calcAOIFixDensityDist

 calculate fixation density at the AOIs
 
 Syntax: [ AOIDensity effectivNumFixation]  = calcAOIFixDensityDist( fixStruct, aoiCenter, maxDist )
 
 Inputs:
  fixStruct: struct returned by codeFixations
       fixStruct.fixDurVector: vector of (fx1),  for duration of fications
       fixStruct.fixPosVector: in format [ x x x ... x; 
                                                          y y y ... y]
  aoiCenter: coordinates of AOI in image scale, returned by 'returnAOICenters.m'
  maxDist: maximum distance to a nearest AOI, anything further
   considered not part of any AOI, returned by 'returnAOICenters.m'
 
 Outputs:
  AOIDensity: vector of number of relative time spent at particular AOI

0001 % calculate fixation density at the AOIs
0002 %
0003 % Syntax: [ AOIDensity effectivNumFixation]  = calcAOIFixDensityDist( fixStruct, aoiCenter, maxDist )
0004 %
0005 % Inputs:
0006 %  fixStruct: struct returned by codeFixations
0007 %       fixStruct.fixDurVector: vector of (fx1),  for duration of fications
0008 %       fixStruct.fixPosVector: in format [ x x x ... x;
0009 %                                                          y y y ... y]
0010 %  aoiCenter: coordinates of AOI in image scale, returned by 'returnAOICenters.m'
0011 %  maxDist: maximum distance to a nearest AOI, anything further
0012 %   considered not part of any AOI, returned by 'returnAOICenters.m'
0013 %
0014 % Outputs:
0015 %  AOIDensity: vector of number of relative time spent at particular AOI
0016 
0017 
0018 function [ AOIDensity effectivNumFixation]  = calcAOIFixDensityDist( fixStruct, aoiCenter, maxDist ) 
0019 
0020 
0021 % fixationVector P
0022 fixPosVector = fixStruct.fixPosVector;
0023 fixDurVector = fixStruct.fixDurVector;
0024 
0025 %calculate AOI fixation density
0026 numAOI = size(aoiCenter,2);
0027 numFixation = size( fixPosVector,2);
0028 AOIDensity = zeros( numAOI,1);
0029 effectivNumFixation = 0;
0030 
0031 for i1 = 1:numFixation  
0032     dist = calc2Dist( fixPosVector(:,i1), aoiCenter); % 2-norm
0033     [minDist minIdx] = min( dist);    
0034     if minDist < maxDist 
0035         effectivNumFixation = effectivNumFixation+1;
0036         AOIDensity(minIdx) = AOIDensity(minIdx) + fixDurVector(i1);
0037     end       
0038 end
0039 
0040 % normalize so the sum is 1
0041 if effectivNumFixation > 0
0042     AOIDensity = AOIDensity/sum( AOIDensity);
0043 end
0044 
0045