Family Fiducial
No, that’s not the title for a new italian sitcom. I’ve chosen it because the day before yesterday I received my acrylic pucks and started to make a set of fiducials.
I bought these pucks here and here on ebay. The have a thickness of 8 mm and a diameter respectively a edge length of 60 mm. I’ve found no thicker option (for such a good price). They cost only 22,30 Euro for 10 round and 5 squared pucks including shipping.
After sticking the fiducial markers to the LED-cubes and a round puck with double-sided tape, I varnished them with “zapon varnish”, which is normally used to prevent metals from tarnishing.
The zapon varnish is clear and meant to function as a protective layer above the marker to prevent it from scrubbing. As you may see on the right, the paper gets a bit grey after varnishing, because it seems to absorb the moisture from the varnish.
After testing the varnish on the puck in the lower right corner, I had to go on on another 14 pucks. I hated it, because at best you varnish every puck two to four times.
A glossy picture of the fiducial family. One important thing in the end: the zapon varnish seems to be a bit impatient with the acrylic. As you may see on this picture (click to enlarge) nearly every puck has flaws on the edges. That doesn’t look very nice, but they will still do their job. My father told me that it could have something to do with the different surface tension of varnish and acrylic.