Example Visual Odometry Monocular Plane

This example demonstrates how to estimate the camera's ego motion using a single camera and known plane. Since the plane's relative location to the camera is known there is no scale ambiguity, like there is with a more general single camera solution.

Example Code:

• ExampleVisualOdometryMonocularPlane.java

Concepts:

• Plane/Homography

Related Examples:

• Visual Odometry Depth
• Visual Odometry Stereo

Example Code

/**
 * Bare bones example showing how to estimate the camera's ego-motion using a single camera and a known
 * plane. Additional information on the scene can be optionally extracted from the algorithm,
 * if it implements AccessPointTracks3D.
 *
 * @author Peter Abeles
 */
public class ExampleVisualOdometryMonocularPlane {
	public static void main( String[] args ) {
		MediaManager media = DefaultMediaManager.INSTANCE;

		String directory = UtilIO.pathExample("vo/drc/");

		// load camera description and the video sequence
		MonoPlaneParameters calibration = CalibrationIO.load(
				media.openFile(new File(directory, "mono_plane.yaml").getPath()));
		SimpleImageSequence<GrayU8> video = media.openVideo(
				new File(directory, "left.mjpeg").getPath(), ImageType.single(GrayU8.class));

		var config = new ConfigPlanarTrackPnP();

		// specify how the image features are going to be tracked
		config.tracker.typeTracker = ConfigPointTracker.TrackerType.KLT;
		config.tracker.klt.pyramidLevels = ConfigDiscreteLevels.levels(4);
		config.tracker.klt.templateRadius = 3;

		config.tracker.detDesc.detectPoint.type = PointDetectorTypes.SHI_TOMASI;
		config.tracker.detDesc.detectPoint.general.maxFeatures = 600;
		config.tracker.detDesc.detectPoint.general.radius = 3;
		config.tracker.detDesc.detectPoint.general.threshold = 1;

		// Configure how visual odometry works
		config.thresholdAdd = 75;
		config.thresholdRetire = 2;
		config.ransac.iterations = 200;
		config.ransac.inlierThreshold = 1.5;

		// declares the algorithm
		MonocularPlaneVisualOdometry<GrayU8> visualOdometry = FactoryVisualOdometry.monoPlaneInfinity(config, GrayU8.class);

		// Pass in intrinsic/extrinsic calibration. This can be changed in the future.
		visualOdometry.setCalibration(calibration);

		// Process the video sequence and output the location plus number of inliers
		long startTime = System.nanoTime();
		while (video.hasNext()) {
			GrayU8 image = video.next();

			if (!visualOdometry.process(image)) {
				System.out.println("Fault!");
				visualOdometry.reset();
			}

			Se3_F64 leftToWorld = visualOdometry.getCameraToWorld();
			Vector3D_F64 T = leftToWorld.getT();

			System.out.printf("Location %8.2f %8.2f %8.2f, %s\n", T.x, T.y, T.z, trackStats(visualOdometry));
		}
		System.out.printf("FPS %4.2f\n", video.getFrameNumber()/((System.nanoTime() - startTime)*1e-9));
	}
}