CircularApertureOTFPerturber

class nrtk.impls.perturb_image.pybsm.circular_aperture_otf_perturber.CircularApertureOTFPerturber(sensor: PybsmSensor | None = None, scenario: PybsmScenario | None = None, mtf_wavelengths: Sequence[float] | None = None, mtf_weights: Sequence[float] | None = None, interp: bool = True, box_alignment_mode: str = 'extent')

Applies OTF-based image perturbation using a circular aperture model with sensor and scenario configurations.

The CircularApertureOTFPerturber class uses a circular aperture model to simulate image perturbations, allowing for wavelength-specific and sensor-specific modifications based on the sensor and scenario configurations.

Attributes:: sensor (PybsmSensor | None): The sensor configuration for the perturbation. scenario (PybsmScenario | None): The scenario configuration used for perturbation. mtf_wavelengths (Sequence[float]): Sequence of wavelengths used in MTF calculations. mtf_weights (Sequence[float]): Sequence of weights associated with each wavelength. D (float): Effective aperture diameter. eta (float): Relative linear obscuration. slant_range (float): Line-of-sight distance between platform and target. ifov (float): Instantaneous field of view of the sensor. interp (bool): Specifies whether to use interpolated atmospheric data.

Methods

`from_config`	Instantiates a CircularApertureOTFPerturber from a configuration dictionary.
`get_config`	Returns the current configuration of the CircularApertureOTFPerturber instance.
`get_default_config`	Provides the default configuration for CircularApertureOTFPerturber instances.
`get_impls`	Discover and return a set of classes that implement the calling class.
`get_type_string`	Returns the fully qualified type string of the PerturbImage class or its subclass.
`is_usable`	Checks if the necessary dependencies (pyBSM and OpenCV) are available.
`perturb`	Applies the circular aperture-based perturbation to the provided image.

__init__(sensor: PybsmSensor | None = None, scenario: PybsmScenario | None = None, mtf_wavelengths: Sequence[float] | None = None, mtf_weights: Sequence[float] | None = None, interp: bool = True, box_alignment_mode: str = 'extent') → None

Initializes the CircularApertureOTFPerturber.

Parameters:

sensor – pyBSM sensor object
scenario – pyBSM scenario object
mtf_wavelengths – a numpy array of wavelengths (m)
mtf_weights – a numpy array of weights for each wavelength contribution (arb)
interp – a boolean determining whether load_database_atmosphere is used with or without interpolation
box_alignment_mode –
Mode for how to handle how bounding boxes change. Should be one of the following options:

extent: a new axis-aligned bounding box that encases the transformed misaligned box extant: a new axis-aligned bounding box that is encased inside the transformed misaligned box median: median between extent and extant

Default value is extent

If both sensor and scenario parameters are absent, then default values will be used for their parameters

If none of mtf_wavelengths, mtf_weights, sensor or scenario parameters are provided, the values of mtf_wavelengths and mtf_weights will default to [0.50e-6, 0.66e-6] and [1.0, 1.0] respectively

If sensor and scenario parameters are provided, but not mtf_wavelengths and mtf_weights, the values of mtf_wavelengths and mtf_weights will come from the sensor and scenario objects.

If mtf_wavelengths and mtf_weights are provided by the user, those values will be used in the otf caluclattion

Raises:: ImportError if OpenCV or pyBSM is not found,

install via pip install nrtk[pybsm,graphics] or pip install nrtk[pybsm,headless]. :raises: ValueError if mtf_wavelengths and mtf_weights are not equal length :raises: ValueError if mtf_wavelengths is empty or mtf_weights is empty

classmethod from_config(config_dict: dict, merge_default: bool = True) → Self

Instantiates a CircularApertureOTFPerturber from a configuration dictionary.

Args:: config_dict (dict): Configuration dictionary with initialization parameters. merge_default (bool, optional): Whether to merge with default configuration. Defaults to True.
Returns:: An instance of CircularApertureOTFPerturber.

get_config() → dict[str, Any]

Returns the current configuration of the CircularApertureOTFPerturber instance.

Returns:: dict[str, Any]: Configuration dictionary with current settings.

classmethod get_default_config() → dict[str, Any]

Provides the default configuration for CircularApertureOTFPerturber instances.

Returns:: dict[str, Any]: A dictionary with the default configuration values.

classmethod is_usable() → bool

Checks if the necessary dependencies (pyBSM and OpenCV) are available.

Returns:: bool: True if both pyBSM and OpenCV are available; False otherwise.

perturb(image: np.ndarray, boxes: Iterable[tuple[AxisAlignedBoundingBox, dict[Hashable, float]]] | None = None, additional_params: dict[str, Any] | None = None) → tuple[np.ndarray, Iterable[tuple[AxisAlignedBoundingBox, dict[Hashable, float]]] | None]

Applies the circular aperture-based perturbation to the provided image.

Args:

image (np.ndarray): The image to be perturbed. boxes (Iterable[tuple[AxisAlignedBoundingBox, dict[Hashable, float]]], optional): bounding boxes

for detections in input image

additional_params (dict[str, Any], optional): Additional parameters, including ‘img_gsd’.

Returns:

np.ndarray: The perturbed image. Iterable[tuple[AxisAlignedBoundingBox, dict[Hashable, float]]]: Bounding boxes scaled to perturbed image

shape.

Raises:

ValueError: If ‘img_gsd’ is not provided in additional_params.