calculatePatternConfidence()

float fl::audio::detector::Backbeat::calculatePatternConfidence ( const fft::Bins & fft )

private

Definition at line 394 of file backbeat.cpp.hpp.

                                                             {
    // Calculate spectral correlation between current spectrum and learned profile
    // Returns 0-1 indicating how well current spectrum matches typical backbeat
 
    // If profile is not yet learned, return neutral confidence
    bool profileLearned = false;
    for (size i = 0; i < mBackbeatSpectralProfile.size(); i++) {
        if (mBackbeatSpectralProfile[i] > 1e-6f) {
            profileLearned = true;
            break;
        }
    }
 
    if (!profileLearned) {
        return 0.5f;  // Neutral confidence
    }
 
    // Calculate normalized correlation
    size compareSize = fl::min(mBackbeatSpectralProfile.size(), fft.raw().size());
 
    float dotProduct = 0.0f;
    float profileMag = 0.0f;
    float currentMag = 0.0f;
 
    for (size i = 0; i < compareSize; i++) {
        dotProduct += mBackbeatSpectralProfile[i] * fft.raw()[i];
        profileMag += mBackbeatSpectralProfile[i] * mBackbeatSpectralProfile[i];
        currentMag += fft.raw()[i] * fft.raw()[i];
    }
 
    // Cosine similarity
    const float epsilon = 1e-6f;
    float denominator = fl::sqrt(profileMag * currentMag);
 
    if (denominator < epsilon) {
        return 0.5f;  // Neutral if magnitudes too small
    }
 
    float correlation = dotProduct / denominator;
 
    // Clamp to 0-1 range
    return fl::clamp(correlation, 0.0f, 1.0f);
}

References fl::clamp(), mBackbeatSpectralProfile, fl::min(), and fl::sqrt().

Referenced by detectBackbeat().

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