function?[sift_arr?grid_x?grid_y]?=?dense_sift（I?grid_spacing?patch_size）
%?Adapted?by?Antonio?Torralba:?modified?using?convolutions?to?speed?up?the?computations.
%?And?brought?back?into?Svetlana‘s?library

if（~exist（‘grid_spacing‘‘var‘））
????grid_spacing?=?1;
end
if（~exist（‘patch_size‘‘var‘））
????patch_size?=?16;
end

I?=?double（I）;
I?=?mean（I3）;
I?=?I?/max（I（:））;

%?parameters
num_angles?=?8;
num_bins?=?4;
num_samples?=?num_bins?*?num_bins;
alpha?=?9;?%%?parameter?for?attenuation?of?angles?（must?be?odd）

if?nargin?????sigma_edge?=?1;
end

angle_step?=?2?*?pi?/?num_angles;
angles?=?0:angle_step:2*pi;
angles（num_angles+1）?=?[];?%?bin?centers

[hgt?wid]?=?size（I）;

[G_XG_Y]=gen_dgauss（sigma_edge）;

%?add?boundary:
I?=?[I（2:-1:1::）;?I;?I（end:-1

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????文件????????4715??2013-03-29?20:06??dense_sift.m