DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Arguments
Applicant's arguments filed 03/09/2026 have been fully considered but they are not persuasive.
Regarding Claims 1 and 29, applicant suggests that the combination of FW1 and Wagner would render the device unsatisfactory for its intended purpose and is therefore not an obvious modification. This argument is moot, as Wagner is no longer used to reject this limitation.
Applicant further suggests that FW1 does not teach that the working distance of the disclosed device (20 cm) is greater than the depth resolution, c/B. Examiner notes that any operational optical device should satisfy this limitation. If FW1 designed a microscope in which the depth resolution was greater than the working distance, it would not be functional.
Applicant suggests that FW1 teaches a depth resolution of 7.5 meters, but the cited example is meant to illustrate the increase in measurement speed that can be attained by simultaneously projecting multiple frequencies onto the target. FW1 merely suggests that sampling 20 frequencies simultaneously can decrease the overall sampling time needed to measure a larger set of frequencies. The 40 MHz bandwidth quoted in this passage is the synthetic bandwidth of an individual instance of 20 frequencies simultaneously measured, but does not represent the full bandwidth of the 1000 frequencies mentioned in the text. Furthermore, Figure 6, Figure 10, and Page H60 suggest depth resolutions in the range of microns, not meters.
Regarding Claim 25, the examiner notes that at least Wagner does teach that the beams are mutually coherent, and the rejection has been rewritten to reflect this.
Regarding Claim 26, applicant makes similar arguments to those posed regarding Claim 1. Examiner responds similarly here, noting that a device in which the depth resolution was larger than the distance to the target scene would be inoperable.
Regarding applicant’s second and third points regarding Claim 26, examiner notes that the relevant behavior of Wagner is described in the second paragraph of page two, where the outputs of many scalable tiles are made to interfere on the target, resulting in a disclosed bandwidth of 10 GHz. In this case, c/B is about 3 cm, far less than the distance of the targets suggested in Wagner.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1-2, 4, 8, 10, 15-17, and 29 are rejected under 35 U.S.C. 103 as being unpatentable over Feldkhun et al. (Feldkhun, Daniel, and Kelvin H. Wagner. "Doppler encoded excitation pattern tomographic optical microscopy." Applied optics 49.34 (2010): H47-H63), hereinafter denoted FW1 and in view of Zhang (Zhang et al., "Serpentine optical phased array silicon photonic aperture tile with two-dimensional wavelength beam steering." Optical Fiber Communication Conference 3—7 March 2019).
Regarding Claim 1, FW1 discloses a range-resolved imaging method (H50, Column 2: Moreover, as an alternative to axial sectioning, it is possible to measure 3D structures tomographically…) comprising:
illuminating a scene with a plurality of mutually coherent beams (H55, Column 2: “by coherently combining twenty 2MHz wide FM measurements,”), each propagating at a speed c (e.g., H49 discloses that light is used), to produce a plurality of traveling-wave interference fringes at the scene (H52, Column 1; Figure 8: “white light traveling fringes”, these fringes are produced by the three distinct wavelengths shown in the figure;) each of the plurality of mutually coherent beams being shifted in frequency within a collective bandwidth B (H55, Column 2: “by coherently combining twenty 2MHz wide FM measurements, it is possible to attain a relatively large DOF, maintain the NA and resolution of the full synthetic bandwidth (e.g., 40 MHz)) of the emitter array with frequency spacings between any two of the plurality of mutually coherent beams being substantially non-redundant, such that no two of the frequency spacings are the same (Figure 4 and its caption (c) disclose non-redundant frequency spacing), and said scene being located at a distance substantially greater that c/B from the emitter array (Figure 6, Figure 10, and Page H60 suggest depth resolutions in the range of microns. An optical instrument that did not satisfy this criteria would likely be inoperable.).
detecting a time-varying signal backscattered by the scene in response to illumination by the plurality of mutually coherent beams (H59 Column 1: “collect the fluoresced or scattered light onto a high-speed large-area photodiode”);
extracting amplitudes and phases (H59, Column 1: “The magnitude and phase of the Fourier slice is determined by the envelope and phase of the carrier signal, respectively”) of interferometric temporal beat note oscillation of the time-varying signal (H50 Column 1: "the diffracted wavefronts are made to interfere, producing sinusoidal fringes running across the object), the amplitudes and phases corresponding to selected Fourier components of the scene's spatial Fourier representation (H59, Column 1: “The magnitude and phase of the Fourier slice is determined by the envelope and phase of the carrier signal, respectively”);
and producing a range-resolved image of the scene by applying a complex-valued weight to each of the selected Fourier components and applying a Fourier synthesis method to the weighted Fourier components (H50, Column 2, Section B: “Hence, in analogy to projection tomography, the goal is to synthesize a 2D or 3D image from a series of 1D projections. This can be accomplished using direct Fourier synthesis methods”), the range-resolved image having a transverse resolution substantially determined by a maximum spatial separation between any two of a plurality of emitters, of the emitter array (This is a well-known property of interferometry and synthetic apertures), and a depth resolution that is substantially equal to c/2B and consequently substantially independent of the maximum spatial separation (This property is inherent to synthetic apertures operated in the mode described here).
FW1 does not teach and Zhang does teach wherein each beam corresponds to a respective emitter (Figure 1; Page 2: “As shown in Fig. 1(a), the SOPA beam steers slowly along the x-axis by radiating out of a waveguide-integrated weak grating and quickly along the y-axis by accumulating the (wavelength dependent) propagation phase delay” These indicate one beam emitted from a single SOPA element, which can further be tiled into an array (Page 2, Para 2).).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate the teaching of Zhang to have each beam correspond to a respective emitter into the device of FW1. It is well-known in the LiDAR arts to generate beam arrays with arrays of emitters, as in the SOPA array of Zhang, and a skilled worker would be able to generate multiple beams with this approach with a reasonable expectation of success.
Regarding Claim 2, FW1 further discloses that illuminating the scene comprises:
emitting each of the plurality of mutually coherent beams from a respective one of the plurality of emitters such that, at the scene, each beam of the plurality of mutually coherent beams substantially overlaps with another beam of the plurality of mutually coherent beams, thereby producing interferometric intensity fringes traveling away from the emitter array at the speed c (Figure 2 shows the overlap of beams on the object in the left panel. The right panel shows the traveling fringe intensity at the object).
Regarding Claim 4, FW1 further discloses the plurality of mutually coherent beams being N in number, the selected 3-D Fourier components being as many as N(N-1) in number, and the plurality of traveling- wave interference fringes being as many as N (N - 1)/2 in number (this preamble simply represents the mathematics of how N mutually coherent beams would interfere to yield N(N-1) Fourier components and N(N-1)/2 interference fringes), such that the step of illuminating includes:
illuminating the scene with the N mutually coherent beams simultaneously (Figure 4, caption: FM sampling. The object is illuminated with multiple spatial frequencies to measure multiple samples along a Fourier slice simultaneously, thereby speeding up the measurement), thereby measuring the as many as N(N - 1) 3-D Fourier components in parallel (H41, Column 1: “A portion of the intensity-modulated scattered radiation response due to target motion across each projected pattern is collected by one or more spatially integrating detectors and processed to estimate the corresponding spatial Fourier coefficient of the object”).
Regarding Claim 9, FW1 further discloses extracting amplitudes and phases including extracting, with a temporal Fourier transform, amplitudes and phases of the interferometric temporal beat note oscillation frequencies (H49 Column 1: "the spatially integrated flux scattered, fluoresced, or transmitted by an object in response to a moving sinusoidal intensity pattern will oscillate in time, the amplitude and phase of the oscillation corresponding to the strength and offset of the matching Fourier component present in the object").
Regarding Claim 10, FW1 further discloses the plurality of coherent beams being N in number and each having a respective one of N distinct carrier frequencies fi, f2, ...,fN that are non- redundant (Figure 4c, caption: Nonredundant FM sampling. Since there are no redundant beats in the RF signal, each detected carrier maps to a distinct Fourier sample), such that each frequency difference (fi - fj) between any two of N(N - 1)/2 pairs of carrier frequencies is unique, wherein each of indices i and j is less than or equal to N and i *j (The remaining text in this claim is a description of the mathematical properties of interfering N coherent beams operating at non-redundant carrier frequencies).
Regarding Claim 15, FW1 further discloses further comprising:
illuminating the scene with an additional plurality of mutually coherent beams, which is (b) a second plurality of mutually coherent beams (H55, Column 2: “employing a hybrid sampling approach where a small number of relatively wide frequency bands is measured sequentially. For example, by coherently combining twenty 2MHz wide FM measurements, it is possible to attain a relatively large DOF, maintain the NA and resolution of the full synthetic bandwidth (e.g., 40 MHz), and measure a 1000 frequency Fourier slice 50 times faster than by sequential sampling.”);
detecting an additional time-varying signal, backscattered by the scene in response to illumination by the additional plurality of mutually coherent beams, and including additional interferometric products of multiple pairs of the additional plurality of coherent beams (H59 Column 1: “collect the fluoresced or scattered light onto a high-speed large-area photodiode”; Figure 4c shows the results of a plurality of pairs of coherent beams being interfered with each other);
extracting additional amplitudes and additional phases (H59, Column 1: “The magnitude and phase of the Fourier slice is determined by the envelope and phase of the carrier signal, respectively”) of temporal oscillations of the additional time-varying signal (H50 Column 1: "the diffracted wavefronts are made to interfere, producing sinusoidal fringes running across the object); and
appending the additional amplitudes and additional phases as additional components of the selected Fourier components (Figure 3 caption describes the method of constructing 2D images from 1D slices or 3D images from 2D slices; The smeared backprojections are summed to build up a 2D image in real time, projection by projection. In effect, this discloses that the method of Claim 1 can be repeated an arbitrary number of times, and the results of each iteration can be combined into an image).
Regarding Claim 16, FW1 further discloses that the second plurality of mutually coherent beams being one of (i) a rotated version of the plurality of mutually coherent beams (Figure 3 caption: The acousto-optically diffracted first-order beams are rotated using a prism or other means and projected as plane waves onto the sample; H50, Column 1: Additional Fourier slices can be measured by rotating the object or rotating the illumination pattern using a prism or an arrangement of mirrors).
Regarding Claim 17, which depends from rejected Claim 1, FW1 discloses the plurality of mutually coherent beams with the emitter array, the emitter array being driven by a set signals having non-redundantly spaced frequencies (Figure 4 and its caption (c) disclose non-redundant frequency spacing) spanning the collective bandwidth B (H55, Column 2: “by coherently combining twenty 2MHz wide FM measurements, it is possible to attain a relatively large DOF, maintain the NA and resolution of the full synthetic bandwidth (e.g., 40 MHz)).
Regarding Claim 29, FW1 discloses a range-resolved imaging method (H50, Column 2: Moreover, as an alternative to axial sectioning, it is possible to measure 3D structures tomographically…) comprising:
illuminating simultaneously or sequentially a scene comprising one or more objects with a plurality of pairs of beams (H55, Column 2: “by coherently combining twenty 2MHz wide FM measurements,”), each beam propagating at a velocity c (e.g., H49 discloses that light is used), and shifted in frequency within a collective bandwidth B of the emitter array (H55, Column 2: “by coherently combining twenty 2MHz wide FM measurements, it is possible to attain a relatively large DOF, maintain the NA and resolution of the full synthetic bandwidth (e.g., 40 MHz)), and said scene being located at a distance substantially greater that c/B from the emitter array (Figure 6, Figure 10, and Page H60 suggest depth resolutions in the range of microns. An optical instrument that did not satisfy this criteria would likely be inoperable.).
detecting a time-varying signal backscattered by the objects in response to the illumination by the plurality of pairs of beams (H59 Column 1: “collect the fluoresced or scattered light onto a high-speed large-area photodiode”), the time-varying signal comprising one or more beat oscillations, each beat oscillation being produced by an interference of a pair of beams in the plurality of pairs of beams and having a frequency equal to a difference between the frequencies of the interfering beams (Figure 4c and associated caption disclose tone pairs producing nonredundant beats);
extracting at least one of an amplitude and a phase of each beat oscillation of the time- varying signal (H61, Column 2, Section D discloses finding the complex Fourier spectrum of the signal then removing the phase of the carrier signal, which would leave amplitudes and phases correspond to beat oscillations”), the at least one of the amplitude and phase corresponding to a Fourier component of a spatial Fourier representation of the scene (These are used to reproduce 2D or 3D images of the target, as shown in Figure 3 and Figure 9); and
producing a range-resolved image of the scene by applying a complex-valued weight to each of the Fourier components and applying a Fourier synthesis method to the weighted Fourier components (H50, Column 2, Section B: “Hence, in analogy to projection tomography, the goal is to synthesize a 2D or 3D image from a series of 1D projections. This can be accomplished using direct Fourier synthesis methods”), the range-resolved image having a transverse resolution substantially determined by a maximum spatial separation between any two emitters in the emitter array (This is a well-known property of interferometry and synthetic apertures), and a depth resolution that is substantially equal to c/2B and consequently substantially independent of the maximum spatial separation (This property is inherent to synthetic apertures operated in the mode described here).
FW1 does not teach and Zhang does teach the beam being produced by a respective emitter of an emitter array (Figure 1; Page 2: “As shown in Fig. 1(a), the SOPA beam steers slowly along the x-axis by radiating out of a waveguide-integrated weak grating and quickly along the y-axis by accumulating the (wavelength dependent) propagation phase delay” These indicate one beam emitted from a single SOPA element, which can further be tiled into an array (Page 2, Para 2).).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate the teaching of Zhang to have each beam correspond to a respective emitter into the device of FW1. It is well-known in the LiDAR arts to generate beam arrays with arrays of emitters, as in the SOPA array of Zhang, and a skilled worker would be able to generate multiple beams with this approach with a reasonable expectation of success.
Claims 20, 21, 23, and 24 are rejected under 35 U.S.C. 103 as being unpatentable over Wagner, et al. (Super-Resolved Interferometric Imaging with a Self-Cohering Si-Photonic Beam-Steering LIDAR Array) in view of Zhang and in view of FW1.
Regarding Claim 20, Wagner discloses a range-resolved imager comprising (Page 1: “enabling detection of the LIDAR return signal with the same tile architecture”):
an emitter array that illuminates a scene with a plurality of mutually coherent beams (Page 2, Para 2: “To compensate for these N +M unknown phase offset errors from tile to tile, the array of emitting tiles can be cohered using a self-calibration algorithm,”),
a detector that detects a backscattered signal scattered by an object in the scene and propagating toward the detector (Figure 1: “receive tile”; Page 2: “The moving fringes will produce a back-scattered blinking speckle pattern that is detected by the tiles of the LIDAR receive array,”);
Wagner suggests and Zhang does teach wherein each beam produced by a respective emitter of the emitter array (Figure 1; Page 2: “As shown in Fig. 1(a), the SOPA beam steers slowly along the x-axis by radiating out of a waveguide-integrated weak grating and quickly along the y-axis by accumulating the (wavelength dependent) propagation phase delay” These indicate one beam emitted from a single SOPA element, which can further be tiled into an array (Page 2, Para 2).);
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate an emitter array which only emits one beam per array element into the device of Wagner. It is well-known in the LiDAR arts that the individual elements of an emitter array emit a single beam. Here the examiner assumes that the single beam may also be accompanied by one or more low power lobes. Thus a worker skilled in the art would be able to incorporate an individual emitter emitting an individual beam into a larger array with a reasonable expectation of success.
Wagner does not teach and FW1 does teach a processor (Figure 2a shows a computer and electronics with to a detector and peripherals, and inputs from the detector; the computer contains a processor handling the inputs and outputs); and
a memory storing machine-readable instructions that when executed by the processor, control the processor to execute the method of claim 1 (Figure 2a, the computer contains memory and instructions for executing control programs; H61, Column 1, discloses computer control of signal generation).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate a computer and memory into the LiDAR device of Wagner. Computer control of LiDAR systems and processing of retrieved data are well-known in the art, and a skilled worker would find the incorporation of a computer system to have predictable results.
Regarding Claim 21, which depends from rejected Claim 20, Wagner further discloses the emitter array forming a substantially spatially non-redundant array, each pair of emitters of the non-redundant array being separated by a respective distance that differs from a respective distance between each other pair of emitters of the non- redundant array (Page 2 Paragraph 2: “broadcasting slightly shifted laser frequencies from a non-redundant sub-array of transmit tiles”, Wagner makes it clear here that the non-redundant sub-array is a spatial one since it is explicitly a sub-array of transmit tiles and not of frequencies as is stated in FW1).
Regarding Claim 23, which depends from rejected Claim 20, Wagner further discloses the emitter array including a plurality of emitters, each being one of: a tile of serpentine optical phased array (SOPA) 2D wavelength beamsteering tiles with grating couplers on successive rows (Page 1, Para 1: “This system utilizes high fill-factor serpentine-grating folded-wavelength 2-D beam-steering tiles that can scan multiple optical beams in arbitrary directions from a 2-D planar Silicon-photonic integrated circuit (Si-PIC) emitting aperture.”).
Regarding Claim 24, which depends from rejected Claim 20, Wagner further discloses an array of current summed (Page 1, Para 1: “Current summing of these signals from each mm-sized tile in a large 2-D array of Si-PIC tiles effectively mitigates speckle loss of the return.) serpentine optical phased array (SOPA) receiver tiles incorporating wideband waveguide detectors in each tile (Page 1 Para 1: “By reciprocity, backscattered returns from the illuminated targets are at the exact angle necessary to efficiently couple back into the waveguide and coherently accumulate in the serpentine grating, enabling detection of the LIDAR return signal with the same tile architecture.”)
Claim 26 is rejected under 35 U.S.C. 103 as being unpatentable over Wagner in view of Emadi (US 2020/0041628 A1) and further in view of Campbell (US 2017/0038464 A1).
Regarding Claim 26, Wagner discloses a range-resolved imaging method (Wagner discloses a LiDAR system which can be operated to retrieve a range) comprising:
illuminating a scene with a plurality of substantially overlapping mutually-tilted (Figure 3, “Moving fringes of various orientations are projected onto the illuminated target.”), mutually coherent beams (Page 2: “To compensate for these N +M unknown phase oset errors from tile to tile, the array of emitting tiles can be cohered using a self-calibration algorithm”, thus the beam arrays are mutually coherent after calibration) each having a bandwidth B (Wagner discloses bandwidths of the light engine) and propagating at a speed c (Wagner discloses a ‘light engine’ which emits light propagating at a speed c),
produced by an emitter array with substantially non-redundant spacing (Page 2 Paragraph 2: “broadcasting slightly shifted laser frequencies from a non-redundant sub-array of transmit tiles”, Wagner makes it clear here that the non-redundant sub-array is a spatial one since it is explicitly a sub-array of transmit tiles and not of frequencies as is stated in FW1), said scene being located at a distance substantially greater than c/B from the emitter array (Figure 1 shows several tanks being illuminated by light spanning at least 60 nm of wavelength. Given a median scan wavelength of about 1580 nm, this translates to the distance being much greater than c/B);
causing the plurality of beams to interfere pair-wise such that each pair of mutually- tilted beams produces a spatial fringe pattern (Page 2, Para 2: “produce moving interference fringes through pairwise interference (as shown in the experimental interference fringes in Fig. 4)”);
detecting a time-varying signal backscattered by the scene in response to illumination by the plurality of mutually coherent beams (Page 1, Para 1: “By reciprocity, backscattered returns from the illuminated targets are at the exact angle necessary to efficiently couple back into the waveguide and coherently accumulate in the serpentine grating, enabling detection of the LIDAR return signal with the same tile architecture.”);
processing the time-varying signal, the amplitudes and phases corresponding to selected spatial Fourier components of the scene (Page 2, Para 2: “that measure individual Fourier components of the reflectivity profile, as illustrated in Fig. 3 and 5. This allows the formation of a high-resolution sub-image within each wavelength-steered beam by Fourier synthesis.”; Page 2, Para 2: “The moving fringes will produce a back-scattered blinking speckle pattern that is detected by the tiles of the LIDAR receive array, encoding the complex spatial Fourier components of the object on the amplitude and phase of the corresponding temporal frequencies,”);
producing a range-resolved image of the scene by applying a complex-valued weight to each of the selected Fourier components and applying a Fourier synthesis method to the weighted Fourier components (Page 2, Para 3: “This paper presents the design, analysis, and initial experimental demonstration of 2-D wavelength beam steering, vernier grating-lobe suppression, interferometric Fourier synthesis of object spatial reflectivity using the SCALABLE Si-PIC devices, and its potential application in LIDAR remote sensing.”), the range-resolved image having a transverse resolution substantially determined by a maximum spatial separation between any two of a plurality of emitters, of the emitter array, and a depth resolution that is substantially equal to c/2B and consequently substantially independent of the maximum spatial separation (These resolutions are inherent to the system described, and are well-known properties of synthetic apertures),.
Wagner does not teach and Emadi does teach wherein the beams are encoded with unique PN coded intensity modulation (Figures 8A and 8B; [0047]: “Next, in an operation 106, a sinusoidal (e.g. cosine) wave is modulated by the binary code to form a series of bits (“chips”) on a sinusoidal carrier wave.”).
and wherein the processing of the time-varying signal further comprises using a circulant correlation with a reference bipolar PN code to produce correlation peaks corresponding to each unique PN modulation ([0047]: “FIG. 7 is a flow diagram of a method 102, set forth by way of example and not limitation, for distinguishing a phase-shifted reflected waveform of a transmitted waveform from other waveforms. In an operation 104, a binary code with impulse-like cyclic autocorrelation properties is obtained, e.g. from MLS generator 96, from a look-up table, etc…. Next, in an operation 110, a reflected waveform is received, e.g. by a photodetector, and is demodulated in an operation 112 using the same binary code that was used to create the transmitted waveform.”; and to extract an amplitude and phase for each correlation peak ([0044]-[0048], the cyclic autocorrelation function is the amplitude of the Fourier component).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the 3D imaging method of Wagner with the encoding of Emadi’s time of flight sensing method using the cyclic autocorrelation function. Emadi notes that maximal length pseudorandom binary codes can be used to disambiguate LiDAR signals, which is useful to reject interferences from the same or other LiDAR devices and promotes safety.
Wagner in view of Emadi does not teach and Campbell does teach wherein the LiDAR output is Binary- Phase-Shift-Keyed (BPSK) maximal-length pseudo-noise (PN) encoded ([0004]: “The various embodiments enable closely spaced carriers to be modulated with the same periodic PN sequence using BPSK modulation.”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate the teaching of Campbell to use BPSK into the method of Wagner in view of Emadi. Campbell notes in [0004] that “In this manner, even though the carriers may almost entirely share bandwidth, orthogonality of the carriers may not be lost” and that “by using orthogonal carriers the various embodiments enable measurements to be made simultaneously, thereby reducing the error compared to systems that require sequential measurements, such as pulsed Lidar systems.”
Claim 27 is rejected under 35 U.S.C. 103 as being unpatentable over Wagner in view of Emadi (US 2020/0041628 A1) and further in view of Campbell (US 2017/0038464 A1) and further in view of Saxena (US 2021/0279055 A1).
Regarding Claim 27, which depends from rejected Claim 26, Emadi further teaches an interferometric product of +1 and -1 symbols ([0048]: “The chips C can have a value of +1 or −1. That is, for each positive chip there is a positive burst of cosine waves, and for each negative chip there is a negative burst of cosine waves.”) and the shift-add property ([0031]: “CORDIC algorithms belong to the class of shift-and-add algorithms”, the algorithm described here is a phase estimator implemented with Volder’s algorithm).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate these teachings of Emadi into the existing method of Wagner in view of Emadi and further in view of Campbell. Emadi notes that maximal length pseudorandom binary codes, which can be implemented with the shift-and-add property and +1 and -1 symbols, can be used to disambiguate LiDAR signals ([0046]), which is useful to reject interferences from the same or other LiDAR devices and improves safety.
Wagner, Emadi, and Campbell do not teach and Saxena does teach wherein the operations are performed over a Galois field and implemented with a logical XOR ([0070]: “determining a transformation result at block 106 includes determining a Galois residue value in response to performing a BMMA operation. In at least one embodiment, determining Galois residue value includes calculating Galois residue value in response to performing BMMA operation. In at least one embodiment, one or more circuits of a processor determine Galois residue value based, at least in part, on an XOR operation applied to at least a portion of a result of a bitwise AND operation”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to implement the teachings of Wagner, Emadi, and Campbell using the teachings of Saxena to do so over a Galois field and for them to be implemented with a logical XOR. These mathematical objects and operations could be implemented by a skilled worker with a reasonable expectation of success.
Claim 28 is rejected under 35 U.S.C. 103 as being unpatentable over Wagner in view of Emadi (US 2020/0041628 A1) and further in view of Campbell (US 2017/0038464 A1) and further in view of Ferreira (US 2020/0284883 A1).
Regarding Claim 28, which depends from rejected Claim 26, Emadi further teaches an interferometric product of +1 and -1 symbols ([0048]: “The chips C can have a value of +1 or −1. That is, for each positive chip there is a positive burst of cosine waves, and for each negative chip there is a negative burst of cosine waves.”)
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate these teachings of Emadi into the existing method of Wagner in view of Emadi and further in view of Campbell. Emadi notes that maximal length pseudorandom binary codes, which can be implemented with +1 and -1 symbols, can be used to disambiguate LiDAR signals ([0046]), which is useful to reject interferences from the same or other LiDAR devices and improves safety.
Wagner, Emadi, and Campbell do not teach and Ferreira does teach wherein the unique PN coded intensity modulation comprises a unique Gold-code sequence produced by implementing a logical XOR operation ([4609]: “the term “signal modulation” (also referred to as “electrical modulation”) may be used to describe a modulation of a signal for encoding data in such signal (e.g., a light signal or an electrical signal, for example a LIDAR signal).”; [4648]:” The encoding process may include (or use) one or more signal modulation codes (e.g., spreading codes) for encoding (e.g., electrically modulating) the frame, such as Walsh codes, Hadamard matrices, Gold code construction schemes, and PN sequences. The encoding process may include a XOR operation between a code (e.g., a signal modulation code) and one or more symbols of a frame (e.g., a sequence of symbols, for example a binary symbol sequence). The XOR operation may provide an encoded representation of the one or more input symbols (e.g., a CDMA-encoded representation of the input sequence).”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to implement the teachings of Wagner, Emadi, and Campbell using the teachings of Ferreira to do so with Gold codes and for them to be implemented with a logical XOR. These mathematical objects and operations could be implemented by a skilled worker with a reasonable expectation of success.
Claims 3 and 30 are rejected under 35 U.S.C. 103 as being unpatentable over FW1 in view of Zhang as applied to claim 1 above, and further in view of Asundi (US 2009/0091811 A1).
Regarding Claim 3, FW1 further teaches the emitter array including a first emitter and a second emitter displaced from the first emitter by Δx in a first direction and Δy in a second direction perpendicular thereto, and further comprising:
Generating a first beam of the plurality of mutually coherent beams having a first carrier frequency (c/λ + f1), where λ is a reference wavelength (Figure 2, ω is the reference frequency and Ω1 and Ω2 are distinct shifts; H51 Column 2 describes shifting the base frequency by the carrier frequency generated);
generating a second beam of the plurality of mutually coherent beams having a second carrier frequency (c/λ + f2) (Figure 2, ω is the reference frequency and Ω1 and Ω2 are distinct shifts; H51 Column 2 describes shifting the base frequency by the carrier frequency generated);
interfering the first beam and the second beam at a far-field distance z0 from the emitter array (FW1 discloses a working distance of 20 cm and suggests a depth resolution on the order of tens of microns, rendering the scene in the far field), where the first beam and the second beam overlap to produce a traveling sinusoidal intensity-fringe pattern with longitudinal fringe spacing c/(f1-f2) (this fringe spacing is mathematically inherent to the choice of frequencies) incident onto the scene (Figure 2 shows the overlap of beams on the object in the left panel. The right panel shows the traveling fringe intensity at the object; Figure 4c and 4d shows the plurality of beat frequencies generated by the overlap; H50 Column 2: “However, it is also possible to drive the Bragg cell with many tone pairs simultaneously, producing multiple acoustic beats and creating a superposition of running fringe patterns with different spatial frequencies at the object.”), the longitudinal fringe spacing being independent of a propagation angle between the first beam and the second beam (Given that the beams of FW1 are largely overlapping and pointing in the same direction, it is reasonable to assume here that a small angle approximation applies, and that the fringe spacing is therefore essentially independent of a propagation angle of the beams);
the selected Fourier components including 3-D Fourier components (u, v, w) of the scene having transverse components u =Δx/λz0,v=Δy/λz0, and a longitudinal component w 2(f1-f2)/c, at least one of Δx and Δy being non-zero (these are the mathematical results one skilled in the art would expect from an array of two emitters displaced from each other and emitting at slightly different wavelengths).
FW1 does not teach and Asundi does teach wherein the beam is expanding at the scene ([0050]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate the teaching of Asundi to have a diverging beam at the object into the device of FW1in view of Zhang. Asundi notes in [0004] that a diverging beam illumination source “may have the advantage that the hardware configuration is simplified and/or reduced in size by removing the need for lenses.” Simplified hardware configurations result in fewer parts which may fail and lower costs.
Asundi does not explicitly teach two illuminations beams but it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to duplicate the teaching of Asundi in a system in which two or more beams are used, and would achieve a predictable result. It has been held that mere duplication of parts has no patentable significance unless a new and unexpected result is produced. The examiner refers applicant to MPEP 2144.04(VI)(B) and In re Harza, 274 F.2d 669, 124 USPQ 378 (CCPA 1960).
Regarding Claim 30, which depends from rejected Claim 3, FW1 further discloses the traveling sinusoidal fringe pattern being traveling at a wave group velocity Δω/Δk, where Δω and Δk are, respectively, the difference in angular frequency and wave vector of the first beam and the second beam (This is a well-known relationship describing the wave group velocity of two interfering plane waves with different frequencies and different wave vectors.).
Claims 8 and 31 are rejected under 35 U.S.C. 103 as being unpatentable over FW1 in view of Zhang and in view of Wagner
Regarding Claim 8, FW1 in view of Zhang discloses all the limitations of Claim 1 as analyzed above. FW1 does not teach and Zhang does not teach and Wagner does teach calibrating at least one of the amplitudes and phases of the plurality of mutually coherent beams using a complex coefficient retrieval method (Page 2: “The moving fringes will produce a back-scattered blinking speckle pattern that is detected by the tiles of the LIDAR receive array, encoding the complex spatial Fourier components of the object on the amplitude and phase of the corresponding temporal frequencies, plus a tile phase calibration error φjk’ -φj’k. To compensate for these N +M unknown phase offset errors from tile to tile, the array of emitting tiles can be cohered using a self-calibration algorithm.” Wagner references the self-calibration algorithm of Schwab, which is known to be implemented iteratively.).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the 3D imaging method of FW1 with the calibration method of Wagner. Wagner notes that this calibration procedure allows for achieving the full resolution capabilities of the array of wavelength controlled 2-D beam-steering tiles.
Regarding Claim 31, which depends from rejected Claim 1, FW1 suggests simultaneously illuminating the scene with multiple mutually coherent beams, but does not explicitly teach simultaneously illuminating the scene the all of the plurality of mutually coherent beams (For example, by coherently combining twenty 2MHz wide FM measurements, …).
Wagner teaches illuminating comprising simultaneously illuminating the scene with the plurality of mutually coherent beams, the collective bandwidth B being the bandwidth of the plurality of mutually coherent beams (A T-shaped sub-array topology for SCALABLE is shown in the simulation in Fig. 5 in which the kth element in the j0th row of N transmit apertures of pitch d is frequency shifted by k_f with small interelement increment (say _f = :1MHz spanning 10MHz across N = 100 tiles horizontally), while the jth element in the k’th column is frequency shifted by j_f with a large increment (say _f = N_f = 10MHz spanning 1GHz across N = 100 tiles vertically).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate the teaching of Wagner to simultaneously illuminate the target scene with all the mutually coherent beams into the device of FW1 in view of Zhang. Wagner notes that this allows for the formation of high-resolution images, which can provide the end user with better detection capabilities.
Claims 25 is rejected under 35 U.S.C. 103 as being unpatentable over FW1 in view of Zhang and in view of Wagner and further in view of Donovan (US 2017/0307736 A1).
Regarding Claim 25, which depends from rejected Claim 1, Wagner further teaches the emitter array being a two-dimensional emitter array including a plurality of emitters, at least four in number, each having a respective location projected onto a plane (Page 1, Para 1: “These Si-PIC beam-steering tiles can be close packed into a large 2-D array, as shown in Fig. 4,”; Figure 1 shows an array of emitters as well), which emits a plurality of mutually coherent beams (To compensate for these N +M unknown phase offset errors from tile to tile, the array of emitting tiles can be cohered using a self-calibration algorithm, thereby achieving the full resolution capabilities of the array of wavelength controlled 2-D beam-steering tiles).;
Wagner does not teach and Donovan does teach each beam of the plurality of beams having a respective one of a plurality of frequencies that, when plotted as a height above the plane and aligned to the respective locations of the emitters, form a non-planar array of frequencies ([0042]: “FIG. 3 illustrates a multi-element emitter laser source 300 with two different VCSEL wavelengths interleaved uniformly in the vertical direction.” These frequencies, when plotted as a function of 2D position, would not form a plane.).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate the teaching of Donovan to have multiple lasers at multiple wavelengths spatially arranged as described in the limitation above. Donovan notes in [0031] that “one feature of LIDAR systems of some embodiments of the present teaching is that they use multiple laser wavelengths to enable finer angular resolution and performance in a low-cost, compact optical design.” Donovan further notes in [0081] and [0082] that transmitter array with overlap at the target range have improved angular resolutions, and that the arrays can be arranged on a single substrate, which can help promote overlap at the target range.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Morarity (US 2020/0300983) discloses a light detection and ranging system which modulates laser pulses with a frequency shift keyed encoding. The disclosed device emits light at a plurality of simultaneous wavelengths.
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/B.W.C./Examiner, Art Unit 3645
/ISAM A ALSOMIRI/Supervisory Patent Examiner, Art Unit 3645
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