Scale-Based Description and Recognition of Planar Curves and Two-Dimensional Shapes
IEEE Transactions on Pattern Analysis and Machine Intelligence
Detecting partially occluded ellipses using the Hough transform
Image and Vision Computing - 4th Alvey Vision Meeting
CVGIP: Image Understanding
A Comparative Evaluation of Length Estimators of Digital Curves
IEEE Transactions on Pattern Analysis and Machine Intelligence
Canonical representations of discrete curves
Pattern Analysis & Applications
Projective Estimators for Point/Tangent Representations of Planar Curves
SIBGRAPI '08 Proceedings of the 2008 XXI Brazilian Symposium on Computer Graphics and Image Processing
Comparison and improvement of tangent estimators on digital curves
Pattern Recognition
Tangential cover for thick digital curves
Pattern Recognition
Curvature and torsion estimators based on parametric curve fitting
Computers and Graphics
Robust estimation of curvature along digital contours with global optimization
DGCI'08 Proceedings of the 14th IAPR international conference on Discrete geometry for computer imagery
Experimental comparison of continuous and discrete tangent estimators along digital curves
IWCIA'08 Proceedings of the 12th international conference on Combinatorial image analysis
Error Analysis of Geometric Ellipse Detection Methods Due to Quantization
PSIVT '10 Proceedings of the 2010 Fourth Pacific-Rim Symposium on Image and Video Technology
Edge curvature and convexity based ellipse detection method
Pattern Recognition
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In this paper, we address the problem of tangent estimation for digital curves. We propose a simple, geometry based tangent estimation method for digital curves. The geometrical analysis of the method and the maximum error analysis for digital elliptic curves are presented. Numerical results have been tested for digital ellipses of various eccentricities (circle to very sharp ellipses) and the maximum error of the proposed method is bounded and is less than 5.5 degrees for reasonably large ellipses. The error for digital circles is also analyzed and compared with a recent tangent estimation method. In addition, the tangent estimation technique is applied to a flower shaped digital curve with six inflexion points and the results demonstrate good performance. The proposed tangent estimator is applied to a practical application which analyzes the error in a geometric ellipse detection method. The ellipse detection method is greatly benefited by the proposed tangent estimator, as the maximum error in geometrical ellipse detection is no more critically dependent upon the tangent estimation (due to the reduced error in tangent estimation). The proposed tangent estimator also increases the reliability and precision of the ellipse detection method.