RU2750681C1 - Optical sensor device for determining range, speed and identification of shape and structure of object - Google Patents

Abstract

FIELD: optical sensor device.SUBSTANCE: invention relates to an optical sensor device for determining the distance to an object and the speed of an object and for recognizing the shape and structure of an object and a method for determining the distance to an object and the speed of an object and for recognizing the shape and structure of an object. The sensor device contains optically coupled at least one source of laser radiation, at least one optical collimating means, beam splitting means, reflective means, optical means for directing the beam and at least one detector for recording radiation reflected from the object, as well as a controller, when each of the at least one source of laser radiation with the corresponding at least one detector form at least one individually functioning and individually adjustable measuring channel with the possibility of providing characteristic data about the object, the controller is configured to ensure the simultaneous or selective operation of the said measuring channels and the operational regulation of the radiation parameters of at least one laser radiation source, depending on the required spatial resolution of the object position during the operation of the device, and processing and analysis of the characteristic data of the object recorded on at least one detector for simultaneously determining the distance to the object and its speed, and recognizing the shape and structure of the object.EFFECT: invention is aimed at ensuring the operation of the sensor device at short distances (1-10 m), determining the distance to stationary and moving objects, determining the speed, shape and structure of the object. Also, improving the reliability of functioning and manufacturability of the lidar, as well as reducing the influence of external noise.22 cl, 26 dwg, 1 tbl

Description

The technical field to which the invention relates

The invention relates to a compact optical sensor device for determining the range, speed and identification of the shape and structure of an object, for example, a solid-state lidar, a method for determining the range, speed of identifying the shape and structure of an object using said optical sensor device, and can be used in various fields of technology. The optical sensor device, according to the invention, is configured to determine the distance to the object, the speed of the object, as well as the structure of the object and the structure or material from which the object is made and can be used in sensors for navigation purposes used for mobile electronic devices, compact portable devices, such as for household purposes, for example, vacuum cleaners, and in other household appliances to expand their functions, in particular as a gesture sensor, and for industrial purposes for navigating an object and contactless identification of object parameters, for example, the structure and material (composition) of an object.

Description of the prior art

Range determination devices or lidars (LIDAR), which literally stand for light identification, detection and ranging systems, were originally intended for military purposes and were aimed at tracking targets (objects) over long distances of tens of kilometers. But with the growing popularity of portable electronic devices, the demand for compact lidars for identifying objects over short distances (several meters) in enclosed spaces, and used in compact robotics, such as compact household vacuum cleaners, has grown.

Lidars known in the prior art work according to the following principle:

a device in the form of an IR LED or a laser sends out directed radiation, then, with the help of a light-sensitive receiver (sensor), it receives reflected waves and builds a picture of space based on this.

Having received the time during which the reflected wave returned, we can determine the distance to the object in the sensor's field of view, for example, using the formula:

D is the measured distance ; c is the speed of light in the optical medium ; f is the frequency of scanning pulses ; Δφ is the phase shift . This principle of determining the distance is called Time-of-flight (ToF).

A compact lidar system is known from the prior art, see US 10,215,846 B2, publ. 02/26/2019; IPC G01S 17/02, operating according to the time-of-flight principle described above. The lidar system includes a static monolithic transceiver 202, collimating optics, first and second rotatable wedge prisms 206, 208. By rotating wedge prism 206 relative to wedge prism 208, the collimated laser beam can be controlled by refraction of the collimated laser beam as it passes through wedge prisms 206 and 208. The static monolithic transceiver 202 is configured to emit a laser beam and receive reflected laser light from a first target. In this lidar system, the emitter and the detector are combined on a single transceiver chip 202. In this case, this system has the following disadvantages: mechanical motors 210, 212 are required to rotate the wedge-shaped prisms 206, 208, which is accompanied by a significant device size, which makes it impossible to use the lidar in compact electronic devices. In addition, traditionally a time-of-flight solution requires high-speed electronics to measure the time of flight in ns, which significantly complicates and increases the cost of manufacturing the lidar system. In this case, the specified lidar system provides information only about the distance to the object. And the specified lidar system is characterized by illumination from other sources and noise from interference from other possible lidars located in the area of operation of the lidar system, which significantly reduces the accuracy of obtaining data on the distance to the object.

A compact laser scanner based on a vertical cavity surface-emitting laser (VCSEL) array is disclosed in US 7,544,945 B2, publ. 09.06.2009 IPC G01J 5/02 and also applies to time-of-flight solution. This system 100 is used in automotive lidars and contains an array 110 of a plurality of semiconductor lasers 120; an optical element 130 positioned relative to the plurality of lasers such that at least two of the plurality of lasers produce beams that exit the optical element in substantially different directions; and a control circuit associated with the plurality of semiconductor lasers and configured to sequentially and separately activate at least two of the plurality of lasers. By sequentially activating each semiconductor laser separately, the system 100 can be used to scan the laser beam into the field of view of the lens 130. One or more photodetectors can be located near the laser array 110 to collect light from the activated laser that is reflected by objects illuminated by the laser beam. Angular information, such as the direction of a detected object, is determined by knowing which semiconductor laser in the array has been activated. Lenses can also be integrated or linked to photodetectors to improve detection efficiency and increase the detected signal level. System 100 operates in a way that can replace lidar laser systems that use mechanical drives to rotate or move reflective optics. In this case, lasers 120 and photodetectors are located on a single chip. It should be noted that this system based on the time-of-flight principle has all the disadvantages inherent in the solution disclosed in US 10,215,846 B2: high-speed electronics is needed to measure the time of flight in ns, which greatly complicates and increases the cost of manufacturing the lidar system; the specified lidar system provides information only about the distance to the object. And the specified lidar system is characterized by illumination from other sources and noise from interference from other possible lidars located in the area of operation of the lidar system, which significantly reduces the accuracy of obtaining data on the distance to the object.

A laser radar is known from the prior art, see publication WO 2018/133084 A1, publ. 26.07.2018. IPC G01S 17/08, which is an array of surface-emitting lasers 150 with a vertical cavity (VCSEL) on a first substrate (110) and an array of detectors (143) on a second substrate (120), with the detectors and lasers on the same chip. In this case, the detectors (143) are configured to detect laser beams emitted by the VCSEL (150) and backscattered by an object, the first substrate (110) being attached to the second substrate (120) and configured to provide the passage of the laser beams emitted by the VCSEL (150 ) and backscattered from the object through the first substrate (110) and reach the detectors (143).

It should be noted that this radar, based on the time-of-flight principle, has all the drawbacks inherent in such solutions: high-speed electronics is needed to measure the time of flight in ns, which significantly complicates and increases the cost of the radar manufacturing; the specified laser radar provides information only about the distance to the object. And the specified radar is characterized by illumination from other sources and noise from interference from other similar devices located in the area of operation of the laser radar system, which significantly reduces the accuracy of obtaining data on the distance to the object.

The closest analogue of the claimed invention is a solution based on the principle of homodyne interference (self-mixing interference) and disclosed in US 8,692.979 B2, publ. 04/08/2014, IPC G01C 3/00, which contains a sensor module (1) for measuring the distance to the target and / or target speed (50), and the sensor module (1) contains at least one laser source (100 ), for example a vertical cavity surface emitting laser (VCSEL), at least one detector (200), a VCSEL laser and a detector are integrated in one device, and at least one control element (400). A detector (200) can detect modulation of resonant laser radiation in the laser source (100). Modulation of laser light in a laser source can be induced by laser light reflected from a target re-entering the laser source. The effect is known to those skilled in the art as self-mixing. Depending on the scheme of the electric drive of the laser source, the distance and / or speed of the target can be determined. The laser sensor is based on the principle of frequency modulated continuous wave (FMCW). In this design, there are no problems inherent in time-of-flight solutions, i.e. the possibility of exposure from other radiation sources and interference from other functioning similar devices. However, the emitting region of VCSEL lasers is quite small and amounts to 10-15 microns, which in turn causes a rather low signal-to-noise ratio of the laser sensor. The specified laser sensor provides only the receipt of the distance to the target.

Thus, to eliminate all the above disadvantages of prior art lidars, the authors have created a compact optical sensor device for determining the range, speed and identification of the shape and structure of an object and a method for determining the range, speed and identification of the shape and structure of an object using this device.

As already mentioned above, the object of the claimed invention is to create a sensor device operating at short distances, in particular 1-10 m, safe for the user's eyes, providing, in addition to obtaining the distance of both a stationary and a moving object, and the speed of the object, also the shape of the object. and its structure, i.e. the type of material from which the investigated object is made. In addition, if conventional ranging devices, i. E. lidars are provided with mechanical motors to ensure the rotation of the platform on which the means are installed that ensure the scanning of the object (rotary prisms, etc.) in the claimed sensor device there are no moving mechanical parts, which increases the reliability and manufacturability of the lidar. In addition, since the claimed sensor device uses coherent reception (i.e., such a reception in which only the signal coherent to the local oscillator receives significant amplification), any other (incoherent to the local oscillator) signals will not be amplified and will be invisible against the background noise. Thus, any such means working nearby will not interfere and the possibility of exposure of the claimed sensor device to other sources of radiation, for example, the sun or external artificial lighting, in particular street lamps, is excluded. The claimed sensor device is made with the ability to quickly reconfigure the operating parameters, due to the regulation of the current supplied to the laser radiation sources, has a low weight (from several tens of grams), which allows it to be embedded in mobile electronic devices.

The essence of the invention

According to a first aspect of the invention, there is provided an optical sensor device for determining the distance to an object, the speed of the object, and for identifying the shape and structure of the object, comprising:

optically coupled at least one source of laser radiation, at least one optical collimating means located above the corresponding at least one source of laser radiation, beam-splitting means, reflective means, optical means for directing a beam, configured to direct the beam in a predetermined direction to object, and at least one detector for recording radiation reflected from the object, as well as a controller connected to each of at least one detector and at least one source of laser radiation,

wherein each of the at least one laser radiation source with the corresponding at least one detector form at least one individually functioning and individually adjustable measuring channel with the possibility of providing data on the distance to the object,

in this case, the controller is configured to ensure the simultaneous or selective functioning of the said measuring channels and the operational regulation of the radiation parameters of at least one source of laser radiation, depending on the required operational resolution in the range during the operation of the device, and processing and analysis of the object data recorded on at least at least one detector to simultaneously determine the distance to the object and its speed, and recognize the shape and structure of the object.

In said sensor device, at least one laser source is a wavelength tunable laser, such as a vertical cavity surface emitting laser (VCSEL) with a wavelength of 700 to 950 nm.

In this case, at least one laser radiation source may contain several laser radiation sources forming a two-dimensional matrix of laser radiation sources, and at least one detector is a matrix photodetector or

at least one detector comprises a plurality of detectors forming a two-dimensional array of detectors.

It should be noted that in the sensor device at least one optical collimating means is at least one microlens, and is configured to collimate radiation emitted by at least one laser radiation source, or at least one microlens is a set of microlenses forming a two-dimensional matrix microlenses.

In addition, the beam-splitting means is a beam-splitting cube with a semi-reflecting mirror located inside the specified cube and made with the possibility of dividing the beam into reference and measuring beams, and the light-reflecting means is a light-reflecting coated, applied to the inner or outer surface of the beam-splitting cube and made with the possibility of re-reflection of the reference beam to the corresponding detector or the light reflecting means is a mirror located in front of the outer surface of the beam splitting cube, and made with the possibility of re-reflection of the reference beam to the corresponding at least one detector.

It should also be noted that in the sensor device, the optical means for guiding the beam is a lens having a flat surface on the side facing the beam splitting cube, and on the side facing the object has a surface consisting of at least one microlens, each of which is at least one microlens corresponds to at least one laser source.

In addition, each of the at least one microlens is located at a predetermined angle to the corresponding incident laser beam and is designed so that the corresponding laser beam, after passing through the microlens, is directed in the desired predetermined direction towards the object.

The optical means for directing the beam can be made in the form of a two-dimensional array of microlenses, with each microlens from the array of microlenses located at a predetermined angle to the corresponding incident laser beam and made in such a way that the corresponding laser beam, after passing through the microlens, is directed in the required predetermined direction to the object ...

In the sensor device according to the invention, there is also provided at least one driver connected to the corresponding at least one laser radiation source and providing pumping current to it according to the control signal of the controller.

In addition, an optical isolator is also provided in the sensor device, located between the beam splitting means and at least one optical collimating means, and configured to prevent the reflected light from the target object from hitting at least one laser radiation source and preventing destabilization of the functioning of said sources.

One of the advantages of the claimed sensor device according to the first aspect of the invention is its multimodality. The sensor device can function as a gesture sensor by providing operational control of the radiation parameters of at least one laser radiation source, as well as adjusting the range and field of view resolution. In this case, the regulation of the radiation parameters is provided by changing the parameters of the pumping current supplied to the specified at least one source of laser radiation, and the parameters of the pumping current include the frequency and amplitude of the modulation of the current supplied to the specified at least one radiation source.

And regulation of the range resolution is provided by simultaneously changing the number of functioning laser radiation sources and changing the amplitude of the pump current modulation supplied to the indicated laser radiation sources.

In this case, the regulation of the field of view is provided by changing the number of interrogated detectors.

The sensor device can function as a three-dimensional scanner by providing alternating operation of the said laser sources, operatively adjusting the radiation parameters of at least one laser radiation source, and adjusting the range and field of view resolution.

In this case, the regulation of the radiation parameters is provided by changing the parameters of the pump current supplied to the specified at least one source of laser radiation, while

the parameters of the pump current include the frequency and amplitude of the modulation of the current supplied to the specified at least one radiation source.

In addition, the control of the range resolution is provided by changing the number of simultaneously operating laser sources and changing the amplitude of the pump current modulation supplied to the said laser sources, the control of the field of view is provided by changing the number of interrogated detectors.

According to a second aspect of the invention, there is provided a method for determining the distance to an object, the speed of the object and for recognizing the shape and structure of the object by means of an optical sensor device according to the first aspect of the invention, the method comprising the steps of:

- emitting laser radiation with a predetermined wavelength from 700 to 950 nm using at least one source of laser radiation, while operatively adjusting the pump current supplied to at least one source of laser radiation, depending on the required resolution of the object during operation devices, while regulating the pump current from 3 to 6 mA.

- direct the specified radiation to the beam splitter,

where part of the radiation, which is the reference beam, is redirected to at least one detector,

and the other part of the radiation, representing the measuring beam, is directed to the optical means for guiding the beam, ensuring the deflection of the specified measuring beam in a predetermined direction towards the object,

further, the at least one measuring beam reflected from the object is directed to the corresponding at least one detector, on which the frequency difference of the signals generated by the measuring and reference beams is measured, on the basis of which, at the same time, the distance L to the object and the speed V of the object are determined,

in this case, as the measuring beam passes through the object and / or is reflected from it, registration of the distribution of the reflection coefficient of at least one measuring beam reflected from the object depending on the distance to the object is provided, on the basis of which the shape and structure of the object is identified.

In this case, the distance L (m) to the object is determined by the ratio:

,

,

where c is the speed of light (m / s), α is the rate of rise of the radiation frequency (Hz / s),

Δω ₁ is the frequency difference of the signals formed by the measuring and reference beams with increasing radiation frequency (Hz),

and Δω ₂ is the frequency difference of the signals generated by the measuring and reference beams at a decrease in the radiation frequency (Hz).

In addition, the speed V (m / s) of the object is determined by the ratio:

,

,

where c is the speed of light (m / s), α is the rate of rise of the radiation frequency (Hz / s), ω _{0 is the} frequency of the emitted light (Hz)

Δω ₁ is the frequency difference of the signals formed by the measuring and reference beams with increasing radiation frequency (Hz), and

Δω ₂ is the frequency difference of the signals generated by the measuring and reference beams at a decrease in the radiation frequency (Hz).

And at the stage of regulating the pump current supplied to at least one source of laser radiation, an operational change in the resolution (Res) of the object in terms of range is provided, determined by the following relationship:

Res

c- speed of light (m / s)

Ώ-dependence of the frequency of the emitted laser light depending on the current pumped into at least one source (1 ₁ ... 1 _n ) of laser radiation (Hz / mA),

dI is the amplitude of the modulation of the current of the laser radiation source during the scanning of the object (mA).

In addition, in the method according to the invention, the step of identifying the shape and structure of the object is carried out in the controller by comparing the obtained pattern of the distribution of the reflection coefficient of at least one measuring beam reflected from the object with the known patterns of the distribution of the reflection coefficients characteristic of certain structures of objects stored in the memory of the controller. ...

Brief Description of Drawings

The above and other features and advantages of the present invention are illustrated in the following description, illustrated by the drawings, in which the following is presented:

Fig. 1 illustrates a schematic diagram of a heterodyne measurement method known in the art;

Fig. 2a illustrates a diagram of an optical sensor device for determining the range, velocity and identification of the shape and structure of objects according to the first embodiment of the invention;

FIG. 2b illustrates a diagram of an optical sensor device for determining the range, velocity and identification of the shape and structure of objects with a dedicated channel formed by a pair: a laser radiation source and a detector, according to the first embodiment of the invention;

Fig. 2c illustrates a diagram of an optical sensor device for determining the range, velocity and identification of the shape and structure of objects according to a second embodiment of the invention;

Fig. 2d illustrates a diagram of an optical sensor device for determining the range, velocity and identification of the shape and structure of objects according to a third embodiment of the invention;

Fig. 2e illustrates a diagram of an optical sensor device for determining the range, velocity and identification of the shape and structure of objects according to a fourth embodiment of the invention;

Fig. 2f illustrates a diagram of an optical sensor device for determining the range, velocity and identification of the shape and structure of objects according to a fifth embodiment of the invention;

Fig. 3a illustrates an example of an image generated during scanning by conventional known ranging devices (lidars) based on the time-of-flight principle of determining the distance to an object;

FIG. 3b illustrates an example of an image formed by an optical sensor device for determining the range, velocity and identification of the shape and structure of objects according to the invention;

FIG. 4a is a graph illustrating the dependence of the pump current of the laser source on time for medium range resolution;

FIG. 4b is a graph illustrating the pump current of the laser source versus time for high range resolution;

FIG. 5a is a graph illustrating the dependence of the pump current of the laser source on time for an average of the frame rate;

FIG. 5b is a graph showing the pump current of the laser source versus time for a high frame rate;

FIG. 6a shows an example of the arrangement of transparent and opaque objects (two thin glass plates as an example of transparent objects and a concrete wall as an example of an opaque object) along the path of the laser beam;

FIG. 6b is a diagram of the distribution of the reflection coefficient along the path of the laser beam, corresponding to the example of the arrangement of transparent and opaque objects according to FIG. 6a;

FIG. 7a shows an example of the location of a fabric object;

FIG. 7b is a view of a fabric structure with a denser "layer" inside according to FIG. 7a;

Fig. 7c is a diagram of the distribution of the reflection coefficient along the path of the laser beam, corresponding to the example of the location of the object, which is a tissue according to Figs. 7a and 7b;

FIG. 8 is a schematic view of a beam guiding optical means (6) in the form of a lens according to the invention;

Fig. 9a is a graph illustrating a signal obtained using a plastic plate as an object;

Fig. 9b is a graph illustrating a signal obtained using human palm skin as an object;

Fig. 9c is a graph illustrating a signal obtained when using a protective mask fabric as an object;

Fig. 9d is a graph illustrating a signal obtained using a glass plate as an object;

Fig. 10 shows a navigation map generated by a computer based on data received from the controller (9) when identifying objects in the research laboratory;

Fig. 11 is an enlarged view of the details of images of objects from Fig. 10;

Fig. 12 schematically shows a setup for experimental research on the accuracy of measuring the speed of a moving object using the claimed sensor device;

Table 1 shows the results of the obtained studies of the parameters of the claimed sensor device and similar devices known from the prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

The present invention is intended to provide an optical sensing device for ranging, velocity and shape and structure identification of an object. The principle of operation of the claimed optical sensor device for determining the range, velocity and identification of the shape and structure of an object according to the invention is based on a heterodyne measurement method well known in the art (see, for example, Jacobs, Stephen (30 November 1962). Technical Note on Heterodyne Detection in Optical Communications (PDF) (Report) Syosset, New York: Technical Research Group, Inc.), and is based on the comparison of the frequency of the light signal under investigation with the frequency of the signal of a local oscillator-laser. Figure 1 shows a general diagram of a heterodyne measurement method, a light signal representing a generated electric field, described as (E ₁ cos (ω ₁ t)), and oscillating at a very high frequency, which is reflected from the object and the signal from the local oscillator or a local oscillator (laser), which is an electric field described as (E ₂ cos (ω ₂ t)), with a very high frequency using a beam splitter, are converged on a photodiode, where the photocurrent is measured. The photodiode serves as an ideal square law detector because it measures optical power, which is proportional to the square of the electric field. In this case, if the frequencies of the light signal and the signal from the oscillator differ slightly (on the order of kHz or MHz), the photodiode will determine this difference frequency.

In this case, the current (I) passing through the photodiode is proportional to the square of the resulting electric field:

(one)

Where

I is the resulting current of the photodiode caused by the simultaneous incidence of the local and measuring beams on it,

E ₁ is the electric field strength for the light signal,

E ₂ is the electric field strength for a local oscillator,

ω _{1 is the} frequency of the electric field for the light signal

ω ₂ is the frequency of the electric field for the signal of the local oscillator

t-time.

After a series of transformations, we obtain the following relation (2) characterizing the current (I) passing through the photodiode:

(2)

The current (I) passing through the photodiode is determined by two components: the first component (left square bracket) is the sum of the powers of the light signal and the oscillator signal and the signal oscillating at the difference frequency (equal to the difference between the two frequencies, namely the frequencies of the light signal and the oscillator signal) , and the second component (right square bracket) represents signals that oscillate at very high frequencies (above optical) and, therefore, are not detected by the photodiode. The left component is the following ratio:

(3)

+

отфильтровывается с использованием фильтра верхних частот, а компонента E₁E₂ cos(Δωt) характеризует гетеродинный сигнал, характеризующий разность частот, который и детектируется на фотодетекторе.Where is the component

+

is filtered using a high-pass filter, and the component E ₁ E ₂ cos (Δωt) characterizes the heterodyne signal characterizing the frequency difference, which is detected on the photodetector.

By varying the frequency of the laser linearly with time (i.e., the frequency of the electromagnetic field emitted by the laser), it is possible to obtain a linear dependence of the difference between the two frequencies Δω (namely, the frequencies of the light signal and the oscillator signal) (Hz) on the distance to the object that reflected the light signal.

(four)

, where L is the distance to the object (m), s is the speed of light (m / s), α is the frequency of laser radiation frequency tuning (Hz / s)

Thus, the distance to the object and the frequency of the local oscillator signal are linearly related and, having determined the frequency of the local oscillator signal, we can calculate the distance to the object that reflected the light signal:

(five)

Thus, the current through the photodiode will be the sum of harmonic signals, and for each harmonic signal, the frequency of this signal will determine the distance to the object reflecting light, and the amplitude of this harmonic signal will determine the reflectance of this object. For the spectral analysis of the photodiode current (i.e., to determine the frequencies and amplitudes of its constituent harmonic signals), the fast Fourier transform method can be applied

The following are preferred embodiments and Examples of the optical sensor device with reference to FIGS. 2a and 2b, 2c, 2d and 2f.

FIG. 2a shows a diagram of an optical sensor device for determining the range, speed and identification of the shape and structure of objects (hereinafter, as a sensor device), containing at least one source (1 ₁ ... 1 _n ) of laser radiation (hereinafter as a laser), in particular a surface emitting laser with a vertical resonator (VCSEL), operating in the wavelength range of about 700-950nm, made with the possibility of operational control of the radiation parameters by means of the corresponding at least one driver (2 ₁ ... 2 _n ) by a signal from the main controller 9. In this case, for each of at least one source (1 ₁ ... 1 _n ) of laser radiation is provided with a corresponding at least one collimating optics (3 ₁ ... 3 _n ), for example, in the form of at least one collimating microlens located above the sources (1 ₁ ... 1 _n ) laser radiation, beamsplitting means 4, for example beamsplitting cube 4 with a semi-reflecting mirror (not shown) located inside the specified th cube, and made with the possibility of dividing the beam into reference and measuring beams. In addition, the beam-splitting cube 4 contains a reflective means 5, made in the form of a light-reflecting surface located on the outer or inner surface of the side face of the beam-splitting cube 4 or in the form of a mirror 5 (see Fig. 2c) located in front of the side face of the beam-splitting cube 4. Sensor device also contains an optical means 6 for directing a beam, configured to direct at least one collimated beam of radiation in a predetermined direction, while simultaneously operating several sources (1 ₁ ... 1 _n ) of laser radiation, the optical means 6 for directing a beam deflects each of the emitted laser beams in a predetermined direction, while the optical means (6) for directing the beam is a lens having a flat surface on the side facing the beam splitting cube 4, and on the side facing the object has a surface consisting of at least one microlens, with wherein each of the at least one microlens corresponds to at least one source of laser radiation. In this case, each of the at least one microlens is located at a predetermined angle to the corresponding incident laser beam and is made in such a way that the corresponding laser beam, after passing through the microlens, is directed in the desired predetermined direction.

Figure 8 shows an example of optical means (6) for directing the beam in the form of a lens with a field of view of 17 × 17 degrees and the number of optical microlenses or lens microelements 25 (5 × 5), each responsible for directing one laser beam to a given point of the object or optical the means for guiding the beam can be made in the form of at least one microlens (6 ₁ ... 6 _n ) (see Fig. 2d).

In this case, the sensor device also includes at least one detector (7 ₁ ... 7 _n ), configured to detect the emitted laser radiation and connected via at least one converter (8 ₁ ... 8 _n ) with the main controller 9, which includes a processor data. In this case, according to figure 2a as one embodiment, the sources (1 ₁ ... 1 _n ) of laser radiation form a two-dimensional matrix of emitters, collimating optics (3 ₁ ... 3 _n ) forms a two-dimensional matrix of microlenses, and detectors (7 ₁ ... 7 _n ) form a two-dimensional array of detectors.

FIG. 2b shows a diagram of an optical sensor device for determining the range, speed and identification of the shape and structure of objects according to FIG. 2a, in which one measuring channel is highlighted by a dash-dotted line, formed by a pair: one of the sources (1 ₁ ... 1 _n ) of laser radiation and one of detectors (7 ₁ ... 7 _n ). In this case, each of the sources (1 ₁ ... 1 _n ) of laser radiation with the corresponding driver from the drivers (2 ₁ ... 2 _n ) and each of the detectors from the detectors (7 ₁ ... 7 _n ) with the corresponding converter from the converters (8 ₁ ... 8 _n ), form an individually functioning and individually adjustable working channel, while all these channels can work simultaneously or selectively, depending on the control signal coming from the main controller (9).

FIG. 2c shows a diagram of the sensor device, which completely repeats the scheme of the sensor device according to FIGS. 2a and 2b, except for the location of the mirror 5 not on the side edge of the beam splitting cube 4, but placed in front of its lateral edge. In this case, the operation of the sensor device according to FIG. 2c completely repeats the operation of the device according to FIGS. 2a and 2b.

FIG. 2d shows a diagram of the sensor device, which completely repeats the scheme of the sensor device according to FIGS. 2a and 2b, except for the implementation of the optical means 6 for directing the beam, which is a matrix of microlenses (6 ₁ ... 6 _n ), each of the microlenses (6 ₁ ... 6 _n ) guides the laser beam to the target point of the object. In this case, the operation of the sensor device according to FIG. 2d completely repeats the operation of the device according to FIGS. 2a and 2b.

FIG. 2e shows a diagram of the sensor device, which completely repeats the scheme of the sensor device according to FIGS. 2a and 2b, except for the addition of an optical isolator 10 to the circuit, which is an optical element that ensures the passage of the laser beam in only one direction, namely from the laser source 1 to beam-splitting means 4, and located between the beam-splitting means 4 and at least one optical collimating means (3 ₁ ..3 _n ), and configured to prevent the reflected light from the object from entering at least one source (1 ₁ ..1 _n ), laser radiation and prevention of destabilization of the functioning of these sources. In this case, the operation of the sensor device according to FIG. 2e completely repeats the operation of the device according to FIGS. 2a and 2b.

FIG. 2f shows a diagram of the sensor device, which completely repeats the scheme of the sensor device according to FIGS. 2a and 2b, only the prism 11 is introduced into the circuit, due to which the reference and measuring beams, after leaving the beam splitting cube 4, fall on the prism 11 and are redirected after being reflected from its inner surface to the corresponding detector (7 ₁ ..7 _n ), and due to this trajectory of the beam, a more optimal arrangement of the elements of the sensor device is provided, which makes it possible to place sources (1 ₁ ..1 _n ) of laser radiation with drivers (2 ₁ ..2 _n ), and detectors (7 ₁ ..7 _n ), on one chip. This arrangement of the sensor device on a single chip allows a significant reduction in the size of the sensor device, which plays a decisive role in its use in mobile sensor devices. Fig. 2f omits part of the circuit illustrating the converters and the main controller, but it completely repeats the circuit of Figs. 2a and 2b. In this case, the operation of the sensor device according to FIG. 2f completely repeats the operation of the device according to FIGS. 2a and 2b.

It should be noted that all optical elements (laser sources, collimating means, beam splitting means, optical means for guiding the beam, detectors and other optical elements) included in the sensor device and shown in FIGS. 2a-2f are optically coupled to each other. ...

The sensor device according to the invention (see Fig. 2a-2f) operates as follows: laser radiation with a predetermined wavelength (700-950 nm) is emitted by at least one of the sources (1 ₁ ... 1 _n ) of laser radiation, passes through at least one of the collimating microlenses (3 ₁ ... 3 _n ), and falls on the beam splitting cube 4, where part of the radiation - the reference beam (indicated by the dashed line in Figs.2a-2f) is reflected from the semitransparent mirror (not shown) inside the beam splitting cube 4 and falls on the reflecting surface 5 (Fig. 2a) or the mirror 5 (see Fig. 2c) of the beam splitting cube 4, reflected from which falls on the corresponding at least one detector (7 ₁ ... 7 _n ) _, and the second part of the radiation is a measuring the beam (indicated by the solid line in Figs.2a-2f) passes through the beam-splitting cube 4 and falls on the optical means 6 of the direction of the beam, made with the possibility of directing the specified measuring beam at a given angle to the object under study, g After being reflected from it, the reflected measuring beam passes the means 6 of the direction of the beam and the beam splitting cube 4 and falls on the corresponding detector from the detectors (7 ₁ ... 7 _n ), where the frequency difference Δω is measured, from the two signals formed by the reference and the measuring beam according to the heterodyne method measurements described above.

Described in FIGS. 2a-2f, the scheme of the sensor device according to the invention ensures the operation of each pair forming the measuring channel, for example, a source (1 ₁ ) of laser radiation (emitter) and a detector (7 ₁ ) in a fixed direction towards the point of the object. Thus, the object to be examined is scanned simultaneously, and each pair: the emitter-detector is aimed at one of its specific points located on the object, the sensor device thus covers the entire field of view. In this case, each measuring channel formed by the corresponding pair-emitter and detector (see Fig. 2b, highlighted by a dash-dotted line), operates independently of other channels, but at the same time scanning the object by sources (1 ₁ ... 1 _n ) of laser radiation and detectors (7 ₁ … 7 _n ) runs simultaneously. Thanks to such a scheme of the sensor device, the distance to the object and the speed of the object (objects) are measured at the same time (t), which increases the accuracy of the obtained parameters and the high speed of the sensor device according to the invention.

Due to this, the effect of fuzziness or blurring of the image of a moving object does not occur, since the distance to the object is measured at the same moment in time, in contrast to traditional distance measuring devices (lidars), where, when scanning an object, each subsequent point of the object falling on the beam is displaced by some Δt and some distance Δs, which causes the appearance of distortions in the image of the object, which is clearly seen in Fig. 3a, which shows a slightly distorted image of an object in the form of a black cat. In this case, the same image in FIG. 3b shows a clear image as all points of the object are scanned simultaneously across the entire field of view. The high speed of operation of the described sensor device is provided due to the measurement in the entire field of view at the same time and the absence of mechanical rotating parts that limit the speed in classical lidars.

The operation of the optical sensor device for determining the range, velocity and identification of the shape and structure of objects according to the invention is based on the principle of frequency-modulated continuous radiation (FMCW), which makes it possible to adjust the length resolution and frame rate on the fly, i. E. during the operation of the sensor device, without making structural changes directly to the device itself, but only by changing the operating parameters of the sources (1 ₁ ... 1 _n ) of laser radiation, namely the current supplied to the sources (1 ₁ ... 1 _n ) of laser radiation through the drivers ( 2 ₁ … 2 _n ) by a signal from the main controller (9).

One of the parameters determined by the declared sensor device is the operational resolution (Res) in terms of range.

At the same time, the authors conducted experimental studies in which the amplitude of modulation of the pump current supplied to the sources (1 ₁ ... 1 _n ) of laser radiation in the sensor device according to the invention was 3 mA (the pump current varied from 3 mA to 6 mA), while the resolution the range was 0.25 mm, and with a current modulation amplitude of 1 mA (the pump current varied from 4 mA to 5 mA), the range resolution was 0.75 mm. In both cases, a change in the value of the current supplied to the laser radiation sources made it possible to adjust the resolution in terms of the distance to the object. In this case, the wavelength of the laser radiation sources was 850 nm.

Similar studies were carried out at a wavelength of laser radiation sources equal to 780 nm. In this case, the amplitude of modulation of the pump current supplied to the sources (1 ₁ ... 1 _n ) of laser radiation was 40 mA (the pump current was varied from 80 mA to 120 mA), while the range resolution was 6 mm, and with a modulation amplitude of the current of 10 mA (the pump current was varied from 100 mA to 110 mA) the range resolution was 25 mm. In both cases, a change in the value of the current supplied to the laser radiation sources made it possible to adjust the resolution in terms of the distance to the object.

Range resolution (Res) can be calculated as:

(6)

(6)Res

(6)

c - speed of light (m / s),

Ώ-dependence of the frequency of the emitted laser light depending on the current pumped into at least one source (1 ₁ ... 1 _n ) of laser radiation (hereinafter referred to as a laser) (Hz / mA),

dI is the amplitude of the modulation of the current of the laser radiation source during the scanning of the object (mA) (i.e., the restructuring of the laser radiation source by current during the scanning of the object.

By changing the amplitude of the modulation of the current (dI) in the process of scanning the object, it is possible to change the operative range resolution.

Graphs 4a and 4b clearly show graphs illustrating the dependence of the length resolution on the current, and in Fig. 5a and 5b are graphs illustrating the dependence of the frame rate on the pump current of the laser for cases of high and medium frame rates (i.e., the number of measurements per unit time), where in FIG. 4a shows the dependence of the pump current of the laser radiation source (laser) on time, at which the average resolution of the distance determination (about 3 mm) is realized, and in Fig. 4b dependence of the pump current of the laser radiation source (laser) on time, at which a high resolution of the distance determination is realized (about 0.25 mm). In addition, in FIG. 5a shows the average scan rate and FIG. 5b-high scanning speed. The ordinate indicates the value of the current supplied to the laser source (mA), and the abscissa indicates the time (sec). In these charts, one period corresponds to one dimension. It can be seen from these graphs that the faster the signal repeats, the higher the frame rate. The higher the signal amplitude (i.e. the swing between the minimum and maximum), the higher the accuracy in determining the distance.

Since the claimed sensor device is based on the principle of frequency-modulated continuous radiation (FMCW), in addition to determining the distance to the object, it can identify the parameters of the object itself, because The inventive sensor device is capable of outputting data on the distribution of reflection coefficients depending on the surface structure of the object.

Classical optical ranging devices (lidars) based on the time-of-flight principle as "raw", i.e. of unprocessed data, one point is returned in each direction, which corresponds to the time of flight of the light to the object, from which the light was reflected back into the lidar. In contrast to traditional time-of-flight lidars, the claimed device provides, as "raw" (unprocessed) data, information on the distribution of the reflection coefficient for each beam, depending on the distance reflected from the object.

FIG. 6a, 6b are graphs that clearly demonstrate this principle of operation.

FIG. 6a shows a diagram of the arrangement of transparent and opaque objects along the path of the beam emitted by the laser radiation source (laser), and FIG. 6b illustrates the distribution of reflectances obtained when a laser beam passes through transparent or opaque objects. As seen in FIG. 6a on the path of the laser beam there are two transparent windows (glass plates) and then there is a sufficiently extended opaque object, for example a wall.

90%) , а незначительная часть излучения (5-10%) рассеивается или отражается при прохождении через указанные прозрачные объекты. Соответственно на фиг. 6b изображены два маленьких пика, характерные для отраженного от прозрачных объектов луча и один большой пик, характерный для луча, практически полностью отраженного от стены. Как видно из графика амплитуды пиков пропорционально коэффициенту отражения светового сигнала (т.к. отражения от объектов на различном расстоянии приведет к сигналу от фотодетектора на разных частотах, которые могут быть легко различены согласно формуле (4)).The laser beam emitted from a source (1 ₁ ... .1 _n ) of laser radiation (laser) passes through two transparent windows (two thin glass plates) located along the path of the beam, which transmit most of the radiation (

90%), and an insignificant part of the radiation (5-10%) is scattered or reflected when passing through the indicated transparent objects. Accordingly, in FIG. 6b shows two small peaks characteristic of a beam reflected from transparent objects and one large peak characteristic of a beam that is almost completely reflected from a wall. As can be seen from the graph, the peak amplitudes are proportional to the reflection coefficient of the light signal (since reflections from objects at different distances will lead to a signal from the photodetector at different frequencies, which can be easily distinguished according to formula (4)).

Thus, according to the indicated graphs, it is possible to judge the type of objects located in the path of the beam propagation from the laser radiation source, i.e. two small peaks - a small reflection from a transparent object (glass) and one large peak (a large reflection from an opaque object (wall).

Further, when the signal is converted from frequency to distance, i. E. in meters, we can conclude that along the path of the beam there are two objects that reflect little light back into the sensor device (i.e. transparent objects) and behind them there is one object with a high reflection coefficient (large peak) of light from this object (i.e. wall) back to the touch device.

Thus, such a function of the sensor device according to the invention will improve the quality of navigation within the space of a house or other space, since classical time-of-flight lidars will be able to recognize only highly reflective objects and are not able to distinguish objects with a low reflectivity (transparent or translucent objects).

The claimed sensor device is also capable of recognizing or identifying characteristic features of the surface of transparent and opaque objects through which a beam emitted from at least one source (1 ₁ ... 1 _n ) of laser radiation propagates and / or is reflected. In this case, the recognition or identification of the structure or material of the object can be performed based on the distribution of the reflection coefficients along the ray path.

FIG. 7a shows an example of the arrangement of a fabric object, FIG. 7b is a view of a fabric structure with a denser "layer" within the fabric, and FIG. 7c is a diagram of the distribution of the reflection coefficient, along the path of the laser beam, corresponding to an example of the location of the object, which is a tissue. Fig. 7a is a diagram illustrating the propagation of a beam emitted from at least one source (1 ₁ ... 1 _n ) of laser radiation (laser) through a sufficiently extended object (for example, tissue) along the path of the beam propagation, where each object can be conditionally divided into layers, in this case the layer-by-layer separation of the piece of fabric is clearly shown in FIG. 7b and each layer of the object, along its length, contributes to the reflection. In this case, the useful signal transmitted and / or reflected from the object in this case repeats the pattern of reflection or scattering of the object. In general, each layer of the object material will reflect the beam and manifest itself as a signal indicative of the reflectivity along the path of the beam, as clearly seen in Fig.7c, where a higher peak corresponds to a higher reflectivity of the inner tissue layer.

Thus, by the distribution of the reflectivity of the object, one can judge the nature of the material from which the object is made.

Highly reflective objects such as concrete walls, metal objects, etc. reflect almost 100% of the light from their surface, resulting in a narrow peak in the signal spectrum.

Low-reflective objects, such as glass, leather, fabric, etc., reflect some of the light off the surface, and more light is reflected off the subsurface as the light enters the material. This produces a wide, uneven peak. By analyzing the shape of the peak, i.e. width and height, you can estimate the type of material of the extended object. This is clearly illustrated in the graph of FIG. 7c, which characterizes the distribution of the reflectance of the signal reflected from the tissue.

Thus, the inventive sensor device is configured to provide a high resolution image of a moving object in combination with multiple reflections detection along the beam path, which makes it possible to differentiate the target object depending on how the target objects reflect the beam from the laser source.

The authors carried out a number of experimental studies and classified the patterns of the distribution of the reflectivity of some target objects: glass, concrete (brick), fabric. Thus, the profile of the peaks characteristic of the reflection signal for various materials of objects, it is possible to recognize the materials from which the objects are made and their shape.

FIG. 9a, 9b, 9c and 9d are graphs illustrating the distribution of reflectivity depending on the material of objects (plastic, leather, fabric, glass), where the ordinate in arbitrary units denotes the reflectivity (reflection), and the abscissa is the distance in mm (i.e. the distance from the sensor device to the object, which was approximately 150 mm during the experiment).

Fig. 9a is a graph illustrating a signal obtained using a plastic plate as an object. At the same time, one can notice a large height of the signal peak and a small width on the graph.

Fig. 9b is a graph illustrating a signal obtained using human palm skin as an object. At the same time, one can notice on the graph: a low height of the structure peak (the flatter part of the peak on the right, indicating the penetration of light under the surface and reflecting from the deep layers of the object), a significant width.

Fig. 9c is a graph illustrating a signal obtained using a tissue (medical mask) as an object. At the same time, one can notice in the graph: a low peak height, a peak structure (it can be seen that it consists of two adjacent maxima) and a significant width.

Fig. 9d is a graph illustrating a signal obtained using a 20 mm thick glass plate as an object. At the same time, you can see in the graph: a large peak height, small width and the presence of two peaks (this clearly indicates reflection from two surfaces located one after the other - in this case, from the front and rear surfaces of the glass plate).

The experimental data presented in Figs. 9a-9d, in the form of graphs, clearly illustrate the significant differences in the waveforms depending on the material (structure) of the reflecting object. The waveform can be used as input data for the material type recognition algorithm.

The obtained experimental data are used to set up a machine learning algorithm designed to classify the results of the response data obtained on the detectors (7 ₁ ..7 _n ) and arriving at the main controller 9 (hereinafter referred to as the controller), where the classification of the received response data from the object is carried out based on pre-configured algorithm of the main controller 9, on the basis of which the result about the structure and shape of the object is displayed.

The claimed sensor device is also configured to measure the speed of each point of the object, which is measured simultaneously with the distance to the object, in contrast to the lidars known from the prior art, where the speed is determined based on the location of objects in two subsequent frames (by "frame" in this case is meant one measurement of distances to an object in the field of view of the device, performed simultaneously).

As an object moves, the light reflected from it experiences a frequency shift due to the Doppler effect. This shift is described by the formula:

(7)

,

,

where ω ₀ is the frequency of the incident light (Hz), V is the speed of the object (m / s), s is the speed of light (m / s).

Thus, the difference between the frequencies of the laser radiation source and the measuring signal is equal to:

(eight)

where ω ₀ is the frequency of the incident light (Hz), V is the speed of the object (m / s), s is the speed of light (m / s), L is the distance to the object (m), α is the rate of rise of the radiation frequency (Hz / s) ), i.e. the rate of measurement of the instantaneous frequency of the laser radiation emitted by the source (laser).

.For example, if a laser changes its wavelength from 852 nm (frequency = 352.1 THz) to 850 nm (frequency = 352.9 THz) in a time of 0.1 seconds, then the rate of rise of frequency is equal to

...

It can be seen from formula (8) that the measured frequency of the photodetector signal is influenced by both the distance (L) to the object and the object's velocity (V). In order to be able to separately measure the speed and distance to the object, it is proposed to carry out two measurements sequentially one after the other: first, when the rate of rise of frequency is equal to α, and then - when the rate of rise of frequency is equal to -α. (i.e. the frequency falls over time).

In this case, during the rise in frequency, the frequency Δw ₁ will be measured:

(nine)

where Δω ₁ is the frequency difference of the signals generated by the measuring and reference beams with increasing radiation frequency (Hz), ω ₀ is the frequency of the incident light (Hz), V is the object's speed (m / s), s is the speed of light (m / s) , L is the distance to the object (m), α is the rate of rise of the radiation frequency (Hz / s).

And during the fall of the frequency, the frequency Δw ₂ will be measured:

(10)

where Δω _{2 is the} difference between the frequencies of the signals generated by the measuring and reference beams at a decrease in the radiation frequency (Hz), ω ₀ is the frequency of the incident light (Hz), V is the speed of the object (m / s), s is the speed of light (m / s) , L is the distance to the object (m), α is the rate of rise of the radiation frequency (Hz / s)

Thus, the distance to the object L and its speed V can be calculated by the formula:

(eleven)

These calculations can be performed in the main controller (9).

The main effects of the claimed device

The claimed sensor device provides simultaneous measurement of the distance to the object, the speed of the object, as well as the shape and structure of the object, for example, the material of which the specified object is made.

The specified claimed device is a compact sensor designed for use in small robots and other household appliances, both inside and outside the home.

In addition, the specified sensor device is characterized by high reliability, since its design does not provide for the presence of moving mechanical parts or parts. As already indicated in the description, the operation of the sensor device is based on the interferometric method, which facilitates the operation of the claimed device both inside the house and outside the house next to bright light sources and other lidars, since the specified interferometric method provides for the detection of only light emitted by the sensor device itself and does not react to other sources of radiation, such as bright lamps, the sun, the moon and other sources of radiation, i.e. no problem with flares from other potential radiation sources.

The claimed sensor device makes it possible to simultaneously determine both the distance to the object and its speed, which makes it possible to use new algorithms for navigation. In addition, the claimed device allows obtaining data (FMCW signal), which, after some processing, characterize the structure of the object.

In addition, the claimed sensor device provides an operational change in the laser modulation parameters of the sensor device. For example, to increase the frame rate, it is necessary to increase the frequency of modulation of the current (according to the signal from the main controller 9), and to improve the resolution, it is necessary to increase the amplitude of the modulation of the pump current (according to the signal from the main controller 9), which will lead to a greater amplitude of the wavelength modulation. The specified capabilities of the sensor device according to the invention make it possible to quickly change the function of the device, for example, the sensor device can operate for navigation purposes when operating with a household vacuum cleaner, but if necessary, it is easy to rearrange the operation of the device for a small number of scanning points of the object, but with a higher resolution and high frequency frames, which ensures its operation as a gesture sensor (in this case, according to a control signal from the main controller 9, the number of simultaneously functioning sources of laser radiation is reduced (in comparison with the previous case), but the amplitude of modulation of the current supplied to these sources increases (1 ₁ ... 1 _n ) laser radiation, which increases the image resolution of the object and the frame rate), in the case of an alternating mode of operation of the sources (1 ₁ ... 1 _n ) of laser radiation, the sensor device operates as a 3-dimensional scanner. Thus, the claimed device allows you to quickly change its operating mode depending on the user's task.

In general, the output from a sensor device is the distribution of light reflecting and scattering objects (with their shape) in the surrounding space.

To work in the gesture sensor mode, the touch device can switch to a mode with a higher frame rate (for example, if in normal mode the touch device operates at a frequency of 10 frames / sec, then in the gesture sensor mode it operates at a frequency of 50 frames / sec), more high resolution (for example, if in normal mode the touch device operates with a resolution of 5 mm, then in gesture sensor mode it operates with a resolution of 0.2 mm) and a narrower field of view (for example, if in normal mode the touch device operates with a field of view of 50 ° , then in the gesture sensor mode it operates with a field of view of 15 °, by reducing the number of interrogated photodetectors). In this case, an optimal ratio of parameters is realized to obtain an image of a user's gesture.

To operate in 3D scanner mode, the sensor device can switch to a mode with a low frame rate (for example, if in normal mode the sensor device operates at a frequency of 10 frames / sec, then in a 3D scanner mode it operates at a frequency of 1 frame / sec), high resolution (for example, if in normal mode the sensor device operates with a resolution of 5 mm, then in the 3D scanner mode it operates with a resolution of 1 mm) and a large angle of view (for example, if in normal mode the sensor device operates with a field of view of 50 °, then in in 3D scanner mode, it operates with a 70 ° field of view by switching on all available photodetectors). In this case, an optimal ratio of parameters is realized for obtaining a three-dimensional image of an object, and the scanning speed does not play a significant role.

The inventors have carried out a number of studies on the parameters of such distance detecting devices used for domestic purposes, and these studies have clearly demonstrated the advantages of the claimed sensor device in comparison with known similar devices known on the market.

The following devices were considered:

(1) an optical sensor device for determining the distance and speed of objects and for recognizing its shape and structure or the material from which these objects are made (hereinafter, as a sensor device) according to the invention;

(2) flare time-of-flight lidar (Benewake C30A);

(3) a stereo camera (Stereolabs ZED) and

(4) triangulated lidar (RPLidar M8A1).

The studies were carried out according to the following criteria: 1) the determined distance, 2) the use of mechanical scanning, 3) the radius of the dead zone, 4) accuracy, 5) interference with other sensors. Table 1 clearly demonstrates the results of the studies obtained.

Criterion 1) All tested devices operate at approximately the same order of magnitude, with the exception of the stereo camera, which is capable of measuring distances up to 25 m.

Criterion 2) All devices under test, with the exception of the triangulated lidar (RPLidar M8A1), do not require mechanical scanning.

Criterion 3) All investigated devices have a certain dead zone, at which they cannot work: for a time-of-flight lidar (2) this zone is 10 cm, since at this distance the radiation intensity is too high and the sensor is illuminated, the stereo camera (3) works for account of the stereo effect provided by two cameras separated by a certain distance, called a stereo base (usually a few tens of centimeters). In this case, to observe the stereo effect, it is necessary that the observed object falls into the field of view of both cameras. Because the field of view of the cameras is limited, the area of stereoscopic vision of the stereo camera is also limited. In this case, the minimum distance for operation is comparable to the stereo base, i.e. several tens of centimeters.

For lidar (4) (RPLidar M8A1), for its operation, a minimum distance of about 15 cm is required between the emitter and the receiver, less than which it is unable to function. At the same time, for the claimed optical sensor device (1), due to its heterodyne principle of operation, there is practically no dead zone, since the distance measurement is based on measurements of the frequency difference between the emitted and received light, and zero frequency will correspond to zero difference, i.e. zero distance, i.e. the absence of a dead zone is a significant advantage of the claimed sensor device.

Criterion 4) The claimed sensor device according to the invention showed a higher resolution when measuring distance (less than 1 mm), in contrast to other devices.

Criterion 5) the claimed device (1) completely excludes the influence of interference from other devices, since it is based on the heterodyne method, devices (2) and (4) are subject to the influence of other emitting devices, which can cause measurement errors, and the stereo camera (3) is not susceptible the influence of other emitting devices, since it is a non-emitting passive device.

Thus, Table 1 clearly shows that the claimed device (1) is characterized by high accuracy (less than 1 mm), high reliability (no mechanical moving parts) and is completely unaffected by interference from other radiating devices due to the heterodyne principle of operation.

The authors conducted experimental studies to identify the shape and structure of objects using the claimed sensor device, see Fig. 10.

In Fig. 10, photographs of sectors 1-4 of the experimental laboratory are presented in the corners, and in the center of the figure there is a dark circle, in the center of which is the claimed sensor device that forms a navigation map built by a computer based on data received from the controller (9). On the dark circle, large areas (segments of straight lines) corresponding to walls and broken lines are clearly visible in sectors, small areas corresponding to small objects: cabinets, shelves, laptops.

At the same time, Fig. 11 shows in an enlarged view the details of the images from Fig. 10, where photographs of individual laboratory elements are presented on the left side of the figure, wall sills are shown on the top left in the photograph, which are displayed on the corresponding picture of the navigation map on the right, where the wall sills are clearly visible ... The photo in the middle left shows fine details and how they are displayed on the navigation map, with a resolution up to 6mm. The bottom photo on the left shows a plexiglass cube, while on the right its front and back faces are clearly visible.

Thus, the authors have clearly demonstrated the ability of the claimed sensor device to recognize the shape and structure of objects in a room.

The authors conducted experimental studies on the accuracy of measuring the speed of a moving object using the claimed sensor device (see Fig. 12). The plastic plate is placed as a moving object on a linear motor capable of speeds from 5 mm / s to 500 mm / s. Opposite the object located on the linear motor, the declared sensor device is placed according to FIGS. 2a, 2b. When starting the linear motor, the plastic plate moves at a speed of 5.16 mm / s, while the plate speed measured by the claimed sensor device is 5.27 mm / s, t .e. the measurement error is + 2.1%, when the linear motor develops a speed of 499.2 mm / s, the measurement error decreases significantly, in this case the measured speed is 495, 45 mm / s, i.e. the error is -0.8%.

Thus, the experimental studies carried out by the authors have shown a high accuracy of measurements of the object's velocity.

Industrial applicability

The optical sensor device, according to the invention, is configured to determine the distance to the object, the speed of the object, as well as the structure of the object and the material from which the object is made and can be used in sensors for navigation purposes used for mobile electronic devices, compact portable devices, as for household purposes, for example vacuum cleaners, and in other household appliances to expand their functions, in particular as a gesture sensor, and for industrial purposes for navigating an object and contactless identification of object parameters, for example, the structure and material (composition) of the object.

Claims (43)

1. Optical sensor device for determining the distance to the object, the speed of the object and for identifying the shape and structure of the object, containing: optically coupled at least one source of laser radiation, at least one optical collimating means located above the corresponding at least one source of laser radiation, beam-splitting means, reflective means, optical means for guiding the beam, configured to direct the beam in a predetermined direction to object, and at least one detector for recording radiation reflected from the object, as well as a controller connected to each of the at least one detector and at least one source of laser radiation, wherein each of the at least one laser radiation source with the corresponding at least one detector form at least one individually functioning and individually adjustable measuring channel with the possibility of providing data about the object, in this case, the controller is configured to ensure the simultaneous or selective operation of the said measuring channels and operational control of the radiation parameters of at least one laser radiation source, depending on the required operational resolution in range during the operation of the device, and processing and analysis of the object data recorded on the at least one detector for the simultaneous determination of the distance L to the object and its speed V, and recognition of the shape and structure of the object. 2. The device according to claim. 1, in which at least one source of laser radiation is a laser with a tunable wavelength. 3. The apparatus of claim 2, wherein the wavelength tunable laser is a vertical cavity surface emitting laser (VCSEL). 4. The apparatus of claim. 1, wherein the at least one laser source comprises a plurality of laser sources forming a two-dimensional array of laser sources. 5. The apparatus of claim 1, wherein the at least one detector is an array photodetector. 6. The apparatus of claim. 1, wherein the at least one detector comprises a plurality of detectors forming a two-dimensional array of detectors. 7. The device according to claim. 1, in which at least one optical collimating means is at least one microlens and is configured to collimate radiation emitted by at least one source of laser radiation. 8. The device of claim. 7, wherein the at least one microlens is a plurality of microlenses forming a two-dimensional array of microlenses. 9. The device according to claim. 1, in which the beam-splitting means is a beam-splitting cube with a semi-reflective mirror located inside the specified cube, and made with the possibility of dividing the beam into reference and measurement beams. 10. The apparatus of claim. 1, wherein the light reflecting means is a light reflecting coating applied to the inner or outer surface of the beam splitter cube and configured to re-reflect the reference beam to the corresponding detector. 11. The device according to claim. 1, in which the light reflecting means is a mirror located in front of the outer surface of the beam splitting cube and configured to re-reflect the reference beam on the corresponding at least one detector. 12. The device according to claim. 1, in which the optical means of directing the beam is a lens having a flat surface on the side facing the beam splitting cube, and on the side facing the object has a surface consisting of at least one microlens. 13. The apparatus of claim 12, wherein each of the at least one microlens corresponds to at least one laser source. 14. The device according to claim. 12, in which each of the at least one microlens is located at a predetermined angle to the corresponding incident laser beam and is made in such a way that the corresponding laser beam, after passing through the microlens, is directed in the desired predetermined direction to the object. 15. The device according to claim. 1, in which the optical means of directing the beam is a two-dimensional array of microlenses, and each microlens from the array of microlenses is located at a predetermined angle to the corresponding incident laser beam and is made in such a way that the corresponding laser beam after passing through the microlens was directed in the required specified direction towards the object. 16. The device according to claim 1, further comprising at least one driver connected to the corresponding at least one source of laser radiation and providing pumping current to it according to the control signal of the controller. 17. The device according to claim 1, further comprising an optical isolator located between the beam splitting means and at least one optical collimating means and configured to prevent the reflected light from the target object from hitting at least one source of laser radiation and prevent destabilization of the functioning of said sources ... 18. A method for determining the distance to the object, the speed of the object and for recognizing the shape and structure of the object by means of an optical sensor device for determining the distance to the object, the speed of the object and for identifying the shape and structure of the object according to one of claims. 1-17, the method contains the following steps, in which: - emitting laser radiation with a predetermined wavelength using at least one source of laser radiation, while operatively adjusting the pump current supplied to at least one source of laser radiation, depending on the required resolution of the object during the operation of the device, - direct the specified radiation to the beam splitter, where part of the radiation, representing the reference beam, is redirected to at least one detector, and the other part of the radiation, representing the measuring beam, is directed to the optical means for guiding the beam, ensuring the deflection of the specified measuring beam in a predetermined direction towards the object, further, the at least one measuring beam reflected from the object is directed to the corresponding at least one detector, on which the frequency difference of the signals generated by the measuring and reference beams is measured, on the basis of which the distance L to the object and the velocity V of the object are simultaneously determined, in this case, as the measuring beam passes through the object and / or is reflected from it, registration of the distribution of the reflection coefficient of at least one measuring beam reflected from the object, depending on the distance to the object, is provided, on the basis of which the shape and structure of the object is identified. 19. The method according to claim 18, in which the distance L (m) to the object is determined by the relationship:

, where c is the speed of light (m / s), α is the rate of rise of the radiation frequency (Hz / s), Δω ₁ is the frequency difference of the signals formed by the measuring and reference beams with increasing radiation frequency (Hz), and Δω ₂ is the frequency difference of the signals generated by the measuring and reference beams at a decrease in the radiation frequency (Hz). 20. The method according to claim 18, in which the speed V (m / s) of the object is determined by the ratio:

, where c is the speed of light (m / s), α is the rate of rise of the radiation frequency (Hz / s), ω ₀ is the frequency of the emitted light (Hz) Δω ₁ is the frequency difference of the signals formed by the measuring and reference beams with increasing radiation frequency (Hz), and Δω ₂ is the frequency difference of the signals generated by the measuring and reference beams at a decrease in the radiation frequency (Hz). 21. The method according to claim 18, wherein at the stage of regulating the pump current supplied to at least one laser radiation source, an operational change in the resolution (Res) of the object in terms of range is provided, determined by the following relationship: Res

, Where c is the speed of light (m / s), Ω - dependence of the frequency of the emitted laser light depending on the current pumped into at least one source (1 ₁ ... 1 _n ) of laser radiation (Hz / mA), dΙ is the amplitude of the modulation of the current of the laser radiation source during the scanning of the object (mA). 22. The method according to claim 18, in which the step of identifying the shape and structure of the object is carried out in the controller by comparing the obtained reflection coefficient distribution pattern of at least one measuring beam reflected from the object with known reflection coefficient distribution patterns inherent in certain object structures stored in the controller memory.

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