How about those ArUco markers, what is there to say? They are the least informative square marker. Even a barcode gives your more information. But they have a purpose and that is to help computer vision technology locate a specific point in space. ArUco markers and similar alternatives are all around us. Some in malls and others on NASA space equipment.

They come in different grid sizes. I finally settled on a 7x7 grid. When printed on half to full-size letter paper, they can easily mark the edges of a good size back yard and that is exactly how we used them.

During testing, we put them through their paces. We started with ones about an inch in size. We tested them in different configurations in different light conditions. Markers with a lower numerical value seemed to be able to be seen at a farther distance compared to those with a larger value. The markers pictured are slightly smaller than a half sheet of letter-size paper (about 5 inches).

These markers worked out really well. Sheldon, the Tibetian Spainial pictured above, was given treats for being such a good model. The picture is a frame from the OAK-D Lite camera. The frame is 300x300 pixels in size. We use a smaller image to speed up detection and classification results.