WO2008071601A1

WO2008071601A1 - Method and device for detecting bodies on the trajectory of an opening and vehicle provided with said device

Info

Publication number: WO2008071601A1
Application number: PCT/EP2007/063296
Authority: WO
Inventors: Sébastien CORNOU; Didier Wautier
Original assignee: Renault S.A.S
Priority date: 2006-12-13
Filing date: 2007-12-04
Publication date: 2008-06-19
Also published as: FR2910045A1; EP2102441A1; FR2910045B1

Abstract

The invention relates to a powered detection device for an automotive vehicle. According to the invention, a camera (6) is provided for surveying the opening (1), lighting means (8) for generating a predetermined pattern (82) of luminous marks (80) that can be viewed through the camera (6), means for searching the pattern (82) of luminous marks (80) in a current image of the camera (6) in order to determine the presence of a foreign body on the trajectory of the opening (1) if the pattern (82) of luminous marks (80) has not been found therein.

Description

Device and method for detecting a body on the stroke of an ouyrant, vehicle equipped with the device

The invention relates to a device and a method for detecting a foreign body on the stroke of a motorized opening of a motor vehicle.

A field of application of the invention is generally the control on the vehicle of an opening such as for example a sliding side door or a tailgate.

The motorization of the opening allows to dispense with the muscular force of a person for their maneuver, which is advantageous when these doors are heavy as for example the sliding side doors. In addition, the motorization allows an easy and fast maneuver.

However, there is a potential risk of injury to persons in the event of impact with the moving sash or jamming between the sash and a fixed element of the vehicle, such as for example a center pillar, the opening of the frame. opening.

Currently, two systems are used to prevent such accidents on sliding side doors.

The first system consists of an anti-pinch joint disposed on the edge of the door, to detect the presence of an obstacle between the door and the fixed part of the vehicle when closing the door. This system implies that a large force, greater than 100 N, is applied by the obstacle on the joint. In addition, given the inertia of the door, the stop is not immediate, which may hurt a person obstructing despite the presence of the anti-pinch seal. The second system consists of a control of the current demanded from the electric motor during the closing of the door in order to determine whether an external element such as an obstacle or seizure interferes with the movement of the door. The problem of these two systems is that they detect the presence of the obstacle only when contact with it.

Thus, it seeks a device and a foreign object detection method in the race of a motorized motor vehicle opening, which are particularly suitable for the forms of opening and opening used in the automotive industry, which are three-dimensional ( left or curved, for example) and complicated, without presenting flat edges and / or having races not strictly rectilinear. Thus, the sliding side doors of motor vehicles are not retractable and have a non-rectilinear stroke between the fully open position and the total closed position, with in particular a trajectory returning towards the inside of the vehicle during the total closure to fit the three-dimensional profile of the bodywork surrounding the opening.

The invention aims to solve this problem and to obtain a device and a detection method for detecting the presence of a potential obstacle or more generally of a foreign object on the trajectory of the motorized opening of the motor vehicle, so as to ability to adapt its speed and possibly stop it if detected.

For this purpose, a first object of the invention is a device for detecting a foreign body on the stroke of a motorized opening of a motor vehicle, the opening being movable relative to a fixed part of the vehicle between one and the other of a first position and a second position, characterized by at least one surveillance camera of at least a portion of the zone occupied by the opening between its first and second position, means lighting, able to produce a prescribed pattern of light cues observable in said area portion by the camera, search means of the light cue pattern in at least one current image of the camera, to determine, in the case where the pattern of luminous landmarks was not found in the current image of the camera, the presence of a foreign body on the stroke of the opening. According to other features of the invention,

the search means comprise means for comparing the image of the camera with a set of predetermined reference images of the camera for predetermined positions of reference of the opening in its race, for determining said presence of the foreign body in the case where the current image of the camera does not correspond to any reference image;

the search means comprise means for estimating the position of the opening for the current image as being the reference position associated with the reference image closest to the current image;

the search means comprise means for estimating, in the case where the current image of the camera does not correspond to any reference image, the position of the foreign body for the current image by analyzing the differences between the reference image the closest to the current image and the current image;

the camera and the lighting means are oriented in the direction of travel of the opening between one and the other of its first position and its second position, the camera and the lighting means are arranged relative to each other so that the light marks are in variable positions in the image of the camera according to the position of the opening in its race between the one and the other of its first position and second position;

- The camera and the lighting means are both located on the same element selected from the opening and the fixed part of the vehicle and are arranged so that the pattern of light marks is projected at least in part by the lighting means on the other element among the opening and the fixed part of the vehicle;

- Or the camera is located on a selected element among the opening and the fixed part of the vehicle, the lighting means are located on the other element among the opening and the fixed part of the vehicle and comprise a plurality of localized light sources each producing a luminous landmark of the pattern.

A second object of the invention is a method for detecting a foreign body on the stroke of a motorized opening of a motor vehicle using the device as described above, the opening being movable relative to to another part of the vehicle between one and the other of a first position and a second position, characterized in that the pixels of at least one current image of the camera are summed in a first direction prescribed according to the prescribed pattern of luminous markings of the illumination means, so as to calculate a signature of the current image of the camera in a second direction orthogonal to the first prescribed direction, the signature is quantified, the quantified signature is compared to a set of reference signatures determined for a set of predetermined camera reference images for predetermined reference positions of the opening in its race, to determine ite presence of the foreign body in the case where the quantized signature does not correspond to any reference signature.

According to one characteristic of the invention, the quantization step is preceded by a step of differentiating successive signatures to provide a differential signature, the quantization step and the comparison step being performed on said differential signature. A third object of the invention is a motor vehicle, comprising a motorized opening, movable relative to a fixed part of the vehicle between one and the other of a first position and a second position, control means movement of the opening in the direction of closure between the first position and the second position, characterized in that it is provided with the device for detecting a foreign body on the stroke of the opening as described herein below. above, and means stopping said closing movement of the opening in the case where a foreign body is detected on the opening of the opening by said device.

The invention will be better understood on reading the description which follows, given solely by way of non-limiting example with reference to the accompanying drawings, in which:

FIG. 1 schematically represents a view of the external side of a motor vehicle provided with a sliding side door and of the detection device according to the invention,

FIG. 2 is a schematic perspective view of an exemplary light marker pattern used in one embodiment of the device according to the invention,

- Figures 4 to 9 show different image signatures processed in the device according to the invention. FIG. 1 shows the side of a motor vehicle V, comprising as opening a sliding side door 1 in a fully open position, an opening 2 of the vehicle to be closed by the door 1, and a body 3 having the opening 2 and supporting door 1. Of course, in what follows, the term door can be replaced by opening 1. In fully open position, or intermediate between the fully open position and the closed position, the door 1 is in front of the bodywork 3, c that is, outside of it. In the fully open position, a passage P is delimited between an edge 10 of the door 1 and an edge 20 of the opening 2, to enter and exit the vehicle V. Although represented by a rectangle in Figure 1, the door 1 has a curved shape, the opening 2 also has a complementary curved shape and the edges of the door are curved, as shown in the example of Figure 2.

In FIG. 2, the vehicle V comprises a motor 4 for mechanically driving the opening or door 1 in a prescribed path between the one and the other of the fully open position and the fully closed position in the opening 2. A manual means 5 is provided for allow a user to control the engine 4 via a computer 7 and a link 12 between the computer 7 and the engine 4, in order to close or open the door 1. In the case of the side door sliding 1, the door 1 is guided in a race having a main component in translation in the longitudinal direction L of the vehicle.

During its travel between the fully open position and the closed position, the opening 1 occupies an area 1 1 of the space, formed in Figure 1 by the passage P between the edge 10 of the door and the edge 20 opening 2. A camera 6 is mounted on the vehicle V to target the zone 1 1 of the opening 1. The camera 6 advantageously allows to observe a wide area. The field of view of the camera 6 may also be limited to a part of the zone 1 1, for example between two intermediate positions between the fully open position and the closed position and / or on part of the edge 10. generally, the camera 6 makes it possible to observe the zone 11 for the opening 1 located between a first position and a second position, these first and second positions being respectively the fully open position and the fully closed position or intermediate positions. In the embodiment of FIG. 1, the camera 6 is oriented substantially in the same longitudinal direction L as the stroke of the sliding door 1 between the fully open position and the closed position.

In the embodiment of FIG. 1, the camera 6 is provided on the fixed part of the vehicle, with respect to which the opening 1 is movable, this fixed part being for example formed by the passenger compartment of the vehicle comprising the opening 2. For example, the camera is positioned at the pedestrian level in the upper corner of the frame 2 of the door and has a field of view of 90 ° to cover the entire area 1 1 and the frame 2 .

One or more light sources 8 are arranged on the vehicle V to project into the zone 11 or part of zone 11 a pattern 82 the light source 8 has a wavelength observable by the camera 6. The camera 6 and the lighting means 8 are arranged relative to one another. to the other, so that the image of the pattern 82 of light marks provided by the camera 6 is different depending on the position of the opening 1. For example, the light beams 80 are oblique and / or asymmetrical with respect to the opening of the opening in zone 1 1. For example, the source 8 is laser. A link 9 between the computer 7 and the source or sources 8 allows the computer 7 to control the source or sources 8 for their ignition and extinction.

In the embodiment of Figure 1, the source 8 is provided on the fixed part 2, 3 of the vehicle. For example, the source 8 is provided in the lower corner of the frame 2 of the door and has an angle of emission of beams 80 over 90 ° to cover the entire area 11. The pattern 82 of light beams 80 is projected in the direction of the opening 1, for example on its edge 10, to be reflected along the beams 81 to the camera 6. For example, in this case, the light beams 80 projected by the source 8 are planar and limited in extent in their plane, being parallel to the same first direction of extension, for example horizontal, to form a series 82 of lines 80 visible on the opening, as is shown in Figure 3.

As explained below, the computer 7 controls the source 8 to turn on and off at a given frequency.

The spatial frequency of the projected lines of the pattern 82 can be modified and modulated to take into account the position of the camera 6, its spatial resolution and the shape of the opening 1.

In another embodiment not shown, the light source or sources 8 are arranged in the sidewall 10 of the opening 1, and / or also in the lower parts 21 and / or high 22 of the frame 2. In this case the light sources 8 may for example be formed by light-emitting diodes. In another embodiment not shown, the camera 6 can be provided on the opening 1, for example on the edge 10 delimiting the passage between the open opening and the opening 2.

In the embodiment of FIG. 1, the light beams 80 projected by the source 8 comprise a beam 80a emitted directly towards the camera 6, without reflection on the opening 1, and along the edge 20, in order to replace the anti-pinch joint traditionally used. The disappearance of this luminous point 80a in the image perceived by the camera 6 indicates the presence of a foreign body C near the amount. The pattern 82 of light marks 80 is therefore present in the image supplied by the camera 6 to the computer 7.

Beforehand, a learning step of the pattern 82 is carried out by the computer 7 in the absence of obstacles, by recording, for different intermediate positions of the opening 1 during its travel between the full open position and the closed position, images of the pattern

82 of light marks 80, taken by the camera 6. These images of the pattern 82 of light marks 80 are called reference images or patterns MREF of the camera 6 and are each recorded in association with the PREF reference position information of the camera. 1 opening for which the reference image was taken by the camera 6, in a base REF reference (memory) associated with the computer 7.

Subsequently, to detect the presence of a foreign body C during the use of the camera 6, the calculator 7 compares the light pattern 82 of the current image I of the camera 6 with the reference patterns MREF, in to determine whether this pattern 82 of the current image I corresponds to one of the reference patterns MREF. If so, it is estimated that the opening 1 is for this current image I in the reference position associated with the reference pattern MREF determined as corresponding to the pattern 82 observed and that no foreign body is detected. If it is not, it is determined that a foreign body C is in the path of opening 1. The computer determines the position of the foreign body by analyzing the differences between the reference MREF patterns and the pattern 82 observed.

An exemplary embodiment of the detection method implemented by the computer 7 is described below. In what follows: image (t) is called the current image I acquired by the camera 6 at the instant t, f is the frequency of acquisition of the images by the camera 6, the reason (t) is called the light signal 80 emitted by source 8 at time t and projected onto the image at time t, scene (t) is called the projection of gate 1 on the image at time t, called background (t ) the projection of the background on the image at time t.

We therefore have for a given image: pt + time _mt image degeneration (t) = (pattern (t) + scene (t) + background (t)).

In practice, it is chosen to illuminate by the source 8 the pattern at a frequency f less than the acquisition frequency f of the camera, for example equal to f = f / 4 or f '= f / 2. The lighting of source 8 is modeled by a function F ^* Rect ((2 ^* Pi / f) ^* 0.25 ^* t + offset), where t is in seconds, offset is a phase shift between 0 and π, and Rect (x ) is the step function equal to 1 for positive x and 0 for negative x. So we have :

, _r 22ππ_ image (t) = f (F (t) * Rect (1 + offset) + scene (t) + background (t)).

Jf-Δf Λ f

During a first step, for each new image acquired at time t, we calculate:

Diff (t) = image (t) -image (t-2Δt) that is to say:

dx

dx Dijf (t) =

L dscenëyX) d_fond (x),

F-Rect (- x + offset) - Rect (- (x-2At) + offset) dx dx

Then, during a second step, for each image I, the pixels are summed according to the direction of extension of the pattern 82 of emitted light marks, in order to obtain a signature S (t). In the previous example where this extension direction is horizontal, we sum the lines. For each line of the image, the sum of the gray level luminance values of each pixel of the line is calculated. Thus, a signature S (t), represented in FIGS. 4 and 5, is respectively constituted by S (t) at time t and S (t-Δt) at time t-Δt, where the abscissa represents the number of line of the image following the second direction, vertical, orthogonal to the first direction of extension, and where the ordinate the value of said sum on this line. Each peak of the signature S (t) therefore corresponds to a light marker 80.

During a third differentiation step, for each new image I, the effect of the background is eliminated by calculating the differential signature ΔS (t), equal to ΔS (t) = S (t) - S (t-Δt ) The effect of the background is reflected for example by variations due to shadows and reflections, encountered during the use of the vehicle, for example when the vehicle is under trees with the shadows of the leaves that move.

The differential signature ΔS (t) thus obtained contains mainly the light emitted by the light source 8 and reflected by the sliding side door 1, or any obstacle C located in the area 1 January.

During a fourth quantization step, the differential signature ΔS (t) is binarized to form a list of bits BΔS (t), a bit corresponding to a straight line in the direction of extension of the pattern 82, and therefore to a line in the example above as shown in Figure 6, where the abscissa represents the line number and the ordinate represents the corresponding value of the bit of BΔS (t). Of course, the differential signature ΔS (t) could also be quantized with more than one bit per line.

During a fifth step, the binarized signature BΔS (t) is compared with the binarized signatures of the reference patterns MREF in order to detect the presence of a foreign body C in the race of the opening 1. These binarized signatures of Reference MREF patterns are referred to as convenience reference MREF patterns in the following. If no reference pattern MREF of the reference base resembles the binarized signature BΔS (t), this implies the existence of a foreign body C in the race of the opening 1. Otherwise, the reference pattern MREF the closer to the binarized signature BΔS (t) allows to know the corresponding PREF position of the opening 1, as is shown for BΔS (t) in Figure 7 and for MREF in Figure 8, where the abscissa represents the line number and the ordinate represents the corresponding value of the bit of BΔS (t) and MREF. This fifth step is implemented for example in the following manner. For the current image I, and for each reference pattern MREF, the distance DIST between this current image I and the reference pattern MREF is calculated. If this distance DIST is less than a prescribed threshold distance TESTMIN, then no foreign body C is detected and the position of the opening 1 is estimated as being the position PREF associated with the reference pattern MREF for which the distance DIST is the weakest. The distance DIST is for example calculated by the absolute value of the sum on the bits of the differences between the binarized signature BΔS (t) and the reference pattern MREF, that is to say according to the following equation:

DIST = Σ (BΔS (t) * -MREFJ bit FIG. 9 represents in ordinate the DIST distance calculated for the various MREF patterns as abscissa represented by discrete points, while the DREF line represents the real distance.

If no reference pattern MREF matches or resembles the binarized signature BΔS (t), that is to say in the previous example if no reference pattern MREF checks the condition DIST <TESTMIN, it is possible to detecting the closest reference MREF pattern, ie the MREF pattern having the smallest distance DIST relative to the current image I. Then, from the missing lines and / or the additional lines of the current image I with respect to this pattern MREF, it is estimated the position of the foreign body C and the position of the opening 1.

The presence of a foreign body C is detected by the computer 7 by identifying the absence of illumination at the sidewall 10 of the door 1 and / or by identifying illumination areas that would not have existed if only the Door 1 was present.

When the means 4, 5 of control have been actuated, that the opening 1 closes towards the opening 2 and a foreign body has been detected, inhibition means cancel the closing command sent by the computer 7 to motor 4 to cause in real time at least the shutter stop (1).

In one embodiment, the camera and the light sources are not synchronized. The determined frequency of the pattern is not synchronized with the acquisition rate of the images. This avoids pulling a cable between the source of the pattern and the search means 7 of the pattern in the image. Moreover, a synchronization is not necessarily possible with the multiplex network of the vehicle and the calculation time in the computers of the network.

Claims

1. Device for detecting a foreign object on the stroke of a motorized opening of a motor vehicle, the opening being movable relative to a fixed portion (2, 3) of the vehicle between the one and the other a first position and a second position, characterized by at least one camera (6) monitoring at least a portion (1 1) of the area occupied by the opening (1) between its first and second position, means (8) lighting, able to produce a prescribed pattern (82) of light cues (80) observable in said portion (1 1) zone by the camera (6), the camera (6) being fit producing an image of the pattern (82) of light marks, means (7) for searching the pattern (82) of light marks (80) in at least one current image (I) of the camera (6), in order to determine , in the case where the pattern (82) of light marks (80) has not been found in the current image (I) of the camera (6), the presence of a foreign object on the race opening (1).

2. Detection device according to claim 1, characterized in that the search means (7) comprise means for comparing the image (I) of the camera (6) with a set of images (MREF) of reference. of the predetermined camera for predetermined positions (PREF) of reference of the opening (1) in its race, for determining said presence of the foreign body in the case where the current image (I) of the camera

(6) does not correspond to any reference image (MREF).

3. Detection device according to claim 2, characterized in that the search means (7) comprise means for estimating the position of the opening (1) for the current image (I) as being the position ( PREF) associated with the reference image (MREF) closest to the current image (I).

4. Detection device according to claim 3, characterized in that the search means (7) comprise means for estimating, in the case where the current image (I) of the camera (6) does not correspond to any image ( MREF), the position of the foreign body for the current image (I) by analyzing differences between the reference image (MREF) closest to the current image (I) and the current image (I) .

5. Detection device according to any one of the preceding claims, characterized in that the camera (6) and the means (8) for lighting are oriented in the direction (L) of the opening of the opening (1) between the first and second positions of the camera, the camera (6) and the lighting means (8) are arranged relative to one another so that the markers light (80) are in variable positions in the image of the camera (6) as a function of the position of the opening (1) in its race between one and the other of its first position and its second position. position.

6. Detection device according to any one of claims 1 to 5, characterized in that the camera (6) and the lighting means (8) are both located on the same element selected from the opening (1). ) and the fixed part (2, 3) of the vehicle and are arranged so that the pattern (82) of light marks (80) is projected at least in part by the lighting means (8) on the other one of the opening (1) and the fixed portion (2, 3) of the vehicle.

7. Detection device according to any one of claims 1 to 5, characterized in that the camera (6) is located on a member selected from the opening (1) and the fixed portion (2, 3) of the vehicle, the lighting means (8) are located on the other element of the opening (1) and the fixed part (2, 3) of the vehicle and comprise a plurality of localized light sources (8) each producing a light marker of the pattern (82).

8. A method for detecting a foreign body on the stroke of a motorized opening of a motor vehicle using the device according to any one of the preceding claims, the opening being movable by relative to another part (2, 3) of the vehicle between one and the other of a first position and a second position, characterized in that the pixels of at least one current image are summed ( I) from the camera

5 (6) in a first prescribed direction according to the prescribed pattern (82) of luminous landmarks (80) of the illumination means (8), so as to calculate a signature (S (t)) of the current image ( I) of the camera (6) in a second direction orthogonal to the first prescribed direction, the signature (S (t)) is quantized, 0 the quantized signature (S (t)) is compared to a set of signatures (MREF) reference values determined for a set of predetermined camera reference images for predetermined positions (PREF) of reference of the opening (1) in its stroke, for determining said presence of the foreign body in the case where the signature5 (S (t)) quantized does not correspond to any reference signature (MREF).

9. A method according to claim 8, characterized in that the quantization step is preceded by a step of differentiation of successive signatures (S (t), S (t-Δt)) to provide a differential signature (ΔS (t) ), the quantization step and the comparison step being performed on o said differential signature (ΔS (t)).

10. Motor vehicle, comprising a motorized opening (1) movable relative to a fixed portion (2, 3) of the vehicle between the first and second positions, means ( 4, 5, 7) for controlling the movement of the leaf (1) in the closing direction 5 between the first position and the second position, characterized in that it is provided with the device for detecting a foreign body on the stroke of the opening according to any one of claims 1 to 7, and means for stopping said closing movement of the opening (1) in the case where a foreign object is detected on the race of the opening by said device.