function?y?=?noise（varargin）
%??NOISE????Adds?noise?to?an?image.
%
%?????NOISE?creates?a?new?image?by?adding?noise?to?the?original?image.
%?????NOISE?can?be?used?to?any?matrix?（1D?2D?3D?nD）
%
%?????Noisetypes?are:
%???????‘ag‘?:?additive?gaussian?（default）????‘au‘?:?additive?uniform
%???????‘mg‘?:?multiplicative?gaussian????????‘mu‘?:?multiplicative?uniform
%???????‘sp‘?:?salt?and?pepper
%
%?????Additive?noise?sums?an?random?value?to?the?image?value?at?each?pixel
%?????Multiplicative?noise?replaces?a?pixel?value?with?an?random?value
%?????Salt?and?Pepper?noise?replaces?a?pixel?value?with?the?maximum?or?minimum?possible?values.
%
%?????For?‘ag‘?noisetype?use:??y?=?NOISE（x‘ag‘?variance?[incidence]）
%???????where?‘variance‘?is?the?variance?of?the?gaussian?noise?added?and?the?optional?parameter
%???????‘incidence‘?is?the?percetual?of?pixels?affected?be?the?noise?（default?for?additive?noise=1）.
%???????For?a?50%?incidence?use?‘incidence‘?=?.5?and?so?on.
%
%?????For?‘au‘?noisetype?use?:??y?=?NOISE（x‘au‘?maximum?[incidence]）
%???????where?‘maximum‘?is?the?maximum?value?the?uniform?noise?can?achieve
%
%?????For?‘mg‘?noisetype?use?:??y?=?NOISE（x‘mg‘?incidence）
%?????For?‘mu‘?noisetype?use?:??y?=?NOISE（x‘mu‘?incidence）
%???????Multiplicative?noisetypes?require?that?the?‘incidence‘?parameter.?For?this?kind?of?noise
%???????the?variance?or?the?maximum?（respectivelly?for?gaussian?and?uniform?noisetypes）?are?allways
%???????set?to?the?maximum?image?value.
%
%?????For?‘sp‘?noisetype?use?:??y?=?NOISE（x‘sp‘?incidence）
%
%?????The?‘maximum‘?and?‘variance‘?parameters?can?be?set?as?percentual?of?the?maximum?-?minimum?image?
%?????values?by?using?these?values?as?strings?containg?the?percentual?rate?followed?by?the?percent?symbol.
%?????The?‘incidence‘?can?also?be?expressed?as?a?pecentual?in?this?same?way
%
%?????Example:??y?=?NOISE（x‘ag‘?‘25%‘）
%???????????????y?=?NOISE（x‘mu‘?10?.5）?->?same?as?y?=?NOISE（x‘mu‘10?‘50%‘）
%

[u?noisetype??scale?incid]?=?parse_inputs（varargin{:}）;

if?~isa（u‘double‘）
???u?=?double（u）;
end

y?=?u;

n?=?zeros（size（u））;
if?incid?==?