apriltag-node

Node.js bindings for the AprilTag fiducial marker detection library.

Usage

Install the @monumental-works/apriltag-node NPM package.

import AprilTag, { FAMILIES } from '@monumental-works/apriltag-node';

// Create detector with default tag36h11 family
const detector = new AprilTag();

// Or specify family and options
const detector = new AprilTag(FAMILIES.TAG36H11, {
  quadDecimate: 2.0,
  quadSigma: 0.0,
  refineEdges: true,
  decodeSharpening: 0.25,
});

// Detect tags in grayscale image
const detections = detector.detect(width, height, imageBuffer);

detections.forEach((detection) => {
  console.log(`Tag ID: ${detection.id}`);
  console.log(`Center: [${detection.center[0]}, ${detection.center[1]}]`);
  console.log(`Corners:`, detection.corners);
});

API

Constructor

new AprilTag(family?, options?)

• family: Tag family (default: FAMILIES.TAG36H11)
• options: Detection options
  • quadDecimate: Quad decimation factor
  • quadSigma: Gaussian blur sigma
  • refineEdges: Enable edge refinement
  • decodeSharpening: Decode sharpening factor

Methods

• detect(width, height, imageData): Detect tags in grayscale image
• setQuadDecimate(value): Set quad decimation
• setQuadSigma(value): Set Gaussian blur sigma
• setRefineEdges(value): Enable/disable edge refinement
• setDecodeSharpening(value): Set decode sharpening

Supported Tag Families

• tag36h11 (default) - Recommended for general use
• tag25h9 - Good balance of performance and robustness
• tag16h5 - Fewer unique tags available
• tagCircle21h7 - Circular design
• tagStandard41h12 - Standard format
• tagCircle49h12 - Large lookup table with 49-bit codes
• tagCustom48h12 - Large lookup table with 48-bit codes
• tagStandard52h13 - Largest family with 52-bit codes

License

This project is licensed under the MIT License - see the LICENSE file for details.

AprilTag Library

This package includes the AprilTag library developed by the APRIL Robotics Laboratory at the University of Michigan. The AprilTag library is licensed under the BSD 2-Clause License.

AprilTag Citation:

@INPROCEEDINGS{wang2016iros,
  author = {John Wang and Edwin Olson},
  title = {{AprilTag 2: Efficient and robust fiducial detection}},
  booktitle = {Proceedings of the {IEEE} International Conference on Robotics and
               Automation ({ICRA})},
  year = {2016},
  month = {May},
}

For more information about AprilTag, visit: https://april.eecs.umich.edu/software/apriltag