A motor vehicle telemetry lighting system comprising a light beam receiver module

Abstract

The invention relates to a telemetry system (1) of a motor vehicle comprising a receiving module (3) capable of receiving a light beam (F1), comprising: a plurality of elementary acquisition modules (32i,j) each comprising at least one photodetector (32a) capable of converting a light signal which it receives into an electrical signal, each acquisition module being capable of generating an elementary detection signal as a function of the electrical signal(s) converted by the photodetector(s) of the elementary acquisition module; an optical focusing device capable of receiving the light beam, said optical focusing device being arranged opposite the plurality of input faces of the elementary acquisition modules;a computing unit (4) capable of receiving elementary detection signals by the elementary acquisition modules (32i,j) and capable of detecting in each received elementary detection signal the presence of a predetermined data sequence; characterized in that the optical focusing device (33) has an optical axis (X), in that the elementary acquisition modules (32i,j) are arranged on either side of said optical axis (X) and in that at least a second elementary acquisition module (32i,j) further from the optical axis (X) than a first elementary acquisition module (32i,j) has dimensions greater than those of said first elementary acquisition module (32i,j) Figure to be published with the abbreviation: Fig. 1;

Description

Title of the invention: Light telemetry system for a motor vehicle comprising a module for receiving a light beam

[0001] The invention relates to the field of automotive lighting and / or light signaling, functions for detecting an object by a motor vehicle and estimating the distance separating this object from the vehicle. More specifically, the invention relates to a lighting and / or signaling system for a motor vehicle capable of implementing telemetry functions by means of the light that it emits.

[0002] It is known, in the automotive field, to use a pulsed light beam emitted by a light module of a lighting system of a motor vehicle to perform a given photometric function.

[0003] Conventionally, the light source enabling the emission of this light beam is controlled by a pulse width modulated electrical signal, or PWM (from the English "Pulse Width Modulation"). The light source is thus periodically activated and deactivated by this PWM signal, so that the emitted light beam is composed of light pulses succeeding one another with a frequency high enough that the human eye can no longer distinguish them. The intensity of the emitted light beam is a function of the duty cycle of this PWM signal, so that it is possible to control it by adjusting this duty cycle and therefore to perform a photometric function.

[0004] Beyond the realization of one or more photometric functions, such as a daytime running light or dipped-beam lighting, various functions can be implemented by this type of light module. For example, the light source of the light module can be controlled so that the pulses of the emitted light beam carry a data sequence. The lighting system can thus be equipped with a reception module in order to receive the emitted light beam, after reflection on an object in the vicinity of the vehicle. A computing unit of the motor vehicle can then, after detecting the data sequence in the received light beam, determine the time of flight of the emitted light beam and therefore evaluate the distance separating the vehicle from the object.

[0005] In this way, the light beam can retain its original function, namely performing a photometric function, while allowing the lighting system to implement a telemetry function, which can be particularly advantageous, for example, for driving assistance functions or in the context of a autonomous or semi-autonomous driving.

[0006] However, this type of system based on the use of a transmission module capable of both performing a photometric light function and data transmission has drawbacks. Indeed, the reception module intended to receive the light beam carrying the data, whether it is arranged in the same vehicle or in another vehicle, must comprise at least one photodetector to convert this light beam into an electrical signal in order to demodulate this signal and extract a data sequence therefrom.

[0007] However, under certain conditions, this photodetector may see its signal-to-noise ratio significantly degraded, taking into account the sources of stray light present in the environment of the vehicle, such as urban lighting, automobile lighting of passing or following vehicles, or even sunlight, and the nature of the objects present in the environment, and in particular their reflective capacity. This degradation of the signal-to-noise ratio may then reduce the accuracy of the calculation unit in estimating the distance of the target object, or even lead to false positive detections.

[0008] Furthermore, the detection of objects must be as good as possible, regardless of the position of said objects, in the field of view of the photodetector(s). However, on the lateral ends of the field of view the detection of an object in said field is more likely to be affected by a field curvature aberration introduced by the optical unit of the receiving module. Therefore, an object located on the lateral ends of the field of view of the photodetector(s) cannot be correctly focused by the sensors. In order to maintain the same angular resolution, an additional field flattening lens will improve the sharpness of the edges. However, this is an additional cost for a low-cost product.

[0009] There is thus a need for a lighting system for a motor vehicle, capable of performing both a given regulatory photometric function and a telemetry function, which is effective in all positions of the object to be detected, in particular on the lateral edges of the detection field of the sensors.

[0010] The present invention is placed in this context, and aims to meet this need.

[0011] To these ends, a lighting system for a motor vehicle has been developed, comprising: a reception module capable of receiving a light beam, comprising: a plurality of elementary acquisition modules each comprising at least one photodetector capable of converting a light signal that it receives into an electrical signal, each acquisition module being capable of generating an elementary detection signal as a function of the electrical signal(s) converted by the photodetector(s) of the elementary acquisition module, an optical focusing device capable of receiving the light beams, said optical focusing device being arranged facing the plurality of input faces of the elementary acquisition modules; and a calculation unit capable of receiving the elementary detection signals generated by the elementary acquisition modules and capable of detecting in each elementary detection signal received the presence of a sequence of predetermined data.

[0012] According to the invention, the optical focusing device has an optical axis, the elementary acquisition modules are arranged on either side of said optical axis, and at least one second elementary acquisition module further from the optical axis than a first elementary acquisition module has dimensions greater than those of said first elementary acquisition module.

[0013] The invention thus proposes to compensate for the curvature aberrations introduced by the optical device by enlarging the dimension of the elementary acquisition modules, from the center of the reception module towards its edges, which makes it possible to avoid the use of a field flattening lens, or a curved sensor. The dimension of the elementary acquisition modules can thus be adapted according to the field curvature function of the optical focusing device, at the cost of a loss of angular resolution on the edges of the field of vision of the reception module. This loss is however acceptable to the extent that a high angular resolution is necessary in the axis of the vehicle, and not on the edges of the road.

[0014] Advantageously, the plurality of elementary acquisition modules is arranged in a matrix, the elementary acquisition modules being for example mounted on the same flat support. For example, all of the photodetectors can form a sensor, for example a single electronic component. For example, each photodetector, or each plurality of photodetectors, may have a width and / or a length of less than about ten micrometers, which makes it possible to obtain a reception field of the elementary acquisition module of at most 0.1° and therefore to increase the spatial resolution of the reception module.

[0015] The elementary acquisition modules may advantageously be distributed on either side of the optical axis of the optical focusing device, symmetrically or not.

[0016] The sensor comprises acquisition modules arranged according to a matrix arrangement formed by rows and columns of acquisition modules. It is thus understood that the sensor may have an arrangement of its elementary acquisition modules according to a symmetry of revolution relative to the center of the sensor corresponding to the place where the optical axis of the focusing optics passes.

[0017] Advantageously, the or each photodetector of each elementary acquisition module is an avalanche photodiode. This type of photodetector is also known as SPAD, from the English “Single-Photon Avalanche Diode”. The set of avalanche photodiodes can thus form a photomultiplier on silicon or SiPM (from the English "Silicon PhotoMultiplier"). This type of photodetector can detect the incidence of a single photon with a high gain, for example of the order of 106, and therefore compensate for the degradation of the signal-to-noise ratio due to external conditions

[0018] Advantageously, each elementary acquisition module comprises a demodulation unit connected to the or each photodetector and arranged to extract a data sequence, called demodulated, from an electrical signal converted by this photodetector, said demodulated data sequence forming said elementary detection signal.

[0019] In a particular embodiment, each demodulation unit comprises a comparator arranged to compare the electrical signal converted by each photodetector with a given threshold value and to generate said elementary detection signal as a function of said comparison.

[0020] Preferably, each elementary acquisition module comprises a plurality of photodetectors, the comparator being arranged to compare the electrical signal converted by each photodetector to a given threshold value and to generate an elementary detection sub-signal as a function of said comparison. Where appropriate, the comparator is arranged to sum the elementary detection sub-signals to form the elementary detection signal.

[0021] In a particular embodiment, for each elementary detection signal that it receives, the calculation unit is arranged to estimate values ​​of a correlation function between said elementary detection signal and said sequence of predetermined data and to detect the presence of said sequence of predetermined data in said elementary detection signal from said values ​​of the correlation function.

[0022] For example, the calculation unit is arranged to estimate each value of the correlation function between said elementary detection signal and said predetermined data sequence by evaluating the cross-correlation of the elementary detection signal and said predetermined data sequence delayed by a given duration associated with said value.

[0023] In other words, each value of the correlation function is thus associated with a value of a time shift of the modulating sequence used to estimate this value of the correlation function. The calculation unit is thus arranged to identify the time shift value associated with the maximum value of the cross-correlation function.

[0024] Preferably, the calculation unit is arranged to determine the value of a peak of said correlation function, to compare said peak value with a predetermined threshold value and to detect the presence of said predetermined data sequence. terminated in said elementary detection signal as a function of said comparison.

[0025] Thus, the invention makes it possible to improve the signal-to-noise ratio, in particular by increasing the dimensions of the elementary acquisition modules since an elementary acquisition module having larger dimensions makes it possible to receive a greater quantity of light and consequently, better detection as a function of the noise.

[0026] In a particular embodiment, the dimensions of the input face of the second elementary acquisition module are greater than the dimensions of the input face of the first elementary acquisition module. For example, it may be provided that the number of photodetectors included in an elementary acquisition module is identical for all the acquisition modules, and that the dimensions of these photodetectors vary from one module to another, these dimensions increasing from the center of the reception module, defined by the optical axis of the optical focusing device, towards the edges of the reception module.

[0027] Preferably, the dimensions of the input face of each elementary acquisition module increase with the distance of said elementary acquisition module from the optical axis of the optical focusing device. In this embodiment, the width of the elementary acquisition modules can thus increase, continuously and linearly or non-linearly, from the center of the reception module towards its edges.

[0028] In another particular embodiment, the plurality of elementary acquisition modules comprises a first and a second group of elementary acquisition modules, the first elementary acquisition module belonging to the first group of elementary acquisition modules, the second elementary acquisition module belonging to the second group of elementary acquisition modules, and the dimensions of the input face of each elementary acquisition module of the second group are greater than or equal to the dimensions of the input face of each elementary acquisition module of the first group, the dimensions of the input face of each elementary acquisition module of the first group are constant and the dimensions of the input face of each elementary acquisition module of the second group increase with the distance of said elementary acquisition module from the optical axis of the focusing device.

[0029] Thus, it is understood that the elementary acquisition modules of the first group have the same dimensions and the elementary acquisition modules of the second group have dimensions which increase as one moves away from the optical axis.

[0030] The increase in the dimensions of the elementary acquisition modules or their input faces may be an increasing increase as the modules elementary acquisitions move away from the optical axis of the focusing device or even a step increase.

[0031] Thus, in another embodiment, the plurality of elementary acquisition modules comprises a first and a second group of elementary acquisition modules, the first elementary acquisition module belonging to the first group of elementary acquisition modules, the second elementary acquisition module belonging to the second group of elementary acquisition modules, the dimensions of the input face of each elementary acquisition module of the second group are greater than the dimensions of the input face of each elementary acquisition module of the first group, and the dimensions of the input face of each elementary acquisition module of the first group and of the second group are constant.

[0032] Preferably, the first and second groups of elementary acquisition modules are coplanar, more preferably the first and second groups form a line.

[0033] Preferably, the plurality of elementary acquisition modules comprises a third group of elementary acquisition modules arranged so that the second group is juxtaposed with the first group on one side of the optical axis of the optical focusing device and the third group is juxtaposed with the first group on the other side of the optical axis of the optical focusing device.

[0034] In a particular embodiment, the dimensions of the elementary acquisition modules of the second and third groups are similar.

[0035] In a particular embodiment, the optical axis of the focusing device represents an axis of symmetry and is arranged to pass through the center of the first group of elementary acquisition modules.

[0036] In yet another particular embodiment, the number of photodetectors of the second elementary acquisition module is greater than or equal to the number of photodetectors of the first elementary acquisition module. In this embodiment, the dimensions of an elementary acquisition module thus depend on the number of photodetectors included in this elementary acquisition module.

[0037] Preferably, the dimensions of the photodetectors are identical for all the elementary acquisition modules.

[0038] In yet another particular embodiment, the pitch separating at least two adjacent photodetectors of the second elementary acquisition module is greater than or equal to the pitch separating at least two adjacent photodetectors of the first elementary acquisition module. In this embodiment, the dimensions of an elementary acquisition module thus depend on the space separating two neighboring photodetectors of the same elementary acquisition module.

[0039] In one embodiment of the invention, the telemetry system comprises a transmission module comprising a light module capable of emitting a light beam, and a modulation unit capable of receiving a data sequence, called a modulating sequence, and arranged to modulate the light beam emitted from said modulating sequence. Said modulating sequence thus forms said predetermined data sequence that the calculation unit seeks to detect.

[0040] The light beam may for example be a pulsed beam, each pulse corresponding to one or more consecutive high values ​​of the modulating data sequence and the interval separating two consecutive pulses corresponding to one or more consecutive low values ​​of this modulating data sequence. Each pulse of the modulated light beam is emitted with a peak light power, so that the average light power of the emitted modulated light beam is thus defined by the peak light power and the duty cycle of the modulating data sequence.

[0041] The light beam received by the receiving module thus contains the reflection of the light beam by an object to be detected. Said elementary detection signal received by the calculation unit is therefore formed from a data sequence, called demodulated, composed of the delayed modulating sequence and noise. Each value of the correlation function estimated by the calculation unit is associated with a value of a time shift of the modulating sequence, or of the demodulated sequence, used to estimate this value of the correlation function. The correlation function between this demodulated data sequence and the modulating sequence is therefore a function of the autocorrelation of this modulating sequence.

[0042] It is thus possible to detect the presence of this modulating data sequence in the received light beam, after reflection on an object in the environment of the vehicle and thus detect the presence of this object as well as estimate its distance from the vehicle.

[0043] In one embodiment of the invention, the light module is capable of emitting a light beam whose spectrum has a peak at a wavelength in the visible range, in particular between 400 nm and 500 nm. Advantageously, the light module comprises a light source comprising a semiconductor generator capable of emitting an elementary light beam, in particular whose spectrum has a peak at a wavelength in the visible range, and a photoluminescent element capable of converting said elementary light beam to obtain said light beam.

[0044] The semiconductor may for example be a gallium nitride, or GaN, capable of emitting, by electroluminescence and in response to an electric current passing through it, rays of blue light. The photoluminescent element may for example be in the form of a resin comprising a yttrium garnet and cerium-doped aluminum, or CE:YAG, capable of absorbing blue light and, by photoluminescence and in response to the excitation produced by this light, of emitting rays of yellow light. The photoluminescent element is arranged on the generator so that a part of the blue light rays excites this element so that it emits, by photoluminescence, rays of yellow light. The other part of the blue light rays passes through this element. Thus, the light source simultaneously emits, when electrically powered, rays of blue and yellow light, the light thus formed appearing white to the human eye.

[0045] The light source may thus be a laser type source, a light-emitting diode, a vertical cavity surface-emitting laser diode, also called VCSEL (from the English “Vertical-Cavity Surface-Emitting Laser”) or even a superluminescent diode or SLED (from the English “Superluminescent diode”).

[0046] Advantageously, the light module may comprise an optical unit arranged to project the light rays emitted by the light source to form said light beam.

[0047] Advantageously, the modulation unit is arranged to generate a pulse width modulated control signal, to modulate said control signal from the modulating data sequence and to control the emission of said light beam by the light module from the modulated control signal. For example, the modulation unit may be arranged to convert the modulating data sequence into a modulating signal and to modulate, for example in amplitude, frequency or phase, the control signal with this modulating signal.

[0048] Where appropriate, the modulation unit may be arranged to control the light source of the light module, and in particular an electrical power supply supplied to this light source, to modulate the light beam.

[0049] Advantageously, the calculation unit is arranged to generate a modulating data sequence, in particular of the pseudo-random binary type, to transmit the modulating data sequence to the modulation unit of the transmission module for the transmission of a light beam modulated by the transmission module.

[0050] A pseudo-random binary sequence, or PRBS (from the English "PseudoRandom Binary Sequence"), is a data sequence composed of high values, namely "1s", and low values, namely "0s". This type of sequence has particularly interesting properties. Indeed, its autocorrelation function is maximum for a zero time shift, that is to say when the sequence is compared to itself, and has a value significantly lower than this maximum for all other time shifts, that is to say when the sequence is compared to time-shifted versions of itself.

[0051] Furthermore, the cross-correlation function between two pseudo binary sequences random sequences is significantly lower than the maximum of the autocorrelation functions of these sequences. Finally, this type of sequence is generally generated using a linear feedback shift register, or LFSR, which produces a periodic recurring sequence whose pattern is a pseudo-random binary sequence.

[0052] Taking into account the autocorrelation properties of pseudorandom binary sequences, the correlation function thus estimated will be maximum for the time shift value corresponding to the time of flight of the modulated light beam emitted, reflected then received, even in the event of significant noise.

[0053] Consequently, the calculation unit can identify this time shift value associated with the maximum value of the correlation function with significant precision and deduce therefrom the distance separating the object on which the beam was reflected and the motor vehicle.

[0054] Furthermore, taking into account the cross-correlation properties, it thus appears unlikely that the reception of a modulated light beam emitted by an equivalent system of another motor vehicle would lead to the detection of a false positive.

[0055] Finally, it is understood that the detection is carried out not on a single pulse but on a complete data sequence, so that the signal-to-noise ratio of the system is improved.

[0056] Advantageously, the emission module is arranged so that the light beam participates, totally or partially, in the realization of a predetermined regulatory photometric function. It could for example be a daytime running light or DRL (from the English "Daytime Running Lamp"), which has the advantage of being emitted in a wide field with a low intensity.

[0057] Advantageously, the transmission module is arranged in a front headlight of the motor vehicle. Preferably, the reception module and the transmission module are arranged in the same front headlight of the vehicle.

[0058] Of course, the various features, variants and embodiments of the invention may be combined with each other in various combinations to the extent that they are not incompatible or mutually exclusive.

[0059] Furthermore, various other characteristics of the invention emerge from the appended description given with reference to the drawings which illustrate non-limiting forms of embodiment of the invention and where:

[0060] [Fig.l] represents, schematically and partially, a view of a telemetry system of a motor vehicle according to an exemplary embodiment of the invention.

[0061] [Fig.2] schematically represents an example of operation of the system in the absence of detection of the predetermined data sequence.

[0062] [Fig.3] represents, schematically and partially, an example of operation of the system of [Fig.l] when implementing a telemetry method.

[0063] [Fig.4] represents, schematically and partially, a particular embodiment of the arrangement of the elementary acquisition modules of the telemetry system according to the invention.

[0064] [Fig.5] represents, schematically and partially, another particular embodiment of the arrangement of the elementary acquisition modules of the telemetry system according to the invention.

[0065] [Fig.6] represents, schematically and partially, a third particular embodiment of the arrangement of the elementary acquisition modules of the telemetry system according to the invention.

[0066] [Fig.7] represents, schematically and partially, a fourth particular embodiment of the arrangement of the elementary acquisition modules of the telemetry system according to the invention.

[0067] It should be noted that in these figures the structural and / or functional elements common to the different variants may have the same references.

[0068] Of course, various other modifications may be made to the invention within the scope of the appended claims.

[0069] [Fig.l] illustrates a telemetry system 1 of a vehicle comprising a transmission module 2, a reception module 3, and a calculation unit 4.

[0070] The emission module 2 comprises a light module 21 capable of emitting a first light beam Fl, and a modulation unit 22 capable of receiving a modulating data sequence Seq and arranged to modulate the light beam Fl emitted from said modulating sequence Seq.

[0071] The first emission module 2 is for example arranged in a headlight of the motor vehicle.

[0072] The light module 21 is arranged so that the light beam Fl that it emits has an electromagnetic spectrum of which at least a portion is located in the visible spectrum. Preferably, the spectrum of this light beam Fl has an intensity peak, or line, in the blue at 450 nm. It will be noted that it is possible for the spectrum to have other intensity peaks, in the visible and / or in the infrared.

[0073] To the extent that the light beam Fl is composed, partially or totally, of white light, it is possible to use this light beam to participate, partially or totally, in the realization of a predetermined photometric function, in particular regulatory. In this case, the light module 21 may comprise an optical unit arranged to shape this light beam Fl so that its photometric distribution satisfies the requirements of said function. It may, for example, be provided that the light beam Fl participates in the realization of a function of the daytime running light, or DRL, type.

[0074] In addition to this photometric function, the light beam Fl allows the system 1 to perform functions of detecting and evaluating the position of an obstacle on the road and / or communicating with another vehicle or with a road infrastructure.

[0075] For these purposes, the modulation unit 22 is arranged to modulate the light beam Fl emitted by the light module 21, from the sequence of modulating data Seq that it receives, for example by controlling the electrical power supplied to the light source of the light module.

[0076] It will thus be possible to provide that the modulation unit 22 comprises a generator of a pulse-width modulated control signal. This control signal makes it possible to control a switching power supply (not shown) of the light source of the light module 21. Conventionally, the duty cycle of this control signal, set by the modulation unit 22, thus makes it possible to control the average electrical power supplied to the light source, and therefore to control the light intensity of the light beam F1, so as to satisfy the requirements of the photometric function that it performs.

[0077] In the example described, the modulation unit 22 is arranged to convert the data sequence Seq into a modulating signal and to modulate the initial control signal using this modulating signal. It will be noted that several types of modulation can be used indifferently within the framework of the present invention, and in particular an all-or-nothing modulation (OOK for "On Off Keying"), a pulse code modulation (PCM for "Puise Code Modulation"), a pulse amplitude modulation (PAM for "Puise Amplitude Modulation"), a pulse width modulation (PWM for "Puise Width Modulation") or a pulse position modulation (PPM for "Puise Position Modulation").

[0078] The light beam Fl thus emitted is composed of a train of light pulses succeeding one another with a sufficiently high frequency, for example greater than 30 MHz, in particular between 50 MHz and 100 MHz, so that the human eye can no longer distinguish them. Furthermore, the amplitude, the width and / or the position of each pulse with respect to the period allows the light beam Fl to transport the data sequence Seq.

[0079] If an object is present in the environment of the motor vehicle, it can reflect this light beam F1 towards the reception module 3, which thus receives a light beam F2.

[0080] In connection with [Fig.2] representing an exemplary embodiment of a reception module 3, this reception module 3 comprises a plurality of elementary acquisition modules 32ij, each comprising several photodetectors 32a capable of converting a light signal that it receives into an electrical signal. Each elementary acquisition module 32ij further comprises a demodulation unit 34, comprising a comparator arranged to compare the electrical signal converted by each photodetector 32a of the module 3¾ to the same given threshold value. The demodulation unit 34 is thus arranged to generate, from each of the comparisons of the electrical signals from the photodetectors 32a, an elementary detection sub-signal, and to sum the elementary detection sub-signals thus generated to generate an elementary detection signal Sdcr which therefore forms a data sequence, called demodulated.

[0081] The photodetectors 32a are identical and are each formed by an avalanche photodiode of a silicon photomultiplier. It will be noted that the dimensions of the photodetectors are of the order of a micrometer. The assembly thus forms a sensor whose spatial reception resolution is of the order of 1°, or even 0.1°, and whose detection capabilities, due to the use of avalanche photodiodes, are particularly high, even in the case of degraded acquisition conditions.

[0082] Each of the photodetectors 32a of the same elementary acquisition module 32ij can thus convert the portion of the light beam F2 that it receives into an electrical signal that it transmits to the demodulation unit 34, which can then extract a data sequence Sde^ from it to transmit it to the calculation unit 4.

[0083] The elementary acquisition modules 32ij are arranged in a matrix manner, on N lines and M columns and are mounted on the same flat support opposite which an optical focusing device 33 is provided, which may for example comprise a stack of different lenses.

[0084] In the example described, the reception module 3 is arranged in the headlight of the motor vehicle, next to the transmission module 2.

[0085] The calculation unit 4 is capable of receiving the elementary detection signals Sdc, generated by the elementary acquisition modules 3¾ and capable of detecting in each elementary detection signal Sdc, received, the presence of the modulating data sequence Seq.

[0086] For these purposes, the calculation unit 4 is thus arranged to estimate values ​​of a correlation function Fcorr between each received elementary detection signal Sdc, , and said modulating data sequence Seq, and to detect in this elementary detection signal Sdcir the presence of the modulating data sequence Seq from these values ​​of the correlation function Fcorr. In the event of detection, it can then determine a time of flight r separating the emission of said first emitted modulated light beam F1 from the reception of said received light beam F2.

[0087] The calculation unit 4 can thus carry out functions of detecting and evaluating the position of an object on the road, as will be described in connection with [Fig.2] which presents a telemetry method implemented by the light system 1.

[0088] In a first step E1, the calculation unit 4 generates, periodically, a modulating data sequence Seq, for example of binary type, composed of “0” and “1”, pseudo random and of maximum size, also called M-sequence, having a duty cycle of 50%.

[0089] The calculation unit 4 transmits the sequence of modulating data Seq to the modulation unit 22 of the transmission module 2 for the simultaneous transmission of the light beam Fl by the transmission module 2.

[0090] In a second step E2, the modulation unit 22 modulates the light beams Fl emitted by the light module 21 from this data sequence Seq. Thus, each modulation unit 22 converts the data sequence Seq into a modulating signal and modulates the initial control signal using this modulating signal.

[0091] It will be noted that in the example described, each light pulse of the light beam F1 emitted by the light module 21 corresponds to a bit of value “1” of the modulating sequence Seq. The average power of a portion of the light beam F1 containing the sequence Seq is thus defined by the number of bits of value “1” of this sequence Seq with respect to the total number of bits of this sequence, by the duration of the pulses and by the peak power of these pulses.

[0092] The light beam Fl is thus emitted until it reaches an object O, located in the environment of the vehicle, which reflects it in the direction of the reception module 3.

[0093] Depending on the angular position of the object O, the light beam F2 received by the reception module 3 is thus concentrated on one of the elementary acquisition modules 3¾.

[0094] When the sunlight conditions in the vicinity of the vehicle are particularly significant, sunlight is thus added to the light beam F2 received by the reception module 3. The light beam F2 received by the reception module 3 is thus composed of a part of the light beam Fl reflected by the object O and of noise, for example generated by sources of stray light such as urban lighting, automobile lighting, or even the sun.

[0095] In a third step E3, each of the elementary acquisition modules 3¾ thus extracts, using its demodulation unit 34, an elementary detection signal Sdeij which it transmits to the calculation unit 4.

[0096] For each elementary detection signal Sde^ that it receives, the calculation unit 4 estimates, in a fourth step E4, values ​​of a correlation function Fcorr between the modulating sequence Seq and this elementary detection signal Sde^.

[0097] The calculation unit 4 thus evaluates, for a plurality of time shift values, the value of the cross-correlation, by means of a cyclic convolution product, between each elementary detection signal Sde^ and the modulating sequence Seq delayed according to each of the time shift values.

[0098] Taking into account the autocorrelation and cross-correlation properties of the modulating sequence, the correlation function Fcorr will thus be maximum for a time shift value corresponding to the time of flight of the light beam Fl, separating the instant when it is emitted by the emission module 2 and the instant when it is received by an elementary acquisition module 3¾ of the reception module 3, the modulating sequence Seq delayed by this value thus corresponding substantially to the elementary detection signal Sdcir to within the noise.

[0099] In a fifth step E5, the calculation unit 4 identifies the maximum value Fcorr_max of each correlation function Fcorr associated with each elementary acquisition module 3¾ and compares it to a threshold value Vs.

[0100] In the case where the maximum value of a correlation function Fcorr is greater than the threshold value Vs, the modulating sequence Seq is considered to be detected by the calculation unit 4 in the elementary detection signal Sdc, , coming from the elementary acquisition module 32ij associated with this correlation function Fcorr. An object O is therefore detected in the angular range, or the pixel, monitored by this elementary acquisition module 32ij and the calculation unit 4 can then estimate, in a sixth step E6, the value r of the flight time of the light beam Fl between the object O and the vehicle, associated with this maximum value, as well as the distance d separating the object O from the vehicle.

[0101] In connection with [Fig.3], we will describe an example of embodiment of the reception module 3.

[0102] As explained in connection with [Fig.l], the elementary acquisition modules 3¾ are arranged on the same flat support 35.

[0103] The optical focusing device 33 has an optical axis X and a substantially curved focal surface F, taking into account the field curvature of the lenses making up the optical focusing device 33. In the example illustrated, the optical axis X of the optical focusing device 33 forms the optical axis of the reception module 3.

[0104] The elementary acquisition modules 3¾ are distributed symmetrically on either side of the optical axis X, the central elementary acquisition module being positioned as close as possible to the focal surface F.

[0105] As illustrated in [Fig.3], when the light beam F2 comprises light rays RI originating from the reflection of the beam Fl on an object O substantially centered on the optical axis X of the reception module 3, these light rays arrive substantially parallel to this optical axis X on the optical focusing device 33. They are thus focused on an area whose dimensions correspond substantially to those of the central elementary acquisition module.

[0106] Conversely, when the light beam F2 comprises light rays R2 coming from the reflection of the beam F1 on an object O substantially offset with respect to the optical axis X of the receiving module 3, these light rays arrive substantially parallel to a direction oblique to this optical axis X on the optical focusing device 33. These parallel rays which arrive inclined with respect to the optical axis X are focused at the level of the focal surface F of the optical focusing device 33, in the field. However, the focusing surface F is curved due to the aberrations of the optical focusing device 33. Because the support 35 on which the elementary acquisition modules 32^ are arranged is flat, the elementary acquisition modules 32^ are arranged further and further behind the focal surface F as one moves away from the optical axis X.Thus, the more the rays arrive inclined relative to the optical axis O, the more they will illuminate a large area at the level of the flat support 35 in which the elementary acquisition modules 3¾ are arranged.

[0107] In order to compensate for these aberrations and so as to avoid having to bend the support 35 or the elementary acquisition modules 32ij, the dimensions Lij of each elementary acquisition module 32;,j increase with the distance of said elementary acquisition module 3¾ from the optical axis X of the optical focusing device 33.

[0108] It is thus possible to define a first elementary acquisition module and a second elementary acquisition module further from the optical axis X of the reception module 3 than the first elementary acquisition module, the second elementary acquisition module having dimensions greater than those of the first elementary acquisition module.

[0109] In the example of [Fig. 3], each elementary acquisition module 32;,j comprises the same number of photodetectors 32a, in this case a single photodetector 32a. However, the dimensions of the receiving face of the photodetector 32a of each elementary acquisition module 32;,j, and therefore those of the input face of this elementary acquisition module 32;j, increase with the distance of said elementary acquisition module 32;j from the optical axis X of the optical focusing device 33. In this case, the dimensions of the input face of the second elementary acquisition module are greater than those of the input face of the first elementary acquisition module. In the example of [Fig. 3], the increase in the dimensions of the input faces of the elementary acquisition modules 32;j is continuous.In other words, each elementary acquisition module 32i+1j adjacent to another elementary acquisition module 32;,j and further from the optical axis X than this other module 32;j has an input face whose dimensions are greater than those of this other module 3¾. .

[0110] Another example of the embodiment of the reception module 3 is shown in [Fig.4].

[0111] In this example, the dimensions of the photodetectors 32a are identical for all the elementary acquisition modules 3¾. On the other hand, the number of photodetectors 32a of each elementary acquisition module 3¾ increases with the distance of said elementary acquisition module 3¾ from the optical axis X of the optical focusing device 33. In this case, the number of photodetectors of the second elementary acquisition module is greater than the number of photodetectors of the first elementary acquisition module. Similarly to [Fig. 3], in the example of [Fig. 4], the increase in the dimensions of the input faces of the elementary acquisition modules 3¾ is continuous.

[0112] Another example of the embodiment of the reception module 3 is shown in [Fig.5].

[0113] In this example, the dimensions and number of photodetectors 32a are identical for all the elementary acquisition modules 3¾. On the other hand, the pitch p separating two adjacent photodetectors 32a of each elementary acquisition module 32ij increases with the distance of said elementary acquisition module 32ij from the optical axis X of the optical focusing device 33. In this case, the pitch separating at least two adjacent photodetectors of the second elementary acquisition module is greater than the pitch separating at least two adjacent photodetectors of the first elementary acquisition module. Similarly to [Fig.3], in the example of [Fig.5], the increase in the dimensions of the input faces of the elementary acquisition modules 32ij is continuous.

[0114] Another example of the embodiment of the reception module 3 is shown in [Fig.6].

[0115] In this example, the plurality of elementary acquisition modules 3¾ is distributed into a first group 321, a second group 322 and a third group 323 of elementary acquisition modules 32ijj>arranged so that the second group 322 is juxtaposed with the first group 321 on one side of an optical axis X of the optical focusing device 33 and the third group 323 is juxtaposed with the first group 321 on the other side of the optical axis X of the optical focusing device 33.

[0116] In this example, the dimensions of the input face of each elementary acquisition module 3¾ of the first group 321 are constant. The dimensions of the input face of each elementary acquisition module 3¾ of the second group 322 increase with the distance of said elementary acquisition module 3¾ from the optical axis X of the focusing device 33. Symmetrically, the dimensions of the input face of each elementary acquisition module 3¾ of the third group 323 also increase with the distance of said elementary acquisition module 32ij from the optical axis X of the focusing device 33.

[0117] In the example of [Fig.6], the dimensions of the photodetectors 32a are identical for all the elementary acquisition modules 3¾. In order to vary the di dimensions of the input faces of the elementary acquisition modules 32;,j of the second and third groups 322, 323, it was chosen to vary the number of photodetectors 32a of each successive elementary acquisition module 32;,j of these second and third groups 322, 323, as in the embodiment of [Fig.4]. Thus, the number of photodetectors 32a of each elementary acquisition module 32ij of these second and third groups 322, 323 increases with the distance of said elementary acquisition module 32;,j from the optical axis X of the optical focusing device 33. It may be envisaged, alternatively or cumulatively, to use the same number of photodetectors, or even a single photodetector, for all the elementary acquisition modules of the first, second and third groups, and to vary the dimensions of the receiving face of these photodetectors, as in the embodiment of [Fig.3], or to vary the pitch separating two adjacent photodetectors of an elementary acquisition module, as in the embodiment of [Fig.5], or any other appropriate method.

[0118] Another example of the embodiment of the reception module 3 is shown in [Fig.7].

[0119] In this example, the plurality of elementary acquisition modules 32;,j is distributed into a first group 321, a second group 322 and a third group 323 of elementary acquisition modules 3 2;,j arranged so that the second group 322 is juxtaposed with the first group 321 on one side of an optical axis X of the optical focusing device 33 and the third group 323 is juxtaposed with the first group 321 on the other side of the optical axis X of the optical focusing device 33.

[0120] In this example, the dimensions of the input face of each elementary acquisition module 3¾ of the first group 321 are constant. The dimensions of the input face of each elementary acquisition module 3¾ of the second group 322 are also constant, while being greater than the dimensions of the input face of each elementary acquisition module 32;,j of the first group 321. Symmetrically, the dimensions of the input face of each elementary acquisition module 3¾ of the third group 323 are also constant, while being greater than the dimensions of the input face of each elementary acquisition module 3¾ of the first group 321. This is thus an increase in the dimensions of the input faces of the elementary acquisition modules 32;,j by step.

[0121] In a similar manner to the embodiment of [Fig.6], the methods of the embodiments of [Fig.3] to [Fig.5] can be used indifferently to vary the dimensions of the input face of the elementary acquisition modules 32;j of said first, second and third groups.

[0122] It will also be possible to envisage adding other groups of elementary acquisition modules 32jj whose input faces have constant dimensions and are larger than those of the previous groups, for example by combining the modes of realization of [Fig.6] and [Fig.7] between them. The number of elementary acquisition modules 32ij for each of said groups may be one or more, and may be different for each of the groups.

[0123] The foregoing description clearly explains how the invention makes it possible to achieve the objectives it has set itself, namely to provide a lighting system for a motor vehicle, capable of performing both a given regulatory photometric function and a telemetry function, and which is effective in all positions of the object to be detected, in particular on the lateral edges of the detection field of the sensors, without increasing the cost or complexity of the receiving module. These objectives are notably achieved by increasing the dimensions of the elementary acquisition modules of the receiving module with the distance from the optical axis X of the optical device of the receiving module, in order to compensate for the field aberrations introduced by this optical device.

[0124] Thus, it is understood that these embodiments are not mutually exclusive and that the invention also relates to a possible combination of the latter. For example, still within the scope of the invention, it is possible for the dimensions of the input face of the photodetectors 32a of each elementary acquisition module 32ij to increase and for the spacing between said photodetectors 32a to also increase as the latter move away from the optical axis X of the optical focusing device 33.

[0125] In the same way, it is of course understood within the scope of the invention that the dimensions of the input face of each photodetector 32a of each elementary acquisition module 3¾ can increase and that the number of photodetectors 32a of each elementary acquisition module 3¾ can also increase with the distance of said elementary acquisition module 3¾ from the optical axis X of the optical focusing device 33.

[0126] In any event, the invention cannot be limited to the embodiments specifically described in this document, and extends in particular to any equivalent means and to any technically effective combination of these means. In particular, other configurations of the emission modules may be provided, and in particular an emission module using other types of light source than those described, such as a laser diode, a VCSEL or a SLED or an RGB diode. It may also be possible to provide other photometric functions than that described, and in particular lighting functions of the dipped beam type or signaling functions of the position light or direction indicator type.

Claims

1.

2.

3. Claims Telemetry system (1) of a motor vehicle comprising: - a reception module (3) capable of receiving a light beam (F2), comprising: • a plurality of elementary acquisition modules (32ij) each comprising at least one photodetector (32a) capable of converting a light signal that it receives into an electrical signal, each acquisition module (32ij) being capable of generating an elementary detection signal (Sde^) as a function of the electrical signal(s) converted by the photodetector(s) (32a) of the elementary acquisition module (32ij); • an optical focusing device (33) capable of receiving the light beams (F2), said optical focusing device (33) being arranged opposite the plurality of input faces of the elementary acquisition modules (3¾); - a calculation unit (4) capable of receiving the elementary detection signals (Sdc,) generated by the elementary acquisition modules (3¾) and capable of detecting in each elementary detection signal (Sdc,) received the presence of a sequence of predetermined data; characterized in that the optical focusing device (33) has an optical axis (X), in that the elementary acquisition modules (3¾) are arranged on either side of said optical axis (X) and in that at least one second elementary acquisition module (3¾) further from the optical axis (X) than a first elementary acquisition module (3¾) has dimensions greater than those of said first elementary acquisition module (3¾). Telemetry system (1) according to claim 1, characterized in that the dimensions of the input face of the second elementary acquisition module (32ij) are greater than the dimensions of the input face of the first elementary acquisition module (3¾). Telemetry system (1) according to one of claims lou 2, ca- characterized in that the dimensions of the input face of each elementary acquisition module (32^) increase with the distance of said elementary acquisition module (32îj) from the optical axis (X) of the optical focusing device (33).

4. Telemetry system (1) according to one of claims 1, 2 or 3, characterized in that the plurality of elementary acquisition modules (32j) comprises a first (321) and a second group (322) of elementary acquisition modules (32^), the first elementary acquisition module belonging to the first group (321) of elementary acquisition modules (32^), the second elementary acquisition module belonging to the second group (322) of elementary acquisition modules (32^), in that the dimensions of the input face of each elementary acquisition module (32,j) of the second group (322) are greater than or equal to the dimensions of the input face of each elementary acquisition module (32ij) of the first group, and in that the dimensions of the input face of each elementary acquisition module (32ij) of the first group (321) are constant and the dimensions of the input face of each acquisition module elementary (32,j) of the second group (322) increase with the distance of said elementary acquisition module (32ij) from the optical axis (X) of the focusing device (33).,

5. Telemetry system (1) according to one of claims 1, 2 or 3, characterized in that the plurality of elementary acquisition modules (32j) comprises a first (321) and a second group (322) of elementary acquisition modules (32^), the first elementary acquisition module belonging to the first group (321) of elementary acquisition modules (32^), the second elementary acquisition module belonging to the second group (322) of elementary acquisition modules (32^), in that the dimensions of the input face of each elementary acquisition module (32,j) of the second group (322) are greater than the dimensions of the input face of each elementary acquisition module (32j) of the first group (321), and in that the dimensions of the input face of each elementary acquisition module (32ij) of the first group (321) and of the second group (322) are constant.

6. Telemetry system (1) according to one of claims 4 or 5, characterized in that the first (321) and second groups (322) of elementary acquisition modules (32j) are coplanar, preferably the first (321) and second groups (322) form a line.

7. Telemetry system (1) according to one of claims 4, 5 or 6, characterized in that the plurality of elementary acquisition modules (32 ij) comprises a third group (323) of elementary acquisition modules (3¾) arranged so that the second group (322) is juxtaposed with the first group (321) on one side of the optical axis (X) of the optical focusing device (33) and the third group (323) is juxtaposed with the first group (321) on the other side of the optical axis (X) of the optical focusing device (33).

8. Telemetry system (1) according to the preceding claim, characterized in that the dimensions of the elementary acquisition modules (32^) of the second (322) and third groups (323) are substantially similar.

9. Telemetry system (1) according to one of the preceding claims, characterized in that the number of photodetectors of the second elementary acquisition module (32ij) is greater than or equal to the number of photodetectors of the first elementary acquisition module (3¾).

10. Telemetry system (1) according to the preceding claim, characterized in that the pitch separating at least two adjacent photodetectors of the second elementary acquisition module (32ij) is greater than the pitch separating at least two adjacent photodetectors of the first elementary acquisition module (3¾).

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