overlay plot on imgage

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Don 2017-10-2

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评论： Cedric 2017-10-7

I have images of artwork and plots of data from an eye tracker. I want to overlay the data plots on the images. A complication: artwork images come in different sizes. I think the subplot function will do some of this be I don't know how. Any help is greatly appreciated

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Answer 1

Cedric 2017-10-2

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https://ww2.mathworks.cn/matlabcentral/answers/359379-overlay-plot-on-imgage#answer_284012

编辑：Cedric 2017-10-2

在 MATLAB Online 中打开

hold on

for overlays, for example:

 imshow( myImage ) ;
 hold on ;
 plot( x, y, 'rx' ) ;

and you will see the plot over the image. You can have more control by creating axes by yourself, but it is more complicated. For this, if you really have the time to learn, look at my answer here.

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Don 2017-10-5

编辑：Cedric 2017-10-5

在 MATLAB Online 中打开

OK.. Here's what I have so far:

Figure(2)

disp (' get image that goes with the data file');

These are all images of different sizes. Are pictures of famous paintings

 [filename, filepath] = uigetfile('*.jpg', 'Select ejpg  file');
 pict = cat(2,filepath,filename);
 [X,map] = imread(pict);
 figure('position', [1, 10,10,10]);

I doubt this statement is necessary or useful. I think I want to fix the image to standard size

 hold on;
 figure(3);
 positiveXaxisMask = xaxis >0 & xaxis < 1 & yaxis >0 & yaxis <1;

this stuff plots eye fixations from a data set

 plot(xaxis(positiveXaxisMask),  yaxis(positiveXaxisMask),'color','r','marker','o','LineStyle','--');
   axis([0 1 0 1]);
 x0 = 300;   % seet size of plot
 y0 = 75;
 width = 675;
 height = 675;
 set(gcf,'units','points','position',[x0,y0,width,height])
 % axis([0,1,0,1]);
 xlabel(' Left<---                                   ---> Right');
 ylabel('Bottom <--                                   -->  Top') 
 TitleText=cat(2,'XY Coordinates of Fixation  ',name);
 title (TitleText);
 TrackerData = cat(2,name,'.png');

eventually save the result

 TrackerData = cat(2, PathName,TrackerData);
 saveas(gcf,TrackerData);     % save plot to subj direcory

Many thanks for any help you can give Don

Cedric 2017-10-5

编辑：Cedric 2017-10-5

在 MATLAB Online 中打开

MonaLisa.jpg

You have to try little bit by little bit. First with

 figure('position', [1, 10,10,10]);                                            
 hold on;
 figure(3);

you create a tiny figure in the lower-left corner of your screen, then you tell MATALB not to overwrite its content but to overlay whatever will be plotted next, then you create a new figure. What is the purpose of the first?

I'd say, forget about all the code for user management, scaling, etc, at first and work with a static image, e.g. the MonaLisa attached.

So first, are we able to create a empty large figure?

figure() ;

well, it's a new empty figure but not that large. Can we set its position/size relative (normalized) to the screen?

set( gcf, 'Units', 'normalize', 'Position', [0.1,0.1,0.8,0.7] ) ;

where the vector of positions is [x,y,w,h] given as a fraction of the screen size (so x=10%, y=10%, w=80%, h=70%).

Great, first part is working and it is two lines long. Then, are we able to plot something? Let's try a sine wave, just for the test:

 x = 1 : size(img, 2) ;                   % 1 pixel to the width of the image.
 y = size( img, 1 ) * (sin(x/50)+1) / 2 ; % Scale a sine to the height of the image.

If we plot it in the current figure, it will clear the previous content first, unless we tell MATLAB that it must "hold" the previous content and overlay the new:

 hold( 'on' ) ;
 plot( x, y, 'b' ) ;

That seems to work too:

(sorry for the sacrilege by the way ;))

So now we know how to plot, overlay curves, and we can "complexify" the code a little by working on the curves that you need to plot.

I let you check if this works for you and try the next steps, always making small steps.

Don 2017-10-6

编辑：Cedric 2017-10-6

在 MATLAB Online 中打开

The code you sent works GREAT for plotting sine wave over any of my pictures

figure(3);    
set( gcf, 'Units', 'normalize', 'Position', [0.1,0.1,0.8,0.7] ) ;
img = imread(imgLocator) ;
imshow(img)  ;  
hold( 'on' ) ;
x = 1 : size(img, 2) ;                   % Pixel 1 to the width of the image.
y = size(img, 1) * (sin(x/50)+1) / 2 ;   % Scale a sine to the height of the image.
plot( x, y, 'r', 'LineWidth', 3 ) ;

BUT, getting this data to plot over the picture is non trivial for me. This code gets the plot shown below

figure(2);
positiveXaxisMask = xaxis >0 & xaxis < 1 & yaxis >0 & yaxis <1;
plot(xaxis(positiveXaxisMask), yaxis(positiveXaxisMask),'color','r','marker','o','LineStyle','--');
x0 = 300;   % set size of plot
    y0 = 75;
    width = 675;
    height = 675;
    set(gcf,'units','points','position',[x0,y0,width,height])
    xlabel(' Left<---                                   ---> Right'); 
    ylabel('Bottom <--                                   -->  Top')  
    TitleText=cat(2,'XY Coordinates of Fixation  ',name);
title (TitleText);