# Example Fiducial Square Image

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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:

Concepts:

• Fiducials
• Pose estimation

Relevant Tutorials:

Relevant Applets:

# 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 directory = "../data/applet/fiducial/image/";

String imageName = "image0000.jpg";
//		String imageName = "image0001.jpg";
//		String imageName = "image0002.jpg";

// load the lens distortion parameters and the input image
IntrinsicParameters param = UtilIO.loadXML(directory + "intrinsic.xml");
BufferedImage input = UtilImageIO.loadImage(directory + imageName);
ImageFloat32 original = ConvertBufferedImage.convertFrom(input, true, ImageType.single(ImageFloat32.class));

// Detect the fiducial
SquareImage_to_FiducialDetector<ImageFloat32> detector = FactoryFiducial.
squareImageRobust(new ConfigFiducialImage(0.1), 6, ImageFloat32.class);
//				squareImageFast(new ConfigFiducialImage(0.1), 100, ImageFloat32.class);

// give it a description of all the targets
ImageFloat32 dog = UtilImageIO.loadImage(directory + "dog.png",ImageFloat32.class);
// uncomment to detect the text target
ImageFloat32 text = UtilImageIO.loadImage(directory + "text.png",ImageFloat32.class);

detector.setIntrinsic(param);

detector.detect(original);

// print the results
Graphics2D g2 = input.createGraphics();
Se3_F64 targetToSensor = new Se3_F64();
for (int i = 0; i < detector.totalFound(); i++) {
System.out.println("Target ID = "+detector.getId(i));
detector.getFiducialToWorld(i, targetToSensor);
System.out.println("Location:");
System.out.println(targetToSensor);

VisualizeFiducial.drawCube(targetToSensor,param,0.1,g2);
}

ShowImages.showWindow(input,"Fiducials");

}
}
```