ABOUT PARROT

Parrot Algorithms

Since 1994 Parrot engineers have built state-of-the-art acoustic software to offer superior sound quality in the most demanding of settings, with a focus on high-noise car environments.

Noise Reduction

Characteristics

  • Treatment on spectral domain (128 frequency bands).
  • Uses statistical properties of speech.
  • Continuous noise estimation.
  • Well-coupled with our AEC.

Performance

  • No musical noise (colourless residual noise).
  • Low speech quality degradation.
  • Robust to non stationary noise.
  • Noise level reduced by more than 10 dB (up to 20dB).
  • Initial convergence masked by AGC.
  • Fast convergence (~60ms).

Parrot Beamforming®

  • The newest Parrot hands free car kits incorporates the very latest “Parrot Beamforming®” signal processing technology by means of a pair of twin microphones. As a result, the kit picks up the driver's voice more clearly, while effectively reducing surrounding noise.

 

Reliable Voice Recognition

Functions

  • Isolated words (name dialing).
  • Keyword Spotting (full vocal interface).
  • Up to 500 voice patterns.
  • Rejection of « out of vocabulary » names.
  • No language dependency.

Main Characteristics

  • Improved MFCC-based feature extraction.
  • DTW matching.
  • Noise robustness.
  • Noise adaptability.
  • Speech/non-speech detection.

Performance

  • High recognition rates.
  • Algorithms optimized with home-made database, specially difficult for ASR.

Design on DSP

  • Hand-written assembler code.
  • DTW hardware accelerator (7 times faster).
  • Real-time processing (negligible response time after a recognition).
  • Noise adaptability.
  • Available on TI and Oak DSPs.

Acoustic Echo Cancellation

Characteristics

  • Two layers: Variable Step Size LMS & Automatic Gain Control.
  • Acoustic filter length : 256 samples (32 ms).
  • Low complexity : no double talk detection, only one mode.

Performance

  • Mean ERLE : 40 dB (up to 50 dB).
  • Robust to double-talk : Full-duplex canceller.
  • Fast convergence (31 dB/s).
  • Noise adaptability.
  • Robust to noise and acoustic condition variations.