摘要:
A duty cycle scheme for wireless communication employs three or more duty cycle levels. In some aspects, a wireless device may continually scan for signals in an active state associated with a first duty cycle, periodically scan for signals during a periodic state associated with a second duty cycle, and periodically scan for signals during a standby state associated with a third duty cycle. Here, the second duty cycle may be lower than the first duty cycle and the third duty cycle may be lower than the second duty cycle. In some aspects the timing of different states may be correlated. In some aspects each wireless device in a system may independently control its duty cycle states.
摘要:
Media access control is provided for an ultra-wide band medium. The media access control may employ a peer-to-peer network topology. The media access control may employ a reduced addressing scheme. Concurrent ultra-wide band channels may be established through the use of a pulse division multiple access channelization scheme. Multiple media access control states may be defined whereby each state may be associated with one or more of different channel parameter state information, different duty cycles, and different synchronization status.
摘要:
Apparatus and method for processing signals. A sigma-delta modulator is used. An adaptive dynamic range controller is configured to adaptively adjust the dynamic range of a signal output from the sigma-delta modulator.
摘要:
This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for accurately positioning a movable conductive layer of a reflective display element. In one aspect, an initial position of the movable conductive layer with respect to at least one or more fixed conductive layers is sensed. A charging voltage may be determined based at least in part on the initial position. The charging voltage may be applied to the movable conductive layer.
摘要:
Various arrangements for using a k-dimensional tree for a search are presented. A plurality of descriptors may be stored. Each of the plurality of descriptors stored is linked with a first number of stored dimensions. The search may be performed using the k-dimensional tree for one or more query descriptors that at least approximately match one or more of the plurality of descriptors linked with the first number of stored dimensions. The k-dimensional tree may be built using the plurality of descriptors wherein each of the plurality of descriptors is linked with a second number of dimensions when the k-dimensional tree is built. The second number of dimensions may be a greater number of dimensions than the first number of stored dimensions.
摘要:
A method for feature matching in image recognition is provided. First, image scaling may be based on a feature distribution across scale spaces for an image to estimate image size/resolution, where peak(s) in the keypoint distribution at different scales is used to track a dominant image scale and roughly track object sizes. Second, instead of using all detected features in an image for feature matching, keypoints may be pruned based on cluster density and/or the scale level in which the keypoints are detected. Keypoints falling within high-density clusters may be preferred over features falling within lower density clusters for purposes of feature matching. Third, inlier-to-outlier keypoint ratios are increased by spatially constraining keypoints into clusters in order to reduce or avoid geometric consistency checking for the image.
摘要:
A normalization process is implemented at a difference of scale space to completely or substantially reduce the effect that illumination changes has on feature/keypoint detection in an image. An image may be processed by progressively blurring the image using a smoothening function to generate a smoothened scale space for the image. A difference of scale space may be generated by taking the difference between two different smoothened versions of the image. A normalized difference of scale space image may be generated by dividing the difference of scale space image by a third smoothened version of the image, where the third smoothened version of the image that is as smooth or smoother than the smoothest of the two different smoothened versions of the image. The normalized difference of scale space image may then be used to detect one or more features/keypoints for the image.
摘要:
In some embodiments, first information indicative of an image of a scene is accessed. One or more reference features are detected, the reference features being associated with a reference object in the image. A transformation between an image space and a real-world space is determined based on the first information. Second information indicative of input from a user is accessed, the second information identifying an image-space distance in the image space corresponding to a real-world distance of interest in the real-world space. The real-world distance of interest is then estimated based on the second information and the determined transformation.
摘要:
In some embodiments, methods and systems are provided for assisting a user in determining a real-world distance. Hardware-based sensors (e.g., present in a mobile electronic device) may allow for a fast low-power determination of distances. In one embodiment, one or more telemetry-related sensors may be incorporated into a device. For example, data detected by a frequently-calibrated integrated accelerometer may be used to determine a tilt of the device. A device height may be estimated based on empirical data or based on a time difference between a signal (e.g., a sonar signal) emitted towards the ground and a corresponding detected signal. A triangulation technique may use the estimated tilt and height to estimate other real-world distances (e.g., from the device to an endpoint or between endpoints).
摘要:
Various arrangements for using a k-dimensional tree for a search are presented. A plurality of descriptors may be stored. Each of the plurality of descriptors stored is linked with a first number of stored dimensions. The search may be performed using the k-dimensional tree for one or more query descriptors that at least approximately match one or more of the plurality of descriptors linked with the first number of stored dimensions. The k-dimensional tree may be built using the plurality of descriptors wherein each of the plurality of descriptors is linked with a second number of dimensions when the k-dimensional tree is built. The second number of dimensions may be a greater number of dimensions than the first number of stored dimensions.