function?stats?=?chip_histogram_features（?varargin?）
%?------------
%?Description:
%?------------
%??This?function?is?to?obtain?state?of?the?art?histogram?based?features
%?such?as:
%???Mean
%???Variance
%???Skewness
%???Kurtosis
%???Energy
%???Entropy
%?---------
%?History:
%?---------
%?Creation:?beta?????????Date:?09/11/2007
%----------
%?Example:
%----------
%?Stats?=?chip_histogram_features（?I‘NumLevels‘9‘G‘[]?）
%
%?-----------
%?Author:
%?-----------
%????（C）Xunkai?Wei?
%????Beijing?Aeronautical?Technology?Research?Center
%????Beijing?%9203-1210076
%

%?Parameter?checking
[I?NL?GL]?=?ParseInputs（varargin{:}）;
%?Scale?I?so?that?it?contains?integers?between?1?and?NL.
if?GL（2）?==?GL（1）
????SI?=?ones（size（I））;
else
????slope?=?（NL-1）?/?（GL（2）?-?GL（1））;
????intercept?=?1?-?（slope*（GL（1）））;
????SI?=?round（imlincomb（slopeIintercept‘double‘））;
end
%?Clip?values?if?user?had?a?value?that?is?outside?of?the?range?e.g.?double
%?image?=?[0?.5?2;0?1?1];?2?is?outside?of?[01].?The?order?of?the?following
%?lines?matters?in?the?event?that?NL?=?0.
SI（SI?>?NL）?=?NL;
SI（SI?%--------------------------------------------------------------------------
%?1.?Calculate?histogram?for?all?scaled?gray?level?from?1?to?NL
%--------------------------------------------------------------------------
%?Get?image?size
s?=?size（SI）;
%?Generate?gray?level?vector
Gray_vector?=?1:NL;
%?intialize?parameters
Histogram?=?zeros（1NL）;
%?Using?inline?function?numel?make?it?easy
for?i?=1:NL
????Histogram（i）?=?numel（find（SI==i））;
end
%--------------------------------------------------------------------------
%?2.?Now?calculate?its?histogram?statistics
%--------------------------------------------------------------------------
%?Calculate?obtains?the?approximate?probability?density?of?occurrence?of?the?intensity
%?levels
Prob????????????????=?Histogram./（s（1）*s（2））;
%?2.1?Mean?
Mean????????????????=?sum（Prob.*Gray_vector）;
%?2.2?Variance
Variance????????????=?sum（Prob.*（Gray_vector-Mean）.^2）;
%?2.3?Skewness
Skewness????????????=?calculateSkewness（Gray_vectorProbMeanVariance）;
%?2.4?Kurtosis
Kurtosis????????????=?calculateKurtosis（Gray_vectorProbMeanVariance）;
%?2.5?Energy
Energy??????????????=?sum（Prob.*Prob）;
%?2.6?Entropy
Entropy?????????????=?-sum（Prob.*log（Prob））;
%-------------------------------------------------------------------------
%?3.?Insert?all?features?and?return
%--------------------------------------------------------------------------
stats?=[Mean?Variance?Skewness?Kurtosis??Energy??Entropy];
%?End?of?funtion
%--------------------------------------------------------------------------
%?Utility?functions
%--------------------------------------------------------------------------
function?Skewness?=?calculateSkewness（Gray_vectorProbMeanVariance）
%?Calculate?Skewness
term1????=?Prob.*（Gray_vector-Mean）.^3;
term2????=?sqrt（Variance）;
Skewness?=?term2^（-3）*sum（term1）;

function?Kurtosis?=?calculateKurtosis（Gray_vectorProbMe

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----

?????文件???????5427??2008-09-16?21:24??chip_histogram_features.m

-----------?---------??----------?-----??----

?????????????????5427????????????????????1