[−][src]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
Currently, this crate does not build without std, but this is a bug that will be fixed.
Example
use nalgebra::{Dynamic, MatrixMN, U2, U3, U4, U8}; // homogeneous 3D coords let x3dh_data: Vec<f64> = vec![ -1., -2., -3., 1.0, 0., 0., 0., 1.0, 1., 2., 3., 1.0, 1.1, 2.2, 3.3, 1.0, 4., 5., 6., 1.0, 4.4, 5.5, 6.6, 1.0, 7., 8., 9., 1.0, 7.7, 8.8, 9.9, 1.0, ]; let n_points = x3dh_data.len() / 4; let x3dh = MatrixMN::<_, Dynamic, U4>::from_row_slice(&x3dh_data); // example camera calibration matrix #[rustfmt::skip] let pmat_data: Vec<f64> = vec![ 100.0, 0.0, 0.1, 320.0, 0.0, 100.0, 0.2, 240.0, 0.0, 0.0, 0.0, 1.0, ]; let pmat = MatrixMN::<_, U3, U4>::from_row_slice(&pmat_data); // compute 2d coordinates of camera projection let x2dh = pmat * x3dh.transpose(); // convert 2D homogeneous coords into normal 2D coords let mut data = Vec::with_capacity(2 * n_points); for i in 0..n_points { let r = x2dh[(0, i)]; let s = x2dh[(1, i)]; let t = x2dh[(2, i)]; data.push(r / t); data.push(s / t); } let x2d_expected = MatrixMN::<_, Dynamic, U2>::from_row_slice(&data); // convert homogeneous 3D coords into normal 3D coords let x3d = x3dh.fixed_columns::<U3>(0).into_owned(); // perform DLT let dlt_results = dlt::dlt(&x3d, &x2d_expected, 1e-10).unwrap(); // compute 2d coordinates of camera projection with DLT-found matrix let x2dh2 = dlt_results * x3dh.transpose(); // convert 2D homogeneous coords into normal 2D coords let mut data = Vec::with_capacity(2 * n_points); for i in 0..n_points { let r = x2dh2[(0, i)]; let s = x2dh2[(1, i)]; let t = x2dh2[(2, i)]; data.push(r / t); data.push(s / t); } let x2d_actual = MatrixMN::<_, Dynamic, U2>::from_row_slice(&data); assert_eq!(x2d_expected.nrows(), x2d_actual.nrows()); assert_eq!(x2d_expected.ncols(), x2d_actual.ncols()); for i in 0..x2d_expected.nrows() { for j in 0..x2d_expected.ncols() { approx::assert_relative_eq!( x2d_expected[(i, j)], x2d_actual[(i, j)], epsilon = 1e-10 ); } }
See also
You may also be interested in:
cam-geom
- Rust crate with 3D camera models which can use the calibration data from DLT.
Structs
CorrespondingPoint | A point with a view in image (2D) and world (3D). |
Functions
dlt | Direct Linear Transformation (DLT) to find a camera calibration matrix. |
dlt_corresponding | Convenience wrapper around the |