The manner by which the short line segments are connected to approximate the ideal straight line in digital image space will influence the performance of Hough transform. The peak spreading can be avoided when Delta r...
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The manner by which the short line segments are connected to approximate the ideal straight line in digital image space will influence the performance of Hough transform. The peak spreading can be avoided when Delta rho satisfies a certain condition. Consequently, a new approach called a variable-Delta rho Hough transform having Delta rho as a function of theta is proposed. For the probabilistic Hough transforms (PHT) it is shown that although one of their advantages is the ability to avoid direct quantization of parameter space but the influence of the discretization in image space becomes more serious. To avoid this problem, a suitable tolerance parameter delta as a function of rho and theta is required. (C) 1999 Pattern Recognition Society. Published by Elsevier Science Ltd. All rights reserved.
We investigate hidden symmetries of a P,T-invariant system of topologically massive U(1) gauge fields. For this purpose we propose a pseudoclassical model giving rise to this field system at the quantum level. The mod...
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We investigate hidden symmetries of a P,T-invariant system of topologically massive U(1) gauge fields. For this purpose we propose a pseudoclassical model giving rise to this field system at the quantum level. The model contains a parameter which displays a quantization property at the classical and the quantum levels and demonstrates a non-trivial relationship between continuous and discrete symmetries. Analyzing the integrals of motion of the pseudoclassical model, we identify the U(1,1) symmetry and the S(2,1) supersymmetry as hidden symmetries of the corresponding quantum system. Representing the hidden symmetries in a covariant form, we show that one-particle states realize an irreducible representation of a non-standard super-extension of the (2 + 1)-dimensional Poincare group labelled by the zero eigenvalue of the superspin. (C) 1998 Elsevier Science B.V.
The Hough Transform (HT) method has long been recognized as a promising detection technique for images containing noisy, missing, and extraneous data. However, its performance depends very much on the way the transfor...
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The Hough Transform (HT) method has long been recognized as a promising detection technique for images containing noisy, missing, and extraneous data. However, its performance depends very much on the way the transformed space, Hough space (HS), is quantized. Van Veen and Green (1981) derived formulae specifying the effect of peak spreading in Hough space H(theta, rho) for a line segment when neither oversampling nor undersampling occurs. But since then, no further investigations on other parametric curves were mentioned. In this paper, starting from the point of view of uncertainty incurred in the parameter sampling and quantization, we study its effect on the formation of peaks in the Hough space. In addition, relations between sampling intervals and quantizing intervals for line segments and circles are derived which can serve as a guideline to achieve optimal quantization. For line segments, we arrive at the same result as in (Van Veen and Green, 1981). Moreover, our approach can also be applied to other parametric curves.
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