形状上下文

图像处理中非常热门的形状上下文描述子，用matlab与C++混合编程实现，打开后运行demo1或者demo2即可。

function [xytc]=bdry_extract_3（V）;
% [xytc]=bdry_extract_3（V）;
% compute （rtheta） histograms for points along boundary of single 
% region in binary image V 

% extract a set of boundary points w/oriented tangents
%sig=1;
%Vg=gauss_sig（Vsig）;
Vg=V; % if no smoothing is needed
c=contourc（Vg[.5 .5]）;
[G1G2]=gradient（Vg）;

% need to deal with multiple contours （for objects with holes）
fz=c（1:）~=0.5;
c（:find（~fz））=NaN;
B=c（:find（fz））;

npts=size（B2）;
t=zeros（npts1）;
for n=1:npts
   x0=round（B（1n））;
   y0=round（B（2n））;
   t（n）=atan2（G2（y0x0）G1（y0x0））+pi/2;
end

x=B（1:）‘;
y=B（2:）‘;

 属性            大小     日期    时间   名称
----------- ---------  ---------- -----  ----

     文件     965316  2005-06-13 09:29  shapecontext\2002shapematch-Belongie-Pami-ByContext.pdf

     文件        634  2000-09-04 23:51  shapecontext\bdry_extract_3.m

     文件        659  2000-09-04 20:28  shapecontext\bookstein.m

     文件      23891  2008-03-21 14:28  shapecontext\box1_5_coress.eps

     文件      34883  2008-03-21 14:28  shapecontext\box1_5_coress.fig

     文件      33970  2008-03-21 14:28  shapecontext\box1_5_trans.eps

     文件      18075  2008-03-21 14:28  shapecontext\box1_5_trans.fig

     文件      24026  2008-03-21 14:29  shapecontext\box1_9_coress.eps

     文件      35217  2008-03-21 14:29  shapecontext\box1_9_coress.fig

     文件      33929  2008-03-21 14:29  shapecontext\box1_9_trans.eps

     文件      18044  2008-03-21 14:29  shapecontext\box1_9_trans.fig

     文件       1154  2011-11-14 16:27  shapecontext\demo_1.m

     文件       1155  2000-09-05 15:00  shapecontext\demo_1.m~

     文件       8879  2000-09-25 21:16  shapecontext\demo_2.m

     文件       8879  2000-09-08 19:55  shapecontext\demo_2.m~

     文件     627576  2000-09-05 00:08  shapecontext\digit_100_train_easy.mat

     文件     627576  2000-09-05 00:08  shapecontext\digit_100_train_hard.mat

     文件        820  2000-09-04 20:26  shapecontext\dist2.m

     文件        115  2000-09-04 23:26  shapecontext\gaussker.m

     文件        577  2000-09-04 23:26  shapecontext\get_samples_1.m

     文件        432  2000-09-04 20:27  shapecontext\hist_cost_2.m

     文件      11250  2000-09-04 20:28  shapecontext\hungarian.m

     文件        335  2000-09-04 23:26  shapecontext\im.m

     文件         96  2008-03-21 14:28  shapecontext\main_box.m

     文件       1153  2008-03-21 14:25  shapecontext\main_shapecontext.m

     文件        874  2000-09-05 15:25  shapecontext\README

     文件       7288  2000-09-05 00:28  shapecontext\save_fish_def_3_1.mat

     文件       7288  2000-09-05 00:28  shapecontext\save_fish_noise_3_2.mat

     文件       8856  2000-09-05 00:28  shapecontext\save_fish_outlier_3_2.mat

     文件       1963  2000-09-05 15:20  shapecontext\sc_compute.m

............此处省略6个文件信息