Skip to content

README.md

Latest commit

 

History

History
86 lines (65 loc) · 2.83 KB

README.md

File metadata and controls

86 lines (65 loc) · 2.83 KB
Raw

C++ side

Requires OpenCV 4 (core imgproc calib3d imgcodecs — no highgui) and a C++17 compiler. Tested with OpenCV 4.2 on GCC 9.

The C++ half uses the system OpenCV via CMake's find_package and has nothing to do with uv — that manages the Python side only.

cd cpp
cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build -j

Everything lands in cpp/build/bin/.

On Debian/Ubuntu the dependency is sudo apt install libopencv-dev cmake g++.

Interactive exploration

Live exploration lives in the browser: https://cyhunblr.github.io/learn_camera_intrinsics/. Nothing here opens a window.

Figure renderers

./build/bin/render_2d --out out.png [--preset N] [--chart N] [--alpha A]
./build/bin/render_3d --out out.png [--preset N] [--no-distortion]

They draw the same figures as their Python twins from the same maths. The geometry is identical to the last bit; the pixels are not quite, because OpenCV's built-in Hershey font rasterises slightly differently between major versions, so the HUD text lands a pixel or two apart.

Examples

./build/bin/01_pinhole_projection
./build/bin/02_k_matrix_anatomy    out.png     # figure path is optional
./build/bin/03_distortion_anatomy  out.png
./build/bin/04_resize_crop_roi
./build/bin/05_undistort_and_alpha out.png
./build/bin/06_calibrate_synthetic

Examples 1–5 print the same numbers as their Python twins, to the last decimal. Example 6 uses OpenCV's RNG rather than NumPy's, so the individual figures differ while every conclusion is identical.

Exercises

Implement the ten functions in cpp/exercises/exercises.cpp — the specifications are in exercises.hpp — then:

cmake --build build -j && ./build/bin/check_exercises
./build/bin/check_exercises 3 7           # just those two
./build/bin/check_exercises --solutions   # verify the reference answers
ctest --test-dir build                    # the solutions as a regression test

The library

cpp/include/camintrinsics/ mirrors the Python package function for function.

#include "camintrinsics/intrinsics.hpp"

const ci::Mat33 K = ci::makeK(800, 800, 640, 360);
const ci::Dist  D = ci::makeD(-0.28, 0.09);
const cv::Point2d uv = ci::projectPoint({0.5, 0.2, 4.0}, K, D);
const cv::Vec3d fov = ci::fovDeg(K, 1280, 720);
const ci::Mat33 Khalf = ci::scaleK(K, 0.5, 0.5);
header contents
intrinsics.hpp K/D maths from scratch, verified against OpenCV
scene.hpp 3D primitives as subdivided polylines
renderer.hpp the software renderer, Pose, lookAt, orbitPose
patterns.hpp test charts and the two image warps
plots.hpp the radial-profile and displacement-field plots
presets.hpp the named lens presets and the model summary text
util.hpp ci::fmt and ci::writeImage (honest image writing)