Apple Inc v. Andrea Electronics Corp

1. Case Identification

• Case #: IPR2017-00627
• Patent #: 6,363,345
• Filed: January 9, 2017
• Petitioner(s): Apple Inc.
• Patent Owner(s): Andrea Electronics Inc.
• Challenged Claims: 1-25, 38-47

2. Patent Overview

• Title: System, Method and Apparatus for Cancelling Noise
• Brief Description: The ’345 patent discloses systems and methods for reducing noise from an audio signal using a spectral subtraction technique. The described improvement involves using a threshold detector for each frequency bin to distinguish noise from speech, which allegedly eliminates the need for a conventional "voice switch" that detects noise-only frames.

3. Grounds for Unpatentability

Ground 1: Anticipation by Helf - Claims 1-7, 9-11, 13-14, 21, 23, 38-41, and 43 are anticipated by Helf under 35 U.S.C. §102.

• Prior Art Relied Upon: Helf (Patent 5,550,924).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Helf discloses every element of the challenged independent claims. Helf describes a system for reducing background noise that converts an audio signal into frequency components (bins), uses a noise estimation process to set a threshold for each bin, and detects noise by comparing the magnitude of each component to the corresponding threshold. Helf’s "running minimum" estimation technique, which tracks a minimum signal value over a 10-second interval to estimate noise, was asserted to meet the limitations for tracking "current minimum" and "future minimum" values in dependent claims.
  • Key Aspects: As an alternative, Petitioner argued that even if Helf were interpreted as operating on signal power instead of magnitude, the claims would be obvious. A POSITA would have understood that magnitude and power are directly related (power is magnitude squared) and would have found it an obvious variation to configure Helf to operate on signal magnitude to achieve the same result.

Ground 2: Obviousness over Helf and Martin - Claims 6, 8-9, 12, 25, 42, and 46 are obvious over Helf in view of Martin.

• Prior Art Relied Upon: Helf (’924 patent), Martin ("An Efficient Algorithm to Estimate the Instantaneous SNR of Speech Signals," Eurospeech 1993).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Martin cures any potential deficiencies in Helf regarding certain dependent claims. For claim 8, which requires updating a noise estimate when the current signal value is less than the current noise estimate, Martin explicitly teaches this step, stating that "If the actual smoothed power is smaller than the estimated noise power... the noise power is updated immediately." For claim 12, Martin teaches smoothing the signal value before comparing it to a threshold. For claims 25 and 46, Martin discloses using its noise estimation technique with adaptive microphone arrays, a feature not disclosed in Helf.
  • Motivation to Combine: A POSITA would combine Martin's teachings with Helf to improve the speed and accuracy of Helf's noise estimation algorithm, especially during continuous speech. Martin's algorithm is designed to track noise levels without an explicit speech detector, aligning with the goals of Helf. Helf itself suggests that modifications would be apparent to a skilled person, providing a motivation to look to analogous art like Martin for improvements.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success in combining the references, as it involved applying Martin's known noise-floor tracking improvements to the known spectral subtraction framework of Helf to achieve a more robust system.

Ground 3: Obviousness over Helf and Boll - Claims 17-20 and 47 are obvious over Helf in view of Boll.

• Prior Art Relied Upon: Helf (’924 patent), Boll ("Suppression of Acoustic Noise in Speech Using Spectral Subtraction," IEEE 1979).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground focused on claims requiring a "residual noise processor." Petitioner argued that while Helf identifies the problem of residual "twinkling" sounds after initial noise subtraction, it does not explicitly teach a solution. Boll, a seminal paper on spectral subtraction admitted as prior art by the ’345 patent, explicitly teaches applying a "residual noise reduction" process after the main subtraction step to remove such artifacts. Boll's process involves steps like replacing noise values with a minimum magnitude from adjacent frames and using a speech activity detector (voice switch), which map directly to the limitations of claims 17-20.
  • Motivation to Combine: A POSITA, recognizing the "twinkling" noise problem in Helf's system, would have been motivated to implement a known solution. They would combine Boll's well-established residual noise reduction technique into Helf's spectral subtraction framework to predictably reduce unwanted audio artifacts and improve signal quality.
  • Expectation of Success: The combination was presented as a routine application of a known solution (Boll's residual noise reduction) to a known problem (Helf's twinkling artifacts) with predictable results.

• Additional Grounds: Petitioner asserted additional obviousness challenges, including combinations of Helf and Arslan (for claims related to Wiener filters); Helf, Boll, and Arslan (for two-dimensional smoothing); and Helf and Uesugi (for computationally efficient magnitude approximations).

4. Key Claim Construction Positions

• "magnitude": Petitioner argued this term should be construed broadly to include both the signal's actual magnitude and an approximation of its magnitude. This construction is supported by the specification and was argued to be consistent with the Patent Owner's positions in prior litigation.
• "current minimum value" / "future minimum value": Petitioner proposed broad constructions for these terms, arguing they are not limited to calculation over a "predetermined time period" except where explicitly recited (e.g., in claim 10). The proposed construction for "current minimum value" was a "value representing the minimum value of a frequency bin that is used to set the threshold for the bin." This broad reading was central to the argument that Helf's noise estimation process met these limitations.

5. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-25 and 38-47 as unpatentable.