数字图像纹理特征提取代码

% Calculates cooccurrence matrix 
% for a given direction and distance
%
% out = cooccurrence （input dir dist symmetric）;
%
% INPUT:
% input: input matrix of any size
%
% dir: direction of evaluation
%       “dir“ value                    Angle
%              0                            0
%              1                           -45
%              2                           -90
%              3                           -135
%              4                           -180
%              5                           +135
%              6                           +90
%              7                           +45
%
% dist: distance between pixels
%
% symmetric:  1 for symmetric version
%                   0 for non-symmetric version
%
% eg: out = cooccurrence （