MATLAB: PIV plot problems – function not well invoked

piv

Hi! So, I'm trying to use a particle image velocimetry (PIV) script and I am kind of stuck with a quiver function.
This is the main code for the PIV, where several functions are invoked (m. files for these functions can be found at http://folk.uio.no/jks/matpiv/Download/files.html ):
close all;clear all;clc;
addpath(fullfile(cd,'piv & other functions'));
global max_sp_dsply
USER INPUT pixel size in Microns, Time in sec
win_piv=64;
pxl_sz=.178;
tm_int=2;
max_sp_dsply=.5;
% ROI 1 Input the corordinates to define rectangle       
r1_xmin = 176
r1_xmax = 280
r1_ymin = 30
r1_ymax = 185
% ROI 2

r2_xmin = 78
r2_xmax = 133
r2_ymin = 30
r2_ymax = 181
[filename, pathname] = uigetfile({'*.*'}, 'Input your stack (.tif)');
avi_filename2=filename;
img_info=imfinfo(fullfile(pathname,filename));
Num_file=length(img_info)
res_folder=fullfile(pathname,[filename '_Results']);
mkdir(res_folder);
mkdir(res_folder,'PIV velocity text');
mkdir(res_folder,'PIV r1 velocity text');
mkdir(res_folder,'PIV r2 velocity text');
mkdir(res_folder,'PIV quiver image');
for ifile=1:Num_file-1
          f1=imread(fullfile(pathname,filename),ifile);
          f2=imread(fullfile(pathname,filename),ifile+1);
          [x,y,u1,v1]= matpiv(f1,f2,win_piv,tm_int,0.5,'single'); % matpiv(image1,image2,size of window,time_interval, overlap, looping for window)
          u=pxl_sz*u1;   % x, y, u1, v1 => matrix
          v=pxl_sz*v1;   
    % ~~~~~~~~~~~~~~~~~~~~~~       Filter and interpolate      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 
          v(isnan(v))=0;  u(isnan(u))=0;      % Make NaN values = 0        
          [lu,lv]=localfilt(x,y,u,v,2,'median');
          [fu,fv]=naninterp(lu,lv,'weighted');
          u=fu;  
          v=fv;   % fu, fv => matrix            
    % ~~~~~~~~~~~~~~~~~~~~~~~~~~~~     Get x,y,u,v vector    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 
          xx=x(:);  yy=y(:);  % xx, yy, uu, vv => vector
          uu=u(:);  vv=v(:); 
          zz=sqrt((uu.^2)+(vv.^2));
          temp_mat=[xx,yy,uu,vv];
          csvwrite(fullfile(res_folder,'PIV velocity text',[avi_filename2 '_' num2str(ifile),'.txt']), temp_mat);    
     % ~~~~~~~~~~~~~~~~~~~~~~~~~~~~     Get x,y,u,v of roi  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 
          % ROI 1
          idx_r1 = find(xx<=r1_xmax & xx>=r1_xmin & yy<=r1_ymax & yy>=r1_ymin);
          xx_r1 = xx(idx_r1);
          yy_r1 = yy(idx_r1);
          uu_r1 = uu(idx_r1);
          vv_r1 = vv(idx_r1);
          csvwrite(fullfile(res_folder,'PIV r1 velocity text',[avi_filename2 '_' num2str(ifile),'.txt']), [xx_r1,yy_r1,uu_r1,vv_r1]); 
          abs_avg_uu_r1(ifile) = abs(mean(uu_r1));
          abs_avg_vv_r1(ifile) = abs(mean(vv_r1));
          % ROI 2
          idx_r2 = find(xx<=r2_xmax & xx>=r2_xmin & yy<=r2_ymax & yy>=r2_ymin);
          xx_r2 = xx(idx_r2);
          yy_r2 = yy(idx_r2);
          uu_r2 = uu(idx_r2);
          vv_r2 = vv(idx_r2);
          csvwrite(fullfile(res_folder,'PIV r2 velocity text',[avi_filename2 '_' num2str(ifile),'.txt']), [xx_r2,yy_r2,uu_r2,vv_r2]); 
          abs_avg_uu_r2(ifile) = abs(mean(uu_r2));
          abs_avg_vv_r2(ifile) = abs(mean(vv_r2));
     % ~~~~~~~~~~~~~~~~~~~~~~~~~~~        Quiver plot        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 
          xx(~vv)=0;  yy(~uu)=0;    % Removing null zeros during ploting   
          scaled_quiver2(xx,yy,uu,vv,f1);
          set(gcf, 'Position', get(0,'Screensize'));
          print('-dtiffnocompression','-r300',fullfile(res_folder,'PIV quiver image',[num2str(ifile),'.tif'])); 
          close all;
end
% ~~~~~~~~~~~~~~~~~~~~~~~~~~~        Scale bar        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 
cmap = jet(36); % 1:35 level , define a color map with 35 levels
rgb_cmap = reshape(flipud(cmap),[length(cmap) 1 3]);
figure;
imagesc(rgb_cmap);
x_y_w_h1=get(gcf,'Position');
x_y_w_h2=get(gca,'Position');
x_y_w_h1(3)=150;
x_y_w_h2(3)=0.2;
x_y_w_h2(1)=x_y_w_h2(1)+0.25;
set(gcf,'Position',x_y_w_h1); 
set(gca,'Position',x_y_w_h2); 
set(gca,'XTickLabel','');
set(gca,'TickLength', [0 0]);
set(gca,'YTick',1:36);
set(gca,'YTickLabel',{num2str(max_sp_dsply),'','','','','','','','','','','','','','','','','','','','','','','','','','','','','','','','','','','0'}); 
clrbar=getframe(gcf);
imwrite(clrbar.cdata,fullfile(res_folder,'PIV quiver image','scale bar.tif'));
xlswrite(fullfile(res_folder,'PIV quiver image','Absolute average u & v for r1 & r2.xlsx'),{'Frame','abs_avg_uu_r1','abs_avg_vv_r1','abs_avg_uu_r2','abs_avg_vv_r2'},1,'A1');
xlswrite(fullfile(res_folder,'PIV quiver image','Absolute average u & v for r1 & r2.xlsx'),[[1:Num_file-1]' abs_avg_uu_r1' abs_avg_vv_r1' abs_avg_uu_r2' abs_avg_vv_r2'],1,'A2');
close all;
So, my problem is at the Quiver plot step, where an error is displayed:
Undefined function or variable 'scaled_quiver2'.
Error in main_PIV (line 129)
        scaled_quiver2(xx,yy,uu,vv,f1);
So probably the function on the respective m. file has a different name. I've downloaded all the m.files to the MATLAB folder, so I presume there's no function missing. It should be just a matter of different names, but I'm not sure. I think it refers to the vekplot2 function http://folk.uio.no/jks/matpiv/Download/Files/vekplot2.m, but not sure about this. So please, if anyone could give me some help here, I would really appreciate it!
Thanks a lot!
Joana

Best Answer

is unlikely to refer to vekplot2 .
The package you refer to does not appear to define scaled_quiver2 . Nothing else public on the Internet does either.
I speculate that it is something like
function scaled_quiver2(x, y, u, v, img)
  image(img);
  hold on;
  S = 0;
  quiver(x, u, u, v, S);
  hold off;
but possibly with S = 1
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