Lidar sensor system, autonomous vehicle control system, and autonomous vehicle

Abstract

A LIDAR sensor system, an autonomous vehicle control system, and an autonomous vehicle are provided. The LIDAR sensor system includes a first polygonal scanner including a plurality of first facets arranged about an axis of rotation, a second polygonal scanner including a plurality of second facets arranged about the axis of rotation, an optical component configured to output a first light beam to the first polygonal scanner, the first polygonal scanner configured to refract the first light beam to output a second light beam to the second polygonal scanner, the second polygonal scanner configured to refract the second light beam to output a third light beam, and at least one motor configured to rotate the first polygonal scanner about the axis of rotation and to rotate the second polygonal scanner about the axis of rotation.

Description

[0001] This application is a divisional application of National Application No. 202180034633.2 (International Application No. PCT / US2021 / 032515, International Application Date May 14, 2021, Invention Title "LIDAR System").

[0002] Cross-reference to related applications

[0003] This application claims the benefit and priority of U.S. Patent Application No. 16 / 875,114, filed May 15, 2020, the disclosure of which is incorporated herein by reference in its entirety. Background Technology

[0004] Optical distance measurement using lasers, typically referenced by the mnemonic LIDAR, is used for light detection and ranging, sometimes also called laser RADAR. It is used in a variety of applications—from altimetry to imaging to collision avoidance. LIDAR offers a finer scale of distance resolution and a smaller beam size than traditional microwave ranging systems such as radio wave detection and ranging (RADAR). Summary of the Invention

[0005] At least one aspect relates to a LIDAR system. The LIDAR system includes a first polygonal scanner, a second polygonal scanner, and optics. The first polygonal scanner includes a plurality of first facests about an axis of rotation. The second polygonal scanner includes a plurality of second facests extending outward from the plurality of first facests relative to the axis of rotation. The optics extend inward from the first polygonal scanner relative to the axis of rotation. The optics are configured to output a first beam of light to the first polygonal scanner. The first polygonal scanner is configured to refract the first beam of light to output a second beam of light to the second polygonal scanner. The second polygonal scanner is configured to refract the second beam of light to output a third beam of light.

[0006] At least one aspect relates to an autonomous vehicle control system. The autonomous vehicle control system includes a first polygon scanner, a second polygon scanner, a detector array, and one or more processors. The first polygon scanner includes a plurality of first faces about a rotation axis. The second polygon scanner includes a plurality of second faces extending outward from the plurality of first faces relative to the rotation axis. The one or more processors are configured to: rotate the first polygon scanner at a first rotation frequency; rotate the second polygon scanner at a second rotation frequency; cause a laser source to emit a first beam of light from inside the first polygon scanner onto a specific first face among the plurality of first faces, such that the specific first face refracts the first beam of light to output a second beam of light incident on the specific second face among the plurality of second faces, and the specific second face refracts the second beam of light to output a third beam of light; receive a signal from the detector array based on a fourth beam of light received at the detector array in response to the third beam of light from an object; and determine the distance to the object using the signal received from the detector array.

[0007] At least one aspect relates to an autonomous vehicle. The autonomous vehicle includes a LIDAR device and one or more processors. The LIDAR device includes a first polygonal scanner comprising a plurality of first faces about an axis of rotation. A particular first face is configured to refract a first beam to output a second beam. The LIDAR device includes a second polygonal scanner comprising a plurality of second faces extending outward from the plurality of first faces relative to an axis of rotation. A particular second face is configured to refract the second beam to output a third beam. One or more processors are configured to determine a distance to an object using a fourth beam received from the object in response to the third beam, and to use the distance to the object to control the operation of the autonomous vehicle.

[0008] Those skilled in the art will understand that the invention is illustrative only and is not intended to be limiting in any way. Any feature described herein may be used in conjunction with any other feature, and any subset of such features may be combined according to various embodiments. Other aspects, inventive features, and advantages of the apparatus and / or process described herein, as defined solely by the claims, will become apparent from the detailed description set forth herein and taken in conjunction with the accompanying drawings. Attached Figure Description

[0009] The embodiments are shown in the accompanying drawings by way of example and not limitation, wherein similar reference numerals refer to similar elements, and wherein:

[0010] Figure 1A This is a schematic graph illustrating an example transmitted signal of a series of binary numbers according to an embodiment and a returned optical signal used for measuring distance;

[0011] Figure 1BIt is a schematic graph showing an example spectrum of a reference signal and an example spectrum of a return signal after Doppler frequency shift according to an embodiment;

[0012] Figure 1C This is a schematic graph showing an example cross spectrum of the phase component of the Doppler-shifted return signal according to an embodiment;

[0013] Figure 1D This is a set of graphs showing example optical chirp measurements of distance according to an embodiment;

[0014] Figure 1E is a graph of the use of a symmetrical LO signal according to an embodiment, and shows the return signal in the frequency time graph as a dashed line when there is no Doppler shift.

[0015] Figure 1F It is a graph similar to that in FIG1E using a symmetrical LO signal according to the implementation method, and shows the return signal in the frequency time graph as a dashed line when there is a non-zero Doppler frequency shift.

[0016] Figure 2A This is a block diagram illustrating example components of a high-resolution (high res) LIDAR system according to an embodiment;

[0017] Figure 2B This is a block diagram illustrating a sawtooth scanning pattern used in some embodiments for a high-resolution Doppler system.

[0018] Figure 2C This is an image showing an example velocity point cloud generated by a high-resolution Doppler LIDAR system according to an embodiment;

[0019] Figure 2D This illustrates an embodiment. Figure 2A A block diagram of an example component of the scanning optical part of the system;

[0020] Figure 2E This is a block diagram illustrating an example system including at least one high-resolution LIDAR system mounted on a vehicle, according to an embodiment.

[0021] Figure 3 This is a block diagram illustrating an example of a conventional assembly including a polygonal reflector that is rotated by a motor to reflect an incident beam across the field of view;

[0022] Figure 4 This is a block diagram illustrating an example of an assembly according to an embodiment, including a polygonal deflector rotated by a motor to refract an incident light beam from inside the deflector.

[0023] Figure 5AThis is a schematic diagram illustrating an example of a cross-sectional side view of an assembly according to an embodiment, including a polygonal deflector rotated by a motor to refract an incident light beam from inside the deflector.

[0024] Figure 5B This illustrates an embodiment. Figure 5A A schematic diagram of an example of a cross-sectional top view of a polygonal deflector;

[0025] Figure 5C This illustrates an embodiment. Figure 5A A schematic diagram of an example side view of a planar fiber array of assemblies;

[0026] Figure 5D This illustrates an embodiment. Figure 5A A schematic diagram of an example side view of a lens assembly;

[0027] Figure 5E This illustrates the two rotational positions according to the embodiment. Figure 5B A schematic diagram of an example of a polygon deflector;

[0028] Figure 5F This illustrates an embodiment. Figure 5A A schematic diagram of an example of a partial cross-sectional side view of a polygonal deflector;

[0029] Figure 5G This illustrates an embodiment. Figure 5A A schematic diagram of an example cross-sectional view of a toric lens used in an assembly;

[0030] Figure 6 This is a flowchart illustrating an example method for optimizing a scanning pattern of a light beam in a first plane between a first angle and a second angle, according to an embodiment.

[0031] Figure 7 This is a schematic diagram illustrating an example of a LIDAR system including two polygon scanners according to an embodiment;

[0032] Figure 8 This is a schematic top view showing an example of two polygon scanners according to an embodiment;

[0033] Figure 9 This is a schematic cross-sectional view illustrating an example of two polygon scanners according to an embodiment;

[0034] Figure 10 This is a graph showing examples of elevation and azimuth angles sampled using a LIDAR system according to an embodiment;

[0035] Figure 11This is a flowchart illustrating an example of a method for operating a LIDAR system according to an embodiment;

[0036] Figure 12 This is a block diagram illustrating a computer system according to an embodiment; and

[0037] Figure 13 A chipset according to an embodiment is shown. Detailed Implementation

[0038] A method, apparatus, system, and computer-readable medium for scanning a LiDAR system are described. Some embodiments are described below within the context of a high-resolution LiDAR system. One embodiment is described in a context optimizing scanning of a beam through a unidirectional scanning element of a LiDAR system (including Doppler and non-Doppler LiDAR systems). Another embodiment is described in a context optimizing scanning of a beam through a polygonal deflector, such as one configured to deflect or refract an incident beam onto a polygonal deflector surface from within the deflector. The polygonal deflector can be a polygonal shaped element with many faces based on a polygonal structure. Each face is configured to deflect in the field of view as the polygonal deflector rotates about an axis (e.g., reflecting the incident beam onto the face or refracting the incident beam from within the polygonal shaped element). The polygonal deflector repeatedly scans the beam in the field of view during rotation of the polygonal deflector, as the beam transitions over face breaks between adjacent faces. Some embodiments are described in the context of a single front-facing high-resolution Doppler LiDAR system in a personal vehicle; however, various embodiments are not limited to this context. Some implementations can be used in environments involving laser etching, surface treatment, barcode scanning, and beam refraction scanning.

[0039] Some scanning systems utilize polygonal reflectors, which are regularly shaped reflective objects that rotate relative to a static incident beam. The reflecting surface causes repeated reflections of light in the direction of the field of view. Such polygonal reflectors can have several disadvantages. For example, the incident beam on the reflecting surface inherently limits the field of view because the field of view cannot include the angle containing the incident beam coplanar with the reflecting surface. If the field of view extends to include the angle containing the incident beam and is therefore inherently limited by the incident beam, useful return beam data cannot be obtained. This can also inherently limit the duty cycle or time ratio to the total operating time of the polygonal reflector when scanning the beam across the field of view. Various systems and methods according to this disclosure can use a refraction beam-direction assembly and method utilizing a polygonal deflector that deflects (e.g., refracts) the incident beam across the field of view rather than reflecting it. The polygonal deflector can enhance both the field of view and the duty cycle because the incident beam is guided from within the deflector and therefore does not inherently limit the field of view.

[0040] A LiDAR device can scan a light beam in a first plane between a first angle and a second angle. The device includes: a polygonal deflector comprising a plurality of faces; and a motor rotatably coupled to the polygonal deflector and configured to rotate the polygonal deflector about a first axis orthogonal to the first plane. The device also includes optical components positioned inside the polygonal deflector to collimate a light beam incident on the faces from inside the polygonal deflector. Each face is configured to refract the light beam in the first plane between the first and second angles as the polygonal deflector rotates about the first axis. Systems and methods for implementing this LiDAR device can be provided.

[0041] 1. Overview of Phase-Encoded Detection

[0042] Distance is measured using optical phase-coded signals. The transmitted signal is in phase with a portion of the carrier wave (phase = 0), and then alternating between two or more phase values ​​in the transmitted signal over short time intervals by one or more phase changes represented by the symbol Δφ (so phase = Δφ). The shortest interval for a constant phase is called the pulse duration. The encoding parameters, and typically the duration of several time periods at the lowest frequencies in the frequency band. Reciprocal, 1 / , where baud indicates one symbol. The number N of such constant-phase pulses during the transmission time is N, which is the number of symbols and represents the code length. In binary coding, there are two phase values; the shortest interval between phases can be considered as one value being 0 and the other 1, thus a symbol is 1 bit, and the baud rate is also called the bit rate. In polyphase coding, there are multiple phase values. For example, four phase values, such as Δφ. For {0, 1, 2, and 3}, for Δφ = / 2 (90 degrees), respectively equal to {0, / 2, and 3 / 2}; and thus, the four phase values ​​can represent 0, 1, 2, 3 respectively. In this example, each symbol is 2 bits, and the bit rate is twice the baud rate.

[0043] Phase Shift Keying (PSK) is a digital modulation scheme that transmits data by changing the phase of a reference signal (carrier). Changing the sine and cosine inputs at precise timing profoundly affects the modulation. In radio frequency (RF) communication, PSK is widely used in wireless local area networks (LANs), RFID, and Bluetooth communications. Alternatively, instead of operating with respect to a constant reference wave, transmission can operate with respect to itself. The phase change of a single transmitted waveform can be considered a symbol. In this system, the demodulator determines the phase of the received signal rather than the change in phase (relative to the reference wave) itself. Because this scheme depends on the difference between successive phases, it is called Differential Phase Shift Keying (DPSK). DPSK can be implemented significantly more simply in communication applications than ordinary PSK because it does not require the demodulator to have a copy of the reference signal to determine the precise phase of the received signal (and is therefore an incoherent scheme).

[0044] Optical distance detection can be accomplished using several different techniques, including direct ranging based on the round-trip time of the optical pulse to the object, chirped detection based on the frequency difference between the emitted chirped optical signal and the returned signal scattered from the object, and phase-coded detection based on a single-frequency phase change sequence that can be distinguished from natural signals.

[0045] To achieve acceptable range accuracy and detection sensitivity, direct long-range LiDAR systems may use short-pulse lasers with low pulse repetition rates and extremely high peak power. High pulse power can lead to rapid degradation of the optical components. Chirped and phase-coded LiDAR systems can use long optical pulses with relatively low peak optical power. In this configuration, range accuracy can increase with the chirp bandwidth or length and the bandwidth of the phase code, rather than the pulse duration, thus still achieving excellent range accuracy.

[0046] Useful optical bandwidths have been achieved by modulating optical carriers with broadband radio frequency (RF) electrical signals. In the case of LiDAR, using the same modulated optical carrier as a reference signal (combined with the return signal at the optical detector), a relatively low beat frequency in the RF band can be generated in the resulting electrical signal, proportional to the frequency or phase difference between the reference signal and the return optical signal. This beat frequency detection at the detector is called heterodyne detection. Heterodyne detection has several advantages known in the art, such as the readily available and inexpensive availability of RF components.

[0047] High-resolution range-Doppler LIDAR systems can use the arrangement of optical components and coherent processing to detect the Doppler frequency shift in the returned signal, thereby providing improved distance and relative signed velocity in the vector between the LIDAR system and each external object.

[0048] In some instances, these enhancements provide distance, with or without target velocity, within a fine-pitch laser beam of appropriate frequency or phase content. As such a beam sweeps across a scene, information about the position and velocity of surrounding objects can be obtained. This information can then be used in the control systems of autonomous vehicles, such as self-driving or driver-assisted cars.

[0049] For optical ranging applications, coherent PSK can be used because the transmitter and receiver are in the same device. The carrier frequency is the optical frequency fc, and RF f0 is modulated onto the optical carrier. The number N of selected symbols and the duration... The length of the symbol is chosen to achieve the desired distance accuracy and resolution. A pattern of symbols is selected so that it is distinguishable from other sources of coded signal and noise. Therefore, a strong correlation between the transmitted and returned signals can be a strong indication of the reflected or backscattered signal. The transmitted signal consists of one or more symbol blocks, where each block is long enough to provide a strong correlation with the reflected or backscattered return signal even in the presence of noise. The transmitted signal can consist of M blocks, each containing N symbols, where M and N are non-negative integers.

[0050] Figure 1A This is a schematic graph 120 illustrating an example transmitted signal as a series of binary numbers according to an embodiment, and a returned optical signal used for distance measurement. The horizontal axis 122 indicates any unit of time after the start time at zero. The vertical axis 124a indicates the amplitude of the optical transmitted signal at an arbitrary frequency fc+f0 relative to zero. The vertical axis 124b indicates the amplitude of the optical returned signal at an arbitrary frequency fc+f0 relative to zero, and is offset from axis 124a to separate the trace. Trace 125 represents M. The phase change of the transmitted signal of N binary symbols is as follows: Figure 1A As shown, this generates a code that begins with 00011010 and continues as indicated by the ellipsis. Trace 126 represents an idealized (noise-free) return signal scattered from a stationary object (therefore the return has no Doppler shift). The amplitude is reduced, but the code 00011010 is identifiable. Trace 127 represents an idealized (noise-free) return signal scattered from a moving object and therefore Doppler-shifted. The return is not at the appropriate optical frequency fc+f0 and is not well detected in the expected frequency band, hence the reduced amplitude.

[0051] The observed frequency f' returned differs from the correct frequency f = fc + f0 returned by the Doppler effect given by Equation 1.

[0052] (1)

[0053] Where c is the speed of light in the medium, vo v is the velocity of the observer. s Let f be the velocity of the source along the vector connecting the source and the receiver. It should be noted that if the observer and the source move in the same direction with the same velocity along the vector between them, then the two frequencies are the same. The difference between the two frequencies, Δf = f' - f, is the Doppler frequency shift Δf. D This raises the issue of distance measurement, as given by Equation 2.

[0054] (2)

[0055] It should be noted that the magnitude of the error increases with the signal frequency f. It should also be noted that for stationary LiDAR systems (v... o = 0), for a speed of 10 meters per second (v s = 10) Moving objects, and visible light with a frequency of approximately 500 THz, have an error of approximately 16 MHz (1 MHz = 10 THz). 6 Hertz (Hz, 1 Hz = 1 cycle per second). In the various implementations described below, Doppler frequency shift error is detected and used to process data for distance calculation.

[0056] In phase-coded ranging, the arrival of a phase-coded reflection can be detected in the return signal by cross-correlating the transmitted signal or other reference signal with the returned signal. This cross-correlation can be implemented by using heterodyne detection to cross-correlate the code used for the RF signal with the electrical signal from the optical detector, and thus downmixing it back to the RF band. The cross-correlation for any hysteresis can be calculated by convolving the two traces, for example, by multiplying the corresponding values ​​in the two traces and summing over all points in the traces, and then repeating for each hysteresis. Cross-correlation can also be implemented by multiplying the Fourier transforms of each of the two traces and then performing an inverse Fourier transform. Forward and inverse Fast Fourier Transforms can be implemented efficiently in both hardware and software.

[0057] It should be noted that after the amplitude and phase of the returned signal are detected at the optical detector, cross-correlation calculations can be performed using analog or digital electrical signals. To shift the signal at the optical detector into an RF frequency range that can be easily digitized, the optical return signal is optically mixed with a reference signal before impacting the detector. A phase-encoded copy of the transmitted optical signal can be used as the reference signal, but it is also possible, and generally preferred, to use a continuous-wave carrier frequency optical signal output from a laser as the reference signal, capturing both the amplitude and phase of the electrical signal output from the detector.

[0058] For an idealized (noise-free) return signal reflected from a stationary object (and thus, the return is not Doppler shifted), the peak occurs at time Δt after the start of the emitted signal. This indicates that the return signal includes a version of the phase code of the emission starting at time Δt. The distance R to the reflecting (or backscattering) object is calculated from a two-way travel time delay based on the speed of light c in the medium, as given in Equation 3.

[0059] (3)

[0060] For an idealized (noise-free) return signal scattered from a moving object (and thus, the return is Doppler-shifted), the return signal does not include phase encoding within the appropriate frequency window (bin), the correlation remains low across all time lags, and the peaks are not easily detected and are generally undetectable in the presence of noise. Consequently, Δt is not easily determined, and the distance R is not easily generated.

[0061] The Doppler frequency shift can be determined during the electrical processing of the returned signal, and the Doppler frequency shift can be used to correct cross-correlation calculations. Therefore, peaks can be detected more easily, and distances can be determined more easily. Figure 1B This is a schematic graph 140 showing example spectra of the transmitted signal and example spectra of the Doppler-shifted complex return signal according to the implementation. The horizontal axis 142 indicates an arbitrary unit of RF frequency shift from the optical carrier fc. The vertical axis 144a indicates the magnitude of a specific narrow frequency window relative to zero, also known as the spectral density. The vertical axis 144b indicates an arbitrary unit of spectral density relative to zero and is offset from axis 144a to separate the traces. Trace 145 represents the transmitted signal; and, it peaks at the appropriate RF f0. Trace 146 represents an idealized (noise-free) complex return signal, which is backscattered from an object moving towards the LIDAR system and thus Doppler-shifted to a higher frequency (called a blue shift). The return has no peak at the appropriate RF f0; instead, it is blue-shifted Δf. D to the frequency f after frequency shift S In practice, a complex return representing the in-phase and quadrature (I / Q) components is used to determine +Δf. D The peak value at that point allows the direction of the Doppler frequency shift to be detected from a single return, as well as the direction of motion of the target in the vector between the sensor and the object.

[0062] In some Doppler compensation implementations, Δf is not found by acquiring the spectra of the transmitted and returned signals and searching for the peak of each signal, then subtracting the frequency of the corresponding peak. D ,like Figure 1BAs shown in the figure, instead of obtaining the cross spectrum of the in-phase and quadrature components of the downmixed return signal in the RF band, it is possible to obtain the cross spectrum of the in-phase and quadrature components more efficiently. Figure 1C This is a schematic graph 150 illustrating an example cross spectrum according to an embodiment. The horizontal axis 152 indicates a frequency shift of arbitrary units relative to a reference spectrum; and the vertical axis 154 indicates the amplitude of the cross spectrum of arbitrary units relative to zero. Trace 155 represents the cross spectrum with an idealized (noise-free) return signal, which is shifted towards the LIDAR system ( Figure 1B blue shift Δf D1 = Δf D An object moving away from the LIDAR system (redshift Δf) D2 The second object is generated when one of its components is blue-shifted by Δf. D1 A peak value of 156a appears; and when a component is redshifted by Δf D2 Another peak of 156b appears. Therefore, the Doppler frequency shift is determined. These shifts can be used to determine the signed velocity of approaching objects near LiDAR, such as for collision avoidance applications. However, without I / Q processing, the peak may appear at + / - Δf. D1 Both and + / - Δf D2 Therefore, in both cases, there may be ambiguity in the sign of the Doppler shift and thus in the direction of motion.

[0063] The Doppler shift detected in the cross-spectrum can be used to correct the cross-correlation, making the peak 135 apparent in the Doppler-compensated Doppler shift return at hysteresis Δt, and allowing the distance R to be determined. In some implementations, simultaneous I / O processing can be performed. In some implementations, serial I / Q processing can be used to determine the sign of the Doppler return. In some implementations, errors caused by the Doppler shift may be tolerated or ignored; and no Doppler correction is applied to the distance measurement.

[0064] 2. Overview of Chirp Detection

[0065] Figure 1D This is a set of graphs illustrating example optical chirp measurements of distance according to an embodiment. The horizontal axis 102 is the same for all four graphs and indicates time in arbitrary units, milliseconds (ms, 1 ms = 10⁻⁶). -3 On the order of seconds. Graph 100 indicates the power of the beam used as the emitted optical signal. The vertical axis 104 in graph 100 indicates the power of the emitted signal in arbitrary units. Trace 106 indicates the power over a finite pulse duration. Turn on the power inside, It begins at time 0. Graph 110 indicates the frequency of the transmitted signal. Vertical axis 114 indicates the frequency transmitted within any unit. Trace 116 indicates the pulse frequency over the pulse duration. The bandwidth increases from f1 to f2, thus having a bandwidth B = f2 - f1. The rate of frequency change is (f2 - f1) / .

[0066] The return signal is depicted in graph 160, which has a horizontal axis 102 indicating time and a vertical axis 114 indicating frequency, identical to graph 110. The chirp of graph 110 (e.g., frequency envelope 116) is also plotted as a dashed line on graph 160. The first return signal is given by frequency envelope 166a, which can represent a transmitted reference signal that is attenuated in intensity (not shown) and delayed by Δt. When the return signal is received from an external object after covering a gap of 2R, where R is the distance to the target, the return signal starting at the delay time Δt can be given by 2r / c, where c is the speed of light in the medium (approximately 3 x 10⁻⁶). 8 The frequency (meters per second, m / s) is related to Equation 3 above. During this time, the frequency has changed by a quantity dependent on the distance, called f. R This is given by multiplying the rate of change of frequency by the delay time. This is given by equation 4a.

[0067] (4a)

[0068] f R The value of can be measured by the frequency difference between the transmitted signal 116 and the returned signal 166a in a time-domain mixing operation known as dechirping. Therefore, the range R is given by equation 4b.

[0069] (4b)

[0070] If the return signal arrives after the pulse has been fully transmitted, that is, if 2R / c is greater than 1 / 2 If the reference signal is delayed by a known or fixed amount, then equations 4a and 4b are invalid. In this case, the reference signal can be delayed by a known or fixed amount to ensure that the returned signal overlaps with the reference signal. The fixed or known delay time of the reference signal can be multiplied by the speed of light c to give an additional distance, which is added to the distance calculated from equation 4b. Although this may deviate from the absolute distance due to the uncertainty of the speed of light in the medium, it is a nearly constant error, and the relative distance based on the frequency difference remains very accurate.

[0071] In some cases, the illuminated spot (beam cross-section) encounters two or more distinct scatterers at different distances, such as the front and back of a translucent object, or the closer and farther portions of an object at varying distances from the LiDAR, or two separate objects within the illuminated spot. In such cases, a second signal with reduced intensity and varying delay will also be received, indicated by trace 166b on graph 160. This will have f at different distances given by equation 4b. R Different measured values. In some cases, multiple additional return signals are received.

[0072] Graph 170 depicts the difference frequency f between the first return signal 166a and the reference chirp 116. R The horizontal axis 102 indicates the time, and... Figure 1D As with all other aligned plots, the vertical axis 164 indicates the frequency difference on a much larger scale. Trace 176 depicts the constant frequency f measured in response to the emitted chirp. R This indicates a specific distance as given in Equation 4b. If present, the second return signal 166b will generate a different, larger f during the dechirping process. R Value (not shown); therefore, Equation 4b produces a larger distance.

[0073] Dechirping can be performed by directing both the reference and return optical signals to the same optical detector. The detector's electrical output can be governed by a beat frequency equal to or otherwise dependent on the frequency difference between the two signals converging on the detector. The Fourier transform of this electrical output signal will produce a peak at the beat frequency. This beat frequency is in the megahertz (MHz, 1 MHz = 10^64 MHz) range. 6 Hertz = 10 per second 6 The radio frequency (RF) range (number of cycles) instead of the terahertz (THz, 1THz = 10^6 cycles) range. 12 The optical frequency range is within the range of Hertz. Such signals can be processed by RF components, such as Fast Fourier Transform (FFT) algorithms running on a microprocessor or specially built FFT or other digital signal processing (DSP) integrated circuits. The returned signal can be mixed with a continuous wave (CW) as a local oscillator (instead of a chirp as a local oscillator). This causes the detected signal to be chirped (or whatever waveform was transmitted). In this case, the detected signal can undergo matched filtering in the digital domain, although the bandwidth requirements of the digitizer are typically high. The positive aspects of coherent detection are preserved in other ways.

[0074] In some implementations, the LIDAR system is modified to produce simultaneous up and down chirps. This method can eliminate variability caused by object velocity differences, or changes in the LIDAR's position relative to an object whose distance has actually changed, or transient scatterers in the beam, or combinations thereof. The method guarantees that the Doppler frequency shift and distance measured on the up and down chirps are indeed identical and can be combined most usefully. The Doppler scheme can guarantee parallel capture of the return pairs of asymmetric frequency shifts in the frequency space to obtain correct compensation with a high probability.

[0075] Figure 1E is a graph using a symmetrical LO signal according to an embodiment, showing the return signal in the frequency-time graph represented by the dashed line when there is no Doppler shift. The horizontal axis indicates 10. -5 A time unit in the form of seconds (tens of microseconds). The vertical axis indicates the optical transmitted signal relative to the carrier frequency f. c Or the frequency of the reference signal, in gigahertz (10 9 Hertz (Hz) is used as an example unit. During the duration of a pulse, a beam of light is generated at any given time comprising two optical frequencies. One frequency increases from f1 to f2 (e.g., 1 to 2 GHz above the optical carrier), while the other frequency simultaneously decreases from f4 to f3 (e.g., 1 to 2 GHz below the optical carrier). The two frequency bands (e.g., band 1 from f1 to f2, and band 2 from f3 to f4) do not overlap, such that both the transmitted and returned signals can be separated by high-pass or low-pass filters or some combination of optical separations, with the passband extending from the passband f... p Let's begin. For example, f1 < f2 < f p < f3 < f4. As shown in the figure, the higher frequency can provide the up-chirp, and the lower frequency can provide the down-chirp. In some implementations, the higher frequency generates the down-chirp, and the lower frequency generates the up-chirp.

[0076] In some implementations, two different laser sources are used to generate two different optical frequencies in each beam at each time. In some implementations, a single optical carrier is modulated by a single RF chirp to produce symmetrical sidebands that serve as simultaneous up and down chirps. In some implementations, a double-sideband Mach-Zehnder intensity modulator is used, which typically does not leave much energy in the carrier frequency; instead, almost all the energy goes into the sidebands.

[0077] Because of sideband symmetry, the bandwidths of two optical chirps can be the same if sidebands of the same order are used. In some implementations, other sidebands are used, for example, two second-order sidebands, or a first-order sideband and a non-overlapping second sideband, or some other combination.

[0078] When selecting the transmit (TX) and local oscillator (LO) linear frequency modulation waveforms, it is advantageous to ensure that the system's frequency shift band utilizes the available digital converter bandwidth to the maximum extent. Typically, this is achieved by increasing or decreasing the chirp frequency shift to bring the distance frequency beat close to zero.

[0079] Figure 1F This is a graph similar to Figure 1E using a symmetrical LO signal, showing the return signal in the time plot at that frequency as a dashed line when a non-zero Doppler shift is present. In the case of chirped waveforms, time-separated I / Q processing (also known as time-domain multiplexing) can be used to overcome the hardware requirements of other methods. In this case, AOM can be used to break the distance-Doppler ambiguity of real-valued signals. In some implementations, a scoring system can be used to pair the upper and lower chirped returns. In some implementations, I / Q processing can be used to determine the sign of the Doppler chirp.

[0080] 3. Overview of Optical Inspection Hardware

[0081] Figure 2A This is a block diagram illustrating example components of a high-resolution ranging LIDAR system 200 according to an embodiment. Optical signals are indicated by arrows. Electronic wired or wireless connections are indicated by segmented lines without arrows. A laser source 212 emits a beam (e.g., carrier 201) phase- or frequency-modulated in modulator 282a before or after beamsplitter 216 to generate a phase-coded or chirped optical signal 203 with a duration D. Beamsplitter 216 splits the modulated (or, as shown, unmodulated) optical signal for use in reference path 220. Target beam 205, also referred to herein as the emitted signal, can generate most of the energy of beam 201. A modulated or unmodulated reference beam 207a can also be generated, which can have a much smaller amount of energy, still sufficient to produce good mixing with the reflected light 291 scattered from an object (not shown). Figure 2AAs shown, reference beam 207a is individually modulated in modulator 282b. Reference beam 207a travels through reference path 220 and is guided as reference beam 207b to one or more detectors. In some embodiments, reference path 220 introduces a known delay sufficient to allow reference beam 207b to reach detector array 230 within the range of interest along with scattered light from objects outside the LIDAR. In some embodiments, reference beam 207b is referred to as the local oscillator (LO) signal, such as if reference beam 207b were locally generated from a single oscillator. In various embodiments, from fewer to more flexible methods, reference beam 207b can be induced to reach the scattering or reflecting field by: 1) placing a mirror in the scene to reflect a portion of the emitted beam back to the detector array, such that the path length is well matched; 2) using fiber delay to achieve a tight path length match and broadcasting the reference beam using optics near the detector array, such as... Figure 2A The proposed methods include: 1) using path length adjustment, with or without, to compensate for phase or frequency differences observed or anticipated within a specific distance; or 2) using a time delay of frequency-shifting devices (acousto-optic modulators) or local oscillator waveform modulation (e.g., in modulator 282b) to generate individual modulation to compensate for path length mismatch; or a combination thereof. In some implementations, the objects are close enough and the emission duration is long enough that the returned reference signal is sufficiently overlapped without delay.

[0082] The transmitted signal is then emitted to illuminate the area of ​​interest, such as through one or more scanning optics 218. The detector array can be a single paired or unpaired detector or a one-dimensional (1D) or two-dimensional (2D) array of paired or unpaired detectors arranged in a plane generally perpendicular to the return beam 291 from the object. The reference beam 207b and the return beam 291 can be combined in zero or more optical mixers 284 to generate an optical signal of the characteristic to be properly detected. The frequency, phase, or amplitude of the interference pattern, or some combination thereof, can be recorded by the acquisition system 240 for each detector at multiple times during the signal duration D. The number of time samples processed per signal duration or integration time may affect the range. The number or integration time can be a practical consideration based on the number of symbols per signal, the signal repetition rate, and the available camera frame rate. The frame rate is the sampling bandwidth, often referred to as the "digital converter frequency". The only fundamental limitation to the range is the coherence length of the laser, and the length of the chirp or unique phase code before repetition (for explicit ranging). This is enabled because any digital record of the returned heterodyne signal or bit can be compared or cross-correlated with any portion of the transmitted bits from previous transmission history.

[0083] The collected data can be used to process system 250, as shown in the following reference. Figure 7 The computer system described, or the reference below Figure 7 The chipset described. Scanner control module 270 provides scan signals to drive scan optics 218. Scanner control module 270 may include instructions to perform actions related to… Figure 6 The flowchart relates to one or more steps of method 600. A signed Doppler compensation module (not shown) in processing system 250 can determine the sign and magnitude of the Doppler frequency shift, and the correction range and any other corrections based on it. Processing system 250 may include a modulation signal module (not shown) to transmit one or more electrical signals driving modulators 282a, 282b. In some embodiments, the processing system also includes a vehicle control module 272 to control a vehicle on which system 200 is mounted.

[0084] Optical couplings used for diffusing or focusing on a target or for focusing across the pupil plane are not described. The optical couplers used herein are any components that affect the propagation of light in spatial coordinates to guide light from one component to another, such as vacuum, air, glass, crystal, mirror, lens, optical circulator, beam splitter, phase plate, polarizer, optical fiber, optical mixer, etc., either individually or in some combination.

[0085] Figure 2A Example components for a simultaneously up-and-down chirped LIDAR system, according to an embodiment, are also shown. Figure 2A As depicted, modulator 282a can be a frequency shifter added to the optical path of the transmitted beam 205. In some embodiments, the frequency shifter is added to the optical path of the returned beam 291 or to the reference path 220. The frequency shifter can be added as modulator 282b to the local oscillator (LO, also known as the reference path) side or the transmit side (before the optical amplifier) ​​because devices used as modulators (e.g., acousto-optic modulators, AOM) have some associated losses, so placing a lossy component on the receive side or after the optical amplifier may be disadvantageous. An optical frequency shifter can shift the frequency of the transmitted signal (or returned signal) relative to the frequency of the reference signal by a known amount Δfs, such that the beat frequencies of the upper and lower chirps occur in different frequency bands—beat frequencies can be picked up by, for example, the FFT component in the processing system 250 when analyzing the electrical signal output by the optical detector 230. For example, if the blue shift causing the distance effect is f B Then the beat frequency of the chirp will be shifted and increased at f B It occurs at +Δfs, and the beat frequency of the downchirped frequency will be shifted and reduced to f. B– Δfs. Therefore, the upper chirp will be in a higher frequency band than the lower chirp, thus separating them. If Δfs is greater than any expected Doppler effect, there will be no ambiguity in the distances associated with the upper and lower chirps. The measured beat can then be corrected with the correct sign value of the known Δfs to obtain the appropriate upper and lower chirp distances. In some embodiments, the RF signal from the balanced detector is directly digitized, and the frequency bands are separated via FFT. In some embodiments, the RF signal from the balanced detector is preprocessed with analog RF electronics to separate the low-frequency bands that can be directly digitized (corresponding to one of the upper and lower chirps), and the high-frequency bands that are electronically downmixed to baseband and then digitized (corresponding to the opposite chirp). Various such embodiments provide a path to match the frequency bands of the detected signal with available digital converter resources. In some embodiments, modulator 282a is excluded (e.g., direct ranging).

[0086] Figure 2B This is a block diagram illustrating a sawtooth scanning pattern used in a high-resolution Doppler system. The scan sweeps across a series of azimuth angles (e.g., horizontally along axis 222) and tilt angles (e.g., vertically above and below the zero-tilt horizontal direction along axis 224). Various scanning modes can be used, including adaptive scanning. Figure 2C This is an image showing an example velocity point cloud generated by a high-resolution Doppler LIDAR system.

[0087] Figure 2D It is shown Figure 2A A block diagram of an example component of the scanning optics 218 of system 200. In one embodiment, the scanning optics 218 is a dual-element scanning system including: an oscillating scanning element 226 that controls the actuation of the beam 205 along an axis (e.g., along...). Figure 2B The axis 222 is between angles -A and +A; and a unidirectional constant velocity scanning element 228 (e.g., a polygon deflector) controls the actuation of the beam 205 along another axis in one direction (e.g., along...). Figure 2B (Axis 224). Scanning optical component 218 can be used for Figure 2ASystem 200. Scanning optics 218 can be used in systems other than LiDAR systems, such as System 200, including laser etching, surface treatment, barcode scanning, and beam refraction scanning. In some embodiments, an oscillating scanning element 226 is provided without a unidirectional scanning element 228, or in other embodiments, a unidirectional scanning element 228 is provided without an oscillating scanning element 226. In one embodiment, the oscillating scanning element 226 actuates the beam 205 in opposite directions along axis 222 between angles -A and +A, because the unidirectional constant-velocity scanning element 228 simultaneously actuates the beam 205 in one direction along axis 224. In one embodiment, the actuation speed of the oscillating scanning element 226 is bidirectional and greater than the unidirectional actuation speed of the constant-velocity scanning element 228, such that for each instance where the beam is scanned along axis 224 (e.g., from angle =D to +D), the beam 205 is scanned back and forth along axis 222 multiple times (e.g., between angles -A and +A).

[0088] In some embodiments, the scanner control module 270 provides signals transmitted from the processing system 250 to the motor 232, which is mechanically coupled to the oscillating scanning element 226 and / or the unidirectional scanning element 228. In one embodiment, two motors are provided, one mechanically coupled to the oscillating scanning element 226 and the other mechanically coupled to the unidirectional scanning element 228. In one embodiment, based on signals received from the processing system 250, the motor 232 rotates the oscillating scanning element 226 and / or the unidirectional scanning element 228 based on the values ​​of parameters (e.g., angular velocity, etc.) in the signals. The scanner control module 270 can determine the values ​​of the parameters in the signals such that the beam 205 is scanned by the oscillating scanning element 226 in a desired scanning pattern (e.g., along axis 222 between angles -A and +A) and / or by the unidirectional constant-velocity scanning element 228 in a desired scanning pattern (e.g., along axis 224 between angles =D and +D).

[0089] 4. Coherent LiDAR system for redirecting refracted beams

[0090] Figure 3 It is shown that the rotation is achieved by a motor (not shown) to the field of view 310 (e.g., in the field of view 310). Figure 3This is a block diagram of an example assembly 300 of a polygonal reflector 304 that reflects an incident beam 311 within a plane between a first angle and a second angle. The polygonal reflector 304 includes a plurality of reflecting surfaces 306 (e.g., six in a hexagonal reflector). Each surface 306 reflects the incident beam 311 into a reflected beam 312, which defines a field of view 310 as the reflector 304 rotates about an axis of rotation. The field of view 310 can be defined when the incident beam 311 encounters first and second interruptions in the surfaces 306. The field of view 310 can be limited by the position of the incident beam 311, which is coplanar with the surfaces 306, because the field of view 310 cannot include angles coinciding with the incident beam 311. The field of view 310 cannot include the incident beam 311 because useful return beam data cannot be collected for those scanning angles. Thus, the polygonal reflector 304 has a finite field of view 310 due to the coplanarity of the incident beam 311 and its incident on the outer surface of the surfaces 306. The field of view 310 can limit the duty cycle of the polygonal reflector 304, which is defined as the ratio of the time it takes for the surface 306 to reflect the beam 312 onto the field of view 310 to the total operating time of the assembly 300. This duty cycle can be approximately 50% of that of a conventional polygonal reflector 304.

[0091] Figure 4 This is a block diagram illustrating an example of an assembly 400 including a polygonal deflector 404 rotated by a motor 232 to deflect an incident beam 411 from inside a deflector 404. The polygonal deflector 404 may include a unidirectional constant-speed scanning element 228, which can be... Figure 2AThe system 200 may or may not use a unidirectional constant-velocity scanning element 228. An incident beam 411 can be shaped (e.g., collimated) by an optical component 405 (e.g., one or more lenses or mirrors) positioned within the interior 432 of the polygonal deflector 404. The incident beam 411 can be guided from outside the polygonal deflector 404 to the interior 432 before being shaped by the optical component 405 within the interior 432. In some embodiments, multiple incident beams 411 are provided and shaped by the optical component 405 before being guided to the surface 406. The surface 406 can refract the incident beam 411 into a refracted beam 412 based on Snell's law, according to the refractive index of the surface 406 and the angle of incidence of the beam 411 on the surface 406. In one embodiment, the field of view 410 is defined by the refracted beam 412 between the surface breaks of the incident beam 411 on the first surface 406. In one embodiment, the field of view 410 is larger than the field of view 310 in the polygonal reflector 304. In one embodiment, the field of view 410 is approximately 90 degrees (e.g., a polygonal deflector 404 made of a high-index material, such as silicon) or approximately 50 degrees (e.g., a polygonal deflector 404 made of a non-singular material), compared to a field of view 310 that is less than or approximately 90 degrees. In one embodiment, the width of the polygonal deflector 404 (e.g., defined as the distance between opposing faces 406) is approximately the same as the width of the polygonal reflector 304 (e.g., defined as the distance between opposing faces 306), and the width of each face 406 is approximately the same as the width of each face 306. Thus, the space saving of the assembly 400 compared to the assembly 300 can be attributed to the fact that the assembly 400 does not require external components of the assembly 300 relative to the polygonal deflector 404 (e.g., collimators to guide the incident beam 311). In one embodiment, the polygonal deflector 404 has a width of approximately 70 mm (e.g., measured between faces 406 on opposite sides of the deflector 404) and a length of approximately 44 mm along each face 406. In one embodiment, the polygonal reflector 304 has similar dimensions to the polygonal deflector 404, but has an additional collimator (e.g., to guide the incident beam 311) measuring approximately 50 mm from and spaced approximately 25 mm from the polygonal reflector 304. Thus, the front region length of the polygonal deflector 404 is approximately 70 mm compared to the approximately 140 mm of the polygonal reflector 304. In one embodiment, the incident beam 411 is continuously refracted across the field of view 410 by each face 406 as the polygonal deflector 404 is rotated by the motor 232. In one embodiment, the duty cycle of the polygonal deflector 404 is greater than 50% and / or greater than approximately 70% and / or approximately 80%. The duty cycle can be based on the ratio of a first time to a second time, with the first time based on the refraction of the incident beam 411 and the second time based on the rotation of the polygon deflector 404 and the shaping of the incident beam 411.

[0092] Figure 5A This is a schematic diagram showing an example of a cross-sectional side view of an assembly 500 including a polygonal deflector 501 rotated by a motor 534 to refract an incident light beam 580 from inside the deflector 501 532. Figure 5B It is shown Figure 5A This is a schematic diagram of an example of a cross-sectional top view of a polygonal deflector 501. In one embodiment, the polygonal deflector 501 includes a plurality of faces 506. In one embodiment, the polygonal deflector 501 is made of a material that is transmissive at the wavelength of the light beam 580 or has high transmissivity (e.g., over 90%). Although Figures 5A to 5B A hexagonal deflector (e.g., six sides) is depicted, but various implementations are not limited to hexagonal deflectors and may include any polygonal deflector having any number of faces, and for example, it does not have to be a regular polygon with faces 506 having equal angles and equal widths, but may be an irregular polygon with faces 506 having unequal angles or unequal widths.

[0093] The polygonal deflector 501 can be rotatably coupled to the motor 534. In one embodiment, the motor 534 rotates the polygonal deflector 501 about a rotation axis 540. In one embodiment, the rotation axis 540 is orthogonal to a first plane 541. Figure 5B (in the plane), where the polygon deflector 501 rotates at a rotational speed 502. Although Figures 5A to 5B The rotational speed 502 is described as clockwise, but it can be counterclockwise. In one embodiment, the magnitude of the rotational speed is from about 100 revolutions per minute (rpm) to about 1000 rpm and / or from about 10 rpm to about 10,000 rpm. In some embodiments, the magnitude of the rotational speed can be an order of magnitude larger than the range disclosed herein. In one embodiment, the motor 534 is a brushless DC (BLDC) motor including a plurality of bearings 520a, 520b rotatably coupled to the inner surface 536 of a polygonal deflector 501 defining an interior 532. The motor 534 may include a rotor 522 actuated by coils 524 to rotate the polygonal deflector 501 about a rotation axis 540. The motor 534 may include a stator 526 partially positioned within the interior 532 of the polygonal deflector 501 and defining a cavity 530 in which optical components are positioned to deflect an incident beam 580 on a surface 506. The stator can output an electromagnetic field to drive coil 524, thereby actuating rotor 522. In one embodiment, motor 534 is made of Nidec. BLDC motors manufactured by Braintree MA Corporation.

[0094] In one embodiment, one or more optical components are positioned within the interior 532 of a polygonal deflector 501 to redirect an incident light beam 580 on surface 506. In one embodiment, the optical components include a lens assembly 505 comprising one or more lenses and / or a pair of mirrors 528a, 528b. In one embodiment, the lens assembly 505 is a freeform toric single lens.

[0095] Figure 5G It is shown Figure 5A This is a schematic diagram of an example cross-sectional view of a single toric lens 505' used in the assembly 500. In one embodiment, the toric lens 505' is used in place of the lens assembly 505. In one embodiment, the toric lens 505' is selected because it features some characteristics of a cylindrical lens and other characteristics of a spherical lens, and / or is a hybrid lens with an annular shape, the annular shape being an optical combination of the first and second lenses of the lens assembly 505. In one embodiment, the software instructions of module 270 may include one or more instructions determining one or more parameter values ​​of the toric lens 505' equivalent to those of the lens assembly 505. In one embodiment, the beam 580 is mounted on the focal plane of the lens assembly 505 (e.g., Figure 5A The planar fiber array 529 in the plane 543 transmits to the interior 532.

[0096] Figure 5C This illustrates an embodiment. Figure 5A A schematic diagram of an example side view of the planar fiber array 529 of the assembly 500. In one embodiment, Figure 5C Along and Figure 5A The same plane 543 is cut (e.g., the focal plane of lens assembly 505). In one embodiment, the planar fiber array 529 includes a plurality of fibers 582a, 582b, 582c spaced apart by corresponding lateral spacings 584a, 584b. Although in Figure 5CThe planar fiber array 529 depicts three optical fibers 582, but this is only an example, and more or fewer optical fibers 582 may be provided in the planar fiber array 529. In some embodiments, the lateral spacings 584a, 584b are the same between adjacent fiber pairs. In some embodiments, the lateral spacings 584a, 584b are not the same between adjacent fiber pairs (e.g., the spacing 584a between fibers 582a, 582b is different from the spacing 584b between fibers 582b, 582c). In one embodiment, corresponding beams 580 are emitted from the tip of each fiber 582, thus, multiple beams 580 are emitted from the tips of the fibers 582 within an interior 532 (e.g., cavity 530 of stator 526). In one example embodiment, the planar fiber array 529 is a fixed-pitch fiber array and a planar optical circuit (PLC) connection, manufactured by Zhongshan Meisu Technology Co., Ltd. in Zhongshan City, Guangdong Province, China.

[0097] like Figure 5A As depicted, multiple beams 580 emitted from a planar fiber array 529 can be reflected by a first reflector 528a to a second reflector 528b, which in turn reflects the multiple beams 580 to a lens assembly 505. In one embodiment, reflectors 528a and 528b are orthogonally angled to each other (e.g., 90 degrees, or in the range from about 70 degrees to about 110 degrees), such that the beams 580 reflected by reflector 528b are oriented in a direction about 180 degrees from the direction of the beams 580 incident on reflector 528a. In one embodiment, the second reflector 528b has a longer reflective surface than the first reflector 528a because the beams 580 cover a wider angular extension at the second reflector 528b than at the first reflector 528a. In an example embodiment, reflector 528 is from Edmunds, Barrington, New Jersey, USA. Manufactured by Optics.

[0098] Figure 5D This illustrates an embodiment. Figure 5A A schematic diagram of an example side view of the lens assembly 505 of the assembly 500. In one embodiment, Figure 5D along Figure 5B The plane 541 is intercepted (e.g., orthogonal to). Figure 5A (plane 543). In one embodiment, the lens assembly 505 includes a first lens 582 that collimates a diverging light beam 580 reflected from the second mirror 528b to the first lens 582. In one embodiment, the first lens 582 is an aspherical lens whose focal length is selected such that the diverging light beam 580 from the second mirror 528b is collimated by the aspherical lens. In one embodiment, the focal length of the aspherical lens extends beyond the second mirror 528b.

[0099] like Figure 5D As depicted, the collimated beam 580' from the first lens 582 can be redirected by the second lens 584. In one embodiment, the second lens 584 is a cylindrical lens that converges the beam based on the focal length of a cylindrical lens. In one embodiment, the converged beam 580'' from the second lens 584 is refracted by the inner surface 536 of a polygonal deflector 501 defining the interior 532, such that the beam 580''' is collimated within the polygonal deflector 501 and incident on the surface 506. In an example embodiment, the focal length of the first lens 582 is about 40-50 mm and / or about 20-60 mm, and a beam 580' with a diameter of about 8-10 mm and / or about 6-12 mm is generated using standard optical fiber with a mode field diameter (MFD) of about 10 μm and / or about 6-14 μm MFD. In one embodiment, the beam spacing 584a, 584b in the fiber array 529 will be an increment or multiple of approximately 127 μm, producing a total facing angle extension 560 of approximately 1-4 degrees. In one embodiment, the curvature of the cylindrical lens is the same as the curvature of the inner surface 536 and / or the transition of the refractive index from the cylindrical lens to air is opposite to the transition of the refractive index from air across the inner surface 536 to the polygonal deflector 501. In one embodiment, the refractive index of the second lens 584 is approximately 1.7 or in the range of approximately 1.3 to approximately 1.8, and the refractive index of the polygonal deflector 501 is approximately 1.7 in the range of approximately 1.3 to approximately 1.8, and the curvature of the cylindrical lens and the inner surface 536 is a radius of approximately 25.4 mm and / or in the range of approximately 20 mm to approximately 30 mm and / or in the range of approximately 15 mm to approximately 40 mm. The beam 580''' incident on surface 506a Figure 5B The description in the middle, Figure 5B Plane 541 or Figure 5D The beam of light in the plane is 580'''.

[0100] Figure 5E This shows the two rotational positions 550a and 550b. Figure 5B A schematic diagram of an example of a polygonal deflector 501. In one embodiment, a collimated beam 580''' incident from the interior 532 onto surface 506a is refracted by surface 506a according to Snell's law:

[0101] (5)

[0102] Where n1 is the refractive index of the polygonal deflector 501, θ1 is the angle of incidence of the beam 580''' on surface 506a relative to the normal of surface 506a (interior), n2 is the refractive index of the medium surrounding the polygonal deflector 501 that refracts the beam 512 (e.g., air = 1), and θ2 is the angle of refraction of the beam 512a relative to the normal of surface 506a (exterior). The angle of refraction can be measured as the angle 552a relative to the axis 544 orthogonal to the axis of rotation 542. Figure 5E As depicted, multiple beams 512a are refracted at an angle 552a (relative to axis 544). As the polygonal deflector 501 rotates about axis 542 from a first rotational position 550a to a second rotational position 550b, the incident beam 580''' can be refracted by one side of surface 506a (e.g., refracted beam 512a at angle 552a) to the opposite side of surface 506a relative to axis 544 (e.g., refracted beam 512b at angle 552b), thereby defining the field of view of the refracted beam 512. In one embodiment, the field of view 510 is about 50 degrees (e.g., where the refractive index of the polygonal deflector 501 is about 1.6) and about 90 degrees (e.g., where the refractive index is higher for high refractive index materials, such as silicon).

[0103] Figure 5F It is shown Figure 5A A schematic diagram of an example of a partial cross-sectional side view of a polygon deflector 501. In one embodiment, Figure 5F exist Figure 5A Within plane 543. In one embodiment, the incident beam 580''' is depicted in plane 543, showing the angular extension 560 of the incident beam 580'''. In one embodiment, the angular extension 560 is related to the lateral spacing 584 of the fibers 582 of the planar fiber array 529 by the following equation:

[0104] (6)

[0105] Where y is the distance of the optical fiber 582 outside the focal plane of the lens assembly 505, for example, the distance of the optical fiber 582 outside the plane 543, and the focal length is the focal length of the lens 582 of the lens assembly 505. In some embodiments, the surface 506 forms a non-orthogonal angle 574 with the top or bottom of the polygon deflector 501. In one embodiment, the non-orthogonal angle 574 is any angle other than 90 degrees, and / or an angle in the range from about 75 degrees to about 105 degrees, and / or an angle in the range from about 60 degrees to about 120 degrees. Additionally, although... Figure 5F The non-orthogonal angle 574 is less than 90 degrees, but the non-orthogonal angle 574 can be greater than 90 degrees, for example, for... Figure 5AThe non-orthogonal angle 574 of the mid-surface 506b. Angle 574 may be orthogonal and / or approximately 90 degrees for some or all faces 506. Angle 574 may be non-orthogonal for each face 506, but varies for one or more faces; for example, less than approximately 90 degrees for one or more faces 506, but greater than approximately 90 degrees for one or more faces 506. The advantage of arranging one or more faces 506 with an angle 574 less than 90 degrees and one or more faces 506 with an angle 574 greater than 90 degrees is that plane 543 ( Figure 5F The refracted beam in the plane 512 can alternate between above the horizontal axis 544 (for a surface 506 with an angle 574 of less than 90 degrees) and below the horizontal axis 544 (for a surface 506 with an angle 574 of greater than 90 degrees). This allows the beam 512 to be scanned at multiple distances within the plane 543, for example, to capture and return beam data from objects within these multiple distances.

[0106] In one embodiment, the incident beam 580''' on surface 506 has an angular extension 560, which widens to a larger angular extension 562 after being refracted by surface 506. In one embodiment, the angular extension 562 is widened based on the ratio of the refractive index of polygonal deflector 501 (e.g., n=1.5) to the refractive index of the medium surrounding polygonal deflector 501 (e.g., air=1). In an example embodiment, if each beam 580''' has an angular spacing of approximately 1 degree incident on surface 506, then each refracted beam 512 has an angular spacing of approximately 1.5 degrees, for example, the product of the angular spacing of the beams 580''' in the polygonal deflector and the refractive index ratio.

[0107] In one embodiment, in addition to widening the angular spread, the net direction of the beam 512 in plane 543 is changed by refraction at surface 506. In one embodiment, based on Snell's law in Equation 5, the centerline 570 of the incident beam 580''' on surface 506 is refracted by surface 506 to become the centerline 572 of the refracted beam 512. Thus, in addition to the increased angular spread 562 of the refracted beam 512, surface 506 can change the direction of the centerline 572 of the refracted beam 512 relative to the centerline 570 of the incident beam 580''. In one embodiment, the change in angular spread 560 is approximately 50%, for example, from an angular spread 560 of approximately 1 degree between beams 580 to an angular spread 562 of approximately 1.5 degrees between beams 580. In one embodiment, the change in centerline 572 relative to centerline 570 is approximately +5, +10, -5, or -10 degrees.

[0108] 5. Vehicle Control Overview

[0109] In some implementations, vehicle control is based at least in part on data received from a high-resolution Doppler LIDAR system installed on the vehicle.

[0110] Figure 2E This is a block diagram illustrating an example system 234 including at least one high-resolution Doppler LIDAR system 236 mounted on a vehicle 238 according to an embodiment. In one embodiment, the LIDAR system 236 is similar to one of the LIDAR systems 200. The vehicle has a center of mass indicated by star 242 and travels in the forward direction given by arrow 244. In some embodiments, the vehicle 238 includes components such as steering or braking systems (not shown) that operate in response to signals from a processor, such as a vehicle control module 272 of processing system 250. In some embodiments, the vehicle has an onboard processor 246, such as... Figure 8 The chipset depicted. In some embodiments, the onboard processor 246 communicates wirelessly with a remote processor, such as... Figure 7 As depicted in [the text]. In one embodiment, the processing system 250 of the LIDAR system is communicatively coupled to the onboard processor 246, or the processing system 250 of the LIDAR is used to perform operations of the onboard processor 246, such that the vehicle control module 272 causes the processing system 250 to transmit one or more signals to the vehicle's steering or braking system, thereby controlling the vehicle's direction and speed (e.g., to perform collision avoidance regarding one or more objects detected using information received from the LIDAR system 236). The vehicle control module 272 can control the operation of the processing system 250 using at least one of distance data or speed data (including direction data) determined using the LIDAR system 236. High-resolution Doppler LIDAR uses a scanning beam 252 that sweeps from one side to the other, represented by a future beam 253, through an azimuth field of view 254, and through the vertical angle of the spot of light illuminating the area around the vehicle 238. In some embodiments, the field of view is a 360-degree azimuth. In some embodiments, the scanning optics 218, including the oscillating scanning element 226 and / or the unidirectional scanning element 228, can be used to scan the beam via the azimuth field of view 254 or via the vertical angle. In one embodiment, the tilt angle field of view ranges from about +10 degrees to about -10 degrees or a subset thereof. In one embodiment, the maximum design distance over the field of view 254 is about 200 meters or in the range from about 150 meters to about 300 meters.

[0111] In some embodiments, the vehicle includes auxiliary sensors (not shown), such as a GPS sensor, odometer, tachometer, temperature sensor, vacuum sensor, voltage or current sensor, etc. In some embodiments, a gyroscope 256 is included to provide rotation information.

[0112] 6. Optimization methods for scanning modes in coherent LiDAR systems

[0113] Figure 6 This is a flowchart illustrating an example method 600 for optimizing the scanning pattern of a LiDAR system. In one embodiment, method 600 optimizes the scanning pattern of a beam in a first direction between a first angle and a second angle based on a desired waveform having a linear slope. In some embodiments, method 600 is used to optimize the scanning pattern of a LiDAR system mounted on an autonomous vehicle. Although in Figure 6 For illustrative purposes, the steps are described as a whole in a particular order, but one or more steps or parts thereof may be performed in a different order, or overlap in time, be sequential or parallel, or be omitted, or one or more additional steps may be added, or the method may be changed in some combination.

[0114] In step 601, the polygon deflector 404 is rotated about a first axis by a motor. In one embodiment, in step 601, the polygon deflector 501 rotates about axis 540 with motor 534. In one embodiment, in step 601, one or more signals are transmitted to motors 232, 534 to rotate the polygon deflectors 404, 501, wherein the signals include data indicating one or more values ​​of parameters of rotation (e.g., the value of rotation speed, the direction of rotation speed, the duration of rotation, etc.).

[0115] In step 603, one or more beams are emitted within the interior 432 of the polygon deflector 404. In one embodiment, in step 603, a plurality of beams 580 are emitted from a planar fiber array 529 within the interior 532 of the polygon deflector 501. In one embodiment, in step 603, a light source (e.g., a laser source) is positioned within the interior 532 to emit beams from within the interior 532.

[0116] In step 605, one or more beams are shaped within interior 432 using one or more optical components 405 such that the beams are collimated and incident on surface 406 from interior 432 of polygon deflector 404. In one embodiment, in step 605, multiple beams 580 from planar fiber array 529 are reflected by a pair of mirrors 528a, 528b to lens assembly 505, which includes a first lens 582 positioned within interior 532.

[0117] In step 607, the multiple beams 580 from the reflectors 528a and 528b in step 605 are collimated into beam 580' by the first lens 582. In one embodiment, the first lens 582 is an aspherical lens.

[0118] In step 609, the plurality of beams 580' from the first lens 582 in step 607 are redirected by the second lens 584. In one embodiment, the second lens 584 is a positive cylindrical lens, and the beams 580' are converged into a converging beam 580'' incident on the inner surface 536 of the polygon deflector 501.

[0119] In step 611, the converging beam 580'' from step 609 is collimated by the inner surface 536 of the polygon deflector 501, such that the collimated beam 580''' is emitted into the polygon deflector 501 and incident on the surface 506.

[0120] In step 613, the collimated beam 580''' incident on surface 506 is refracted as beam 512 by surface 506 into a first plane 541 orthogonal to the axis of rotation 542, from a first angle to a second angle defining a field of view 510 within plane 541. In one embodiment, the field of view 510 is defined by the collimated beam 580''' passing from one side of surface 506 to the opposite side, and ends when the collimated beam 580''' crosses an interruption in surface 506. In one embodiment, once the collimated beam 580''' moves to an adjacent surface 506, the refracted beam 512 is rescanned through the field of view 510 within plane 541. In another embodiment, in step 613, the collimated beam 580''' incident on surface 506 is refracted as beam 512 into a second plane 543 orthogonal to the first plane 541. In one embodiment, the refraction of beam 580''' in the second plane 543 involves an increase in the angular spread 562 of beam 512, and / or the refraction of the centerline of beam 512 and / or the rotation of beam 512 within plane 543 based on the rotation of polygon deflector 404. Polygon deflector 404 may have a duty cycle greater than 50%, wherein the duty cycle is based on the ratio of a first time to a second time, the first time being based on the refraction step and the second time being based on the rotation and shaping steps. The duty cycle may be greater than 70%.

[0121] 7. LiDAR systems using multiple scanners

[0122] The systems and methods according to this disclosure can use multiple scanners, enabling the output beam to be steered in a greater number of directions, such as to output a beam spanning more elevation angles. For example, a LIDAR system may include two concentric polygon scanners with faces having varying tilt angles. Optical components may output a collimated beam refracted by the first polygon scanner to a second polygon scanner, which in turn refracts the beam to output a beam from the LIDAR system. The varying tilt angles of the polygon scanners (which may rotate relative to each other and the optical components) allow for different elevation angles for the output beam. This can increase the amount of signal information received based on the output beam over a given time period while maintaining the compact form factor of the LIDAR system, such as determining the distance and velocity of an object, which can be determined from the returning beam from the object reflecting or scattering the output beam, thereby improving the signal-to-noise ratio.

[0123] Figure 7 This is a schematic diagram of a LIDAR system 700. The LIDAR system 700 and its components can incorporate features of various devices and systems described herein, such as LIDAR system 200, assemblies 300, 400, 500, and polygon deflectors 404, 501, and vehicle control module 272. For example, the LIDAR system 700 can operate with or include components of the LIDAR system 200, such as scanning optics 218 or detector array 230, to determine at least one of the distance or velocity of an object using a returning beam from the object, and to control the operation of a vehicle in response to at least one of the distance or velocity.

[0124] The LIDAR system 700 includes a first polygon scanner 704. The first polygon scanner 704 may include a first face 708 about a first axis of rotation 702, and a first body 706 extending outward from the first face 708 relative to the first axis of rotation 702. For example, as... Figure 8 As depicted, the first polygonal body 704 may include five first faces 708a, 708b, 708c, 708d, and 708e. The first faces 708 may form a polygonal shape about a first axis of rotation 702, such that each first face 708 is connected to two adjacent first faces 708. The first faces 708 may refract the received light beam, thereby changing the angle of the light from the inlet, air-surface interface (e.g., inward) to the outlet side of the first face 708 (e.g., outward).

[0125] The number of first faces 708 can be determined based on various factors, such as the number of signal lines to be detected, the field of view of the first faces 708, the number of transitions between the first faces 708, and the size of the first polygon scanner 704. For example, as the number of first faces 708 increases, more signal lines can be detected (e.g., more elevation angles can be used to output the beam), the size of the first polygon scanner 704 can be increased, and the field of view of the first faces 708 can be decreased (e.g., the first faces 708 can have a field of view equal to 360 / face number, making...). Figure 8 The five first faces 708 depicted can each have a field of view of 72 degrees, while the faces of a polygonal scanner with three faces can each have a field of view of 120 degrees, and the number of transitions (e.g., transitions between adjacent first faces 708) can be increased. Transitions can reduce the surface area of ​​the first polygonal scanner 704 that can be effectively used for output beams. The number of first faces 708 can be greater than or equal to three and less than or equal to ten.

[0126] The first polygon scanner 704 may define a first maximum thickness 712 from the innermost part of the first polygon scanner 704 (e.g., closest to the first rotation axis 702) to the outermost part (e.g., furthest from the first rotation axis 702). The first maximum thickness 712 may be greater than or equal to 3 mm and less than or equal to 10 mm.

[0127] Further reference Figure 7 The LIDAR system 700 may include a second polygon scanner 720, which may be positioned or located outward from the first polygon scanner 704 relative to a first axis of rotation 702 (i.e., the face of the second polygon scanner is positioned outward from the face of the first polygon scanner). The second polygon scanner 720 may incorporate features of the first polygon scanner 704. A bearing 716 may be positioned between the first polygon scanner 704 and the second polygon scanner 720, thereby allowing the first polygon scanner 704 to rotate over the second polygon scanner 720. The bearing 716 may be a refractive index fluid bearing.

[0128] The second polygon scanner 720 may include a second face 724 about a second axis of rotation. The second axis of rotation may be the same as (e.g., coincident with) the first axis of rotation 702, or it may be parallel to (e.g., parallel and spaced apart from) the first axis of rotation 702. Figure 8As depicted, the second polygon scanner 720 may include five second faces 724a, 724b, 724c, 724d, and 724e. The second faces 724 may be formed into a polygonal shape about a second axis of rotation, such that each second face 724 is connected to two adjacent second faces 724. The second faces 724 may refract the received light beam to change the angle of the light from the entrance side (e.g., inward) of the second face 724 to the exit side, the surface-to-air interface (e.g., outward).

[0129] The number of second faces 724 can be determined based on various factors, such as the number of signal lines to be detected, the field of view of the second faces 724, the number of transitions between the second faces 724, and the size of the second polygon scanner 720. For example, as the number of second faces 724 increases, more signal lines can be detected, the size of the second polygon scanner 720 can be increased, the field of view of the second faces 724 can be decreased, and the number of transitions can be increased. The number of second faces 724a can be greater than or equal to three and less than or equal to ten.

[0130] The first surface 708 and the second surface 724 can have varying angles (e.g., tilt angles) relative to their respective first and second rotation axes, and these varying angles can be used to control the elevation angle of the light output from the second surface 724. For example, as Figure 9 As depicted, a specific first face 708 of the first polygon scanner 704 can define a first angle 904 of inward surface 908 relative to the first axis of rotation 702, and a specific second face 724 of the second polygon scanner 720 can define an outward surface 916 relative to the second axis of rotation (e.g., ...). Figure 9 The second angle 912 (which coincides with the first axis of rotation 702) is depicted in the figure.

[0131] At least two of the first faces 708 can define first angles 904 that are different from each other. At least two second faces 724 can define second angles 912 that are different from each other. The order of angles 904, 912 (e.g., faces 708, 724 defining specific angles 904, 912) can be varied, such as to balance the mass of corresponding polygon scanners 704, 720 relative to corresponding first and second rotation axes. Angles 904, 912 can be greater than or equal to -12 degrees and less than or equal to 12 degrees. Angles 904, 912 can be greater than or equal to -8 degrees and less than or equal to 8 degrees (in... Figure 9 In the reference frame depicted, a negative angle can indicate that the lower edge of a particular first surface 708 or a particular second surface 724 extends outward from the upper edge of the particular first surface 708 or the particular second surface 724. For example, for Figure 9 The specific first face 708 and specific second face 724 depicted in the figure, the first angle 904 can be negative four degrees, and the second angle 912 can be six degrees.

[0132] Further reference Figure 7 The first polygon scanner 704 and the second polygon scanner 720 can be made of a material with relatively high parameters in at least one of refractive index, transparency (e.g., the wavelength of light to be refracted and output by the polygon scanners 704 and 720, such as around 1500 nm), or optical quality (e.g., low scattering). The materials of the polygon scanners 704 and 720 can be selected such that they have the same refractive index. The transparency of the polygon scanners 704 and 720 allows them to operate as transmissive polygons. The polygon scanners 704 and 720 can be made of polymeric materials. They can be made of materials such as polystyrene, REXOLITE manufactured by C-Lec Plastics, or ZEONEX manufactured by ZEON.

[0133] The LIDAR system 700 may include an optical component 728 (e.g., an optical assembly) that outputs a first beam 732 to a first polygon scanner 704. The optical component 728 may collimate the first beam 732. The optical component 728 may use a laser to output the first beam 732. The optical component 728 may have a compact form factor to reduce the size of the LIDAR system 700. The optical component 728 may include one or more lenses or mirrors that can shape the first beam 732 and control its direction. At least a portion of the optical component 728 may be positioned such that the laser is emitted within the interior 710 of the first polygon scanner 704.

[0134] A first polygon scanner 704 (e.g., a specific first face 708 of the first polygon scanner 704) can refract a first beam 732 to output a second beam 736 incident on a specific second face 724 of a second polygon scanner 720. A second polygon scanner 720 (e.g., a specific second face 724 of the second polygon scanner 720) can refract the second beam 736 to output a third beam 740.

[0135] Optical component 728 may include a light source 744, such as a laser, which outputs light to at least one reflector 748. For example, as Figure 7 As depicted, at least one reflector 748 may include a first reflector 748 and a second reflector 748. At least one reflector 748 may reflect light to a lens 752, and the lens 752 may output a first beam 732.

[0136] The LIDAR system 700 may include at least one motor 756 that rotates a first polygon scanner 704 and a second polygon scanner 720 relative to corresponding first and second rotation axes. The at least one motor 756 may incorporate features of motor 534. The at least one motor 756 may be coupled to the first polygon scanner 704 and the second polygon scanner 720. The at least one motor 756 may include a first motor 756a coupled to the first polygon scanner 704 and a second motor 756b coupled to the second polygon scanner 720. The at least one motor 756 may include a single motor coupled to each of the first polygon scanner 704 and the second polygon scanner 720, the single motor driving the polygon scanners 704 and 720 using various gears or mechanical linkages (not shown). The at least one motor 756 may rotate the polygon scanners 704 and 720 about corresponding first and second rotation axes in the same or different directions (including opposite directions where the first and second rotation axes are the same or parallel).

[0137] At least one motor 756 can rotate a first polygon scanner 704 at a first rotation frequency ω1 and a second polygon scanner 720 at a second rotation frequency ω2. The rotation frequencies ω1 and ω2 can be used to control which first surface 708 refracts the first beam 732 to output the second beam 736, and which second surface 724 refracts the second beam 736 to output the third beam 740. Therefore, the rotation frequencies ω1 and ω2 can be used to control the azimuth angle (based on the angle at which beams 732 and 736 strike the corresponding first surface 708 and second surface 724) and elevation angle (based on angles 904 and 912) of the third beam 740. The rotation frequencies ω1 and ω2 can be controlled such that one of the first polygon scanner 704 or the second polygon scanner 720 has a relatively large turning angle, while the other has a relatively small turning angle (e.g., coarse angle control with one of scanners 704 and 720, and fine angle control with the other). Second, the outward polygon scanner 720 can be controlled to turn at a relatively large angle, which allows the first inward polygon scanner 704 to be relatively small and reduces the space used for the first polygon scanner 704.

[0138] The LIDAR system 700 may include at least one position sensor 760. The position sensor 760 can detect the position (e.g., angular position) of at least one of the first polygon scanner 704 or the second polygon scanner 720. For example, the position sensor 760 may be coupled to or be part of at least one motor 756, such as to detect the position of at least one of the first polygon scanner 704 or the second polygon scanner 720 using the position of at least one motor 756 coupled to at least one of the first polygon scanner 704 or the second polygon scanner 720. The position sensor 760 can output at least one position signal with respect to the position of at least one of the first polygon scanner 704 or the second polygon scanner 720, and the position signal can be used to control the corresponding rotation frequencies ω1, ω2.

[0139] Figure 10 The image depicts the passage of the first beam 732 and the second beam 736 through a path such as... Figure 7 The diagram 1000 shows the azimuth angle θ and elevation angle φ of the path of the third beam 740 of the two first faces 708 (faces 708a and 708b) and five second faces 724 (faces 724a, 724b, 724c, 724d, and 724e) of the polygon scanners 704 and 720. Rotation of the first polygon scanner 704 and the second polygon scanner 720 causes various combinations 1004 of the first faces 708 and 724 to interact with the light output from the optical component 728, so as to output the third beam 740 (e.g., a combination of a specific first face 708 refracting a first beam 732 and a specific second face 724 refracting a second beam 736 corresponding to the first beam 732 refracted by the specific first face 708). The combinations 1004 of the first faces 708 and 724 can cause various azimuth angles θ and elevation angles φ of the third beam 740. Combination 1004 can be composed of discrete azimuth and elevation angles, and can vary within the range of azimuth angles.

[0140] Figure 11 A method 1100 for operating a LiDAR system is described. Method 1100 can be performed using various devices and systems described herein, including but not limited to LiDAR system 700.

[0141] At 1105, the first polygon scanner rotates about a first rotation axis at a first rotation frequency. The first polygon scanner may include a plurality of first faces, which may be arranged at various tilt angles relative to the first rotation axis. The first polygon scanner may be rotated by at least one motor coupled to the first polygon scanner.

[0142] At 1110, the second polygon scanner rotates about a second rotation axis at a second rotation frequency, the second rotation axis being alignable with the first rotation axis. The second polygon scanner can extend outward from the first polygon scanner. The second polygon scanner may include a plurality of second faces, which can be arranged at various tilt angles relative to the second rotation axis. The second polygon scanner can be rotated by at least one motor coupled to the second polygon scanner.

[0143] At 1115, the first beam is emitted from inside the first polygon scanner onto a specific first face among a plurality of first faces. The first beam may be emitted by an optical component that outputs the first beam as a collimated beam. For example, the optical component may include a laser source and may include various mirrors and lenses that can guide and shape the first beam onto the specific first face.

[0144] A specific first surface can refract a first light beam (e.g., based on the refractive index of the first polygon scanner relative to the air inside the first polygon scanner), thereby outputting a second light beam to a specific second surface of the second polygon scanner. A specific second surface can refract the second light beam (e.g., based on the refractive index of the second polygon scanner relative to the air outside the second polygon scanner), thereby outputting a third light beam. The azimuth angle of the third light beam can be controlled based on the rotational position of the polygon scanner relative to the rotation axis and the direction of the first light beam. The elevation angle of the third light beam can be controlled based on the rotational position of the polygon scanner relative to the rotation axis and the direction of the first light beam, because the elevation angle can be controlled using the tilt angles of the specific first and specific second surfaces.

[0145] At 1120, the fourth beam is received. The fourth beam can be received by a detector array. The fourth beam can be generated by reflection or other scattering of the third beam by an object. For example, the object can be a vehicle, pedestrian, or bicycle that causes the output of the fourth beam in response to the third beam.

[0146] At 1125, the fourth beam is used to determine at least one of the object's distance or the object's velocity. For example, a detector array can generate a signal representing the fourth beam, and this signal can be processed to determine at least one of the distance or velocity.

[0147] In 1130, the vehicle (e.g., an autonomous vehicle that can operate fully or partially autonomously (i.e., without human interaction)) is controlled in response to at least one of distance or speed. For example, the vehicle's steering or braking system can be controlled to control at least one of the vehicle's direction or speed (e.g., to perform collision avoidance with respect to objects).

[0148] 8. Overview of Computing Hardware

[0149] Figure 12This is a block diagram illustrating a computer system 1200 that can be used to perform the various operations described herein. The computer system 1200 includes a communication mechanism, such as a bus 1210, for transmitting information between other internal and external components of the computer system 1200. Information is represented as a physical signal of a measurable phenomenon, typically voltage, but in other embodiments includes phenomena such as magnetism, electromagnetism, pressure, chemistry, molecular atoms, and quantum interactions. For example, a north-south magnetic field, or zero and non-zero voltage, represents two states (0, 1) of a binary digit (bit). Other phenomena may represent numbers with higher cardinality. A superposition of multiple simultaneous quantum states prior to measurement represents a qubit. A sequence of one or more digits constitutes digital data used to represent numbers or codes for characters. In some embodiments, information called analog data is represented by a near-continuum of measurable values ​​within a specific range. The computer system 1200, or a portion thereof, constitutes means for performing one or more steps of one or more methods described herein.

[0150] A sequence of binary digits constitutes digital data used to represent numbers or codes. Bus 1210 includes a plurality of parallel information conductors to facilitate the rapid transfer of information between devices coupled to bus 1210. One or more processors 1202 are coupled to bus 1210 for processing the information. Processor 1202 performs a set of operations on the information. This set of operations includes bringing information in from bus 1210 and placing information on bus 1210. This set of operations typically also includes comparing two or more information units, moving the positions of information units, and combining two or more information units, such as by addition or multiplication. The sequence of operations to be performed by processor 1202 constitutes computer instructions.

[0151] Computer system 1200 also includes memory 1204 coupled to bus 1210. Memory 1204, such as random access memory (RAM) or other dynamic storage devices, stores information including computer instructions. Dynamic memory allows information stored therein to be changed by computer system 1200. RAM allows information units stored at locations referred to as memory addresses to be stored and retrieved independently of information at adjacent addresses. Memory 1204 is also used by processor 1202 to store temporary values ​​during the execution of computer instructions. Computer system 1200 also includes read-only memory (ROM) 1206 or other static storage devices coupled to bus 1210 to store static information, including instructions, that is not changed by computer system 1200. Also coupled to bus 1210 is a non-volatile storage device 1208, such as a disk or optical disk, to store information, including instructions, that persists even when computer system 1200 is turned off or otherwise powered down.

[0152] Information, including instructions, is provided from external input devices 1212 to the bus 1210 for use by the processor. These external input devices may be, for example, a keyboard containing alphanumeric keys operated by a human user, or sensors. Sensors detect conditions in their vicinity and convert those detections into signals compatible with signals used to represent information in the computer system 1200. Other external devices coupled to the bus 1210, primarily for human interaction, include: a display device 1214, such as a cathode ray tube (CRT) or liquid crystal display (LCD), for displaying images; and a pointing device 1216, such as a mouse, trackball, or arrow keys, for controlling the position of a small cursor image displayed on the display 1214 and issuing commands associated with graphical elements displayed on the display 1214.

[0153] In the illustrated embodiment, special-purpose hardware (such as application-specific integrated circuit (IC) 1220) is coupled to bus 1210. The special-purpose hardware is configured to perform operations that are not performed by processor 1202, sufficiently quickly for its specific purpose. Examples of application-specific ICs include graphics accelerator cards for generating images for display 1214, cryptographic pads for encrypting and decrypting messages sent over a network, speech recognition, and interfaces with specialized external devices (such as robotic arms and medical scanning devices that repeatedly perform complex sequences of operations), which are implemented more efficiently in hardware.

[0154] Computer system 1200 also includes one or more instances of a communication interface 1270 coupled to bus 1210. Communication interface 1270 provides bidirectional communication coupling to various external devices, such as printers, scanners, and external disks, that operate with their own processors. Generally, the coupling is with network link 1278, which is connected to local area network 1280, to which various external devices with their own processors are connected. For example, communication interface 1270 may be a parallel port, a serial port, or a Universal Serial Bus (USB) port on a personal computer. In some embodiments, communication interface 1270 is an Integrated Services Digital Network (ISDN) card, a Digital Subscriber Line (DSL) card, or a telephone modem that provides an information communication connection to a corresponding type of telephone line. In some embodiments, communication interface 1270 is a cable modem that converts signals on bus 1210 into signals for communication connections via coaxial cable or optical signals for communication connections via fiber optic cable. As another example, the communication interface 1270 can be a local area network (LAN) card to provide data communication connectivity to a LAN-compatible network, such as Ethernet. A wireless link can also be implemented. A carrier wave (such as sound waves and electromagnetic waves), including radio, optical, and infrared waves, travels through space without wires or cables. Signals include artificial variations in the amplitude, frequency, phase, polarization, or other physical properties of the carrier wave. For a wireless link, the communication interface 1270 transmits and receives electrical, acoustic, or electromagnetic signals, including infrared and optical signals, which carry information streams, such as digital data.

[0155] The term "computer-readable medium" is used herein to refer to any medium that participates in providing information to processor 1202, including instructions for execution. Such media can take many forms, including but not limited to non-volatile media, volatile media, and transmission media. Non-volatile media include, for example, optical discs or magnetic disks, such as storage device 1208. Volatile media include, for example, dynamic memory 1204. Transmission media include, for example, coaxial cables, copper wires, fiber optic cables, and waves (such as sound waves and electromagnetic waves) that travel through space without wires or cables, including radio, optical, and infrared waves. The term "computer-readable storage medium" is used herein to refer to any medium that participates in providing information to processor 1202, excluding transmission media.

[0156] Common forms of computer-readable media include, for example, floppy disks, flexible disks, hard disks, magnetic tape or any other magnetic media, compact disc ROM (CD-ROM), digital video disc (DVD) or any other optical media, punched cards, paper tape or any other physical media with a perforated pattern, RAM, programmable ROM (PROM), erasable PROM (EPROM), FLASH-EPROM or any other memory chip or cartridge, carrier waves or any other media from which a computer can read. The term "non-transitory computer-readable storage medium" is used herein to refer to any medium involved in providing information to processor 1202, excluding carrier waves and other signals.

[0157] The logic encoded in one or more tangible media includes one or both of processor instructions on a computer-readable storage medium and special-purpose hardware, such as ASIC 1220.

[0158] Network link 1278 typically provides information communication to other devices using or processing the information via one or more networks. For example, network link 1278 may provide a connection to host computer 1282 or to device 1284 operated by an Internet Service Provider (ISP) via local area network 1280. ISP device 1284 then provides data communication services via a public, worldwide packet-switched communication network, now commonly referred to as the Internet 1290. A computer connected to the Internet, referred to as server 1292, provides services in response to information received via the Internet. For example, server 1292 provides information representing video data for display on monitor 1214.

[0159] Computer system 1200 can be used to implement the various techniques described herein. The techniques can be performed by computer system 1200 in response to processor 1202 executing one or more sequences of one or more instructions contained in memory 1204. Such instructions, also known as software and program code, can be read into memory 1204 from another computer-readable medium, such as storage device 1208. Execution of the sequence of instructions contained in memory 1204 causes processor 1202 to perform the steps of the methods described herein. In alternative embodiments, hardware, such as application-specific integrated circuit 1220, can be used instead of or in combination with software to implement the various operations described herein. Thus, the various embodiments are not limited to any particular combination of hardware and software.

[0160] Information carried by signals transmitted over network link 1278 and other networks via communication interface 1270 is sent to and received from computer system 1200. Computer system 1200 can send and receive information, including program code, via network link 1278 and communication interface 1270, through networks 1280, 1290, etc. In an example using Internet 1290, server 1292 transmits application-specific program code requested by a message sent from computer 1200 via Internet 1290, ISP device 1284, local area network 1280, and communication interface 1270. The received code can be executed by processor 1202 upon receipt, or stored in storage device 1208 or other non-volatile memory for later execution, or both. In this way, computer system 1200 can obtain application code in signal form on a carrier wave.

[0161] Various forms of computer-readable media may involve carrying one or more sequences of instructions or data, or both, to processor 1202 for execution. For example, instructions and data may initially be carried on the disk of a remote computer, such as host 1282. The remote computer loads the instructions and data into its dynamic memory and transmits the instructions and data over a telephone line using a modem. A modem local to computer system 1200 receives the instructions and data over the telephone line and uses an infrared transmitter to convert the instructions and data into signals on an infrared carrier wave used as network link 1278. An infrared detector, used as communication interface 1270, receives the instructions and data carried in the infrared signal and places information representing the instructions and data on bus 1210. Bus 1210 carries the information to memory 1204, from which processor 1202 retrieves and executes the instructions using some data transmitted along with them. The instructions and data received in memory 1204 may optionally be stored on storage device 1208, either before or after execution by processor 1202.

[0162] Figure 13 Chipset 1300 is shown. Chipset 1300 is programmed to perform one or more steps of the methods described herein, and includes, for example, regarding... Figure 12 The processor and memory components are incorporated into one or more physical packages (e.g., chips). As an example, a physical package includes an arrangement of one or more materials, components, and / or wires on a structural assembly (e.g., a substrate) to provide one or more features such as physical strength, dimensional retention, and / or limitations on electrical interactions. It is contemplated that, in some embodiments, the chipset may be implemented in a single chip. Chipset 1300 or a portion thereof constitutes means for performing one or more steps of the methods described herein.

[0163] In one implementation, chipset 1300 includes a communication mechanism, such as bus 1301, for transferring information between components of chipset 1300. Processor 1303 has connectivity to bus 1301 to execute instructions and process information stored, for example, in memory 1305. Processor 1303 may include one or more processing cores, each configured to execute independently. Multi-core processors enable multiprocessing within a single physical package. Examples of multi-core processors include two, four, eight, or more processing cores. Alternatively or additionally, processor 1303 may include one or more microprocessors configured in series via bus 1301 to enable independent execution of instructions, pipelining, and multithreading. Processor 1303 may also be accompanied by one or more dedicated components to perform certain processing functions and tasks, such as one or more digital signal processors (DSPs) 1307 or one or more application-specific integrated circuits (ASICs) 1309. DSP 1307 is typically configured to process real-world signals (e.g., sound) in real time independently of processor 1303. Similarly, the ASIC1309 can be configured to perform special-purpose functions that are not easily performed by general-purpose processors. Other special-purpose components that assist in performing the inventive functions described herein include one or more field-programmable gate arrays (FPGAs) (not shown), one or more controllers (not shown), or one or more other special-purpose computer chips.

[0164] Processor 1303 and accompanying components have connectivity to memory 1305 via bus 1301. Memory 1305 includes both dynamic memory (e.g., RAM, disk, writable optical disc, etc.) and static memory (e.g., ROM, CD-ROM, etc.) to store executable instructions that, when executed, perform one or more steps of the methods described herein. Memory 1305 also stores data associated with or generated by the execution of one or more steps of the methods described herein.

[0165] Some illustrative embodiments have now been described, and it is clear that the foregoing, presented as examples, is illustrative and not restrictive. In particular, while many of the examples presented herein relate to specific combinations of methodological behaviors or system elements, those behaviors and elements can be combined in other ways to accomplish the same objective. The behaviors, elements, and features discussed in relation to one embodiment are not intended to exclude similar effects in other embodiments or multiple embodiments.

[0166] The wording and terminology used herein are for descriptive purposes and should not be considered limiting. The terms “comprising,” “including,” “having,” “containing,” “involving,” “characterizing,” and variations thereof, as used herein, are intended to include items listed below, their equivalents, and additional items, as well as alternative implementations comprised of items listed below. In one implementation, the systems and methods described herein consist of one, more than one, or all of the described elements, actions, or components.

[0167] Any reference in this document to a system or method, element, or action referred to in the singular, may also cover embodiments that include multiple such elements, and any reference in this document to any embodiment, element, or action referred to in the plural, may also cover embodiments that include only a single element. References in either the singular or plural form are not intended to limit the currently disclosed system or method, its components, actions, or elements to the singular or plural form. A reference to any action or element based on any information, action, or element may include embodiments in which the action or element is at least in part based on any information, action, or element.

[0168] Any implementation disclosed herein may be combined with any other implementation or embodiment, and references to "an implementation," "some implementations," "one implementation," etc., are not necessarily mutually exclusive and are intended to indicate a particular feature, structure, or characteristic described in conjunction with an implementation that may be included in at least one implementation or embodiment. Such terms used herein do not necessarily refer to the same implementation. Any implementation may be combined inclusively or exclusively with any other implementation in any manner consistent with the aspects and implementations disclosed herein.

[0169] Where reference numerals are appended to technical features in the drawings, detailed descriptions, or any claims, these reference numerals are included to enhance the comprehensibility of the drawings, detailed descriptions, and claims. Therefore, neither the reference numerals nor their absence imposes any limitation on the scope of any claim element.

[0170] The systems and methods described herein may be embodied in other specific forms without departing from their characteristics. Further descriptions of relative parallel, perpendicular, vertical, or other positioning or orientation include variations within + / -10% or + / -10 degrees of purely vertical, parallel, or perpendicular positioning. References to terms such as “approximately,” “about,” “essentially,” or other degrees include variations from a given measurement, unit, or range within + / -10%, unless otherwise expressly indicated. Coupled elements may be directly coupled to each other or electrically, mechanically, or physically coupled to intervening elements. Therefore, the scope of the systems and methods described herein is indicated by the appended claims rather than the foregoing description, and variations within the meaning and scope of the equivalents of the claims are encompassed therein.

[0171] The term "coupling" and its variations include the direct or indirect union of two components. This union can be static (e.g., permanent or fixed) or movable (e.g., removable or releasable). Such union can be achieved by directly connecting or coupling two components together, by coupling two components together using a separate intervening component and any additional intermediate components coupled to each other, or by coupling two components together using an intervening component that integrally forms a single, unified entity with one of the two components. If "coupling" or its variations are modified by an additional term (e.g., direct coupling), the general definition of "coupling" provided above is modified by the simple linguistic meaning of the additional term (e.g., "direct coupling" refers to the union of two components without any separate intervening component), resulting in a narrower definition than the general definition of "coupling" provided above. Such coupling can be mechanical, electrical, or fluid.

[0172] A reference to "or" can be interpreted as inclusive, such that any term described using "or" can refer to a single, more than one, or any one of all the terms described. A reference to "at least one of 'A' and 'B'" can include only 'A', only 'B', or both 'A' and 'B'. Such references used in conjunction with "contains..." or other open terms can include additional items.

[0173] Modifications to the described elements and behaviors, such as changes in the size, dimensions, structure, shape, and proportions of various elements, parameter values, installation arrangements, use of materials, color, and orientation, may occur without substantially departing from the teachings and advantages of the subject matter disclosed herein. For example, an element shown as integrally formed may be constructed from multiple parts or elements, the positions of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. Other substitutions, modifications, alterations, and omissions may also be made in the design, operating conditions, and arrangement of the disclosed elements and operations without departing from the scope of this disclosure.

[0174] References to the location of elements herein (e.g., “top,” “bottom,” “above,” “below”) are used only to describe the orientation of the various elements in the figures. It should be noted that the orientation of the various elements may vary depending on other illustrative embodiments, and such variations are intended to be covered by this disclosure.

Claims

1. A light detection and ranging sensor system, including: A first polygonal scanner, the first polygonal scanner including a plurality of first faces arranged about a rotation axis; A second polygon scanner, the second polygon scanner including a plurality of second faces arranged around the rotation axis, each of the plurality of second faces extending outward from the first polygon scanner relative to the rotation axis; An optical component is configured to output a first light beam to a first polygonal scanner, the first polygonal scanner is configured to refract the first light beam to output a second light beam to a second polygonal scanner, and the second polygonal scanner is configured to refract the second light beam to output a third light beam. as well as At least one motor is configured to rotate the first polygon scanner about the rotation axis and the second polygon scanner about the rotation axis.

2. The optical detection and ranging sensor system according to claim 1, wherein, At least one of the plurality of first faces is oriented at a first angle relative to the axis of rotation, and at least one of the plurality of second faces is oriented at a second angle relative to the axis of rotation, wherein the first angle is different from the second angle.

3. The optical detection and ranging sensor system according to claim 2, wherein, The first angle is between approximately -12 degrees and approximately 12 degrees.

4. The optical detection and ranging sensor system according to claim 2, wherein, The third angle of the third beam corresponds to the first angle and the second angle.

5. The optical detection and ranging sensor system according to claim 1, wherein, The optical component is positioned in the space formed between the plurality of first surfaces through which the rotation axis extends, and the first polygonal scanner is located between the optical component and the second polygonal scanner.

6. The optical detection and ranging sensor system according to claim 1, wherein, The first polygonal scanner includes a first body, and the plurality of first faces are inside the first body facing the axis of rotation.

7. The optical detection and ranging sensor system according to claim 1, wherein, The optical component includes a laser source configured to output the first beam, and at least a portion of the optical component is positioned such that the first beam is emitted inside the first polygonal scanner.

8. The optical detection and ranging sensor system according to claim 1, wherein, The optical components are configured to collimate the first beam.

9. The optical detection and ranging sensor system according to claim 1, wherein, The optical component includes at least one reflector for guiding the first beam to the first polygon scanner.

10. The optical detection and ranging sensor system according to claim 1, wherein, The first refractive index of the first polygonal scanner is the same as the second refractive index of the second polygonal scanner.

11. The optical detection and ranging sensor system according to claim 1, wherein, The plurality of first faces includes three or more and ten first faces.

12. The optical detection and ranging sensor system according to claim 1, wherein, The first polygon scanner and the second polygon scanner each comprise polymeric material.

13. An autonomous vehicle control system, comprising: A light detection and ranging sensor, comprising: A first polygonal scanner, the first polygonal scanner including a plurality of first faces arranged about a rotation axis; A second polygon scanner, the second polygon scanner including a plurality of second faces arranged around the rotation axis, each of the plurality of second faces extending outward from the first polygon scanner relative to the rotation axis; At least one motor, the at least one motor being configured to rotate the first polygon scanner about the rotation axis and the second polygon scanner about the rotation axis; Detector array; and One or more processors, said one or more processors being configured to: The at least one motor is used to rotate the first polygon scanner at a first rotational frequency; The at least one motor is used to rotate the second polygon scanner at a second rotational frequency; The laser source emits a first beam inside the first polygon scanner onto a specific first face among the plurality of first faces, such that the specific first face refracts the first beam to output a second beam incident on a specific second face among the plurality of second faces, and the specific second face refracts the second beam to output a third beam; A signal is received from the detector array based on a fourth beam received at the detector array from an object responding to the third beam; and The distance to the object is determined using the signal received from the detector array.

14. The autonomous vehicle control system according to claim 13, wherein, The second polygon scanner is configured to scan the third beam by rotating at the second rotation frequency.

15. The autonomous vehicle control system according to claim 13, wherein, The plurality of first faces includes three or more and ten or less faces, and the plurality of second faces includes three or more and ten or less faces.

16. An autonomous vehicle, comprising: A light detection and ranging sensor, comprising: A first polygonal scanner includes a plurality of first faces arranged about a rotation axis, wherein a particular first face of the plurality of first faces is configured to refract a first beam to output a second beam. A second polygonal scanner includes a plurality of second faces arranged around the axis of rotation, each of the plurality of second faces extending outward from the first polygonal scanner relative to the axis of rotation, wherein a particular second face of the plurality of second faces is configured to refract the second beam to output a third beam; At least one motor, the at least one motor being configured to rotate the first polygon scanner about the rotation axis and the second polygon scanner about the rotation axis; and One or more processors, said one or more processors being configured to: A fourth beam is used to determine the distance to the object, the fourth beam originating from at least one of the object's reflection or scattering of the third beam; and The distance to the object is used to control the operation of the autonomous vehicle.

17. The autonomous vehicle according to claim 16, wherein, At least one of the plurality of first faces is oriented at a first angle relative to the axis of rotation, and at least one of the plurality of second faces is oriented at a second angle relative to the axis of rotation, wherein the first angle is different from the second angle.

18. The autonomous vehicle according to claim 16, wherein, The first polygonal scanner includes a first body, and the plurality of first faces are inside the first body facing the axis of rotation.

19. The autonomous vehicle according to claim 16, wherein, The plurality of first faces includes three or more faces and ten or less faces.

20. The optical detection and ranging sensor system according to claim 1, wherein, The first polygon scanner and the second polygon scanner are concentric.

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