Camera Intrinsics

CameraIntrinsics

class perception.CameraIntrinsics(frame, fx, fy=None, cx=0.0, cy=0.0, skew=0.0, height=None, width=None)

Bases: object

A set of intrinsic parameters for a camera. This class is used to project and deproject points.

__init__(frame, fx, fy=None, cx=0.0, cy=0.0, skew=0.0, height=None, width=None)

Initialize a CameraIntrinsics model.

Parameters:
  • frame (str) – The frame of reference for the point cloud.
  • fx (float) – The x-axis focal length of the camera in pixels.
  • fy (float) – The y-axis focal length of the camera in pixels.
  • cx (float) – The x-axis optical center of the camera in pixels.
  • cy (float) – The y-axis optical center of the camera in pixels.
  • skew (float) – The skew of the camera in pixels.
  • height (float) – The height of the camera image in pixels.
  • width (float) – The width of the camera image in pixels
frame

str – The frame of reference for the point cloud.

fx

float – The x-axis focal length of the camera in pixels.

fy

float – The y-axis focal length of the camera in pixels.

cx

float – The x-axis optical center of the camera in pixels.

cy

float – The y-axis optical center of the camera in pixels.

skew

float – The skew of the camera in pixels.

height

float – The height of the camera image in pixels.

width

float – The width of the camera image in pixels

proj_matrix

numpy.ndarray – The 3x3 projection matrix for this camera.

K

numpy.ndarray – The 3x3 projection matrix for this camera.

crop(height, width, crop_ci, crop_cj)

Convert to new camera intrinsics for crop of image from original camera.

Parameters:
  • height (int) – height of crop window
  • width (int) – width of crop window
  • crop_ci (int) – row of crop window center
  • crop_cj (int) – col of crop window center
Returns:

camera intrinsics for cropped window
Return type:

CameraIntrinsics
resize(scale)

Convert to new camera intrinsics with parameters for resized image.

Parameters:scale (float) – the amount to rescale the intrinsics
Returns:camera intrinsics for resized image
Return type:CameraIntrinsics
project(point_cloud, round_px=True)

Projects a point cloud onto the camera image plane.

Parameters:
  • point_cloud (autolab_core.PointCloud or autolab_core.Point) – A PointCloud or Point to project onto the camera image plane.
  • round_px (bool) – If True, projections are rounded to the nearest pixel.
Returns:

A corresponding set of image coordinates representing the given PointCloud’s projections onto the camera image plane. If the input was a single Point, returns a 2D Point in the camera plane.
Return type:

autolab_core.ImageCoords or autolab_core.Point
Raises:

ValueError – If the input is not a PointCloud or Point in the same reference frame as the camera.
project_to_image(point_cloud, round_px=True)

Projects a point cloud onto the camera image plane and creates a depth image. Zero depth means no point projected into the camera at that pixel location (i.e. infinite depth).

Parameters:
  • point_cloud (autolab_core.PointCloud or autolab_core.Point) – A PointCloud or Point to project onto the camera image plane.
  • round_px (bool) – If True, projections are rounded to the nearest pixel.
Returns:

A DepthImage generated from projecting the point cloud into the camera.
Return type:

DepthImage
Raises:

ValueError – If the input is not a PointCloud or Point in the same reference frame as the camera.
deproject(depth_image)

Deprojects a DepthImage into a PointCloud.

Parameters:depth_image (DepthImage) – The 2D depth image to projet into a point cloud.
Returns:A 3D point cloud created from the depth image.
Return type:autolab_core.PointCloud
Raises:ValueError – If depth_image is not a valid DepthImage in the same reference frame as the camera.
deproject_to_image(depth_image)

Deprojects a DepthImage into a PointCloudImage.

Parameters:depth_image (DepthImage) – The 2D depth image to projet into a point cloud.
Returns:A point cloud image created from the depth image.
Return type:PointCloudImage
Raises:ValueError – If depth_image is not a valid DepthImage in the same reference frame as the camera.
deproject_pixel(depth, pixel)

Deprojects a single pixel with a given depth into a 3D point.

Parameters:
  • depth (float) – The depth value at the given pixel location.
  • pixel (autolab_core.Point) – A 2D point representing the pixel’s location in the camera image.
Returns:

The projected 3D point.
Return type:

autolab_core.Point
Raises:

ValueError – If pixel is not a valid 2D Point in the same reference frame as the camera.
save(filename)

Save the CameraIntrinsics object to a .intr file.

Parameters:filename (str) – The .intr file to save the object to.
Raises:ValueError – If filename does not have the .intr extension.
static load(filename)

Load a CameraIntrinsics object from a file.

Parameters:filename (str) – The .intr file to load the object from.
Returns:The CameraIntrinsics object loaded from the file.
Return type:CameraIntrinsics
Raises:ValueError – If filename does not have the .intr extension.