Abstract: A system and method implementing a hierarchical approach to RTM (Reverse Time Migration) seismic imaging at different granularity in space and time. An RTM seismic imaging algorithm utilizes RTM technique to convert a parallel problem into one solved using massive domain partitioning. In the method, a coarse-grain grid for the 3D volume of the geological subsurface structure under investigation is initially processed, permitting the RTM imaging process to be performed faster and produces lower level seismic image for inspection. Criteria are then applied to the first level of seismic image to determine whether to reject the image or whether a finer resolution seismic imaging is needed. In the case of finer resolution is needed, RTM resolution for the target volume is adjusted accordingly and RTM imaging process is applied with the new resolution. The process is repeated until either the image is accepted or rejected.

Abstract: A system, method and computer program product for seismic imaging implements a seismic modeling algorithm utilizing Forward Wave Inversion technique for revising Reverse Time Migration models used for sub-surface modeling. The technique requires large communication bandwidth and low latency to convert a parallel problem into one solved using massive domain partitioning. The partitioning of a velocity model into processing blocks allows each sub-problem to fit in a local cache, increasing locality and bandwidth and reducing latency. The RTM seismic data processing utilizes data that includes combined shot data, i.e., shot data selected from amongst a plurality of shots that are combined at like spatial points of the volume. An iterative approach is applied such that the correction term RTM generates at each iteration in the iterative approach is used for refining the model, and the updated model is used for generating a further refined RTM model.

Abstract: A method and system are disclosed for selecting a mode to encode video data. The method comprises the steps of (a) transforming a source video frame into a set of coefficients, (b) partitioning said set of coefficients into a plurality of subsets of the coefficients on the basis of probability statistics corresponding to a plurality of encoding modes, wherein each of said subsets is identified for encoding by one of the plurality of encoding modes. The method comprises the further steps of (c) for each of the plurality of subsets of coefficients, computing defined parameters of an associated probability distribution for said subset, and (d) repeating steps (b) and (c) until a predetermined termination condition is satisfied. When this predetermined termination condition is satisfied, the subsets of coefficients, as they exist at that time, are output to a video encoder, which preferably is a Wyner-Ziv encoder.

Abstract: A video transcoding method is provided for transcoding a first signal stream compressed by a first coding scheme to a second signal stream compressed by a second coding scheme. The method employs an adaptive frame rate and a joint temporal-spatial rate control technique, such that the overall quality of compressed MPEG video can be significantly enhanced when the transcoding is controlled in the joint temporal (picture or frame rate) and spatial (quantization) domains. One embodiment considers transcoding from high bit rate video with larger image size (e.g. 4CIF/4SIF, CIF) coded by one coding technique, e.g., MPEG-2 to a lower bit rate video with smaller image size (e.g. CIF, QCIF) coded by the same or another coding technique, e.g., MPEG-4.

Abstract: A method and system are disclosed for selecting a mode to encode video data. The method comprises the steps of (a) transforming a source video frame into a set of coefficients, (b) partitioning said set of coefficients into a plurality of subsets of the coefficients on the basis of probability statistics corresponding to a plurality of encoding modes, wherein each of said subsets is identified for encoding by one of the plurality of encoding modes. The method comprises the further steps of (c) for each of the plurality of subsets of coefficients, computing defined parameters of an associated probability distribution for said subset, and (d) repeating steps (b) and (c) until a predetermined termination condition is satisfied. When this predetermined termination condition is satisfied, the subsets of coefficients, as they exist at that time, are output to a video encoder, which preferably is a Wyner-Ziv encoder.

Abstract: Disclosed are a method and system for video compression, wherein the video encoder has low computational complexity and high compression efficiency. The disclosed system comprises a video encoder and a video decoder, wherein the method for encoding includes the steps of converting a source frame into a space-frequency representation; estimating conditional statistics of at least one vector of space-frequency coefficients; estimating encoding rates based on the said conditional statistics; and applying Slepian-Wolf codes with the said computed encoding rates. The preferred method for decoding includes the steps of; generating a side-information vector of frequency coefficients based on previously decoded source data, encoder statistics, and previous reconstructions of the source frequency vector; and performing Slepian-Wolf decoding of at least one source frequency vector based on the generated side-information, the Slepian-Wolf code bits and the encoder statistics.

Abstract: A method (and system) for coding a signal includes comparing a first prediction which is based upon a previously reconstructed signal to an actual signal to determine a first prediction error, comparing a second prediction which is based upon temporal filtering to the actual signal to determine a second prediction error, and selecting one of the first prediction error and the second prediction error.

Abstract: A method and system provide for secure sharing of arbitrary data between users with limited mutual trust. A user can encode its information by using a Slepian-Wolf code at a rate which enables a second user to correctly decode only if the side-information it has satisfies a conditional entropy constraint. The key advantages are as follows. Firstly, it is very flexible, in that it enables secure sharing for general data including multimedia data. Secondly, by appropriate Slepian-Wolf code selection, it enables compression in conjunction with security. Thirdly, it can be used for the case where the data model is imperfectly known and trust is to be built up incrementally.

Abstract: A method for wireless video streaming includes determining a backhaul bandwidth of a base station and ongoing traffic between a plurality of wireless clients and the base station, determining a video transcoding policy for each of the wireless clients based on a service agreement of each wireless client, decoding network signaling information, extracting a plurality of video streams based on the decoded network signaling information, and transcoding the plurality of video streams simultaneously upon determining that the ongoing traffic exceeds the backhaul bandwidth. Transcoding is based on a video transcoding policy of a receiving wireless client, video properties of a video stream being transcoded, and the decoded network signaling information.

Abstract: Techniques are disclosed for parallel computing of a line of sight (LoS) map (e.g., view-shed) in a parallel computing system. For example, a method for computing an LoS map comprises the following steps. Data representing at least one image is obtained. An observation point in the at least one image is identified. A portion of the data that is associated with a given area in the image is partitioned into a plurality of sub-areas. The plurality of sub-areas are assigned to a plurality of processor elements of a parallel computing system, respectively, such that the data associated with each one of the plurality of sub-areas is processed independent from the data associated with each other of the plurality of sub-areas, wherein results of the processing by the processor elements represents the LoS map. The parallel computing system may be a multicore processor.

Abstract: Methods and apparatus are provided for encoding video, such as surveillance video. A video frame is encoded by evaluating a level of activity in video frame relative to one or more neighboring frames; encoding the video frame using an inter-coding technique if the evaluation satisfies one or more predefined inter-coding criteria, wherein said inter-coding technique is applied to said video frame without a Group of Picture structure having a maximum number of consecutive inter-coded frames; and encoding the video frame using an intra-coding technique if the evaluation satisfies one or more predefined intra-coding criteria. The evaluating step may comprise, for example, determining whether differences between the video frame and the one or more neighboring frames exceed a predefined threshold.

Abstract: Methods and apparatus are provided for secure distribution and storage of data using N channels. An input data sequence, X, is distributed using a plurality, N, of channels. In one embodiment, the input data sequence, X, is split into N subsequences; and the N subsequences are encoded into N bit streams using a set of Slepian-Wolf codes with N separate encoders and a joint decoder. The Slepian-Wolf codes can be selected to ensure a computational complexity to obtain a portion of the input data sequence grows exponentially with respect to a length of the input data sequence unless all of the N bit streams are compromised. In another embodiment, the input data sequence, X, is compressed using a lossless data compressing techniques; and the compressed input data sequence is split into N subsequences that are distributed.

Abstract: The present invention relates to computer-based systems and methods for visual signal extrapolation or interpolation based on statistic similarity estimation. Specifically, a first and a second reference pictures are provided, and motion estimation is conducted on the first and second reference pictures to generate motion vectors indicative of movement of at least one of the first and second reference pictures in relation to the other. Subsequently, an estimate picture is generated by extrapolation or interpolation from the first and/or the second reference picture using the motion vectors, followed by optional refinement of the estimate picture. Statistic similarity estimation is used either in motion estimation or in refining the estimate picture, or a combination of both, so as to provide improved visual signals.

Abstract: The present invention relates to computer-based systems and methods for visual signal extrapolation or interpolation based on statistic similarity estimation. Specifically, a first and a second reference pictures are provided, and motion estimation is conducted on the first and second reference pictures to generate motion vectors indicative of movement of at least one of the first and second reference pictures in relation to the other. Subsequently, an estimate picture is generated by extrapolation or interpolation from the first and/or the second reference picture using the motion vectors, followed by optional refinement of the estimate picture. Statistic similarity estimation is used either in motion estimation or in refining the estimate picture, or a combination of both, so as to provide improved visual signals.

Abstract: A method and system for extrapolating and interpolating a visual signal including determining a first motion vector between a first pixel position in a first image to a second pixel position in a second image, determining a second motion vector between the second pixel position in the second image and a third pixel position in a third image, determining a third motion vector between one of the first pixel position in the first image and the second pixel position in the second image, and the second pixel position in the second image and the third pixel position in the third image using a non-linear model, determining a position of the fourth pixel in a fourth image based upon the third motion vector.

Abstract: A plurality of data streams are obtained; they may be compressed, uncompressed, or a mixture of compressed and uncompressed. Statistical parameters associated with each of the data streams are determined. A plurality of storage constraints are obtained. A plurality of output bit rates are determined for encoding or transcoding, as the case may be, each of the data streams, based on the statistical parameters and the storage constraints. The output bit rates are determined to jointly reduce (and preferably minimize) an overall cost. The overall cost includes the cost associated with storing compressed versions of the data streams. For each of the data streams, the encoding or transcoding into the compressed versions, is carried out in accordance with the output bit rates.

Abstract: A method and apparatus for decompressing data in a data-compression system with decoder-only side information is provided. In one aspect, the method comprises generating side information using a source reconstruction and decoding using the generated side information to generate a new source reconstruction. The method further includes iterating the steps of generating and decoding, the generating step using at least the new source reconstruction output by the previous decoding step, and the decoding step using the side information output by the previous generating step. The method may stop the iteration when one or more predetermined criteria are met.

Abstract: A plurality of input data streams, from a plurality of data sources, are identified. The input data streams are in a plurality of different formats. For each of the input data streams, one of a plurality of transcoders is selected, to obtain a transcoding plan. Each of the plurality of transcoders has an associated transcoding cost. A potential output for each of the plurality of transcoders has an associated storage cost, and the selecting step includes jointly reducing the overall cost, subject to appropriate constraints. The method can be employed, for example, for designing a new system or efficiently utilizing an existing system. The plurality of streams can be transcoded in accordance with the plan.

Abstract: A real-time MPEG video coding system with information look-ahead for constant bit rate (CBR) applications, such as, for example, Video-on-Demand (VoD) over ADSL. This scheme employs two MPEG encoders. The second encoder has a buffer to delay the input by an amount of time relative to the first encoder to create a look-ahead window. In encoding, the first encoder collects the information of statistics and rate-quality characteristics. An on-line information processor then uses the collected information to derive the best coding strategy for the second encoder to encode the incoming frames in the look-ahead window. The second encoder uses the encoding parameters from the processor as the coding guide to execute the coding strategy and generate the final bitstream.

Abstract: A decoding power aware encoding method for generating a predictively encoded data stream, in which predictions, that result in a reduction in the amount of data transferred from the secondary memory to primary memory during the decoding process, are favored, said method for favoring certain predictions comprising: a model for transfer of data from secondary memory to primary memory in the decoding process; a scheme for weighting the relative merits of favoring a certain prediction and the associated loss in compression gain; and based on said weighting scheme, choosing a particular prediction from the candidates allowed by the compression scheme.