5006 results about "Fast Fourier transform" patented technology

Techniques are disclosed for converting data into a format tailored for efficient multidimensional fast Fourier transforms (FFTS) on single instruction, multiple data (SIMD) multi-core processor architectures. The technique includes converting data from a multidimensional array stored in a conventional row-major order into SIMD format. Converted data in SIMD format consists of a sequence of blocks, where each block interleaves s rows such that SIMD vector processors may operate on s rows simultaneously. As a result, the converted data in SIMD format enables smaller-sized 1D FFTs to be optimized in SIMD multi-core processor architectures.

A method for authenticating an individual by use of fingerprint data that involves two different broad steps. The first step is to obtain a biometrics fingerprint signature template (“BFST”) for an individual in an enrollment process by selecting a plurality of bands for the BFST and obtaining a plurality of tracks corresponding to each of the plurality of bands by use of an enrollment frame of a selected finger of the individual, wherein the plurality of bands are spatially referenced to the enrollment frame and can be spatially referenced to a reference barrier. The second step is to authenticate (or not) a candidate finger against one or more BFST in an authentication process in which a swipe direction and an access code for the individual are selected, a plurality of candidate tracks are obtained from the candidate finger through use of the reference barrier in an authentication unit so that each of the plurality of candidate tracks is spatially referenced so as to be within a corresponding one of the plurality of bands, calculating a similarity index for each of the plurality of candidate tracks and each of the plurality of tracks for the band to which the candidate track corresponds by use of a Fast Fourier-transform fingerprint algorithm, and multiplying each maximum similarity index obtained for each of the plurality of candidate tracks to obtain a match index which indicates a match if it exceeds a preselected threshold.

An OFDM (Orthogonal Frequency Division Multiplexing) communication system that multiplexes data with a plurality of orthogonal sub-carrier frequencies, which includes a transmitter for converting a serial data stream into parallel data, and segmenting the parallel data into a plurality of blocks having a plurality of data blocks; inserting reference data having information representing a phase value and a position into which the reference symbol is inserted, into each of the segmented blocks; IFFT (Inverse Fast Fourier Transform)-transforming the respective blocks into time-based signals where sub-carrier frequencies are separately assigned to the data blocks; and determining phase factors of the IFFT-transformed time-based signals to reduce a peak-to-average power ratio (PAPR) where non-linear distortion occurs due to coincidence of phases of the data blocks IFFT-transformed with the sub-carrier frequencies, and phase-rotating the IFFT-transformed signals according to the determined phase factors before transmission.

The present invention is directed toward a pulse oximetry system for the determination of a physiological parameter capable of removing motion artifacts from physiological signals comprises a hardware subsystem and a software subsystem. The software subsystem is used in conjunction with the hardware subsystem to perform a method for removing a plurality of motion artifacts from the photo-plethysmographic data and for obtaining a measure of at least one physiological parameter from the data. The method comprises acquiring the raw photo-plethysmographic data, transforming the data into the frequency domain, analyzing the transformed data to locate a series of candidate cardiac spectral peaks (primary plus harmonics), reconstructing a photo-plethysmographic signal in the time domain with only the candidate cardiac spectral peaks (primary plus harmonics), computing the second order derivative of the reconstructed photo-plethysmographic signal, analyzing the candidate second order derivative photo-plethysmographic signal to determine the absence or presence of cardiac physiologic signal characteristics, and finally selecting the best physiologic candidate from the series of potential cardiac spectral peaks (primary plus harmonics) based upon a second derivative scoring system. This scoring system is preferentially based upon second derivative processing analysis, but can be equally applied using the first, third, fourth or other similar derivative processing analysis.

A discrete multitone stacked-carrier spread spectrum communication method is based on frequency domain spreading including multiplication of a baseband signal by a set of superimposed, or stacked, complex sinusoid carrier waves. In a preferred embodiment, the spreading involves energizing the bins of a large Fast Fourier transform (FFT). This provides a considerable savings in computational complexity for moderate output FFT sizes. Point-to-multipoint and multipoint-to-multipoint (nodeless) network topologies are possible. A code-nulling method is included for interference cancellation and enhanced signal separation by exploiting the spectral diversity of the various sources. The basic method may be extended to include multielement antenna array nulling methods for interference cancellation and enhanced signal separation using spatial separation. Such methods permit directive and retrodirective transmission systems that adapt or can be adapted to the radio environment. Such systems are compatible with bandwidth-on-demand and higher-order modulation formats and use advanced adaptation algorithms. In a specific embodiment the spectral and spatial components of the adaptive weights are calculated in a unified operation based on the mathematical analogy between the spectral and spatial descriptions of the airlink.

For an information terminal to be operated by users for collecting predetermined pieces of information from remote information devices by free-space optical communication, the present invention provides a technique for suppressing the power consumption of the information terminal by minimizing the amount of calculation performed to collect the aforementioned information. According to the present invention, each information device emits ID light on which a low-frequency pilot signal is superimposed. The information terminal captures a series of frames of images including the ID light and locates the ID light within the images by the following steps: (1) creating multiple levels of binned images having different resolutions for each frame of the image; (2) calculating an evaluation index for each pixel within a target range of the binned images at each level, from the lowest to the highest resolution, where the target range is narrowed every time the process switches over to a lower level. In (2), the evaluation index is calculated by an evaluation function including fast Fourier transformation performed throughout the series of frames of images. The evaluation index thus calculated is compared with a threshold to determine whether the pixel concerned is receiving ID light. The present technique significantly reduces the number of pixel to be analyzed and evaluated, thereby decreasing the total number of arithmetic operations to be performed using the evaluation function. Thus, the power consumption is suppressed.