calib-targets

Mesh-rectified grid

Fast, robust calibration target detection in Rust: chessboard, ChArUco, ArUco/AprilTag dictionaries, and marker boards.

Highlights

Shared TargetDetection output across detectors for consistent downstream processing.
End-to-end helpers (calib_targets::detect) that run ChESS corner detection for you (feature image, enabled by default).
Low-level detector crates are re-exported when you need custom pipelines.

Quickstart (chessboard)

cargo add calib-targets image

use calib_targets::detect::{self, ChessConfig};
use calib_targets::ChessboardParams;
use image::ImageReader;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let img = ImageReader::open("board.png")?.decode()?.to_luma8();
    let chess_cfg: ChessConfig = detect::default_chess_config();
    let params = ChessboardParams::default();

    let result = detect::detect_chessboard(&img, &chess_cfg, params);
    println!("detected: {}", result.is_some());
    Ok(())
}

When you need to tune the ChESS stage, use the workspace-owned config types from calib_targets::detect instead of depending on chess-corners directly.

What you get back

All detectors produce a TargetDetection (returned directly for chessboards and embedded in higher-level result structs elsewhere). Each LabeledCorner includes pixel position, optional grid coordinates, optional logical id, optional target-space position, and a detector-specific score.

Supported targets

Chessboard: detect::detect_chessboard or chessboard::ChessboardDetector.
ChArUco: detect::detect_charuco or charuco::CharucoDetector.
Marker boards: detect::detect_marker_board or marker::MarkerBoardDetector.
ArUco/AprilTag dictionaries and decoding via aruco.
Printable targets: printable::render_target_bundle / printable::write_target_bundle.

Features

image (default): enables calib_targets::detect helpers that use image::GrayImage and chess-corners.
tracing: enables tracing output across the workspace crates.

Examples (repo)

cargo run -p calib-targets --example detect_chessboard -- path/to/image.png
cargo run -p calib-targets --example detect_charuco -- path/to/image.png
cargo run -p calib-targets --example detect_markerboard -- path/to/image.png
cargo run -p calib-targets --example generate_printable -- testdata/printable/charuco_a4.json tmpdata/printable/charuco_a4

Printable targets

The facade re-exports the dedicated published calib-targets-print crate as calib_targets::printable. PrintableTargetDocument is the canonical JSON-backed input, and write_target_bundle writes <stem>.json, <stem>.svg, and <stem>.png in one call.

For the full printable-target workflow, including the canonical JSON example, CLI/Python entry points, and print-scale validation guidance, see the printable-target guide. The repo-local calib-targets-cli binary mentioned in the workspace docs is not published on crates.io.

Python bindings

Python bindings are provided via crates/calib-targets-py (module name calib_targets). See crates/calib-targets-py/README.md for setup.

pip install maturin
maturin develop
python crates/calib-targets-py/examples/detect_charuco.py path/to/image.png

Notes:

Python config accepts typed params classes only.
detect_charuco requires params and the board lives in params.board.
target_position is populated only when a board layout includes a valid cell size and alignment succeeds (for marker boards, set params.layout.cell_size).

Crate map

calib_targets::core – core types and homographies.
calib_targets::chessboard – chessboard detection.
calib_targets::aruco – ArUco/AprilTag dictionaries and decoding.
calib_targets::charuco – ChArUco alignment and IDs.
calib_targets::marker – checkerboard + circle marker boards.
calib_targets::printable – printable target generation.

calib-targets 0.5.2