apply_filter            Apply a filter constructed with build_filter
arclength               Calculate arc length along a 2D curve
build_filter            Constructs a smoothing filter
curvature               Estimates curvature for a single curve
deriv                   Estimate first or second derivatives for dy/dx.
find_gaps_df            Find gaps in a data series
fishwidth               Fish body width profiles
get_body_cycle_numbers_df
                        Gets oscillation cycle numbers for a midline
                        data set
get_cycle_numbers       Gets cycle numbers from a phase variable
get_frequency           Estimates the cycle frequency based on time and
                        phase
get_midline_center_df   Gets the center of a midline for many midlines
                        in a data frame
get_primary_swimming_axis
                        Gets the main swimming axis from a midline
get_primary_swimming_axis_df
                        Gets the primary swimming axis for many
                        midlines
get_volume              Gets the volume of segments of a cylindrical
                        body with elliptical cross section
get_wavelength          Computes the body wavelength based on the phase
                        at each point and the arc length
hilbert_phase           Compute phase of an oscillation using the
                        Hilbert transform
interpolate_peak_location
                        Interpolate the location of a peak based on
                        three points
interpolate_points_df   Interpolates and smooths a 2D curve at new arc
                        length
interpolate_points_frame
                        Interpolates x and y points on a curve to
                        different arc lengths
interpolate_width       Interpolates and scales fish body width
lampreydata             Lamprey midline data
peak_phase              Compute phase of an oscillation by locating
                        peaks and zero crossings.
pivot_kinematics_longer
                        Pivots a kinematics dataset into long format
skip_na                 Skip NAs when running a function on a vector
smooth_point            Applies a smoothing spline to a data series,
                        potentially with gaps
smooth_points_df        Smooths locations of points over time
xmucosusdata            Prickleback tracking data
zebrafish_shape         Zebrafish body shape
zfish_goodframes        Zebrafish good frame ranges
zfishdata               Zebrafish keypoint tracking data
