Crate opencv_ros_camera

Expand description

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), looking 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:

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

Structs

Distortion

Specifies distortion using the Brown-Conrady “plumb bob” model.

NamedIntrinsicParameters

A struct with RosOpenCvIntrinsics, camera name and image sensor dimensions.

RosCameraInfo

Camera calibration info as saved by ROS.

RosMatrix

Matrix saved by ROS.

RosOpenCvIntrinsics

A perspective camera model with distortion compatible with OpenCV and ROS.

UndistortedPixels

Undistorted 2D pixel locations

Enums

Error

Possible errors.

TermCriteria

The type defines termination criteria for iterative algorithms.

Traits

CameraExt

Extension trait to add world_to_undistorted_pixel() method.

Functions

from_ros_yaml

Construct NamedIntrinsicParameters from ROS format YAML data.

Type Definitions

Result

Result type