MATLAB: Resize an image by deleting columns

horizontal compressionImage Processing Toolboxresize an image by deleting columns

 How are you everyone!
Today I have a binary image and I want to resize it by deleting columns which have zero values, for this purpose I can use this command
a(:,any(a))=[];
the problem with this command is that I want to leave just one zero-value column to keep regions separated. Could you help me to solve this problem
Thank you!

Best Answer

This will do it:
% Create sample image data
m = 255*[0 1 0 1 0 0 0 0 1 1 0 0 0 1 1 0 0 0;
0 1 1 1 0 0 0 0 1 1 0 0 0 1 0 0 0 0;
0 1 1 1 0 0 0 0 1 1 0 0 0 1 1 0 0 0]
% Find all zero columns
totallyBlankColumns = ~any(m, 1)
measurements = regionprops(logical(totallyBlankColumns), 'PixelIdxList');
% Make an array to keep track of which columns we will want to remove.
columnsToDelete = false(1, length(totallyBlankColumns));
% For each region, if it's more than 3 columns, keep track
% of which columns to delete (the second and subsequent columns in that run).
for region = 1 : length(measurements)
  % Get indexes of this run of zeros.
    theseIndexes = measurements(region).PixelIdxList
  % If there are more than 1 of them, delete the second onwards in this run.
  if length(theseIndexes) >= 2
    columnsToDelete(theseIndexes(2:end)) = true;
  end
end
% Get a new m by removing those columns
mCompressed = m(:, ~columnsToDelete)
  
Shows in command window:
m =
     0   255     0   255     0     0     0     0   255   255     0     0     0   255   255     0     0     0
     0   255   255   255     0     0     0     0   255   255     0     0     0   255     0     0     0     0
     0   255   255   255     0     0     0     0   255   255     0     0     0   255   255     0     0     0
totallyBlankColumns =
     1     0     0     0     1     1     1     1     0     0     1     1     1     0     0     1     1     1
theseIndexes =
     1
theseIndexes =
     5
     6
     7
     8
theseIndexes =
    11
    12
    13
theseIndexes =
    16
    17
    18
mCompressed =
     0   255     0   255     0   255   255     0   255   255     0
     0   255   255   255     0   255   255     0   255     0     0
     0   255   255   255     0   255   255     0   255   255     0
And you can see the array is compressed horizontally so that there is only a single column of zeros separating the columns that have something in them. If it works, please accept the answer.
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