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 .
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 05/26/2023 was considered by the examiner.
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 and 3-6 are rejected under 35 U.S.C. 103 as being unpatentable over Roth (US 2020/0256669 A1) in view of Smits (US 2017/0176575 A1).
Regarding Claim 1, Roth discloses a system for time-of-flight distance measurement ([0002]), comprising:
an emitter (Figure 2B; [0008]: “ In some embodiments, the radiation source includes at least one vertical-cavity surface-emitting laser (VCSEL), and may include an array of VCSELs.”), configured to project pulsed beams to a target region that are reflected by the target region to form light spots ([0007]: “There is therefore provided, in accordance with an embodiment of the invention, depth sensing apparatus, including a radiation source, which is configured to emit a first plurality of beams of light pulses toward a target scene.”);
a collector, comprising a pixel unit comprising a plurality of pixels, and configured to receive the light spots ([0008]: “Additionally or alternatively, the sensing elements include single-photon avalanche diodes (SPADs).”; [0005]: “Each sensing element outputs a signal indicative of a time of incidence of a single photon on the sensing element. (Each sensing element in such an array is also referred to as a “pixel.””)). ;
and a processing circuit ([0007]: “Processing and control circuitry is coupled to receive the signals from the array”), synchronizing trigger signals of the emitter and the collector ([0005]: “Circuitry is coupled to actuate the sensing elements only in a selected region of the array and to sweep the selected region over the array in synchronization with scanning of the at least one beam.), and processing photonic signals in the light spots ([0007]: “and to process the signals from the identified regions in order determine respective times of arrival of the light pulses.”), to calculate distance information of a target in the target region ([0046]: “As further described below in reference to FIG. 4, processing units 28 together with combining unit 35 may assemble histograms of the times of arrival of multiple pulses emitted by array 22, and thus output signals that are indicative of the distance to respective points in scene 32, as well as of signal strength.”), wherein the collector further comprises a memory and a first processing circuit ([0007]: “and to process the signals from the identified regions in order determine respective times of arrival of the light pulses.”);
the memory is configured to store serial numbers of the light spots during system calibration, ([0028]: “Alternatively or additionally, a small subset of the locations of laser spots can be identified in an initialization stage. These locations can be used in subsequent iterative stages to predict and verify the positions of further laser spots until a sufficient number of laser spots have been located.” Given that the spot locations are stored and subsequently used in later steps, they must reside in memory and be uniquely labeled to provide consist calculations across iterative steps.) and spatial emission angle factors of the light spots with different serial numbers; and the first processing circuit is configured to calculate coordinates of offset light spots after impact deformation occurs in the system, and obtain serial numbers of the offset light spots ([0065]: “At some later stage, however, spots 72 shifted to new locations 72b on array 24. This shift may have occurred, for example, due to mechanical shock or thermal effects in imaging device 22, or due to other causes. Spots 72 at locations 72b no longer overlap with super-pixels 80 in area 76, or overlap only minimally with the super-pixels. Sensing elements 78 on which the spots are now imaged, however, are inactive and are not connected to any of processing units 28. To rectify this situation, controller 26 may recalibrate the locations of super-pixels 80, as described in the above-mentioned provisional patent applications.”);
and the processing circuit calibrates the system after the impact deformation occurs, according to the coordinates of the offset light spots and the serial numbers of the offset light spots ([0065]), to obtain new spatial emission angle factors.
Roth suggests but does not explicitly teach ([0040]: “ the positions of further laser spots are predicted by a model and verified.” The angle factors would be necessary to predict the positions.) and Smits does teach that the device obtains spatial emission angle factors ([0125]: “In one or more of the various embodiments, the transmit system 404 may determine (e.g., ex ante) a pointing direction of the scanning beam 406 in two dimensions.”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device of Roth with the teaching of Smits to obtain spatial emission factors of the system. Calculating spatial emission factors, that is, an indicator of a ray’s direction of travel, is well-known in the art, and a skilled worker would find both obtaining and using these well-established quantities to yield predictable results.
Regarding Claim 3, which depends from rejected Claim 1, Roth further discloses wherein the processing circuit is configured to turn on a portion of light sources of the emitter ([0028]: “ For this purpose, processing and control circuitry receives timing signals from the array and searches over the sensing elements in order to identify the respective regions of the array on which the light pulses reflected from the target scene are incident.” A portion of the emitters must be activated to perform this procedure.), and determine positions of offset light spots on the pixel unit ([0028]: “some embodiments of the present invention provide methods for calibrating the locations of the laser spots on the SPAD array.”; [0078], [0079]), and the first processing circuit is configured to obtain serial numbers of the offset light spots on the pixel unit according to a correspondence between the serial numbers of the light spots and the light sources ([0028]: “Alternatively or additionally, a small subset of the locations of laser spots can be identified in an initialization stage. These locations can be used in subsequent iterative stages to predict and verify the positions of further laser spots until a sufficient number of laser spots have been located.” Given that the spot locations are stored and subsequently used in later steps, they must reside in memory and be uniquely labeled to provide consist calculations across iterative steps.).
Regarding Claim 4, which depends from rejected Claim 3, Roth further discloses wherein the processing circuit comprises a second processing circuit, configured to control a bias voltage of pixels corresponding to the positions of the offset light spots on the pixel unit, activate the pixels to collect photons in the offset light spots on the pixel unit ([0026]: “ At any instant during operation of the system, only the sensing elements in the area or areas of the array that are to receive reflected illumination from a beam are actuated, for example by appropriate biasing of the SPADs in selected super-pixels, while the remaining sensing elements are inactive.”), and to output a photon detection signal ([0013]: “The target scene is imaged onto an array of a second plurality of sensing elements, configured to output signals indicative of respective times of incidence of photons on the sensing element”).
Regarding Claim 5, which depends from rejected Claim 3, Roth further discloses wherein the light sources comprise a VCSEL array light source ([0057]: “FIG. 2A is a schematic side view of radiation source 21, in accordance with an embodiment of the invention. VCSEL array 22 comprises an integrated circuit chip on which multiple banks of VCSELs are formed (as shown in FIG. 2B, for example)”.)
Regarding Claim 6, Roth discloses a method for search of light spot positions ([0028]: “In response to this problem, some embodiments of the present invention provide methods for calibrating the locations of the laser spots on the SPAD array.”), comprising:
calibrating spatial template distribution ([0064]: “In this example, it is assumed that during an initial calibration stage, spots 72 were imaged onto array 24 at locations 72a.” Thus there is some initial distribution of spots which are calibrated.) of light spots in an object space of a distance measurement system ([0046]: “and thus output signals that are indicative of the distance to respective points in scene 32, as well as of signal strength.”) and spatial emission angle factors of the light spots;
calculating coordinates of offset light spots on a pixel unit of a collector after impact deformation occurs in the distance measurement system ([0027]: “the locations of the reflected beams on the detector array can change, for example due to thermal and mechanical changes over time, as well as optical effects, such as parallax.” [0035]: “However, temperature changes during operation, as well as mechanical shocks, may alter the mechanical parameters of the mapping, thus modifying the positions of the laser spots on the SPAD array and necessitating recalibration during operation in the field.”), and obtaining serial numbers of the offset light spots ([0028]: “Alternatively or additionally, a small subset of the locations of laser spots can be identified in an initialization stage. These locations can be used in subsequent iterative stages to predict and verify the positions of further laser spots until a sufficient number of laser spots have been located.” Given that the spot locations are stored and subsequently used in later steps, they must reside in memory and be uniquely labeled to provide consistent calculations across iterative steps.);
and according to the coordinates of the offset light spots on the pixel unit of the collector and the serial numbers, calibrating the distance measurement system after the impact deformation occurs ([0028]: “In response to this problem, some embodiments of the present invention provide methods for calibrating the locations of the laser spots on the SPAD array.”) to obtain new spatial emission angle factors, and completing the search of light spot positions.
Roth suggests but does not explicitly teach ([0040]: “ the positions of further laser spots are predicted by a model and verified.” The angle factors would be necessary to predict the positions.) and Smits does teach that the device obtains spatial emission angle factors ([0125]: “In one or more of the various embodiments, the transmit system 404 may determine (e.g., ex ante) a pointing direction of the scanning beam 406 in two dimensions.”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device of Roth with the teaching of Smits to obtain spatial emission factors of the system. Calculating spatial emission factors, that is, an indicator of a ray’s direction of travel, is well-known in the art, and a skilled worker would find both obtaining and using these well-established quantities to yield predictable results.
Claim 7, 9, and 10 are rejected under 35 U.S.C. 103 as being unpatentable over Roth in view of Smits and in view of Shirley (WO 02/086420 A1).
Regarding Claim 7, which depends from rejected Claim 6, Roth further discloses wherein the calibrating the spatial template distribution of the light spots ([0064]: “In this example, it is assumed that during an initial calibration stage, spots 72 were imaged onto array 24 at locations 72a.” Thus there is some initial distribution of spots which are calibrated.) comprises controlling an emitter to project pulsed beams onto the target ([0007]: “There is therefore provided, in accordance with an embodiment of the invention, depth sensing apparatus, including a radiation source, which is configured to emit a first plurality of beams of light pulses toward a target scene.”) that are reflected by the target to form the light spots ([0007]: “ Light collection optics are configured to image the target scene onto the array of sensing elements.), and the method further comprises identifying and numbering the light spots, and calculating the spatial emission angle factors of the light spots with different serial numbers and the spatial template distribution of the light spots in the object space.
Roth in view of Smits does not teach and Shirley does teach placing a calibration plate in front of the distance measurement system and photographing the target using a camera ([0044]: “The camera will record the reflected spots which correspond to the imaging systems measurement of where the calibration target 100 is located.” Note that the camera 440 is distinct from the fringe interference detectors 420.),
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Roth in view of Smits with the teaching of Shirley to image the calibration plate with a camera. Shirley notes that “the camera will record the reflected spots which correspond to the imaging systems measurement of where the calibration target 100 is located. The centroids of the reflected spots may be determined through one of many algorithms known to one of ordinary skill in the art.” Thus, the use of a camera here allows for better estimation of spot centers, and therefore a more robust and reliable calibration.
Regarding Claim 9, which depends from rejected Claim 7, Roth further discloses wherein the calculating the coordinates of the offset light spots comprises: turning on a portion of light sources of the emitter ([0028]: “ For this purpose, processing and control circuitry receives timing signals from the array and searches over the sensing elements in order to identify the respective regions of the array on which the light pulses reflected from the target scene are incident.” A portion of the emitters must be activated to perform this procedure.), determining coordinates of the offset light spots on the pixel unit ([0028]: “some embodiments of the present invention provide methods for calibrating the locations of the laser spots on the SPAD array.”), obtaining the serial numbers of the offset light spots according to a correspondence between the serial numbers of the light spots and the light sources ([0028]: “Alternatively or additionally, a small subset of the locations of laser spots can be identified in an initialization stage. These locations can be used in subsequent iterative stages to predict and verify the positions of further laser spots until a sufficient number of laser spots have been located.” Given that the spot locations are stored and subsequently used in later steps, they must reside in memory and be uniquely labeled to provide consist calculations across iterative steps.).
Regarding Claim 10, Roth discloses a method for distance measurement ([0002]), comprising:
controlling an emitter (Figure 2B; [0008]: “ In some embodiments, the radiation source includes at least one vertical-cavity surface-emitting laser (VCSEL), and may include an array of VCSELs.”) to emit pulsed beams towards a target region ([0007]: “There is therefore provided, in accordance with an embodiment of the invention, depth sensing apparatus, including a radiation source, which is configured to emit a first plurality of beams of light pulses toward a target scene.”), and a portion of the pulsed beams is reflected and incident on a sensing region in a collector to form light spots ([0028]: “ Detailed knowledge of the depth mapping system may be used in order to pre-compute likely regions of the reflected laser spots to be imaged onto the SPAD array.”), wherein the sensing region comprises at least one pixel unit, and the pixel unit comprises a plurality of pixels ([0026]: “SPADs are grouped together into “super-pixels,” wherein the term “super-pixel” refers to a group of mutually-adjacent pixels along with data processing elements that are coupled directly to these pixels.);
controlling the sensing region in the collector to collect photons in the light spots ([0026]: “At any instant during operation of the system, only the sensing elements in the area or areas of the array that are to receive reflected illumination from a beam are actuated, for example by appropriate biasing of the SPADs in selected super-pixels, while the remaining sensing elements are inactive.) and output a photon detection signal ([0067]: “Each processing unit 28 comprises one or more time-to-digital converters (TDC) 143, wherein the TDCs are hardware elements translating the avalanche events (signals from a SPAD pixel due to a detected photon) from each sensing element 78 to time-of-arrival information”), wherein the sensing region is a pre-calibrated initial sensing region ([0035]: A mapping of SPAD pixels to processing units, i.e., the assignment of SPAD pixels to super-pixels, may be determined initially during a factory calibration.);
determining whether a center position of the light spots is the same as a position of the pre- calibrated initial sensing region, ([0064]: “ In this example, it is assumed that during an initial calibration stage, spots 72 were imaged onto array 24 at locations 72a.”) and if determining that the center position of the light spots is not the same as the position of the initial sensing region ([0065]: “At some later stage, however, spots 72 shifted to new locations 72b on array 24. This shift may have occurred, for example, due to mechanical shock or thermal effects in imaging device 22, or due to other causes.”), determining a position of a second sensing region corresponding to the light spots through the method according to claim 6, and activating the second sensing region to collect the photons in the light spots to output the photon detection signal ([0078]: “Once the search regions have been chosen in pre-computation step 156, controller 26, in a random iterative search step 158, fires a succession of pulses of beams 32 from VCSEL array 22 (FIG. 1), and at the same time performs random searches within the search regions to identify the M super-pixels that receive the pulsed beams.; [0079]: “Once controller 26 has found the M super-pixels, it finishes the search and assigns, in an assignment step 160, these super-pixels for use in 3D mapping of scene 32 by depth mapping system 20.”) ;
and receiving the photon detection signal to form a photon detection event signal ([0067]: “Each processing unit 28 comprises one or more time-to-digital converters (TDC) 143, wherein the TDCs are hardware elements translating the avalanche events (signals from a SPAD pixel due to a detected photon) from each sensing element 78 to time-of-arrival information), forming a histogram based on the photon detection event signal, ([0067]: “Each processing unit 28 further comprises, for each TDC 143, a weight 144, and may comprise a histogram unit (not shown), wherein the time-of-arrival information is aggregated into histograms, generally over thousands of pulses from VCSEL array 22.”) and calculating distance information according to the histogram ([0069]: “This combined histogram 146 is sent to DPU 27, which in turn detects, based on histogram 146, whether any object or structure was detected in scene 32 by super-pixel 80 and, if so, reports its depth information based on time-of-flight data.”).
Roth in view of Smits does not teach and Shirley does teach wherein the position of the light spot is its center position ([0043]: “The centroids of the reflected spots may be determined through one of many algorithms known to one of ordinary skill in the art.).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Roth in view of Smits with the teaching of Shirley to characterize the position of the light spot with a center position. Shirley notes in [0046] that the centroiding procedure “yields high-precision values of the i,j, and N locations of the centroid of each active spot 210.” Accurate spot locations are a necessary requirement for any calibration procedure, and would result in more robust and trustworthy results.
Allowable Subject Matter
Claims 2 and 8 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. The equations contained in these claims disclose a relationship between light spots before and after a deformation occurs in a time-of-flight distance measurement system. Roth ([0084]-[0086]) discloses homographic transformations which are superficially similar, but with a different form that does not include third-order terms, for example. Cao (US 2023/0342883 A1) discloses that such transformations ([0080]) “may be in homography, or may be a complex large deformation model,” but does not specify a form for such a model.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to BENJAMIN WADE CLOUSER whose telephone number is (571)272-0378. The examiner can normally be reached M-F 7:30 - 5:00.
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/B.W.C./Examiner, Art Unit 3645
/ISAM A ALSOMIRI/Supervisory Patent Examiner, Art Unit 3645