Create unit tests for Fluctuation Strength implementation

fchirono / MoSQITo

MoSQITo is a unified and modular development framework of key sound quality metrics favoring reproducible science and efficient shared scripting among engineers, teachers and researchers community.

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Create unit tests for Fluctuation Strength implementation #1

Closed fchirono closed 9 months ago

fchirono commented 10 months ago

[x] Create a "test_fluctuation_strength.py" file with the unit tests for the Fluctuation Strength implementation
[x] Add it to the "tests/sq_metrics/fluctuation_strength" folder.
[x] Create unit tests based on literature (Sottek's papers, Fastl & Zwicker, ECMA-418-2)

Current assumptions in the code that need confirmation:

[x] Fastl & Zwicker define signal amplitude (e.g. 60 dB SPL) of modulated signals before applying modulation
[x] Fastl & Zwicker define AM modulation depth in dB as the modulation depth in percentage (e.g. 100%), calculated to dB - so 20*log10(100) = 40 dB modulation depth

fchirono commented 10 months ago

Suggestion for test/validation: compare Fluctuation Strength calculation with modeled curves for synthetic sounds (amplitude- and frequency-modulated pure tones). Sottek et al [1] has analytical expressions for:

The effect of modulation rate on the Fluctuation Strength of an amplitude-modulated (AM) 1 kHz tone at 70 dB and 40 dB modulation depth [Eq. 1];
The effect of modulation rate on the Fluctuation Strength of a frequency-modulated (FM) 1.5 kHz tone at 70 dB and 700 Hz frequency deviation [Eq. 2];
The effect of sound pressure level in dB on the Fluctuation Strength of AM and FM signals [Eq. 3];
The effect of frequency deviation and carrier frequency on the Fluctuation Strength of FM signals [Eq. 4].

[1] R. Sottek et al, "Perception of Fluctuating Sounds", DAGA 2021 - https://pub.dega-akustik.de/DAGA_2021/data/articles/000087.pdf

fchirono commented 10 months ago

The equations from Sottek et al (DAGA 2021) describing the perceived Fluctuation Strength to synthetic, stationary AM/FM sounds are now implemented in tests/sq_metrics/fluctuation_strength/test_fluctuation_strength.py. These could be used to validate the Fluctuation Strength function, such as checking for max. 20% deviation from these metrics.

fchirono commented 9 months ago

Added unit tests for Fluctuation Strength implementation: they generate the required test signals to compare with the Figures 1, 2, 3a, 3b, 5 and 6 in Sottek et al (DAGA 2021), and assert that all FS values are within 20% of the expressions given in the same paper.

At the moment, the dummy implementation of fluctuation_strength.py always returns 1, so all tests will always fail.

fchirono commented 9 months ago

Batch of unit tests created successfully, in test_fluctuation_strength.py. The auxiliary variable force_pass inside this function lets the test progress and creates the figures even when the actual test calculation fails, which helps to see the results and run all the tests.

More tests can be added in the future, but this is probably good enough for now.