Rhasspy Raven Wakeword System

Wakeword detector based on the Snips Personal Wake Word Detector.

The underlying implementation of Raven heavily borrows from node-personal-wakeword by mathquis.

Dependencies

• Python 3.7
• python-speech-features for MFCC computation
• rhasspy-silence for silence detection

Installation

$ git clone https://github.com/rhasspy/rhasspy-wake-raven.git
$ cd rhasspy-wake-raven
$ ./configure
$ make
$ make install

Recording Templates

Record at least 3 WAV templates with your wake word:

$ arecord -r 16000 -f S16_LE -c 1 -t raw | \
    bin/rhasspy-wake-raven --record 'my-wake-word-{n:02d}.wav' my-wake-word/

Follow the prompts and speak your wake word. When you've recorded at least 3 examples, hit CTRL+C to exit. Your WAV templates will have silence automatically trimmed, and will be saved in the directory my-wake-word/.

If you want to manually record WAV templates, trim silence off the front and back and make sure to export them as 16-bit 16Khz mono WAV files.

Running

After recording your WAV templates in a directory, run:

$ arecord -r 16000 -f S16_LE -c 1 -t raw | \
    bin/rhasspy-wake-raven <WAV_DIR> ...

where <WAV_DIR> contains the WAV templates. You may also specify individual WAV files.

Add --debug to the command line to get more information about the underlying computation on each audio frame.

Example

Using the example files for "okay rhasspy":

$ arecord -r 16000 -f S16_LE -c 1 -t raw | \
    bin/rhasspy-wake-raven etc/okay-rhasspy/

This requires at least 1 of the 3 WAV templates to match before output like this is printed:

{"keyword": "etc/okay-rhasspy/okay-rhasspy-00.wav", "detect_seconds": 2.7488508224487305, "detect_timestamp": 1594996988.638912, "raven": {"probability": 0.45637207995699963, "distance": 0.25849045215799454, "probability_threshold": 0.5, "distance_threshold": 0.22, "tick": 1, "matches": 2}}

Use --minimum-matches to change how many templates must match for a detection to occur. Adjust the sensitivity with --probability-threshold which sets the lower bound of the detection probability (default is 0.5).

Output

Raven outputs a line of JSON when the wake word is detected. Fields are:

• keyword - path to WAV file template
• detect_seconds - seconds after start of program when detection occurred
• detect_timestamp - timestamp when detection occurred (using time.time())
• raven
  • probability - detection probability
  • probability_threshold - range of probabilities for detection
  • distance - normalized dynamic time warping distance
  • distance_threshold - distance threshold used for comparison
  • matches - number of WAV templates that matched
  • tick - monotonic counter incremented for each detection

Testing

You can test how well Raven works on a set of sample WAV files:

$ PATH=$PWD/bin:$PATH test-raven.py --test-directory /path/to/samples/ /path/to/templates/

This will run up to 10 parallel instances of Raven (change with --test-workers) and output a JSON report with detection information and summary statistics like:

{
  "positive": [...],
  "negative": [...],
  "summary": {
    "true_positives": 14,
    "false_positives": 0,
    "true_negatives": 40,
    "false_negatives": 7,
    "precision": 1.0,
    "recall": 0.6666666666666666,
    "f1_score": 0.8
}

Any additional command-line arguments are passed to Raven (e.g., --minimum-matches).

Command-Line Interface

usage: rhasspy-wake-raven [-h]
                          [--probability-threshold PROBABILITY_THRESHOLD PROBABILITY_THRESHOLD]
                          [--distance-threshold DISTANCE_THRESHOLD]
                          [--minimum-matches MINIMUM_MATCHES]
                          [--refractory-seconds REFRACTORY_SECONDS]
                          [--print-all-matches]
                          [--window-shift-seconds WINDOW_SHIFT_SECONDS]
                          [--dtw-window-size DTW_WINDOW_SIZE]
                          [--vad-sensitivity {1,2,3}]
                          [--current-threshold CURRENT_THRESHOLD]
                          [--max-energy MAX_ENERGY]
                          [--max-current-ratio-threshold MAX_CURRENT_RATIO_THRESHOLD]
                          [--silence-method {vad_only,ratio_only,current_only,vad_and_ratio,vad_and_current,all}]
                          [--average-templates] [--debug]
                          templates [templates ...]

positional arguments:
  templates             Path to WAV file templates

optional arguments:
  -h, --help            show this help message and exit
  --probability-threshold PROBABILITY_THRESHOLD PROBABILITY_THRESHOLD
                        Probability range where detection occurs (default:
                        (0.45, 0.55))
  --distance-threshold DISTANCE_THRESHOLD
                        Normalized dynamic time warping distance threshold for
                        template matching (default: 0.22)
  --minimum-matches MINIMUM_MATCHES
                        Number of templates that must match to produce output
                        (default: 1)
  --refractory-seconds REFRACTORY_SECONDS
                        Seconds before wake word can be activated again
                        (default: 2)
  --print-all-matches   Print JSON for all matching templates instead of just
                        the first one
  --window-shift-seconds WINDOW_SHIFT_SECONDS
                        Seconds to shift sliding time window on audio buffer
                        (default: 0.05)
  --dtw-window-size DTW_WINDOW_SIZE
                        Size of band around slanted diagonal during dynamic
                        time warping calculation (default: 5)
  --vad-sensitivity {1,2,3}
                        Webrtcvad VAD sensitivity (1-3)
  --current-threshold CURRENT_THRESHOLD
                        Debiased energy threshold of current audio frame
  --max-energy MAX_ENERGY
                        Fixed maximum energy for ratio calculation (default:
                        observed)
  --max-current-ratio-threshold MAX_CURRENT_RATIO_THRESHOLD
                        Threshold of ratio between max energy and current
                        audio frame
  --silence-method {vad_only,ratio_only,current_only,vad_and_ratio,vad_and_current,all}
                        Method for detecting silence
  --average-templates   Average wakeword templates together to reduce number
                        of calculations
  --debug               Print DEBUG messages to the console