<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>The magnitude-based Fourier descriptors (FD) are frequently used in shape-based image retrieval, due to their efficiency and effectiveness. Unlike the phase-preserving Fourier descriptors, the magnitude-based Fourier descriptors are inherently invariant under rotation and starting point change, but they discard all valuable information contained in the phase of the Fourier coefficients (FCs). In order to preserve the coefficients’ phase, the orientation and starting point of the shape must be determined. In this paper, we conducted a comprehensive evaluation of different state-of-the-art methods for determining nominal shape orientation, which can be used to extract phase-preserving Fourier descriptors: the point of maximal radius, the axis of least inertia (moments), the phase of the first harmonic, the cross-correlation, the Procrustes distance and the pseudomirror points. The methods were compared in terms of sensitivity to non-rigid transformations, retrieval performance, computational complexity and computational time. The experimental results give insight into the pros and cons of all analyzed methods.</p>
</abstract>

The magnitude-based Fourier descriptors (FD) are frequently used in shape-based image retrieval, due to their efficiency and effectiveness. Unlike the phase-preserving Fourier descriptors, the magnitude-based Fourier descriptors are inherently invariant under rotation and starting point change, but they discard all valuable information contained in the phase of the Fourier coefficients (FCs). In order to preserve the coefficients’ phase, the orientation and starting point of the shape must be determined. In this paper, we conducted a comprehensive evaluation of different state-of-the-art methods for determining nominal shape orientation, which can be used to extract phase-preserving Fourier descriptors: the point of maximal radius, the axis of least inertia (moments), the phase of the first harmonic, the cross-correlation, the Procrustes distance and the pseudomirror points. The methods were compared in terms of sensitivity to non-rigid transformations, retrieval performance, computational complexity and computational time. The experimental results give insight into the pros and cons of all analyzed methods.

A Comprehensive Study of Shape Orientation Methods for Extraction of Phase-Preserving Fourier Descriptors

B&H Electrical Engineering

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

The magnitude-based Fourier descriptors (FD) are frequently used in shape-based image retrieval, due to their efficiency and effectiveness. Unlike the...

A Comprehensive Study of Shape Orientation Methods for Extraction of Phase-Preserving Fourier Descriptors

Published Online: Nov 07, 2022

Page range: 71 - 79

Received: Oct 01, 2019

Accepted: Nov 01, 2019

DOI: https://doi.org/10.2478/bhee-2019-0009

Keywords
Fourier descriptors, image retrieval, shape description, nominal shape orientation, reference points

© 2019 Emir Sokić et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

A Comprehensive Study of Shape Orientation Methods for Extraction of Phase-Preserving Fourier Descriptors

Published Online: Nov 07, 2022

Page range: 71 - 79

Received: Oct 01, 2019

Accepted: Nov 01, 2019

DOI: https://doi.org/10.2478/bhee-2019-0009

KeywordsFourier descriptors, image retrieval, shape description, nominal shape orientation, reference points

© 2019 Emir Sokić et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
Fourier descriptors, image retrieval, shape description, nominal shape orientation, reference points