Custom Frequency Scale

class osekit.core_api.frequency_scale.Scale(parts: list[ScalePart])

Class that represent a custom frequency scale for plotting spectrograms.

The custom scale is formed from a list of ScaleParts, which assign a frequency range to a range on the scale. Provided ScaleParts should cover the whole scale (from 0% to 100%).

Such Scale can then be passed to the SpectroData.plot() method for the spectrogram to be plotted on a custom frequency scale.

Initialize a Scale object.

classmethod from_dict_value(dict_value: list[list]) → Scale

Deserialize a Scale from a dictionary entry.

get_mapped_indexes(original_scale: list[float]) → list[int]

Return the indexes of the present scale in the original scale.

The indexes are those of the closest value from the mapped values in the original scale.

Parameters

original_scale: list[float]

Original scale from which the mapped scale is computed.

Returns

list[int]

Indexes of the closest value from the mapped values in the original scale.

get_mapped_values(original_scale: list[float]) → list[float]

Return the closest values of the mapped scale from the original scale.

Parameters

original_scale: list[float]

Original scale from which the mapped scale is computed.

Returns

list[float]

Values from the original scale that are the closest to the mapped scale.

map(original_scale_length: int) → list[float]

Map a given scale to the custom scale defined by its ScaleParts.

Parameters

original_scale_length: int

Length of the original frequency scale.

Returns

list[float]

Mapped frequency scale. Each ScalePart from the Scale.parts attribute are concatenated to form the returned scale.

rescale(sx_matrix: ndarray, original_scale: ndarray | list) → ndarray

Rescale the given spectrum matrix according to the present scale.

Parameters

sx_matrix: np.ndarray

Spectrum matrix.

original_scale: np.ndarray

Original frequency axis of the spectrum matrix.

Returns

np.ndarray

Spectrum matrix mapped on the present scale.

to_dict_value() → list[tuple[float, float, float, float, str]]

Serialize a Scale to a dictionary entry.

class osekit.core_api.frequency_scale.ScalePart(p_min: float, p_max: float, f_min: float, f_max: float, scale_type: Literal['lin', 'log'] = 'lin')

Represent a part of the frequency scale of a spectrogram.

p_min: float

Relative position of the bottom of the scale part on the full scale. Must be in the interval [0.0, 1.0], where 0.0 is the bottom of the scale and 1.0 is the top.

p_max: float

Relative position of the top of the scale part on the full scale. Must be in the interval [0.0, 1.0], where 0.0 is the bottom of the scale and 1.0 is the top.

f_min: float

Frequency corresponding to the bottom of the scale part.

f_max: float

Frequency corresponding to the top of the scale part.

scale_type: Literal[“lin”, “log”]

Type of the scale, either linear or logarithmic.

get_frequencies(nb_points: int) → list[int]

Return the frequency points of the present scale part.

get_indexes(scale_length: int) → tuple[int, int]

Return the indexes of the present scale part in the full scale.

get_values(scale_length: int) → list[int]

Return the values of the present scale part.

property scale_lambda: callable

Lambda function used to generate either a linear or logarithmic scale.

to_dict_value() → tuple[float, float, float, float, str]

Serialize a ScalePart to a dictionary entry.