Home > vbmeg > functions > common > coordinate > vb_find_nearest_point.m

vb_find_nearest_point

PURPOSE ^

Find nearest points from set of vertex points

SYNOPSIS ^

function [Indx ,ddmin] = vb_find_nearest_point(Vold,Vnew,Rmax,Nstep,Mode,Disp)

DESCRIPTION ^

 Find nearest points from set of vertex points
  [Indx ,ddmin] = vb_find_nearest_point(Vold,Vnew,Rmax)
  [Indx ,ddmin] = vb_find_nearest_point(Vold,Vnew,Rmax,Nstep,Mode,Disp)
 --- Input
 Vold  : Old vertex point (Nold x 3)
 Vnew  : New vertex point (Nnew x 3)
 Rmax  : First, nearest point is searched from slice with Rmax-width
         For points with distance >= Rmax, 
         nearest point is searched from all points in 'Vold'
 --- Optional input
 Nstep : Number of steps to divide Z-axis (default = 100)
 Mode  = 0, second search step is omitted
         1, find nearest point from all points in 'Vold' (default)
 Disp  = 0 : No display output (default)
         1 : waitbar display
         2 : text message for search process
 --- Output
 Indx  : Old vertex index nearest to new vertex (Nnew x 1)
 ddmin : Distance to nearest point  (Nnew x 1)

  M. Sato  2005-12-22
  M. Sato  2006-2-3
  M. Sato  2006-3-1
 2011-06-20 taku-y
  [minor] Progress message was added. 

 Copyright (C) 2011, ATR All Rights Reserved.
 License : New BSD License(see VBMEG_LICENSE.txt)

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

0001 function    [Indx ,ddmin] = vb_find_nearest_point(Vold,Vnew,Rmax,Nstep,Mode,Disp)
0002 % Find nearest points from set of vertex points
0003 %  [Indx ,ddmin] = vb_find_nearest_point(Vold,Vnew,Rmax)
0004 %  [Indx ,ddmin] = vb_find_nearest_point(Vold,Vnew,Rmax,Nstep,Mode,Disp)
0005 % --- Input
0006 % Vold  : Old vertex point (Nold x 3)
0007 % Vnew  : New vertex point (Nnew x 3)
0008 % Rmax  : First, nearest point is searched from slice with Rmax-width
0009 %         For points with distance >= Rmax,
0010 %         nearest point is searched from all points in 'Vold'
0011 % --- Optional input
0012 % Nstep : Number of steps to divide Z-axis (default = 100)
0013 % Mode  = 0, second search step is omitted
0014 %         1, find nearest point from all points in 'Vold' (default)
0015 % Disp  = 0 : No display output (default)
0016 %         1 : waitbar display
0017 %         2 : text message for search process
0018 % --- Output
0019 % Indx  : Old vertex index nearest to new vertex (Nnew x 1)
0020 % ddmin : Distance to nearest point  (Nnew x 1)
0021 %
0022 %  M. Sato  2005-12-22
0023 %  M. Sato  2006-2-3
0024 %  M. Sato  2006-3-1
0025 % 2011-06-20 taku-y
0026 %  [minor] Progress message was added.
0027 %
0028 % Copyright (C) 2011, ATR All Rights Reserved.
0029 % License : New BSD License(see VBMEG_LICENSE.txt)
0030 
0031 if ~exist('Nstep','var')|isempty(Nstep), Nstep = 100; end;
0032 if ~exist('Disp','var'), Disp = 0; end;
0033 
0034 % New model point number
0035 Npoint  = size(Vnew,1);
0036 Indx    = zeros(Npoint,1);    % Old vertex index list
0037 ddmin    = zeros(Npoint,1);    % min distance
0038 inew    = zeros(Npoint,1);
0039 
0040 Nold    = size(Vold,1);
0041 dd        = zeros(Nold,1);
0042 iold    = zeros(Nold,1);
0043 Vold2    = zeros(Nold,3);
0044 
0045 % Slice definition
0046 Zmax  = max(Vnew(:,3));
0047 Zmin  = min(Vnew(:,3));
0048 Zstep = (Zmax-Zmin)/Nstep;
0049 
0050 if Zstep == 0
0051     Zstep = 0.001;
0052     Zlist = [Zmin , Zmin + Zstep/2];
0053     Nstep = 1;
0054 else
0055     Zlist = Zmin:Zstep:Zmax;
0056     Zlist(Nstep+1) = Zmax + Zstep/2;
0057 end
0058 
0059 if ~exist('Rmax','var')|isempty(Rmax),  Rmax  = Zstep; end;
0060 
0061 if Disp == 1,
0062   prg = 0;
0063   prg_all = Nstep;
0064   h = waitbar(0,'Nearest point search');
0065   vb_disp_nonl(sprintf('%3d %% processed',ceil(100*(prg/prg_all))));
0066 end
0067 
0068 % Find nearest point from slice region
0069 % Loop for slices in z-direction
0070 for n=1:Nstep,
0071     % Find vertex points in this slice
0072     inew  = find( Vnew(:,3) >= Zlist(n) ...
0073                 & Vnew(:,3) <  Zlist(n+1) );
0074     iold  = find( Vold(:,3) >= (Zlist(n)   - Rmax) ...
0075                 & Vold(:,3) <  (Zlist(n+1) + Rmax) );
0076 
0077     Nnew  = length(inew);
0078     Nold2 = length(iold);
0079     Vold2 = Vold(iold,:);
0080     
0081     switch Disp
0082     case 1,
0083        waitbar(n/Nstep);
0084            for ii=1:15; vb_disp_nonl(sprintf('\b')); end
0085            vb_disp_nonl(sprintf('%3d %% processed',ceil(100*(prg/prg_all))));
0086            prg = prg+1;
0087     case 2,
0088        fprintf('Searching for %d vs %d points in %d-th slice \n',Nnew,Nold2,n)
0089     end
0090     
0091     if Nold2 == 0, ddmin(inew) = Rmax; continue; end;
0092 
0093     for i=1:Nnew,
0094         k      = inew(i);            % New vertex index
0095         Vnew2 = Vnew( k,:);
0096         
0097         % Distance between new and old vertex
0098         dd    = (Vold2(:,1) - Vnew2(1)).^2 ...
0099             + (Vold2(:,2) - Vnew2(2)).^2 ...
0100             + (Vold2(:,3) - Vnew2(3)).^2;
0101             
0102         % Find nearest old vertex
0103         [md,ix]  = min(dd); 
0104         Indx(k)  = iold(ix);     % Old vertex index for 'k'
0105         ddmin(k) = md;          % min distance
0106     end;
0107 
0108 end
0109 
0110 ddmin = sqrt(ddmin);
0111 
0112 if Disp == 1, 
0113   close(h);
0114   drawnow;
0115   vb_disp_nonl(sprintf('\n'));
0116 end
0117 
0118 if exist('Mode','var') & Mode == 0; return; end;
0119 
0120 % Find min distance is larger than Rmax
0121 ixmax = find( ddmin >= Rmax | Indx == 0 );
0122 Nmax  = length(ixmax);
0123 
0124 if Nmax==0, return; end;
0125 
0126 switch Disp
0127  case 1,
0128   fprintf('Searching large distance %d vs %d points\n',Nmax,Nold)
0129   h = waitbar(0,'Distant point search');
0130   prg = 0;
0131   prg_all = Nmax;
0132   vb_disp_nonl(sprintf('%3d %% processed',ceil(100*(prg/prg_all))));
0133  case 2,
0134   fprintf('Searching large distance %d vs %d points\n',Nmax,Nold)
0135 end
0136 
0137 % Find nearest point from all vertex
0138 for i=1:Nmax,
0139     k      = ixmax(i);            % New vertex index
0140     Vnew2 = Vnew( k,:);
0141     
0142     % Distance between new and old vertex
0143     dd    = (Vold(:,1) - Vnew2(1)).^2 ...
0144         + (Vold(:,2) - Vnew2(2)).^2 ...
0145         + (Vold(:,3) - Vnew2(3)).^2;
0146         
0147     % Find nearest old vertex
0148     [md,ix]  = min(dd); 
0149     Indx(k)  = ix;     % Old vertex index for 'k'
0150     ddmin(k) = md;  %  min distance
0151 
0152     if Disp == 1, 
0153       waitbar(i/Nmax);
0154       for ii=1:15; vb_disp_nonl(sprintf('\b')); end
0155       vb_disp_nonl(sprintf('%3d %% processed',ceil(100*(prg/prg_all))));
0156       prg = prg+1;
0157     end
0158 end
0159 
0160 ddmin(ixmax) = sqrt(ddmin(ixmax));
0161 
0162 if Disp == 1, 
0163   close(h);
0164   drawnow;
0165   vb_disp_nonl(sprintf('\n'));
0166 end
0167 
0168 clear inew dd iold Vold2
0169 
0170 return;
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