Example Fiducial Square Image

• 

  Rendered 3D flat squares on top of fiducials

Demonstration how to detect square image fiducials. After the fiducial detector has been created a description of each image it detects is passed in. These images are converted into binary images and resized if needed. A large number of unique fiducials can be detected with a linear growth in computational time.

Example Code:

• ExampleFiducialImage.java

Concepts:

• Fiducials
• Pose estimation

Relevant Examples/Tutorials:

• Tutorial Fiducials
• Example Fiducial Square Binary
• Example Fiducial Square Hamming
• Example Fiducial Calibration Target

Videos

• Fiducial Overview

Example Code

/**
 * Detects square binary fiducials inside an image, writes out there pose, and visualizes a virtual flat cube
 * above them in the input image.
 *
 * @author Peter Abeles
 */
public class ExampleFiducialImage {
	public static void main( String[] args ) {
		String imagePath = UtilIO.pathExample("fiducial/image/examples/");
		String patternPath = UtilIO.pathExample("fiducial/image/patterns/");

//		String imageName = "image00.jpg";
		String imageName = "image01.jpg";
//		String imageName = "image02.jpg";

		// load the lens distortion parameters and the input image
		CameraPinholeBrown param = CalibrationIO.load(new File(imagePath, "intrinsic.yaml"));
		LensDistortionNarrowFOV lensDistortion = new LensDistortionBrown(param);
		BufferedImage input = UtilImageIO.loadImage(imagePath, imageName);
		GrayF32 original = ConvertBufferedImage.convertFrom(input, true, ImageType.single(GrayF32.class));

		// Detect the fiducial
		SquareImage_to_FiducialDetector<GrayF32> detector = FactoryFiducial.squareImage(
				new ConfigFiducialImage(), ConfigThreshold.local(ThresholdType.LOCAL_MEAN, 21), GrayF32.class);
//				new ConfigFiducialImage(), ConfigThreshold.fixed(100), GrayF32.class);

		// give it a description of all the targets
		double width = 4; // 4 cm
		detector.addPatternImage(loadImage(patternPath, "ke.png", GrayF32.class), 100, width);
		detector.addPatternImage(loadImage(patternPath, "dog.png", GrayF32.class), 100, width);
		detector.addPatternImage(loadImage(patternPath, "yu.png", GrayF32.class), 100, width);
		detector.addPatternImage(loadImage(patternPath, "yu_inverted.png", GrayF32.class), 100, width);
		detector.addPatternImage(loadImage(patternPath, "pentarose.png", GrayF32.class), 100, width);
		detector.addPatternImage(loadImage(patternPath, "text_boofcv.png", GrayF32.class), 100, width);
		detector.addPatternImage(loadImage(patternPath, "leaf01.png", GrayF32.class), 100, width);
		detector.addPatternImage(loadImage(patternPath, "leaf02.png", GrayF32.class), 100, width);
		detector.addPatternImage(loadImage(patternPath, "hand01.png", GrayF32.class), 100, width);
		detector.addPatternImage(loadImage(patternPath, "chicken.png", GrayF32.class), 100, width);
		detector.addPatternImage(loadImage(patternPath, "h2o.png", GrayF32.class), 100, width);
		detector.addPatternImage(loadImage(patternPath, "yinyang.png", GrayF32.class), 100, width);

		detector.setLensDistortion(lensDistortion, param.width, param.height);

		detector.detect(original);

		// print the results
		Graphics2D g2 = input.createGraphics();
		var targetToSensor = new Se3_F64();
		var locationPixel = new Point2D_F64();
		var bounds = new Polygon2D_F64();
		for (int i = 0; i < detector.totalFound(); i++) {
			detector.getCenter(i, locationPixel);
			detector.getBounds(i, bounds);

			g2.setColor(new Color(50, 50, 255));
			g2.setStroke(new BasicStroke(10));
			VisualizeShapes.drawPolygon(bounds, true, 1.0, g2);

			if (detector.hasID())
				System.out.println("Target ID = " + detector.getId(i));
			if (detector.hasMessage())
				System.out.println("Message   = " + detector.getMessage(i));
			System.out.println("2D Image Location = " + locationPixel);

			if (detector.is3D()) {
				detector.getFiducialToCamera(i, targetToSensor);
				System.out.println("3D Location:");
				System.out.println(targetToSensor);
				VisualizeFiducial.drawCube(targetToSensor, param, detector.getWidth(i), 3, g2);
				VisualizeFiducial.drawLabelCenter(targetToSensor, param, "" + detector.getId(i), g2);
			} else {
				VisualizeFiducial.drawLabel(locationPixel, "" + detector.getId(i), g2);
			}
		}

		ShowImages.showWindow(input, "Fiducials", true);
	}
}