How can I track the interface of image?

Hi everyone. I have 75 binary frames. each frame has a size of Height=301 and width=1483. I attached you the first frame for your record. What I want is that I want to know the average height from the bottom of image to the interface where white pixel exist.let's say that I pick up 5 arbitrary points, as shown in the attached file and take an average of the height from these five points. This procedure must be repeated for all 75 frames. The idea is that we should track all white pixel in the domain from bottom to top of column. If there is white point then we store it, so that we can identify the interface of each image. any help would be appreciated.

Answer 1

[Image Analyst]

It depends. Do you want to go to the bottom of the little particles? Or just the big one. If you're interested in just the big one, use bwareafilt(binaryImage, 1) to extract just the biggest blob. If you want to get a smooth envelope that sort of goes between the large and small blobs, use activecontour (demo attached). If you want to just go to the bottom of any blob, then just process columns one at a time

[rows, columns] = size(binaryImage);
bottomRows = zeros(1, columns);
for col = 1 : columns
    thisColumn = binaryImage(:, col);
    botCol = find(thisColumn, 1, 'last');
    if ~isempty(botCol)
        % There is at least one white pixel in this column.
        bottomRows(col) = botCol;
    end
end
% Now find mean
theSum = sum(bottomRows);
numCols = sum(bottomRows ~= 0);
meanBottomRow = theSum / numCols;

[Parham Babakhani Dehkordi]

to answer your question, I must emphasize that I am interested in the bottom of large bubbles not the small one.then, in each column, I need to know the height from bottom of image to the interface where big bubble exists. so, in this case we have a curve (if you look at the attached photo).

[Parham Babakhani Dehkordi]

I think you only specify the bottom column in which zero value exists not the distance from these interface to the bottom of images.

[Image Analyst]

Get that largest blob like this:

binaryImage = bwareafilt(binaryImage, 1);

Put that before the code I gave you to extract only the largest bubble.

To get the distance from the bottom edge of the image, subtract the mean bottom row from the number of rows

meanDistance = rows - meanBottomRow;

[Parham Babakhani Dehkordi]

well-done, helped a lot

[Parham Babakhani Dehkordi]

I have another question.Imagine that I have a video. frequency is 50frames/s. from this video (named as A), we can extract 3128 frames. how can I extract these frames with the name 00001image-00002image....00010image...00100image...01000image and so on up to the last image which is 03128image . I want this photos in this subsequent way.