Abstract: A system for dark current compensation in SPAD imagery is configurable to capture an image frame with the SPAD array and generate a temporally filtered image by performing a temporal filtering operation using the image frame and at least one preceding image frame. The at least one preceding image frame is captured by the SPAD array at a timepoint that temporally precedes a timepoint associated with the image frame. The system is also configurable to obtain a dark current image frame. The dark current image frame includes data indicating one or more SPAD pixels of the plurality of SPAD pixels that detect an avalanche event without detecting a corresponding photon. The system is also configurable to generate a dark current compensated image by performing a subtraction operation on the temporally filtered image or the image frame based on the dark current image frame.

Abstract: Techniques for evaluating multiple images, which originate from multiple different sources, and for selecting specific images to generate an overlaid image are disclosed. A first set of system camera images (e.g., based on a first FPS rate) and a second set of external camera images (e.g., based on a second FPS rate) are obtained. A set of rules are accessed in order to govern a selection process for selecting a specific system camera image and a specific external camera image. The selected images are designated for use in generating an overlaid image. The selection process is performed using the accessed set of rules. The overlaid image is generated by overlaying and aligning content obtained from the selected images.

Abstract: Techniques for generating a high resolution full color output image from lower resolution sparse color input images are disclosed. A camera generates images. The camera's sensor has a sparse Bayer pattern. While the camera is generating the images, IMU data for each image is acquired. The IMU data indicates a corresponding pose the camera was in while the camera generated each image. The images and IMU data are fed into a motion model, which performs temporal filtering on the images and uses the IMU data to generate a red-only image, a green-only image, a blue-only image, and a monochrome image. The color images are up-sampled to match the resolution of the monochrome image. A high resolution output color image is generated by combining the up-sampled images and the monochrome image.

Abstract: Disclosed herein are techniques for providing an illumination system that emits illumination into an environment while also enabling that system to be undetectable to certain types of external light detection systems. The system includes a single photon avalanche diode (SPAD) low light (LL) detection device and a light emitting device. The light emitting device provides illumination having a wavelength of at least 950 nanometers (nm). An intensity of the illumination is set to a level that causes the illumination to be undetectable from a determined distance away based on the roll off rate of the light. While the light emitting device is providing the illumination, the SPAD LL detection device generates an image of an environment in which the illumination is being provided.

Abstract: A system for updating continuous image alignment of separate cameras identifies a previous alignment matrix associated with a previous frame pair captured at one or more previous timepoints by a reference camera and a match camera. The previous alignment matrix is based on visual correspondences in the previous frame pair. The system also identifies a current matrix associated with a current frame pair captured at one or more current timepoints by the reference camera and the match camera. The current matrix is based on visual correspondences in the current frame pair. The system also identifies a difference value associated with the reference camera or the match camera relative to the one or more previous timepoints and the one or more current timepoints. The system also generates an updated alignment matrix by using the previous alignment matrix, the current matrix, and the difference value as inputs.

Abstract: A system for selectively modifying gating rate in a single photon avalanche diode (SPAD) is configurable to access first frame metadata associated with a first image frame. The first image frame is captured by performing a first plurality of gate operations to configure the SPAD array to enable photon detection over a frame capture time period. The first plurality of gate operations is performed at a first gating rate such that the first plurality of gate operations comprises a first quantity of gate operations performed over the frame capture time period. The system is further configurable to define a second gating rate based on the first frame metadata and capture a second image frame by performing a second plurality of gate operations to configure the SPAD array to enable photon detection at the second gating rate.

Abstract: Modifications are performed to cause a style of an image to match a different style. A first image is accessed, where the first image has the first style. A second image is also accessed, where the second image has a second style. Subsequent to a deep neural network (DNN) learning these styles, a copy of the first image is fed as input to the DNN. The DNN modifies the first image copy by transitioning the first image copy from being of the first style to subsequently being of the second style. As a consequence, a modified style of the transitioned first image copy bilaterally matches the second style.

Abstract: A system for power efficient image acquisition is configurable to capture, using an image sensor, a plurality of partial image frames including at least a first partial image frame and a second partial image frame. The first partial image frame is captured at a first timepoint using a first subset of image sensing pixels of the plurality of image sensing pixels of the image sensor. The second partial image frame is captured at a second timepoint using a second subset of image sensing pixels of the plurality of image sensing pixels of the image sensor. The second subset of image sensing pixels includes different image sensing pixels than the first subset of image sensing pixels, and the second timepoint is temporally subsequent to the first timepoint. The system is configurable to generate a composite image frame based on the plurality of partial image frames.

Abstract: An HMD includes a single photon avalanche diode (SPAD) array comprising a plurality of SPAD pixels. The HMD also includes a display positioned to display images for viewing by an eye of a user. The HMD also includes one or more processors and one or more hardware storage devices storing instructions that are executable by the one or more processors to configure the HMD to perform various acts associated with using the SPAD array to capture an image frame of an environment for display to the user.

Abstract: Techniques for aligning images generated by an integrated camera physically mounted to an HMD with images generated by a detached camera physically unmounted from the HMD are disclosed. A 3D feature map is generated and shared with the detached camera. Both the integrated camera and the detached camera use the 3D feature map to relocalize themselves and to determine their respective 6 DOF poses. The HMD receives the detached camera's image of the environment and the 6 DOF pose of the detached camera. A depth map of the environment is accessed. An overlaid image is generated by reprojecting a perspective of the detached camera's image to align with a perspective of the integrated camera and by overlaying the reprojected detached camera's image onto the integrated camera's image.

Abstract: Techniques for evaluating multiple images, which originate from multiple different sources, and for selecting specific images to generate an overlaid image are disclosed. A first set of system camera images (e.g., based on a first FPS rate) and a second set of external camera images (e.g., based on a second FPS rate) are obtained. A set of rules are accessed in order to govern a selection process for selecting a specific system camera image and a specific external camera image. The selected images are designated for use in generating an overlaid image. The selection process is performed using the accessed set of rules. The overlaid image is generated by overlaying and aligning content obtained from the selected images.

Abstract: Disclosed herein are techniques for providing an illumination system that emits illumination into an environment while also enabling that system to be undetectable to certain types of external light detection systems. The system includes a single photon avalanche diode (SPAD) low light (LL) detection device and a light emitting device. The light emitting device provides illumination having a wavelength of at least 950 nanometers (nm). An intensity of the illumination is set to a level that causes the illumination to be undetectable from a determined distance away based on the roll off rate of the light. While the light emitting device is providing the illumination, the SPAD LL detection device generates an image of an environment in which the illumination is being provided.

Abstract: Techniques for generating a high resolution full color output image from lower resolution sparse color input images are disclosed. A camera generates images. The camera's sensor has a sparse Bayer pattern. While the camera is generating the images, IMU data for each image is acquired. The IMU data indicates a corresponding pose the camera was in while the camera generated each image. The images and IMU data are fed into a motion model, which performs temporal filtering on the images and uses the IMU data to generate a red-only image, a green-only image, a blue-only image, and a monochrome image. The color images are up-sampled to match the resolution of the monochrome image. A high resolution output color image is generated by combining the up-sampled images and the monochrome image.

Abstract: A system for dark current compensation in SPAD imagery is configurable to capture an image frame with the SPAD array and generate a temporally filtered image by performing a temporal filtering operation using the image frame and at least one preceding image frame. The at least one preceding image frame is captured by the SPAD array at a timepoint that temporally precedes a timepoint associated with the image frame. The system is also configurable to obtain a dark current image frame. The dark current image frame includes data indicating one or more SPAD pixels of the plurality of SPAD pixels that detect an avalanche event without detecting a corresponding photon. The system is also configurable to generate a dark current compensated image by performing a subtraction operation on the temporally filtered image or the image frame based on the dark current image frame.

Abstract: Improved techniques for re-localizing Internet-of-Things (IOT) devices are disclosed herein. Sensor data digitally representing one or more condition(s) monitored by an IOT device is received. In response, a sensor readings map is accessed, where this map is associated with the IOT device. The map also digitally represents the IOT device's environment and includes data representative of a location of the IOT device within the environment. The map also includes data representative of the conditions monitored by the IOT device. Additionally, the map is updated by attaching the sensor data to the map. In some cases, a coverage map can also be computed. Both the sensors readings map and the coverage map can be automatically updated in response to the IOT device being re-localized.

Abstract: Techniques for correcting an overlay misalignment between an external camera image and a system camera image are disclosed. A first system camera image and a first external camera image are acquired. A first visual alignment is performed between those two images to produce an overlaid image. Some of the content in the overlaid image is surrounded by a bounding element. A position of the bounding element is modified based on movements of the system camera and/or the external camera. In response to performing a second visual alignment using new images, an update vector is computed. Relative movement between the two cameras is determined. Based on the movement and based on the update vector, the bounding element is progressively transitioned to a corrected position in the overlaid image. A speed by which the bounding element is progressively transitioned is proportional to the amount of movement.

Abstract: A system for adding persistence to SPAD imagery is configurable to capture, using a SPAD array, a plurality of image frames. The system is configurable to capture, using an IMU, pose data associated with the plurality of image frames. The pose data includes at least respective pose data associated with each of the plurality of image frames. The system is configurable to determine a persistence term based on the pose data. The system is also configurable to generate a composite image based on the plurality of image frames, the respective pose data associated with each of the plurality of image frames, and the persistence term. The persistence term defines a contribution of each of the plurality of image frames to the composite image.

Abstract: Techniques for aligning images generated by two cameras are disclosed. This alignment is performed by computing a relative 3D orientation between the two cameras. A first gravity vector for a first camera and a second gravity vector for a second camera are determined. A first camera image is obtained from the first camera, and a second camera image is obtained from the second camera. A first alignment process is performed to partially align the first camera's orientation with the second camera's orientation. This process is performed by aligning the gravity vectors, thereby resulting in two degrees of freedom of the relative 3D orientation being eliminated. Visual correspondences between the two images are identified. A second alignment process is performed to fully align the orientations. This process is performed by using the identified visual correspondences to identify and eliminate a third degree of freedom of the relative 3D orientation.

Abstract: Techniques for aligning images generated by an integrated camera physically mounted to an HMD with images generated by a detached camera physically unmounted from the HMD are disclosed. A 3D feature map is generated and shared with the detached camera. Both the integrated camera and the detached camera use the 3D feature map to relocalize themselves and to determine their respective 6 DOF poses. The HMD receives the detached camera's image of the environment and the 6 DOF pose of the detached camera. A depth map of the environment is accessed. An overlaid image is generated by reprojecting a perspective of the detached camera's image to align with a perspective of the integrated camera and by overlaying the reprojected detached camera's image onto the integrated camera's image.

Abstract: A system for generating depth information from low-resolution images is configured to access a plurality of image frames capturing an environment, identify a first group of image frames from the plurality of image frames, and generate a first image comprising a first composite image of the environment using the first group of image frames as input. The first composite image has an image resolution that is higher than an image resolution of the image frames of the first group of image frames. The system is also configured to obtain a second image of the environment, where parallax exists between a capture perspective associated with the first image and a capture perspective associated with the second image. The system is also configured to generate depth information for the environment based on the first image and the second image.