Using AprilTags with the AI Vision Sensor – VEX Library

AprilTag IDs are visual markers designed for easy detection and identification by computer vision systems. These square tags feature a unique black and white pattern that allows cameras and software to quickly recognize them and determine their precise position and orientation in 3D space.

Note: Unlike Color Signatures and Color Codes, AprilTag IDs don’t require any setup in the AI Vision Utility. The VEX AIM Coding Robot will detect AprilTag IDs right away.

The AI Vision Utility window in VEXcode AIM, showing the live camera view in the window to the left, featuring three April Tags.

VEX AIM includes five purple AprilTag IDs, each with a unique number that allows the AI Vision Sensor to distinguish between them. These AprilTag IDs can be used for navigating around the field and for identifying points of interest.

If you need additional AprilTag IDs, visit printables.vex.com to download and print higher-numbered IDs (up to 37).

AprilTag IDs have access to 10 different properties for use when coding:

width
height
centerX
centerY
bearing
rotation
originX
originY
id
score

For information what these properties are and using them in a VEXcode project, check out the VEX AIM API Reference Site for Blocks or Python.

More detail about how to understand the data from the AI Vision Sensor can be found here.