function [xf, nround] = softthreshold(x, epsilon)
% Soft threshold for a one or two dimensional signal
%       [xf, nround] = softthreshold(x, epsilon)
% 
% x is filtered according to the equation
%       xf(k) = sign( x(k) ) * ( |x(k)| - epsilon )
% Input parameters:
% x         Signal
% epsilon   Treshold value
% Output parameters:
% xf        The tresholded signal
% nround    Number of elements in xf that are zero.

nround = 0;
[N,M] = size(x);

% Thresholding
for n=1:N
    for m=1:M
        if abs(x(n,m)) < epsilon
            xf(n,m) = 0;
            nround = nround + 1;
        else
            xf(n,m) = sign( x(n,m) ) * ( abs(x(n,m)) - epsilon );
        end
    end
end