machinevisiontoolbox.Image.fiducial

Image.fiducial(dict='4x4_1000', K=None, side=None)

Find fiducial markers in image

Parameters:

dict (str, optional) – marker type, defaults to “4x4_1000”
K (ndarray(3,3), optional) – camera intrinsics, defaults to None
side (float, optional) – side length of the marker, defaults to None

Returns:

markers found in image

Return type:

list of Fiducial instances

Find ArUco or ApriTag markers in the scene and return a list of Fiducial objects, one per marker. If camera intrinsics are provided then also compute the marker pose with respect to the camera.

dict specifies the marker family or dictionary and describes the number of bits in the tag and the number of usable unique tags.

dict	tag type	marker size	number of unique tags
`4x4_50`	Aruco	4x4	50
`4x4_100`	Aruco	4x4	100
`4x4_250`	Aruco	4x4	250
`4x4_1000`	Aruco	4x4	1000
`5x5_50`	Aruco	5x5	50
`5x5_100`	Aruco	5x5	100
`5x5_250`	Aruco	5x5	250
`5x5_1000`	Aruco	5x5	1000
`6x6_50`	Aruco	6x6	50
`6x6_100`	Aruco	6x6	100
`6x6_250`	Aruco	6x6	250
`6x6_1000`	Aruco	6x6	1000
`7x7_50`	Aruco	7x7	50
`7x7_100`	Aruco	7x7	100
`7x7_250`	Aruco	7x7	250
`7x7_1000`	Aruco	7x7	1000
`original`	Aruco	?	?
`16h5`	AprilTag	4x4	30
`25h9`	AprilTag	5x5	35
`36h10`	AprilTag	6x6	?
`36h11`	AprilTag	6x6	587

Example:

  File "/opt/hostedtoolcache/Python/3.9.20/x64/lib/python3.9/code.py", line 90, in runcode
    exec(code, self.locals)
  File "<input>", line 1, in <module>
NameError: name 'fiducials' is not defined
Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.9.20/x64/lib/python3.9/code.py", line 90, in runcode
    exec(code, self.locals)
  File "<input>", line 1, in <module>
NameError: name 'fiducials' is not defined

Note:

side is the dimension of the square that contains the small white squares inside the black background.

References:

Robotics, Vision & Control for Python, Section 13.6.1, P. Corke, Springer 2023.

Seealso:

Fiducial