Distance measurement
First Claim
1. A method of determining a distance between a device and an object, the method comprising:
- emitting an acoustic reference signal from a speaker of the device;
receiving an acoustic input signal at a microphone of the device, the acoustic input signal including a measurement portion including a reflection of the acoustic reference signal off the object;
cross correlating at least the measurement portion with the emitted acoustic reference signal to provide a cross correlated signal;
receiving estimated time of flight information relating to the object;
extracting a section of the cross correlated signal corresponding to the reflection of the acoustic reference signal by the object, based on the received estimated time of flight information;
analyzing the extracted section of the cross correlated signal to determine a time of flight between emitting the acoustic reference signal and receiving the reflection wherein analyzing includes detecting a center of gravity of the extracted section of the cross correlated signal, determining a time of the center of gravity of the extracted section of the cross correlated signal, and determining a time of flight based on a time difference between the time of the center of gravity of the extracted section of the cross correlated signal and a first time at which the acoustic reference signal was emitted; and
determining the distance between the device and the object based on the determined time of flight and known characteristics of the acoustic reference signal.
2 Assignments
0 Petitions
Accused Products
Abstract
A method for determining a distance between a device and an object, the method comprising: emitting an acoustic reference signal from a speaker of the device; receiving an acoustic input signal at a microphone of the device, the acoustic input signal including a measurement portion including a reflection of the acoustic reference signal off the object; cross correlating at least the measurement portion with the emitted acoustic reference signal to provide a cross correlated signal; receiving information relating to the object; extracting a section of the cross correlated signal corresponding to reflection of the acoustic reference signal by the object, based on the received information; analyzing the extracted section of the cross correlated signal to determine a time of flight between emitting the acoustic reference signal and receiving the reflection; and determining the distance between the device and the object based on the determined time of flight and known characteristics of the acoustic reference signal. A chipset for performing the method is also disclosed.
25 Citations
16 Claims
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1. A method of determining a distance between a device and an object, the method comprising:
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emitting an acoustic reference signal from a speaker of the device; receiving an acoustic input signal at a microphone of the device, the acoustic input signal including a measurement portion including a reflection of the acoustic reference signal off the object; cross correlating at least the measurement portion with the emitted acoustic reference signal to provide a cross correlated signal; receiving estimated time of flight information relating to the object; extracting a section of the cross correlated signal corresponding to the reflection of the acoustic reference signal by the object, based on the received estimated time of flight information; analyzing the extracted section of the cross correlated signal to determine a time of flight between emitting the acoustic reference signal and receiving the reflection wherein analyzing includes detecting a center of gravity of the extracted section of the cross correlated signal, determining a time of the center of gravity of the extracted section of the cross correlated signal, and determining a time of flight based on a time difference between the time of the center of gravity of the extracted section of the cross correlated signal and a first time at which the acoustic reference signal was emitted; and determining the distance between the device and the object based on the determined time of flight and known characteristics of the acoustic reference signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 16)
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14. A chipset including instructions fixed in a non-transitory tangible medium configured to enable a mobile communications device to determine a distance between the mobile communications device and an object, the non-transitory tangible medium comprising:
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instructions for emitting an acoustic reference signal from a speaker of the mobile communications device; instructions for receiving an acoustic input signal at a microphone of the mobile communications device, the acoustic input signal including a measurement portion including a reflection of the acoustic reference signal off the object; instructions for cross correlating at least the measurement portion with the emitted acoustic reference signal to provide a cross correlated signal; instructions for receiving estimated time of flight information relating to the object; instructions for extracting a section of the cross correlated signal corresponding to reflection of the acoustic reference signal by the object, based on the received estimated time of flight information; instructions for analyzing the extracted section of the cross correlated signal to determine a time of flight between emitting the acoustic reference signal and receiving the reflection wherein analysing includes detecting a center of gravity of the extracted section of the cross correlated signal determining a time of the center of gravity, and determining the time of flight based on a time difference between the time of the center of gravity of the extracted section of the cross correlated signal and a first time at which the acoustic reference signal was emitted; and instructions for determining the distance between the mobile communications device and the object based on the determined time of flight and known characteristics of the acoustic reference signal.
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15. A mobile communications device including instructions fixed in a non-transitory tangible medium configured to determine a distance between the mobile communications device and an object, the non-transitory tangible medium comprising:
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instructions for emitting an acoustic reference signal from a speaker of the mobile communications device; instructions for receiving an acoustic input signal at a microphone of the mobile communications device, the acoustic input signal including a measurement portion including a reflection of the acoustic reference signal off the object; instructions for cross correlating at least the measurement portion with the emitted acoustic reference signal to provide a cross correlated signal; instructions for receiving estimated time of flight information relating to the object; instructions for extracting a section of the cross correlated signal corresponding to reflection of the acoustic reference signal by the object, based on the received estimated time of flight information; instructions for analyzing the extracted section of the cross correlated signal to determine a time of flight between emitting the acoustic reference signal and receiving the reflection, wherein analyzing includes detecting a center of gravity of the extracted section of the cross correlated signal, determining a time of the centre center of gravity, and determining the time of flight based on a time difference between the time of the center of gravity of the extracted section of the cross correlated signal and a first time at which the acoustic reference signal was emitted; and instructions for determining the distance between the mobile communications device and the object based on the determined time of flight and known characteristics of the acoustic reference signal.
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Specification