Momocs (version 1.0.0)

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)

Arguments

OutCoe

[efourier] objects

Value

a matrix with 4 colums described above.

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

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