Crate dlt

DLT (direct linear transform) algorithm for camera calibration

This is typically used for calibrating cameras and requires a minimum of 6 corresponding pairs of 2D and 3D locations.

Testing

Unit tests

To run the unit tests:

cargo test

Test for no_std

Since the thumbv7em-none-eabihf target does not have std available, we can build for it to check that our crate does not inadvertently pull in std. The unit tests require std, so cannot be run on a no_std platform. The following will fail if a std dependency is present:

# install target with: "rustup target add thumbv7em-none-eabihf"
cargo build --no-default-features --target thumbv7em-none-eabihf

Example

use dlt::{dlt_corresponding, CorrespondingPoint};

let points: Vec<CorrespondingPoint<f64>> = vec![
    CorrespondingPoint {
        object_point: [-1., -2., -3.],
        image_point: [219.700, 39.400],
    },
    CorrespondingPoint {
        object_point: [0., 0., 0.],
        image_point: [320.000, 240.000],
    },
    CorrespondingPoint {
        object_point: [1., 2., 3.],
        image_point: [420.300, 440.600],
    },
    CorrespondingPoint {
        object_point: [1.1, 2.2, 3.3],
        image_point: [430.330, 460.660],
    },
    CorrespondingPoint {
        object_point: [4., 5., 6.],
        image_point: [720.600, 741.200],
    },
    CorrespondingPoint {
        object_point: [4.4, 5.5, 6.6],
        image_point: [760.660, 791.320],
    },
    CorrespondingPoint {
        object_point: [7., 8., 9.],
        image_point: [1020.900, 1041.800],
    },
    CorrespondingPoint {
        object_point: [7.7, 8.8, 9.9],
        image_point: [1090.990, 1121.980],
    },
];

let pmat = dlt_corresponding(&points, 1e-10).unwrap();
// could now call `cam_geom::Camera::from_perspective_matrix(&pmat)`

See also

You may also be interested in:

• cam-geom - Rust crate with 3D camera models which can use the calibration data from DLT.
• dlt-examples
  • Unpublished crate in the dlt repository which demonstrates usage with cam-geom library.

Structs

CorrespondingPoint

A point with a view in image (2D) and world (3D) coordinates.

Functions

dlt

Direct Linear Transformation (DLT) to find a camera calibration matrix.

dlt_corresponding

Convenience wrapper around the dlt function.