Get an image export with plot hold on

Hi, I was wondering if anyone would know how to export an image that has had a hold on it and a Plot. I'll explain.

I have an image where I detect the contour and what I want to save is the original image where the points that are blue contours overlapping the original image are shown.

clear all; clc; close all
I = rgb2gray(imread('tumor_091R.tif'));
BW = edge(I,'Canny',100/255);
[r,c] = find(BW == 1);

figure
imshow(I)
hold on
plot(c,r,'.')

exportgraphics(gcf,'11.tif')

When I'm in Matlab and I zoom in on a certain area what I get is this:

But when I export it using the exportgraphics command what I get when I zoom in on the area I want to see is a spot of the type I show:

What I want to achieve is that the image I export allows me to zoom in as Matlab does, I tried the getframe option but the result was the same. Thanks in advance

Answer 1

[Ameer Hamza]

If you want to zoom on the image, than you may try to save it in a vector format, e.g., eps file format. Try this

clear all; clc; close all
I = rgb2gray(imread('tumor_091R.tif'));
BW = edge(I,'Canny',100/255);
[r,c] = find(BW == 1);
fig = figure;
imshow(I)
hold on
plot(c,r,'.')
fig.Renderer = 'painters'; % render the points as vector
exportgraphics(gcf,'11.eps')

Alternatively, you can also use this excellent FEX package to save in high-res raster format: https://www.mathworks.com/matlabcentral/fileexchange/23629-export_fig

clear all; clc; close all
I = rgb2gray(imread('tumor_091R.tif'));
BW = edge(I,'Canny',100/255);
[r,c] = find(BW == 1);
fig = figure;
imshow(I)
hold on
plot(c,r,'.')
export_fig(gcf,'11.tif', '-r500'); % 500 is PPI of the image

[Alejandro Fernández]

Hi, it worked, the only thing the dots still look huge when I zoom in, but I guess the only way to fix it is to change the markersize to a smaller size or can you think of some other way?

So the result is not exactly what I would have liked to get...

[Ameer Hamza]

Does this also happen in the eps format? This seems like a limitation of MATLAB's rasterization algorithm, and decreasing marker size will not be of much help.

[Alejandro Fernández]

Yes, it's the same if I use .eps ...

[Ameer Hamza]

Can you try it by increasing the resolution in export_fig

export_fig(gcf,'11.tif', '-r1000');

If this too does not work, then it probably not possible to get a better quality in the exported file.

[Alejandro Fernández]

It still doesn't work but that's okay, I still thank you very much for all your help.

[Ameer Hamza]

If possible, you may try to install R2018b and try to export eps in that version. I have already noticed that saving a complex graphic in vector format have greatly degraded after that version. That is why I keep an installation of R2018b just for this purpose. If this is extremely important, you may give it a try, although I am not sure that it will still work. It is just a guess.

[Alejandro Fernández]

I'm sorry it took me a while to answer you, I tried to do it with the 2018b version but nothing, I'm afraid the result is still the same.

Thank you very much for everything anyway.