navlie.lib.camera.PinholeCamera¶

class navlie.lib.camera.PinholeCamera(fu: float, fv: float, cu: float, cv: float, image_width: int, image_height: int, sigma: float, T_bc: PoseMatrix | None = None, camera_id: Any | None = None)¶

Bases: object

Class for a pinhole camera model.

This class contains utilities for generating measurements and predicting measurements, and converting pixel coordinates to normalized image coordinates using the camera intrinsic parameters.

Instantiate a PinholeCamera

Parameters:

fu (float) – Focal length, horizontal pixels.
fv (float) – Focal length, vertical pixels.
cu (float) – Optical axis intersection, horizontal pixels.
cv (float) – Optical axis intersection, vertical pixels.
image_width (int) – Image Plane width in pixels.
image_height (int) – Image plane height in pixels.
sigma (float) – Camera noise, in pixels.
T_bc (PoseMatrix, optional) – Transformation between the body frame and the camera frame, by default None. If None, transformation will be set to identity.
camera_id (Any, optional) – Identifier for this camera, by default None

static get_cam_to_enu() → ndarray¶: Returns a DCM that relates the “ENU frame to the camera frame, where the camera z-axis points forward. Camera frame: x right, y down, z forward ENU frame: x forward, y left, z up

property intrinsics: ndarray¶: Returns the intrinsic matrix K.

property sigma_normalized_image_coords: ndarray¶

property R_normalized_image_coords: ndarray¶

copy() → PinholeCamera¶: Returns a copy of the camera model.

is_measurement_valid(uv: ndarray) → bool¶

Checks if a measurement is valid.

A valid measurement should be positive and within the image plane.

Parameters:: uv (np.ndarray) – Measurement to check.
Returns:: Is valid.
Return type:: bool

is_landmark_in_front_of_cam(pose: SE3State, r_pw_a: ndarray) → bool¶: Checks if a given landmark is in front of the camera.

evaluate(pose: SE3State, r_pw_a: ndarray) → ndarray¶

Predicts a noise-free measurement.

Parameters:

X (IMUState) – IMU state to generate measurement from
r_pw_a (np.ndarray) – 3D landmark position, resolved in the world frame.

Returns:

noise-free pixel measurement

Return type:

np.ndarray

resolve_landmark_in_cam_frame(pose: SE3State, r_pw_a: ndarray)¶: Resolves a landmark with position r_pw_a in the camera frame.

project(r_pc_c: ndarray) → ndarray¶

Pinhole projection model.

Parameters:: r_pc_c (np.ndarray) – Landmark relative to camera, resolved in camera frame.
Returns:: (u, v) pixel coordinates.
Return type:: np.ndarray

to_normalized_coords(uv: ndarray) → ndarray¶

Converts (u, v) pixel coordinates to normalized image coordinates.

Parameters:: uv (np.ndarray) – Pixel coordinates
Returns:: Normalized image coordinates, computed using intrinsics.
Return type:: np.ndarray

to_pixel_coors(meas: ndarray) → ndarray¶

navlie.lib.camera

navlie.lib.camera.PoseMatrix