Prior art

Based on a review of the citations for US patent 8,306,815, the following prior art references are identified as most relevant to the patent's claims. The analysis focuses on the potential for anticipation under 35 U.S.C. § 102, which requires a single prior art reference to disclose each and every element of a claimed invention.

The core inventive concept of US 8,306,815, particularly in its independent claims, involves a specific dual-feedback control architecture:

1. An analysis signal, containing non-semantic information about the speech input (e.g., noise, pitch, location), is used to control a speech output unit.
2. A recognition result, containing the semantic content (the recognized words), is used to control the signal pre-processor unit.

The following prior art references touch upon key elements of this system but do not appear to disclose the complete, specific architecture claimed.

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1. US 2004/0064315 A1

• Full Citation: US Patent Application Publication No. 2004/0064315 A1, "Acoustic confidence driven front-end preprocessing for speech recognition in adverse environments."
• Publication Date: April 1, 2004
• Brief Description: This document describes a speech recognition system that calculates an "acoustic confidence measure" based on the signal-to-noise ratio (SNR) of an input audio signal. This measure, which is a form of non-semantic analysis, is then used to adaptively control the front-end pre-processing of the signal. For example, more aggressive noise reduction can be applied when acoustic confidence is low.
• Potential Anticipation of Claims:
  • This reference discloses using a non-semantic analysis of an input signal (the "acoustic confidence measure," analogous to the "analysis signal" in patent 8,306,815) to control a signal pre-processor.
  • This anticipates the general concept of adapting pre-processing based on signal quality. However, it appears to differ from the specific architecture of Claim 1, which requires the analysis signal to control the output unit and the recognition result to control the pre-processor.
  • It does not appear to disclose the complete feedback loop structure of independent claims 1, 20, 22, and 23.

2. US 5,524,169 A

• Full Citation: US Patent No. 5,524,169 A, "Method and system for location-specific speech recognition," assigned to International Business Machines Corporation (IBM).
• Issue Date: June 4, 1996
• Brief Description: This patent details a system that improves speech recognition by using the speaker's physical location. The system determines where the user is (e.g., driver vs. passenger seat in a car) and selects a location-specific acoustic model or grammar to process the speech, thereby increasing accuracy.
• Potential Anticipation of Claims:
  • This reference strongly anticipates the use of speaker location, a non-semantic characteristic, to control a speech dialog system. This is directly relevant to dependent claims 8 and 9 of patent 8,306,815.
  • It also anticipates the concept of using this analysis to control the speech recognition unit, as claimed in dependent claims 16 and 17.
  • However, US 5,524,169 does not appear to teach using the location information to control the speech output unit, nor does it disclose using the semantic recognition result to control the signal pre-processor. Therefore, it does not anticipate the complete system defined in independent claims 1, 20, 22, or 23.

3. US 7,016,837 B2

• Full Citation: US Patent No. 7,016,837 B2, "Voice recognition system," assigned to Pioneer Corporation.
• Issue Date: March 21, 2006
• Brief Description: This patent describes a system that adapts to both the environment and the user's speaking style. It analyzes non-semantic vocal characteristics like speaking speed and volume. This analysis is used to select the most appropriate acoustic model from a library, thereby improving recognition when a user's speaking style changes.
• Potential Anticipation of Claims:
  • This reference teaches the analysis of non-semantic characteristics like volume, as specified in dependent claim 10 of patent 8,306,815.
  • It uses this analysis to control the speech recognition unit by selecting models, which is the subject of dependent claims 16 and 17.
  • The patent does not appear to disclose the key control loops of the independent claims: using the non-semantic analysis to control the system's output and using the recognized words to control the system's input pre-processing. It therefore fails to anticipate independent claims 1, 20, 22, or 23.

4. US 2003/0061037 A1

• Full Citation: US Patent Application Publication No. 2003/0061037 A1, "Method and apparatus for identifying noise environments from noisy signals."
• Publication Date: March 27, 2003
• Brief Description: This application discloses a system that identifies the specific type of background noise in a speech signal (e.g., car noise, babble). It then uses this noise identification to select an optimal model for speech recognition or noise compensation, with the goal of improving recognition accuracy.
• Potential Anticipation of Claims:
  • This reference provides a clear example of generating an "analysis signal" based on a non-semantic characteristic (the noise environment), as described in dependent claim 4 of patent 8,306,815.
  • It further uses this analysis to adapt the recognition process, which is relevant to dependent claims 16 and 17.
  • As with the other references, it does not describe the specific dual-control architecture required by the independent claims. It lacks the teaching of using the noise analysis to control the speech output unit and using the recognized words to control the signal pre-processor. Thus, it does not anticipate claims 1, 20, 22, or 23.