69 results about "Computational complexity theory" patented technology

The invention provides a visual ranging-based simultaneous localization and map construction method. The method includes the following steps that: a binocular image is acquired and corrected, so that a distortion-free binocular image can be obtained; feature extraction is performed on the distortion-free binocular image, so that feature point descriptors can be generated; feature point matching relations of the binocular image are established; the horizontal parallax of matching feature points is obtained according to the matching relations, and based on the parameters of a binocular image capture system, real space depth is calculated; the matching results of the feature points of a current frame and feature points in a world map are calculated; feature points which are wrongly matched with each other are removed, so that feature points which are successfully matched with each other can be obtained; a transform matrix of the coordinates of the feature points which are successfully matched with each other under a world coordinate system and the three-dimension coordinates of the feature points which are successfully matched with each other under a current reference coordinate system is calculated, and a pose change estimated value of the binocular image capture system relative to an initial position is obtained according to the transform matrix; and the world map is established and updated. The visual ranging-based simultaneous localization and map construction method of the invention has low computational complexity, centimeter-level positioning accuracy and unbiased characteristics of position estimation.

Methods and apparatus are provided for the creation and utilization of unique compressed data stream compositions, structures and formats which allow for the alteration of the data stream's data rate without first decoding the data stream back to its uncompressed form and then re-encoding the resulting uncompressed data at a different data rate. Such methods and apparatus perform this data rate alteration, known as scaling, such that optimal quality is maintained at each scaled data rate, while performing said scaling with low computational complexity. In addition, the present invention provides for data rate alteration in small increments. A unique application for the disclosed bit rate scaling method and apparatus is also described.

An error correction decoding (ECC) processing scheme is disclosed that reduces computational complexity normally associated with multiuser detection (e.g., TurboMUD) solutions, without causing degradation in quality of service or decreasing the total throughput. Error correction decoding algorithms are applied only to portions of the estimates that were affected by the immediately previous MUD update process. Even though the MUD and/or ECC updating is targeted so as to reduce complexity of each iteration, all of the estimates are maintained and remain candidates for future updates. As such, there is no negative impact real-time or future performance. This targeting approach can be used in conjunction with many variations of MUD, including full-complexity or reduced complexity, and may include MUD with confidence ordering or voting, and other techniques for facilitating efficient and effective MUD processing.

Bandwidth expansion for audio signals by frequency band translations plus adaptive gains to create higher frequencies; use of a common channel for both stereo channels limits computational complexity. Adaptive cut-off frequency determination by power spectrum curve analysis, and bass expansion by both fundamental frequency illusion and equalization.

A method of image processing is provided which includes non-recursive hysteresis thresholding in Canny edge detection. The non-recursive hysteresis thresholding reduces computational complexity and eliminates the potential for call stack overflow. More specifically, hysteresis thresholding is performed in a raster-scan order pass over the image data to connect edge segments to form continuous edges.

Several techniques aimed at reducing computational complexity when encoding uses bi-predictively encoded frames (B-frames) are implemented in a video encoder. In an embodiment, B-frames are not used as reference frames for encoding P-frames and other B-frames. Non-use of B-frames allows a de-blocking filter used in the video encoder to be switched off when reconstructing encoded B-frames, and use of a lower complexity filter for fractional-resolution motion search for B-frames. In another embodiment, cost functions used in motion estimation for B-frames are simplified to reduce computational complexity. In one more embodiment, fractional pixel refinement in motion search for B-frames is simplified. In yet another embodiment, predictors used in motion estimation for a macro-block in a P-frame are selected from a B-frame that uses a same reference frame as the P-frame.

A method for reducing computational complexity of video compression standard is provided, and it includes an intra 4×4 macroblock (I4MB) search algorithm, an intra 16×16 macroblock (I16MB) search algorithm and a chroma search algorithm. The I4MB search algorithm and I16MB search algorithm accelerate the prediction process of the luma macroblock, and the chroma search algorithm accelerates the prediction process of chroma macroblock. The above algorithms can greatly reduce the computation of prediction mode of video compression standard.

A decision tree for classifying computer files is constructed. Computational complexities of a set of candidate attributes are determined. A set of attribute vectors are created for a set of training files with known classification. A node is created to represent the set. A weighted impurity reduction score is calculated for each candidate attribute based on the computational complexity of the attribute. If a stopping criterion is satisfied then the node is set as a leaf node. Otherwise the node is set as a branch node and the attribute with the highest weighted impurity reduction score is selected as the splitting attribute for the branch node. The set of attribute vectors are split into subsets based on their attribute values of the splitting attribute. The above process is repeated for each subset. The tree is then pruned based on the computational complexities of the splitting attributes.

A method for encoding video data includes the steps of providing video data having a plurality of frames each of which has a plurality of blocks each of which has a predetermined number of pixels, providing a codebook having indices each representing a different pattern, performing an intra-coding process with respect to a first set of frames of the plurality of frames to select from the codebook best match indices for respective blocks of the first set of frames, performing a predictive coding process with respect to a second set of frames of the plurality of frames to obtain codes for respective blocks of the second set of frames, wherein each of the codes has an index-body determined using the best match indices for the blocks of the first set of frames and best match indices selected from the codebook for the blocks of the second set of frames, and performing a bi-directional predictive coding process with respect to a third set of frames of the plurality of frames to obtain codes for respective blocks of the third set of frames, wherein each of the codes has an index-body determined using the best match indices for the blocks of the first and second sets of the frames and best match indices selected from the codebook for the blocks of the third set of frames.

The reuse partitioning problem for a cellular orthogonal frequency division multiple access (OFDMA) system with dynamic subcarrier allocation is considered. One objective is to allocate the network resources in an efficient way in order to maximize the system's total throughput under individual user's quality-of-service (QoS) constraint. A suboptimal two-step approach is used where the radio network controller (RNC) solves the network planning problem and each base station (BS) solves the cell throughput maximization problem. Compared with the optimal resource allocation scheme, the approach described herein has much lower computational complexity in the RNC. Moreover, the communication overhead between each BS and the RNC is reduced substantially which renders our approach more practical for delay sensitive applications. Throughput increase is demonstrated

In an embodiment, computational complexity of estimating the actual illuminant of a scene is reduced by examining only a subset of the pixel values generated for a received image frame. In another embodiment, number of rotations of color values is minimized by selecting an area which contains the color cue values of a color in an original/unrotated coordinate space and has boundaries which parallel the axis of the original coordinate space, and rotating a color value only if the color value is within the selected area. In another embodiment, such an area is used in conjunction with a histogram-based approach to determine the actual illuminant.

The invention discloses a system evaluation and detection method by a Bayesian model. The method includes: step A, establishing a logic relationship and an event relationship between a software system and a database therein after variable and relationship conversion; step B, establishing a fault tree model for a logic model according to the step A; step C, establishing a Bayesian network based on the fault tree model; step D, conducting system evaluation and detection based on the Bayesian network. The system evaluation and detection method by the Bayesian model has the advantages of low computational complexity, low computational difficulty, simplicity and practicality when used for system evaluation and detection by the Bayesian model.

The invention provides a modulation format recognition method, which adopts high-order cumulant of signals in a Stokes space and clustering center points clustered based on a DENCLUE algorithm as characteristic parameters for recognizing modulation format signals; a simple decision tree classifier is adopted; the method has low computational complexity and is insensitive to optical fiber channel damage such as polarization rotation, carrier frequency deviation, carrier phase noise and the like; recognition with relatively high accuracy can be realized under the condition of low signal-to-noiseratio; the modulation format recognition method is high in fusion degree with an existing commercial optical fiber communication system and is easy to upgrade from an existing system.

A modified orthogonal frequency-division multiplexing (OFDM) communication system based on virtual decomposition of the channel is proposed. The system is fully compatible with standard OFDM transmitters and maintains several blocks of standard OFDM receivers. The proposed approach achieves also incoherent reception of multicarrier signals even with a simple autocovariance DPSK detector. This novel system substantially surpasses the performance of current approaches while requiring low computational complexity. Two preferred embodiments are described; one with coherent reception using pilot signals, and the second with incoherent receiver of differentially encoded signals.

The present invention is a method to accelerate the frame/field decision by estimating more suitable structure using SAD (sum of absolute difference) between picture samples and their mean. Next the uses the correlation observed between the optimal macroblock prediction modes found with the inferred structure and the probability of the non-inferred structure being better than the inferred one. The invention can lead to the significant reduction of the computational complexity at the cost of slight degradation of coding efficiency.

The invention provides a binary classification method based on seepage analysis, which comprises the following steps: 1, constructing an index network based on a data vector; 2, seepage analysis of index network; 3, constructing a likelihood function and determining a key threshold; 4. evaluation and validation of the model. Through the above steps, the invention further provides technical supportand theoretical support for large-scale, high-dimensional and high-complexity system group classification and evaluation classification effect based on seepage analysis; in addition, the background knowledge is expressed by graph model and the network analysis is carried out by using the seepage theory based on phase change, which reduces the computational complexity, converges quickly and is suitable for large-scale computation and reduces the computational cost.

A multiuser detector that detects and decodes synchronous or asynchronous CDMA subchannels having different spreading factors with reduced computational complexity. The multiuser detector is compatible with ZF-BLE, MMSE, decorrelating detectors and the like using Cholesky decomposition to minimize numeric operations. The system and method arranges the columns of system transmission response matrices representing the response characteristics of individual users into a total system transmission response matrix which represents a plurality of matched-filter responses for a given block of received data. The invention in conjunction with Cholesky decomposition reduces the number of required mathematic operations prior to parallel matched filtering.

The invention relates to the interpolation point computing technology of a numerical control system, in particular to a computational complexity self-adaptation NURBS splined interpolation method. By analyzing the computing structure generated when an interpolation point is computed with a de Boor-Cox method, a computational complexity formula for solving the interpolation point is built; the computing structure generated when the interpolation point is computed with a basis function method is simplified, the computational complexity is reduced by sharing an intermediate result, and a computational complexity formula used in the solving process of the basis function method is built; the performance judgment formulas generated when the interpolation point is computed with the de Boor-Cox method and the basis function method are built, and in the splined interpolation process, the method low in computational complexity is dynamically selected through the performance judgment formulas for interpolation. By the application of the method, the intermediate result in the computing process of a basis function algorithm can be effectively shared, the computational complexity of the algorithm is reduced, an efficient interpolation algorithm can be dynamically selected in a self-adaptation mode, and the NURBS splined interpolation efficiency is improved.