Composite of multiple small images over a larger background image

Hello everyone,

Allow me to concisely set the scene for my question. I am currently running a bunch of simulations that result in ternary composition diagrams using MATLAB. For the sake of comprehensiveness of the dataset I am making composites of images overlayed over a background. To be exact, I am using one background for every figure and am than inserting 66 smaller figures on certain locations in the figure.

For an example you can check the attached figure. As you can see, the smaller images require to be at exact spots in the larger image.

The figures are all generated in MATLAB and then saved as .png using the export_fig function.

Currently I am doing this operation in Powerpoint but it takes a very long time to complete one figure and it is also very repetitive. I would thus like to know if it is possible do automate this process using matlab, i.e. overlaying multiple figures at specified locations over a background figure...

Regards

Dries

[KSSV]

Yes this can be done...You need to initialize a big matrix...and fill these small image pixel values and the specified locations and at the end use imshow to display the image.

[Dries Weytjens]

How would I initialise this matrix? By using imread for the background image? And how would I specify the locations of the figures that I need? I have included the background image and one of the smaller images in the attachments. I don't want to be too demanding but could you give a concise example on how I should put this small image over the larger one, any location is fine. Thanks!

[KSSV]

How you got the image terncomp? How you have drawn it?

[Dries Weytjens]

The terncomp image is downloaded from the internet but it can also be generated using a matlab script if this would be better, an example generated in Matlab is in the attachment.

Answer 1

[KSSV]

If you have coordinates of the triangles in hand, it can be automated with ease....Check the below code...when figure is prompted click twice to cover a triangle as to get a bounding box. Click the points as to make a square which covers whole triangle. That clicked area will be filled by the small image. You can further take care of transparency on reading the documentation of how to show .png files.

[I,map] = imread('big.png') ;
Is = imread('small.png') ;

figure
image(I)
hold on
for i = 1:10
    [x,y] = ginput(2) ;
    image([x(1) x(2)] ,[y(1) y(2)],Is) ;
end

If the coordinates are in hand, instead of clicking the point limits can be incorporated to automate.

[Dries Weytjens]

Thank you for this effort. I am checking on how I can get the background of the smaller figures to disappear but I am not finding concrete answers to this. What would you do for this? The figures were made using export_fig and the background have been deleted in this program.

[KSSV]

Use .jpg instead of .png.

Answer 2

[Image Analyst]

Here's the official Mathworks instructions for sending pictures from MATLAB to Powerpoint: https://www.mathworks.com/matlabcentral/answers/103175-how-can-i-create-slides-in-ms-powerpoint-2007-using-matlab-7-13-r2011b. It uses ActiveX. With ActiveX you can do virtually anything from MATLAB that you could do in Powerpoint itself. For example, specifying where on the slide the image should be put.

If you still want to go with the pasting small images onto a larger image, like KSSV suggested, and then inserting only one picture within Powerpoint, then see my attached copy and paste demo.

[Dries Weytjens]

Thank you for your input. Unfortunately ActiveX will not be an option since I am using a Mac OS.