Deltacamera

Camera calibration manipulation and image warping for computer vision.

Deltacamera provides coordinate transformations between world, camera, and image spaces with support for Brown-Conrady and Kannala-Brandt (fisheye) lens distortion models.

Features

• Coordinate transformations between world, camera, and image space with lens distortion

• Camera manipulation with intuitive methods: zoomed, rotated, image_resized, turned_towards

• Accurate distortion inversion using Newton’s method (more accurate than OpenCV)

• Valid region tracking after distortion, extending Leotta et al. to full Brown-Conrady and fisheye models

• Fast image warping with antialiasing, linear RGB interpolation, and map caching

Quick Start

Installation

pip install deltacamera

# Optional: precompile Numba functions (1-2 min, speeds up first use)
python -m deltacamera.precompile

Basic Usage

from deltacamera import Camera

# Create a camera from an intrinsic matrix
cam = Camera(intrinsic_matrix=[[500, 0, 320], [0, 500, 240], [0, 0, 1]])

# Transform 3D world points to 2D image coordinates
image_points = cam.world_to_image([[1, 2, 3], [4, 5, 6]])

# Manipulate the camera (returns a new camera)
cam2 = cam.zoomed(2.0)
cam3 = cam2.rotated(pitch=0.1)

# Remove lens distortion
undistorted_cam = cam.undistorted()

Image Reprojection

Reproject an image from one camera to another (e.g., to undistort or change the virtual viewing direction):

import numpy as np
from deltacamera import Camera, reproject_image

# A camera with Brown-Conrady distortion
cam = Camera(
    intrinsic_matrix=np.array([[500, 0, 320], [0, 500, 240], [0, 0, 1]]),
    distortion_coeffs=[-0.3, 0.1, 0, 0, 0],
    image_shape=(480, 640))

# Undistort: create a pinhole version and warp the image
cam_undist = cam.undistorted()
undistorted_image = reproject_image(image, cam, cam_undist)

# Rotate the virtual camera and reproject
cam_rotated = cam.turned_towards(target_image_point=[100, 200])
cam_rotated = cam_rotated.undistorted()
cam_rotated = cam_rotated.copy(image_shape=(256, 256))
crop = reproject_image(image, cam, cam_rotated)

Point Reprojection

Transform 2D points (e.g., keypoints, bounding box corners) between cameras:

from deltacamera import reproject_image_points

# Reproject keypoints from the original camera to the undistorted one
new_points = reproject_image_points(old_points, cam, cam_undist)