FR3055745A1 - METHOD FOR CONTROLLING AN OPTICAL PHASE NETWORK AND METHOD FOR RECOGNIZING AN OBJECT USING SUCH A NETWORK AND AN OPTICAL SYSTEM - Google Patents

Abstract

A method for controlling an optical phase grating (102), as follows: - introducing a measurement signal (116) which represents the intensity distribution and / or the wavefront of a light signal (104) transmitted by the optical phase grating (102); - comparing the measurement signal (116) with a reference signal to determine a value (120) of the difference between the measurement signal (116) and the reference signal, and - generating a control signal (124) for controlling the optical phase grating (102) using the value of the gap (120).

Description

® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY © Publication number: 3,055,745 (to be used only for reproduction orders)

©) National registration number: 17 58087

COURBEVOIE

©) Int Cl ⁸ : H 01 Q 19/17 (2017.01), H 01 Q 3/26

A1 PATENT APPLICATION

©) Date of filing: 01.09.17. © Applicant (s): ROBERT BOSCH GMBH— DE. (30) Priority: 05.09.16 DE 102016216711.1. ©) Inventor (s): CASPERS JAN NIKLAS, FIESS REIN- HOLD and GRAF TOBIAS. (43) Date of public availability of the request: 09.03.18 Bulletin 18/10. ©) List of documents cited in the report preliminary research: The latter was not established on the date of publication of the request. @) References to other national documents ©) Holder (s): ROBERT BOSCH GMBH. related: ©) Extension request (s): @) Agent (s): CABINET HERRBURGER.

METHOD FOR CONTROLLING AN OPTICAL PHASE NETWORK AND METHOD FOR RECOGNIZING AN OBJECT USING SUCH A NETWORK AS WELL AS AN OPTICAL SYSTEM.

FR 3 055 745 - A1 (5g) Method for controlling an optical phase network (102), consisting of:

- introducing a measurement signal (116) which represents the intensity distribution and / or the wavefront of a light signal (104) emitted by the optical phase network (102),

- comparing the measurement signal (116) with a reference signal to determine a value (120) of the difference between the measurement signal (116) and the reference signal, and

- generating a control signal (124) to control the optical phase network (102) using the value of the difference (120).

i

Field of the invention

The present invention relates to a device or a method for controlling an optical phase network as well as a device for its implementation and a computer program for the execution of the method.

State of the art

In radar technique, separate antennas are grouped with individual phase or amplitude control, that is, phase array antennas. These techniques belong to the state of the art.

In telecommunications, it is also possible to use phase array antennas because they have better performance, are lighter, less bulky and allow flexible shaping of the antenna profile.

In the field of optical wavelengths, especially in the infrared field, research is currently very much interested in the application of optical phase arrays to integrated photonic elements. Possible solutions for the realization of optical phase networks with CMOS processes (CMOS = complementary metal-oxide-semiconductor) or SOI processes (SOI = Silicon on insulator) have been sought for example within the framework of the SWEEPER program (SWEPPER = Short-Range, Wide Fieldof-View Extremely agile, Electronically Steered Photonic Emitter) from DARPA.

Purpose of the invention

The aim of the present invention, starting from this context, is to develop a method for controlling an optical phase network, a method for recognizing an object using an optical phase network and a device. applied to this process as well as an optical system and a computer program.

Presentation and advantages of the invention

To this end, the subject of the invention is a method for controlling an optical phase network, comprising the following steps consisting in:

introduce a measurement signal which represents the intensity distribution and / or the wavefront of a light signal emitted by the optical phase network, compare the measurement signal with a reference signal to determine the value of the difference between the measurement signal and the reference signal, and generating a control signal for controlling the optical phase network using the value of the difference.

An optical phase array can be an array formed by several antenna elements controlled separately to emit light rays, which makes it possible to superimpose light rays emitted by the antenna elements having a certain radiation characteristic, by the optical phase. The radiation characteristic can be modified by controlling the antenna elements, for example by modifying the adjustment of the amplitude or the phase of the different antenna elements without having to move the optical phase network for this. The optical phase network can for example be produced according to a method of the technique of silicon-based semiconductors.

The measurement signal is for example a reaction signal decoupled from the light signal by an appropriate optical installation. For example, for the measurement signal, this can be the signal from a wavefront sensor also known as a Shack-Hartmann sensor. The measurement signal can also represent a signal generated by a transformation into Fourier optics. A light signal can be an electromagnetic signal in the visible light range. A reference signal is for example a set value of a radiation profile of the optical phase network. The intensity distribution is, according to the embodiment, an intensity distribution in the near or far radiation area of the phase grating. For example, the control signal can be generated to control different antenna elements of the optical phase array so as to compensate or correct for deviations.

The solution as presented is based on the consideration that by an appropriate reaction, it is possible to directly monitor a radiation profile or a phase distribution of an optical phase network and, if necessary, to correct it actively. This makes it possible to remedy the oscillations of the radiation profile or of the phase distribution resulting from the influences of the environment or of the heat given off by the operation. The reaction can for example be carried out with measurements of the radiation area (far radiation area) to determine an intensity distribution of the far radiation area or in addition or alternatively, by a measurement of the wave front. This solution has the advantage that it is possible to monitor effectively during operation, the distribution of light emitted and for example to correct it by modifying the phase distribution of certain antennas of the optical phase array.

As an exemplary embodiment, one can make such a correction by using array configurations or also actively with optimization algorithms by relying on the Gerschberg-Saxton algorithm for diffracting phase elements or evolving algorithms. As a variant, instead of an active correction of the phase elements, the deviations observed with respect to the ideal distribution are compensated for based on the measurement results of a control loop in the exploitation of the data.

According to one embodiment, in the recording step, a signal which represents the intensity distribution of the light signal in the radiation area distant from the optical phase network is recorded as a measurement signal. This makes it possible to efficiently calculate the corrections necessary in the phase distribution of the optical phase network by relying on the mathematical relationship between the Fourier transformation and the Fraunhofer diffraction.

According to another development, in the comparison step, the measurement signal is compared to a reference intensity distribution representing a signal as a reference signal and the lateral offset between the intensity distribution represented by the measurement signal is determined. and the reference intensity distribution. In addition or as a variant, the reference signal represents a reference wavefront and the measurement signal is compared to the reference signal to de3055745 complete the lateral offset between the wavefront represented by the measurement signal and the edge reference waveform as the deviation value. This makes it possible to precisely determine the value of the deviation with relatively reduced calculation means.

Advantageously, in the recording step, a signal whose phase distribution is practically equal to the phase distribution of the light signal is recorded as a measurement signal. This minimizes inaccuracies in the comparison of the measurement signal to the reference signal. This guarantees high process precision.

In addition, in the generation step, you can generate the control signal to correct the deviation. This makes it possible to meet the objectives concerning the light distribution emitted by the optical phase network.

The subject of the invention is also a method of recognizing an object using an optical phase network, the method consisting in:

record a measurement signal which represents an intensity distribution and / or a wave front of a light signal emitted by the optical phase network and of a detector signal which represents the part of the light signal reflected by the object, compare the measurement signal with a reference signal to determine a deviation value of a deviation between the measurement signal and the reference signal, and use the detection signal using the deviation value to recognize the 'object.

A detector signal is a signal generated by a detection installation (or detector installation) such as for example a Lidar sensor, Ladar sensor or any other optical sensor.

This process can be implemented for example in the form of a program or a circuit or even in a mixed form combining a program and a circuit, for example in a control device.

The invention as presented also relates to a device for carrying out the steps of a variant of the method in appropriate installations, for controlling or applying them. These variant embodiments of the invention in the form of a device make it possible to quickly and effectively solve the problem posed by the invention.

The device comprises at least one search unit for processing the signals or the data, at least one memory unit for recording the signals or the data, at least one interface with a sensor or an actuator for recording the sensor signals supplied by the sensor or for transmitting data signals or control signals to the actuator and / or at least one communication interface for recording or transmitting data which are integrated in a communication protocol. The search unit is for example a signal processor, a microcontroller or the like and the memory unit is a flash memory, an EPROM memory or a magnetic memory. The communication interface makes it possible to record the data by a wireless link and / or by a cable and to transmit them under the same conditions, the communication interface recording or transmitting the data linked to a cable; this data is for example recorded in electrical or optical form from an appropriate data transmission line or is transmitted in a corresponding data transmission line.

A device according to the invention is an electrical device which processes the sensor signals and as a function of these, it generates control and / or data signals. The device can include an interface produced in the form of a circuit and / or a program. In the case of an embodiment in the form of a circuit, the interfaces can for example be part of an ASIC system which contains different functions of the device. However, it is also possible that the interface includes integrated circuits or is composed at least in part of discrete components. In the case of implementation by program, the interfaces can be program modules residing for example on a microcontroller alongside other program modules.

According to an advantageous development, the device controls a vehicle. The device uses, for example, sensor signals such as acceleration, pressure, steering angle signals or signals from surrounding field sensors. The control is done by actuators such as brake or steering actuators or by the engine control unit of the vehicle.

The invention also relates to an optical system having:

an optical phase network for emitting a light signal, a measuring installation for measuring the intensity distribution and / or the wavefront of the light signal, and a device according to the above embodiment.

The measuring installation is for example an optical sensor.

According to one embodiment, the optical system comprises an optical installation for decoupling the reaction signal from the light signal. The optical installation is carried out to guide the feedback signal on the measurement installation. Correspondingly, the measuring installation detects the intensity distribution and / or the wavefront using the feedback signal. The optical installation is for example a beam splitter element, a lens element, in particular a collecting lens or even a Fourier lens, a mirror element, a holographic element or any other refracting, diffracting or reflecting element or a combination of several optical components. For example, the optical installation can be in the Fraunhofer structure for the observation of an intensity distribution of radiation area far from the optical phase network. This embodiment guarantees a reaction as precise as possible.

According to another embodiment, the optical installation comprises at least one beam splitter element, at least one mirror element, at least one lens element or a combination formed from at least two of the above elements. A beam splitter element is for example a beam splitter cube or a semi-transparent mirror. A lens element is for example a collecting lens. In particular, the lens element can function as a Fourier optic. This embodiment corresponds to an economical optical installation with reduced means.

It is also advantageous according to the invention to have a computer program product or a computer program with a program code recorded on a medium readable by a machine or memory medium such as a semiconductor memory, a hard disk or an optical memory for executing, applying and / or controlling the steps of the method according to one of the embodiments described above, in particular when the product programs or more simply the program is executed by a computer or a device of this type.

Drawings

The present invention will be described below in more detail with the aid of examples of a method for controlling an optical phase network and a device for its implementation represented in the appended drawings in which:

FIG. 1 is a diagram of an exemplary embodiment of an optical system, FIG. 2 is a diagram of another exemplary embodiment of an optical system, FIG. 3 is a diagram of the operation of the Fraunhofer structure for the observation of the distribution of the intensity in the radiation area, FIG. 4 is a schematic representation of an exemplary embodiment of an optical installation, FIG. 5 shows a flowchart of an exemplary embodiment of a method for controlling an optical phase network, and FIG. 6 shows a flowchart of an exemplary embodiment of a method for recognizing an object using an optical phase network.

Description of embodiments

FIG. 1 schematically shows an exemplary embodiment of an optical system 100 as a block diagram, for detecting a deviation of the light signal 104 emitted by an optical phase network 102 from the ideal radiation. The optical system 100 comprises a first block 106 formed by a transmitter unit in the form of an optical phase network 102 (abbreviated as OPA network) and a receiver unit in the form of a measurement installation. 108 to measure an intensity distribution or in addition or alternatively, the wavefront of the light signal 104, for example using a Fresnel lens and a second block which represents a device 112 for electronic signal processing and regulation of the optical phase network 102.

The device 112 includes an input unit 114 for inputting the measurement signal 116 generated by the measurement installation 108 and which represents the intensity distribution or the wavefront of the light signal 104. The input unit 114 transmits the measurement signal 116 to a comparison unit 118 to compare the measurement signal 116 with a reference signal. As a result of the comparison, the comparison unit 118 generates a difference 120 which represents the difference between the measurement signal 116 and the reference signal, i.e. the difference between the actual value and the value setpoint of the output signal 104 of the optical system 100. The comparison unit 118 transmits the difference (or value of the difference) 120 to a generator unit 122 made for example as an electronic component for regulating the phase profile of the network optical phase 102.

According to an exemplary embodiment, the comparison unit 118 generates the deviation 120 using an algorithm in the context of a correction method to correct the deviation. The generator unit 122 uses the offset 120 to generate a control signal 124 used to control the optical phase network 102 by transmitting this signal to it.

According to this exemplary embodiment, the optical system 100 comprises an optical installation 126, also called the optical subsystem. The optical installation 126 divides the light signal 104 into a useful light signal 128 which represents a determined useful light distribution and a reaction signal 130 for the regulation loop used to regulate the optical phase network 102; the feedback signal 13055745 tion 130 is led by the optical installation 126 to the measurement installation 108. Thus, the measurement installation 108 generates the measurement signal 116 using the feedback signal 130. In particular, the installation optical 126 decouples the reaction signal 130 from the light signal 104 so that the phase distribution of the measurement signal 116 practically corresponds to the phase distribution of the light signal 104.

FIG. 2 is a diagram of an exemplary embodiment of an optical system 100. The optical system 100 corresponds practically to the optical system described above with the aid of FIG. 1. The figure shows a block diagram for detecting a difference between a radiation profile of the optical phase network 102 and a corresponding correction in the detection of objects and the detection operation of an optional detector installation 200 of the optical system 100 such as a Lidar sensor. The optical system 100 comprises a transmission and reception unit, a subsystem for monitoring the signal as well as an electronic regulation loop for generating the signal and regulating it. The detection installation 200 detects the part 204 of the light signal 104 emitted by the optical phase network 102, and returned by the scenario 202, more precisely detecting the useful light signal 128 obtained by the division of the light signal 104 by the installation optical 126. The detection installation 200 generates a detection signal 206 representing the scenario 202 and sends this to the operating unit 208 of the device 112 which also receives the difference 120 supplied by the comparison unit 118. The operating unit 208 uses the detection signal 206 using the deviation 120 to recognize the scenario 202.

Figure 3 is a schematic representation of the operation of a Fraunhofer 300 structure for the observation of the intensity distribution in the so-called Fraunhofer radiation area, as can be measured for example using the measurement installation described above using FIGS. 1 and 2. The structure presented in FIG. 3 is the basic structure of the optical installation described above using FIGS. 1 and 2. The structure of Fraunhofer 300 comprises a diffraction structure 302 for diffracting the light ray 304. The diffraction structure 302 is located at the distance ίο (d) from a Fourier lens 306 of focal length (f). The focal plane 308 of the Fourier lens 306 is indicated by a vertical line.

FIG. 4 is a schematic representation of an optical installation 126 according to an exemplary embodiment. The optical installation 126 is the optical installation described above with the aid of FIGS. 1 to 3. The figure shows an example of a schematic structure for monitoring the intensity distribution in the radiation field of the optical phase network 102 , also called distribution of the intensity of the radiation field. The optical installation 126 according to this exemplary embodiment corresponds to the principle described above with the aid of FIG. 3 of the Fraunhofer structure for applying an optical transformation, of Fourier. Here, the optical installation 126 comprises for example a beam splitter element 400 for dividing the light signal 104 emitted by the optical phase network 102 to have the reaction signal 130 and the useful light signal 128 with a corresponding distribution of light. useful. A mirror element 402 is installed opposite the beam splitter element 400 to guide the reaction signal 130 on the lens element 404, here a Fourier lens. The lens element 404 directs the feedback signal 130 to the detection facility 200 which is in the rear focal plane of the lens element 404.

An exemplary embodiment of a structure for regulating the optical phase network 102 by radiation field measurements will be described below with the aid of FIG. 4 and in terms different from those used previously.

The optical phase network 102 is followed by an optical component such as the beam splitter element 400 which decouples part of the emitted light 104 from the beam. Optionally, use is made of the mirror element 402 which can be a surface plane or a free-form surface to compensate for the optical path lengths and to a very large extent obtain the phase reference of the interference pattern. The radiation distribution is generated with a Fourier lens as lens element 404 on the detection installation 200. The position of the useful light distribution is for example obtained using a camera. The lateral offsets are made according to the offset, for example by an a posteriori adjustment of the optical phase network 102 with a linear phase component:

F [# (x, y) e ^{2iti (az +} ^] = G (fe _x - a, k ₂ - b) in this formula, the following expression:

CO

G (7q; A: ₂ ) = F [^ (%, y) j = JJg (x, y) e dxdy is the Fourier transform.

FIG. 5 shows a flowchart of an exemplary embodiment of a method 500 for controlling an optical phase network. The method 500 is applied for example in connection with the device described above with the aid of FIGS. 1 to 4. According to the diagram, in step 510, the measurement signal generated by the measurement installation of the optical system. According to the exemplary embodiment, the measurement signal represents an intensity distribution, in particular an intensity distribution in the radiation area or else the wavefront of the light emitted by the optical phase grating. In step 520, the measurement signal is compared to a reference signal to determine the deviation. Finally, in step 530, the control signal is generated using this deviation value.

FIG. 6 shows the flowchart of an exemplary embodiment of the method 600 for recognizing an object using an optical phase network. The method 600 can be applied for example in connection with the device described above with the aid of FIGS. 1 to 4. In step 610, the measurement signal generated by the measurement system of the optical system is applied as well as the detector signal supplied by the detection installation. According to the exemplary embodiment, the measurement signal represents an intensity distribution, in particular an intensity distribution in the radiation region or the wavefront of the light emitted by the optical phase grating. In step 620, the measurement signal is compared with the reference signal to determine the deviation (value of the deviation). Finally, in step 630, the detection signal is used by using the comparison value to recognize the object.

Different embodiments of the solution presented above will be summarized again below in other words.

According to an exemplary embodiment, a portion of the light 104 emitted by the phase network 102 is deflected using the beam splitter element 400 such as a transparent mirror, a beam splitter cube or a diffracting or holographic element. However, care must be taken to respect a relative phase distribution to reduce the influence of the phase distribution through decoupling. Respect for the relative phase distribution is made possible, for example if the mirror element 402 is used. Depending on the opening and the divergence of the radiated light 104, according to an exemplary embodiment, at Using a Fraunhofer structure such as that presented for example in FIGS. 3 and 4, an optical transform, of Fourier, is produced to observe the distribution of the intensity of the field in the rear focal plane of the Fourier lens 404. Instead of the conventional refractive lens, it is also possible to use a diffracting or holographic element or else an array of microlenses as lens element 404. For example, the use of an array of microlenses presents d Other possibilities for measuring the wavefront and determining the deviation from the setpoint set in advance, for example using a Hartmann-Shack sensor.

According to another exemplary embodiment, the reflections which occur on the optics of the optical system 100 are used. First of all, it is necessary to guarantee that the reflections retain the phase distribution of the light signal 104 emitted. On the other hand, it must be ensured that the reflections do not arrive directly on the phase network 102 but on the detection installation 200 which is right next to it. The detection installation 200 can for example create a network of detectors.

The advantage of a far field strength measurement is the mathematical relationship between the Fourier transformation and Fraunhofer diffraction. Thus, by relying on the Fraunhofer structure described above for a far field measurement, the correction necessary in the phase distribution is determined by calculation with an implementation of relatively reduced means and by example we optimize the phase distribution using an appropriate algorithm. For example, in the event of a lateral shift of an optical distribution, target, that is to say the optical beam in the radiation area, with respect to the setpoint state, is recognized by the regulation loop proposed here and this is corrected by an additional linear phase component. In the case of a direct determination of the wavefront, such as using a HartmannShack sensor, there will for example be a total correction of the phase distribution in the optical phase network 102 to correct the local measurement deviations of the wavefront.

According to another exemplary embodiment, the optical system

100 also includes a detection component such as a detection installation 200 to compensate for the determined difference between the set point distribution and the actual distribution in a given operation, on the detection side.

An important difference compared to the structures of

Fraunhofer prior to diffractive optical elements lies in the relatively large divergence and in the combination between the probably curved wavefront phase of the different transmitters and the induced phase distribution of the phase network 102.

NOMENCLATURE OF MAIN ELEMENTS 100 102 104 106 108 112 114 116 118 120 122 124 126 128 130 200 202 204 206 208 300 302 304 306 400 402 404 500 510-530 600 Optical system Optical phase network Light signal First block Measuring installation Electronic signal processing device Entrance unit Measuring signal Comparison unit Deviation / deviation value Generating unit Control signal Optical installation Useful light signal Reaction signal Detection facility Scenario Reflected part of the light signal Detector signal Operating unit Fraunhofer's structure Diffraction structure Light bleam Fourier lens Beam splitter element Mirror element Lens element / Fourier lens Method for controlling an optical phase network Process steps 500 Method of detection / recognition of an object by a 610-630 d f optical phase network Process steps 600 Distance from the Fourier lens Focal distance

Claims (12)

1) Method (500) for controlling an optical phase network (102), comprising the following steps consisting in: introduce (510) a measurement signal (116) which represents the intensity distribution and / or the wave front of a light signal (104) emitted by the optical phase network (102), compare (520 ) the measurement signal (116) to a reference signal to determine the value (120) of the difference between the measurement signal (116) and the reference signal, and 10 - generate (530) a control signal (124) to control the optical phase network (102) using the value of the deviation (120). 2 °) A method (500) according to claim 1, according to which, in the recording step (510), the measurement signal (116) is recorded 15 a signal which represents an intensity distribution of the light signal (104) in the radiation area of the optical phase network (102). 3 °) Method (500) according to one of claims 1 and 2, according to which, in the comparison step (520), the measurement signal is compared 20 (H6) to a signal representing a reference intensity distribution and / or a reference wavefront as the reference signal to determine as deviation value (120) the lateral offset between the intensity distribution shown by the measurement signal (116) and the reference intensity distribution and / or between the wavefront 25 representing the measurement signal (116) and the reference wavefront. 4 °) Method (500) according to one of the preceding claims according to which, in the recording step (510), a signal whose phase distribution is practically equal to 30 is recorded as the measurement signal (116). the phase distribution of the light signal (104). 5 °) Method (500) according to one of the preceding claims according to which, in the generating step (530), the control signal (124) is generated to correct the deviation. 6 °) Method (600) of detecting an object (202) using an optical phase network (102), comprising the following steps consisting in: recording (610) a measurement signal (116) which represents an intensity distribution and / or a wavefront of a light signal (104) emitted by the optical phase network (102) and of a signal detector (206) which represents the part (204) of the light signal (104) reflected by the object (202), comparing (620) the measurement signal (116) with a reference signal to determine a deviation value ( 120) of a difference between the measurement signal (116) and the reference signal, and exploit (630) the detection signal (206) by using the difference value (120) to recognize the object (202) . 7 °) device (112) comprising units (114, 118, 122; 208) for carrying out the method (500) according to one of claims 1 to 5 and / or the method (600) according to claim 6 and / or order this process. 8 °) Optical system (100), characterized in that it comprises an optical phase network (102) for emitting a light signal (104), a measurement installation (108) for measuring an intensity distribution and / or a wave front of the light signal (104), and a device (112) according to claim 7. 9 °) optical system (100) according to claim 8, comprising an optical installation (126) for decoupling a reaction signal (130) from the light signal (104), * the optical installation (126) guiding the reaction signal ( 130) on the measuring installation (108), and * the measuring installation (108) measuring the intensity distribution and / or the wavefront using the reaction signal (130). 10 °) optical system (100) according to claim 9, wherein the optical installation (126) comprises at least one beam splitter element (400) and / or at least one mirror element (402) and / or at least a lens element (404). 11 °) computer program for applying the method (500) according to one of claims 1 to 5 and / or the method (600) according to claim 6. 12 °) Memory medium readable by a machine and containing the recording of the computer program according to claim 11.