Pyramid (image processing): Difference between revisions

Revision as of 04:19, 8 May 2017

Revision as of 14:21, 26 June 2017

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| pmid = 21869180

| doi = 10.1109/TPAMI.1984.4767500

}}</ref><ref>{{cite journal | last1 = Crowley | first1 = J. L. | last2 = Sanderson | first2 = A. C. | year = 1987 | title = Multiple resolution representation and probabilistic matching of 2-D gray-scale shape | url = http://www-prima.inrialpes.fr/Prima/Homepages/jlc/papers/Crowley-Sanderson-PAMI87.pdf| journal = IEEE Transactions on Pattern Analysis and Machine Intelligence | volume = 9 | issue = 1| pages = 113–121 }}</ref><ref>{{cite journal | last1 = Meer | first1 = P. | last2 = Baugher | first2 = E. S. | last3 = Rosenfeld | first3 = A. | year = 1987 | title = Frequency ___domain analysis and synthesis of image generating kernels | url = | journal = IEEE Transactions on Pattern Analysis and Machine Intelligence | volume = 9 | issue = | pages = 512–522 }}</ref> Among the suggestions that have been given, the ''binomial kernels'' arising from the [[binomial coefficient]]s stand out as a particularly useful and theoretically well-founded class.<ref name=Crowley1981/><ref>Lindeberg, Tony, "[http://www.nada.kth.se/~tony/abstracts/Lin90-PAMI.html Scale-space for discrete signals]," PAMI(12), No. 3, March 1990, pp. 234-254.</ref><ref>Lindeberg, Tony. [http://www.nada.kth.se/~tony/book.html Scale-Space Theory in Computer Vision], Kluwer Academic Publishers, 1994, {{ISBN |0-7923-9418-6}} (see specifically Chapter 2 for an overview of Gaussian and Laplacian image pyramids and Chapter 3 for theory about generalized binomial kernels and discrete Gaussian kernels)</ref><ref>See the article on [[multi-scale approaches]] for a very brief theoretical statement</ref> Thus, given a two-dimensional image, we may apply the (normalized) binomial filter (1/4, 1/2, 1/4) typically twice or more along each spatial dimension and then subsample the image by a factor of two. This operation may then proceed as many times as desired, leading to a compact and efficient multi-scale representation. If motivated by specific requirements, intermediate scale levels may also be generated where the subsampling stage is sometimes left out, leading to an ''oversampled'' or ''hybrid pyramid''.<ref name=LinBre03-ScSp/> With the increasing computational efficiency of [[CPU]]s available today, it is in some situations also feasible to use wider support [[Gaussian filter]]s as smoothing kernels in the pyramid generation steps.

===Gaussian pyramid===