Measuring method and device

An apparatus for determining movement information for a user that carries an accelerometer whilst moving, the apparatus comprising one or more processors and memory configured to:

• receive acceleration data from the accelerometer, the acceleration data defining accelerations experienced by the accelerometer resulting from movement of the user, the accelerations being defined relative to a frame of reference associated with the accelerometer;
• apply a transformation for transforming the frame of reference to a frame of reference of the user that includes a purported direction of travel of the user and a side to side direction transverse to the purported direction of travel of the user to provide transformed acceleration data or transformed data derived from the acceleration data that includes i) acceleration data for accelerations in said purported direction of travel, and ii) acceleration data for accelerations in said side to side direction;
• determine a first autocorrelation function of the acceleration data or of the transformed acceleration data;
• determine a second autocorrelation function of said acceleration data for accelerations in said purported direction of travel that is included in said transformed acceleration data;
• determine a third autocorrelation function of said acceleration data for accelerations in said side to side direction that is included in said transformed acceleration;
• and
• determine if the user is walking or not walking or running or not running using the first, second and third autocorrelation functions.

A method for determining movement information for a user that carries an accelerometer whilst moving, the method comprising:

• receiving acceleration data from the accelerometer, the acceleration data defining accelerations experienced by the accelerometer resulting from movement of the user, the accelerations being defined relative to a frame of reference associated with the accelerometer;
• processing the acceleration data, including:
• applying a transformation for transforming the frame of reference to a frame of reference of the user that includes a direction of travel of the user and a side to side direction transverse to the direction of travel of the user to provide transformed data;
• processing the transformed data or the transformed data to determine information about accelerations in said side to side direction;
• determining an autocorrelation function or a frequency function;
• and
• determining a time period corresponding to a maximum peak in the autocorrelation function or the frequency function, wherein the determined time period is ambiguous and corresponds either to a stride period or to a step period of the user as the user is walking or running;
• and
• using said information about accelerations in said side to side direction to disambiguate whether the determined time period corresponds to the stride period of the user or to the step period of the user.

A method for determining movement information for a user that carries an accelerometer whilst moving, the method comprising:

• receiving acceleration data from the accelerometer, the acceleration data defining accelerations experienced by the accelerometer resulting from movement of the user, the accelerations being defined relative to a frame of reference associated with the accelerometer;
• applying a transformation for transforming the frame of reference to a frame of reference of the user that includes a purported direction of travel of the user and a side to side direction transverse to the purported direction of travel of the user to provide transformed acceleration data that includes i) acceleration data for accelerations in said purported direction of travel, and ii) acceleration data for accelerations in said side to side direction;
• determining a first autocorrelation function of the acceleration data or of the transformed acceleration data;
• determining a second autocorrelation function of said acceleration data for accelerations in said purported direction of travel that is included in said transformed acceleration data;
• determining a third autocorrelation function of said acceleration data for accelerations in said side to side direction that is included in said transformed acceleration data;
• and
• determining if the user is walking or not walking or running or not running using the first, second and third autocorrelation functions.