AprilRobotics / apriltag

AprilTag is a visual fiducial system popular for robotics research.
https://april.eecs.umich.edu/software/apriltag
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What do the tag-specific hex codes in the c files represent? #282

Open joellyons opened 1 year ago

joellyons commented 1 year ago

What do the tag-specific hex codes in the c files represent? For example, in tag25h9.c, tag 0's code is represented as 0x156f1f4. I assumed that each bit in that number (1010101101111000111110100) represented a block in tag 0's visual representation starting at top left and moving left to right, top to bottom, where 1 is a black square and 0 is white.

But, if I render it that way, I end up with this: image

instead of what I see in apriltag-imgs, which is this: image

Are the graphics in apriltag-imgs outdated? Or am I misinterpreting the numeric values in tag25h9.c?