Maarten Van Ginkel

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We propose a new curvature estimator, which operates on the output of an orientation estimator. Robust orientation estimators have been available for a long time. Some properties of the estimator as well as potential problems and limitations are discussed. The theory is verified by some experiments and practical limitations are investigated. The method is(More)
Filtering of an image with rotated versions of an orientation selective filter yields a set of images which can be stacked to form an orientation space. Orientation space provides a means of analyzing overlapping and touching patterns, characterized by their orientation. In this paper we extend previous work and show that curved patterns may also be(More)
Extraction of primitives, such as lines, edges and curves, is often a key step in an image analysis procedure. The most popular technique for curve detection is based on the Hough transform. The original formulation of the Hough transform is inherently discrete. It is therefore difficult to assess which properties are inherent to the transform-based(More)
pedigree/bulk method (MODPED) (van Ginkel et al., 2002), which successfully produced many of the widely Breeding strategies used by plant breeders are many and varied, adapted wheats now being grown in the developing making it difficult to compare efficiencies of different breeding strate-world. This method was replaced in the late 1990s by gies through(More)
There are large agricultural areas in the world where wheat yields are limited by low phosphorus (P) availability. Breeding for P uptake and P utilization efficiency may reduce this problem. This study was conducted to determine the contribution of P uptake and utilization efficiency to grain yield of selected spring wheat genotypes in different(More)
We present a novel approach to parameterised curve detection. The method is based on the generalised Radon transform, which is traditionally applied to a 2D edge/line map. The novelty of our method is the mapping of the original 2D image to a 3D orientation space, which then forms the input for the Radon transform. The orientation space representation(More)
Filtering of an image with rotated versions of an orientation selective filter yields a set of images which can be stacked to form an orientation space. Orientation space provides a means of analyzing overlapping and touching anisotropic textures. A set of rotated k th order directional derivatives yields a discrete orientation space, which allows(More)
We have developed a new, robust, curvature esti-mator. It is based on " fitting " circular segments to a curve using a generalised Radon transform. The key step in the approach is that the fitting operation is not done in the original image, but in a transformed version, called Orientation Space. The original curve is transformed into another curve in(More)