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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd"><html><head> <title>Description of makeGaborFilter</title> <meta name="keywords" content="makeGaborFilter"> <meta name="description" content="makeGaborFilter - returns a 3d stack of 2d Gabor filters for each phase."> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <meta name="generator" content="m2html © 2003 Guillaume Flandin"> <meta name="robots" content="index, follow"> <link type="text/css" rel="stylesheet" href="../m2html.css"></head><body><a name="_top"></a><div><a href="../index.html">Home</a> > <a href="#">mfiles</a> > makeGaborFilter.m</div><!--<table width="100%"><tr><td align="left"><a href="../index.html"><img alt="<" border="0" src="../left.png"> Master index</a></td><td align="right"><a href="index.html">Index for .\mfiles <img alt=">" border="0" src="../right.png"></a></td></tr></table>--><h1>makeGaborFilter</h1><h2><a name="_name"></a>PURPOSE <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2><div class="box"><strong>makeGaborFilter - returns a 3d stack of 2d Gabor filters for each phase.</strong></div><h2><a name="_synopsis"></a>SYNOPSIS <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2><div class="box"><strong>function filter = makeGaborFilter(gaborParams, angle, varargin) </strong></div><h2><a name="_description"></a>DESCRIPTION <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2><div class="fragment"><pre class="comment"> makeGaborFilter - returns a 3d stack of 2d Gabor filters for each phase. filter = makeGaborFilter(gaborParams, angle, makeDisk) Returns a two-dimensional Gabor filter with the parameter: gaborParams - a struct with the following fields: filterPeriod - the period of the filter in pixels, elongation - the ratio of length versus width, filterSize - the size of the filter in pixels, stddev - the standard deviation of the Gaussian envelope in pixels. phases - the phase angles to be used. angle - the angle of orientation, in degrees, makeDisk - if 1, enforce a disk-shaped filter, i.e. set all values outside of a circle with diameter gaborParams.filterSize to 0. filter = makeGaborFilter(gaborParams, angle) Returns a two-dimensional Gabor filter, assuming makeDisk = 0. See also <a href="gaborFilterMap.html" class="code" title="function resultMap = gaborFilterMap(map,gaborParams,angle)">gaborFilterMap</a>, <a href="defaultSaliencyParams.html" class="code" title="function params = defaultSaliencyParams(varargin)">defaultSaliencyParams</a>.</pre></div><!-- crossreference --><h2><a name="_cross"></a>CROSS-REFERENCE INFORMATION <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2>This function calls:<ul style="list-style-image:url(../matlabicon.gif)"></ul>This function is called by:<ul style="list-style-image:url(../matlabicon.gif)"><li><a href="gaborFilterMap.html" class="code" title="function resultMap = gaborFilterMap(map,gaborParams,angle)">gaborFilterMap</a> gaborFilterMap - compute a gabor-filtered version of a map.</li></ul><!-- crossreference --><h2><a name="_source"></a>SOURCE CODE <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2><div class="fragment"><pre>0001 <span class="comment">% makeGaborFilter - returns a 3d stack of 2d Gabor filters for each phase.</span>0002 <span class="comment">%</span>0003 <span class="comment">% filter = makeGaborFilter(gaborParams, angle, makeDisk)</span>0004 <span class="comment">% Returns a two-dimensional Gabor filter with the parameter:</span>0005 <span class="comment">% gaborParams - a struct with the following fields:</span>0006 <span class="comment">% filterPeriod - the period of the filter in pixels,</span>0007 <span class="comment">% elongation - the ratio of length versus width,</span>0008 <span class="comment">% filterSize - the size of the filter in pixels,</span>0009 <span class="comment">% stddev - the standard deviation of the Gaussian envelope in pixels.</span>0010 <span class="comment">% phases - the phase angles to be used.</span>0011 <span class="comment">% angle - the angle of orientation, in degrees,</span>0012 <span class="comment">% makeDisk - if 1, enforce a disk-shaped filter, i.e. set all values</span>0013 <span class="comment">% outside of a circle with diameter gaborParams.filterSize to 0.</span>0014 <span class="comment">%</span>0015 <span class="comment">% filter = makeGaborFilter(gaborParams, angle)</span>0016 <span class="comment">% Returns a two-dimensional Gabor filter, assuming makeDisk = 0.</span>0017 <span class="comment">%</span>0018 <span class="comment">% See also gaborFilterMap, defaultSaliencyParams.</span>0019 0020 <span class="comment">% This file is part of the SaliencyToolbox - Copyright (C) 2006-2007</span>0021 <span class="comment">% by Dirk B. Walther and the California Institute of Technology.</span>0022 <span class="comment">% See the enclosed LICENSE.TXT document for the license agreement.</span>0023 <span class="comment">% More information about this project is available at:</span>0024 <span class="comment">% http://www.saliencytoolbox.net</span>0025 0026 <a name="_sub0" href="#_subfunctions" class="code">function filter = makeGaborFilter(gaborParams, angle, varargin)</a>0027 0028 <span class="keyword">if</span> isempty(varargin)0029 makeDisk = 0;0030 <span class="keyword">else</span>0031 makeDisk = varargin{1};0032 <span class="keyword">end</span>0033 0034 <span class="comment">% repare parameters</span>0035 major_stddev = gaborParams.stddev;0036 minor_stddev = major_stddev * gaborParams.elongation;0037 max_stddev = max(major_stddev,minor_stddev);0038 0039 sz = gaborParams.filterSize;0040 <span class="keyword">if</span> (sz == -1)0041 sz = ceil(max_stddev*sqrt(10));0042 <span class="keyword">else</span>0043 sz = floor(sz/2); 0044 <span class="keyword">end</span>0045 0046 rtDeg = pi / 180 * angle;0047 0048 omega = 2 * pi / gaborParams.filterPeriod;0049 co = cos(rtDeg);0050 si = -sin(rtDeg);0051 major_sigq = 2 * major_stddev^2;0052 minor_sigq = 2 * minor_stddev^2;0053 0054 <span class="comment">% prepare grids for major and minor components</span>0055 vec = [-sz:sz];0056 vlen = length(vec);0057 vco = vec*co;0058 vsi = vec*si;0059 0060 major = repmat(vco',1,vlen) + repmat(vsi,vlen,1);0061 major2 = major.^2;0062 minor = repmat(vsi',1,vlen) - repmat(vco,vlen,1);0063 minor2 = minor.^2;0064 0065 phase0 = exp(- major2 / major_sigq - minor2 / minor_sigq);0066 0067 <span class="comment">% create the actual filters</span>0068 <span class="keyword">for</span> p = 1:length(gaborParams.phases)0069 psi = pi / 180 * gaborParams.phases(p);0070 result = cos(omega * major + psi) .* phase0;0071 0072 <span class="comment">% enforce disk shape?</span>0073 <span class="keyword">if</span> (makeDisk)0074 result((major2+minor2) > (gaborParams.filterSize/2)^2) = 0;0075 <span class="keyword">end</span>0076 0077 <span class="comment">% normalization</span>0078 result = result - mean(result(:));0079 filter(:,:,p) = result / sqrt(sum(result(:).^2));0080 <span class="keyword">end</span></pre></div><hr><address>Generated on Fri 07-Sep-2007 14:42:18 by <strong><a href="http://www.artefact.tk/software/matlab/m2html/">m2html</a></strong> © 2003</address></body></html>⌨️ 快捷键说明
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