Patent ID: 9658692
Date: 2017-05-23
CPC Classifications: G01R,G02B,G06F,G06T

Claim:
1. In a wearable head-mounted display (HMD) having a processor, a magnetometer device with three orthogonal measurement axes, and a motion detector, a computer-implemented method comprising: during motion of a hand-wearable magnet (HWM) in a gesture detection region of the wearable HMD, measuring orthogonal magnetic field components of a magnetic field vector with the magnetometer device at consecutive discrete times; during the motion of the HWM in the gesture detection region of the wearable HMD, determining rotational motion of the wearable HMD as measured by the motion detector at each of the consecutive discrete times; determining discrete differences between successive samples of the measured orthogonal magnetic field components; correcting each of the discrete differences for changes in the measured orthogonal magnetic field components due to the determined rotational motion of the wearable HMD to obtain corrected discrete differences; computing discrete time derivatives of the measured orthogonal magnetic field components from the corrected discrete differences to obtain a triplet of sequences of discrete time derivatives; making a comparison of the computed discrete time derivatives with one or more sets of pre-determined time derivatives of magnetic field strength, each of the one or more sets being stored at the wearable HMD and each being associated with a respective known gesture; and upon matching the computed discrete time derivatives with a particular set of the one or more sets based on the comparison, identifying the respective known gesture associated with the particular set.