i want to save names of the images(frame_0000, frame_0001, frame_0003........) in a text file by reading them from a folder.

i want to save names of the images(frame_0000, frame_0001, frame_0003........) in a text file by reading them from a folder. somehow i am getting errors while writing the code. As i am new to MatLab please help me. Waiting for your response.

[Geoff Hayes]

sidra - somehow i am getting errors while writing the code. What is the code? What are the errors?

Answer 1

[Stephen23]

D = 'directory where images are';
S = dir(fullfile(D,'*.jpg'));
% Save filenames:
[fid,msg] = fopen('names.txt','wt');
assert(fid>=3,msg)
fprintf(fid,'ImageName\n')
fprintf(fid,'%s\n',S.name)
fclose(fid);
% Load files:
for k = 1:numel(S)
    Im = imread(fullfile(D,S(k).name));
    ...
end

This uses S.name to generate a comma-separated list, and so each filename gets printed to the textfile.

See also: https://www.mathworks.com/matlabcentral/answers/320713-how-to-operate-on-comma-separated-lists

[sidra Rafique]

It worked perfect.. Thanks alott

[sidra Rafique]

hi, Now i need to add another column next to the ImageName column named as DIameter. After calculating the diameter i actually made a simple change in your above suggested code that is:

   fprintf(fid,'ImageName, 'Diameter'\n');
   fprintf(fid,'%s%3.4f\n',S.name,d);

where d is the variable with diameter for each image. Instead of showing diameter of the respective image this code is showing 102.0000 diameter for all the images except last image.For last image it is showing correct diameter. i am unable to locate my mistake. need your help again.

[Stephen23]

C = {S.name};
C(2,:) = num2cell(d);
...
fprintf(fid,'%s%3.4f\n',C{:});

or use a loop.

[sidra Rafique]

i am getting an error "Cell contents reference from a non-cell array object." after embeding below code:

if true
  c={S.name};
  c(2,:)=num2cell(d);
  fprintf(fid, '%s%3.4f\r\n', d{:});
end

[Image Analyst]

d is not a cell. Why did you change C, like Stephen had, to a "d"?

[sidra Rafique]

Oh! thats my mistake. Sorry. this code is perfectly working for me. Thanks.

[sidra Rafique]

After applying below code

if true
  [fid,msg] = fopen('names.txt','wt');
  assert(fid>=3,msg);
  fprintf(fid, '%5s %3s\r\n','Imagename','Diameter');
  fprintf(fid, '%s\n',Imgs.name);
  c={S.name};
  c(2,:)=num2cell(d);
  fprintf(fid, '%3.4f\n',c{:});
  fclose(fid);
end
this working fine for ImageName but for diameter its showing 32715 diameter values. and its only showing diameter of some random 15 images and keep on repeating till 32715.

and if i apply below code as you have suggested

if true
  C = {S.name};
  C(2,:) = num2cell(d);
  ...
  fprintf(fid,'%s%3.4f\n',C{:});
end

my output is something like this frame_000078.6283 for all the 1000 images.(with same diameter) please guide me through this.

[Stephen23]

@sidra Rafique: your code duplicates printing the filenames, and you need to add a separator/delimiter character between the filename and the value. Try something like this:

c = {S.name};
c(2,:) = num2cell(d);
[fid,msg] = fopen('names.txt','wt');
assert(fid>=3,msg);
fprintf(fid, '%s,%s\n','Imagename','Diameter');
fprintf(fid, '%s,%3.4f\n',c{:});
fclose(fid);

Note how I used the comma as a delimiter, and the filenames are included in c, so you do not need to print them again.

[sidra Rafique]

still its not working. but i have used xlswrite() to save in excel instead of text document. and its working and its more simpler. Thanks for your help.

Answer 2

[Yuvaraj Venkataswamy]

Check below link. https://in.mathworks.com/matlabcentral/answers/333532-how-to-extract-and-save-frames-in-a-video

In your case you can use below command.

 if true
     imwrite(frames, fullfile(f_folder,sprintf ('%frame_04d.jpg', nFrame)));
  end

[sidra Rafique]

i am done with reading all the 1000 images(frame_0000, frame_0001, frame_0003...., frame_1000) from a folder using below code:

Directory= //path where images are located
Imgs = dir(fullfile(Directory,'*.jpg'));
for j=1:length(Imgs)
    Img = imread(fullfile(Directory,Imgs(j).name));  % Read image
end

but now i am still unable to make a text file consisting of names of all the read images with same name format in column.i.e;

ImageName
frame_0000
frame_0001
.
.
.

for that i am using below code:

fid = fopen('names.txt','w');
fprintf(fid, '%5s\n','Imagename');
fprintf(fid, '%i\n',j);
fclose(fid);

but its only showing last read image if i do %i but with %s its showing nothing.. please help me in finding solution.