How can i extract and save LBP features of multiple images, so that i can use them as a DB features ?

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nissrine Neyy
nissrine Neyy 2020-12-25
评论： Image Analyst 2022-6-27
Hii, I have a folder of 200 images, I want to extract the LBP features of each image and save them in an Excel sheet so that I can use them as a DB features and retrieve, based on them, the accurate images in a CBIR project. I used this code for the extraction but the output gives me the feature vector of only one image.
image_folder = 'C:\Users\Desktop\images\resized';
ext_img = '*.png';
files = dir(fullfile(image_folder, ext_img));
assert(numel(files) > 0, 'No file was found. Check that the path is correct');
my_img = struct('img', cell(size(files)));
for i = 1:numel(files)
Img = imread(fullfile(image_folder, files(i).name));
gray = rgb2gray(Img);
LBP_image = extractLBPFeatures(gray,'Cellsize',[32 32], 'Normaas i lization','None');
numNeigbors = 8 %%Reshape the LBP features into a number of neighbors -by- number of cells array to access histograms for each individual cell.
numBins = numNeigbors*(numNeigbors-1)+3;
Cell_Hists = reshape(LBP_image,numBins,[]);
Cell_Hists = bsxfun(@rdivide,Cell_Hists,sum(Cell_Hists));%Normalize each LBP cell histogram using L1 norm
LBP_image = reshape(Cell_Hists,1,[]);%Reshape the LBP features vector back to 1-by- N feature vector
end
My second question is how to store them in Excel (in order to have the feature vectors of the 200 images). I used the xlswrite() function but as I said it gives me the vector of only one images (the last one) with a size of 1x3776.
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Lee Hau
Lee Hau 2022-6-27
Hi, I have 100 images in my file to be extracted. I have used the coding shown but still not able to display all 100 LBP features. Below is the coding I use.
image_folder = 'C:\Users\HP\Desktop\ABC\A';
if ~isfolder(image_folder)
errorMessage = sprintf('Error: Folder not found:\n%s', image_folder);
fprintf('%s\n', errorMessage);
errordlg(errorMessage);
return;
end
ext_img = '*.png';
files = dir(fullfile(image_folder, ext_img));
assert(numel(files) > 0, 'No file was found. Check that the path is correct');
my_img = struct('img', cell(size(files)));
numberOfFiles = 100;%numel(files);
results = zeros(numberOfFiles);
for k = 1 : numberOfFiles
baseFileName = files(k).name;
fullFileName = fullfile(files(k).folder, baseFileName);
thisImage = imread(fullFileName);
grayImage = rgb2gray(thisImage);
LBP_image = extractLBPFeatures(grayImage,'CellSize',[32 32],'Normalization','None');
numNeigbors = 8;
Cell_Hists = reshape(LBP_image,numBins,[]);
Cell_Hists = bsxfun(@rdivide,Cell_Hists,sum(Cell_Hists));
results(k, :) = reshape(Cell_Hists,1,[]);
end
if numberOfFiles >= 0
writematrix(LBP_image,results);
end
Below error showed when I run the coding.
Unable to perform assignment because the size of the left side is 1-by-100 and the size of the right side is 1-by-59.
Error in array (line 25)
results(k, :) = reshape(Cell_Hists,1,[]);
Image Analyst
Image Analyst 2022-6-27
@Lee Hau declare results with the right number of bins before the loop
numNeigbors = 8 %%Reshape the LBP features into a number of neighbors -by- number of cells array to access histograms for each individual cell.
numBins = numNeigbors*(numNeigbors-1)+3;
results = zeros(numberOfFiles, numBins);

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Image Analyst
Image Analyst 2020-12-26
That code is not very robust at all. Mainly you need to preallocate a matrix for LPB_image and load the results for each image into the proper row of LBP_image. And only write the workbook if there were some files found. So you need to do (as a start):
image_folder = 'C:\Users\Desktop\images\resized';
if ~isfolder(image_folder)
errorMessage = sprintf('Error: Folder not found:\n%s', image_folder);
fprintf('%s\n', errorMessage);
errordlg(errorMessage);
return;
end
ext_img = '*.png';
files = dir(fullfile(image_folder, ext_img));
assert(numel(files) > 0, 'No file was found. Check that the path is correct');
my_img = struct('img', cell(size(files)));
numberOfFiles = numel(files);
LBP_image = zeros(numberOfFiles, 3776); % Preallocate a row for every file.
for k = 1 : numberOfFiles
baseFileName = files(k).name;
fullFileName = fullfile(files(k).folder, baseFileName);
fprintf('Processing image #%d of %d : "%s"\n', k, numberOfFiles, baseFileName);
thisImage = imread(fullFileName);
% Convert to gray scale, if needed.
if ndims(thisImage) > 2
grayImage = rgb2gray(thisImage);
else
% Already gray scale so no conversion needed.
grayImage = thisImage;
end
% Compute LBP features.
LBP_image = extractLBPFeatures(grayImage, 'Cellsize',[32 32], 'Normaas i lization','None');
numNeigbors = 8; %%Reshape the LBP features into a number of neighbors -by- number of cells array to access histograms for each individual cell.
numBins = numNeigbors * (numNeigbors-1) + 3;
Cell_Hists = reshape(LBP_image,numBins,[]);
Cell_Hists = bsxfun(@rdivide,Cell_Hists,sum(Cell_Hists));%Normalize each LBP cell histogram using L1 norm
% Assign the results of this image, a 3776 row vector, to the proper row in our output.
LBP_image(k, :) = reshape(Cell_Hists,1,[]);%Reshape the LBP features vector back to 1-by- N feature vector
end
if numberOfFiles >= 0
xlswrite(fileName, LBP_image);
end
Of course there is lots more you could do to improve this code (add comments, alert the user if no files were found, etc.)
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Jarin Ritu
Jarin Ritu 2021-6-17
@nissrine Neyy can you share your update code?I'm getting this error -
Unable to perform assignment because the size of the left side is 1-by-3776 and the size of the right side is
1-by-343852.
Image Analyst
Image Analyst 2021-6-17
@Jarin Ritu, then why didn't you share your code? Attach it in a new question. You didn't even tell us the line of code that threw that error. So in the new question put all the red text, not just part of it.

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