Abstract: In various implementations a method includes obtaining a plurality of source images, stabilizing the plurality of source images to generate a plurality of stabilized images, and averaging the plurality of stabilized image to generate a synthetic long exposure image. In various implementations, stabilizing the plurality of source images includes: selecting one of the plurality of source images to serve as a reference frame; and registering others of the plurality of source images to the reference frame by applying a perspective transformation to others of the plurality of the source images.

Abstract: Techniques and devices for creating a Forward-Reverse Loop output video and other output video variations. A pipeline may include obtaining input video and determining a start frame within the input video and a frame length parameter based on a temporal discontinuity minimization. The selected start frame and the frame length parameter may provide a reversal point within the Forward-Reverse Loop output video. The Forward-Reverse Loop output video may include a forward segment that begins at the start frame and ends at the reversal point and a reverse segment that starts after the reversal point and plays back one or more frames in the forward segment in a reverse order. The pipeline for the generating Forward-Reverse Loop output video may be part of a shared resource architecture that generates other types of output video variations, such as AutoLoop output videos and Long Exposure output videos.

Abstract: In various implementations a method includes obtaining a plurality of source images, stabilizing the plurality of source images to generate a plurality of stabilized images, and averaging the plurality of stabilized image to generate a synthetic long exposure image. In various implementations, stabilizing the plurality of source images includes: selecting one of the plurality of source images to serve as a reference frame; and registering others of the plurality of source images to the reference frame by applying a perspective transformation to others of the plurality of the source images.

Abstract: Techniques and devices for creating an AutoLoop output video include performing postgate operations. The AutoLoop output video is created from a set of frames. After generating the AutoLoop output video based on a plurality of loop parameters and at least a portion of the frames, postgate operations determine one or more dynamism metrics based on a variability metric and a dynamic range metric for a plurality of pixels within the video loop. Postgate operations compare the dynamism metrics to one or more postgate threshold values and reject the video loop based on the comparison of the dynamism metrics to the postgate threshold values.

Abstract: Techniques and devices for creating an AutoLoop output video include performing pregate operations. The AutoLoop output video is created from a set of frames. Prior to creating the AutoLoop output video, the set of frames are automatically analyzed to identify one or more image features that are indicative of whether the image content in the set of frames is compatible with creating a video loop. Pregate operations assign one or more pregate scores for the set of frames based on the one or more identified image features, where the pregate scores indicate a compatibility to create the video loop based on the identified image features. Pregate operations automatically determine to create the video loop based on the pregate scores and generate an output video loop based on the loop parameters and at least a portion of the set of frames.

Abstract: Techniques and devices for creating an AutoLoop output video include identifying optimal loops within short videos or within a series of image. The AutoLoop output video may be automatically created using casually shot, handheld videos, and may include an AutoLoop pipeline that may comprise obtaining an input video, stabilizing the input video, detecting optimal loop parameters and baking out the AutoLoop output video with crossfade and playing back the AutoLoop output video. Video stabilization can include a cascade of video stabilization algorithms including a tripod-direct mode and a tripod-sequential mode. After stabilization, an AutoLoop operation may determine optimal loop parameters. Once optimal loop parameters are determined, a crossfade may be added to smooth out any temporal and spatial discontinuities in the AutoLoop output video.

Abstract: Techniques and devices for creating an AutoLoop output video by adding synthetic camera motion to the AutoLoop output video. The AutoLoop output video is created from a set of frames. After generating the AutoLoop output video based on a plurality of loop parameters and at least a portion of the frames, synthetic camera motion is combined with the AutoLoop output video. The synthetic camera loop is based on the subset of the input frames and exhibits some amount of camera motion for the subset of the input frames. Once the synthetic camera loop is generated, the synthetic camera loop and the video loop is combined to enhance the AutoLoop output video.

Abstract: Techniques and devices for creating an AutoLoop output video include identifying optimal loops within short videos or within a series of image. The AutoLoop output video may be automatically created using casually shot, handheld videos, and may include an AutoLoop pipeline that may comprise obtaining an input video, stabilizing the input video, detecting optimal loop parameters and baking out the AutoLoop output video with crossfade and playing back the AutoLoop output video. Video stabilization can include a cascade of video stabilization algorithms including a tripod-direct mode and a tripod-sequential mode. After stabilization, an AutoLoop operation may determine optimal loop parameters. Once optimal loop parameters are determined, a crossfade may be added to smooth out any temporal and spatial discontinuities in the AutoLoop output video.

Abstract: Techniques and devices for creating an AutoLoop output video include performing postgate operations. The AutoLoop output video is created from a set of frames. After generating the AutoLoop output video based on a plurality of loop parameters and at least a portion of the frames, postgate operations determine one or more dynamism metrics based on a variability metric and a dynamic range metric for a plurality of pixels within the video loop. Postgate operations compare the dynamism metrics to one or more postgate threshold values and reject the video loop based on the comparison of the dynamism metrics to the postgate threshold values.

Abstract: Techniques and devices for creating an AutoLoop output video by adding synthetic camera motion to the AutoLoop output video. The AutoLoop output video is created from a set of frames. After generating the AutoLoop output video based on a plurality of loop parameters and at least a portion of the frames, synthetic camera motion is combined with the AutoLoop output video. The synthetic camera loop is based on the subset of the input frames and exhibits some amount of camera motion for the subset of the input frames. Once the synthetic camera loop is generated, the synthetic camera loop and the video loop is combined to enhance the AutoLoop output video.

Abstract: Techniques and devices for creating an AutoLoop output video include performing pregate operations. The AutoLoop output video is created from a set of frames. Prior to creating the AutoLoop output video, the set of frames are automatically analyzed to identify one or more image features that are indicative of whether the image content in the set of frames is compatible with creating a video loop. Pregate operations assign one or more pregate scores for the set of frames based on the one or more identified image features, where the pregate scores indicate a compatibility to create the video loop based on the identified image features. Pregate operations automatically determine to create the video loop based on the pregate scores and generate an output video loop based on the loop parameters and at least a portion of the set of frames.

Abstract: Techniques and devices for creating a Forward-Reverse Loop output video and other output video variations. A pipeline may include obtaining input video and determining a start frame within the input video and a frame length parameter based on a temporal discontinuity minimization. The selected start frame and the frame length parameter may provide a reversal point within the Forward-Reverse Loop output video. The Forward-Reverse Loop output video may include a forward segment that begins at the start frame and ends at the reversal point and a reverse segment that starts after the reversal point and plays back one or more frames in the forward segment in a reverse order. The pipeline for the generating Forward-Reverse Loop output video may be part of a shared resource architecture that generates other types of output video variations, such as AutoLoop output videos and Long Exposure output videos.

Abstract: Psychovisual image compression techniques are disclosed that compress pixel data by a fixed compression ratio with little or no perceptual loss of detail. In some implementations, a psychovisual compression process is selected among several psychovisual compression processes based on characteristics of the pixel data. Compression is achieved during encoding by discarding psychovisually unnecessary bits from the pixel data. The psychovisual compression processes can be implemented in hardware and operate on scan lines of pixels captured by the image sensor. The psychovisual compression techniques can be used with image compression techniques to compress further the pixel data.

Abstract: Psychovisual image compression techniques are disclosed that compress pixel data by a fixed compression ratio with little or no perceptual loss of detail. In some implementations, a psychovisual compression process is selected among several psychovisual compression processes based on characteristics of the pixel data. Compression is achieved during encoding by discarding psychovisually unnecessary bits from the pixel data. The psychovisual compression processes can be implemented in hardware and operate on scan lines of pixels captured by the image sensor. The psychovisual compression techniques can be used with image compression techniques to compress further the pixel data.

Abstract: One embodiment of the present invention provides a system that establishes a secure connection with a peer. During operation, the system obtains an identity for the peer. Next, the system looks up the identity for the peer in a local store, which contains identities for trusted peers. If this lookup fails, the system asks a user if the peer can be trusted. If the user indicates that the peer can be trusted, the system establishes a secure connection with the peer.

Abstract: A method of generating a digital signature includes generating a first random number from a finite field of numbers, and generating field elements defining a first point on an elliptic curve defined over the finite field of numbers by performing elliptic curve arithmetic on the first random number and an initial public point on the elliptic curve. The method continues by generating a product from a field element, a private key, and a second random number received from a challenger seeking verification of a digital signature, and generating a signature component by summing the product and the first random number. The signature component is reduced using one or more modular reduction operations, using a modulus equal to an order of the elliptic curve, and then the reduced signature component and the field elements are sent to the challenger as a digital signature for verification by the challenger.

Abstract: A method of generating a digital signature includes generating a first random number from a finite field of numbers, and generating field elements defining a first point on an elliptic curve defined over the finite field of numbers by performing elliptic curve arithmetic on the first random number and an initial public point on the elliptic curve. The method continues by generating a product from a field element, a private key, and a second random number received from a challenger seeking verification of a digital signature, and generating a signature component by summing the product and the first random number. The signature component is reduced using one or more modular reduction operations, using a modulus equal to an order of the elliptic curve, and then the reduced signature component and the field elements are sent to the challenger as a digital signature for verification by the challenger.

Abstract: A chaos generator for accumulating stream entropy is disclosed. The chaos generator includes a random source coupled to an entropy accumulator that is configurable for generating a binary random input sequence. The entropy accumulator is configurable for accumulating entropy of the input sequence and providing a binary random output sequence based on the accumulated entropy. The binary random output sequence is reduced by a modular reduction operation having a modulus that is set equal to a cryptographic prime (e.g., the order of an elliptic curve). The number of iterations performed by the entropy accumulator on the binary random input sequence is selected to provide a binary random output sequence having a desired cryptographic strength. The chaos generator can be part of a signing and verification system that uses fast elliptic encryption for small devices.

Abstract: A method of generating a digital signature includes generating a first random number from a finite field of numbers, and generating field elements defining a first point on an elliptic curve defined over the finite field of numbers by performing elliptic curve arithmetic on the first random number and an initial public point on the elliptic curve. The method continues by generating a product from a field element, a private key, and a second random number received from a challenger seeking verification of a digital signature, and generating a signature component by summing the product and the first random number. The signature component is reduced using one or more modular reduction operations, using a modulus equal to an order of the elliptic curve, and then the reduced signature component and the field elements are sent to the challenger as a digital signature for verification by the challenger.