Patent ID: 11896368
Assignee: APPLE INC.
Field: Medical technology (Instruments)
Classification: CPC A  G  H | IPC A  G  H

Claim 9:
10. A method comprising:
receiving, by a processor circuit of a wearable device worn on a wrist of a user during a swimming session, motion data from one or more motion sensors of the wearable device;
determining, by the processor circuit using the motion data, a first set of rotational data of the wearable device, wherein the first set of rotational data is expressed in a first frame of reference;
converting, by the processor circuit, the first set of rotational data into a second set of rotational data, wherein the second set of rotational data is expressed in a second frame of reference, and wherein the second set of rotational data includes data indicative of the user's arm or wrist movements;
determining, by the processor circuit, one or more swimming metrics of the user based on the second set of rotational data, where determining the one or more swimming metrics includes:
detecting a number of turns and a number of strokes of the user during the swimming session based on the received motion data;
determining a number of strokes per lap based on the number of turns and the number of strokes;
determining a variance of the number of strokes per lap;
adjusting the number of turns to reduce the variance of the number of strokes per lap;
determining a lap count of the user based on the adjusted number of turns; and

outputting, by the processor circuit, the one or more swimming metrics of the user.