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Harmonic wavelet transform

About: Harmonic wavelet transform is a research topic. Over the lifetime, 9602 publications have been published within this topic receiving 247336 citations.


Papers
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Proceedings ArticleDOI
27 Dec 2003
TL;DR: Two methods for face recognition problem with an image database, based on face-based approach, combine the wavelet transform and fast Fourier transform and discrete cosine transform to extract the most insensitive features to facial expression variations.
Abstract: This paper describes two methods for face recognition problem with an image database (DB) The two methods are based on face-based approach The first method combines the wavelet transform (WT) and fast Fourier transform (FFT), while the second method, combine the WT and discrete cosine transform (DCT) Using the virtue of WT we extract the most insensitive features to facial expression variations The first method is proven to be very efficient with face images of different features, illuminations and small occlusion The second method has proven to be good with the above variations of first method together with face images of different: scales, poses and rotated images (plusmn20) Two DBs are used to perform our work The Yale DB and Olivetti DB The two introduced methods are compared to two known methods, the template method and the eigenface method on the same DBs

51 citations

Journal ArticleDOI
TL;DR: Frick et al. as discussed by the authors proposed a modified continuous wavelet transform for spectral analysis of data with gaps, which is based on a family of functions called "gapped wavelets" which fulfill the admissibility condition on the gapped support.
Abstract: A recently introduced algorithm [Frick et al., Astrophys. J. 483, 426 (1997)] of spectral analysis of data with gaps via a modified continuous wavelet transform is developed and studied. This algorithm is based on a family of functions called "gapped wavelets" which fulfill the admissibility condition on the gapped support. The wavelet family is characterized by an additional parameter which should be calculated for every scale and position. Three theorems concerning the properties of gapped wavelet transform are formulated and proved. They affirm the global stability of the algorithm as well as its stability in both limits of large and small scales. These results are illustrated by some numerical examples, which show that the algorithm really attenuates the artifacts coming from gaps (and/or boundaries), and is particularly efficient at small and large scales.

51 citations

Journal ArticleDOI
TL;DR: Alternative methods for the estimation of spectra are described and compared and general questions of statistical variability, the use of regression methods to smooth the periodogram, and use of time sectioning of the data to either smooth or to investigate non-stationarities in the data are discussed.

51 citations

Journal ArticleDOI
TL;DR: A novel ridge extraction algorithm for use with the two-dimensional continuous wavelet transform to extract the phase information from a fringe pattern is presented and it is found to be robust and reliable.
Abstract: We present a novel ridge extraction algorithm for use with the two-dimensional continuous wavelet transform to extract the phase information from a fringe pattern. A cost function is employed for the detection of the ridge. The results of the proposed algorithm on simulated and real fringe patterns are illustrated. Moreover, the proposed algorithm outperforms the maximum ridge extraction algorithm and it is found to be robust and reliable.

51 citations

Journal ArticleDOI
TL;DR: A new linear integral transform is defined, which is called the exponential chirp transform, which provides frequency domain image processing for space-variant image formats, while preserving the major aspects of the shift-invariant properties of the usual Fourier transform.
Abstract: Space-variant (or foveating) vision architectures are of importance in both machine and biological vision. In this paper, we focus on a particular space-variant map, the log-polar map, which approximates the primate visual map, and which has been applied in machine vision by a number of investigators during the past two decades. Associated with the log-polar map, we define a new linear integral transform, which we call the exponential chirp transform. This transform provides frequency domain image processing for space-variant image formats, while preserving the major aspects of the shift-invariant properties of the usual Fourier transform. We then show that a log-polar coordinate transform in frequency provides a fast exponential chirp transform. This provides size and rotation, in addition to shift, invariant properties in the transformed space. Finally, we demonstrate the use of the fast exponential chirp algorithm on a database of images in a template matching task, and also demonstrate its uses for spatial filtering.

51 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202323
202274
20213
20207
20196
201831