What are Fiducial Markers in Computer Vision?

Fiducial markers are objects or features that are used as reference points in computer vision and image processing tasks. These markers are typically small, distinctive, and easy to identify, and they are placed in the scene intentionally to provide a known point of interest for the computer vision system to track or align with.

Fiducial markers can be used for a variety of purposes, such as:

1. Object tracking: By placing fiducial markers on an object, a computer vision system can track the object's movement and orientation over time.
2. Camera calibration: Fiducial markers can be used to calibrate a camera, allowing the system to determine its intrinsic and extrinsic parameters (such as distortion coefficients and rotation/translation vectors).
3. 3D reconstruction: Fiducial markers can be used to estimate the 3D shape of an object or scene by triangulating their positions in multiple views.
4. Registration: Fiducial markers can be used to align multiple images or videos taken from different viewpoints or at different times.

Examples of fiducial markers include:

1. Corners or edges of objects: These can be easily detected and tracked over time.
2. Patterns or logos: Companies often place their logos or specific patterns on products to use as fiducial markers.
3. Checkerboard patterns: A checkerboard pattern can be used as a fiducial marker, as the squares can be easily detected and tracked.
4. QR codes: QR codes are a type of fiducial marker that can be read by a computer vision system to provide information about the object or scene.

Overall, fiducial markers are an important tool in computer vision and image processing, allowing systems to accurately track and align objects and scenes over time.