Abstract: A near-eye display (NED) comprises an electronic display, an optical assembly, a scanning assembly, and a controller. The controller generates display instructions based in part on content. The display instructions describe a resolution within an adjustable range of resolutions and a frame rate within adjustable range of frame rates. The electronic display emits a plurality of light rays at the frame rate based on the display instructions. The scanning assembly shifts a direction of at least one of the plurality of light rays in accordance with the display instructions. The optical assembly controls a field of view at an eye box and directs the plurality of light rays including the at least one shifted light ray toward the eye box. The plurality of light rays form a virtual display that displays the content at the resolution and the frame rate.

Abstract: A light source may illuminate a scene that is obscured by fog. Light may reflect back to a time-resolved light sensor. For instance, the light sensor may comprise avalanche photodiodes that are not single-photon sensitive. The light sensor may perform a raster scan. The imaging system may determine reflectance and depth of the fog-obscured target. The imaging system may perform a probabilistic algorithm that exploits the fact that times of arrival of photons reflected from fog have a Gamma distribution that is different than the Gaussian distribution of times of arrival of photons reflected from the target. The imaging system may adjust frame rate locally depending on local density of fog, as indicated by a local Gamma distribution determined in a prior step. The imaging system may perform one or more of spatial regularization, temporal regularization, and deblurring.

Abstract: A sample may be illuminated in such a way that light passes through the sample, reflects from a set of reflectors, passes through the sample again and travels to a light sensor. The reflectors may be staggered in depth beneath the sample, each reflector being at a different depth. Light reflecting from each reflector, respectively, may arrive at the light sensor during a different time interval than that in which light reflecting from other reflectors arrives—or may have a different phase than that of light reflecting from the other reflectors. The light sensor may separately measure light reflecting from each reflector, respectively. The reflectors may be extremely small, and the separate reflections from the different reflectors may be combined in a super-resolved image. The super-resolved image may have a spatial resolution that is better than that indicated by the diffraction limit.

Abstract: A sample may be illuminated in such a way that light passes through the sample, reflects from a set of reflectors, passes through the sample again and travels to a light sensor. The reflectors may be staggered in depth beneath the sample, each reflector being at a different depth. Light reflecting from each reflector, respectively, may arrive at the light sensor during a different time interval than that in which light reflecting from other reflectors arrives—or may have a different phase than that of light reflecting from the other reflectors. The light sensor may separately measure light reflecting from each reflector, respectively. The reflectors may be extremely small, and the separate reflections from the different reflectors may be combined in a super-resolved image. The super-resolved image may have a spatial resolution that is better than that indicated by the diffraction limit.

Abstract: A pulsed laser may illuminate a scene that is obscured by dense, dynamic and heterogeneous fog. Light may reflect back to a time-resolved camera. Each pixel of the camera may detect a single photon during each frame. The imaging system may accurately determine reflectance and depth of the fog-obscured target, without any calibration or prior knowledge of the scene depth. The imaging system may perform a probabilistic algorithm that exploits the fact that times of arrival of photons reflected from fog have a Gamma distribution that is different than the Gaussian distribution of times of arrival of photons reflected from the target. The probabilistic algorithm may take into account times of arrival of all types of measured photons, including scattered and un-scattered photons.

Abstract: In one embodiment, a method includes detecting a proximity event associated with a first user and a second user, wherein the proximity event includes the second user being in geographic proximity to the first user and calculating an influence score associated with the proximity event, wherein the influence score is based at least in part on a social gravity of the second user and a duration of the proximity event. The method further includes, upon determining that the influence score is greater than a threshold score, identifying, based at least in part on a geographic location of the first user, a content object associated with the second user for provision to the first user and sending the content object to a client system associated with the first user for display.

Abstract: In one embodiment, a method includes receiving, from a sender node associated with a mesh network, a request to send a message to one or more recipient nodes, the wireless mesh network comprising a plurality of nodes, detecting a triggering condition associated with the wireless mesh network, predicting a routing path from the sender node to each of the one or more recipient nodes via the wireless mesh network through one or more relay nodes of the plurality of nodes based on proximity information and network information associated with the mesh network, and sending the message to the one or more recipient nodes via the one or more relay nodes of the wireless mesh network.

Abstract: In one embodiment, a method includes determining if notifications to be sent to user would benefit from being delivered by haptic stimulation under a current context. This determination may be made by accessing historical notification data of how the user previously responded to notifications in a similar context, and ranking conversion scores for each of one or more haptic-enabled delivery channels, wherein a conversion score indicates a probability of the user interacting with the notification. The most appropriate haptic message-delivery channel is selected based on the scores and historical data, and the notification is sent accordingly.

Abstract: In one embodiment, a method includes receiving a first location of a first client system of a first user and a second location of a second client system of a second user; determining that the first location and the second location are within a threshold proximity; accessing information associated with the first user and the second user to determine a first-user-specific context associated with the first user and a second-user-specific context associated with the second user; determining, based on the first location and the second location and further based on the first-user-specific context and the second-user-specific context, a potential mesh network for connecting the first client system to the second client system; and initiating an agent that is configured to send a communication prompt to the first client system for initiating a communication between the first client system and the second client system.

Abstract: A light source may illuminate a scene with amplitude-modulated light. The scene may include fluorescent material. The amplitude modulation may be periodic, and the frequency of the amplitude modulation may be swept. During the sweep, a time-of-flight sensor may take measurements of light returning from the scene. A computer may calculate, for each pixel in the sensor, a vector of complex numbers. Each complex number in the vector may encode phase and amplitude of light incident at the pixel and may correspond to measurements taken at a given frequency in the sweep. A computer may, based on phase of the complex numbers for a pixel, calculate fluorescence lifetime and scene depth of a scene point that corresponds to the pixel.

Abstract: In exemplary implementations of this invention, an aberrometer is used to measure the refractive condition of any eye. An artificial light source emits light that travels to a light sensor. Along the way, the light enters and then exits the eye, passes through or is reflected from one or more spatial light modulators (SLMs), and passes through an objective lens-system. The SLMs modify a bokeh effect of the imaging system (which is only visible when the system is out-of-focus), creating a blurred version of the SLM patterns. The light sensor then captures one or more out-of-focus images. If there are refractive aberrations in the eye, these aberrations cause the SLM patterns captured in the images to be distorted. By analyzing differences between the distorted captured patterns and the undistorted SLM patterns, refractive aberrations of the eye can be computed and an eyewear measurement generated.

Abstract: An imaging system images near-field objects with focused microwave or terahertz radiation. Multiple antennas emit microwave or terahertz radiation, such that the radiation varies in frequency over time, illuminates a near-field object, reflects from the near-field object, and travels to a passive aperture. For example, the passive aperture may comprise a dielectric lens or a parabolic reflector. The passive aperture focuses, onto a spatial region, the microwave or terahertz radiation that reflected from the near-field object. One or more antennas take measurements, in the spatial region, of the microwave or terahertz radiation that reflected from the near-field object. A computer calculates, based on the measurements, an image of the near-field object and depth information regarding the near-field object.

Abstract: A video camera captures images of retroreflection from the retina of an eye. These images are captured while the eye rotates. Thus, different images are captured in different rotational positions of the eye. A computer calculates, for each image, the eye's direction of gaze. In turn, the direction of gaze is used to calculate the precise location of a small region of the retina at which the retroflection occurs. A computer calculates a digital image of a portion of the retina by summing data from multiple retroreflection images. The digital image of the retina may be used for many practical applications, including medical diagnosis and biometric identification. In some scenarios, the video camera captures detailed images of the retina of a subject, while the subject is so far away that the rest of the subject's face is below the diffraction limit of the camera.

Abstract: A 3D imaging system uses a depth sensor to produce a coarse depth map, and then uses the coarse depth map as a constraint in order to correct ambiguous surface normals computed from polarization cues. The imaging system outputs an enhanced depth map that has a greater depth resolution than the coarse depth map. The enhanced depth map is also much more accurate than could be obtained from the depth sensor alone. In many cases, the imaging system extracts the polarization cues from three polarized images. Thus, in many implementations, the system takes only three extra images—in addition to data used to generate the coarse depth map—in order to dramatically enhance the coarse depth map.

Abstract: A 3D imaging system uses a depth sensor to produce a coarse depth map, and then uses the coarse depth map as a constraint in order to correct ambiguous surface normals computed from polarization cues. The imaging system outputs an enhanced depth map that has a greater depth resolution than the coarse depth map. The enhanced depth map is also much more accurate than could be obtained from the depth sensor alone. In many cases, the imaging system extracts the polarization cues from three polarized images. Thus, in many implementations, the system takes only three extra images—in addition to data used to generate the coarse depth map—in order to dramatically enhance the coarse depth map.

Abstract: A self-reset ADC may take a set of temporally equidistant, modulo samples of a bandlimited, analog signal, at a sampling rate that is greater than ?e samples per second, where ? is Archimedes' constant and is Euler's number. The bandlimited signal may have a bandwidth of 1 Hertz and a maximum frequency of 0.5 Hertz. These conditions of sampling rate, bandwidth and maximum frequency may ensure that an estimated signal may be recovered from the set of modulo samples. This estimated signal may be equal to the bandlimited signal plus a constant. The constant may be equal to an integer multiple of the modulus of the centered modulo operation employed to take the modulo samples.

Abstract: A time-of-flight imaging system may output light with a modulation frequency in the gigahertz band, to illuminate a range target. This high-frequency illumination may enable extremely precise—e.g., micron-scale—depth measurements. The system may modulate reflected light from the range target, to create a beat tone that has a frequency in the hertz band. In some cases, the modulated light in the gigahertz band is created by a first modulator and the beat tone in the hertz band is created by a second modulator. In some cases, the modulated light in the gigahertz band is created by an upshift cascade of modulators and the beat tone in the hertz band is created by a downshift cascade of modulators. A photodetector may measure the low-frequency beat tone. From this beat tone, phase of the signal and depth of the range target may be extracted.

Abstract: A video camera captures images of retroreflection from the retina of an eye. These images are captured while the eye rotates. Thus, different images are captured in different rotational positions of the eye. A computer calculates, for each image, the eye's direction of gaze. In turn, the direction of gaze is used to calculate the precise location of a small region of the retina at which the retroflection occurs. A computer calculates a digital image of a portion of the retina by summing data from multiple retroreflection images. The digital image of the retina may be used for many practical applications, including medical diagnosis and biometric identification. In some scenarios, the video camera captures detailed images of the retina of a subject, while the subject is so far away that the rest of the subject's face is below the diffraction limit of the camera.

Abstract: A sensor may measure light reflecting from a multi-layered object at different times. A digital time-domain signal may encode the measurements. Peaks in the signal may be identified. Each identified peak may correspond to a layer in the object. For each identified peak, a short time window may be selected, such that the time window includes a time at which the identified peak occurs. A discrete Fourier transform of that window of the signal may be computed. A frequency frame may be computed for each frequency in a set of frequencies in the transform. Kurtosis for each frequency frame may be computed. A set of high kurtosis frequency frames may be averaged, on a pixel-by-pixel basis, to produce a frequency image. Text characters that are printed on a layer of the object may be recognized in the frequency image, even though the layer is occluded.

Abstract: In some implementations, scene depth is extracted from dual frequency of a cross-correlation signal. A camera may illuminate a scene with amplitude-modulated light, sweeping the modulation frequency. For each modulation frequency in the sweep, each camera pixel may measure a cross-correlation of incident light and of a reference electrical signal. Each pixel may output a vector of cross-correlation measurements acquired by the pixel during a sweep. A computer may perform an FFT on this vector, identify a dual frequency at the second largest peak in the resulting power spectrum, and calculate scene depth as equal to a fraction, where the numerator is the speed of light times this dual frequency and the denominator is four times pi. In some cases, the two signals being cross-correlated have the same phase as each other during each cross-correlation measurement.