🎁 Get the FREE AI Skills Starter Guide β€” Subscribe β†’
BytesAgainBytesAgain
πŸ¦€ ClawHub

Pywayne Cv Apriltag Detector

by @wangyendt

AprilTag corner detection for camera calibration and pose estimation. Use when working with pywayne.cv.apriltag_detector module to detect AprilTag fiducial m...

Versionv0.1.0
Downloads747
TERMINAL
clawhub install apriltag-detector

πŸ“– About This Skill


name: pywayne-cv-apriltag-detector description: AprilTag corner detection for camera calibration and pose estimation. Use when working with pywayne.cv.apriltag_detector module to detect AprilTag fiducial markers in images, with automatic library installation via gettool, drawing detection results with corners and IDs, and support for both file paths and numpy arrays.

Pywayne AprilTag Detector

This module detects AprilTag fiducial markers for camera calibration and pose estimation.

Quick Start

from pywayne.cv.apriltag_detector import ApriltagCornerDetector

Create detector

detector = ApriltagCornerDetector()

Detect from file path

detections = detector.detect('test.png', show_result=True)

Detect from numpy array

import cv2 image = cv2.imread('test.png') detections = detector.detect(image)

Detection Methods

detect()

Detect AprilTags in an image:

detections = detector.detect(
    image,           # File path, Path object, or numpy array
    show_result=False  # Show visualization window
)

Returns list of detection results with:

  • id: Tag ID
  • hamming_distance: Detection confidence
  • center: Tag center coordinates (x, y)
  • corners: 4 corner coordinates
  • detect_and_draw()

    Detect AprilTags and draw results on original image:

    result_image = detector.detect_and_draw(image)
    cv2.imshow('Detection Result', result_image)
    cv2.waitKey(0)
    

    Visualization includes:

  • Green polygon outlines
  • Red corner circles
  • Red ID labels at tag centers
  • Requirements

  • cv2 (OpenCV) - Image processing
  • numpy - Array operations
  • gettool - Downloads apriltag_detection library automatically
  • Library Installation

    The detector automatically checks for and installs the apriltag_detection library using gettool if not found.

    Detection Result Format

    Each detection contains:

    | Field | Description | |--------|-------------| | id | Tag identifier | | hamming_distance | Hamming distance (lower = more confident) | | center | Tag center as (x, y) tuple | | corners | 4 corner coordinates as [(x1, y1), (x2, y2), (x3, y3), (x4, y4)] |

    Notes

  • Supports both grayscale and BGR images
  • Automatic grayscale conversion for detection
  • Visualization sizes scale with image dimensions
  • Uses AprilTag 36h11 tag family
  • πŸ’‘ Examples

    from pywayne.cv.apriltag_detector import ApriltagCornerDetector

    Create detector

    detector = ApriltagCornerDetector()

    Detect from file path

    detections = detector.detect('test.png', show_result=True)

    Detect from numpy array

    import cv2 image = cv2.imread('test.png') detections = detector.detect(image)

    πŸ“‹ Tips & Best Practices

  • Supports both grayscale and BGR images
  • Automatic grayscale conversion for detection
  • Visualization sizes scale with image dimensions
  • Uses AprilTag 36h11 tag family