Crate opencv_ros_camera for the Rust language

Geometric models of OpenCV/ROS cameras for photogrammetry

About

This crate provides a geometric model of a camera compatible with OpenCV as used by ROS (the Robot Operating System). The crate is in pure Rust, can be compiled in no_std mode, implements the IntrinsicsParameters trait from the cam-geom and provides support to read and write camera models in various formats.

In greater detail:

• Compatible with camera calibrations made by the ROS camera_calibration package, including monocular and stereo calibrations. Despite this compatibility, does not depend on ROS or OpenCV. (Furthermore, there is also no dependency on the excellent rosrust crate).
• Can be compiled without the Rust standard library or allocator to support embedded applications.
• The RosOpenCvIntrinsics type implements the IntrinsicsParameters trait from the cam-geom crate. Thus, a cam_geom::Camera can be created to handle intrinsic parameters using RosOpenCvIntrinsics and camera pose handled by the ExtrinsicParameters struct from cam-geom. (See the example below.)
• When compiled with the serde-serialize feature, read camera calibrations saved by the ROS camera_calibration/cameracalibrator.py node in ~/.ros/camera_info/camera_name.yaml with from_ros_yaml.
• When compiled with the serde-serialize feature, read and write the RosOpenCvIntrinsics struct using serde.

Example - read a ROS YAML file and create a cam_geom::Camera from it.

Let's say we have YAML file saved by the ROS camera_calibration/cameracalibrator.py node. How can we create a cam_geom::Camera from this?

use nalgebra::{Matrix2x3, Unit, Vector3};

// Here we have the YAML file contents hardcoded in a string. Ordinarily, you
// would read this from a file such as `~/.ros/camera_info/camera_name.yaml`, but
// for this example, it is hardcoded here.
let yaml_buf = b"image_width: 659
image_height: 494
camera_name: Basler_21029382
camera_matrix:
  rows: 3
  cols: 3
  data: [516.385667640757, 0, 339.167079537312, 0, 516.125799367807, 227.37993524141, 0, 0, 1]
distortion_model: plumb_bob
distortion_coefficients:
  rows: 1
  cols: 5
  data: [-0.331416226762003, 0.143584747015566, 0.00314558656668844, -0.00393597842852019, 0]
rectification_matrix:
  rows: 3
  cols: 3
  data: [1, 0, 0, 0, 1, 0, 0, 0, 1]
projection_matrix:
  rows: 3
  cols: 4
  data: [444.369750976562, 0, 337.107817516087, 0, 0, 474.186859130859, 225.062742824321, 0, 0, 0, 1, 0]";

// The ROS YAML file does not contain the pose (no extrinsic parameters). Here we
// specify them directly. The camera is at (10,0,0), looing at (0,0,0), with up (0,0,1).
let camcenter = Vector3::new(10.0, 0.0, 0.0);
let lookat = Vector3::new(0.0, 0.0, 0.0);
let up = Unit::new_normalize(Vector3::new(0.0, 0.0, 1.0));
let pose = cam_geom::ExtrinsicParameters::from_view(&camcenter, &lookat, &up);

// We need the `serde-serialize` feature for the `from_ros_yaml` function.
#[cfg(feature = "serde-serialize")]
{
    let from_ros = opencv_ros_camera::from_ros_yaml(&yaml_buf[..]).unwrap();

    // Finally, create camera from intrinsic and extrinsic parameters.
    let camera = cam_geom::Camera::new(from_ros.intrinsics, pose);
}

testing

Test no_std compilation with:

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

Run unit tests with:

cargo test
cargo test --features serde-serialize

serde support requires std.

re-render README.md

cargo install cargo-readme
cargo readme > README.md

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Code of conduct

Anyone who interacts with this software in any space, including but not limited to this GitHub repository, must follow our code of conduct.

License

Licensed under either of these:

• Apache License, Version 2.0, (LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT)