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 .
Priority
Acknowledgment is made of applicant’s claim for foreign priority under 35 U.S.C. 119 (a)-(d). The certified copy has been filed in parent Application No. EP24159564.4, filed on 02/26/2024.
Drawings
The drawings are objected to because Fig. 2. Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. The figure or figure number of an amended drawing should not be labeled as “amended.” If a drawing figure is to be canceled, the appropriate figure must be removed from the replacement sheet, and where necessary, the remaining figures must be renumbered and appropriate changes made to the brief description of the several views of the drawings for consistency. Additional replacement sheets may be necessary to show the renumbering of the remaining figures. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
Specification
The disclosure is objected to because of the following informalities:
[0040], the third peak represents the interface between the mixed layer 304 and water 302 omits the reference character for that peak, which [0042] and Fig. 3A identify as 312; the passage should read “the third peak 312.”
[0035], the WirelessHART protocol is identified as IEC 620691. That designation does not appear to correspond to the international standard for the WirelessHART protocol, which is designated IEC 62591. Applicant is required to verify and correct the designation.
The abstract of the disclosure is objected to because the final clause, . A corrected abstract of the disclosure is required and must be presented on a separate sheet, apart from any other text. See MPEP § 608.01(b).
Appropriate correction is required.
Claim Objections
Claim 1 objected to because of the following informalities:
Claim 1 is objected to because the final limitation, determining a location of a material interface based on the location of the second peak, uses a gerund, while each preceding limitation following the control circuitry being further configured to is an infinitive (transmit, receive, detect, determine, apply). The limitation should read “determine a location of a material interface based on the location of the second peak.” The examiner interprets the limitation as a function the control circuitry is configured to perform. Claim 7, as a method claim, correctly uses the gerund and is not affected.
Claim 7 is objected to because it begins Method of determining without an article. The claim should begin “A method of determining.”
Claim 7 is further objected to because the product (in a reflection of the transmit signal at a surface of the product) and the fill level (in control circuitry configured to determine the fill level) lack antecedent basis. Unlike claim 1, the preamble of claim 7 does not introduce a product or a fill level. Because the claim as a whole makes plain that the product is the product contained in the tank and the fill level is the fill level of that product, the scope is reasonably ascertainable and the matter is treated as an objection (MPEP § 2173.05(e)). For purposes of examination, the examiner interprets claim 7 as reciting a tank containing a product and a fill level of that product. Correction is required, for example “a material interface in a tank containing a product” and “control circuitry configured to determine a fill level of the product.” Correction of claim 7 will also supply antecedent basis for the product in the tank in claims 9, 10, 11, and 12.
Claims 1, 2, 7, and 8 are objected to because the signal terminology is introduced more than once and then referenced inconsistently. Claim 1 first recites a transceiver configured to provide a transmit signal, and to receive a reflected signal resulting from a reflection of the transmit signal and then recites transmit a signal along the probe and receive a reflected signal, which introduce a second signal and a second reflected signal. Claim 1 then refers to the received signal (in the detecting step), a term not recited verbatim, and to the signal (in apply a sliding window peak detection algorithm to the signal), whose literal antecedent is the signal transmitted along the probe. Claim 2 refers to an energy content of the signal. Claims 7 and 8 contain the same language (transmitting a signal along the probe, receiving a reflected signal, detecting a first peak in the received signal, applying a sliding window peak detection algorithm to the signal, and determining an energy content of the signal). Read as a whole and considering [0044-0045] and Figs. 4A-4B (signal 400), the identity of each signal is plain, and the matter is treated as an objection. The examiner interprets the signal transmitted along the probe as the transmit signal, the reflected signal received as the reflected signal resulting from reflection of the transmit signal, and the received signal and the signal in claims 1, 2, 7, and 8 as that received reflected signal. Correction is required, for example “transmit the transmit signal along the probe; receive the reflected signal; detect a first peak in the received reflected signal” and “apply a sliding window peak detection algorithm to the received reflected signal,” with conforming changes to claims 2, 7, and 8.
Claims 2 and 8 are objected to because the location of the interface departs from the term a material interface introduced in claims 1 and 7. The examiner interprets the interface as the material interface of the parent claim. The claims should read “the location of the material interface.”
Claims 3, 4, 9, and 10 are objected to because the claims recite echoes while claims 1 and 7 recite peaks. In claims 3 and 9, the first detected echo exceeding the first threshold amplitude lacks literal antecedent basis; the parent claims recite a first peak having a first amplitude exceeding a first threshold amplitude. The specification uses peak and echo interchangeably for the same feature ([0009], [0015], [0044]), so the examiner interprets the first detected echo exceeding the first threshold amplitude as the first peak of claims 1 and 7. In claims 4 and 10, the first detected echo after the surface echo introduces a different echo and should be introduced with “a.” Correction is required, for example “the first peak” in claims 3 and 9 and “a first detected echo after the surface echo” in claims 4 and 10.
Claim 3 is further objected to because (1) represent does not agree with its singular subject and should read “represents,” and (2) a surface of the product reintroduces the surface already recited in claim 1 (a reflection of the transmit signal at a surface of the product) and should read “the surface of the product.”
Claim 4 is further objected to because the surface echo lacks antecedent basis. Claim 3 recites that an echo represents a surface but does not introduce a surface echo, in contrast to claim 9, which defines the echo as a surface echo. The examiner interprets the surface echo as the first detected echo of claim 3. Claim 3 may be amended, for example, to recite that the echo “represents the surface of the product as a surface echo,” or claim 4 may refer to “the first detected echo of claim 3.”
Claim 9 is objected to because representing level of the product omits an article. The claim should read “representing a level of the product.” Because claim 7 does not recite a fill level of the product (see the objection to claim 7 above), applicant may instead conform the term to “the fill level of the product” after claim 7 is corrected.
Claim 14 is objected to because cause the processing circuitry to perform the method of claim 7 refers to processing circuitry, which has no antecedent basis, while the same claim recites when executed by the control circuitry. The claim context and the specification ([0021], [0038]) make plain that a single control circuitry both executes the instructions and performs the method, so the matter is treated as an objection. The examiner interprets the processing circuitry as the control circuitry. The claim should read “cause the control circuitry to perform the method of claim 7.”
Appropriate correction is required.
Claim Rejections - 35 USC § 101
35 U.S.C. 101 reads as follows:
Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title.
Claim 13 rejected under 35 U.S.C. 101 because the claimed invention is directed to non-statutory subject matter. The claim(s) does/do not fall within at least one of the four categories of patent eligible subject matter because:
The claim recites A computer program product comprising program code for performing, when executed by the control circuitry, the method of claim 7. At Step 1 (MPEP § 2106.03), the claim must fall within one of the four statutory categories. The claim recites only program code and does not require that the code be stored on or embodied in any tangible, non-transitory medium. The specification describes the computer program product separately from a non-transitory computer-readable storage medium comprising instructions ([0021]), which indicates that the computer program product is not limited to a non-transitory medium. Under the broadest reasonable interpretation, claim 13 therefore encompasses program code per se and program code carried by a transitory propagating signal. Software per se is not a process, machine, manufacture, or composition of matter (MPEP § 2106.03, subsection I), and a transitory propagating signal is not within any statutory category. Claim 13 is not patent eligible. The rejection may be overcome by amending the claim to recite, for example, “A computer program product comprising a non-transitory computer-readable medium storing program code which, when executed by the control circuitry, performs the method of claim 7.”
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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1, 3, 4, 7, 9, 10, 13, and 14 are rejected under 35 U.S.C. 103 as being unpatentable over Fauveau (US 7,334,451 B1) in view of Weinberg, G. V. (2017). (An Introduction to Radar Sliding Window Detectors. https://doi.org/10.48550/arxiv.1709.09786) (hereinafter “Weinberg”).
Claims 1 and 7, Fauveau (‘451) in view of Weinberg teaches:
Fauveau (‘451) teaches: A guided wave radar level gauge for determining a fill level of a product contained in a tank comprising: (Col 2, lines 42-43: “FIG. 1 is a schematic of a guided wave radar level measurement device in a tank with a single interface.“; Col 3, lines 38-40: “The system uses the principle of time domain reflectometry to determine product levels.“).
Fauveau (‘451) teaches: a measurement unit comprising a transceiver configured to provide a transmit signal, and to receive a reflected signal resulting from a reflection of the transmit signal at a surface of the product; (Col 2, lines 63-67: “The basic guided wave device includes a signal generator/emitter 1 and a signal receiver 2 (the emitter and receiver may be integrated into a single unit as depicted in FIG. 1) and a waveguide 3 operationally connected to the emitter 1 and receiver 2.“; Col 3, lines 36-38: “The electromagnetic wave propagates through the products and is partially reflected at a product interface, with the reflected wave back propagated to the receiver.“). The integrated emitter and receiver unit is a transceiver, and the air/liquid interface 20 (Col 3, lines 33-35) is the surface of the product.
Fauveau (‘451) teaches: a probe connected to the transceiver and configured to propagate the transmit signal towards the surface and to return the reflected signal to the transceiver; (Col 3, lines 1-3: “waveguide 3 may be constructed from flexible cable(s), or solid rod(s) or coaxial probe or other suitable construction known in the art.“; Col 1, lines 22-23: “The device generates an electromagnetic signal which propagates down the waveguide.“; Col 3, lines 36-38, quoted above).
Fauveau (‘451) teaches: control circuitry configured to determine the fill level based on the received reflected signal, the control circuitry being further configured to: (Col 3, lines 7-10: “The guided wave device will either include or work in conjunction with a processor 4 to track and compare time of emission and time of reception“; Col 4, lines 62-65: “In the single pass embodiment (suitable for digital devices where the received signal is stored as a sampled signal) the system tracks the return signal for a first occurrence of a TH1 crossing, (used to determine the total level)“).
Fauveau (‘451) teaches: transmit a signal along the probe; (Col 1, lines 22-23, quoted above; Col 3, lines 40-43: “The system measures the time between the emitted pulse and received pulse (time of flight) and converts the time of flight to a distance measurement by using the signal propagation velocity.“).
Fauveau (‘451) teaches: receive a reflected signal; (Col 1, lines 27-30: “The reflected signals are received, and from these reflected signals, the reflected times can be used to calculate fluid levels and interface relationships, all as well known in the art.“).
Fauveau (‘451) teaches: detect a first peak in the received signal, the first peak having a first amplitude exceeding a first threshold amplitude; (Col 3, lines 62-65: “The system detects the total volume reflection when that signal crosses the threshold level TH1, and also detects the water/oil reflection when that signal crosses the threshold level TH2.“; Col 4, lines 62-65, quoted above). The total volume reflection is a peak in the received signal whose amplitude crosses TH1.
Fauveau (‘451) teaches: determine that no second peak having an amplitude exceeding a second threshold amplitude is detected; (Col 4, lines 50-57: “Shown in FIG. 4 is a representative time signal from the same layered system as in FIG. 3, but now with an emulsion layer separating the oil/water layers. Note that the oil/water reflected signal 12 is smaller that that shown in FIG. 3, and indeed, as shown in FIG. 4, this pulse falls below threshold TH2. In the usual interface detection method, no interface would be found as the applicable threshold TH2 is not crossed.“; Col 5, lines 5-7: “Lacking a TH2 crossing within the time window, the system flags the received signal as a weak interface signal.“; Col 8, lines 19-23 (claim 16): “(c) if no second signal level equal or exceeding said TH2 is detected, monitoring one of said received reflected signals (S3) to detect a third signal level that equals or exceeds a third signal threshold level (TH3), where TH3 is less than TH2“).
Once no TH2 crossing is found, Fauveau (‘451) searches the received signal again for the weak interface echo (Col 6, lines 4-7: “That is, the system is searching the received reflected signal for the weak interface level as an emulsified layer (again, which may or may not be present).“), but that search compares the signal to a lower fixed threshold TH3 rather than applying a sliding window.
Fauveau (‘451) does not explicitly teach, but Weinberg teaches: apply a sliding window peak detection algorithm to the signal to detect a second peak in the signal; and (Page 1, Abstract: “An introduction to the theory of sliding window detection processes, used as alternatives to optimal Neyman-Pearson based radar detectors, is presented.“; Page 1, Section I: “a comparison is then made to determine the presence of a target in the CUT. The next range bin is then (conceptually) tested in the same manner by moving all test cells down one range bin.“; Page 2, Fig. 1 caption: “An illustration of a sliding window detection process. Clutter measurements (Cj) are used to produce a normalised measurement of the clutter level. This is then compared with the cell under test (CUT) and a decision on the presence of a target can be made.“; Page 1, Section I: “These are separated from the CUT by a number of guard cells, whose purpose is to limit the effects of a range spread target.“). Weinberg’s detector moves a window of reference cells, guard cells, and a cell under test along the range profile one range bin at a time and declares a detection at the range bin where the return in the cell under test stands above the background estimated from the neighboring cells, the guard cells keeping the energy of the return itself out of that estimate. The return so detected is a reflection echo standing out from the surrounding signal, which is a peak as interpreted above, and the range bin of the detection is its location. Weinberg’s process is therefore a sliding window peak detection algorithm.
It would have been obvious to a person having ordinary skill in the art (PHOSITA) before the effective filing date of the claimed invention to replace the fixed TH3 weak-interface search of Fauveau (‘451), performed after no TH2 crossing is found, with the sliding window detection process of Weinberg applied along the stored reflection signal. One would have been motivated to do so because Fauveau (‘451) identifies that an emulsion layer produces a diffuse interface echo of reduced and unpredictable strength (Col 2, lines 8-10: “the oil/water interface may be diffuse due to mixing or the presence of an emulsion layer. Such a diffuse interface layer creates a weak return signal.“), while Weinberg teaches that a fixed threshold detector depends on prior knowledge of the signal statistics (Page 3: “This is not a CFAR process since it requires a priori knowledge of the exponential shape parameter.“) and that the sliding window detector does not (Page 1, Section I: “the scheme’s implementation was simpler and did not require an a-priori estimate of the radar target’s strength.“), so that the weak interface echo can be located relative to the local signal level while controlling false detections from noise. There is a reasonable expectation of success because Fauveau (‘451) already stores the received reflection as a sampled signal indexed by time of flight (Col 4, lines 62-65), which is a range profile of the same form processed by Weinberg, and Weinberg’s cell-averaging detector (Page 3, Eq. (6)) requires only summation over the reference cells and a scaled comparison at each window position, operations readily performed by processor 4 of Fauveau (‘451).
Fauveau (‘451) teaches: determining a location of a material interface based on the location of the second peak. (Col 5, lines 11-13: “If the system flags the signal as a weak interface signal, the distance to that level may be calculated“; Col 3, lines 40-43, quoted above). In the combination, the weak interface echo whose distance Fauveau (‘451) calculates is the second peak located by the sliding window detector of Weinberg.
Regarding Claim 7, the limitations are substantially identical to those of claim 1, recited as method steps performed by the control circuitry, and are rejected for the same reasons and with the same combination rationale set forth in the rejection of claim 1.
Regarding Claims 3 and 9, Fauveau (‘451) in view of Weinberg teaches the guided wave radar level gauge according to Claim 1.
Fauveau (‘451) teaches: wherein the control circuitry is further configured to determine that the first detected echo exceeding the first threshold amplitude represent a surface of the product in the tank. (Col 4, lines 62-65: “the system tracks the return signal for a first occurrence of a TH1 crossing, (used to determine the total level)“; Col 2, lines 2-3: “In general, the air or gas/liquid interface references the “total level” in the tank.“). The first TH1 crossing is attributed to the air/liquid interface, which is the product surface.
Regarding Claim 9, the limitation is substantially identical to that of claim 3 and is rejected for the same reasons, Fauveau (‘451) defining the first TH1 crossing as the total level of the product in the tank (Col 4, lines 62-65).
Regarding Claims 4 and 10, Fauveau (‘451) in view of Weinberg teaches the guided wave radar level gauge according to Claim 3.
Fauveau (‘451) teaches: wherein the control circuitry is further configured to determine that the first detected echo after the surface echo exceeding the second threshold amplitude is an interface echo representing an interface of the product in the tank. (Col 4, line 67 - Col 5, line 2: “The system also tracks return signal for a crossing of TH2 within a designated time window after detecting the first TH1 crossing“; Col 5, lines 7-10: “If a suitable crossing of TH2 is found within the designated window, the second time crossing of TH1 is ignored, and the system calculates level on the basis of the TH2 crossing“). The TH2 crossing found after the surface crossing is treated as the liquid/liquid interface echo.
Claim 4 does not require the interface echo to be identified in the same received signal in which claim 1 determines that no second peak exceeding the second threshold amplitude is detected, as set forth in the claim interpretation above. Fauveau (‘451) repeats its threshold search on each new return signal (Col 6, lines 7-8: “After pass 4 (if undertaken), the system would the repeat the process, beginning again at pass 1.“), so that processor 4 identifies the interface by the TH2 rule on a return signal containing a TH2 crossing and, in the combination, applies the sliding window detection of Weinberg on a return signal lacking one. The control circuitry of the combined system is therefore configured to perform both the operations of claim 1 and the operation of claim 4.
Regarding Claim 10, the limitation is substantially identical to that of claim 4, recited as a method step, and is rejected for the same reasons. Under the interpretation set forth above, the determining step of claim 10 is performed on a received signal containing an echo after the surface echo that exceeds the second threshold amplitude, which Fauveau (‘451) processes by its TH2 rule in the repeated measurement passes described above (Col 6, lines 7-8).
Regarding Claims 13 and 14, Fauveau (‘451) in view of Weinberg teaches the method according to Claim 7.
Fauveau (‘451) teaches: A computer program product comprising program code for performing, when executed by the control circuitry, the method of claim 7. and A non-transitory computer-readable storage medium comprising instructions, which when executed by the control circuitry, cause the processing circuitry to perform the method of claim 7. (Col 3, lines 14-17: “Associated with the processor is a memory used to store values or constants (such as expected dielectric constants, time offsets, calibration values, threshold values) for use by the measurement system.“; Col 3, lines 18-21: “The guided wave device may also include electronic hardware or software to process or condition the outgoing signal and/or incoming reflection signal“; Col 5, lines 31-33: “the decision logic and values used for detection of threshold levels could be hardwired without using a processor or memory, but such is not preferred.“). Fauveau (‘451) prefers implementing its detection decision logic on processor 4 with an associated memory rather than in hardwired logic, and that software is program code held in the memory and executed by the control circuitry. The method performed is that of claim 7 as modified by Weinberg, for the reasons given in the rejection of claim 1.
Claims 2 and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Fauveau (US 7,334,451 B1) in view of Weinberg, and further in view of Tian et al. (US 2017/0299641 A1) and Jingsong et al. (CN 109357729 A).
Regarding Claims 2 and 8, Fauveau (‘451) in view of Weinberg teaches the guided wave radar level gauge according to Claim 1.
Fauveau (‘451) does not explicitly teach, but Tian et al. (‘641) teaches: wherein the control circuitry is further configured to determine an energy content of the signal for each position of the sliding window, ([0006]: “Test statistic is generated according to the testing window length by a test statistic generator configured in the sliding window energy detector.“; [0029]: “With any testing window length of the continuously-performed tests greater than one sampling interval, consecutive testing windows can have overlap(s) for the sliding window energy detection test.“; [0053]: “For a test using data in a time window [0, T], the test statistic V of the energy detection can be:“; [0060]: “the sliding window energy detection tests are conducted at a discrete time [k], where k can be 1, 2, 3, etc.“). Tian et al. (‘641) computes an energy test statistic over the samples within the window at each successive window position k.
It would have been obvious to a PHOSITA before the effective filing date of the claimed invention to compute, at each position of the sliding window in the combined system of Fauveau (‘451) and Weinberg, the energy of the sampled reflection signal within the window as taught by Tian et al. (‘641). One would have been motivated to do so because Tian et al. (‘641) directs sliding window energy detection to weak signals under low signal-to-noise conditions ([0045]: “in some cases when a signal to noise ratio (SNR) at detector’s receiver is low, a large testing window length should be particularly required.“) without requiring a model of the signal ([0003]: “Spectrum sensing using energy detection provides low complexity and rapid analysis, and requires no knowledge of transmission signal characteristics.“), and the emulsion echo of Fauveau (‘451) is a weak return of unknown shape (Col 2, lines 8-10), so that integrating energy over the window accumulates the contribution of a smeared, low-amplitude interface reflection that may not produce a single high sample. There is a reasonable expectation of success because Tian et al. (‘641) computes the energy statistic from discrete samples within a window of L samples ([0053], [0060]), and summing the squared samples at each window position is a direct numerical operation on the sampled signal already stored by Fauveau (‘451) (Col 4, lines 62-65).
Fauveau (‘451) does not explicitly teach, but Jingsong et al. (‘729) teaches: and to determine the location of the interface as the window position having the highest energy content. ([0015]: “If the peak value of the peak with the largest peak is found in the range T1 to the maximum range Tmax as the reflected echo from the tip of the probe to the separated liquid surface, the coordinate position T2 corresponding to the peak is selected, and the distance D2 from the tip of the probe to the separation liquid surface is calculated.“; [0047]: “pre-processing uses the moving average filtering method to filter the data to eliminate glitch.“). Jingsong et al. (‘729) takes the position of the largest response in the search range below the surface echo as the interface location. In the combined system, the per-position response is the window energy taught by Tian et al. (‘641), so selecting the largest response is determining the interface location as the window position having the highest energy content.
It would have been obvious to a PHOSITA before the effective filing date of the claimed invention to select, as the interface location in the combined system of Fauveau (‘451), Weinberg, and Tian et al. (‘641), the window position having the greatest computed energy as taught by Jingsong et al. (‘729). One would have been motivated to do so because Jingsong et al. (‘729) addresses the same oil/water interface measurement with a guided wave radar level gauge ([0006]) and teaches that, once the surface echo at T1 is identified, the interface is taken as the largest response within the bounded range T1 to Tmax ([0015]), which yields a single interface position at the point where the window coincides most fully with the interface reflection. There is a reasonable expectation of success because Jingsong et al. (‘729) applies this largest-response selection to a sampled, moving-average-filtered guided wave radar echo signal ([0047-0048]), and applying the same maximum selection to the array of window energies of the combined system is a single comparison over stored values on processor 4 of Fauveau (‘451).
Regarding Claim 8, the limitations are substantially identical to those of claim 2, recited as method steps, and are rejected for the same reasons and with the same combination rationale set forth in the rejection of claim 2.
Claims 5, 6, 11, and 12 are rejected under 35 U.S.C. 103 as being unpatentable over Fauveau (US 7,334,451 B1) in view of Weinberg, and further in view of Frövik et al. (US 2019/0128727 A1).
Regarding Claims 5 and 11, Fauveau (‘451) in view of Weinberg teaches the guided wave radar level gauge according to Claim 1.
Fauveau (‘451) teaches that the interface level calculated from a threshold crossing is corrected by a bias (Col 5, lines 9-10: “the system calculates level on the basis of the TH2 crossing, including application of suitable bias“; Col 4, lines 30-32: “Timing must be accounted for when monitoring for signal crossings, since two different threshold levels will lead to two different measured time.“) and converts time of flight to distance using a propagation velocity determined from the dielectric constants of the products (Col 3, lines 45-47: “The propagation velocity in a particular fluid is inversely proportional to the square root of the dielectric constant of that fluid.“; Col 4, lines 3-5: “can be determined based upon dielectric constants of the liquids in the tank (if known beforehand)“), but does not describe adjusting a location already determined for the material interface by a correction derived from the dielectric properties of the product.
Fauveau (‘451) does not explicitly teach, but Frövik et al. (‘727) teaches: wherein the control circuitry is further configured to adjust the determined location of the material interface based on known dielectric properties of the product in the tank. ([0090]: “The second interface level is then determined, in step 709, based on the second threshold position zTH2 and a predetermined second offset distance Δz2 along the probe 7 from the second threshold position zTH2 towards the second probe end 11.“; [0091]: “The echo pulse shape 65 of the reflection at the second interface 22 can be calculated based on known propagation properties of the probe 7 and the dielectric constants of the second substance 14, and the third substance 16 in the tank 4.“; [0020]: “Furthermore, the first offset may depend on at least one material property of the second substance, such as the dielectric constant of the second substance.“). Frövik et al. (‘727) determines the position of the interface echo along the probe and then shifts that position by an offset distance derived from the dielectric constants of the products on either side of the interface ([0092]: z2 = zTH2 + Δz2), which adjusts the determined location of the material interface based on known dielectric properties of the product.
It would have been obvious to a PHOSITA before the effective filing date of the claimed invention to derive the correction applied to the interface location in the combined system of Fauveau (‘451) and Weinberg from the known dielectric constants of the products in the tank as taught by Frövik et al. (‘727). One would have been motivated to do so because Fauveau (‘451) already recognizes that a level calculated from a detected echo position must be corrected by a bias, and Frövik et al. (‘727) teaches for the same guided wave radar interface measurement that the offset between a detected echo position and the true interface depends on the shape of the interface echo, which is governed by the dielectric constants of the adjoining substances ([0079], [0091]), so that basing the correction on those known properties keeps it accurate for the products actually stored rather than relying on a single fixed bias. There is a reasonable expectation of success because Fauveau (‘451) already computes product levels from propagation velocities determined from dielectric constants of the liquids known beforehand (Col 3, lines 45-47; Col 4, lines 3-5) and stores those constants in the memory associated with processor 4 (Col 3, lines 14-17), and Frövik et al. (‘727) shows that the offset is computed from a straightforward echo-shape model ([0080-0082]), so applying a dielectric-dependent offset to the interface location located by the combined system is a direct calculation on stored values.
Regarding Claim 11, the limitation is substantially identical to that of claim 5, recited as a method step, and is rejected for the same reasons and with the same combination rationale set forth in the rejection of claim 5.
Regarding Claims 6 and 12, Fauveau (‘451) in view of Weinberg teaches the guided wave radar level gauge according to Claim 1.
Fauveau (‘451) teaches that its thresholds are settable and are chosen to account for the different expected reflection strengths (Col 5, lines 27-28: “It is preferred that the threshold levels be settable, and the delays also be settable.“; Col 1, lines 62-64: “When two reflections are expected, two different threshold values are preferred to account for the differences in the signal strengths of the reflections.“), but does not describe setting the thresholds based on propagation properties of the probe.
Fauveau (‘451) does not explicitly teach, but Frövik et al. (‘727) teaches: wherein the first threshold amplitude and the second threshold amplitude are set based on propagation properties of the probe and on known properties of the product in the tank. ([0094]: “For example, other probe configurations and other substances in the stratified substance composition may result in different selections of the threshold signal strengths and different estimations of the offset distances.“; [0079]: “The echo pulse shape of the reflection at the first interface 20 can be calculated based on known propagation properties of the probe 7 and the dielectric constants of the first substance 12 and the second substance 14 in the tank 4.“). Frövik et al. (‘727) selects its first and second threshold signal strengths TH1 and TH2 ([0077], [0089]) according to the probe configuration and the substances in the tank, the expected echo being calculable from the propagation properties of the probe and the dielectric constants of the products.
It would have been obvious to a PHOSITA before the effective filing date of the claimed invention to set the TH1 and TH2 values of the combined system of Fauveau (‘451) and Weinberg based on the propagation properties of the installed probe and the known properties of the products as taught by Frövik et al. (‘727). One would have been motivated to do so because Fauveau (‘451) selects TH1 and TH2 to bracket the expected strengths of the surface and interface reflections (Col 1, line 64 - Col 2, line 1), those strengths depend on the dielectric contrast at each interface (Col 1, lines 34-37) and on how the probe propagates the pulse, and Frövik et al. (‘727) teaches for the same type of guided wave radar interface gauge that the probe configuration and the substances govern the expected echo and therefore the threshold selection ([0079], [0094]), so that the thresholds remain matched to the echo amplitudes actually expected when the probe type or stored product changes. There is a reasonable expectation of success because Fauveau (‘451) stores its threshold values in memory and permits them to be set at the factory or in the field (Col 3, lines 14-17; Col 5, lines 27-30), and Frövik et al. (‘727) shows that the expected echo can be calculated from probe propagation properties and dielectric constants ([0079-0081]), so storing thresholds derived in that manner requires no structural change to the Fauveau gauge.
Regarding Claim 12, the limitation is substantially identical to that of claim 6, recited as a method step, and is rejected for the same reasons and with the same combination rationale set forth in the rejection of claim 6.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Linden et al. (US 2014/0104098 A1) discloses a guided wave radar interface transmitter whose controller operates in a medium identification mode when the interface pulse is not received. It is pertinent to the claimed processing performed when no interface echo is found by ordinary detection.
Edvardsson (US 2014/0084945 A1) discloses determining a material interface level using a guided wave radar probe having reference impedance transitions above and below the interface. It is pertinent to guided wave radar interface determination in tanks containing layered products.
Flasza et al. (US 2015/0084809 A1) discloses measuring and profiling an emulsion layer between two media using reflected signal energy along a coated guided wave radar probe. It is pertinent to the emulsified interface problem addressed by the instant application and to energy-based analysis of the reflected signal.
Weber et al. (US 2014/0210488 A1) discloses filling level measurement of layered media, such as foam over liquid, in which border transitions are recognized from the integral over the reflected signal curve. It is pertinent to energy-based localization of an indistinct interface.
Taheri et al. (US 2017/0211963 A1) discloses determining temporal coordinates of overlapping reflected radar pulses from thin layers by comparing candidate reference pulses at successive positions and minimizing residual signal energy. It is pertinent to locating weak or overlapping interface echoes by evaluating the signal at successive positions.
Savard et al. (US 2016/0117426 A1) discloses pulsed radar interface determination by iteratively comparing a measured interface pulse with a model-generated pulse based on refractive indices and layer thickness. It is pertinent to the use of known dielectric properties in determining the interface location.
Daigle (US 2009/0257311 A1) discloses correcting echo pulse error in a pulse-echo ranging system by fitting a parabola to the leading edge of the echo. It is pertinent to precise echo peak localization in level measurement.
Lovegren et al. (US 6,445,192 B1; family member CN 1422385 A) discloses detecting closely spaced material interfaces with a microwave level transmitter by identifying a first peak, an intervening valley, and a second peak in a double-peaked echo pulse, the second peak being accepted when it exceeds a second threshold. It is pertinent to interface detection when the interface echo is not separately resolved by conventional threshold detection.
Fengyun et al. (CN 106052801 A) discloses a guided wave radar level meter applying wavelet transform analysis to fluctuating transient echo signals. It is pertinent to processing of unstable echoes in level gauging.
Diede et al. (US 6,198,424 B1) discloses a time domain reflectometry radar level transmitter in which a threshold controller detects the surface and interface reflections using separate first and second thresholds and computes the level of the lower product using the dielectric constant of the upper product. It is pertinent to the claimed two-threshold surface and interface detection and to determining the interface location based on dielectric properties of the product.
Kejun et al. (CN 104374447 A) discloses guided wave radar echo processing in which echoes are detected from the first derivative of a moving-average-filtered signal and the level echo is selected by a confidence value computed from echo amplitude, width, and rate of change, including where the level echo is smaller than the preceding noise. It is pertinent to locating a weak echo in a guided wave radar signal when maximum-amplitude detection fails.
Backstrom et al. (US 2016/0097669 A1) discloses guided wave radar level finding in which a pulse model spanning a window of samples is compared with the echo curve at each sample position and the material level or interface is located at the minimum of the resulting prediction error. It is pertinent to the claimed sliding window detection of an interface echo and to replacing user-defined threshold peak finding in interface measurement.
Jingsong et al. (CN 109357729 B) is the granted family member of the relied-upon CN 109357729 A and discloses the same surface and interface peak selection and dielectric correction. It is cited for completeness of the family record.
Frövik et al. US 10,816,384 B2, cited in the European search report, is the granted family member of Frövik et al. (US 2019/0128727 A1). It discloses determining interface levels from threshold positions and offset distances in a stratified substance composition.
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/REMASH R GUYAH/Examiner, Art Unit 3648
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