Merge branch 'master' of git.rwth-aachen.de:ita/toolbox

applications/Binaural-HRTF/HRTF_class/@itaHRTF/interp.m

@@ -50,7 +50,8 @@ function cThis = interp(this,varargin)
 
 sArgs           = struct('order',50,'eps',1e-5,'shiftToEar',false,'shiftAxis','y','shiftOffset',[-0.0725 0.0725]);
 sArgs           = ita_parse_arguments(sArgs,varargin,2);
-if ~isa(varargin{1},'itaCoordinates'),error('itaHRTF:interp', ' An itaCoordinate object is needed!')
+if isempty(varargin) || ~isa(varargin{1},'itaCoordinates')
+    error('itaHRTF:interp', ' An itaCoordinate object is needed!')
 end
 field_in        = varargin{1};
 

applications/Binaural-HRTF/HRTF_class/@itaHRTF/itaHRTF.m

@@ -117,6 +117,7 @@ classdef  itaHRTF < itaAudio
     methods % Special functions that implement operations that are usually performed only on instances of the class
         %% Input
         function this = itaHRTF(varargin)
+            iniAudio = [];
             % initialize itaHRTF with itaAudio properties (only for nargin == 1)
             if nargin > 1 || (nargin == 1 && (ischar(varargin{1}) || isa(varargin{1},'itaAudio')))
                 iniAudio = [];
@@ -1017,7 +1018,7 @@ classdef  itaHRTF < itaAudio
                 end
             end
             
-            % function this = interp(varargin)
+            this = interp(varargin);
             %
             % Function to calculate HRTFs for arbitrary field points using a N-th order
             % spherical harmonics (SH) interpolation / range extrapolation, as described in [1],
@@ -1055,7 +1056,8 @@ classdef  itaHRTF < itaAudio
             % Version: 2016-02-05
             
             
-            
+            this = reduce_spatial(this,coords,varargin);
+            % Function to spatially reduce the HRTF. 
             
             function this = smooth_linphase(this,varargin)
                 % function this = smooth_linphase(varargin)

applications/Binaural-HRTF/HRTF_class/@itaHRTF/reduce_spatial.m

+function [ cThis ] = reduce_spatial( this, newCoordinates, varargin )
+%
+% This function is used to reduce the spatial sampling from the current
+% directions. This is done with a findnearest search. For a reduction to
+% interpolated values use interp
+%
+% INPUT:
+%
+%
+% OUTPUT:
+%
+%
+%
+% Author:  Jan-Gerrit Richter <jri@akustik.rwth-aachen.de>
+% Version: 2017-11-23
+
+oldCoords = this.getEar('L').channelCoordinates;
+
+% if the desired sampling has more points, its probably unfeasable with
+% findnearest search. Abort
+if oldCoords.nPoints < newCoordinates.nPoints
+    error('There are more points in the wanted sampling than are available. You probably want the interp function');
+end
+
+% the new coords should have the same radius as the old ones to reduce
+% errors
+newCoordinates.r = mean(oldCoords.r);
+
+
+oldCoords = oldCoords.build_search_database;
+
+newIndex = oldCoords.findnearest(newCoordinates);
+
+% calculate all distances from the wanted points to the found points
+pointDistances = getVectorLength(newCoordinates,oldCoords.n(newIndex));
+
+% calculate the distance between two neighboring points of the new sampling
+newSamplingDistance = getVectorLength(newCoordinates.n(1),newCoordinates.n(2));
+
+% the maximum of the found points should always be smaller
+if max(pointDistances) > newSamplingDistance
+   error('The found points are further apart than the sampling allows. Something is wrong') 
+end
+
+
+cThis = this.direction(newIndex);
+
+end
+
+
+function length = getVectorLength(pointsA, pointsB)
+    
+    pointsA.r = pointsB.r;
+    vector = pointsA - pointsB;
+    length = sqrt(vector.x.^2 + vector.y.^2 + vector.z.^2);
+
+end
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