nav.sim

render_background_noise(img: ndarray[tuple[Any, ...], dtype[floating[Any]]], noise_level: float, seed: int) → None

Add Gaussian background noise to the image.

Parameters:

• img – Image array to modify in-place.

• noise_level – Standard deviation of Gaussian noise (0-1).

• seed – Random seed for reproducibility.

render_background_stars(img: ndarray[tuple[Any, ...], dtype[floating[Any]]], n_stars: int, seed: int, psf_sigma: float = 0.9, distribution_exponent: float = 2.5) → None

Add random background stars to the image.

Parameters:

• img – Image array to modify in-place (stars are added, not overwritten).

• n_stars – Number of stars to add (0-1000).

• seed – Random seed for reproducibility.

• psf_sigma – PSF sigma value for star rendering (default 0.9).

• distribution_exponent – Power law exponent for intensity distribution (default 2.5). Higher values make dimmer stars more common.

render_bodies(img: ndarray[tuple[Any, ...], dtype[floating[Any]]], bodies_params: list[dict[str, Any]], offset_v: float, offset_u: float, *, seed: int | None = None) → dict[str, Any]

Render bodies over img and return fields by name.

Returns: a dict with keys:

• img: NDArrayFloatType the rendered image

• bodies: dict[str, dict[str, Any]]

• inventory: dict[str, dict[str, float]]

• body_masks: list[NDArrayBoolType]

• order_near_to_far: list[str]

• body_index_map: NDArrayIntType (int32), 1-based index into order_near_to_far or 0 if none

render_combined_model(sim_params: dict[str, Any], *, ignore_offset: bool = False) → tuple[ndarray[tuple[Any, ...], dtype[floating[Any]]], dict[str, Any]]

Render stars then bodies from a full sim_params dict. Returns (img, meta).

ignore_offset = True should be used when rendering the image in the GUI, but not when creating the simulated image to navigate.

Parameters:

• sim_params – The parameters describing the simulated model.

• ignore_offset – Whether to ignore the offset.

Returns:

A tuple containing the image and metadata.

render_stars(img: ndarray[tuple[Any, ...], dtype[floating[Any]]], stars_params: list[dict[str, Any]], offset_v: float, offset_u: float) → tuple[ndarray[tuple[Any, ...], dtype[floating[Any]]], list[MutableStar], list[dict[str, Any]]]

Render stars into img. Returns (img, sim_star_list, star_render_info).

Simulated ring rendering for navigation testing.

This module provides functions to render planetary rings in simulated images for navigation testing. Rings are rendered as circular or elliptical features with anti-aliased edges.

compute_border_atop_simulated(size_v: int, size_u: int, center_v: float, center_u: float, *, a: float, ae: float, long_peri: float, rate_peri: float, epoch: float, time: float) → ndarray[tuple[Any, ...], dtype[bool]]

Compute border_atop mask for simulated ring edge.

This simulates the border_atop backplane function for simulated rings by finding pixels where the distance from center transitions across the edge radius computed from mode 1 parameters.

Parameters:

• size_v – Image height in pixels.

• size_u – Image width in pixels.

• center_v – V coordinate of ring center.

• center_u – U coordinate of ring center.

• a – Semi-major axis in pixels (mode 1 ‘a’ value).

• ae – Eccentricity times semi-major axis in pixels.

• long_peri – Longitude of pericenter in degrees.

• rate_peri – Rate of precession in degrees/day.

• epoch – Epoch time (TDB seconds).

• time – Current time (TDB seconds).

Returns:

Boolean array where True indicates pixels at the edge.

compute_edge_radius_at_angle(angle: float, *, a: float, ae: float, long_peri: float, rate_peri: float, epoch: float, time: float) → float

Compute edge radius at a specific angle using mode 1 parameters.

Parameters:

• angle – Angle in radians from center.

• a – Semi-major axis in pixels.

• ae – Eccentricity times semi-major axis in pixels.

• long_peri – Longitude of pericenter in degrees.

• rate_peri – Rate of precession in degrees/day.

• epoch – Epoch time (TDB seconds).

• time – Current time (TDB seconds).

Returns:

Edge radius in pixels at the given angle.

compute_edge_radius_mode1(center_v: float, center_u: float, pixel_v: float, pixel_u: float, *, a: float, ae: float, long_peri: float, rate_peri: float, epoch: float, time: float) → float

Compute edge radius from mode 1 parameters at a specific pixel.

Parameters:

• center_v – V coordinate of ring center.

• center_u – U coordinate of ring center.

• pixel_v – V coordinate of pixel.

• pixel_u – U coordinate of pixel.

• a – Semi-major axis in pixels.

• ae – Eccentricity times semi-major axis in pixels.

• long_peri – Longitude of pericenter in degrees.

• rate_peri – Rate of precession in degrees/day.

• epoch – Epoch time (TDB seconds).

• time – Current time (TDB seconds).

Returns:

Edge radius in pixels at the given pixel position.

render_ring(img: ndarray[tuple[Any, ...], dtype[floating[Any]]], ring_params: dict[str, Any], offset_v: float, offset_u: float, *, time: float = 0.0, epoch: float = 0.0, shade_solid: bool = False) → None

Render a single ring or gap into the image.

Parameters:

• img – Image array to modify in-place.

• ring_params – Dictionary containing ring parameters: - name: str, ring name - feature_type: str, ‘RINGLET’ or ‘GAP’ - center_v: float, V coordinate of ring center - center_u: float, U coordinate of ring center - shading_distance: float, distance in pixels for edge fading - inner_data: list[dict], mode data for inner edge (mode 1 required) - outer_data: list[dict], mode data for outer edge (mode 1 required)

• offset_v – V offset to apply.

• offset_u – U offset to apply.

• time – Current time in TDB seconds (default 0.0).

• epoch – Epoch time in TDB seconds (default 0.0).

• shade_solid – If True, solid rings (with both edges) are shaded on both sides as if they were two rings (one with inner edge only, one with outer edge only).