Calculating homography of multiple markers on a single plane
I've got an algorithm that calculates the homography of a number of markers in a single image, using OpenCV's findHomography. This works fine, but due to the size of the markers/resolution of the images, the rotation calculated is often quite inaccurate (mainly around the x and z axes of the marker, assuming y is up). I'd love to find a way to improve this.
I have a hypothesis that the fact that I know all the markers are on the same plane (they're on a table) should help improve the homography - I then just need to work out the rotation of the marker around a single axis - but I don't know enough to put this in to practice. Can anyone give me any guidance on this?
Do you know the relative position of the markers on the table?
Before the call to findHomography, I have the points that make up the shape that I'm detecting in screen space.