Lidar sensor system, autonomous vehicle control system and autonomous vehicle

Abstract

The invention provides a LIDAR sensor system, an autonomous vehicle control system and an autonomous vehicle. The LIDAR sensor system includes: a first polygon scanner including a plurality of first faces arranged about a rotation axis; a second polygon scanner including a plurality of second faces arranged about the rotation axis; an optical component configured to output a first light beam to the first polygon scanner, the first polygon scanner configured to refract the first light beam to output a second light beam to the second polygon scanner, the second polygon scanner is configured to refract the second light beam to output a third light beam; and at least one motor configured to rotate the first polygon scanner about the rotation axis and to rotate the second polygon scanner about the rotation axis.

Description

[0001] This application is a divisional application of the application with national application number 202180034633.2 (international application number PCT / US2021 / 032515, international application date May 14, 2021, invention name “LIDAR system”).

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

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

[0004] Optical detection of distance using lasers, often referred to by the mnemonic LIDAR, for Light Detection and Ranging, and sometimes called laser RADAR, is used in a variety of applications - from altimetry to imaging to collision avoidance. LIDAR offers finer-scale distance resolution and smaller beam sizes 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 polygon scanner, a second polygon scanner, and an optic. The first polygon scanner includes a plurality of first facets around an axis of rotation. The second polygon scanner includes a plurality of second facets outward from the plurality of first facets relative to the axis of rotation. The optic is inward from the first polygon scanner relative to the axis of rotation. The optic is configured to output a first light beam to the first polygon scanner. The first polygon scanner is configured to refract the first light beam to output a second light beam to the second polygon scanner. The second polygon scanner is configured to refract the second light beam to output a third light beam.

[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 around a rotation axis. The second polygon scanner includes a plurality of second faces 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 light beam inside the first polygon scanner to a specific first face among the plurality of first faces, so that the specific first face refracts the first light beam to output a second light beam incident on a specific second face among the plurality of second faces, and the specific second face refracts the second light beam to output a third light beam; receive a signal from the detector array based on a fourth light beam from an object received at the detector array in response to the third light beam; 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 polygon scanner, the first polygon scanner including a plurality of first faces around a rotation axis. A specific first face of the plurality of first faces is configured to refract a first light beam to output a second light beam. The LIDAR device includes a second polygon scanner, the second polygon scanner including a plurality of second faces outward from the plurality of first faces relative to the rotation axis. A specific second face of the plurality of second faces is configured to refract the second light beam to output a third light beam. The one or more processors are configured to determine a distance to an object using a fourth light beam received from the object in response to the third light beam, and use the distance to the object to control the operation of the autonomous vehicle.

[0008] Those skilled in the art will appreciate that the summary of the invention is illustrative only and is not intended to be limiting in any way. Any feature described herein may be used with any other feature, and any subset of such features may be used in combination according to various embodiments. Other aspects, inventive features and advantages of the devices and / or processes described herein, as limited only by the claims, will become apparent in the detailed description set forth herein and taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like reference numerals refer to similar elements, and in which:

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

[0011] Figure 1Bis a schematic graph showing an example spectrum of a reference signal and an example spectrum of a Doppler-shifted return signal according to an embodiment;

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

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

[0014] IE is a graph using a symmetrical LO signal, according to an embodiment, and shows the return signal in this frequency-time graph as a dashed line when there is no Doppler shift;

[0015] Figure 1F is a graph similar to FIG. 1E using a symmetrical LO signal and showing the return signal in this frequency-time graph as a dashed line when there is a non-zero Doppler shift, according to an embodiment;

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

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

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

[0019] Figure 2D It is shown that according to the embodiment Figure 2A A block diagram of example components of a scanning optical component of a system;

[0020] Figure 2E 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 is a block diagram showing an example of a conventional assembly including a polygonal reflector rotated by a motor to reflect an incident light beam over a field of view;

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

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

[0024] Figure 5B It is shown that according to the embodiment Figure 5A A schematic diagram of an example of a cross-sectional top view of a polygonal deflector;

[0025] Figure 5C It is shown that according to the embodiment Figure 5A A schematic diagram of an example of a side view of a planar optical fiber array of an assembly;

[0026] Figure 5D It is shown that according to the embodiment Figure 5A A schematic diagram of an example of a side view of a lens assembly of an assembly;

[0027] Figure 5E is a diagram showing the embodiment in two rotational positions Figure 5B A schematic diagram of an example of a polygonal deflector;

[0028] Fig. 5F It is shown that according to the embodiment Figure 5A A schematic diagram of an example of a partial cross-sectional side view of a polygonal deflector;

[0029] Figure 5G It is shown that according to the embodiment Figure 5A A schematic diagram of an example of a cutaway cross-sectional view of a toric lens used in an assembly of;

[0030] Figure 6 is a flow chart 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 is a schematic diagram showing an example of a LIDAR system including two polygon scanners according to an embodiment;

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

[0033] Fig. 9 is a schematic diagram showing a cross-sectional view of an example of two polygon scanners according to an embodiment;

[0034] Fig.10 is a graph showing an example of elevation and azimuth angles sampled using a LIDAR system according to an embodiment;

[0035] Fig.11is a flow chart illustrating an example of a method of operating a LIDAR system according to an embodiment;

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

[0037] Fig.13 A chip set according to an embodiment is shown. DETAILED DESCRIPTION

[0038] A method and apparatus for scanning of a LIDAR system and a system and computer readable medium are described. Some embodiments are described below in the context of a high-resolution LIDAR system. An embodiment is described in the context of optimizing the scanning of a beam by a unidirectional scanning element of a LIDAR system (including Doppler and non-Doppler LIDAR systems). An embodiment is described in the context of optimizing the scanning of a beam by a polygonal deflector, such as a polygonal deflector configured to deflect or refract a beam incident on a face of the polygonal deflector from the interior of the polygonal deflector. The polygonal deflector can be a polygonal shaped element with many faces based on a polygonal structure. Each face is configured to deflect over a field of view (e.g., reflect an incident beam onto a face, or refract an incident beam from the interior of the polygonal shaped element) as the polygonal deflector rotates about an axis. The polygonal deflector repeatedly scans the beam over the field of view as the beam transitions over a facet interruption between adjacent faces during rotation of the polygonal deflector. Some embodiments are described in the context of a single front-mounted high-resolution Doppler LIDAR system on a personal vehicle; however, various embodiments are not limited to this context. Some embodiments may be used in the context of laser etching, surface processing, bar code scanning, and refraction scanning of light beams.

[0039] Some scanning systems utilize polygonal reflectors, which are regularly shaped reflective objects that rotate relative to a static incident beam. The reflective surface causes repeated reflections of light in directions across the field of view. Such polygonal reflectors may have several disadvantages. For example, an incident beam on a reflective surface inherently limits the field of view because the field of view cannot include angles that include the incident beam coplanar with the reflective surface. If the field of view is extended to include an angle that includes the incident beam and thus the field of view is inherently limited by the incident beam, useful return beam data cannot be obtained. This may 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 the present disclosure may use a refractive beam-steering assembly and method utilizing a polygonal deflector that deflects (e.g., refracts) an incident beam across the field of view rather than reflecting the incident beam across the field of view. A polygonal deflector can enhance both the field of view and the duty cycle because the incident beam is directed from the inside of the deflector and thus 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, the polygonal deflector including a plurality of faces; and a motor, the motor being rotatably coupled to the polygonal deflector and configured to rotate the polygonal deflector around a first axis orthogonal to the first plane. The device also includes an optical component positioned inside the polygonal deflector to collimate the light beam incident on the face from the inside of the polygonal deflector. Each face is configured to refract the light beam in the first plane between the first angle and the second angle as the polygonal deflector rotates around the first axis. Systems and methods for implementing the LIDAR device can be provided.

[0041] 1. Phase Encoding Detection Overview

[0042] To measure distance using an optical phase coded signal, the transmitted signal is in phase with the carrier (phase = 0) for part of the transmitted signal, and then changes over short time intervals by one or more phase changes represented by the symbol Δφ (so phase = Δφ), repeatedly switching between two or more phase values ​​on the transmitted signal. The shortest interval of constant phase is called the pulse duration The encoding parameter of , and is usually the duration of a few time segments of the lowest frequency in the band. Reciprocal, 1 / , is the baud rate, where each baud indicates one symbol. The number of such constant phase pulses N during the time of the transmitted signal is the number of symbols N and represents the length of the code. In binary coding, there are two phase values, the phase with the shortest interval can be regarded as one value of 0 and the other value of 1, so the symbol is 1 bit, and the baud rate is also called the bit rate. In polyphase coding, there are multiple phase values. For example, 4 phase values, such as Δφ {0, 1, 2 and 3}, for Δφ = / 2 (90 degrees), respectively equal to {0, / 2, and 3 / 2}; and thus, the 4 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) refers to a digital modulation scheme that transmits data by changing (modulating) the phase of a reference signal (carrier). Changing the sine and cosine inputs at precise times profoundly affects the modulation. At radio frequency (RF), PSK is widely used for wireless local area networks (LANs), RF identification (RFID), and Bluetooth communications. Alternatively, instead of operating on a constant reference wave, the transmission can operate on itself. The phase changes of a single transmitted waveform can be regarded as symbols. In this system, the demodulator determines the phase of the received signal rather than the change in the phase (relative to the reference wave) itself. Since this scheme depends on the difference between consecutive phases, it is called differential phase shift keying (DPSK). DPSK can be significantly simpler to implement in communication applications than ordinary PSK because the demodulator does not need to have a copy of the reference signal to determine the exact phase of the received signal (thus being a non-coherent scheme).

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

[0045] To achieve acceptable range accuracy and detection sensitivity, a direct long-range LIDAR system might use short-pulse lasers with low pulse repetition rates and very high pulse peak powers. High pulse powers can result in rapid degradation of optical components. Chirped and phase-coded LIDAR systems can use long optical pulses with relatively low peak optical powers. In this configuration, range accuracy can increase with the chirp bandwidth or length and the bandwidth of the phase code rather than with pulse duration, so excellent range accuracy can still be achieved.

[0046] Useful optical bandwidths have been achieved using broadband radio frequency (RF) electrical signals to modulate an optical carrier. With regard to LIDAR, using the same modulated optical carrier as a reference signal (which is combined with the return signal at the optical detector) can produce in the resulting electrical signal a relatively low beat frequency in the RF band that is proportional to the frequency or phase difference between the reference signal and the return optical signal. This beat frequency detection of the frequency difference at the detector is known as heterodyne detection. Heterodyne detection has several advantages known in the art, such as the advantage of using readily available and inexpensive availability of RF components.

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

[0048] In some instances, these improvements provide distance, with or without target velocity, in a thin pen laser beam of appropriate frequency or phase content. When such a beam is swept across a scene, information about the position and velocity of surrounding objects can be obtained. This information can be used in control systems for autonomous vehicles, such as self-driving or driver-assisted cars.

[0049] For optical ranging applications, coherent PSK can be used since the transmitter and receiver are in the same device. The carrier frequency is the optical frequency fc and the RF f0 is modulated onto the optical carrier. The number of symbols N and the duration are chosen The length of the transmitted signal is selected to achieve the desired range accuracy and resolution. The pattern of symbols is selected so as to be distinguishable from the coded signal and other sources of noise. Thus, 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 blocks of symbols, where each block is long enough to provide a strong correlation with the reflected or backscattered return even in the presence of noise. The transmitted signal may consist of M blocks of N symbols per block, where M and N are non-negative integers.

[0050] Figure 1A 1 is a schematic graph 120 showing an example transmit signal as a series of binary digits and a return optical signal for measuring distance according to an embodiment. The horizontal axis 122 indicates time in arbitrary units after a start time at zero. The vertical axis 124a indicates the amplitude of the optical transmit signal at a frequency fc+f0 in arbitrary units relative to zero. The vertical axis 124b indicates the amplitude of the optical return signal at a frequency fc+f0 in arbitrary units relative to zero and is offset from axis 124a to separate the traces. Trace 125 represents M The transmitted signal of N binary symbols has a phase change such as Figure 1A , resulting in codes starting with 00011010 and continuing as indicated by the ellipsis. Trace 126 represents an idealized (noise-free) return signal that is scattered from an object that is not moving (thus the return is not Doppler shifted). The amplitude is reduced, but the code 00011010 is recognizable. Trace 127 represents an idealized (noise-free) return signal that is scattered from an object that is moving and is therefore Doppler shifted. The return is not at the proper optical frequency fc+f0 and is not well detected in the expected frequency band, so the amplitude is reduced.

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

[0052] (1)

[0053] Where c is the speed of light in the medium, vo is the observer's velocity, v s is the velocity of the source along the vector connecting the source to the receiver. Note that if the observer and source move in the same direction with the same velocity on the vector between them, then the two frequencies are the same. The difference between the two frequencies Δf = f'-f is the Doppler shift Δf D , causing the problem of distance measurement, given by Equation 2.

[0054] (2)

[0055] It should be noted that the magnitude of the error increases with the frequency f of the signal. It should also be noted that for a stationary LIDAR system (v o = 0), for a velocity of 10 meters per second (v s = 10) moving objects, and visible light with a frequency of about 500 THz, the error is about 16 megahertz (MHz, 1MHz=10 6 Hertz, Hz, 1 Hz = 1 cycle per second). In various embodiments described below, Doppler shift errors are detected and used to process data for calculating distance.

[0056] In phase coded ranging, the arrival of a phase coded reflection can be detected in the return by cross-correlating the transmitted signal or other reference signal with the return signal. The cross-correlation can be implemented by cross-correlating the code for the RF signal with the electrical signal from the optical detector using heterodyne detection and then mixing down back to the RF band. The cross-correlation for any one lag can be calculated by convolving the two traces, for example, multiplying the corresponding values ​​in the two traces and summing all the points in the traces, then repeating for each lag. The cross-correlation can be implemented by multiplying the Fourier transform of each of the two traces and then performing an inverse Fourier transform. Forward and inverse fast Fourier transforms can be efficiently implemented in hardware and software.

[0057] It should be noted that after the amplitude and phase of the return are detected at the optical detector, a cross-correlation calculation can be performed with the analog or digital electrical signal. In order to move the signal at the optical detector to the RF frequency range where it can be easily digitized, the optical return signal is optically mixed with a reference signal before hitting the detector. A phase-encoded copy of the transmitted optical signal can be used as a reference signal, but it is also possible and usually preferred to use a continuous wave carrier frequency optical signal output by the laser as a reference signal and capture both the amplitude and phase of the electrical signal output by the detector.

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

[0059] (3)

[0060] For an idealized (noise-free) return signal scattered from a moving object (thus, the return is Doppler shifted), the return signal does not include phase encoding in the appropriate frequency bin, the correlation remains low at all time lags, and the peak is not easily detected, and is usually undetectable in the presence of noise. Thus, Δt is not easily determined, nor is the range R easily generated.

[0061] The Doppler shift can be determined in the electrical processing of the return signal and can be used to correct the cross-correlation calculations. Thus, peaks can be found more easily and distances can be determined more easily. Figure 1B 1 is a schematic graph 140 showing an example spectrum of a transmitted signal and an example spectrum of a Doppler shifted complex return signal according to an implementation. The horizontal axis 142 indicates the RF frequency offset from the optical carrier fc in arbitrary units. The vertical axis 144a indicates the amplitude of a particular narrow frequency window in arbitrary units relative to zero, also known as the spectral density. The vertical axis 144b indicates the spectral density in arbitrary units relative to zero and is offset from axis 144a to separate the traces. Trace 145 represents the transmitted signal; and, a peak occurs at the appropriate RF f0. Trace 146 represents an idealized (noise-free) complex return signal, which is backscattered from an object moving toward the LIDAR system and is therefore Doppler shifted to a higher frequency (called a blue shift). The return does not have a peak at the appropriate RF f0; instead, the blue shift Δf D to the frequency shifted frequency f S In practice, +Δf is determined using a complex return representing the in-phase and quadrature (I / Q) components of the return. D The peak at , thus, the direction of the Doppler shift, and thus the direction of motion of the target in the vector between the sensor and the object, can be detected from a single return.

[0062] In some Doppler compensation implementations, rather than finding Δf 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 , instead, the cross-spectrum of the in-phase and quadrature components of the down-mixed return signal in the RF band can be acquired more efficiently. Figure 1C 1 is a schematic graph 150 showing an example cross-spectrum according to an embodiment. The horizontal axis 152 indicates the frequency shift in arbitrary units relative to a reference spectrum; and the vertical axis 154 indicates the magnitude of the cross-spectrum in arbitrary units relative to zero. Trace 155 represents the cross-spectrum with an idealized (noise-free) return signal generated by a moving object toward the LIDAR system ( Figure 1B The blue shift Δf D1 = Δf D ) and an object moving away from the LIDAR system (redshift Δf D2 ) is produced. When one of the components is blue-shifted by Δf D1 The peak value 156a appears when one component is redshifted by Δf D2 Another peak 156b appears when Δf is equal to Δf. Thus, the Doppler shift is determined. These shifts can be used to determine the signed velocity of objects approaching near the LIDAR, such as for collision avoidance applications. However, without I / Q processing, peaks may appear at + / - Δf D1 Both and + / - Δf D2 At both, 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 so that the peak 135 is evident in the Doppler compensated Doppler shift return at the lag Δt, and the range R can be determined. In some embodiments, simultaneous I / O processing can be performed. In some embodiments, serial I / Q processing can be used to determine the sign of the Doppler return. In some embodiments, errors caused by Doppler shift can be tolerated or ignored; and no Doppler correction is applied to the range measurement.

[0064] 2. Chirp Detection Overview

[0065] Figure 1D 1 is a set of graphs showing 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 of milliseconds (ms, 1 ms = 10 -3 100 indicates the power of the light beam used as the transmitted optical signal. The vertical axis 104 in the graph 100 indicates the power of the transmitted signal in arbitrary units. The trace 106 indicates the power of the transmitted signal in a finite pulse duration. Turn on the power inside, Starting at time 0. Graph 110 indicates the frequency of the transmitted signal. Vertical axis 114 indicates the frequency of the transmission in arbitrary units. Trace 116 indicates the frequency of the pulse over the duration of the pulse. The frequency increases from f1 to f2, so it has a bandwidth of B = f2 - f1. The rate of change of frequency 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, which is the same as graph 110. The chirp (e.g., frequency envelope 116) of graph 110 is also plotted as a dashed line on graph 160. The first return signal is given by frequency envelope 166a, which may represent the transmitted reference signal weakened in intensity (not shown) and delayed by Δt. When the return signal is received from the external object after covering a spacing of 2R, where R is the distance to the target, the return signal starting at the delay time Δt may be given by 2r / c, where c is the speed of light in the medium (approximately 3x10 8 meters per second, m / s), and is related according to equation 3 above. During this time, the frequency has changed by an amount that depends on the distance, called f R , and is given by the rate of change of frequency multiplied 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. Thus, the range R is given by Equation 4b.

[0069] (4b)

[0070] If the return signal arrives after the pulse is fully transmitted, that is, if 2R / c is greater than , 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 return signal overlaps 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 there may be deviations from the absolute distance due to uncertainty in the speed of light in the medium, this is a nearly constant error and the relative distance based on the frequency difference is still very accurate.

[0071] In some cases, the spot illuminated by the transmitted beam (pencil beam cross section) encounters two or more different scatterers at different distances, such as the front and back sides of a semi-transparent object, or closer and farther parts of an object at varying spacings from the LIDAR, or two separate objects within the illuminated spot. In such a case, a second signal of reduced intensity and different delay will also be received, indicated by trace 166b on graph 160. This will have f given at different distances using equation 4b R In some cases, multiple additional return signals are received.

[0072] The graph 170 depicts the difference frequency f between the first return signal 166a and the reference chirp 116. R The horizontal axis 102 indicates time, and Figure 1D As in all other aligned graphs in FIG. 1 , vertical axis 164 indicates frequency difference on a much larger scale. Trace 176 depicts the constant frequency f measured in response to the transmitted chirp. R , indicating a specific distance as given by Equation 4b. If present, the second return signal 166b will produce a different, larger f in the de-chirping process. R values ​​(not shown); therefore, using Equation 4b produces a larger distance.

[0073] Dechirping can be performed by directing both the reference optical signal and the return optical signal to the same optical detector. The electrical output of the detector can be dominated by a beat frequency that is equal to or otherwise dependent on the frequency difference of the two signals focused on the detector. The Fourier transform of the electrical output signal will produce a peak at the beat frequency. The beat frequency is in megahertz (MHz, 1 megahertz = 10 6 Hertz = 10 per second 6 cycles) in the radio frequency (RF) range rather than in the terahertz (THz, 1THz=10 12 The return signal can be mixed with a continuous wave (CW) as a local oscillator (rather than a chirp as a local oscillator). This causes the detected signal to be the chirp itself (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 generally higher. The positive aspects of coherent detection are otherwise preserved.

[0074] In some embodiments, the LIDAR system is modified to produce simultaneous up and down chirps. This approach can eliminate variability resulting from differences in object velocity, or changes in the position of the LIDAR relative to the object that actually changes distance, or transient scatterers in the beam, etc., or some combination. The approach can ensure that the Doppler shift and distance measured on the up and down chirps are indeed the same, and can be most usefully combined. The Doppler scheme can ensure parallel capture of pairs of returns that are asymmetrically shifted in frequency space for high probability of correct compensation.

[0075] FIG. 1E is a graph using a symmetrical LO signal according to an embodiment and shows the return signal in this frequency time graph as a dashed line when there is no Doppler shift. -5 The vertical axis indicates the optical transmission signal relative to the carrier frequency f c or the reference signal frequency, in GHz (10 9 Hertz is an example unit. During one pulse duration, a beam is generated that includes two optical frequencies at any time. 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, so that both the transmitted and returned signals can be optically separated by high-pass or low-pass filters or some combination thereof, with the passbands being from the passband f1 to the passband f2. p For example, f1 < f2 < f p < f3 < f4. As shown, a higher frequency can provide an up-chirp and a lower frequency can provide a down-chirp. In some embodiments, a higher frequency produces a down-chirp and a lower frequency produces an up-chirp.

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

[0077] Due to the sideband symmetry, the bandwidth of the two optical chirps can be the same if the same order sidebands are used. In some embodiments, other sidebands are used, for example, two second order sidebands are used, or one first order sideband and one non-overlapping second sideband are used, or some other combination.

[0078] When selecting the transmit (TX) and local oscillator (LO) chirp waveforms, it is advantageous to ensure that the system's frequency shift band maximizes the use of the available digitizer bandwidth. Typically, this is accomplished by shifting the up-chirp or down-chirp frequency so that the range frequency beat is close to zero.

[0079] Figure 1F is a graph similar to FIG. 1E using a symmetrical LO signal and showing the return signal in this frequency time graph as a dashed line when there is a non-zero Doppler shift. In the case of a chirped waveform, time-separated I / Q processing (aka time domain multiplexing) can be used to overcome the hardware requirements of other methods. In this case, an AOM can be used to break the range-Doppler ambiguity of the real-valued signal. In some embodiments, a scoring system can be used to pair up and down chirp returns. In some embodiments, I / Q processing can be used to determine the sign of the Doppler chirp.

[0080] 3. Overview of Optical Inspection Hardware

[0081] Figure 2A 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 light beam (e.g., a carrier wave 201) that is phase or frequency modulated in a modulator 282a, either before or after a beam splitter 216, to produce a phase coded or chirped optical signal 203 having a duration D. The beam splitter 216 splits the modulated (or, as shown, unmodulated) optical signal for use in a reference path 220. A target beam 205, also referred to herein as a transmitted signal, may produce most of the energy of the beam 201. A modulated or unmodulated reference beam 207a may also be produced that may have a much smaller amount of energy that is still sufficient to produce good mixing with the return light 291 scattered from an object (not shown). As shown in FIG. Figure 2AAs shown in , the reference beam 207a is separately modulated in the modulator 282b. The reference beam 207a passes through the reference path 220 and is directed to one or more detectors as the reference beam 207b. In some embodiments, the reference path 220 introduces a known delay that is sufficient to cause the reference beam 207b to reach the detector array 230 within the distance range of interest along with scattered light from objects external to the LIDAR. In some embodiments, the reference beam 207b is referred to as a local oscillator (LO) signal, such as if the reference beam 207b is generated locally from a separate oscillator. In various embodiments, from less to more flexible methods, the reference beam 207b can be caused to reach the scattered or reflected field by: 1) placing a mirror in the scene to reflect a portion of the transmitted beam back to the detector array so that the path length is well matched; 2) using fiber optic delays to closely match the path length and broadcasting the reference beam with optical components near the detector array, such as Figure 2A , with or without path length adjustment to compensate for phase or frequency differences observed or expected at a particular distance; or 3) using a frequency shifting device (acoustic-optic modulator) or a time delay of a local oscillator waveform modulation (e.g., in modulator 282b) to produce a separate modulation to compensate for path length mismatch; or some combination. In some embodiments, the object is close enough and the duration of the transmission is long enough that the return signal sufficiently overlaps the reference signal without delay.

[0082] The transmit signal is then transmitted to illuminate the area of ​​interest, such as through one or more scanning optical components 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 approximately 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 produce an optical signal of the characteristic to be appropriately detected. The frequency, phase or amplitude of the interference pattern, or some combination, 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 distance 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 selection. The frame rate is the sampling bandwidth, often referred to as the "digitizer frequency". The only fundamental limit to the distance range is the coherence length of the laser and the length of the chirp or unique phase code before it repeats (for unambiguous ranging). This is enabled because any digital record of the returned heterodyne signal or bits can be compared or cross-correlated with any portion of the transmitted bits from the previous transmission history.

[0083] The collected data is made available to a processing system 250, such as the following reference Figure 7 The computer system described, or referenced below Figure 7 The scanner control module 270 provides scanning signals to drive the scanning optical component 218. The scanner control module 270 may include instructions to perform the same Figure 6 One or more steps of the method 600 are associated with the flowchart of the processing system 250. A signed Doppler compensation module (not shown) in the processing system 250 can determine the sign and magnitude of the Doppler shift, as well as the correction range and any other corrections based thereon. The processing system 250 may include a modulation signal module (not shown) to send one or more electrical signals that drive the modulators 282a, 282b. In some embodiments, the processing system also includes a vehicle control module 272 to control a vehicle on which the system 200 is installed.

[0084] Optical coupling for diffusing or focusing on a target or for focusing beyond the pupil plane is not depicted. As used herein, an optical coupler is any component that affects the propagation of light within a spatial coordinate to direct 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 alone or in some combination.

[0085] Figure 2A Also shown are example components for a simultaneous up- and down-chirp LIDAR system according to an embodiment. Figure 2A As depicted in , modulator 282a can be a frequency shifter added to the optical path of the transmit beam 205. In some embodiments, the frequency shifter is added to the optical path of the return beam 291 or to the reference path 220. The frequency shifter can be added as modulator 282b on the local oscillator (LO, also called the reference path) side or the transmit side (before the optical amplifier) ​​because devices used as modulators (e.g., acousto-optic modulators, AOMs) have some associated losses, so it may be disadvantageous to place lossy components on the receive side or after the optical amplifier. The optical frequency shifter can shift the frequency of the transmit signal (or return signal) by a known amount Δfs relative to the frequency of the reference signal so that the beat frequencies of the up-chirp and down-chirp occur in different frequency bands - when analyzing the electrical signal output by the optical detector 230, the beat frequencies can be picked up by, for example, an FFT component in the processing system 250. For example, if the blue shift that causes the distance effect is f B , then the beat frequency of the up-chirp will be shifted and increased at f B + Δfs, and the beat frequency of the down-chirp will be shifted down to f B– Δfs. Thus, the up-chirp will be in a higher frequency band than the down-chirp, thereby separating them. If Δfs is greater than any expected Doppler effect, there will be no ambiguity in the distances associated with the up-chirp and down-chirp. The measured beats can then be corrected with the correct sign value of the known Δfs to obtain the appropriate up-chirp and down-chirp distances. In some embodiments, the RF signal coming out of the balanced detector is directly digitized and the frequency bands are separated via FFT. In some embodiments, the RF signal coming out of the balanced detector is pre-processed with analog RF electronics to separate a low frequency band (corresponding to one of the up-chirp and down-chirp) that can be directly digitized, and a high frequency band (corresponding to the opposite chirp) that is electronically mixed down to baseband and then digitized. Various such embodiments provide a path to match the frequency band of the detected signal to the available digitizer resources. In some embodiments, the modulator 282a is excluded (e.g., direct ranging).

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

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

[0088] In some embodiments, the scanner control module 270 provides a signal 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, wherein one motor is mechanically coupled to the oscillating scanning element 226 and the other motor is mechanically coupled to the unidirectional scanning element 228. In one embodiment, based on the signal 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 value of a parameter (e.g., angular velocity, etc.) in the signal. The scanner control module 270 can determine the value of the parameter in the signal so that the light beam 205 is scanned by the oscillating scanning element 226 in a desired scanning pattern (e.g., between angles -A and +A along the axis 222) and / or by the unidirectional constant speed scanning element 228 in a desired scanning pattern (e.g., between angles =D and +D along the axis 224).

[0089] 4. Coherent LIDAR system for refracted beam steering

[0090] Figure 3 The diagram includes a motor (not shown) that is rotated to move the image in the field of view 310 (e.g., Figure 3300 is a block diagram of an example of an assembly 300 of a polygonal reflector 304 that reflects an incident light beam 311 within a plane of the hexagonal reflector (between a first angle and a second angle). The polygonal reflector 304 includes a plurality of reflective surfaces 306 (e.g., six in a hexagonal reflector). Each surface 306 reflects an incident light beam 311 into a reflected light 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 light beam 311 encounters a first and second interruption in the surface 306. The field of view 310 can be limited by the position of the incident light beam 311 that is coplanar with the surface 306, because the field of view 310 cannot include angles that coincide with the incident light beam 311. The field of view 310 cannot include the incident light beam 311 because useful return beam data cannot be collected for those scan angles. Thus, the polygonal reflector 304 has a limited field of view 310 due to the nature of the incident light beam 311 being coplanar and incident on the outer surface of the surface 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 that the face 306 reflects the light beam 312 over the field of view 310 to the total time that the assembly 300 operates. The duty cycle can be about 50% of that of a conventional polygonal reflector 304.

[0091] Figure 4 4 is a block diagram showing an example of an assembly 400 including a polygonal deflector 404 that is rotated by a motor 232 to deflect an incident light beam 411 from an interior 432 of the deflector 404. The polygonal deflector 404 may include a unidirectional constant speed scanning element 228 that may be Figure 2AThe unidirectional constant velocity scanning element 228 may or may not be used in the system 200. The incident light beam 411 may 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 light beam 411 may be directed from the outside of 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 light beams 411 are provided and shaped by the optical component 405 before being directed to the face 406. The face 406 may refract the incident light beam 411 into a refracted light beam 412 based on Snell's law according to the refractive index of the face 406 and the incident angle of the light beam 411 on the face 406. In one embodiment, the field of view 410 is defined by the refracted light beam 412 between the face interruptions of the incident light beam 411 on the first face 406. In one embodiment, the field of view 410 is greater than the field of view 310 in the polygonal reflector 304. In one embodiment, the field of view 410 is about 90 degrees (e.g., a polygonal deflector 404 made of a high index material such as silicon) or about 50 degrees (e.g., a polygonal deflector 404 made of a non-exotic material), compared to a field of view 310 that is less than or about 90 degrees. In one embodiment, the width of the polygonal deflector 404 (e.g., defined as the distance between opposing faces 406) is about 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 about the same as the width of each face 306. Thus, the space savings 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., a collimator to direct the incident light beam 311). In one embodiment, the polygonal deflector 404 has a width of about 70 mm (e.g., measured between the faces 406 on opposite sides of the deflector 404) and a length of about 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 direct the incident light beam 311) measured about 50 mm from the polygonal reflector 304 and spaced about 25 mm therefrom. Thus, the front region length of the polygonal deflector 404 is about 70 mm compared to about 140 mm for the polygonal reflector 304. In one embodiment, the incident light beam 411 is continuously refracted by each face 406 across the field of view 410 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 about 70% and / or about 80%. The duty cycle may be based on a ratio of a first time based on refraction of the incident light beam 411 and a second time based on rotation of the polygonal deflector 404 and shaping of the incident light beam 411 .

[0092] Figure 5A 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 an interior 532 of the deflector 501 . Figure 5B It is shown Figure 5A 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 or has a high transmissive property (e.g., greater than 90%) at the wavelength of the light beam 580. FIG. 5A to FIG. 5B A hexagonal deflector is depicted (e.g., six sides), but various embodiments are not limited to hexagonal deflectors and may include any polygonal deflector having any number of faces, and, for example, need not be a regular polygon having faces 506 of equal angles and equal widths, but may be an irregular polygon having faces 506 of unequal angles or unequal widths.

[0093] The polygonal deflector 501 may be rotatably coupled to a 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 the first plane 541 ( Figure 5B plane), wherein the polygonal deflector 501 rotates at a rotational speed 502. FIG. 5A to FIG. 5B The rotation speed 502 is depicted as being clockwise, but the rotation speed 502 may be counterclockwise. In one embodiment, the magnitude of the rotation speed is about 100 revolutions per minute (rpm) to about 1000 rpm and / or about 10 rpm to about 10,000 rpm. In some embodiments, the magnitude of the rotation speed may be one order of magnitude greater than the numerical 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 an inner surface 536 of the polygonal deflector 501 defining an interior 532. The motor 534 may include a rotor 522 actuated by a coil 524 to rotate the polygonal deflector 501 around a rotation axis 540. The motor 534 may include a stator 526 partially positioned in the interior 532 of the polygonal deflector 501 and defining a cavity 530, in which an optical component is positioned to turn an incident light beam 580 on the face 506. The stator can output an electromagnetic field to drive the coil 524 to actuate the rotor 522. In one embodiment, the motor 534 is manufactured by Nidec BLDC motors manufactured by Corporation, Braintree MA.

[0094] In one embodiment, one or more optical components are positioned in the interior 532 of the polygonal deflector 501 to steer an incident light beam 580 on the face 506. In one embodiment, the optical components include a lens assembly 505 including one or more lenses and / or a pair of mirrors 528a, 528b. In one embodiment, the lens assembly 505 is a free-form toric single lens.

[0095] Figure 5G It is shown Figure 5A Schematic diagram of an example of a cut-away cross-sectional view of a single toric lens 505' used in assembly 500 of . In one embodiment, toric lens 505' is used in place of lens assembly 505. In one embodiment, toric lens 505' is selected because it is characterized by some properties of a cylindrical lens and other properties of a spherical lens, and / or is a hybrid lens in the shape of an annulus, which is an optical combination of a first lens and a second lens of lens assembly 505. In one embodiment, the software instructions of module 270 may include one or more instructions to determine one or more parameter values ​​of toric lens 505' that are equal to lens assembly 505. In one embodiment, light beam 580 is emitted with light emitted by a lens assembly 505 mounted at a focal plane (e.g., Figure 5A The planar optical fiber array 529 in the plane 543) is emitted to the interior 532.

[0096] Figure 5C It is shown that according to the embodiment Figure 5A Schematic diagram of an example of a side view of a planar optical fiber array 529 of an assembly 500. In one embodiment, Figure 5C Along with Figure 5A The planar optical fiber array 529 includes a plurality of optical fibers 582a, 582b, 582c spaced apart by corresponding transverse spacings 584a, 584b. Figure 5CThree optical fibers 582 are depicted in the planar optical fiber array 529, but this is only an example, and more or less than three optical fibers 582 may be provided in the planar optical fiber array 529. In some embodiments, the lateral spacing 584a, 584b is the same between adjacent pairs of optical fibers. In some embodiments, the lateral spacing 584a, 584b is different between adjacent pairs of optical fibers (e.g., the spacing 584a between optical fibers 582a, 582b is different from the spacing 584b between optical fibers 582b, 582c). In one embodiment, a corresponding light beam 580 is emitted from the tip of each optical fiber 582, and thus, multiple light beams 580 are emitted from the tip of the optical fiber 582 within the interior 532 (e.g., the cavity 530 of the stator 526). In an example embodiment, the planar optical fiber array 529 is a fixed pitch optical fiber array and planar lightwave circuit (PLC) connection, manufactured by Zhongshan Meisu Technology Co., Ltd. in Zhongshan City, Guangdong Province, China.

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

[0098] Figure 5D It is shown that according to the embodiment Figure 5A Schematic diagram of an example of a side view of a lens assembly 505 of an assembly 500. In one embodiment, Figure 5D along Figure 5B The plane 541 is intercepted (for example, perpendicular to Figure 5A In one embodiment, the lens assembly 505 includes a first lens 582 that collimates a divergent light beam 580 reflected from the second reflector 528b to the first lens 582. In one embodiment, the first lens 582 is an aspheric lens whose focal length is selected so that the divergent light beam 580 from the second reflector 528b is collimated by the aspheric lens. In one embodiment, the focal length of the aspheric lens extends beyond the second reflector 528b.

[0099] like Figure 5D , a collimated light beam 580' from a first lens 582 may be steered by a second lens 584. In one embodiment, the second lens 584 is a positive cylindrical lens that converges the light beam based on the focal length of the positive cylindrical lens. In one embodiment, the converging light beam 580'' from the second lens 584 is refracted by an inner surface 536 of the polygonal deflector 501 defining the interior 532, such that the light beam 580''' is collimated within the polygonal deflector 501 and incident on the face 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 standard optical fiber with a mode field diameter (MFD) of about 10 μm and / or about 6-14 μm MFD is used to produce a light beam 580' having a diameter of about 8-10 mm and / or about 6-12 mm. In one embodiment, the spacing 584a, 584b of the beams in the fiber array 529 will be increments or multiples of about 127 μm, resulting in a total angular spread 560 of about 1-4 degrees. In one embodiment, the curvature of the positive cylindrical lens is the same as the curvature of the inner surface 536 and / or the transition of refractive index from the positive cylindrical lens to air is opposite to the transition of 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 about 1.7 or in the range from about 1.3 to about 1.8, and the refractive index of the polygonal deflector 501 is about 1.7 in the range from about 1.3 to about 1.8, and the curvature of the positive cylindrical lens and the inner surface 536 is about 25.4 mm radius and / or in the range from about 20 mm to about 30 mm and / or in the range from about 15 mm to about 40 mm. The beam 580''' incident on the surface 506a is about 25.4 mm radius and / or in the range from about 20 mm to about 30 mm and / or in the range from about 15 mm to about 40 mm. Figure 5B Depicted in Figure 5B shows a plane 541 or Figure 5D Light beam 580''' in the plane.

[0100] Figure 5E is shown in two rotational positions 550a, 550b Figure 5B Schematic diagram of an example of a polygonal deflector 501. In one embodiment, a collimated light beam 580''' incident on the face 506a from the interior 532 is refracted by the face 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 light beam 580''' on the face 506a relative to the normal to the face 506a (inside), n2 is the refractive index of the medium surrounding the polygonal deflector 501 where the light beam 512 is refracted (e.g., air = 1), and θ2 is the angle of refraction of the light beam 512a relative to the normal to the face 506a (outside). The angle of refraction can be measured as an angle 552a relative to an axis 544 orthogonal to the axis of rotation 542. As Figure 5E , a plurality of light beams 512a are refracted at angles 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, an incident light beam 580''' may be refracted by one side of face 506a (e.g., refracted light beam 512a at angle 552a) to an opposite side of face 506a relative to axis 544 (e.g., refracted light beam 512b at angle 552b), thereby defining a field of view of the refracted light beams 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 a high refractive index material, such as silicon).

[0103] Fig. 5F It is shown Figure 5A Schematic diagram of an example of a partial cross-sectional side view of a polygonal deflector 501. In one embodiment, Fig. 5F exist Figure 5A In one embodiment, an incident light beam 580''' is depicted in plane 543, showing an angular spread 560 of the incident light beam 580'''. In one embodiment, the angular spread 560 is related to the lateral spacing 584 of the optical fibers 582 of the planar optical 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 face 506 forms a non-orthogonal angle 574 with the top or bottom of the polygonal deflector 501. In one embodiment, the non-orthogonal angle 574 is any angle other than 90 degrees, and / or an angle within a range from about 75 degrees to about 105 degrees, and / or an angle within a range from about 60 degrees to about 120 degrees. In addition, although Fig. 5F The non-orthogonal angle 574 in is less than 90 degrees, but the non-orthogonal angle 574 can be greater than 90 degrees, for example, Figure 5AThe non-orthogonal angle 574 of the middle face 506b. Angle 574 can be orthogonal and / or about 90 degrees for some or all of the faces 506. Angle 574 can be non-orthogonal for each face 506, but vary for one or more faces, for example, less than about 90 degrees for one or more faces 506, but greater than about 90 degrees for one or more faces 506. An advantage of the arrangement of one or more faces 506 having an angle 574 less than 90 degrees and one or more faces 506 having an angle 574 greater than 90 degrees is that the plane 543 ( Fig. 5F ) can alternate between being above the transverse axis 544 (for face 506 having angle 574 less than 90 degrees) to being below the transverse axis 544 (for face 506 having angle 574 greater than 90 degrees). This can allow beam 512 to be scanned over multiple distances within plane 543, for example, to capture return beam data from objects within these multiple distances.

[0106] In one embodiment, incident light beams 580'"' on facet 506 have an angular spread 560 that widens to a larger angular spread 562 after being refracted by facet 506. In one embodiment, the angular spread 562 widens based on a ratio of the refractive index of the polygonal deflector 501 (e.g., n=1.5) to the refractive index of the medium surrounding the polygonal deflector 501 (e.g., air=1). In an example embodiment, if each light beam 580'"' has an angular spacing of approximately 1 degree incident on facet 506, each refracted light beam 512 has an angular spacing of approximately 1.5 degrees, e.g., the product of the angular spacing of the light 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 the plane 543 is changed by refraction at the facet 506. In one embodiment, the centerline 570 of the incident beam 580''' on the facet 506 is refracted by the facet 506 into the centerline 572 of the refracted beam 512 in the plane 543 based on Snell's law in Equation 5. Thus, in addition to the increased angular spread 562 of the refracted beam 512, the facet 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 the angular spread 560 is about 50%, for example, from about 1 degree of angular spread 560 between the beams 580 to about 1.5 degrees of angular spread 562 between the beams 580. In one embodiment, the change in the centerline 572 relative to the centerline 570 is about +5, +10, -5, -10 degrees.

[0108] 5. Vehicle Control Overview

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

[0110] Figure 2E 2 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 a 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 the processing system 250. In some embodiments, the vehicle has an onboard processor 246, such as Figure 8 In some embodiments, the onboard processor 246 communicates with the remote processor by wire or wirelessly, such as Figure 7 246, or uses the processing system 250 of the LIDAR system 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 steering or braking system of the vehicle to control the direction and speed of the vehicle (e.g., to perform collision avoidance with respect to one or more objects detected using information received from the LIDAR system 236). The vehicle control module 272 may use at least one of the range data or the speed data (including the direction data) determined using the LIDAR system 236 to control the operation of the processing system 250. The high-resolution Doppler LIDAR uses a scanning beam 252 that sweeps from side to side, represented by the future beam 253, through an azimuth field of view 254, and through the vertical angle of the spot of light that illuminates the surroundings of the vehicle 238. In some embodiments, the field of view is 360 degrees in azimuth. In some embodiments, scanning optics 218 including oscillating scanning elements 226 and / or unidirectional scanning elements 228 can be used to scan a beam through an azimuth field of view 254 or through a vertical angle. In one embodiment, the oblique angle field of view is 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 within a 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 method of scanning pattern of coherent LIDAR system

[0113] Figure 6 6 is a flow chart illustrating an example method 600 for optimizing a scanning pattern of a LIDAR system. In one embodiment, the method 600 is used to optimize a scanning pattern of a light 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, the method 600 is used to optimize a scanning pattern of a LIDAR system mounted on an autonomous vehicle. Figure 6 For the purpose of explanation, the steps are depicted as overall steps in a specific order, but one or more steps or parts thereof may be performed in a different order, or overlap in time, serially or in 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 polygonal deflector 404 is rotated about a first axis by a motor. In one embodiment, in step 601, the polygonal deflector 501 is rotated about an axis 540 with a motor 534. In one embodiment, in step 601, one or more signals are transmitted to the motors 232, 534 to rotate the polygonal deflectors 404, 501, wherein the signals include data indicating one or more values ​​of a parameter of the rotation (e.g., a value of a rotation speed, a direction of a rotation speed, a duration of rotation, etc.).

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

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

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

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

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

[0120] In step 613, the collimated light beam 580'"' incident on the face 506 is refracted by the face 506 as a light beam 512 into a first plane 541 orthogonal to the rotation axis 542 from a first angle to a second angle defining a field of view 510 within the plane 541. In one embodiment, the field of view 510 is defined by the collimated light beam 580'"' passing from one side of the face 506 to the opposite side and ends when the collimated light beam 580'"' crosses a discontinuity in the face 506. In one embodiment, once the collimated light beam 580'"' is transferred to an adjacent face 506, the refracted light beam 512 is rescanned through the field of view 510 within the plane 541. In another embodiment, in step 613, the collimated light beam 580'"' incident on the face 506 is refracted as a light beam 512 into a second plane 543 orthogonal to the first plane 541. In one embodiment, the refraction of the light beam 580''' in the second plane 543 involves an increase in the angular spread 562 of the light beam 512, and / or a refraction of the centerline of the light beam 512 and / or a rotation of the light beam 512 within the plane 543 based on the rotation of the polygonal deflector 501. The polygonal deflector 404 can have a duty cycle greater than 50%, wherein the duty cycle is based on a ratio of a first time based on a refraction step and a second time based on a rotation and shaping step. The duty cycle can be greater than 70%.

[0121] 7. LIDAR systems using multiple scanners

[0122] Systems and methods according to the present disclosure may use multiple scanners so that the output beam can be turned in a greater number of directions, such as to output beams spanning more elevation angles. For example, a LIDAR system may include two concentric polygon scanners with faces having varying tilt angles. The optical component may output a collimated beam refracted from a first polygon scanner to a second polygon scanner, which refracts the beam to output a beam from the LIDAR system. The varying tilt angles of the polygon scanners (which may be rotated relative to each other and the optical component) may result in different elevation angles for the output beam. This may increase the amount of signal information received based on the output beam in a given time period while maintaining a compact form factor of the LIDAR system, such as to determine the distance and velocity of an object, which may be determined from a return beam of an object that reflects or scatters the output beam, such as to improve the signal-to-noise ratio.

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

[0124] The LIDAR system 700 includes a first polygon scanner 704. The first polygon scanner 704 may include a first face 708 around a first rotation axis 702, and a first body 706 outwardly from the first face 708 relative to the first rotation axis 702. For example, Figure 8 , 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 around the first rotation axis 702, such that each first face 708 is connected to two adjacent first faces 708. The first faces 708 may refract a received light beam, thereby changing the angle of the light from the entrance, air-surface interface (e.g., toward the inside) to the exit side of the first face 708 (e.g., toward the outside).

[0125] The number of first faces 708 may be determined based on a variety of 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 may be detected (e.g., a greater number of elevation angles may be used to output the light beam), the size of the first polygon scanner 704 may increase, and the field of view of the first faces 708 may decrease (e.g., the first faces 708 may have a field of view equal to 360 / number of faces, such that Figure 8 The five first faces 708 depicted in FIG. 7 may each have a 72 degree field of view, while the faces of a polygon scanner having three faces may each have a 120 degree field of view), and the number of transitions (e.g., transitions between adjacent first faces 708) may increase. The transitions may reduce the surface area of ​​the first polygon scanner 704 that may be effectively used to output a light beam. The number of first faces 708 may 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 an innermost portion (eg, closest to the first rotation axis 702) to an outermost portion (eg, farthest from the first rotation axis 702) of the first polygon scanner 704. The first maximum thickness 712 may be greater than or equal to 3 mm and less than or equal to 10 mm.

[0127] Further references Figure 7 , the LIDAR system 700 can include a second polygon scanner 720 that can be positioned or located outwardly from the first polygon scanner 704 relative to the first rotation axis 702 (i.e., a face of the second polygon scanner is positioned outwardly from a face of the first polygon scanner). The second polygon scanner 720 can incorporate features of the first polygon scanner 704. A bearing 716 can be positioned between the first polygon scanner 704 and the second polygon scanner 720 so that the first polygon scanner 704 rotates above the second polygon scanner 720. The bearing 716 can be a refractive index fluid bearing.

[0128] The second polygon scanner 720 may include a second face 724 surrounding a second axis of rotation. The second axis of rotation may be the same as (eg, coincident with) the first axis of rotation 702, or may be parallel to (eg, parallel to and spaced apart from) the first axis of rotation 702. Figure 8As depicted in , the second polygon scanner 720 may include five second faces 724a, 724b, 724c, 724d, 724e. The second faces 724 may form a polygonal shape around the second rotation axis so 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, the face-air interface (e.g., outward).

[0129] The number of second faces 724 may be determined based on a variety of 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 may be detected, the size of the second polygon scanner 720 may increase, the field of view of the second faces 724 may decrease, and the number of transitions may increase. The number of second faces 724a may be greater than or equal to three and less than or equal to ten.

[0130] The first surface 708 and the second surface 724 may have a variable angle (eg, a tilt angle) relative to the corresponding first and second rotation axes, which may be used to control the elevation angle of light output by the second surface 724. Fig. 9 As depicted in FIG. 1 , a particular first face 708 of the first polygon scanner 704 may define a first angle 904 of the inward surface 908 relative to the first rotation axis 702, and a particular second face 724 of the second polygon scanner 720 may define a first angle 904 of the outward surface 916 relative to the second rotation axis (e.g., Fig. 9 , coinciding with the first rotation axis 702).

[0131] At least two of the first faces 708 can define first angles 904 that are different from each other. At least two of the second faces 724 can define second angles 912 that are different relative to each other. The order of the angles 904, 912 (e.g., which faces 708, 724 define a particular angle 904, 912) can be varied, such as to balance the mass of the corresponding polygon scanner 704, 720 relative to the corresponding first and second rotation axes. The angles 904, 912 can be greater than or equal to negative twelve degrees and less than or equal to twelve degrees. The angles 904, 912 can be greater than or equal to negative eight degrees and less than or equal to eight degrees (in Fig. 9 In the reference system depicted in FIG. 1 , a negative angle may indicate that the lower edge of the particular first face 708 or the particular second face 724 is outward from the upper edge of the particular first face 708 or the particular second face 724. For example, for Fig. 9 For the particular first face 708 and the particular second face 724 depicted in FIG. 8 , the first angle 904 may be negative four degrees and the second angle 912 may be six degrees.

[0132] Further references Figure 7 , the first polygon scanner 704 and the second polygon scanner 720 can be made of a material that is relatively high in at least one of a refractive index, a transparency (e.g., at a wavelength of light to be refracted and output by the polygon scanners 704, 720, such as a wavelength of about 1500 nm), or an optical quality (e.g., low scattering). The material of the polygon scanners 704, 720 can be selected so that the polygon scanners 704, 720 have the same refractive index. The transparency of the polygon scanners 704, 720 can enable the polygon scanners 704, 720 to operate as a transmissive polygon. The polygon scanners 704, 720 can be made of a polymeric material. The polygon scanners 704, 720 can be made of a material 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 light beam 732 to the first polygon scanner 704. The optical component 728 may collimate the first light beam 732. The optical component 728 may use a laser to output the first light beam 732. The optical component 728 may have a compact form factor to facilitate reducing the size of the LIDAR system 700. The optical component 728 may include one or more lenses or mirrors that may shape the first light beam 732 and control the direction of the first light beam. At least a portion of the optical component 728 may be positioned so that the laser is emitted in the interior 710 of the first polygon scanner 704.

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

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

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

[0137] At least one motor 756 can rotate the first polygon scanner 704 at a first rotation frequency ω1, and can rotate the second polygon scanner 720 at a second rotation frequency ω2. The rotation frequencies ω1, ω2 can be used to control which first face 708 refracts the first beam 732 to output the second beam 736, and which second face 724 refracts the second beam 736 to output the third beam 740. Therefore, the rotation frequencies ω1, ω2 can be used to control the azimuth (based on the angle at which the beams 732, 736 hit the corresponding first face 708 and the second face 724) and the elevation (based on the angles 904, 912) of the third beam 740. The rotation frequencies ω1, ω2 can be controlled so that one of the first polygon scanner 704 or the second polygon scanner 720 turns to a relatively large angle, while the other of the first polygon scanner 704 or the second polygon scanner 720 turns to a relatively small angle (e.g., coarse angle control with one of the scanners 704, 720 and fine angle control with the other of the scanners 704, 720). The second, outward polygon scanner 720 may be controlled to turn at a relatively large angle, which may allow the first, inward polygon scanner 704 to be relatively small and reduce 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 may detect a position (e.g., an 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 provided as part of the 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 the 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 may output at least one position signal regarding the position of at least one of the first polygon scanner 704 or the second polygon scanner 720, and the position signal may be used to control the corresponding rotation frequencies ω1, ω2.

[0139] Fig.10 Describes the first light beam 732 and the second light beam 736 passing through Figure 7 1 and 10. A graph 1000 of azimuth angles θ and elevation angles φ of a third light beam 740 for paths of 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, 720 described in FIG. Rotation of the first polygon scanner 704 and the second polygon scanner 720 causes various combinations 1004 of the first faces 708 and the second faces 724 to interact with light output by the optical component 728 to output the third light beam 740 (e.g., a combination of a particular first face 708 that refracts the first light beam 732 and a particular second face 724 that refracts the second light beam 736, the second light beam 736 corresponding to the first light beam 732 refracted by the particular first face 708). The combinations 1004 of the first face 708 and the second face 724 can cause various azimuth angles θ and elevation angles φ of the third light beam 740. Combination 1004 may consist of discrete azimuth and elevation angles and may vary within a range of azimuth angles.

[0140] Fig.11 A method 1100 of operating a LIDAR system is depicted. The method 1100 may be performed using various devices and systems described herein, including but not limited to the LIDAR system 700.

[0141] At 1105, a first polygon scanner is rotated about a first rotation axis at a first rotation frequency. The first polygon scanner may include a plurality of first faces, and the plurality of first faces 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, a second polygon scanner is rotated about a second rotation axis at a second rotation frequency, and the second rotation axis can be aligned with the first rotation axis. The second polygon scanner can be outward from the first polygon scanner. The second polygon scanner can include a plurality of second faces, and the plurality of second faces 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, a first light beam is emitted to a specific first surface among the plurality of first surfaces within the first polygon scanner. The first light beam may be emitted by an optical component that outputs the first light beam as a collimated light beam. For example, the optical component may include a laser source and may include various mirrors and lenses that may direct the first light beam to the specific first surface and shape it.

[0144] The specific first facet may refract the first light beam (e.g., based on the refractive index of the first polygon scanner relative to the air inside the first polygon scanner) to output the second light beam to the specific second facet of the second polygon scanner. The specific second facet may 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) to output the third light beam. The azimuth angle of the third light beam may be controlled based on the rotational position of the polygon scanner relative to the rotational axis and the direction of the first light beam. The elevation angle of the third light beam may be controlled based on the rotational position of the polygon scanner relative to the rotational axis and the direction of the first light beam, because the elevation angle may be controlled using the tilt angles of the specific first facet and the specific second facet.

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

[0146] At least one of a distance to the object or a speed of the object is determined using the fourth light beam at 1125. For example, the detector array may generate a signal representative of the fourth light beam, which may be processed to determine at least one of the distance or the speed.

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

[0148] 8. Computing Hardware Overview

[0149] Fig.121 is a block diagram illustrating a computer system 1200 that can be used to perform various operations described herein. The computer system 1200 includes a communication mechanism such as a bus 1210 to transfer information between other internal and external components of the computer system 1200. Information is represented as a physical signal of a measurable phenomenon, usually a voltage, but in other embodiments includes phenomena such as magnetic, electromagnetic, pressure, chemical, molecular atomic, and quantum interactions. For example, a north-south magnetic field, or a zero and non-zero voltage, represents two states (0,1) of a binary digit (bit). Other phenomena can represent numbers of higher cardinality. A superposition of multiple simultaneous quantum states before measurement represents a quantum bit (qubit). A sequence of one or more digits constitutes digital data used to represent a number or code for a character. In some embodiments, information referred to as analog data is represented by a near continuum of measurable values ​​within a specific range. The computer system 1200, or a portion thereof, constitutes a device for performing one or more steps of one or more methods described herein.

[0150] The sequence of binary digits constitutes digital data for representing the number or code of a character. The bus 1210 includes many parallel information conductors so that information can be quickly transmitted between devices coupled to the bus 1210. One or more processors 1202 for processing information are coupled to the bus 1210. The processor 1202 performs a set of operations on the information. The set of operations includes bringing information from the bus 1210 and placing information on the bus 1210. The set of operations also typically includes comparing two or more information units, moving the position of information units, and combining two or more information units, such as by addition or multiplication. The sequence of operations to be performed by the processor 1202 constitutes a computer instruction.

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

[0152] Information, including instructions, is provided to the bus 1210 for use by the processor from an external input device 1212, such as a keyboard containing alphanumeric keys operated by a human user, or a sensor. The sensor detects conditions in its vicinity and converts those detections into signals compatible with the signals used to represent information in the computer system 1200. Other external devices coupled to the bus 1210, primarily for interaction with humans, include: a display device 1214, such as a cathode ray tube (CRT) or a liquid crystal display (LCD), for presenting images; and a pointing device 1216, such as a mouse or trackball or cursor direction keys, for controlling the position of a small cursor image presented on the display 1214 and issuing commands associated with graphical elements presented on the display 1214.

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

[0154] The computer system 1200 also includes one or more instances of a communication interface 1270 coupled to the bus 1210. The communication interface 1270 provides a bidirectional communication coupling to various external devices (such as printers, scanners, and external disks) that operate with their own processors. Generally speaking, the coupling is to a network link 1278, which is connected to a local area network 1280, to which various external devices with their own processors are connected. For example, the communication interface 1270 may be a parallel port or a serial port or a universal serial bus (USB) port on a personal computer. In some embodiments, the communication interface 1270 is an integrated services digital network (ISDN) card or 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, the communication interface 1270 is a cable modem that converts signals on the bus 1210 into signals for communication connections via coaxial cables, or into optical signals for communication connections via fiber optic cables. As another example, the communication interface 1270 can be a local area network (LAN) card to provide a data communication connection to a compatible LAN, such as Ethernet. Wireless links can also be implemented. Carrier waves (such as sound waves and electromagnetic waves), including radio, optical and infrared waves, travel through space without wires or cables. Signals include artificial changes in the amplitude, frequency, phase, polarization or other physical properties of the carrier. For wireless links, the communication interface 1270 sends 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 the 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 or magnetic disks, such as storage device 1208. Volatile media include, for example, dynamic memory 1204. Transmission media include, for example, coaxial cables, copper wire, 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 the processor 1202, except for transmission media.

[0156] Common forms of computer-readable media include, for example, floppy disks, flexible disks, hard disks, magnetic tapes or any other magnetic media, compact disk ROMs (CD-ROMs), digital video disks (DVDs) or any other optical media, punch cards, paper tapes or any other physical media with patterns of holes, RAM, programmable ROMs (PROMs), erasable PROMs (EPROMs), FLASH-EPROMs or any other memory chips or cartridges, 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 that participates in providing information to processor 1202, except carrier waves and other signals.

[0157] 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] The network link 1278 typically provides information communication through one or more networks to other devices that use or process the information. For example, the network link 1278 can provide a connection to a host computer 1282 or to equipment 1284 operated by an Internet Service Provider (ISP) through a local area network 1280. The ISP equipment 1284 in turn provides data communication services through the public, worldwide packet-switched communications network of the network now commonly referred to as the Internet 1290. Computers called servers 1292 connected to the Internet provide services in response to information received through the Internet. For example, the server 1292 provides information representing video data for presentation on the display 1214.

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

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

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

[0162] Fig.13 Chip set 1300 is shown. Chip set 1300 is programmed to perform one or more steps of the methods described herein and includes, for example, Fig.12 The processor and memory components described 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, size retention, and / or limitation of electrical interactions. It is contemplated that in some embodiments, the chipset can be implemented in a single chip. Chipset 1300 or a portion thereof constitutes a means for performing one or more steps of the methods described herein.

[0163] In one embodiment, the chipset 1300 includes a communication mechanism such as a bus 1301 for passing information between components of the chipset 1300. The processor 1303 has connectivity to the bus 1301 to execute instructions and process information stored in, for example, a memory 1305. The processor 1303 may include one or more processing cores, each of which is configured to execute independently. A multi-core processor enables multi-processing within a single physical package. Examples of multi-core processors include two, four, eight or more processing cores. Alternatively or in addition, the processor 1303 may include one or more microprocessors configured in series via the bus 1301 to enable independent execution of instructions, pipelining and multithreading. The 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. The DSP 1307 is typically configured to process real-world signals (e.g., sound) in real time independently of the processor 1303. Similarly, ASIC 1309 can be configured to perform specialized functions not easily performed by a general purpose processor. Other specialized components that aid 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] The processor 1303 and accompanying components have connectivity to the memory 1305 via the bus 1301. The memory 1305 includes both dynamic memory (e.g., RAM, magnetic disk, writable optical disk, 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. The memory 1305 also stores data associated with or generated by the execution of one or more steps of the methods described herein.

[0165] Now that some illustrative embodiments have been described, it is apparent that the foregoing, which has been presented as examples, is illustrative rather than restrictive. In particular, although many of the examples presented herein relate to specific combinations of method behaviors or system elements, those behaviors and those elements may be combined in other ways to accomplish the same goals. The behaviors, elements, and features discussed in relation to one embodiment are not intended to be excluded from similar effects in other embodiments or multiple embodiments.

[0166] The words and terms used herein are for descriptive purposes and should not be considered limiting. As used herein, "including...", "comprising...", "having...", "containing...", "involving...", "characterized by..." and variations thereof are intended to include the items listed thereafter, their equivalents and additional items, and alternative embodiments consisting of the items listed thereafter. In one embodiment, the systems and methods described herein consist of one, more than one in each combination, or all of the elements, actions, or components described.

[0167] Any reference to the embodiments or elements or actions of systems and methods referred to herein in the singular may also encompass embodiments including a plurality of these elements, and any reference to any embodiments or elements or actions referred to herein in the plural may also encompass embodiments including only a single element. References in singular or plural form are not intended to limit currently disclosed systems or methods, their components, actions or elements to singular or plural form. References to any actions or elements based on any information, action or element may include embodiments in which the action or element is based at least in part on any information, action or element.

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

[0169] Where a technical feature in the drawings, detailed description or any claim is followed by a reference numeral, the reference numeral has been included to increase the intelligibility of the drawings, detailed description and claims. Thus, neither the reference numeral nor its absence has any limiting effect on the scope of any claim element.

[0170] The system and method described herein can be embodied in other specific forms without departing from its characteristics. Further relative parallel, vertical, vertical or other positioning or orientation descriptions include changes within + / -10% or + / -10 degrees of pure vertical, parallel or vertical positioning. References to "approximately", "about", "substantially" or other degree terms include changes from + / -10% of a given measurement, unit or range, unless otherwise clearly indicated. Coupled elements can be electrically, mechanically or physically coupled to each other directly or with intervening elements. Thus, the scope of the system and method described herein is indicated by the appended claims rather than the aforementioned description, and changes within the meaning and scope of the equivalents of the claims are included therein.

[0171] The term "coupled" and variations thereof include two components being directly or indirectly joined to one another. Such joining may be static (e.g., permanent or fixed) or movable (e.g., removable or releasable). Such joining may be achieved by the two components being directly connected or coupled to one another, the two components being coupled to one another using a separate intervening component and any additional intermediate components that are coupled to one another, or the two components being coupled to one another using an intervening component that is integrally formed with one of the two components as a single, one-piece body. If "coupled" or variations thereof are modified by additional terms (e.g., directly coupled), the general definition of "coupled" provided above is modified by the plain language meaning of the additional terms (e.g., "directly coupled" refers to the joining of two components without any separate intervening components), resulting in a narrower definition than the general definition of "coupled" provided above. Such coupling may be mechanical, electrical, or fluidic.

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

[0173] Modifications of the described elements and behaviors, such as changes in size, dimensions, structure, shape and proportion of various elements, values ​​of parameters, mounting arrangements, use of materials, colors, orientations may occur without substantially departing from the teachings and advantages of the subject matter disclosed herein. For example, elements 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 changed or varied. Other substitutions, modifications, changes 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 the present disclosure.

[0174] References to element positions herein (e.g., "top," "bottom," "above," "below") are only used to describe the orientation of the various elements in the figures. It should be noted that the orientation of the various elements may be different according to other illustrative embodiments, and such variations are intended to be encompassed by the present disclosure.

Claims

1. Light Detection and Ranging (LIDAR) sensor system, including: a first polygon scanner comprising a plurality of first faces arranged about an axis of rotation; a second polygon scanner comprising a plurality of second faces arranged about the axis of rotation; an optical component configured to output a first light beam to the first polygon scanner, the first polygon scanner configured to refract the first light beam to output a second light beam to the second polygon scanner, the second polygon scanner 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 to rotate the second polygon scanner about the rotation axis.

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

3. The LIDAR sensor system according to claim 2, wherein: The first angle is between approximately negative twelve degrees and approximately twelve degrees.

4. The LIDAR sensor system according to claim 2, wherein: A third angle of the third light beam corresponds to the first angle and the second angle.

5. The LIDAR sensor system according to claim 1, wherein: The optical component is positioned in a space formed between the plurality of first faces through which the rotation axis extends, and the first polygon scanner is between the optical component and the second polygon scanner.

6. The LIDAR sensor system according to claim 1, wherein: The first polygon scanner includes a first body, and the plurality of first faces are on an inner side of the first body facing the rotation axis.

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

8. The LIDAR sensor system according to claim 1, wherein: The optical component is configured to collimate the first light beam.

9. The LIDAR sensor system according to claim 1, wherein: The optical components include at least one mirror for directing the first light beam to the first polygon scanner.

10. The LIDAR sensor system according to claim 1, wherein: A first refractive index of the first polygon scanner is the same as a second refractive index of the second polygon scanner.

11. The LIDAR sensor system according to claim 1, wherein: The plurality of first surfaces include greater than or equal to three and less than or equal to ten first surfaces.

12. The LIDAR sensor system of claim 1, wherein: The first polygon scanner and the second polygon scanner each include a polymeric material.

13. An autonomous vehicle control system comprising: LIDAR sensor, the LIDAR sensor comprising: a first polygon scanner comprising a plurality of first faces arranged about an axis of rotation; a second polygon scanner comprising a plurality of second faces arranged about the axis of rotation; at least one motor configured to rotate the first polygon scanner about the rotation axis and to rotate the second polygon scanner about the rotation axis; a detector array; and One or more processors configured to: causing the at least one motor to rotate the first polygon scanner at a first rotational frequency; causing the at least one motor to rotate the second polygon scanner at a second rotational frequency; causing a laser source to emit a first light beam to a specific first face among the plurality of first faces inside the first polygon scanner, so that the specific first face refracts the first light beam to output a second light beam incident on a specific second face among the plurality of second faces, and the specific second face refracts the second light beam to output a third light beam; receiving a signal from the detector array based on a fourth light beam received at the detector array from an object responsive to the third light beam; and Using the signals received from the detector array, the distance to the object is determined.

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

15. The autonomous vehicle control system of claim 13, wherein: The plurality of first faces include greater than or equal to three and less than or equal to ten faces, and the plurality of second faces include greater than or equal to three and less than or equal to ten faces.

16. An autonomous vehicle comprising: LIDAR sensor, the LIDAR sensor comprising: a first polygon scanner including a plurality of first faces arranged around a rotation axis, wherein a specific first face of the plurality of first faces is configured to refract the first light beam to output a second light beam; a second polygon scanner including a plurality of second faces arranged around the rotation axis, wherein a specific second face of the plurality of second faces is configured to refract the second light beam to output a third light beam; at least one motor configured to rotate the first polygon scanner about the rotation axis and to rotate the second polygon scanner about the rotation axis; and One or more processors configured to: determining a distance to an object using a fourth light beam resulting from at least one of reflection or scattering of the third light beam by the object; and The distance to the object is used to control operation of the autonomous vehicle.

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

18. The autonomous vehicle of claim 16, wherein: The first polygon scanner includes a first body, and the plurality of first faces are on an inner side of the first body facing the rotation axis.

19. The autonomous vehicle of claim 16, wherein: The plurality of first surfaces include greater than or equal to three and less than or equal to ten surfaces.

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