Correct 180-degrees spurious rotation in closed outline shapes. Used internally.
rotate_fcoef(fcoef)Arguments
- fcoef
The set of Fourier coefficients measuring the shape(s) to be rotated.
Value
A set of Fourier coefficients describing the rotated outline(s).
References
Iwata, H., & Ukai, Y. (2002). SHAPE: a computer program package for quantitative evaluation of biological shapes based on elliptic Fourier descriptors. Journal of Heredity, 93(5), 384-385.
Examples
#load shells data, plot the first shape
data("shells")
shape1 <- shells$shapes$coe[1,]
plot(inv_efourier(shape1, 300))
#rotate and plot again
shape1_rot <- rotate_fcoef(shape1)
plot(inv_efourier(shape1_rot, 300))
