Momocs (version 1.4.1)

symmetry: Calcuates symmetry indices on OutCoe objects

Description

For OutCoe objects obtained with efourier, calculates several indices on the matrix of coefficients: AD, the sum of absolute values of harmonic coefficients A and D; BC same thing for B and C; amp the sum of the absolute value of all harmonic coefficients and sym which is the ratio of AD over amp. See references below for more details.

Usage

symmetry(OutCoe)

Value

a matrix with 4 colums described above.

Arguments

OutCoe

efourier objects

References

Below: the first mention, and two applications.

• Iwata, H., Niikura, S., Matsuura, S., Takano, Y., & Ukai, Y. (1998). Evaluation of variation of root shape of Japanese radish (Raphanus sativus L.) based on image analysis using elliptic Fourier descriptors. Euphytica, 102, 143-149.

• Iwata, H., Nesumi, H., Ninomiya, S., Takano, Y., & Ukai, Y. (2002). The Evaluation of Genotype x Environment Interactions of Citrus Leaf Morphology Using Image Analysis and Elliptic Fourier Descriptors. Breeding Science, 52(2), 89-94. doi:10.1270/jsbbs.52.89

• Yoshioka, Y., Iwata, H., Ohsawa, R., & Ninomiya, S. (2004). Analysis of petal shape variation of Primula sieboldii by elliptic fourier descriptors and principal component analysis. Annals of Botany, 94(5), 657-64. doi:10.1093/aob/mch190

See Also

rm_asym and rm_sym.

Examples

bot.f <- efourier(bot, 12)
res <- symmetry(bot.f)
hist(res[, 'sym'])