Struct efd::Efd

pub struct Efd<D: EfdDim> { /* private fields */ }

Elliptical Fourier Descriptor coefficients. Provide transformation between discrete points and coefficients.

Transformation

The transformation of normalized coefficients.

Implements Kuhl and Giardina method of normalizing the coefficients An, Bn, Cn, Dn. Performs 3 separate normalizations. First, it makes the data location invariant by re-scaling the data to a common origin. Secondly, the data is rotated with respect to the major axis. Thirdly, the coefficients are normalized with regard to the absolute value of A₁.

Please see Transform for more information.

Implementations

impl<D: EfdDim> Efd<D>

pub fn try_from_coeffs(coeffs: Array2<f64>) -> Result<Self, EfdError<D>>

Create object from a nx4 array with boundary check.

pub fn gate<C, T>(curve: C, threshold: T) -> Option<usize>where C: Curve<Coord<D>>, Option<f64>: From<T>,

Apply Nyquist Frequency on Fourier power analysis with a custom threshold value (default to 99.99%).

This method returns the minimum harmonic number to keep the shape features.

The threshold must in [0, 1). This function returns None if the curve length is less than 1.

let harmonic = efd::Efd2::gate(curve, None).unwrap();

pub fn from_curve<C>(curve: C) -> Option<Self>where C: Curve<Coord<D>>,

Calculate EFD coefficients from an existing discrete points.

The curve must be closed. (first == last)

Return none if the curve length is less than 1.

pub fn from_curve_gate<C, T>(curve: C, threshold: T) -> Option<Self>where C: Curve<Coord<D>>, Option<f64>: From<T>,

Calculate EFD coefficients from an existing discrete points and Fourier power gate.

The curve must be closed. (first == last)

Return none if the curve length is less than 1.

pub fn from_curve_harmonic<C, H>(curve: C, harmonic: H) -> Option<Self>where C: Curve<Coord<D>>, Option<usize>: From<H>,

Calculate EFD coefficients from a series of existing discrete points.

The curve must be closed. (first == last)

Return none if harmonic number is zero or the curve is less than two points.

If the harmonic number is not given, it will be calculated with Self::gate() function.

See also [closed_curve].

pub fn with_trans(self, trans: Transform<D::Trans>) -> Self

A builder method for changing transform type.

pub fn into_inner(self) -> Array2<f64>

Consume self and return a raw array of the coefficients.

pub fn coeffs(&self) -> ArrayView2<'_, f64>

Get the array view of the coefficients.

pub fn as_trans(&self) -> &Transform<D::Trans>

Get the reference of transform type.

pub fn as_trans_mut(&mut self) -> &mut Transform<D::Trans>

Get the mutable reference of transform type.

pub fn harmonic(&self) -> usize

Get the harmonic number of the coefficients.

pub fn square_err(&self, rhs: &Self) -> f64

Square error.

Panics

When the harmonic number is different.

pub fn l1_norm(&self, rhs: &Self) -> f64

L1 norm error, aka Manhattan distance.

Panics

When the harmonic number is different.

pub fn l2_norm(&self, rhs: &Self) -> f64

L2 norm error, aka Euclidean distance.

Panics

When the harmonic number is different.

pub fn lp_norm(&self, rhs: &Self, p: i32) -> f64

Lp norm error, slower than Self::l1_norm() and Self::l2_norm().

Panics

When the harmonic number is different.

pub fn reverse(&mut self) -> &mut Self

Reverse the order of described curve then return a mutable reference.

pub fn reversed(self) -> Self

Consume and return a reversed version of the coefficients. This method can avoid mutable require.

Please clone the object if you want to do self-comparison.

pub fn generate_norm(&self, n: usize) -> Vec<Coord<D>>

Generate the normalized curve without transformation.

The number of the points n must larger than 3.

pub fn generate(&self, n: usize) -> Vec<Coord<D>>

Generate the described curve from the coefficients.

The number of the points n must given.

Trait Implementations

impl<D: Clone + EfdDim> Clone for Efd<D>where D::Trans: Clone,

fn clone(&self) -> Efd<D>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.