FINDIMPORTANTEXTREMA1D - Find important extrema of 1D signal.

Contents

Description

Find strict extrema in (1D) time series and compute their importance using the approach of [FG07].

Syntax

    [Extrema, Strict, Left, Right] = findimportantextrema1D(X);
    [Extrema, Strict, Left, Right] = findimportantextrema1D(X, dist);

Reference

[FG07] E. Fink and H.S.Gandhi: "Important extrema of time series", Proc. IEEE International Conference on Systems, Man, and Cybernetics, pp. 366-372, 2007.

See also

Ressembles: FINDZEROEXTREMA1D. Requires: FINDZEROEXTREMA1D_BASE.

Function implementation

function [Extrema, Strict, Left, Right] = findimportantextrema1D(X, varargin)

parsing parameters

error(nargchk(1, 15, nargin, 'struct'));
error(nargoutchk(0, 3, nargout, 'struct'));

% mandatory parameter
if ~isnumeric(X) || nb_dims(X)~=1
    error('findimportantextrema1D:inputerror','a 1D signal is required in input');
end

% optional parameters
p = createParser('FINDIMPORTANTEXTREMA1D');   % create an instance of the inputParser class.
p.addOptional('dist', 'abs', @(x) ischar(x) && any(strcmpi(x,{'abs','nabs'})));

% parse and validate all input arguments
p.parse(varargin{:});
p = getvarParser(p);

main computation

[Extrema, Strict, Left, Right] = findimportantextrema1D_base(X, p.dist);

display

if p.disp
    figure, hold on;
    plot(X,'-kx');  plot(Extrema(:,1), Extrema(:,2), 'ro');
    text(Extrema(:,1), Extrema(:,2), num2str(Strict), 'VerticalAlignment','top','Color','r');
    title('extrema''s strict importance');  hold off;
end

end % end of findimportantextrema1D