How to read multiple text.jpg images in a loop?

i saved the images as text.jpg,text(1).jpg,text(2).jpg as indexes in a folder...while i running this following code in which the loop starts with i=1 to trainnumber which shows the error ..

function T = CreateDatabase(~)

% Align a set of face images (the training set T1, T2, ... , TM )

%

% Description: This function reshapes all 2D images of the training database

% into 1D column vectors. Then, it puts these 1D column vectors in a row to

% construct 2D matrix 'T'.

%

%

% Argument: TrainDatabasePath - Path of the training database

%

% Returns: T - A 2D matrix, containing all 1D image vectors.

% Suppose all P images in the training database

% have the same size of MxN. So the length of 1D

% column vectors is MN and 'T' will be a MNxP 2D matrix.

%

% See also: STRCMP, STRCAT, RESHAPE

% Original version by Amir Hossein Omidvarnia, October 2007

% Email: [e-mail]

%%%%%%%%%%%%%%%%%%%%%%%% File management

TrainFiles = dir('C:\Users\HP\Documents\MATLAB\Attendance\TrainDatabase\');

Train_Number = 0;

for i = 1:size(TrainFiles,1)

if not(strcmp(TrainFiles(i).name,'.')|strcmp(TrainFiles(i).name,'..')|strcmp(TrainFiles(i).name,'Thumbs.db'))

Train_Number = Train_Number + 1; % Number of all images in the training database

end

end

%%%%%%%%%%%%%%%%%%%%%%%% Construction of 2D matrix from 1D image vectors

T = [];

for i = 1 : Train_Number

% I have chosen the name of each image in databases as a corresponding

% number. However, it is not mandatory!

str = num2str(i);

str = strcat(str,'.jpg');

str = strcat('C:\Users\HP\Documents\MATLAB\Attendance\TrainDatabase\',str);

img = imread(str);

img = rgb2gray(img);

[irow, icol] = size(img);

temp = reshape(img',irow*icol,1); % Reshaping 2D images into 1D image vectors

T = [T, temp]; % 'T' grows after each turn

end

[Stephen23]

You wrote that your filenames are "text.jpg,text(1).jpg,text(2).jpg", but the error message clearly states that it tried to open a file named "1.jpg". So apparently you are generating the wrong filename in your code.

"How to read multiple text.jpg images in a loop?"

Use dir or sprintf, just like the examples in the documentation:

https://www.mathworks.com/help/matlab/import_export/process-a-sequence-of-files.html

Note that fullfile is recommended for creating file paths, rather than string concatenation.

Answer 1

[Meg Noah]

It might be easier if you use wildcard in the dir function, then the .db or .. won't be in the list of files in TrainFiles.

TrainFiles = dir('C:\Users\HP\Documents\MATLAB\Attendance\TrainDatabase\*.jpg');