Recent Patents in Signal Processing (April 2015) – Wavelet analysis

For our April 2015 issue, we cover recent patents granted in the area of wavelet analysis. The section below covers patents granted recently for seismic data analysis, image stream compression, audio identification, continuous wavelet estimation, multidimensional data analysis, motion tracking, dispersion measurement, time domain network analysis, and video fingerprinting.

In patent no. 8,990,053 a wavelet estimation method is introduced, particularly advantageous for full wavefield inversion ("FWI") of seismic data, that makes use of both the primary and multiple reflections in the data. The inventive method uses an FWI algorithm to generate a subsurface model from primary reflections (101) in a shallow layer before first arrival of multiple reflections (101). The model is then used to simulate multiples (102). The wavelet is subsequently modified (104) such that the simulated multiples closely match the true recorded multiples (103). The simulated multiples may then be subtracted from the measured data (105) thereby creating a deeper top layer of data substantially free of multiples, and the method may then be repeated to extend the subsurface model to a greater depth (106).

In the embodiment no. 8,989,509, a compression unit is provided which may perform compression of a pixel stream. Similarly, a decompression unit may be provided which may decompress the compressed pixel stream. The compression and decompression units may include a streaming wavelet transform, which may perform the wavelet transform through a pipeline of wavelet operations. Each section of the pipeline may perform a pass of the wavelet transform on the pixel stream, and the section may provide input to another section of the pipeline that performs a next pass of the wavelet transform. The transform may thus be performed on the fly as the pixels are received.

This invention no. 8,981,971 is for a method for transforming a seismic trace into a compressed domain. The seismic source wavelet is transformed into a zero degree phase wavelet and a shifted 90 degree phase wavelet, and the two wavelets span a 2-dimensional sub-space. A dictionary is created by collecting the wavelets in the sub-space. In practice this dictionary is usually combined with conventional existing wavelet dictionaries. The seismic trace is projected onto the dictionary (sub-space alone or combined) to find the best matching projection, with a residual determined after each projection, wherein the sum of the residuals determines the fidelity of the data compression.

In patent no. 8,977,067 a method is described that includes producing an audio spectrogram from a target sample, generating a number of fingerprints based on the audio spectrogram, comparing the series of fingerprints to samples in a data repository using wavelet coefficients, and identifying the target sample based on the matches found in the data repository.

According to embodiments no. 8,954,127, techniques for estimating scalogram energy values in a wedge region of a scalogram are disclosed. A pulse oximetry system including a sensor or probe may be used to receive a photoplethysmograph (PPG) signal from a patient or subject. A scalogram, corresponding to the obtained PPG signal, may be determined. In an arrangement, energy values in the wedge region of the scalogram may be estimated by calculating a set of estimation locations in the wedge region and estimating scalogram energy values at each location. In an arrangement, scalogram energy values may be estimated based on an estimation scheme and by combining scalogram values in a vicinity region. In an arrangement, the vicinity region may include energy values in a resolved region of the scalogram and previously estimated energy values in the wedge region of the scalogram. In an arrangement, one or more signal parameters may be determined based on the resolved and estimated values of the scalogram.

The invention no. 8,885,974 concerns a method of converting raw multidimensional digital data corresponding to points making up a 2D or 3D image of unknown size and an associated system. The method comprises: the sizing a multidimensional window for traversing of said image, the said sizing depending on the size of a buffer; the traversing the said image comprising the movement of the said window in the image along the axes of the image; at each position of the said window in the image: the step of acquisition and loading, in the said buffer, of the data of the part of the image defined by the window; the conversion by calculation of the multidimensional wavelet transform of the said loaded part by means of at least one compact support filter for generating low- and high-frequency coefficients; the saving of the said coefficients generated. Application to wavelet transformation synchronously with the acquisition of medical or seismic images.

The invention no. 8,848,976 relates to a video tracker which allows automatic tracking of a selected area over video frames. Motion of the selected area is defined by a parametric motion model. In addition to simple displacement of the area it can also detect motions such as rotation, scaling and shear depending on the motion model. The invention realizes the tracking of the selected area by estimating the parameters of this motion model in the complex discrete wavelet domain. The invention can achieve the result in a non-iterative direct way. Estimation carried out in the complex discrete wavelet domain provides a robust tracking opportunity without being effected by noise and illumination changes in the video as opposed to the intensity-based methods. The invention can easily be adapted to many fields in addition to video tracking.

Patent no. 8,848,176 introduces a dispersion measurement apparatu, which includes: a pulse generator to output optical pulses including an optical pulse with a first wavelength and an optical pulse with a second wavelength to an optical transmission path, the second wavelength being different from the first wavelength; a reception pulse analyzer including an optical receiver that receives the optical pulses output by the pulse generator, and an analyzer that performs a wavelet transform on an electrical pulse output through the reception performed by the optical receiver; and a calculator to detect, based on a result of the wavelet transform, a time difference between the optical pulse with the first wavelength and the optical pulse with the second wavelength, and to determine dispersion in the optical transmission path.

In patent no. 8,843,335, a method and apparatus are provided for the removal of significant broad-band noise from waveforms acquired for time domain network analysis. The method may include the steps of providing the noisy waveform as an input waveform, determining a frequency domain noise shape associated with the input waveform, calculating a wavelet domain noise shape from the frequency domain noise shape, calculating a discrete wavelet transform of the input waveform to form a wavelet domain waveform, and estimating the noise statistics from the wavelet domain waveform. A threshold may be calculated from the estimated noise statistics and the wavelet domain noise shape, and the threshold may be applied to the wavelet domain waveform to form a denoised wavelet domain waveform. Finally, an inverse discrete wavelet transform of the denoised wavelet domain waveform may be calculated to form a denoised waveform.

In patent no. 8,842,920 systems and methods for facilitating video fingerprinting are provided. In one embodiment, a system can include: a memory, a microprocessor, a communication component that receives the media; and a media fingerprinting component that fingerprints the media. The media fingerprinting component employs a fingerprint generation component stored in the memory and includes: a wavelet transform generation component that computes a wavelet transform, and identifies a set of largest coefficients for, the frame information; a coefficient encoder component that encodes the largest coefficients by mapping the largest coefficients to a tuple of integers; an aggregation component that aggregates the tuples of integers, and records a count of the tuples. The MFC can also include: a weighted set generation component that generates a weighted set of the tuples of integers; and a hash generation component that generates a hash based on the weighted set of the tuples of integers.

If you have an interesting patent to share when we next feature patents related to Wavelet analysis techniques, or if you are especially interested in a signal processing research field that you would want to be highlighted in this section, please send email to Csaba Benedek (benedek.csaba AT sztaki DOT mta DOT hu).

References

Number: 8,990,053
Title:  Method of wavelet estimation and multiple prediction in full wavefield inversion  
Inventors:  S. Lazaratos and K. Wang
Issued:  March 24, 2015
Assignee:  ExxonMobil Upstream Research Company (Houston, TX)

Number: 8,989,509
Title: Streaming wavelet transform
Inventors:  A.C. Kuo, J.E. Frederiksen and M. Frank
Issued:  March 24, 2015
Assignee:  Apple Inc. (Cupertino, CA)

Number: 8,981,971
Title: Wavelet-based seismic data compression
Inventors:  Q. Liao, F. Gao and C. Rivera
Issued:  Total E&P Research & Technology USA, Inc. (Houston, TX)
Assignee:  March 17, 2015

Number: 8,977,067
Title: Audio identification using wavelet-based signatures
Inventors: S. Baluja and M. Covell
Issued:  March 10, 2015
Assignee:  Google Inc. (Mountain View, CA)

Number: 8,954,127
Title: Systems and methods for estimating values of a continuous wavelet transform
Inventors:  J.N. Watson, P.S. Addison and B.M. Van Slyke
Issued:  February 10, 2015
Assignee: Nellcor Puritan Bennett Ireland (Galway, IE)

Number: 8,885,974
Title: Method and associated system for synchronous wavelet transformation for massive multidimensional data
Inventors:  M. Antonini and A. Meftah
Issued:  November 11, 2014
Assignee:  Centre National de la Recherche Scientifique--CNRS (Paris, FR)

Number: 8,848,976
Title: Method for tracking parametric motion of an area using complex discrete wavelet transform
Inventors:  S. Yilmaz
Issued:  September 30, 2014
Assignee:  Aselsan Elektronik Sanayi Ve Ticaret Anonim Sirketi (Ankara, TR)

Number: 8,848,176
Title: Dispersion measurement apparatus using a wavelet transform to determine a time difference based on indentified peaks
Inventors:  M. Sekiya and Y. Yamamoto
Issued: September 30, 2014
Assignee:  Fujitsu Limited (Kawasaki, JP)

Number: 8,843,335
Title: Wavelet denoising for time-domain network analysis
Inventors:  P.J. Pupalaikis, A. Sureka and K. Doshi
Issued: September 23, 2014
Assignee: Teledyne LeCroy, Inc. (Thousand Oaks, CA)

Number: 8,842,920
Title: Systems and methods for facilitating crop-invariant video fingerprinting using wavelet transforms
Inventors: S. Ioffe
Issued: September 23, 2014
Assignee:  Google Inc. (Mountain View, CA)