R/compute_rotation_between_frames.R

In Kneerav/biomechanics: Biomechanics Data Analysis

#' Compute Rotation Between Frames
#'
#' This function calculates the rotation matrix between corresponding frames in two 3D arrays.
#'
#' @param parent A 3-dimensional array where each slice represents a frame of rotation matrices.
#' @param child A 3-dimensional array of the same dimensions as `parent`, representing another set of rotation matrices.
#'
#' @return A 3-dimensional array of the same dimensions as `parent` and `child`, where each slice represents the rotation matrix between corresponding frames.
#' @export
compute_rotation_between_frames <- function(parent, child) {

  # Determine the number of frames
  n <- dim(parent)[3]

  # Initialize the result array
  c <- array(0, dim = dim(child))

  # Loop through each frame and calculate the rotation matrix
  for (i in 1:n) {
    c[,,i] <- child[,,i] %*% solve(parent[,,i])
  }

  return(c)
}