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Elastic Alignment for Functional Data

Source: R/alignment.R
srsf.transform.Rd

Functions for elastic curve alignment via SRSF transforms, Fisher-Rao distance, and Karcher mean computation. SRSF Transform

Usage

srsf.transform(fdataobj)

Arguments

fdataobj

An object of class 'fdata'.

Value

An object of class 'fdata' containing the SRSF-transformed curves.

Details

Compute the Square-Root Slope Function (SRSF) transformation of functional data: \(q(t) = \text{sign}(f'(t)) \sqrt{|f'(t)|}\).

References

Srivastava, A., Klassen, E., Joshi, S.H., and Jermyn, I.H. (2011). Shape analysis of elastic curves in Euclidean spaces. IEEE Transactions on Pattern Analysis and Machine Intelligence, 33(7):1415–1428.

Tucker, J.D., Wu, W., and Srivastava, A. (2013). Generative models for functional data using phase and amplitude separation. Computational Statistics & Data Analysis, 61:50–66.

Examples

fd <- fdata(matrix(rnorm(200), 20, 10), argvals = seq(0, 1, length.out = 10))
q <- srsf.transform(fd)