Systems, devices, and methods for improving the imaging performance of a LIDAR system

Abstract

The present invention provides a system for three-dimensional distance mapping of an object, the system comprising a light detection and ranging (LIDAR) system, the LIDAR system including an array of beam emitters, at least one detector element, and a computing unit, the computing unit being configured to: instruct the beam emitters to simultaneously emit emission beams; embed ranging information in the emission beams; use unique orthogonal waveforms to identify the respective emission beams; cause the unique orthogonal waveforms in each of the reflected beams received at each detector element to be automatically associated with the unique orthogonal waveforms in the emission beams so as to provide emission and reflected beam pairs; determine the time of flight of each emission and reflected beam pair; and determine the distance from the time of flight.

Description

[0001] Cross - reference to related applications

[0002] This invention claims priority to U.S. Patent Application No. 62643171, filed on March 15, 2018, with the title SYSTEM, APPARATUS, AND METHOD FOR IMPROVING PERFORMANCE OF IMAGING LIDAR SYSTEMS, which is hereby incorporated by reference in its entirety, including all tables, figures, and claims. Technical field

[0003] The technology of the present invention relates to a light detection and ranging system, in which a plurality of light sources can simultaneously emit light beams and distinguish between them. More specifically, it is a system in which each light beam is encoded by a code dedicated to that light beam, the light beam is automatically associated when it returns to the system, and the light beam is identified in order to calculate the flight time of the light beam and determine the distance. Background art

[0004] LIDAR (Light Detection and Ranging) is a remote sensing method that uses light in the form of pulsed lasers to measure the distance (variable distance) to an object. An imaging LIDAR system is a system in which a distance image is obtained from an object in the LIDAR's field of view. The image synthesized by this system is very similar to a typical image or picture, but instead of having light intensity values in a representation value array, the distance from the LIDAR system is the representation value. The main focus of some LIDAR systems is ADAS (Advanced Driver Assistance System), which is used for vehicle collision avoidance, navigation, and safety systems, and it determines the distance of an object from the vehicle.

[0005] ADAS has various configurations. One type is a scanning system that operates by generating horizontal fan - shaped light beams from multiple laser sources, which are turned on and off in chronological order. The horizontal fan - shaped light beams sequentially scan the entire scene vertically. The time between the time when the probe laser beam is emitted and the time when the reflected laser beam is received at the receiver after being reflected from an object located in the scene is measured, and this time is proportional to the distance between the reflecting object and the LIDAR system. A major drawback of this system is that since the reflected laser beams are received at different times due to sequential scanning, the distance information for the entire scene is obtained at different times. This non - simultaneity can lead to inaccurate results, incorrect motion prediction within the scene, and object deformation (resulting in misidentification).

[0006] Other systems apply wavelength division multiplexing by using laser sources of different wavelengths. This system requires the receiver to be able to distinguish different laser light sources based on wavelength, which in turn requires a single detector and a discrimination filter for each wavelength. This increases the complexity of the optical structure.

[0007] U.S. Patent 7969558 discloses a LIDAR-based 3D point cloud measurement system and method. An example system includes a base, a housing, a plurality of photon emitters and photon detectors contained within the housing, a rotation motor for rotating the housing about the base, and a communication component capable of transmitting signals generated by the photon detectors to an external component. The rotating component includes: a rotating power connector configured to supply power to the rotation motor from an external source; a photon emitter; and a photon detector. In another embodiment, each pair of photon emitter and detector maintains a fixed relationship with each other. In still another embodiment, a single detector "shares" among multiple lasers by focusing multiple detection regions on a single detector or by using a single larger detector. In this system, the lasers must be fired one at a time to ensure there is no ambiguity as to which laser is being fired. There is no automatic association. It is also taught to stay away from using "flash LIDAR", pointing out problems associated with it, including the need for a two-dimensional focusing plane array.

[0008] U.S. Patent Application 20130044310 discloses a system and method for detecting the distance to an object. The method includes providing an illumination system having at least one pulse-width modulated visible light source for illuminating a field of view; emitting an illumination signal using the visible light source at time t for illuminating the field of view for a duration y; integrating the reflected energy in a first time period from time t - x to time t + x; determining a first integration value in the first time period; integrating the reflected energy in a second time period from time t + y - x to time t + y + x; determining a second integration value in the second time period; calculating the difference between the first integration value and the second integration value; determining a propagation delay value proportional to the difference; and determining the distance to the object from the propagation delay value. In this system, the lasers must be fired one at a time to ensure there is no ambiguity as to which laser is being fired. There is no automatic association to enable simultaneous reception.

[0009] U.S. Patent Application 20170090031 discloses a system, method, and processor-readable medium for spatial profiling. In one configuration, the system includes: a light source configured to provide emitted light having at least one time-varying attribute at a selected one of a plurality of wavelength channels, the at least one time-varying attribute including (a) an intensity profile that varies over time and (b) a frequency deviation that varies over time; a beam director configured to spatially direct the emitted light along one of a plurality of directions in two dimensions into an environment having a spatial profile, one of the plurality of directions corresponding to the selected one of the plurality of wavelength channels; a light receiver configured to receive at least a portion of the emitted light reflected by the environment; and a processing unit configured to determine at least one feature associated with at least one time-varying attribute of the reflected light at the selected one wavelength for estimating the spatial profile of the environment associated with the respective one direction. The focus of this technology is to suppress unwanted signals from the environment. Compared with existing systems, the disclosed method requires increased complexity and cost. In this system, the lasers must be fired one at a time to ensure there is no ambiguity as to which laser is being fired. There is no automatic association to enable simultaneous reception.

[0010] There is a need for a system and method for improving the performance of a LIDAR system. Preferably, the system improves range resolution and range update rate while using an existing LIDAR electro-optical system. Even more preferably, the laser sources operate simultaneously, resulting in simultaneous acquisition of range information from reflected beams. It is also preferred that the system distinguishes between reflected beams. It is further preferred that the system and method improve local velocity flow estimation, reduce power consumption, and increase eye safety of the laser sources in the optics of an ADAS. Most preferably, there is an association-based scheme that reduces opto-electronic complexity and the number of components. Summary of the Invention

[0011] The technology of the present invention is a system and method for improving the performance of an existing LIDAR system. The system improves range resolution and range update rate while using an existing LIDAR electro-optical system. In one example, the laser sources in the system are arranged in a vertical array and operate simultaneously, resulting in simultaneous acquisition of range information from reflected beams. The system distinguishes incident reflected beams. The system and method improve local velocity flow estimation, reduce power consumption, and increase eye safety of the laser sources in the optics of an ADAS. The technology of the present invention is an association-based scheme that reduces opto-electronic complexity and the number of components.

[0012] In one embodiment, a system for three-dimensional distance mapping of an object is provided. The system includes a light detection and ranging (LIDAR) system, which includes an array of beam emitters, at least one detector element, and a computing unit. The computing unit is configured to: instruct the beam emitters to simultaneously emit emission beams; embed ranging information in the emission beams; use unique orthogonal waveforms to identify the respective emission beams; cause the unique orthogonal waveforms in each of the reflected beams received at each detector element to be automatically associated with the unique orthogonal waveforms in the emission beams, so as to provide emission and reflected beam pairs; determine the time of flight of each emission and reflected beam pair; and determine the distance from the time of flight.

[0013] In the system, the unique orthogonal waveform can be a Hadamard code.

[0014] In the system, the embedded ranging information can be a pseudo-noise (PN) pulse train.

[0015] In the system, the PN pulse train can be transformed using a Hadamard code.

[0016] In the system, the computing unit can include a correlator for each beam emitter, and the correlator is configured to cause the unique orthogonal waveforms in each of the reflected beams received at each detector element to be automatically associated with the unique orthogonal waveforms in the emission beams.

[0017] In the system, the beam emitter can be a laser beam emitter.

[0018] In another embodiment, a system for three-dimensional distance mapping of an object is provided. The system includes: a computing device, which includes a microprocessor, a timer, and a memory. The timer is configured to determine the time of flight, and the memory is configured to instruct the microprocessor; an array of light sources, which is under the control of the microprocessor and is configured to emit a plurality of emission beams; a ranging information embedder, which is under the control of the microprocessor, and the ranging information embedder is configured to embed the plurality of emission beams; a plurality of orthogonal waveform generators, which are under the control of the microprocessor and are configured to embed a specific orthogonal waveform related to a specific light source into the plurality of emission beams, so that a specific emission beam is embedded with a specific orthogonal waveform; a plurality of detector elements, which are configured to receive a plurality of focused beams; a plurality of correlators, which are under the control of the microprocessor and are configured to associate a specific received beam with a specific emission beam. The correlator corresponds to each light source and communicates with the timer.

[0019] In the system, the orthogonal waveform generator can be a Hadamard generator.

[0020] In the system, the ranging information embedder can be a PN pulse train generator.

[0021] In this system, the light source array can be a linear array.

[0022] In this system, the linear array can be a vertical linear array.

[0023] In this system, the beam emitter can be a laser beam emitter.

[0024] In this system, the detector element can be in a horizontally arranged detector.

[0025] In another embodiment, a computing unit for use with a LIDAR system is provided. The LIDAR system includes an array of beam emitters and at least one detector element. The computing unit is configured to: instruct each beam emitter in the beam array to simultaneously emit an emission beam; cause each emission beam to be embedded with ranging information; use unique orthogonal waveforms to identify each emission beam; cause the unique orthogonal waveforms in each reflected beam to match the unique orthogonal waveforms in the emission beams; and determine distances from the time-of-flight of each emission and reflected beam.

[0026] In another embodiment, a system for three-dimensional distance mapping of an object is provided. The system includes a LIDAR system that includes: an array of beam emitters, each beam emitter emitting an emission signal; at least one detector element for receiving a received signal; a circuit control block; a transmission computing unit that is under the control of the circuit control block; and a reception computing unit that is under the control of the circuit control block. The transmission computing unit is configured to instruct the beam emitters to simultaneously emit emission signals and cause the emission signals to be embedded with ranging information. The transmission computing unit includes a specific computing system for each beam emitter. The receiver computing system is configured to: use unique orthogonal waveforms to identify each emission signal; cause the unique orthogonal waveforms in each received signal to match the unique orthogonal waveforms in the emission signals; and determine distances from the time-of-flight of each emission and reception pair.

[0027] In this system, the transmission computing unit can include a PN pulse train generator to cause the emission beam to be embedded with ranging information.

[0028] In this system, the computing system can include a Hadamard generator to use unique orthogonal waveforms to identify the emission signals.

[0029] In another embodiment, a method for three-dimensional distance mapping of an object is provided, the method comprising: selecting a LIDAR system, the LIDAR system comprising: an array of beam emitters, each beam emitter emitting an emission signal; at least one detector element for receiving a reception signal; and a calculation unit, the calculation unit comprising a specific calculation system for each beam emitter, the calculation unit:

[0030] Instructing the beam emitters to simultaneously emit emission signals;

[0031] Causing the emission signals to be embedded with ranging information;

[0032] Using unique orthogonal waveforms to identify each emission signal;

[0033] Causing the unique orthogonal waveforms in each reception signal to match the unique orthogonal waveforms in the emission signals; and

[0034] Determining the distance from the time of flight of each emission and reception signal.

[0035] In this method, the embedded ranging information may be an embedded pseudo-noise (PN) pulse train.

[0036] In this method, using unique orthogonal waveforms to identify each emission signal may include using unique Hadamard codes to identify each emission signal.

[0037] The method may include converting the PN pulse train with Hadamard codes.

[0038] In a system embodiment having an array of multiple lasers, the system:

[0039] - Assigns unique identifiers to each laser to be emitted from the laser array;

[0040] - Simultaneously emits multiple lasers from the array, each laser containing a unique identifier through encoding (emission). The laser hits an object and reflects back towards the device containing the array and the system;

[0041] - Receives the signals associated with each emission signal, simultaneously (receiving);

[0042] - Distinguishes each signal according to the unique identifier assigned to each signal at the time of emission;

[0043] - Measures the time delay between the emission and reception of each unique signal at the device containing the system and the array;

[0044] - Determines the distance of the object based on the time delay between all emission and reception signals distinguished by using the identifiers. Description of the Drawings

[0045] Figure 1 It is a schematic diagram of the optical system of the technology of the present invention, showing light emission.

[0046] Figure 2 It is a schematic diagram of the optical system of the technology of the present invention, showing light reception.

[0047] Figure 3 It is a schematic diagram showing a linear array of a laser emitter and a diverging lens, showing light emission and reflection.

[0048] Figure 4 It is a schematic diagram showing a focusing lens and a linear array detector.

[0049] Figure 5 It is a schematic diagram showing the transmitting component of a computing unit.

[0050] Figure 6A It is a block diagram schematically showing the operation of the computing unit during transmission and the components acting during transmission; Figure 6B It is a block diagram schematically showing the operation of the computing unit during reception and the components acting during reception.

[0051] Figure 7 It is a block diagram showing the steps in beam reception and auto-correlation.

[0052] Figure 8 It is a view of a single PN sequence PN burst.

[0053] Figure 9 It is a block diagram showing the steps in encoding and transmitting a light beam.

[0054] Figure 10 It is a schematic diagram showing the receiving component of a computing unit.

[0055] Figure 11 It is a block diagram showing the steps of a method for determining distance and time of flight. Detailed Description of the Invention

[0056] Unless otherwise expressly stated, the following rules of interpretation apply to this specification (written description and claims): (a) All words used herein shall be interpreted as to gender or number (singular or plural) as the circumstances require; (b) The singular forms "a", "an", and "the" used in the specification and the appended claims include the plural, unless the context clearly dictates otherwise;

[0057] (c) The preceding term "about" applied to a stated distance or value denotes an approximation within the deviation of the distance or value known or expected in the art of the measuring method; (d) The words "herein", "here", "above", and "below" and words of similar import refer to the entire specification and not to any particular paragraph, claim, or subpart thereof unless otherwise specified; (e) Descriptive headings are for convenience only and should not control or affect the meaning or construction of any part of the specification; and (f) "Or" and "any" are not exclusive, and "comprising" and "including" are not restrictive. Moreover, otherwise the terms "comprising", "having", "including" shall be construed as open-ended terms (i.e., meaning "including but not limited to") unless otherwise specified.

[0058] The recitation of numerical ranges herein is merely a shorthand method of indicating individually each and every value falling within the range unless otherwise indicated herein, and each and every such individual value is incorporated into the specification as if it were individually recited herein. When a specific range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit (unless the context clearly dictates otherwise), between the upper and lower limits of that range and any other stated or intervening value in that stated range is included therein. All smaller subranges are also included. The upper and lower limits of these smaller ranges are also included therein, subject to any explicit exclusionary limitations stated in the range.

[0059] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the relevant art. Although any methods and materials similar or equivalent to those described herein can also be used, the acceptable methods and materials are described below.

[0060] Figure 1 The optical system generally designated 8 as shown includes an exemplary linear array of light sources 12, 14, 16, 18 generally designated 10. Although four light sources are shown, there can be a plurality of light sources. The light sources can be, for example but not limited to, laser light sources or light emitting diodes. Each light source 12, 14, 16, 18 emits an emission beam 32, 34, 36, 38, and the emission beams 32, 34, 36, 38 pass through a diverging lens 40 and produce planar, horizontal fan-shaped detection beams 42, 44, 46, 48 (referred to as detection beams). In an embodiment, the linear array 10 is a vertical linear array. The light sources 12, 14, 16, 18 are positioned relative to the diverging lens 40 such that each emission beam 32, 34, 36, 38 is refracted at a different angle 50 from the other beams in the array 10, thereby causing each detection beam 42, 44, 46, 48 to impinge on different portions of an object 52. As Figure 2As shown, the reflected light beams 52, 54, 56, 58 from the object 52 pass through the focusing lens 60, where they are focused into focused light beams 62, 64, 66, 68, and then the focused light beams 62, 64, 66, 68 impinge on the detector 70. An embodiment of the focusing lens is an astigmatic optical system. The reflected light beams 52, 54, 56, 58 and the focused light beams 62, 64, 66, 68 are planar, horizontal fan-shaped light beams.

[0061] As Figure 3 shown, using a probe light beam as an example, the probe light beam 42 is reflected from the first object 51 so as to become the first reflected light beam 52 (54, 56, 58 are the reflected light beams corresponding to the probe light beams 42, 44, 46, 48, but are omitted from the figure for clarity). In fact, there are multiple received signals (the received signals include reflected light beams and focused light beams), and they are all focused on a detector element 92, so that the received signals at multiple distances are confused with the received signals at multiple heights. The probe light beam 42 is reflected from the second object 53 to become the second reflected light beam 72 (74, 76, 78 are the second reflected light beams corresponding to the probe light beams 42, 44, 46, 48, but are omitted from the figure for clarity). The first object 52 is closer to the linear array 10 than the second object 53, so the flight time of the first reflected light beam 52 is shorter than the flight time of the second reflected light beam 72.

[0062] The detector 70 is shown in Figure 4 . The receiving optics are arranged to receive a horizontal fan-shaped light beam because it has a linear array of detector elements 92, 94, 96, which are collectively referred to as 90. Figure 4 Three detector elements are shown in, however, those skilled in the art should understand that there can be no more than three. The detector 70 receives light beams from any vertical range and maps them onto the linear array 90, so that regardless of the vertical displacement of the probe light beam, the focused light beam will always impinge on the detector 70. The horizontal positions will be different because there are detector elements 92, 94, 96 at each horizontal position, and the lens 60 images the reflected light from the object onto the array 90.

[0063] The combination of the vertical positioning of the linear array 10 of the light sources 12, 14, 16, 18 and the horizontal resolution of the detector 70 (the linear array 90 having its detector elements 92, 94, 96) enables people to calculate a two-dimensional array of distance values. Since the light sources operate simultaneously, a two-dimensional array of distance values is obtained simultaneously.

[0064] Figure 5Represents the transmitter component of the optical system 8. It includes a control circuit block 111 and emission calculation units 132, 134, 136, 138, which are all the elements in the figure except for the light sources 12, 14, 16, 18 and the lens 40. The control circuit block 111 includes a computing device 100, which can be a silicon chip or a field-programmable gate array (FPGA). The computing device 100 may include a microprocessor 102 and a memory 104, and the memory 104 is arranged to instruct the microprocessor 102. The computing device 100 further includes a clock generator 106, which is electrically connected to the transmitter line 108 and the receiver line 110 (see Figure 10 ) in the control circuit block 111. The control circuit block 111 controls the emission calculation units 132, 134, 136, 138 and coordinates the transmitter line 108 and the receiver line 110. The control circuit block 111 emits a signal F', which controls the frame timing and the frame update rate. A ranging information embedder (such as the emission pseudonoise generator 113) is in electrical communication with the transmitter circuit 108. It generates a pseudonoise (PN) pulse train. The transmitter circuit 108 is divided into discrete channels 112, 114, 116, 118, where each laser transmitter 12, 14, 16, 18 has a channel. Each channel 112, 114, 116, 118 has a Hadamard code generator 122, 124, 126, 128, which generates a specific (unique) orthogonal Hadamard code to ensure that each laser pulse train can be separated from its neighbors. The channels 112, 114, 116, 118 terminate at the light sources 12, 14, 16, 18. The Hadamard code family is used to modulate the PN code, and the subsequent pulse train is used to drive the light sources 12, 14, 16, 18, which emit encoded signals, thereby creating simultaneously emitted but specifically (uniquely) encoded emission beams 32, 34, 36, 38.

[0065] As Figure 6A shown, when instructed by the memory 104 at 200, the Hadamard code generators 122, 124, 126, 128 encode 202 each emission beam 32, 34, 36, 38 with a beam-specific orthogonal code 142, 144, 146, 148. They are specific identifiers associated with a given light source 12, 14, 16, 18. The emission beams 32, 34, 36, 38 are simultaneously emitted 204 from their respective light sources 12, 14, 16, 18. The emission beams 32, 34, 36, 38 impinge 206 on the lens 40 and are emitted 208 as detection beams 42, 44, 46, 48, which impinge 209 on the objects 52, 54. As Figure 6BAs shown, the probe beams 24, 44, 26, 48 are reflected 210 as reflected beams 52, 54, 56, 58. The reflected beams 52, 54, 56, 58 are focused 212 by the lens 60 into focused beams 62, 64, 66, 68 and received 214 by the detector 70. Specific codes or modulations 142, 144, 146, 148 are maintained 206 encoded in the probe beams 42, 44, 46, 48, the reflected beams 52, 54, 56, 58, the second reflected beams 72, 74, 76, 78, the focused beams 62, 64, 66, 68 and the second focused beams 82, 84, 86, 88. As is known to those skilled in the art, there will be many reflected beams and many focused beams. For clarity, the present invention is merely illustrative and refers to the beams reflected from two different objects. In one embodiment, the generated codes include maximum length pseudo-noise codes orthogonal to Walsh / Hadamard codes (hereinafter referred to as "codes") in order to generate a family of codes (hereinafter referred to as "codebook") as a complete set.

[0066] As Figure 7 shown, the memory 104 instructs 220 the microprocessor 102 to extract 222 specific codes or modulations 142, 144, 146, 148 from the specific focused beams 62, 64, 66, 68 such that the specific codes or modulations 142, 144, 146, 148 from the specific focused beams 62, 64, 66, 68 match (auto-correlate) 224 the specific codes or modulations 142, 144, 146, 148 from the probe beams 42, 44, 46, 48 and to distinguish 226 between multiple pairs of transmitted (transmitted beams 32, 34, 36, 38) and received signals (focused beams 62, 64, 66, 68). The memory 104 instructs the microprocessor 102 to determine 228 the time-of-flight of each pair of transmitted and received signals and to collect 230 distance information. For clarity, the Hadamard generator uses the code 142 to encode the transmitted beam 32. The code 142 returns in the focused beam 62. The Hadamard generator uses the code 144 to encode the transmitted beam 34. The code 144 returns in the focused beam 64. The correlator causes the code 142 encoding the transmitted beam 32 to auto-correlate with the code 142 in the focused beam 62. The correlator causes the code 144 encoding the transmitted beam 34 to auto-correlate with the code 144 in the focused beam 64. This is done for each beam transmitted and received.

[0067] Details of modulation and demodulation can be obtained from Figure 7 and 8 As Figure 8 shown, a single PN sequence PN burst 300 is shown, which is 256 pulses long. -1 indicates when the light source is off.

[0068] The length of the Walsh / Hadamard code is an even power of 2, such as 2 N . The length of the PN m-sequence is a power of 2, 2 N - 1.

[0069] At the position of the longest zero run in the code sequence, additional "zeros" or off states are inserted into the m-sequence so that the length of the "padded" m-sequence reaches 2 N of the length.

[0070] As Figure 9 shown, the memory 104 instructs the Hadamard code generators 122, 124, 126, 128 to encode the 400 PN sequences 300 using Hadamard transforms to provide the 402 Hadamard transform encoded PN sequences 302, 304, 306, 308. Each transmitted light beam 32, 34, 36, 38 is encoded 402 using a different Hadamard transform encoded PN sequence 302, 304, 306, 308. The Hadamard transform causes each transmitted light beam 32, 34, 36, 38 to be modulated by a different waveform. One use of the PN sequence is in ranging applications, so by applying the Hadamard transform encoded PN sequences 302, 304, 306, 308 with different Hadamard codes to each transmitted light beam 32, 34, 36, 38, the transmitted signal and the received signal are sent together with the embedded ranging information. The system 8 is capable of simultaneously transmitting the transmitted signal and receiving the received signal.

[0071] Another benefit of using PN codes is a factor called processing gain; processing gain is produced because over time, multiple samples are reconstructed in a demodulator (which is a correlator) under a demodulation scheme. This demodulation scheme only emphasizes specific patterns and gives them gain (by summing in the correlator), and this gain is related to the processing of the signal, so it is called processing gain. Due to this processing gain, the transmitted light beams 32, 34, 36, 38 can be reduced by a relatively large amount, thus reducing the total transmitted power of all light sources 12, 14, 16, 18, making it safer for the eyes and consuming less power at the same time.

[0072] In one embodiment, there is an inherent pulse repetition rate and an inherent dwell time because the received signal is used for timing the time-of-flight ranging information. By implementing the system 8 at the same inherent pulse repetition rate, but with more pulses in the Hadamard encoded PN sequence, a higher resolution of the distance information is obtained. A longer encoded PN sequence also provides a better distance estimate.

[0073] Figure 10Shows the receiver components of the receiver computing units 432, 434, 436, 438 of the optical system 8. Using the detector element 92 as an example, each detector element 92, 94, 96 has a discrete detector circuit (computing system) 500 (obviously, the detector element is not part of the receiver computing units 432, 434, 436, 438). The detector circuit 500 communicates with a TIA (transimpedance amplifier) 502 (this TIA 502 is not part of the computing unit) and each correlator channel 506, and each correlator channel 506 has its sliding correlator 508. The TIA ensures high-speed operation. The sliding correlator 508 communicates electronically with the Hadamard code generators 122, 124, 126, 128.

[0074] Figure 11 Shows the steps of a method for determining distance and time of flight. The detector detects more than 600 focused light beams and sends 602 an analog signal to an analog-to-digital converter, which digitizes 604 the signal. The digitized signal is copied 606 into each correlator channel. This is because each detector element receives focused light beams from any one or more lasers. Therefore, in order to identify which laser it comes from, the system needs to compare the incoming code with the output code. In each correlator channel, Hadamard codes and PN codes are used to identify 608 the laser that first emits the light beam. They are also used to obtain ranging information. The PN and Hadamard codes are autocorrelated mathematical structures (they are their own reciprocals). This includes the sliding correlator. When the codes are aligned 610, the sliding correlator emits 612 a pulse, which indicates that the codes are aligned. When the codes are not aligned 614, a direct measurement of the time of flight is provided 616, and the distance is directly determined 618. After each correlator, the distance is emitted 620 from each timing comparison block.

[0075] In an alternative embodiment, any waveform family is used to encode the emitted light beam. The waveform is similar to a single noise, each being strongly autocorrelated and not cross-correlated (or orthogonal) with other family members, such as but not limited to Kasami sequences and Golay binary complementary sequences.

[0076] In an alternative embodiment, the light source array is not a linear array. Similarly, in an alternative embodiment, the array of detector elements is not in the detector. In another embodiment, the array of detector elements and the detector may not be in a linear array, such as but not limited to a circular structure, a rotating array, or a sphere of detector elements.

[0077] Embodiment 1: Spatial Profiling for ADAS

[0078] The main focus of some LIDAR systems is on ADAS (Advanced Driver Assistance Systems) for vehicle collision avoidance, navigation, and safety systems that determine the distance of objects from the vehicle. For example, the system of the present invention is integrated into existing systems such as, but not limited to, the system disclosed in U.S. Patent Application 20170090031. The system of the present invention overcomes the deficiencies in U.S. Patent Application 20170090031 because it reduces the complexity of the system and allows for simultaneous beam emission due to its automatic correlation ability. When viewed from one or more specific projection angles, the spatial profile of the environment is estimated by determining the distance of any reflective surface (such as the distance of an object or obstacle) within the solid angle or field of view at each projection angle. The system can be used to monitor relative motion or changes in the environment.

[0079] In the field of autonomous vehicles (on land, in the air, on water, or in space), the system of the present invention integrated into an existing system is capable of estimating the spatial profile of traffic conditions, including the distance of any object (such as an obstacle or a target ahead), from the projection angles of the vehicle. When the vehicle is in motion, the spatial profile observed from a vehicle at another location can change and can be re-estimated. As another example, in the docking field, the system can estimate the spatial profile of a dock from the projection angles of a ship, such as the proximity of the ship to a specific part of the dock, to facilitate a successful docking without colliding with any part of the dock.

[0080] Example 2: Spatial Profiling for Automated Tasks

[0081] The system of the present invention is integrated into existing systems such as, but not limited to, the system disclosed in U.S. Patent Application 20130044310. The system of the present invention overcomes the deficiencies in U.S. Patent Application 20130044310 because it reduces the complexity of the system and allows for simultaneous beam emission due to its automatic correlation ability. The system of the present invention integrated into an existing system can be used in the fields of industrial measurement and automation, site surveying, security monitoring and surveillance, robotics, and machine vision.

[0082] Example 3: Spatial Profiling for Environmental Monitoring

[0083] The system of the present invention is integrated into existing systems such as, but not limited to, the system disclosed in U.S. Patent 7969558. The system of the present invention overcomes the deficiencies in U.S. Patent 7969558 due to its automatic correlation ability. The system of the present invention integrated into an existing system can be used in the following fields: agriculture and precision forestry, civil engineering and surveying, emergency services, environmental and coastal monitoring, highways and road networks, mining, quarries and aggregates, railway mapping and applications.

[0084] Although example embodiments have been presented with examples that are presently considered to be the most practical and / or suitable, it is to be understood that the specification is not limited to the disclosed embodiments, but on the contrary, will cover various modifications and equivalent structures included within the spirit and scope of the example embodiments. Those skilled in the art will recognize or be able to ascertain many equivalent forms of the specific example embodiments specifically described herein using only routine experimentation. These equivalent forms will be included within the scope of the appended or subsequently presented claims herein.

Claims

1. A system for three-dimensional distance mapping of an object, the system comprising a light detection and ranging LIDAR system, the LIDAR system including a vertical array of beam emitters, a detector element with horizontal resolution having a plurality of detector elements, a diverging lens, a focusing lens, and a computing unit having a transmitting component and a receiving component; the computing unit is configured to: Instruct the beam emitters to simultaneously emit a plurality of transmitted beams; Embed ranging information in each of a plurality of transmitted light beams; wherein, The ranging information includes a pseudo-noise PN pulse train for each of the plurality of transmitted beams; Use unique orthogonal waveforms to identify each of the plurality of transmitted beams to ensure that each of the plurality of transmitted beams has a separable pseudo-noise PN pulse train; Cause the unique orthogonal waveforms in each of the reflected beams received at each detector element to be automatically associated with the unique orthogonal waveforms in the transmitted beams to provide transmitted and reflected beam pairs; Determine the time of flight of each transmitted and reflected beam pair; And Determine the distance from the time of flight; Wherein the combination of the vertical array of beam emitters of the beam emitter and the horizontal resolution of the plurality of detector elements is capable of calculating a two-dimensional array of distance values; and Wherein the receiving component further includes a correlator for each beam emitter for automatically associating the unique orthogonal waveforms in each of the reflected beams received at each detector element with the unique orthogonal waveforms in the transmitted beams.

2. The system according to claim 1, wherein: The unique orthogonal waveforms include Hadamard codes.

3. The system according to claim 1, wherein: The PN pulse train is converted using Hadamard codes.

4. The system according to any one of claims 1 to 3, wherein: The beam emitter includes a laser beam emitter.

5. A system for three-dimensional distance mapping of an object, the system comprising: Computing means, The computing means includes: A microprocessor; A timer configured to determine the time of flight; and A memory configured to instruct the microprocessor; A vertical light source array, the vertical light source array under the control of the microprocessor and configured to emit a plurality of transmitted beams; A ranging information embedder, the ranging information embedder under the control of the microprocessor, the ranging information embedder configured to embed the plurality of transmitted beams with a pseudo-noise PN pulse train; A plurality of orthogonal waveform generators, the orthogonal waveform generators under the control of the microprocessor and configured to embed a specific orthogonal waveform generator associated with a specific light source into the plurality of transmitted beams with a pseudo-noise PN pulse train so that a specific transmitted beam is embedded with a specific orthogonal waveform; A plurality of detector elements with horizontal resolution, the detector elements configured to receive a plurality of focused beams; A plurality of correlators, the correlators under the control of the microprocessor and configured to associate a specific received beam with a specific transmitted beam, the correlators corresponding to each light source and communicating with the timer; A diverging lens; and A focusing lens.

6. The system according to claim 5, wherein: The orthogonal waveform generator includes a Hadamard generator.

7. The system according to claim 5 or 6, wherein: The beam emitter includes a laser beam emitter.

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