Abstract: A system for modifying a dark current image is configurable to receive an input image depicting a dark current state for one or more pixels of the input image, The dark current state for one or more pixels of the input image comprises one of: a faulty state or a non-faulty state. The system is configurable to partition the input image into a plurality of partitions and generate an updated input image by imposing at least one quantity constraint or at least one severity constraint to the plurality of partitions in association with at least one type of dark current state.

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: 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 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: Techniques for updating a position of overlaid image content using IMU data to reflect subsequent changes in camera positions to minimize latency effects are disclosed. A “system camera” refers to an integrated camera that is a part of an HMD. An “external camera” is a camera that is separated from the HMD. The system camera and the external camera generate images. These images are overlaid on one another and aligned to form an overlaid image. Content from the external camera image is surrounded by a bounding element in the overlaid image. IMU data associated with both the system camera and the external camera is obtained. Based on that IMU data, an amount of movement that the system camera and/or the external camera have moved since the images were originally generated is determined. Based on that movement, the bounding element is shifted to a new position in the overlaid image.

Abstract: An image sensor configured to capture imagery with mitigated noise includes a plurality of image sensing pixels arranged to form a sensor array. Each image sensing pixel of the plurality of image sensing pixels comprises an active area configured to receive photons to facilitate image capture. Each active area comprises a length and a width. For at least one image sensing pixel of the plurality of image sensing pixels, the length or the width of the active area is smaller than about 80% of a pixel pitch measurement between the at least one image sensing pixel and an adjacent image sensing pixel. A size of the active area relative to the pixel pitch measurement contributes to mitigating sensor noise for the image sensor.

Abstract: Techniques to temporally filter images via a filtering weight computation are disclosed. A first image having a first timestamp and a second image having a second timestamp are acquired. These images are generated by a camera, and the first timestamp is before the second timestamp. A motion compensation (MC) operation is performed on the first image to produce an MC image. A difference image is generated using the MC image and the second image. The difference image reflects differences in intensities that exist between the two images. A local weight map is generated based on those differences. A global weight map is generated based on certain IMU data. A final weight map is generated based on a combination of the local weight map and the global weight map. The final weight map is used to generate a filtered 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: Techniques for generating a fused enhanced image. A first image is generated using a first camera of a first modality, and a second image is generated using a second camera of a second modality. Pixels that are common between the two images are identified. Textures for the common pixels are determined. A camera characteristic, which is linked to noise, is identified. A scaling factor is applied to the textures in the first image. A first saliency is determined using the scaled textures. A second saliency is determined using the textures from the second image. An alpha map is generated and reflects edge detection weights that have been computed for each one of the common pixels based on the two saliencies. Based on the alpha map, textures are merged from the common pixels to generate the fused enhanced image.

Abstract: Techniques for generating a temporally filtered image designed to compensate for global motions of a camera and to compensate for local motions of an object are disclosed. A history frame and a current frame are acquired. A global motion compensation operation is performed on the history frame to reproject a pose of the history frame to match the pose of the current frame. The history frame is compared against the current frame to identify pixels that represent moving objects. For each of those pixels, an optical flow vector is computed. The optical flow vectors are then applied to those pixels to shift those pixels to new locations. These new positions, which are in the history frame, correspond to positions that were identified in the current frame. Afterwards, the current frame is temporally filtered with the history frame.

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 image content are disclosed. The alignment occurs by concurrently identifying corner and line features and by aligning the images based on those features. As a result, relaxed constraints can be used during the alignment process as compared to constraints that are required when aligning images using only corner features. To achieve these benefits, first and second images are acquired. A first set of pixels that correspond to corner features are detected within the images. In parallel, a second set of pixels that correspond to line features are detected within the images. Image content is then aligned from the two images. The aligning process is performed using at least some of the pixels from the first and second sets.

Abstract: A system for obtaining color imagery using SPADs includes a SPAD array that has a plurality of SPAD pixels. Each of the plurality of SPAD pixels includes a respective color filter positioned thereover. The system is configurable to capture an image frame using the SPAD array and generate a 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, after performing the temporal filtering operation, generate a color image by demosaicing the filtered image.

Abstract: A system for facilitating intensity image capture and time of flight capture. The system includes an image sensor array comprising a plurality of image sensor pixels, 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 system to facilitate intensity image capture and time of flight capture by configuring the system to perform interleaved intensity image capture and time of flight capture operations using the image sensor array.

Abstract: A system for generating high-resolution video from low-resolution images is configured to access a first video stream and a second video stream capturing an environment. The first video stream is captured by a first video capture device. The second video stream is captured by a second video capture device. Image frames of the first video stream are temporally synchronized with corresponding image frames of the second video stream. The system is also configured to generate a composite video stream with a higher resolution than the first or second video streams. Each composite image frame of the composite video stream is generated using a respective image frame of the first video stream and a temporally synchronized corresponding image frame of the second video stream as input.

Abstract: A computing system includes an illumination light source configured to emit illumination light into an external environment and an orientation sensor configured to estimate an orientation of the illumination light source relative to the external environment. The computing system includes a logic subsystem and a storage subsystem holding instructions executable by the logic subsystem to define a light restriction zone within the external environment. Based at least in part on the orientation of the illumination light source, the illumination light source is dynamically controlled to direct the illumination light toward at least a portion of the external environment outside the light restriction zone, while mitigating emission of the illumination light into the light restriction zone.

Abstract: A system for structured light depth computation using single photon avalanche diodes (SPADs) is configurable to, over a frame capture time period, selectively activate the illuminator to perform interleaved structured light illumination operations. The interleaved structured light illumination operations comprise alternately emitting at least a first structured light pattern from the illuminator and emitting at least a second structured light pattern from the illuminator. The system is also configurable to, over the frame capture time period, perform a plurality of sequential shutter operations to configure each SPAD pixel of the SPAD array to enable photon detection. The plurality of sequential shutter operations generates, for each SPAD pixel of the SPAD array, a plurality of binary counts indicating whether a photon was detected during each of the plurality of sequential shutter operations.

Abstract: Examples are disclosed that relate to providing image data to a user in a defined space of a surrounding environment from a perspective of the user. One example provides a computing system, comprising a logic subsystem, and a storage subsystem comprising instructions executable by the logic subsystem to obtain information regarding a pose of a user within a defined space, based upon the pose of the user, determine a portion of an environment surrounding the defined space toward which the user is looking, obtain image data representing the portion of the environment from a perspective of the user, and provide the image data for display via a display device within the defined space.

Abstract: Techniques for generating an enhanced image. A first image is generated using a camera of a first modality, and a second image is generated using a camera of a second modality. Pixels that are common between the two images are identified. An alpha map is generated. The alpha map reflects edge detection weights that are computed for the common pixels based on saliency values. A determination is made as to how much texture from the images to use to generate an enhanced image. This determination is based on the edge detection weights included within the alpha map. Based on the edge detection weights, textures are merged from the common pixels to generate the enhanced image. Color is also added to the enhanced image, where the color reflects an additional property (e.g., the texture source for the pixel) that is associated with one or both of the images.