Ex Parte Walker et alDownload PDFPatent Trial and Appeal BoardNov 7, 201712543452 (P.T.A.B. Nov. 7, 2017) Copy Citation United States Patent and Trademark Office UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O.Box 1450 Alexandria, Virginia 22313-1450 www.uspto.gov APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. 12/543,452 08/18/2009 William F. Walker 1036.161US1 7361 21186 7590 11/09/2017 SCHWEGMAN LUNDBERG & WOESSNER, P.A. P.O. BOX 2938 MINNEAPOLIS, MN 55402 EXAMINER AKAR, SERKAN ART UNIT PAPER NUMBER 3786 NOTIFICATION DATE DELIVERY MODE 11/09/2017 ELECTRONIC Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the following e-mail address(es): uspto@slwip.com SLW @blackhillsip.com PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE BEFORE THE PATENT TRIAL AND APPEAL BOARD Ex parte WILLIAM F. WALKER, MICHAEL I. FULLER, KARTHIK RANGANATHAN, JOHN A. HOSSACK, and TRAVIS N. BLALOCK1 Appeal 2016-008454 Application 12/543,452 Technology Center 3700 Before ERIC B. GRIMES, ULRIKE W. JENKS, and DEVON ZASTROW NEWMAN, Administrative Patent Judges. JENKS, Administrative Patent Judge. DECISION ON APPEAL This is an appeal under 35 U.S.C. § 134(a) involving claims to a system for generating pulse-echo images and a method of processing the generated images. The Examiner rejects the claims as obvious. We have jurisdiction under 35 U.S.C. § 6(b). We REVERSE. 1 According to Appellants, the Real Party in Interest is the University of Virginia Patent Foundation. App. Br. 2. Appeal 2016-008454 Application 12/543,452 STATEMENT OF THE CASE The Specification describes the general workings of an ultrasound system as follows: Ultrasound waves emitted by the transducer array impact objects in the field that the beam is focused to. Reflected ultrasound waves (echoes) are reflected off of the objects impacted by the emitted ultrasound waves. Echoes that are reflected back to the transducer array are transduced from ultrasonic waves to electrical signals (received signals). The received signals are amplified, filtered, and then, in almost all cases, digitized by analog to digital converters (A/Ds). These digitized signals are then focused and apodized by the receive beamformer, followed by image processing and scan conversion for display on a monitor. Spec. | 62. The weak amplitude of the received signal is a problem in these types of systems and requires amplification before digitizing the signal. This amplification, however, also results in noise being amplified as well. Spec. 1 8. One way to improve the signal-to-noise ratio is to use coded excitation. Using coded excitation, the base excitation pulse is convolved with a code that lengthens the transmitted pulse while complying with FDA regulations that goyem [sic, govern] peak pressure. The resulting longer ultrasound pulse contains more energy, which translates into stronger echoes from targets and a higher SNR in the received signal. The received signal is then “compressed” to eliminate the lengthening effect of the code, while still preserving the extra energy. There are several strategies to compress the received signal: examples include convolution with a matched filter that corresponds to the code or 2 See the Specification filed Aug. 18, 2009 (“Spec.”). 2 Appeal 2016-008454 Application 12/543,452 with a custom “mismatched filter” to shape the compressed pulse into one having preferred characteristics. Spec. 111. The Specification explains that “coded excitation increases the length of the acoustic pulse and since prior methods for implementing coded excitation perform the decoding in the digital domain, the number of samples that must be acquired and digitized to form a C-scan image increases as a multiple of the code length.” Spec. 113. To overcome these processing issues the Specification describes the use of an “analog decoder [that] decodes the received electrical signal using coded excitation to provide decoded analog samples and the analog-to-digital converter converts the decoded analog samples to decoded digital samples.” Spec. 120. Claims 1,2, 8—32, and 38—53 are on appeal, and can be found in the Claims Appendix of the Appeal Brief. Claim 1 is representative of the claims on appeal, and reads as follows (emphasis added): 1. A pulse-echo imaging system comprising: a pulse generation circuit configured to provide electrical signals representative of a transmit code sequence; a transducer configured to receive the electrical signals provided by the pulse generation circuit as pulses using coded excitation according to said transmit code sequence, and to transduce said electrical signals to pulses of energy other than electrical signals; said transducer being further configured to receive echoes of said pulses of energy other than electrical signals and convert the echoes to received electrical signals; and a receive circuit configured to: receive said received electrical signals; perform analog sampling of the received electrical signals; perform analog decoding of the received electrical signals using information about the coded excitation and using an analog decoder circuit; and provide a weighted, summed digital signal using 3 Appeal 2016-008454 Application 12/543,452 information obtained from the analog sampling and the analog decoding. The only other independent claims, claims 31 and 39, recite similar limitations with respect to analog decoding. Specifically, claim 31 recites “perform[ing] analog decoding of the received electrical signals using information about the coded excitation and using an analog decoder circuit;” while claim 39 recites “provid[ing] analog decoding of the samples using an analog decoder circuit including using information about the coded excitation.” Appellants request review of the rejection of claims 1, 2, 8—32, and 38—53, and specifically argue the following grounds of rejection: I. claims 1, 2, 8, 12, 20, 21, 28, 29, 31, 32, 38-43, and 50-53 under 35 U.S.C. § 103(a) as unpatentable over Chiao3 in view of Fuller4 and Hao5 (Appeal Br. 10-17); II. claim 9 under 35 U.S.C. § 103(a) as unpatentable over Chiao, Fuller, and Hao as applied to claim 1 and further in view of Johnson6 (id. at 17—18); and III. claims 16 and 48 under 35 U.S.C. § 103(a) as unpatentable over Chiao, Fuller, and Hao as applied to claims 1 and 39 and further in view of Savord7 (id. at 18—19).8 3 Chiao et al., US 6,210,332 Bl, issued April 3, 2001 (“Chiao”). 4 Fuller et al., A Portable, Low-Cost, Highly Integrated, 3D Medical Ultrasound System, IEEE ULTRASONICS SYMPOSIUM 38-41 (2003)(“Fuller”). 5 Hao et al., US 2005/0054925 Al, published March 10, 2005 (“Hao”). 6 Johnson et al., US 2007/0282200 Al, published Dec. 6, 2007 (“Johnson”). 7 Savord, US 6,013,032, issued Jan. 11, 2000 (“Savord”). 8 In addition to the rejections listed above, claims 19, 26, and 27 stand 4 Appeal 2016-008454 Application 12/543,452 Since all of the rejections rely upon the teaching of Chiao, Fuller and Hao, we consider the rejections together. The Examiner finds that “Chiao teaches [a] system and method for pulse-echo medical imaging . . . using coded excitation according to said transmit code sequence . . . and to transduce said electrical signals to pulses of energy other than electrical signals (ultrasound transducers are known to convert electric energy to acoustic energy; Host computer [] determines the conditions under which the acoustic pulses will be transmitted . . .).” Final Act.* * * * * * 9 3^4. The Examiner finds that “Chiao does not teach perform[ing] analog sampling and analog decoding of the received electrical signals using information about the coded excitation; and configured to provide a weighted, summed digital signal using information obtained from the analog sampling and the analog decoding.” Id. at 5. The Examiner relies on Fuller to teach analog sampling and analog decoding of a coded excitation signal. See Final Act. 5, see also id. at 25 (“the ‘filter’ circuitry [of Fuller] is interpreted as ‘analog decoder’”). The Examiner concludes that it would have been obvious to modify the method of Chiao with the analog decoding taught by Fuller because this relaxes analog-to-digital converter processing and memory constraints of digital processing. See id. at 7. rejected under 35 U.S.C. § 103(a) over Chiao, Fuller, Hao, Savord, and Lipshutz (US 5,469,851, issued Nov. 28, 1995) (claim 19) or Chiao, Fuller, Hao, and Lipshutz (claims 26 and 27). Appellants argue these claims are not obvious for the same reasons independent claim 1, from which they depend, is not obvious (Appeal Br. 16). For the reasons discussed below, we agree with Appellants’ position. 9 Final Office Action mailed Nov. 20, 2014 (“Final Act.”). 5 Appeal 2016-008454 Application 12/543,452 Appellants contend that Fuller does not teach analog decoding as claimed. Appeal Br. 15; see also id. at 17 (“Fuller and Hao similarly fail to disclose, teach, or suggest such analog sampling in the context of coded excitation”). Furthermore, Appellants contend that “[t]he Examiner explicitly and repeatedly mischaracterizes ‘coded excitation’ and the corresponding decoding of such coded excitation as somehow being the same as beamforming.” Reply Br. 2, see also Id. at 4 (“[T]he Examiner erroneously blurs the distinction between beamforming and coded excitation, and also the distinction between band-pass (e.g., linear) filtering and compression (e.g., non-linear) filtering”). The issue is: Does the preponderance of evidence of record support the Examiner’s conclusion that Fuller’s system is an analog decoder of a received electrical signal that uses information about the coded excitation? Findings of Fact FF1. Chiao teaches flow imaging using coded excitation. See Chiao, Abstract. Figure 1, reproduced below, shows a conventional ultrasound imaging system. 6 Appeal 2016-008454 Application 12/543,452 Fig. 1 shows a “host computer 20, transmitter 14 drives transducer array 10 such that the ultrasonic energy is transmitted as a directed focused beam. . . . Host computer 20 determines the conditions under which the acoustic pulses will be transmitted.” Id. at 5:29-58; see Ans. 3—A. FF2. Chiao teaches using coded excitation. “Coded excitation is a well- known radar technique used to increase signal-to-noise ratio in situations where the peak power of a transmitted signal cannot be increased but the average power can.” Chiao 2:57—60. The basic concept of the single-transmit coded excitation comprises modulating a specially designed code sequence based on a transmit burst (base sequence) of length P. A coded pulse sequence of n bursts is often referred to as an n-chip code. The coded pulse sequence, which has a length nxP, enables a larger acoustic dosage or a shorter base sequence to be used to interrogate the flowing blood. Id. at 6:63—7:2. “Preferred single-transmit codes include Barker codes and non-Barker codes such as the length-8 code [1,1,1,-1,1,-1,-1,1].” Id. at 7:18-21. 7 Appeal 2016-008454 Application 12/543,452 FF3. Chiao teaches that “[a] single coded waveform is transmitted and the received waveform is convolved with the decoding filter impulse response to compress the waveform energy into a small time interval. The decoding filter may be a matched filter (wherein the filter coefficients are the same as the transmit code) or a mismatched filter.” Id. at 7:9-15. FF4. The Examiner finds that “Chiao does not teach perform[ing] analog sampling and analog decoding of the received electrical signals using information about the coded excitation.” Final Act. 4; see also Ans. 4 (“Chiao does not teach analog sampling and analog decoding of coded excitation since the signals are digitized at the receiver 16”). FF5. Fuller teaches an integrated circuit that uses Direct Sampled In Phase/Quadrature (DSIQ) beamforming. Fuller 38. The receive circuit is shown in Figure 2, reproduced below. T«M)MN«l»r TX'RX TX TX Preamp-' KPr m MS Keaisttf Afpsy Switch Arrtj* Gctterstor Amp Samptef <10 KHz Fite Figure 2 shows the system block diagram showing parallel channels each consisting of protection circuitry, a preamp, a bandpass filter, a 8 Appeal 2016-008454 Application 12/543,452 DSIQ sample-and-hold (S/H) stage, and a distributed analog-to-digital converter. Fuller 38. The core of the DSIQ beamforming technique lies in the sample-and-hold stage, which performs the sampling of the in-phase and quadrature components of the signal. The S/H stage consists of two parallel channels sampled 1/4 period apart based on the transducer center frequency. This technique reduces the digitization rate toward the pulse repetition frequency (PRF), drastically relaxing ADC [(analog-to-digital converter)] and memory constraints. Id. at 40; see Final Act. 6—7. FF6. Hao teaches “tissue harmonic imaging using an ultrasound machine. Coded pulses and the phase inverted version of the said coded pulses with time bandwidth greater than 1 are transmitted into the tissue.” Hao, Abstract; see 137. Hao explains that “the coded excitation waveform of the transmit signal does not need to be very long, so that, when combined with pulse inversion, and the above mentioned effects, decoding is not necessary.” Id. 170. FF7. The Specification provides that “the analog decoder decodes the received electrical signal using coded excitation to provide decoded analog samples and the analog-to-digital converter converts the decoded analog samples to decoded digital samples.” Spec. 120. [T]he analog decoder comprises a switch and a summing device; wherein the received electrical signals generate[d] using coded excitation are directed down two circuit paths of the two-level filter, wherein scaled samples are produced by one of the two circuit paths multiplying the signals by +1 and the other of the two circuit paths multiplying the signals by -1, and, 9 Appeal 2016-008454 Application 12/543,452 depending upon whether a resulting signal coefficient is +1 or -1, the switch selects one of the circuit paths and passes the scaled sample to the summing device; wherein the summing device sums the scaled samples received to yield a decoded sample. Id. 124. Principle of Law “An examiner bears the initial burden of presenting a prima facie case of obviousness.” In re Huai-Hung Kao, 639 F.3d 1057, 1066 (Fed. Cir. 2011). Analysis The Examiner’s position is that “[sjignal compressions or band-pass filtering is very common and frequently used for signal modification (decoding).” Ans. 8. The Examiner finds that because the codes are not specified in the claims, any signal received by the receiver in which “the amplitude is filtered or the time delay is adjusted to obtain the transmitted frequency amplitude (which both amplitude and the time delay can be interpreted as decoding).” Id. at 3. Appellants contend that Fuller does not disclose analog decoding of a coded signal. Appeal Br. 15. “[0]ne of ordinary skill in the art would readily appreciate that such coded excitation involves dispersing the energy of an excitation pulse over a broader pulse width for transmission - a non linear transformation of the excitation pulse - and then compressing the received pulse to eliminate the lengthening effect.” Reply Br. 3. The rejection “fails to show that the recited ‘coded excitation’ coupled with the recited ‘analog decoding’ using information about the ‘coded excitation’ and 10 Appeal 2016-008454 Application 12/543,452 using an ‘analog decoder circuit’ is broad enough to encompass such beamforming.” Reply Br. 3; see also Appeal Br. 11. Chiao teaches imaging using coded excitation. FF1. Chiao explains that coded excitation comprises modulating a specially designed code sequence such as Baker codes or non-Baker codes onto a transmit burst that allows for a larger acoustic dosage. FF2. Chiao teaches that the decoding filter may be a matched filter, having the same coefficients as the transmit code, or that the filter can be mismatched. FF3. The Examiner finds, however, that Chiao does not perform analog decoding. FF4. In other words, Chiao’s filtering method uses digitally compiled data before applying the various filter parameters. Therefore, the Examiner relies on Fuller’s teaching to teach analog filtering (decoding). Fuller teaches an integrated circuit that uses DSIQ beamforming. FF5. The receiving circuit of Fuller contains a bandpass filter and a DSIQ sample-and-hold (S/H) stage. FF5. The Examiner finds that “Fuller clearly teaches analog receiving and analog signal processing along with the signal filtering where the filters are used as a decoder.” Ans. 5. Specifically, the Examiner finds that a bandpass filter is an analog decoder. See Ans. 5. To support the position that filters are known to be used as decoders, the Examiner cites Wang10 in support. Ans. 6. Hao, also cited by the Examiner, uses coded excitation wave forms but the excitation code used is not long enough to require any decoding of the signal. FF6. 10 Wang et al., Coded EXcitation with Spectrum Inversion (CEXSI) for Ultrasound Array Imaging, 50 IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 805-823 (2003) (“Wang”). 11 Appeal 2016-008454 Application 12/543,452 On this record, we find that Appellants have the better position. We recognize that Fuller teaches analog processing of a received signal prior to subjecting the signal to digital processing with the analog-to-digital converter. FF5. Fuller explains that the advantage of this technique is that it “reduces the digitization rate toward the pulse repetition frequency (PRF), drastically relaxing ADC [(analog-to-digital converter)] and memory constraints.” FF5. Fuller’s sample and hold (S/H) stage uses two channels that are set apart by A period. FF5. Fuller, however, does not teach adjusting the filter processing of the received signal based on information about the coded excitation that is applied to the original signal transmitted by the transducer.11 Hao also does not provide insight into Fuller’s filter processing and does not establish that Fuller’s analog filtering uses any information based on any coded excitation applied to the transmission pulse. Accordingly, we agree with Appellants’ position that the combination of 11 We note that Wang, which is not a basis of the rejection, uses inverse filters in conjunction with a band pass filter to decode a coded excitation spectrum. Wang explains that “[cjoded-excitation, which transmits a longer pulse with larger energy, is an option. However, decoding (i.e., a compression filter to produce the response from the original pulse) is demanding.” Wang 805, col. 2, first paragraph. “Traditional coded excitation uses chirp codes, M-sequence, or Barker codes. They are decoded with correlation-based procedures such as matched filtering or mismatched filtering.” Wang 805, col. 2, fifth paragraph. Wang discloses using an inverse filter in conjunction with a band pass filter to decode a coded- excitation spectrum. Wang 812, see Fig 9. “The key point is that our inverse filter is derived from the 21 -bit code and not the burst encoding it. This eliminates the tricky issue of inverting the burst spectrum in previous inverse filter approaches.” Wang 809, col. 2, fourth paragraph, and Fig 5. Notably, Wang teaches selecting the inverse filter based on the code added to the transmission signal and not the entire burst containing the code. 12 Appeal 2016-008454 Application 12/543,452 references does not teach the limitation of “performing] analog decoding of the received electrical signals using information about the coded excitation and using an analog decoder circuit” as claimed. Even if we agree with the Examiner that Fuller discloses analog filtering and decoding of a received signal, we do not find that the process in Fuller takes into account any coded excitation information that is applied to the transmission pulse of a pulse-echo imaging system. We recognize, but are not persuaded by, the Examiner’s position that the claims are broad in that they do not recite specific excitation code that is incorporated in the transmission code sequence. See Ans. 3. Coded excitation is a way to increase the average power of a signal by including a code sequence into the transmission burst. FF2. The claim does not need to recite a specific excitation code in order for such a code to be considered in the processing phase of the received signal of a pulse-echo system. The processing phase of a pulse-echo signal does not occur in isolation, rather it is part of a system that both produced the sound signal that is applied to a study area and also captures the reflected signal from that area. Thus, a system that does not add an excitation code signal to the transmission burst would not include a way of processing a received signal that takes such a code into account. We conclude that the preponderance of the evidence of record does not support the Examiner’s conclusion that the combination of Chiao, Fuller, and Hao discloses an imaging system and a method having all limitations of independent claims 1,31, and 39 and dependent claims thereto. We also reverse the rejections under 35 U.S.C. § 103(a) of any claims that rely on the teachings of the combination of these references. 13 Appeal 2016-008454 Application 12/543,452 SUMMARY We reverse the rejection of all claims under 35 U.S.C. § 103(a). REVERSED 14 Copy with citationCopy as parenthetical citation