Reading the image sequency

Hello,

In a folder, I have series of images and name of the first image is "Field on_1ms_4_8V_60sec-02-Deskew_t001z001c1-2". The file name is changing "t001z001c1-2" from here. Number after t and number after z and sometimes number after c. How can I read the sequence of images using a loop ?

[Walter Roberson]

Do you just need to process all of them in some order, or do you need a specific order? For example, would you proceed to process t002z001c1-2 then t003z001c1-2 ... then back to t001z002c1-2 then t002z002c1-2 and so on?

[Bipul Biswas]

Sorry, I was not enough clear about it.

First I want to calculate for a fixed z value with variable t and then the next value of z and it's corresponding ts, and so on. Also I want to save the images accordingly.

[Image Analyst]

Were you not able to use the FAQ I pointed you to below in my Answer? If you have a list of z's and t's you can use sprintf() like it shows in the FAQ to build the filenames in a loop.

[Walter Roberson]

To confirm, you would process in the order t001z001c1-2 then t001z002c1-2 then t001z003c1-2 and so on, then t002z001c1-2 t002z002c1-2 and so on ?

[Bipul Biswas]

Thanks.. It works.

Answer 1

[Image Analyst]

See the FAQ: https://matlab.fandom.com/wiki/FAQ#How_can_I_process_a_sequence_of_files?

[Bipul Biswas]

Thanks.

Answer 2

[Walter Roberson]

%sample name "Field on_1ms_4_8V_60sec-02-Deskew_t001z001c1-2"

projectdir = 'name/of/directory/data/files/are/in';
basefilename = 'Field*';
qualifiedname = fullfile(projectdir, basefilename);

dinfo = dir(qualifiedname);
filenames = fullfile({dinfo.folder}, {dinfo.name});
numfiles = length(filenames);
if numfiles == 0
    error('No files found for "%s"', qualifiedname);
end

%extract the last component of the file names
[~, basenames] = fileparts(filenames);
lastparts = regexp(basenames, '(?<=.*_)[^_]+$', 'match', 'once');

%now for each one, extract the groups of digits, still as characters
numpart_strings = regexp(lastpart, '\d+', 'match');  %not 'once' !

%convert them to numbers
numpart_numerics = cellfun(@str2double, numpart_strings, 'uniform', 0);

%do not assume that we have the same number of groups for each.
%for example there might perhaps be t001z001c2 without a -* component
%so find the longest group and pad the others to that size.
longest_group = max(cellfun(@length, numpart_numerics));
numpart_numerics = cellfun(@(V) [V, zeros(1, longest_group - numel(V))], 'uniform', 0);
%having done that, create a numeric array in which each row is the groups
numpart_numerics = vertcat(numpart_numerics{:});

%the rule seems to be that each further component right is a subgroup of
%the one further left
[~, order_of_files] = sortrows(numpart_numerics);

%and reorder the filenames to match the wanted numeric order
filenames = filenames(order_of_files);

imgs = cell(numfiles, 1);
failed_files = false(numfiles,1);
%now we can loop over the files
for K = 1 : numfiles
    thisfile = filenames{K};
    try
        img = imread(thisfile);
        imgs{K} = img;
    catch ME
        fprintf(2, 'could not read image file: "%s"\n', thisfile);
        failed_files(K) = true;
    end
end

%all of the files are now read into "imgs". 
%any failures have empty cell and failed_files is true at that location

%now what?

[Bipul Biswas]

Thanks