Arrangement and method for obtaining information using phase difference of modulated illumination
View Patent ↗Land-based vehicle including an arrangement for monitoring objects in or about a vehicle includes a source from which modulated illumination is emitted into an area in or about the vehicle, a receiver arranged to receive illumination reflected from an object in the path of the modulated illumination, and circuitry coupled to the receiver and the source and arranged to compare a phase of the modulated illumination with a phase of the reflected radiation at a common frequency to determine whether there is a phase difference between the modulated illumination and the reflected illumination. The phase difference is a measure of a property of the object, such as the distance between the object and the source/receiver, which can be co-located. Otherwise, if the source and receiver and not co-located or substantially co-located, the distance is a measure of the distance of travel of the illumination.
1. A vehicle including an arrangement for monitoring objects in or about a vehicle, comprising:
an infrared source from which modulated infrared illumination is emitted into an area in or about the vehicle;
a receiver arranged to receive infrared illumination reflected from an object in a path of the modulated illumination; and
circuitry coupled to said receiver and said source and arranged to compare a phase of the emitted modulated illumination with a phase of the received illumination at a common frequency to determine a phase difference between the modulated illumination and the reflected illumination,
said circuitry being arranged to obtain three-dimensional information about the object from the determined phase difference and monitor movement of the object based on data obtained from the three-dimensional information.
2. The vehicle of claim 1 , wherein said phase difference is a measure of distance between the object or a part thereof and said receiver and said source, and the three-dimensional information is a three-dimensional model.
3. The vehicle of claim 1 , wherein said circuitry is arranged to use a pattern recognition algorithm embodied on computer-readable medium to identify the object from the determined phase difference.
4. The vehicle of claim 1 , wherein said source is a modulated laser.
5. The vehicle of claim 1 , wherein said source is arranged such that the modulated illumination is directed into a compartment of the vehicle such that objects in the compartment in the vehicle are monitored.
6. The vehicle of claim 1 , wherein said source and said receiver are co-located.
7. The vehicle of claim 1 , further comprising an occupant protection device arranged to protect an occupant of the vehicle in the event of a crash involving the vehicle, said occupant protection device being coupled to said circuitry and being controlled based on the monitored movement of the object.
8. The vehicle of claim 7 , wherein said phase difference is a measure of distance between the object or a part thereof and said receiver and said source, said occupant protection device being controlled based on the distance between the object or a part thereof and said receiver and said source.
9. The vehicle of claim 8 , wherein said circuitry is arranged to determine a velocity of the object using multiple determinations of the distance and time differences, said occupant protection device being at least partially controlled based on the velocity of the object.
10. The vehicle of claim 1 , wherein said source is arranged to emit modulated illumination having a wavelength greater than 1.4 microns.
11. A method for monitoring objects in or about a vehicle, comprising:
arranging an infrared illumination source on the vehicle;
emitting modulated illumination from the infrared source into an area in or about the vehicle;
receiving illumination reflected from an object in a path of the emitted modulated illumination at a location on the vehicle;
comparing a phase of the modulated illumination with a phase of the reflected radiation at a common frequency to determine a phase difference between the modulated illumination and the reflected illumination;
obtaining three-dimensional information about the object from the determined phase difference; and
monitoring movement of the object based on data obtained from the three-dimensional information.
12. The method of claim 11 , wherein the phase difference is a measure of distance between the object or a part thereof and the location on the vehicle from which the illumination is emitted and at which the reflected illumination is received.
13. The method of claim 11 , wherein the infrared illumination source is arranged to emit the modulated illumination into a compartment of the vehicle such that objects in the compartment in the vehicle are monitored.
14. The method of claim 13 , further comprising co-locating the source and a receiver at which the reflected illumination is received.
15. The method of claim 11 , further comprising at least partially controlling an occupant protection device which protects an occupant of the vehicle in the event of a crash involving the vehicle based on the monitored movement of the object.
16. The method of claim 15 , wherein the phase difference is a measure of distance between the object or a part thereof and the location on the vehicle from which the illumination is emitted and at which the reflected illumination is received, the occupant protection device being controlled based on the distance between the object or a part thereof and the location on the vehicle from which the illumination is emitted and at which the reflected illumination is received.
17. The method of claim 16 , further comprising:
determining a velocity of the object using multiple determinations of the distance and time differences; and
controlling the occupant protection device based at least in part on the velocity of the object.
18. The method of claim 11 , wherein the emitted illumination has a wavelength greater than 1.4 microns.
19. A method for controlling an occupant protection device in a vehicle which protects an occupant of the vehicle in the event of a crash involving the vehicle, comprising:
arranging an infrared illumination source on the vehicle;
emitting modulated illumination from the infrared source into an area in or about the vehicle;
receiving illumination reflected from an object in a path of the emitted modulated illumination at a location on the vehicle;
comparing a phase of the modulated illumination with a phase of the reflected radiation at a common frequency to determine a phase difference between the emitted modulated illumination and the reflected illumination;
deriving a distance between the object or a part thereof and a location on the vehicle from which the modulated illumination is emitted and at which the reflected illumination is received;
obtaining three-dimensional information about the object from the determined phase difference;
monitoring movement of the object based on data obtained from the three-dimensional information; and
controlling the occupant protection device based at least in part on the derived distance and the monitored movement of the object.
20. The method of claim 19 , wherein the infrared illumination source is arranged to emit the modulated illumination into a compartment of the vehicle such that objects in the compartment in the vehicle are monitored.
21. The method of claim 20 , further comprising co-locating the source and a receiver at which the reflected illumination is received.
22. The method of claim 19 , further comprising:
determining a velocity of the object using multiple derivations of the distance and time differences; and
controlling the occupant protection device based at least in part on the velocity of the object.
23. The method of claim 19 , wherein the emitted illumination has a wavelength greater than 1.4 microns.