Determining a level of interaction experienced by a subject

An apparatus for determining a level of interaction experienced by a subject, the apparatus comprising:

• a processor configured to:
• receive first location data indicative of a location of a first device relative to at least one reference location, the first device being associated with the body of a first subject;
• obtain first relative orientation data indicative of an orientation of the first device relative to a facing direction of the first subject, the first relative orientation data comprising data acquired in respect of an orientation of the first device relative to the facing direction of the first subject over a historic period of time;
• receive first orientation data indicative of an orientation of the first device relative to a first reference frame;
• receive second location data indicative of a location of a second device relative to at least one reference location;
• receive second orientation data indicative of an orientation of the second device relative to a second reference frame;
• determine, based on the obtained first relative orientation data and the first orientation data, an indication of an absolute orientation of the first subject with respect to the first reference frame;
• and
• determine, based on the first location data, the second location data, the second orientation data and the indication of the absolute orientation of the first subject, a level of interaction between the first subject and the second device.

A system comprising:

• a first device configured to be worn on the body of a first subject;
• a second device;
• processing apparatus configured to:
• receive first location data indicative of a location of the first device relative to at least one reference location;
• obtain first relative orientation data indicative of an orientation of the first device relative to a facing direction of the first subject, the first relative orientation data comprising data acquired in respect of an orientation of the first device relative to the facing direction of the first subject over a historic period of time;
• receive first orientation data indicative of an orientation of the first device relative to a first reference frame;
• receive second location data indicative of a location of the second device relative to at least one reference location;
• receive second orientation data indicative of an orientation of the second device relative to a second reference frame;
• determine, based on the obtained first relative orientation data and the first orientation data, an indication of an absolute orientation of the first subject with respect to the first reference frame;
• and
• determine, based on the first location data, the second location data, the second orientation data and the indication of the absolute orientation of the first subject, a level of interaction between the first subject and the second device.