Quantitative characterization of morphological polymorphism of handwritten characters loops

Size influence on shape of handwritten characters loops

“…of the surface and the first four Fourier amplitudes (A 1 -A 4 ) and phases (u 1 -u 4 a, d, o and q contours of each writer are summarized in Tables 1-4 (these statistics are given in [5] for the small loops). Since importance of enlargement could not be controlled, all the writers did not produced enlarged loops with a same increasing factor; on average, all letters and writers together, the ratio of surface between the enlarged and small loops amounted to 3.48 (Table 5), in reference to the surface values of the small loops given in [5].…”

“…On each one of five documents (see [5]), 13 individuals -those showing closed loops among a larger population of writers -were asked to write 10 times a series of alphabet letters in their usual way, and 3 times by increasing the size of their usual writing by a factor three. The total number of observations was 2325 for the small loops (591 a loops, 547 d loops, 596 o loops and 591 q loops) and 692 for the enlarged loops (162 a loops, 173 d loops, 173 o loops and 184 q loops).…”

“…Calculation of the surface enclosed in the loops, extraction of the skeletons of the handwritten loops, as well as size normalization of these skeletons and Fourier analysis of their shape, were carried out according to the methodology described in detail in [4,5]. Each contour (i.e.…”

“…In a first step, the shape between small and enlarged loops of letters a, d, o and q will be compared to determine if a global difference can be shown for each letter and each writer, in a population of writers; then, the various aspects of the shape which are represented by the first four pairs of Fourier descriptors [5] will be tested separately to show the ones which remain constant across change in size; finally, after testing if discrimination between writers is possible through analysis of enlarged loops, it will be www.elsevier.com/locate/forsciint Forensic Science International 172 (2007) [10][11][12][13][14][15][16] investigated if the enlarged and the small loops of one specific letter can be treated together when comparing handwritten documents of the same person.…”

Tek yumurta İkizlerinin El Yazılarının Adli Belge İncelemesi Açısından Değerlendirilmesi

“…Fourier yönteminin geçerliliğini inceleyen bir çalış-mada a, d, o ve q harflerinin benzerliği tespit etme bakımından önem derecesi incelenmiştir. İlk aşamada bu karakterlerin ayırt edici gücü tespit edilmiş ve d harfi en güçlü ayırt edici parametre olarak yüzde 82.4 oranıyla teyit edilmiştir (17). Çalışmamızda ikizlerin en çok benzer olarak kullandığı harfler sırası ile "d, b, v, y-z, u, a, ş, g, m" şeklinde tespit edilmiş olup, ikiz çiftlerin kullanmış oldukları harflerden; harflerin yapılış ve boyutları bakı-mından en fazla benzerlik gösteren harfin "d" harfi olduğu saptanmış ve 28 ikiz çiftin (%56) bu harfi benzer şekilde kullandığı saptanmıştır.…”