Read run-length encoding data from a table

Hi,

I have the attached table where the second column (EncodedPixels) contains the run-length encoding of bounding box masks.

I wonder how to transform each row in the column EncodedPixels into double for subsequent manipulation.

Thanks,

Jacopo

Answer 1

[dpb]

Not sure what the next step(s) are, but to convert each row use something like

data=reshape(str2double(split(tT.EncodedPixels(i)).'),2,[]).';

where i=1:height(test_table)

You can probably avoid the above step by reading the data in in proper format as numeric from the beginning, though; I presume these came from some other input file? Show us the format for it and we can probably read directly into numeric array.

[Jacopo Biasetti]

Thanks for your reply.

Here is the original file, it comes in csv format.

Answer 2

[Jan]

This is one of the files I would not import with readtable, but manually:

[fid, msg] = fopen(FileName, 'r');
assert(fid > 0, 'Cannot read file: %s', msg);

k = 0;
Header = fgetl(fid);
while ~feof(fid)
    S = fgetl(fid);
    if ~isempty(S)
        k = k + 1;
        [File, Value] = strtok(S, ',')
        Data(k).File  = File;
        Num           = sscanf(Value(2:end), '%g');
        
        % Decode run-length encoded values:
        Data(k).Value = repelem(Num(1:2:end), Num(2:2:end));
        % Or maybe:
        % ??? Data(k).Value = repelem(Num(2:2:end), Num(1:2:end));
    end
end
fclose(fid);