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Issue No.11 - November (2001 vol.23)
pp: 1313-1329
ABSTRACT
<p><b>Abstract</b>—We show that a translation invariant implementation of min/max filters along a line segment of slope in the form of an irreducible fraction <tmath>$dy/dx$</tmath> can be achieved at the cost of <tmath>$2+k$</tmath> min/max comparisons per image pixel, where <tmath>$k=\max(|dx|,|dy|)$</tmath>. Therefore, for a given slope, the computation time is constant and independent of the length of the line segment. We then present the notion of periodic moving histogram algorithm. This allows for a similar performance to be achieved in the more general case of rank filters and rank-based morphological filters. Applications to the filtering of thin nets and computation of both granulometries and orientation fields are detailed. Finally, two extensions are developed. The first deals with the decomposition of discrete disks and arbitrarily oriented discrete rectangles, while the second concerns min/max filters along gray tone periodic line segments.</p>
INDEX TERMS
Image analysis, mathematical morphology, rank filters, directional filters, periodic line, discrete geometry, granulometry, orientation field, radial decomposition.
CITATION
Pierre Soille, Hugues Talbot, "Directional Morphological Filtering", IEEE Transactions on Pattern Analysis & Machine Intelligence, vol.23, no. 11, pp. 1313-1329, November 2001, doi:10.1109/34.969120