| | 1 | import sounddevice |
| | 2 | import numpy |
| | 3 | |
| | 4 | |
| | 5 | class Noise(): |
| | 6 | def __init__(self, |
| | 7 | sample_rate=16000, |
| | 8 | duration=0.5): |
| | 9 | """Noise measurement. |
| | 10 | |
| | 11 | :param sample_rate: Sample rate in Hz |
| | 12 | :param duraton: Duration, in seconds, of noise sample capture |
| | 13 | |
| | 14 | """ |
| | 15 | |
| | 16 | self.duration = duration |
| | 17 | self.sample_rate = sample_rate |
| | 18 | |
| | 19 | def get_amplitudes_at_frequency_ranges(self, ranges): |
| | 20 | """Return the mean amplitude of frequencies in the given ranges. |
| | 21 | |
| | 22 | :param ranges: List of ranges including a start and end range |
| | 23 | |
| | 24 | """ |
| | 25 | recording = self._record() |
| | 26 | magnitude = numpy.abs(numpy.fft.rfft(recording[:, 0], n=self.sample_rate)) |
| | 27 | result = [] |
| | 28 | for r in ranges: |
| | 29 | start, end = r |
| | 30 | result.append(numpy.mean(magnitude[start:end])) |
| | 31 | return result |
| | 32 | |
| | 33 | def get_amplitude_at_frequency_range(self, start, end): |
| | 34 | """Return the mean amplitude of frequencies in the specified range. |
| | 35 | |
| | 36 | :param start: Start frequency (in Hz) |
| | 37 | :param end: End frequency (in Hz) |
| | 38 | |
| | 39 | """ |
| | 40 | n = self.sample_rate // 2 |
| | 41 | if start > n or end > n: |
| | 42 | raise ValueError("Maxmimum frequency is {}".format(n)) |
| | 43 | |
| | 44 | recording = self._record() |
| | 45 | magnitude = numpy.abs(numpy.fft.rfft(recording[:, 0], n=self.sample_rate)) |
| | 46 | return numpy.mean(magnitude[start:end]) |
| | 47 | |
| | 48 | def get_noise_profile(self, |
| | 49 | noise_floor=100, |
| | 50 | low=0.12, |
| | 51 | mid=0.36, |
| | 52 | high=None): |
| | 53 | """Returns a noise charateristic profile. |
| | 54 | |
| | 55 | Bins all frequencies into 3 weighted groups expressed as a percentage of the total frequency range. |
| | 56 | |
| | 57 | :param noise_floor: "High-pass" frequency, exclude frequencies below this value |
| | 58 | :param low: Percentage of frequency ranges to count in the low bin (as a float, 0.5 = 50%) |
| | 59 | :param mid: Percentage of frequency ranges to count in the mid bin (as a float, 0.5 = 50%) |
| | 60 | :param high: Optional percentage for high bin, effectively creates a "Low-pass" if total percentage is less than 100% |
| | 61 | |
| | 62 | """ |
| | 63 | |
| | 64 | if high is None: |
| | 65 | high = 1.0 - low - mid |
| | 66 | |
| | 67 | recording = self._record() |
| | 68 | magnitude = numpy.abs(numpy.fft.rfft(recording[:, 0], n=self.sample_rate)) |
| | 69 | |
| | 70 | sample_count = (self.sample_rate // 2) - noise_floor |
| | 71 | |
| | 72 | mid_start = noise_floor + int(sample_count * low) |
| | 73 | high_start = mid_start + int(sample_count * mid) |
| | 74 | noise_ceiling = high_start + int(sample_count * high) |
| | 75 | |
| | 76 | amp_low = numpy.mean(magnitude[self.noise_floor:mid_start]) |
| | 77 | amp_mid = numpy.mean(magnitude[mid_start:high_start]) |
| | 78 | amp_high = numpy.mean(magnitude[high_start:noise_ceiling]) |
| | 79 | amp_total = (low + mid + high) / 3.0 |
| | 80 | |
| | 81 | return amp_low, amp_mid, amp_high, amp_total |
| | 82 | |
| | 83 | def _record(self): |
| | 84 | return sounddevice.rec( |
| | 85 | int(self.duration * self.sample_rate), |
| | 86 | samplerate=self.sample_rate, |
| | 87 | blocking=True, |
| | 88 | channels=1, |
| | 89 | dtype='float64' |
| | 90 | ) |
projects / EVA-2020-02-2.git / blame_incremental