DEVICE AND METHOD FOR DETECTING AN OBJECT

Abstract

DEVICE AND METHOD FOR DETECTING AN OBJECT The invention relates to a method for detecting an object comprising the following steps: the generation of a control signal (31) to produce the emission of a light signal (111) by a phototransmitter (110); characterized in that said generated light signal (111) is a periodic signal at a predetermined frequency; detection by a photodetector (2) of a light comprising at least one reflected signal (112), said reflected signal comprising a part of the light signal (111) emitted by the photoemitter (110) which is reflected on an object (103) and arrives at the photodetector (2) and the production of a detection signal (41); filtering said detection signal (41) to generate a filtered signal (46); measuring the amplitude of the filtered signal (46) to generate an amplitude indicator (51) of said filtered signal (46); detecting the presence of an object (103) from said amplitude indicator (51).Figure for the abridged version: Fig.3.

Description

Title of the invention: DEVICE AND METHOD FOR DETECTING AN OBJECT Scope of the invention

[0001] The invention relates to a method and an associated electronic device for the detection of an object, in particular an object in the near field in front of a detection surface. State of the art

[0002] Today there are devices for detecting one or more objects based on the use of optics.

[0003] For example, document FR3103341 describes the use of a device such as a camera or a depth camera to detect a user's hand or the recognition of a hand gesture.

[0004] One drawback of this type of device is that the detection cone or field of view of such a camera is narrow and defined by its optical lens. Consequently, this type of device is not suitable for detecting an object in the near field, that is, at a height almost zero relative to the detection device.

[0005] To overcome this drawback, document EP2843509 describes a device comprising a peripheral border of a screen for estimating the coordinates of an object above the screen. This device emits infrared light onto the object and detects the light reflected by said object to detect its presence.

[0006] However, a drawback of this device is that the light detected by the photodetector is a sum of the light reflected from the photoemitter and ambient light emitted by a stray light source. In most applications, and as illustrated in [Fig. 1], the portion of the detected light due to reflected light R from the object is negligible or very small compared to the portion due to ambient light L. It is possible to measure the difference in light detected by the photodetector when the photoemitter is switched off and then switched on. However, since the variation can be very small, the calculated value is not sufficiently precise to obtain satisfactory results.

[0007] There is a need for a method and device for detecting an object in the near field capable of obtaining a sufficiently accurate estimate even in the presence of ambient light or stray light sources. Summary of the invention

[0008] According to a first aspect, the invention relates to a method of detecting an object, in particular an object located in the detection field of an electronic device.

[0009] The method includes a step of generating a control signal to produce the emission of a light signal by a phototransmitter. The generated light signal is a periodic signal at a predetermined frequency.

[0010] Said method includes the detection by a photodetector of a light comprising at least one reflected signal, said reflected signal comprising a part of the light signal emitted by the photoemitter which is reflected on an object and arrives at the photodetector and the production of a detection signal.

[0011] Said method includes a step of filtering said detection signal so as to retain, from the detection signal produced, only the frequencies included in a predetermined frequency range to generate a filtered signal; said predetermined frequency being included in said predetermined frequency range.

[0012] Said method includes a measurement of the amplitude of the filtered signal to generate an amplitude indicator of said filtered signal.

[0013] According to one embodiment, the method includes a step of detecting the presence of an object from said amplitude indicator.

[0014] According to one embodiment, the light detected by the photodetector further includes ambient light.

[0015] According to one embodiment, the intensity of said surrounding light captured by the detector is significantly greater than the intensity of the reflected signal captured by the detector.

[0016] According to one embodiment, the measurement step further includes a substep of converting the filtered signal into a constant converted signal.

[0017] According to one embodiment, the converted signal is generated so as to be constant at least for the time of the measurement of the signal amplitude.

[0018] According to one embodiment, the conversion of the filtered signal into a constant signal is carried out synchronously with the control signal.

[0019] According to one embodiment, the conversion of the filtered signal into a constant signal is carried out by a sample-and-hold circuit.

[0020] According to one execution mode, the detection of the presence of an object includes comparing the amplitude indicator to a predefined threshold value.

[0021] According to one embodiment, the step of detecting the presence of an object includes calculating a distance and / or position data of said object from at least one amplitude indicator.

[0022] According to one embodiment, the calculation of a distance value is performed by comparing the amplitude indicator with one or more predetermined threshold values. In another embodiment, the distance value is calculated using a predetermined mathematical function such as a calibration function.

[0023] According to a second aspect, the invention relates to an electronic device for detecting an object.

[0024] In one embodiment, the device includes software and / or hardware means for implementing the method according to the invention.

[0025] In one embodiment, the device includes a controller adapted to produce a control signal, having a predetermined periodic frequency, and intended to be used to drive a phototransmitter in order to cause the phototransmitter to emit a periodic light signal having a predetermined periodic frequency.

[0026] In one embodiment, the device includes a photodetector designed to produce a light detection signal comprising at least one reflected signal, said reflected signal comprising a portion of the light emitted by the photoemitter which is reflected off an object and arrives at the photodetector.

[0027] In one embodiment, the device includes a signal processing unit adapted to perform the filtering of said detection signal so as to retain, from the detection signal, only the frequencies included in a predetermined frequency range to generate a filtered signal; said predetermined frequency being included in said predetermined frequency range.

[0028] In one embodiment, the device includes a unit for measuring the amplitude of the filtered signal to generate an amplitude indicator of said filtered signal.

[0029] In one embodiment, the device includes a computing unit configured to detect the presence of an object from said amplitude indicator.

[0030] In one embodiment, the signal processing unit includes a high-pass filter to perform the signal filtering step, said high-pass filter being designed so that the frequency range between its cutoff frequencies includes the predetermined frequency of said light signal emitted by the phototransmitter.

[0031] In one embodiment, the device further includes at least one phototransmitter designed to emit a signal according to the control signal emitted by the controller. Brief description of the figures

[0032] Other features and advantages of the invention will become apparent from the following detailed description, with reference to the accompanying figures, which illustrate:

[0033] [Fig-1]: a graphical representation of the intensity of the signal detected by a photo detector according to prior art methods.

[0034] [Fig.2]: a graphical representation of the intensity of the signal detected by a photodetector according to an embodiment of the invention.

[0035] [Fig.3]: a schematic representation of an electronic device according to an embodiment of the invention.

[0036] [Fig.4]: a schematic representation of a signal measurement unit according to an embodiment of the invention.

[0037] [Fig.5]: a schematic representation of a calculation unit according to an embodiment of the invention.

[0038] [Fig.6]: a logic diagram representing a mode of execution of the method according to the invention.

[0039] [Fig.7]: a simplified representation of the values ​​of the different signals during the detection of an object according to an execution mode of the method according to the invention.

[0040] [Fig.8]: a simplified representation of an electronic assembly according to an embodiment of the electronic device according to the invention in which the unit of measurement includes a sample-holding component.

[0041] [Fig.9]: a schematic representation of the device according to an embodiment in which a plurality of photodetectors are connected in parallel and each photodetector is connected to a different circuit in parallel comprising a processing unit and a measuring unit.

[0042] [Fig. 10]: a schematic representation of the device according to an embodiment in which a plurality of photodetectors are each connected to a processing unit in parallel.

[0043] [Fig. 11]: a schematic representation of the device according to an embodiment in which a plurality of photodetectors are connected to a single group consisting of a single processing unit, a single measuring unit and a single computing unit. Definitions

[0044] By "photodetector", we mean any type of structural means enabling the detection of a light intensity and the generation of a signal according to said detected intensity.

[0045] By "photoemitter" is meant any type of means capable of emitting light radiation when activated, for example by application of a current or a voltage.

[0046] By "significantly greater" is meant at least 2 times greater, at least 10 times greater or preferably at least 100 times greater.

[0047] By "computing unit", we preferably mean any type of software and / or hardware means enabling the execution of a method or process comprising an electronic circuit including at least one processor or computer coupled to at least one data medium, preferably non-transient, such as a memory, and on which is encoded an algorithm or a sequence of instructions executable by the processor to execute said method by the processor.

[0048] By "substantially" followed by a numerical value means said numerical value + / - 5% or 10%.

[0049] By “an object located in the detection field” is meant an object located in front of a detection surface illuminated by the photoemitters when the latter are switched on so that the reflected rays reach at least one photodetector. Alternatively, it can simply be understood as an object within the light beam generated by the photoemitters of the detection surface when the latter are switched on or activated.

[0050] By "luminous" we mean any signal in the visible, near or far infrared or ultraviolet range.

[0051] By "constant signal," it is meant that the signal is constant during the measurement of its amplitude, for example, during an analog-to-digital conversion. The measurement duration can be from 20 periods of the control signal to a fraction of a period, such as 1 / 10 of a period or 1 / 20 of a period. The signal is considered constant when its amplitude varies, during the measurement period, by less than 25%, preferably by less than 1%. Detailed description of the invention

[0052] An example of a device is described below with reference to the figures. Detection surface

[0053] According to a first aspect, the invention relates to an electronic device.

[0054] The electronic device includes at least one photodetector 2.

[0055] The electronic device may include or be coupled to at least one photoemitter 110. Preferably, the photoemitters 110 are designed to emit photons by electroluminescence. The photoemitters may also include fluorescent tubes or incandescent light-producing means such as an incandescent lamp. The photoemitters 110 are preferably designed to emit light rays in a predefined wavelength range. The photoemitters may include light-emitting diodes (LEDs) or laser emission devices.

[0056] The photodetectors 2 are designed to detect a light beam. Preferably, at least one photodetector 2 is designed to detect a light beam emitted by the plurality of photoemitters 110. The photodetectors 2 are designed to transform the absorbed light in a range of wavelengths into a measurable quantity such as an electric current or an electric voltage.

[0057] The photodetectors 2 and the photoemitters 110 are arranged such that a light beam emitted by a photoemitter and reflected by an object 103 arrives directly at the photodetector 2 without being reflected by another object. Preferably, the photodetectors 2 and the photoemitters 110 are arranged on the same side of a surface of the electronic device 1.

[0058] An object is considered to be in the detection field of the device when the rays 111 emitted by the photoemitter 110 directly (i.e. without reflection) reach said object 103 and the rays 112, originating from the photoemitter 110, and reflected by the object directly reach the photodetector.

[0059] The photoemitters 110 are designed to emit photons by electroluminescence. The photoemitters 110 are preferably designed to emit light rays in a range of predefined wavelengths.

[0060] Preferably, the photoemitters 110 are designed to emit infrared light radiation.

[0061] The photodetectors 2 are designed to detect a light beam emitted by the plurality of photoemitters 110. The photodetectors 2 are designed to transform the absorbed light in a range of wavelengths into a measurable quantity such as an electric current or an electric voltage. The photodetectors are designed to produce an electrical light detection signal whose intensity or power is a function of the detected light intensity.

[0062] The photodetectors 2 include, for example, optical fiber sensors, photodiodes, or light-emitting diodes. Preferably, the photodetectors 2 are infrared light photodetectors such as infrared photodiodes.

[0063] Preferably, the photoemitters are designed so that their cone of light scattering is as small as possible. In one embodiment, the photodetectors are designed to have the smallest possible detection cone.

[0064] The angle formed by the diffusion cone of one or more photoemitters may be different from the angle of the detection cone of one or more photodetectors.

[0065] Preferably, the photodetectors and photoemitters are regularly distributed along the two spatial directions (x,y) of the detection surface, or along a single spatial direction.

[0066] Each photodetector is preferably arranged between at least two photoemitters in the two spatial directions. In one example, the photodetectors and photoemitters are regularly distributed along two orthogonal directions of the plane of the detection surface.

[0067] In one embodiment, a transparent plate or layer arranged to cover the plurality of photoemitters 110 and photodetectors 2 can be integrated. By "transparent," we mean transparent to the light rays emitted by the photoemitters. Such a plate advantageously protects the physical integrity of the components of the detection surface while allowing the outgoing and incoming light rays to pass through. In one example, the covering layer is transparent to infrared rays. In one example, the cover layer is transparent to light rays emitted by photoemitters 110 and to rays in the visible range such as a quartz plate. Controller

[0068] The following description describes a mode of the invention comprising a single photoemitter and a single photodetector, but also applies to the mode comprising a plurality of photodetectors and / or a plurality of photoemitters.

[0069] The electronic device 1 according to the invention comprises a controller 3. The controller 3 is designed to allow control of the photoemitter 110. In one embodiment, the controller 3 is designed to independently control each photoemitter 110. Each photoemitter 110 can therefore be activated (to emit light) or switched off independently of the activation of the other photoemitters 110.

[0070] The controller 2 can also control the intensity emitted by the photoemitter or each photoemitter so as to vary the light intensity emitted by the photoemitter 110.

[0071] The controller 3 may include an electronic circuit connected to a power source. The controller 3 may include an electronic circuit capable of producing a control signal 31.

[0072] The controller 3 produces a control signal 31 to the phototransmitter to produce the emission of a light signal 111 by the phototransmitter in response to said control signal 31.

[0073] The control signal is generated so that the emitted light signal 111 is a signal with a periodic intensity. Generally, the emitted light signal 111 follows a pattern (also called a "phase") comprising a periodic variation in intensity over time. For example, the control signal 31 is generated so that the emitted light signal is a sinusoidal or square wave signal, successively taking on a first value and then a second value greater than the first value. The first value is preferably zero. In other words, the phototransmitter is controlled by the control signal to switch successively from the off state to the on state periodically.

[0074] By "periodically", it is meant that the control signal and / or the light signal emitted 111 follows a unique pattern (also called "phase") repeatedly at a predetermined frequency.

[0075] The control signal 31 can be, for example, a 500 kHz square wave, but it is not limited to this. This control signal 31 is used to control the phototransmitter 110, in response to which said phototransmitter 110 emits light, by infrared example (emitted light signal). The modulation frequency of the emitted infrared light, which can also be called the carrier frequency, depends on the frequency of the control signal 110. In other words, when the phototransmitter 110 is driven by a control signal 31 of 500 kHz, the carrier frequency of the emitted infrared light signal 111 can be 500 kHz or a multiple (or a fraction) of this frequency, for example 250 kHz or 1000 kHz.

[0076] The control signal can be generated as a function of a synchronization signal 33 produced by a synchronization generator 120. The synchronization signal 33 can be generated so as to control the start of a phase of the control signal 31. In another embodiment, the controller includes an internal clock capable of detecting and / or timestamping the start of a phase of the control signal 31.

[0077] In this respect, the synchronization generator 120 or the controller 3 may include a clock. The synchronization generator may generate a first synchronization signal 33 to control the control signal 31 generated by the controller 3 and a second synchronization signal 32 transmitted to the measuring unit described below to allow rectification of the signal synchronously with the control signal and / or the detection signal 4L. Detection Signal Processing Unit

[0078] The device further includes a processing unit 4 for the detection signal 41 produced by the photodetector 2.

[0079] The processing unit is designed to receive, as input, an electrical signal generated by the photodetector and to generate, as output, a filtered signal 46 so as to retain from the input signal only the modulation frequencies of said input signal included in a predetermined frequency range.

[0080] The advantage of this processing unit is that it retains, from the detection signal, only the components of the signal whose frequency is within the predetermined frequency range.

[0081] In a preferred embodiment illustrated in [Fig. 8], the processing unit 4 comprises an electronic circuit including a bandpass filter and / or a bandpass filter and a transimpedance amplifier. Optionally, the processing unit 4 further comprises an electronic circuit including an amplifier 411 for amplifying the signal from the bandpass filter, such as an operational amplifier or a bandpass voltage amplifier with an operational amplifier. One advantage is to increase the amplitude of the filtered signal 46 to improve the quality of the final measurement.

[0082] In the following description, the term "filtered signal" shall refer both to the filtered signal 46 directly from the bandpass filter, and to the filtered signal 461 from an amplifier or other filter using said filtered signal 46 from the bandpass filter band. Unit of measurement

[0083] The device further includes a unit of measurement 5 of the amplitude of the filtered signal 46, one embodiment of which is illustrated in [Fig.4].

[0084] The measuring unit is designed to receive as input the filtered signal 46 from the processing unit 4 and to generate a value 51 which is a function of the amplitude of said filtered signal 46.

[0085] The measured amplitude of the filtered signal advantageously allows us to trace back to the component R corresponding to the reflected signal 112.

[0086] Preferably, the unit of measurement comprises at least one signal converter 52 designed to receive as input the filtered signal 46 comprising a periodic component and to generate in response a constant converted signal. One advantage is to measure the amplitude of a constant converted signal 54 rather than a variable signal.

[0087] By "constant" signal, we mean that the signal is constant or substantially constant at least for the time of the amplitude measurement.

[0088] Several solutions allow the said filtered signal 46 to be converted into a constant converted signal 54. For example, the converter 52 may include an electrical circuit.

[0089] In a first example not shown, the converter 52 includes a rectifier circuit. The rectifier circuit may include at least one diode that only allows the positive phase of the signal to pass. Optionally, the converter also includes a low-pass filter for the signal generated by the rectifier circuit to obtain a signal whose value is proportional to the amplitude of the filtered signal 46. Any other voltage rectifier configuration may be used here to improve the performance of the converter. The converter may thus include an electronic circuit designed for successively applying a square function and then a square root function to the filtered signal 46, such as a transistor and diode circuit and / or operational amplifiers.A person skilled in the art will be able to identify that the rectification circuits that can be applied here are numerous and include in particular precision rectification circuits including an operational amplifier circuit, or a rectification circuit taking into account an offset when the filtered signal 46 is not centered on 0.

[0090] In an alternative or cumulative embodiment, the converter 52 is a synchronous converter. By "synchronous," it is understood that the converter is designed to receive as input a synchronization signal 32 from the synchronization generator and / or from the controller 3. The synchronization signal is generated according to the start time of the phase of the control signal 31. The converter thus synchronizes with the generated control signal 31 to convert the filtered signal 46 into a constant converted signal 54.

[0091] An advantage of converting the filtered signal 46 into a constant converted signal 54 in a manner synchronized with the control signal 51 is to allow filtering of parasitic signals from the surrounding light 113 which would have a frequency equal to or close to the frequency of the control signal 51 (i.e. a frequency within the predetermined frequency range of the filter of the processing unit 4).

[0092] In a second example not shown, the converter 52 includes a rectifier circuit as described above, taking into account said synchronization signal. For example, the rectifier circuit includes a module for centering the detection signal 46 on 0 and a switch configured to divert the signal to a first or second branch depending on the synchronization signal. Preferably, one of the two branches, intended to receive the detection signal 46 when it is negative, includes a module for inverting the sign of said signal (i.e., converting the negative signal into a positive signal). The two branches then rejoin at the signal measurement means. Preferably, a low-pass filter is used between the connection point between the two branches and the measurement means to obtain a constant signal whose value corresponds to the average amplitude of the detection signal 46.

[0093] In a third example shown in [Fig.8], the converter 52 includes an electronic sample-and-hold circuit 521.

[0094] The sample-and-hold electronic circuit 521 is designed to receive the filtered signal 46 as input. The electronic circuit includes a switch 522 capable of closing or opening the circuit. The closing and opening of the switch are controlled by the synchronization signal 32.

[0095] Preferably, the synchronization signal is generated so as to cause the circuit to close over a time interval corresponding to the moment when the phase of the filtered signal 46 reaches a maximum and / or a minimum.

[0096] In one embodiment, the synchronization signal is synchronized with the control signal 31 emitted by the controller to drive the phototransmitter 110.

[0097] When the circuit is closed, a capacitor 523 charges at each successive closing of the switch, until the capacitor is fully charged and generates a constant converted signal 54 representative of the amplitude of the filtered signal 46.

[0098] Preferably, in this embodiment, the circuit includes means for centering the filtered signal 46 on 0 before arriving at the converter.

[0099] This example is described below in more detail with reference to [Fig.7] representing as a function of time the detection signal 41 from the photodetector 2, the filtered signal 46, the synchronization signal 32 and the converted signal 54.

[0100] Initially A, an object is placed in the detection field of the device.

[0101] The photodetector emits a detection signal 41 whose intensity comprises a first component L corresponding to the ambient light emitted by a parasitic source and a second component R corresponding to the light emitted by the photoemitter and reflected by the object. The second component is an intensity varying periodically at a predefined frequency.

[0102] The detection signal 41 is filtered by the processing unit 4 so as to generate a filtered signal 46. The processing unit 4 is designed to retain from the detection signal 41 only the frequencies in a frequency range including the frequency of the second component R.

[0103] In the mode described, the filtering causes a voltage reversal and the centering on 0 of the filtered signal 46.

[0104] The processing unit 4 further includes a signal amplification module 411 for generating an amplified signal 461 from the filtered signal 46.

[0105] The synchronization signal 32 then controls the closing of the sample-and-hold electronic circuit 521. For example, the synchronization signal 32 controls the closing at 1 / 20 of the carrier frequency and is phase-shifted with respect to the control signal 31 so as to cause the circuit to close when the amplified signal 461 is at the peak of its phase. Indeed, the various components such as the filters generate a phase shift of the filtered signal with respect to the detection signal 41 which is characteristic of the component used for filtering and can thus be anticipated.

[0106] In one embodiment, the synchronization signal is generated as a function of the control signal 31 and a pre-recorded offset data.

[0107] During closure, the capacitor 523 charges with each closure until it is fully charged. Once fully charged, the capacitor generates a constant converted signal 54 whose power or amplitude can be measured and transferred to the processing unit 6.

[0108] In a second step B, the object is removed from the detection field of the device. The second component R of the detection signal becomes zero, as does the filtered signal 46. The capacitor 523 then discharges until it generates a zero signal. The measurable value is then also zero.

[0109] In a fourth example not shown, the converter 52 includes a circuit comprising a signal multiplier.

[0110] Said signal multiplier comprises two inputs and one output.

[0111] The circuit is designed so that the signal multiplier receives input through its first The first input receives the filtered signal 46, and the second input receives a synchronization signal. The multiplier is designed to generate a signal whose voltage or current is a product of, respectively, the voltage or current of the filtered signal 46 arriving through the first input and the synchronization signal arriving through the second input.

[0112] In this example, the synchronization signal 32 may comprise a sinusoidal signal generated as a function of the control signal. The synchronization signal is generated so as to be positive when the filtered signal 46 is in a positive phase portion and negative when the filtered signal 46 is in a negative phase portion. Preferably, the synchronization signal is phase-shifted with respect to the control signal in the same way as described for the third example. The generated signal is therefore a rectified positive signal.

[0113] Optionally, the converter further includes a low-pass filter for the signal generated by the multiplier to obtain a signal whose value is proportional to the amplitude of the filtered signal 46.

[0114] In one embodiment, the measuring unit 5 also includes a means for measuring the amplitude of the current and / or voltage of said converted signal 54. Said measuring means preferably includes a voltmeter, an oscilloscope, or any other means known to those skilled in the art for measuring voltage in an electronic circuit. Said measuring means may include an integrator and / or an analog-to-digital converter 53. Said measuring means generates, from said converted signal, a data point representing the amplitude of the filtered signal 46. Said data point may be directly equal to the amplitude of the filtered signal 46, or be proportional to said amplitude, or follow a predetermined equation in which the generated data point is a function of the amplitude of the filtered signal 46. Said data point is hereinafter referred to as the "amplitude indicator".

[0115] In another example not shown, the measuring unit comprises an analog-to-digital converter designed to convert the filtered analog signal 46 into digital data and designed to convert said digital data of the filtered signal 46 into an amplitude indicator of said filtered signal 46. In this example, said measuring unit comprises a processor or computer coupled to at least one data carrier, preferably non-transient, such as a memory, and on which is encoded an algorithm or a sequence of instructions executable by the processor to perform said conversion of the digital data into an amplitude indicator by the processor. The measuring unit is then designed so that the processor receives said digital data.In one embodiment, said unit of measurement comprises an integrated circuit such as a field-programmable gate array (FPGA) or a specialized integrated circuit such as an application-specific integrated circuit (ASIC) for generating and / or storing said digital data. Unit of calculation

[0116] In one embodiment, the electronic device 1 further comprises a computing unit 6, one embodiment of which is illustrated in [Fig. 5]. The computing unit is configured to receive at least one amplitude indicator 51 generated by the unit of measurement 5.

[0117] Preferably, the computing unit 6 is configured to detect, from at least one received amplitude indicator 51, the presence of an object 103. For example, when the amplitude indicator 51 is greater than a predetermined threshold value, the computing unit 6 considers that an object is present in the detection field.

[0118] Preferably, the computing unit is configured to generate, from at least one received amplitude indicator 51, a distance and / or position data for the object 103, relative to a reference frame. The reference frame may be a point of said electronic device fixed relative to the at least one photodetector.

[0119] Many variations are known to those skilled in the art for determining the presence, distance, and / or position of an object relative to a device based on the amplitude of the signal detected by a photodetector. For example, documents WO2023 / 175162 or EP2843509 describe means for measuring a distance between an object and a detection device. In another example, the distance of an object from the device may be proportional to the decrease in detected light amplitude or follow another rule derived from prior calibration.

[0120] The position of an object may include coordinates along at least two, preferably three, spatial directions relative to a fixed reference frame of the electronic device, for example, relative to a predetermined point on the detection surface. In one embodiment, the position data further includes shape and / or dimension information about the object in question. For example, the position data includes a point cloud or a depth map of the object detected within the detection field of the electronic device. In one embodiment, the position data may further include pose information about the object, such as the position of the fingers of a hand.

[0121] In an embodiment illustrated in [Fig. 5], the processing unit comprises a processor or a group of processors configured to receive the amplitude indicators generated by one or more photodetectors and connected to one or more memories on which is stored an algorithm or a sequence of instructions enabling the processor or group of processors to generate the presence detection, distance data, and / or position. Parallel systems

[0122] In an embodiment described above, the electronic device comprises a single photodetector.

[0123] In another embodiment represented by [Fig. 9] or [Fig. 10], the device comprises at least two photodetectors or a plurality of photodetectors for detecting luminosity comprising at least in part a component corresponding to the light intensity emitted by the photoemitter and reflected by the object.

[0124] In an embodiment illustrated in [Fig. 9], the device comprises a plurality of parallel circuits where each photodetector is connected in parallel to a circuit comprising the processing unit and the measuring unit. In this embodiment, the processing unit 6 is connected to each circuit to receive the amplitude indicator 51 from each photodetector.

[0125] In an alternative embodiment illustrated in [Fig. 10], the electronic device comprises a plurality of photodetectors, each connected to a different processing unit in parallel, and each processing unit is connected to a single measuring unit 5. Preferably, the measuring unit allows for the generation of an amplitude indicator associated with each photodetector, for example by multiplexing. One advantage is a reduction in the number of components in the electronic device.

[0126] In another preferred embodiment illustrated in [Fig. 1 1], the electronic device comprises a plurality of photodetectors 2. The photodetectors are connected to a single processing unit 4, itself connected to a measuring unit 5. The processing unit 4 is thus configured to process the detection signal from each photodetector.

[0127] Preferably, the device comprises a multiplexer 401 having a plurality of inputs and an output connected to the processing unit. Each photodetector 2 is connected to a different input of the multiplexer 401. The multiplexer allows the detection signal 41 from one photodetector 2 to pass to the processing unit 4, either one by one or one after the other. An advantage is that a single assembly comprising a processing unit 4, a measuring unit 5, and a processing unit can take into account all the photodetectors. In an alternative embodiment not shown, each photodetector 2 is designed to receive an activation signal. The activation signal for each photodetector is generated by a controller so as to activate each photodetector one after the other. Each detector 2 is designed to generate a detection signal 41 only upon receiving the activation signal.By activating the photodetectors 2 one after the other, the processing unit 4 receives the signal from a single photodetector one after the other.

[0128] In another alternative or cumulative embodiment, the device 1 comprises a plurality of photoemitters 110 that can be activated by the control signal 31 in a dependent or independent manner. Object detection method.

[0129] The method according to one embodiment is now described with reference in particular to [Fig.6] and [Fig.3].

[0130] The method includes a COM generation of the control signal 31 by the controller. The control signal is generated so that the phototransmitter emits a light signal 111 periodically. For example, the emitted light signal is a square wave signal switching from the "off" state to the "on" state at a predetermined frequency. In another embodiment, the emitted light signal can be a sinusoidal signal and / or a signal varying between two non-zero intensities periodically at a predetermined frequency.

[0131] The light signal 111 emitted by the photoemitter 110 is reflected by an object 103 located within the detection field of the electronic device 1 and reaches the photodetector 2. In this case, light rays 113 from the environment, emitted for example by a stray light source 104, also reach the photodetector. The stray light source 104 can be an ambient light source such as sunlight, light from a screen, or any other light source that is not to be measured and that would be detected by the photodetector. The invention is particularly advantageous when the intensity of the light rays 113 from the environment is significantly greater than the intensity of the reflected light rays 111 112.

[0132] The photodetector 2 detects DET a light intensity corresponding to the light rays 111 and 113 and produces in response a detection signal 4L

[0133] The detection signal is at least FIL filtered so as to retain the signal whose frequency is the predetermined frequency of the light emitted by the photoemitter 110.

[0134] The advantage is to recover a filtered signal 46 comprising the component from the photoemitter reflected by the object without the component emitted by the parasitic source 104.

[0135] Once the filtered signal is generated, the method includes the MES measurement of the amplitude of said filtered signal 46. It should be noted that the term "filtered signal" is used for any signal derived from the filtered signal 46, but which may, after filtering, have been amplified, refiltered, recentered, inverted, phase-shifted, or undergone other signal processing. For example, the filtered signal may be centered around a non-zero value greater than its amplitude, for example IV. This advantageously ensures that the signal voltage is consistently positive. The MES measurement generates an amplitude indicator 51. The amplitude indicator is preferably a function of the amplitude of the filtered signal 46. For example, the amplitude indicator may be a value representing the average amplitude of the filtered signal or the amplitude of the filtered signal after a predefined amplification operation.The functional relationship between the amplitude of the filtered signal and the amplitude indicator may depend on the components used to amplify, refilter or convert the filtered signal 46.

[0136] Preferably, the MES measurement step includes a first substep of converting the filtered signal 46 into a constant converted signal 54. The converted signal must be constant at least for the duration of the signal amplitude measurement.

[0137] In one execution mode, the converted signal 54 is generated according to a synchronization signal 33. The synchronization signal can be generated according to the phase start time of the control signal on the one hand, and a predetermined phase shift value on the other. The phase shift value is predetermined according to the phase shift induced by the various components (phototransmitter, photodetector, processing unit) on the filtered signal 46 with respect to the control signal 31, in particular according to the frequency used for the control signal 31.

[0138] The MES measurement step may include a second signal measurement substep, which is performed, for example, by an analog-to-digital converter. The digital value is preferably recorded on a memory or other data storage medium. The digital value is preferably transmitted to the processing unit 6.

[0139] Preferably, the converted signal must be constant for at least two transmission periods according to the predetermined frequency to allow its measurement or for at least two periods of the filtered signal 46 and / or at least two periods according to the frequency corresponding to the upper or lower limit of the predetermined filtering frequency range of the processing unit.

[0140] In one execution mode, the converted signal 54 can be amplified and / or filtered before the second measurement substep, for example by a separator amplifier 541 to advantageously ensure the integrity of the converted signal 54.

[0141] Once the amplitude index measurement has been carried out, the method includes the EMM calculation of the presence of an object.

[0142] Preferably, the detection of the presence of an object is determined by comparing the amplitude indicator to a predetermined threshold value.

[0143] In one embodiment, the method includes the EMM calculation of a distance and / or position data of said object from said amplitude indicator.

[0144] The calculation is preferably carried out by the calculation unit 6. The distance data may include the distance between the object and a fixed point of the detection device such as the distance with the detection surface or the distance with a photodetector.

[0145] In one embodiment, the predetermined carrier frequency of the emitted signal 111 is about 50 kHz but other frequencies may be considered.

[0146] The predetermined carrier frequency can also depend on the number of photodetectors 2 of the electronic device 1 and the frequency at which one wishes to generate a presence detection, or the generation of a distance and / or position data of the object.

[0147] For example, if 5 periods are needed to perform the amplitude measurement Given that we have 200 photodetectors and want to generate 100 distance data per second, a carrier frequency of at least 100 kHz is required. Software resources

[0148] The device according to the invention also includes software and / or hardware means for implementing the method(s) according to the invention described below. These hardware means may include computing units, processors, and memory, and are described in more detail in this description.

[0149] When it is mentioned that a processor is used, this terminology also includes cases where the device includes several processors, each configured to perform a portion of the method and which may all be integrated into a single system or at least a part of which are remote and connected to each other by wireless connections such as Bluetooth, Wi-Fi, via a remote network or any other remote communication method.

[0150] The invention thus advantageously allows the position or distance of an object to be measured precisely from a detection surface by reducing the negative impact of surrounding light on the measurement.

Claims

Demands

1. A method (10) for detecting an object comprising the following steps: • The generation (COM) of a control signal (31) to produce the emission of a light signal (111) by a phototransmitter (110); characterized in that said generated light signal (111) is a periodic signal at a predetermined frequency; • a detection (DET) by a photodetector (2) of a light comprising at least one reflected signal (112), said reflected signal comprising a portion of the light signal (111) emitted by the phototransmitter (110) which is reflected on an object (103) and arrives at the photodetector (2) and the production of a detection signal (41); • the filtering (FIL) of said detection signal (41) so as to retain, from the produced detection signal (41), only the frequencies within a predetermined frequency range to generate a filtered signal (46);said predetermined frequency being included in said predetermined frequency range; • a measurement (MES) of the amplitude of the filtered signal (46) to generate an amplitude indicator (51) of said filtered signal (46); • the detection (EMM) of the presence of an object (103) from said amplitude indicator (51).

2. Method according to claim 1, characterized in that the light detected by the photodetector (2) further comprises an ambient light (113).

3. Method according to claim 2 wherein the intensity of said surrounding light (113) captured by the detector (102) is significantly greater than the intensity of the reflected signal (112) captured by the detector (102).

4. Method according to claim 1, characterized in that the measurement step further comprises a substep of converting the filtered signal (46) into a constant converted signal (54).

5. Method according to claim 4, characterized in that the converted signal (54) is generated so as to be constant for at least the time of the measurement of the signal amplitude.

6. Method according to any one of claims 4 or 5, characterized in that the conversion of the filtered signal (46) into a constant signal (54) is carried out synchronously with the control signal (31).

7. Method according to claim 4, characterized in that the conversion of the filtered signal (46) into a constant signal is carried out by a sampler-blocker circuit (521).

8. Method according to any one of the preceding claims, characterized in that the step of detecting the presence of an object (103) includes the calculation of a distance and / or position data of said object (103) from at least one amplitude indicator (51).

9. An electronic object detection device (103) for implementing the method according to any one of claims 1 to 8 and comprising: • a controller (3) adapted to produce a control signal (31), having a predetermined periodic frequency, and intended to be used to drive a phototransmitter (110) to cause the phototransmitter (110) to emit a periodic light signal (111) having a predetermined periodic frequency; • a photodetector (2) designed to produce a light detection signal (41) comprising at least one reflected signal (112), said reflected signal comprising a portion of the light emitted by the phototransmitter (110) which is reflected off an object (103) and arrives at the photodetector (2);• a signal processing unit (4) adapted to perform the filtering of said detection signal (41) so as to retain, from the detection signal (41), only the frequencies within a predetermined frequency range to generate a filtered signal (46); said predetermined periodic frequency of the control signal being included in said predetermined frequency range; • a measurement unit (5) of the amplitude of the filtered signal (46) to generate an amplitude indicator (51) of said filtered signal (46); • a computing unit (6) configured to detect from said amplitude indicator (51) the presence of an object (103).

10. Device according to claim 9, characterized in that the signal processing unit (4) includes a high-pass filter to perform the signal filtering step, said high-pass filter being designed so that the frequency range between its cutoff frequencies includes the predetermined frequency of said light signal (111) emitted by the phototransmitter (110).

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