Bubble shape detection and creating of the mask

Dear Matlab community,

I am totally new in the image processing. Nevertheless, I need to define the bubble on image, create mask and apply the mask to the original image. If someone can help me or give any useful advice, I will be really thankful.

Issue: I have a set of images (2000 for example) at which the bubble is growing and I need to define the bubble shape at each image and apply it for the its original.

I guess that it may be really easy (or not), I just have no any idea. I've already read a number of articles which dedicated the processing issues, but still have not solved problem.

So, I attached original image and three images after some manipulations. It doesn't matter which image you can offer to process. Thanks in advance!

Original:

Processed_1:

Processed_2:

[Image Analyst]

Can you attach images that show the smallest bubble that you will encounter, and the largest bubble that you will encounter. Also state whether the bubble will always be centered at the same location, atop that tube or stalk. What about the thing under the bubble - is that part of the bubble or not? Can we use a mask to exclude part of the image right off the bat, like the bottom 50 lines or the right-most 200 columns or whatever? Can you change the lighting or optics to get a better image to start with? Like use polarization, or reduce the amount of "debris" in the liquid, or make the bubble edge brighter. Like maybe you can put Tinopal into the fluid and illuminate with UV light so the bubble is darker than the surrounding fluid.

[Aleksandr Bashkatov]

Dear Image Analyst,

1. I attached the images for smallest bubble (but it also could be bigger) and for the biggest one.

2. The bubble are produced by chemical reactions (water electrolysis). During the time the bubble is at the same position. The part which is under the bubble could be removed (it is not part of the bubble). My purpose just create mask and then apply for original image - part of the image could be excluded from the processing.

3. I am sorry that I forgot to say that I use PIV method for flow visualisation. For the reason this "debris" are fluorescent particles. It means that I cannot change the solution (due to chemical reaction) and cannot remove the particles. To observe the bubble I used the microscope with magnification 6.3 and I guess the quality which I have now is the best I can have.

I will be glad for any idea (hopefully useful), thanks in advance!

[Image Analyst]

It could be that manually deciding where the circle is with imellipse() will actually be quicker, and possibly more robust and accurate, that trying to do it automatically, especially if you consider the time it might take to write such a robust and accurate program. I mean 2000 images at 10 seconds each is about 5 and a half hours. Sure it's tedious, but I bet you'd spend more than 5 hours developing this algorithm. Would you consider using imellipse()?

[Aleksandr Bashkatov]

Thanks, I will try use imellipse. Actually, may be it would be better.

Thanks again!

Best regards, Aleksandr

[Aleksandr Bashkatov]

Dear Image Analyst,

I am sorry for my stupid question again=) Now, I almost solved my problem by means of imellipse.

However, now I have one more question. Hopefully that I didn't waste your time.

My code which I used now:

     srcFiles = dir('C:\path\*.tif');  
          OutVideoDir = 'C:\path\Out';
          for i = 1 : length(srcFiles)
              filename = strcat('C:\path\',srcFiles(i).name);
              I = imread(filename);
              figure;
              imshow(I,[]);
              h = imellipse(gca, [326 455 236 236]);
              addNewPositionCallback(h,@(p) title(mat2str(p,3)));
              fcn = makeConstrainToRectFcn('imellipse',get(gca,'XLim'),get(gca,'YLim'));
              setPositionConstraintFcn(h,fcn);

              k = imellipse(gca, [326 1255 236 236]);
              l = imellipse(gca, [324 2060 236 236]);
              m = imellipse(gca, [324 2860 236 236]);

              %accepted_pos = wait(h)
              BW1 = createMask(h);
              BW2 = createMask(k);
              BW3 = createMask(l);
              BW4 = createMask(m);
              BW = BW1+BW2+BW3+BW4;
              BW = 1-BW;
             % subplot(1,2,1), imshow(BW), title('Mask');
              maskedImage=I .* cast(BW, class(I));
              %subplot(1,2,2), imshow(maskedImage,[]), title('Masked image');

               baseFileName = sprintf('%d.tif', i);
               fullFileName = fullfile(OutVideoDir, baseFileName); 
               imwrite(maskedImage, fullFileName);
              close
          end

So, I need to process a number of images (the ellipse will growth - I will add function of the coordinate changing later). When I run the process - it works. But each time, the window with the image is opened, due to the "imshow(I,[]);". And it is really interfere the work on the PC. These windows with the image bar constantly "flickers". Can you maybe give an advice how to hide this process? Thanks in advance!

Best regards, Aleksandr

Answer 1

[Image Analyst]

Get rid of this line of code:

figure;

[Aleksandr Bashkatov]

Many thanks. It's solved in so easy way=) I need to study basic things..