Method and system for resolving hemisphere ambiguity using a position vector
Embodiments resolve hemisphere ambiguity at a system comprising sensors. A hand-held controller of the system emits magnetic fields. Sensors positioned within a headset of the system detect the magnetic fields. A first position and orientation of the hand-held controller is determined within a first hemisphere with respect to the headset based on the magnetic fields. A second position and orientation of the hand-held controller is determined within a second hemisphere, diametrically opposite the first hemisphere, with respect to the headset based on the magnetic fields. A normal vector is determined with respect to the headset, and a position vector identifying a position of the hand-held controller with respect to the headset in the first hemisphere. A dot-product of the normal vector and the position vector is calculated, and the first position and orientation of the hand-held controller is determined to be accurate when a result of the dot-product is positive.
1. A method of resolving hemisphere ambiguity at a system comprising one or more sensors, the method comprising:
emitting, at a hand-held controller of the system, one or more magnetic fields;
detecting, by one or more sensors positioned within a headset of the system, the one or more magnetic fields;
determining a first position and a first orientation of the hand-held controller within a first hemisphere with respect to the headset based on the one or more magnetic fields;
determining a second position and a second orientation of the hand-held controller within a second hemisphere with respect to the headset based on the one or more magnetic fields, wherein the second hemisphere is diametrically opposite the first hemisphere with respect to the headset;
determining a normal vector with respect to the headset, and a position vector identifying a position of the hand-held controller with respect to the headset in the first hemisphere;
calculating a dot-product of the normal vector and the position vector;
determining that the first position and the first orientation of the hand-held controller is accurate when a result of the dot-product is positive; and
determining that the second position and the second orientation of the hand-held controller is accurate when the result of the dot-product is negative.
2. The method of claim 1 , wherein the position vector is defined at a coordinate frame of the headset.
3. The method of claim 1 , wherein the normal vector originates from the headset and extends at a predetermined angle from a horizontal line from the headset.
4. The method of claim 3 , wherein the predetermined angle is 45° angle down from the horizontal line from the headset.
5. The method of claim 1 , wherein when the result of the dot-product is positive, the first hemisphere is identified as a front hemisphere with respect to the headset and the second hemisphere is identified as a back hemisphere with respect to the headset.
6. The method of claim 1 , wherein when the result of the dot-product is negative, the second hemisphere is identified as a front hemisphere with respect to the headset and the first hemisphere is identified as a back hemisphere with respect to the headset.
7. The method of claim 1 , further comprising:
delivering virtual content to a display based on:
the first position and the first orientation when the result of the dot-product is positive; or
the second position and the second orientation when the result of the dot-product is negative.
8. The method of claim 1 , wherein the system is an optical device.
9. The method of claim 1 , wherein the method is performed during an initialization process of the headset.
10. A system comprising:
a hand-held controller comprising a magnetic field transmitter configured to emit one or more magnetic fields;
a headset comprising one or more magnetic field sensors configured to detect the one or more magnetic fields;
a processor coupled to the headset configured to perform operations including:
determining a first position and a first orientation of the hand-held controller within a first hemisphere with respect to the headset based on the one or more magnetic fields;
determining a second position and a second orientation of the hand-held controller within a second hemisphere with respect to the headset based on the one or more magnetic fields, wherein the second hemisphere is diametrically opposite the first hemisphere with respect to the headset;
determining a normal vector with respect to the headset, and a position vector identifying a position of the hand-held controller with respect to the headset in the first hemisphere;
calculating a dot-product of the normal vector and the position vector;
determining that the first position and the first orientation of the hand-held controller is accurate when a result of the dot-product is positive; and
determining that the second position and the second orientation of the hand-held controller is accurate when the result of the dot-product is negative.
11. The system of claim 10 , wherein the position vector is defined at a coordinate frame of the headset.
12. The system of claim 10 , wherein the normal vector originates from the headset and extends at a predetermined angle from a horizontal line from the headset.
13. The system of claim 12 , wherein the predetermined angle is 45° angle down from the horizontal line from the headset.
14. The system of claim 10 , wherein when the result of the dot-product is positive, the first hemisphere is identified as a front hemisphere with respect to the headset and the second hemisphere is identified as a back hemisphere with respect to the headset.
15. The system of claim 10 , wherein when the result of the dot-product is negative, the second hemisphere is identified as a front hemisphere with respect to the headset and the first hemisphere is identified as a back hemisphere with respect to the headset.
16. The system of claim 10 , wherein the processor is further configured to perform operations including:
delivering virtual content to a display based on:
the first position and the first orientation when the result of the dot-product is positive; or
the second position and the second orientation when the result of the dot-product is negative.
17. The system of claim 10 , wherein the system is an optical device.
18. The system of claim 10 , wherein the operations are performed during an initialization process of the headset.
19. A computer-program product embodied in a non-transitory computer-readable medium, the computer-readable medium having stored thereon a sequence of instructions which, when executed by a processor, causes the processor to execute a method for resolving hemisphere ambiguity at a system comprising one or more sensors comprising:
emitting, at a hand-held controller of the system, one or more magnetic fields;
detecting, by one or more sensors positioned within a headset of the system, the one or more magnetic fields;
determining a first position and a first orientation of the hand-held controller within a first hemisphere with respect to the headset based on the one or more magnetic fields;
determining a second position and a second orientation of the hand-held controller within a second hemisphere with respect to the headset based on the one or more magnetic fields, wherein the second hemisphere is diametrically opposite the first hemisphere with respect to the headset;
determining a normal vector with respect to the headset, and a position vector identifying a position of the hand-held controller with respect to the headset in the first hemisphere;
calculating a dot-product of the normal vector and the position vector;
determining that the first position and the first orientation of the hand-held controller is accurate when a result of the dot-product is positive; and
determining that the second position and the second orientation of the hand-held controller is accurate when the result of the dot-product is negative.