US Patent 11363971 Systems and methods for estimating a three-dimensional pose

A motion tracking element for an oral hygiene element such as a toothbrush. The motion tracking element may be detachably coupled to the oral hygiene element. The motion tracking element may include a body having an outer surface, a portion of the outer surface having a pattern that includes a plurality of indicators with a non-circular shape. The indicators may be flush with and form part of the outer surface. A plurality of visual markers may be located on the outer surface, each of the visual markers having a circular shape. The plurality of visual markers may be formed integrally with the body. A method for estimating a pose of an oral hygiene device may be achieved using the motion tracking element.