US Patent 11978275 Methods and apparatus to monitor environments

Methods and apparatus to monitor environments are disclosed. Example audience measurement devices disclosed herein execute, in connection with a first frame of data, a three-dimensional recognition analysis on an object detected in an environment within a threshold distance from a sensor. Disclosed example audience measurement devices also detect that the object has moved outside the threshold distance from the sensor in a second frame subsequent to the first frame. Disclosed example audience measurement devices further execute a two-dimensional recognition analysis on the object in the second frame.