Shape retrieval using improved Arc-Height Function

Novel fourier descriptor based on complex coordinates shape signature

“…The retrieval performance is analyzed using precision and recall (PR) diagrams, a commonly adopted method in CBIR [8], [10], [12], [11]. Precision is defined as the ratio of the number of the relevant shapes to the total number of retrieved shapes, while recall is defined as the ratio of the number of retrieved relevant shapes to the total number of relevant shapes in the entire database.…”

“…The retrieval performance is tested on two shape databases, commonly used MPEG7 CE-1 Set B database [14], and Swedish leaf database used by Xu et al [12], showed in Figure 2 a) it includes rotation, scaling, skew, stretching, defection and indentation of shapes which may aid to test for robustness of the shape descriptors. The Swedish leaf database is freely available database generated by Linkoping University (http://www.isy.liu.se/cvl/ ImageDB/public/blad/), but preprocessed and binarized by Xu et al It has 15 species of leafs, with 75 leaves per species.…”

“…Five shape signatures will be used for comparison with our proposed method: 1) Complex coordinates signature (CC) [3], 978-1-4799-3990-9/14/$31.00 c 2014 IEEE 2) Radial/Centroid distance (RD) [8], 3) Farthest point distance (FPD) [10], 4) Combined perimeter area function (CPAF) [11], 5) Improved arc-height function (IARH) [12]. The first one is chosen since the proposed signature and descriptors are based on CC signature.…”

“…Fourier descriptors have been derived from several shape signatures: Complex coordinates, Centroid/Radial distance, Tangent angle [8], Curvature function, Area function, Trianglearea representation [9], Triangular centroid area, Chord length, Polar coordinates, Farthest point distance [10], Perimeter area function [11], Improved arc-height function [12], Rectangle centroid distance [13], and many others.…”

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

“…The scale invariance is achieved by dividing the FCs with the magnitude of the first harmonic [7], [8], [11], [12], or the sum of magnitudes of all harmonics [13], [14]. In order to obtain an invariance under rotation and starting point change, many authors discard the phase of the FCs and use only the magnitude of the FCs [7]- [9], [11], [13]. Due to this simplistic approach, valuable information about the shape is inevitably lost.…”