Abstract: A method for instantly determining the mutual geometric positions and orientations between a plurality of 3D motion capture sensors has three or more reference markers mounted fixedly relative to each other on substantially one single plane which are sensed by each sensor. Said method enables said sensors to cooperate as a larger sensing system for 3D motion capture applications without requiring said sensors to be mounted rigidly relative to each other.

Abstract: A sensor for determining a one-dimensional component of the angular orientation of a radiation source relative to the sensor has a radiation sensitive element which produces an electrical signal representative of radiation incidence upon the element. A radiation-opaque mask is mounted between the element and the radiation source. A first plurality of parallel slit apertures are provided in the mask. The slits are spaced relative to one another, and the element is aligned relative to the mask, such that radiation emitted by the source through at least one of the slits is simultaneously incident upon at least two independent radiation-sensitive points on the element while the source is within an intended operational range of the sensor; and, the points are displaced from the one slit by different distances.