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US 10,855,973 B1Granted
Depth mapping using fringe interferometry
AssigneeFacebook Technologies, LLC
InventorsMichael Hall, Qing Chao
Life of this patent
Estimating the term…
Abstract
A depth camera assembly (DCA) determines distances between the DCA and objects in a local area within a field of view of the DCA. The DCA projects a series of sinusoidal patterns into the local area DCA and captures images of the sinusoidal patterns via a sensor. The DCA determines a distance between the DCA and locations in the local area based on a phase shift each of the sinusoidal patterns captured by each pixel of the sensor. Initially, a calibration offset is determined for each pixel of the sensor by emitting the sinusoidal patterns onto a target at a predetermined distance from the DCA and using phase shifts for a pixel and the predetermined distance to determine the pixel's calibration offset.
Claims15
An apparatus comprising:
- an illumination source configured to emit light comprising a series of different spatially periodic illumination patterns into a local area surrounding the illumination source, each different spatially periodic illumination pattern having a different specific spatial phase shift;
- an imaging device separated from the illumination source by a specific distance, the imaging device including a sensor comprising multiple pixels, the sensor configured to capture light from the spatially periodic illumination patterns, each pixel of the sensor configured to capture images including an intensity of light from the local area;
- and
- a processor coupled to the imaging device, the processor configured to receive an intensity of light captured by each of at least a set of the pixels of the sensor and configured to:
- identify a pixel of the sensor;
- determine an intensity of light from a location within the local area captured by the identified pixel in each of a set of images;
- determine a spatial phase shift of the light captured by the identified pixel based on the determined intensities;
- and
- determine a depth from the imaging device to the location within the local area from which the identified pixel captured light based on a difference between the determined spatial phase shift and a calibration offset for the identified pixel, as well as the specific distance between the illumination source and the imaging device and an angle between a line perpendicular to a plane including the illumination source and the location within the local area from which the identified pixel captures light, the calibration offset for the identified pixel corresponding to a frequency of a spatially periodic illumination pattern from which the imaging device captured light and previously stored in association with a location of the identified pixel in the sensor and with the frequency of the spatially periodic illumination pattern.
6 more elements
A system comprising:
- a headset including:
- an electronic display configured to present content to a user,
- an illumination source configured to emit light comprising a series of different spatially periodic illumination patterns into a local area surrounding the headset, each different spatially periodic illumination pattern having a different specific spatial phase shift;
- an imaging device separated from the illumination source by a specific distance, the imaging device including a sensor comprising multiple pixels, the sensor configured to capture light from the spatially periodic illumination patterns, each pixel of the sensor configured to capture images including an intensity of light from the local area;
- a processor coupled to the imaging device, the processor configured to receive an intensity of light captured by each of at least a set of the pixels of the sensor and configured to:
- identify a pixel of the sensor;
- determine an intensity of light from a location within the local area captured by the identified pixel in each of a set of images;
- determine a phase shift of the light captured by the identified pixel based on the determined intensities;
- and
- determine a depth from the imaging device to the location within the local area from which the identified pixel captured light based on a difference between the determined spatial phase shift and a calibration offset for the identified pixel, as well as the specific distance between the illumination source and the imaging device and an angle between a line perpendicular to a plane including the illumination source and the location within the local area from which the identified pixel captures light, the calibration offset for the identified pixel corresponding to a frequency of a spatially periodic illumination pattern from which the imaging device captured light and previously stored in association with a location of the identified pixel in the sensor and with the frequency of the spatially periodic illumination pattern;
- and
- a console coupled to the processor, the console configured to generate content based on the determined depths for each of at least the set of the pixels and to communicate the generated content to the electronic display included in the headset.
9 more elements
A method comprising:
- emitting a series of different spatially periodic illumination patterns from an illumination source into a local area surrounding the illumination source, each different spatially periodic illumination pattern having a different specific spatial phase shift;
- capturing light from the spatially periodic illumination patterns by an imaging device positioned a specific distance from the illumination source, the imaging device including a sensor comprising multiple pixels that are each configured to capture images including an intensity of light from the local area;
- identifying a pixel of the sensor of the imaging device;
- determining an intensity of light from a location within the local area captured by the identified pixel in each of a set of images;
- determining a spatial phase shift of the light captured by the identified pixel based on the determined intensities;
- obtaining a calibration offset for the identified pixel, the calibration offset for the identified pixel corresponding to a frequency of a spatially periodic illumination pattern from which the imaging device captured light and previously stored in association with a location of the identified pixel in the sensor and with the frequency of the spatially periodic illumination pattern;
- and
- determining a depth from the imaging device to the location within the local area from which the identified pixel captured light based on a difference between the determined spatial phase shift and the calibration offset for the identified pixel, as well as the specific distance between the illumination source and the imaging device and an angle between a line perpendicular to a plane including the illumination source and the location within the local area from which the identified pixel captures light.
5 more elements
Dependencies are inferred from the claim text.