the function Ft is the adjustment of the position of the seat in height, or even of the mirrors.

In another nonlimiting example, the physical part T of said occupant O is its head and the monitoring parameter Ps is the inclination of the head. In this case, depending on the tilt of the head, the Ft function is the sending of an alert message which is an audible signal in a non-limiting example. This is used for drowsiness in a nonlimiting example.

In a nonlimiting embodiment, the quaternary inclination a4 of a single physical part T is determined.

In another nonlimiting embodiment, the quaternary inclination a4 of several physical parts T can be determined.

It will be noted that several monitoring parameters Ps can be taken into account, whether for a single physical part T or for several physical parts T.

Thus, the monitoring device DISP makes it possible to implement a method for monitoring PR of an occupant O of a motor vehicle V comprising a passenger compartment H, illustrated in FIG. 6, according to a non-limiting embodiment.

The PR process includes:

- in step E1), the acquisition of images I by the camera Cam of a physical part T of said occupant O;

- in step E2), the determination by the primary sensor C1 of said camera Cam of a primary inclination a1 of said camera Cam with respect to an earth frame of reference Tref;

- in step E3), the determination by the secondary sensor C2 disposed in said passenger compartment H of a secondary inclination a2 of said passenger compartment H relative to said Earth reference frame Tref;

- in step E4), the calculation by the computer Dms of a tertiary inclination a3 of said camera Cam relative to a vehicle frame of reference Vref as a function of said primary inclination a1 and said secondary inclination a2;

- in step E5), the determination by said computer Dms of a quaternary inclination a4 of said physical part T relative to said vehicle frame of reference Vref as a function of said acquired images I and of said tertiary inclination a3;

- in step E6), the execution by said computer Dms of a function Ft as a function of said quaternary inclination a4.

Of course, the description of the invention is not limited to the embodiments described above.

Thus, in other nonlimiting embodiments, the Cam camera can be arranged:

- In a pillar of the motor vehicle V, occupant side O, which is a part of the bodywork under the door trim, for example;

- in the center console of the dashboard of motor vehicle V, near the windshield.

Thus, in another embodiment, the physical part T of the occupant O is his body and the monitoring parameter Ps is a position of the body. Thus, in another embodiment, the occupant O of the motor vehicle V is a passenger. In a nonlimiting variant, the passenger is the front passenger.

Thus, the invention described has the following advantages in particular:

- it is simple to implement;

- it makes it possible to precisely determine whether the driver is distracted or to act on multimedia systems or any other combined instrument of the motor vehicle;

- it can be implemented in autonomous vehicles;

- it makes it possible to reduce the CPU costs at the level of the computer Dms, since the latter does not have to calculate the quaternary tilt a4 directly from the images I acquired from the camera Cam as a function of points presumedly fixed in the motor vehicle V ;

- it makes it possible to reduce costs on the manufacturer side since it does not have to install a primary sensor directly in motor vehicles;

- there are no constraints on the manufacturer side to integrate a primary sensor C1, since the Cam camera is a product independent of the motor vehicle V;

- It makes it possible to reduce the diversity of assembly of motor vehicles V for an automobile manufacturer since the latter having no primary sensor to assemble in the motor vehicle itself, it will not need to implement two lines of dedicated assemblies, one dedicated to motor vehicles which have the option of monitoring device with a dedicated mechanical element for the primary sensor, and the other dedicated to motor vehicles without the option of monitoring device and therefore without a primary sensor to be assembled and without a dedicated mechanical element for such a primary sensor.

Claims (10)

1. Device for monitoring (DISP) an occupant (O) of a motor vehicle (V) comprising a passenger compartment (H), said monitoring device (DISP) comprising a camera (Cam) configured to acquire images (I ) a physical part (T) of said occupant (O), characterized in that: - said camera (Cam) comprises a primary sensor (C1) configured to determine a primary inclination (a1) of said camera (Cam) relative to an earth frame of reference (Tref); - said monitoring device (DISP) further comprises: - a secondary sensor (C2) disposed in said passenger compartment (H) and configured to determine a secondary inclination (a2) of said passenger compartment (H) relative to an earth frame of reference (Tref); - a computer (Dms) configured for: - calculating a tertiary tilt (a3) of said camera (Cam) relative to a vehicle frame of reference (Vref) as a function of said primary tilt (a1) and said secondary tilt (a2); - determining a quaternary inclination (a4) of said physical part (T) of said occupant (O) relative to said vehicle reference system as a function of said acquired images (I) and of said tertiary inclination (a3); - execute a function (Ft) as a function of said quaternary tilt (a4). 2. Monitoring device (DISP) according to claim 1, wherein said physical part (T) of said occupant (O) is his head or his eyes. 3. Monitoring device (DISP) according to claim 1 or claim 2, wherein said primary sensor (C1) and said secondary sensor (C2) comprise an accelerometer or a gyroscope. 4. Monitoring device (DISP) according to any one of the preceding claims, according to which said tertiary inclination (a3) is equal to the difference between said secondary inclination (a2) and said primary inclination (a1). 5. Monitoring device (DISP) according to any one of the preceding claims, according to which said quaternary inclination (a4) forms a monitoring parameter (Ps). 6. Monitoring device (DISP) according to claim 5, according to which said monitoring parameter (Ps) is an inclination of the head, a height of the head, a height of the eyes, or a direction of the eyes. 7. Monitoring device (DISP) according to any one of the preceding claims, according to which said function (Ft) is a comfort function or the emission of an alert signal. 8. Camera (Cam) for a motor vehicle (V) configured to acquire images (I) of a physical part (T) of an occupant (O) of said motor vehicle (V), according to which said camera (Cam) comprises a primary sensor (C1) configured to determine a primary inclination (a1) of said camera (Cam) relative to an earth frame of reference (Tref). 9. Camera (Cam) according to claim 6, wherein said primary sensor (C1) comprises an accelerometer or a gyroscope. 10. Monitoring method (PR) of an occupant (O) of a motor vehicle (V) comprising a passenger compartment (H), said monitoring method (PR) comprising the acquisition of images (I) by a camera (Cam) of a physical part (T) of said occupant (O), characterized in that said monitoring method (PR) further comprises: - the determination by a primary sensor (C1) of said camera (Cam) of a primary tilt (a1) of said camera (Cam) relative to an earth frame of reference (Tref); - the determination by a secondary sensor (C2) arranged in said passenger compartment (H) of a secondary inclination (a2) of said passenger compartment (H) relative to said earth frame of reference (Tref); - the calculation by a computer (Dms) of a tertiary tilt (a3) of said camera (Cam) relative to a vehicle frame of reference (Vref) according to said primary tilt (a1) and said secondary tilt (a2); the determination by said computer (Dms) of a quaternary tilt (a4) of at least one monitoring parameter (Ps) of said physical part (T) of said occupant (O) with respect to said vehicle reference system as a function of said images ( I) acquired and of said tertiary inclination (a3); - the execution by said computer (Dms) of a function (Ft) as a function of said quaternary tilt (a4).