Example Visual Odometry Depth

This example demonstrates how to estimate the camera's ego motion using an RGB-D sensor, such as the Kinect, which contains visual and depth information.

Example Code:

• ExampleVisualOdometryDepth.java

Concepts:

• RGB-D

Relevant Videos:

• YouTube

Related Examples:

• Visual Odometry Monocular Plane
• Visual Odometry Stereo

Example Code

/**
 * Bare bones example showing how to estimate the camera's ego-motion using a depth camera system, e.g. Kinect.
 * Additional information on the scene can be optionally extracted from the algorithm if it implements AccessPointTracks3D.
 *
 * @author Peter Abeles
 */
public class ExampleVisualOdometryDepth {

	public static void main( String[] args ) {

		MediaManager media = DefaultMediaManager.INSTANCE;

		String directory = UtilIO.pathExample("kinect/straight");

		// load camera description and the video sequence
		VisualDepthParameters param = CalibrationIO.load(
				media.openFile(new File(directory , "visualdepth.yaml").getPath()));

		// specify how the image features are going to be tracked
		ConfigPKlt configKlt = new ConfigPKlt();
		configKlt.pyramidLevels = ConfigDiscreteLevels.levels(4);
		configKlt.templateRadius = 3;

		ConfigPointDetector configDet = new ConfigPointDetector();
		configDet.type = PointDetectorTypes.SHI_TOMASI;
		configDet.shiTomasi.radius = 3;
		configDet.general.maxFeatures = 600;
		configDet.general.radius = 3;
		configDet.general.threshold = 1;

		PointTracker<GrayU8> tracker = FactoryPointTracker.klt(configKlt, configDet, GrayU8.class, GrayS16.class);

		DepthSparse3D<GrayU16> sparseDepth = new DepthSparse3D.I<>(1e-3);

		// declares the algorithm
		DepthVisualOdometry<GrayU8,GrayU16> visualOdometry =
				FactoryVisualOdometry.depthDepthPnP(1.5, 120, 2, 200, 50, true,
				sparseDepth, tracker, GrayU8.class, GrayU16.class);

		// Pass in intrinsic/extrinsic calibration.  This can be changed in the future.
		visualOdometry.setCalibration(param.visualParam,new DoNothing2Transform2_F32());

		// Process the video sequence and output the location plus number of inliers
		SimpleImageSequence<GrayU8> videoVisual = media.openVideo(
				new File(directory ,"rgb.mjpeg").getPath(), ImageType.single(GrayU8.class));
		SimpleImageSequence<GrayU16> videoDepth = media.openVideo(
				new File(directory , "depth.mpng").getPath(), ImageType.single(GrayU16.class));

		while( videoVisual.hasNext() ) {
			GrayU8 visual = videoVisual.next();
			GrayU16 depth = videoDepth.next();

			if( !visualOdometry.process(visual,depth) ) {
				throw new RuntimeException("VO Failed!");
			}

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

			System.out.printf("Location %8.2f %8.2f %8.2f      inliers %s\n", T.x, T.y, T.z, inlierPercent(visualOdometry));
		}
	}

	/**
	 * If the algorithm implements AccessPointTracks3D, then count the number of inlier features
	 * and return a string.
	 */
	public static String inlierPercent(VisualOdometry alg) {
		if( !(alg instanceof AccessPointTracks3D))
			return "";

		AccessPointTracks3D access = (AccessPointTracks3D)alg;

		int count = 0;
		int N = access.getTotalTracks();
		for( int i = 0; i < N; i++ ) {
			if( access.isTrackInlier(i) )
				count++;
		}

		return String.format("%%%5.3f", 100.0 * count / N);
	}
}