Abstract: A mobile device determines a vision based pose using images captured by a camera and determines a sensor based pose using data from inertial sensors, such as accelerometers and gyroscopes. The vision based pose and sensor based pose are used separately in a visualization application, which displays separate graphics for the different poses. For example, the visualization application may be used to calibrate the inertial sensors, where the visualization application displays a graphic based on the vision based pose and a graphic based on the sensor based pose and prompts a user to move the mobile device in a specific direction with the displayed graphics to accelerate convergence of the calibration of the inertial sensors. Alternatively, the visualization application may be a motion based game or a photography application that displays separate graphics using the vision based pose and the sensor based pose.

Abstract: A first map comprising local features and 3D locations of the local features is generated, the local features comprising visible features in a current image and a corresponding set of covisible features. A second map comprising prior features and 3D locations of the prior features may be determined, where each prior feature: was first imaged at a time prior to the first imaging of any of the local features, and lies within a threshold distance of at least one local feature. A first subset comprising previously imaged local features in the first map and a corresponding second subset of the prior features in the second map is determined by comparing the first and second maps, where each local feature in the first subset corresponds to a distinct prior feature in the second subset. A transformation mapping a subset of local features to a subset of prior features is determined.

Abstract: Embodiments disclosed pertain to the use of user equipment (UE) for the generation of a 3D exterior envelope of a structure based on captured images and a measurement set associated with each captured image. In some embodiments, a sequence of exterior images of a structure is captured and a corresponding measurement set comprising Inertial Measurement Unit (IMU) measurements, wireless measurements (including Global Navigation Satellite (GNSS) measurements) and/or other non-wireless sensor measurements may be obtained concurrently. A closed-loop trajectory of the UE in global coordinates may be determined and a 3D structural envelope of the structure may be obtained based on the closed loop trajectory and feature points in a subset of images selected from the sequence of exterior images of the structure.

Abstract: A first map comprising local features and 3D locations of the local features is generated, the local features comprising visible features in a current image and a corresponding set of covisible features. A second map comprising prior features and 3D locations of the prior features may be determined, where each prior feature: was first imaged at a time prior to the first imaging of any of the local features, and lies within a threshold distance of at least one local feature. A first subset comprising previously imaged local features in the first map and a corresponding second subset of the prior features in the second map is determined by comparing the first and second maps, where each local feature in the first subset corresponds to a distinct prior feature in the second subset. A transformation mapping a subset of local features to a subset of prior features is determined.

Abstract: An accelerometer in a mobile device is calibrated by taking multiple measurements of acceleration vectors when the mobile device is held stationary at different orientations with respect to a plane normal. A circle is calculated that fits respective tips of measured acceleration vectors in the accelerometer coordinate system. The radius of the circle and the lengths of the measured acceleration vectors are used to calculate a rotation angle for aligning the accelerometer coordinate system with the mobile device surface. A gyroscope in the mobile device is calibrated by taking multiple measurements of a rotation axis when the mobile device is rotated at different rates with respect to the rotation axis. A line is calculated that fits the measurements. The angle between the line and an axis of the gyroscope coordinate system is used to align the gyroscope coordinate system with the mobile device surface.

Abstract: Techniques for multiplexing and transmitting multiple data streams are described. Transmission of the multiple data streams occurs in “super-frames”. Each super-frame has a predetermined time duration and is further divided into multiple (e.g., four) frames. Each data block for each data stream is outer encoded to generate a corresponding code block. Each code block is partitioned into multiple subblocks, and each data packet in each code block is inner encoded and modulated to generate modulation symbols for the packet. The multiple subblocks for each code block are transmitted in the multiple frames of the same super-frame, one subblock per frame. Each data stream is allocated a number of transmission units in each super-frame and is assigned specific transmission units to achieve efficient packing. A wireless device can select and receive individual data streams.

Abstract: Methods, systems, computer-readable media, and apparatuses for fast cost aggregation for dense stereo matching are presented. One example method includes the steps of receiving first and second images of a scene; rectifying the images; computing a cost volume based on the first and second images; subsampling the cost volume to generate a subsampled cost volume; for each pixel, p, in the subsampled cost volume, determining one or more local extrema in the subsampled cost volume for each neighboring pixel, q, within a window centered on the pixel, p; for each pixel, p, performing cost aggregation using the one or more local extrema; performing cross checking to identify matching pixels; and responsive to identifying unmatched pixels, performing gap-filling for the unmatched pixels to generate a disparity map; and generate and storing a depth map from the disparity map.

Abstract: Methods, systems, computer-readable media, and apparatuses for fast cost aggregation for dense stereo matching are presented. One example method includes the steps of receiving first and second images of a scene; rectifying the images; computing a cost volume based on the first and second images; subsampling the cost volume to generate a subsampled cost volume; for each pixel, p, in the subsampled cost volume, determining one or more local extrema in the subsampled cost volume for each neighboring pixel, q, within a window centered on the pixel, p; for each pixel, p, performing cost aggregation using the one or more local extrema; performing cross checking to identify matching pixels; and responsive to identifying unmatched pixels, performing gap-filling for the unmatched pixels to generate a disparity map; and generate and storing a depth map from the disparity map.

Abstract: Embodiments disclosed pertain to the use of user equipment (UE) for the generation of a 3D exterior envelope of a structure based on captured images and a measurement set associated with each captured image. In some embodiments, a sequence of exterior images of a structure is captured and a corresponding measurement set comprising Inertial Measurement Unit (IMU) measurements, wireless measurements (including Global Navigation Satellite (GNSS) measurements) and/or other non-wireless sensor measurements may be obtained concurrently. A closed-loop trajectory of the UE in global coordinates may be determined and a 3D structural envelope of the structure may be obtained based on the closed loop trajectory and feature points in a subset of images selected from the sequence of exterior images of the structure.

Abstract: Embodiments disclosed pertain to the use of user equipment (UE) for the generation of a 3D exterior envelope of a structure based on captured images and a measurement set associated with each captured image. In some embodiments, a sequence of exterior images of a structure is captured and a corresponding measurement set comprising Inertial Measurement Unit (IMU) measurements, wireless measurements (including Global Navigation Satellite (GNSS) measurements) and/or other non-wireless sensor measurements may be obtained concurrently. A closed-loop trajectory of the UE in global coordinates may be determined and a 3D structural envelope of the structure may be obtained based on the closed loop trajectory and feature points in a subset of images selected from the sequence of exterior images of the structure.

Abstract: Embodiments disclosed obtain a plurality of measurement sets from a plurality of sensors in conjunction with the capture of a sequence of exterior and interior images of a structure while traversing locations in and around the structure. Each measurement set may be associated with at least one image. An external structural envelope of the structure is determined from exterior images of the structure and the corresponding outdoor trajectory of a UE. The position and orientation of the structure and the structural envelope is determined in absolute coordinates. Further, an indoor map of the structure in absolute coordinates may be obtained based on interior images of the structure, a structural envelope in absolute coordinates, and measurements associated with the indoor trajectory of the UE during traversal of the indoor area to capture the interior images.

Abstract: A system and method for frequency diversity uses interleaving in a wireless communication system utilizing orthogonal frequency division multiplexing (OFDM) with various FFT sizes. Subcarriers of one or more interlaces are interleaved in a bit reversal fashion and the one or more interlaces are interleaved.

Abstract: A system and method is described herein for solving for surface normals of objects in the scene observed in a video stream. The system and method may include sampling the video stream to generate a set of keyframes; generating hypothesis surface normals for a set of mappoints in each of the keyframes; warping patches of corresponding mappoints in a first keyframe to the viewpoint of a second keyframe with a warping matrix computed from each of the hypothesis surface normals; scoring warping errors between each hypothesis surface normal in the two keyframes; and discarding hypothesis surface normals with high warping errors between the first and second keyframes.

Abstract: A system and method for frequency diversity uses interleaving in a wireless communication system utilizing orthogonal frequency division multiplexing (OFDM) with various FFT sizes. Subcarriers of one or more interlaces are interleaved in a bit reversal fashion and the one or more interlaces are interleaved in the bit reversal fashion.

Abstract: A system for storing target images for object recognition predicts a querying performance for the target image if the target image were included in a search tree of a database. The search tree has a universal search tree structure that is fixed so that it does not change with the addition of new target images. The target image is selected for inclusion or exclusion in the search tree based on the based on the querying performance, wherein the fixed tree structure of the search tree does not change if inclusion of the target image is selected.

Abstract: A reference in an unknown environment is generated on the fly for positioning and tracking. The reference is produced in a top down process by capturing an image of a planar object with a predefined geometric shape, detecting edge pixels of the planar object, then detecting a plurality of line segments from the edge pixels. The plurality of line segments may then be used to detect the planar object in the image based on the predefined geometric shape. An initial pose of the camera with respect to the planar object is determined and tracked using the edges of the planar object.

Abstract: Systems, apparatus and methods for estimating gravity and/or scale in a mobile device are presented. A difference between an image-based pose and an inertia-based pose is using to update the estimations of gravity and/or scale. The image-based pose is computed from two poses and is scaled with the estimation of scale prior to the difference. The inertia-based pose is computed from accelerometer measurements, which are adjusted by the estimation for gravity.

Abstract: A mobile device tracks a relative pose between a camera and a target using Vision aided Inertial Navigation System (VINS), that includes a contribution from inertial sensor measurements and a contribution from vision based measurements. When the mobile device detects movement of the target, the contribution from the inertial sensor measurements to track the relative pose between the camera and the target is reduced or eliminated. Movement of the target may be detected by comparing vision only measurements from captured images and inertia based measurements to determine if a discrepancy exists indicating that the target has moved. Additionally or alternatively, movement of the target may be detected using projections of feature vectors extracted from captured images.

Abstract: A mobile device compensates for a lack of a time stamp when an image frame is captured by estimating the frame time stamp latency. The mobile device captures images frames and time stamps each frame after the frame time stamp latency. A vision based rotation is determined from a pair of frames. A plurality of inertia based rotations is measured using time stamped signals from an inertial sensor in the mobile device based on different possible delays between time stamping each frame and time stamps on the signals from the inertial sensors. The determined rotations may be about the camera's optical axis. The vision based rotation is compared to the plurality of inertia based rotations to determine an estimated frame time stamp latency, which is used to correct the frame time stamp latency when time stamping subsequently captured frames. A median latency determined using different frame pairs may be used.

Abstract: In several aspects, an electronic device and method index a repository of N documents by W words, by not storing between queries, N*W numbers that are specific to each word i and each document j, normally used to compute a score of relevance to a query, of each document j. Instead, the electronic device and method generate the N*W word-specific -document-specific numbers dynamically at query time, based on a set of W numbers corresponding to the W words, and one or more sets (e.g. x sets) of N numbers corresponding to the N documents. Query-time generation of word-specific-document-specific numbers reduces memory otherwise required, e.g. to store these numbers. Hence, in certain aspects W+xN numbers are maintained between queries, and these numbers are changed incrementally when a new document is added to the set or an existing document is removed. Maintaining W+xN numbers reduces processing otherwise required, to start from scratch.