Problem to load tiff files using for loop

Hi all,

I would like to reshape several (N = 12) tiff files and do that through a for loop to go quicker than doing it one by one. Find below the code I wrote, however an error appeared, which said that only Mat and ASCII can be open this way. DOes anybody knows how to do it for .tiff files, please?

Error using load

Unable to read file

'E:\Data_emodnet_fisheries\Vessel_density\2017_01_st_01.tif'. Input

must be a MAT-file or an ASCII file containing numeric data with

same number of columns in each row.

Error in code (line 15)

t = load(fullfile(cd, file));

Regards

close all
clear all
clc

% assign the path to your working directory:
cd ('E:\Data_emodnet_fisheries\Vessel_density\');

file = '2017_##_st_01.tif';
file1 = '##.mat';
 for it = 1:12
     
   file(6:7) = sprintf('%02.0f',it);
   file1(1:2) = sprintf('%02.0f',it);

   t = load(fullfile(cd, file));
 
   imageData = read(t);

   new_lim = imageData(2700:4000, 3500:4700);

   save(file1,'new_lim');
 end

[Mathieu NOE]

hello

FYI - adapt to your own needs...

all the best

% select appropriate options below and adapt code to your specific needs ...

% files = dir('*.tif');      % all tif files in current directory
files = dir('handheld*.tif');      % as example : only tiff files with "handheld" in the filename

% resize options (sacle factor or pixels)
scale_factor = 0.5;

% select portion of the image
% 451*279*3. I will like to extract a portion with dimensions of 120*80*3
x_dim = 120;
y_dim = 80;
x_offset = 100; % please make sure the "corner" of the cropped image is correct
y_offset = 50;

% main loop
for ck = 1:length(files)
    Filename = files(ck).name;
    img = imread(Filename);
    
    % resize
    H{ck}= imresize(img, scale_factor);

    % select (crop)
    H{ck}= img(x_offset+(1:x_dim),y_offset+(1:y_dim),: );

    % plot (just to check)
    figure(ck), imagesc(H{ck});
    
    % insert your own code here (save for example)
    
end

[Jan]

The brute clearing header "close all, clear all, clc" is rarely useful. Especially clear all has no benefit, but wastes a lot of time.

"which said that only Mat and ASCII can be open this way" - please post a copy of the error message, because the details matter. This is much better than paraphrasing the message.

[Jonathan Demmer]

The entire error message is copied below this sentence...

Answer 1

[Jan]

load() works with MAT files and some text formats only. If you want to load an image file, use imread().

Using CD to change the current directory is less stable than using the absolute file path. Especially fullfile(cd, file) is a fragile overkill.

folder = 'E:\Data_emodnet_fisheries\Vessel_density\';
fmt    = '2017_%02d_st_01.tif';
for it = 1:12     
   imageFile = fullfile(folder, sprintf(fmt, it));
   imageData = imread(imageFile);
   new_lim   = imageData(2700:4000, 3500:4700, :);  % RGB data have 3 dimensions
   
   matFile   = fullfile(folder, sprintf('%02d.mat', it));
   save(matFile, 'new_lim');
   % Or: imwrite(new_lim, file) ???
 end

[Jonathan Demmer]

Thank you very much it works perfectly fine!