Image Compression Tool

This MATLAB project provides an image compression tool that utilizes Fourier Transform for compressing images. The tool allows users to select multiple images, convert them to grayscale, compress them using Fourier Transform, and save the compressed images in various formats. Additionally, it enables users to convert the compressed images back to their original form using inverse Fourier Transform (IFFT).

Features

• Multi-Image Selection: Users can select multiple images for compression.
• Grayscale Conversion: Converts the selected images to grayscale before compression.
• Fourier Transform Compression: Applies Fourier Transform to compress the grayscale images.
• Customizable Compression Quality: Allows users to specify the compression quality for each image.
• Output Format Selection: Supports saving compressed images in PNG, JPG, or BMP formats.
• File Size Comparison: Displays the file sizes before and after compression.
• Decompression: Allows conversion of the compressed images back to their original form using IFFT.
• Save Compression Details: Users can save the details of the compression process in a MAT file.

Requirements

• MATLAB R2018b or later
• Image Processing Toolbox

Usage

1. Clone the Repository

git clone https://github.com/your-username/image-compression-tool.git
cd image-compression-tool

2. Run the MATLAB Script

Open MATLAB and run the script image_compression_tool.m.

3. Select Images

• A file selection dialog will appear. Choose the images you want to compress.
• Supported formats: JPG, PNG, BMP.

4. Set Compression Quality and Output Format

• For each selected image, a dialog will prompt you to enter the compression quality (0-100).
• Another dialog will prompt you to choose the output format (PNG, JPG, BMP).

5. View Results

• The script will display the original, grayscale, compressed (magnitude), and final compressed images.
• File sizes before and after compression will be shown.

6. Convert Back to Original Image

• A button will be provided for each image to convert the compressed image back to its original form using IFFT.

7. Save Compression Details

• A save dialog will appear, allowing you to save the compression details in a MAT file.

Code Overview

Main Script

% Initialize variables
inputImages = {};
grayscaleImages = {};
compressedImages = {};
compressionQualities = [];
outputFormats = {};
outputFileNames = {};

% Prompt to select multiple images
[fileNames, filePath] = uigetfile({'*.jpg;*.png;*.bmp', 'Image Files (*.jpg, *.png, *.bmp)'}, 'Select Image Files', 'MultiSelect', 'on');
if isequal(fileNames, 0)
    disp('User canceled the operation');
    return;
end

% Ensure fileNames is a cell array, even if only one file is selected
if ~iscell(fileNames)
    fileNames = {fileNames};
end

% Loop through selected images
for i = 1:numel(fileNames)
    % Read the selected image
    try
        inputImages{i} = imread(fullfile(filePath, fileNames{i}));
    catch ex
        disp(['Error: Unable to read ' fileNames{i}]);
        disp(getReport(ex));
        continue;
    end

    % Convert the input image to grayscale
    try
        grayscaleImages{i} = rgb2gray(inputImages{i});
    catch ex
        disp(['Error: Unable to convert ' fileNames{i} ' to grayscale.']);
        disp(getReport(ex));
        continue;
    end

    % Perform Fourier Transform for compression
    compressedImages{i} = fft2(grayscaleImages{i});
    
    % Prompt for compression quality
    prompt = ['Enter compression quality for ' fileNames{i} ' (0-100, default: 95): '];
    dlgtitle = 'Compression Quality';
    dims = [1 50];
    definput = {'95'};
    answer = inputdlg(prompt, dlgtitle, dims, definput);
    
    % Check if the user canceled input or provided an invalid value
    if isempty(answer)
        compressionQuality = 95; % Default quality
    else
        compressionQuality = str2double(answer{1});
        if isnan(compressionQuality) || compressionQuality < 0 || compressionQuality > 100
            disp('Invalid compression quality. Using default quality (95).');
            compressionQuality = 95; % Default quality
        end
    end
    compressionQualities(i) = compressionQuality;

    % Allow the user to choose the output format
    formats = {'png', 'jpg', 'bmp'}; % Supported formats
    [outputFormatIndex, ~] = listdlg('PromptString', ['Select an output format for ' fileNames{i} ':'], 'ListString', formats);
    if isempty(outputFormatIndex)
        outputFormat = 'png'; % Default to PNG
    else
        outputFormat = formats{outputFormatIndex};
    end
    outputFormats{i} = outputFormat;
    
    % Generate unique output filename
    [~, baseFileName, ~] = fileparts(fileNames{i});
    outputFileNames{i} = [baseFileName '_compressed.' outputFormat];
    
    % Save the compressed image
    if strcmpi(outputFormat, 'jpg')
        % For JPEG images, include 'Quality' parameter
        imwrite(uint8(abs(compressedImages{i})), outputFileNames{i}, 'jpg', 'Quality', compressionQuality);
    else
        % For other formats (e.g., PNG), remove 'Quality' parameter
        imwrite(uint8(abs(compressedImages{i})), outputFileNames{i});
    end
    
    % Calculate file sizes before and after compression using 'dir'
    inputFileInfo = dir(fullfile(filePath, fileNames{i}));
    compressedFileInfo = dir(outputFileNames{i});
    
    inputFileSize = inputFileInfo.bytes / 1024; % File size in KB
    compressedFileSize = compressedFileInfo.bytes / 1024; % File size in KB

    fprintf('File %d: %s\n', i, fileNames{i});
    fprintf('Input File Size: %.2f KB\n', inputFileSize);
    fprintf('Compressed File Size: %.2f KB\n', compressedFileSize);
end

% Display the images and compression details
for i = 1:numel(fileNames)
    figure('Name', ['Image Compression and Decompression - ' fileNames{i}]);
    subplot(2, 2, 1);
    imshow(inputImages{i});
    title(['Input Image (' fileNames{i} ') =>']);
    originalSizeText = uicontrol('Style', 'text', 'String', ['Original File Size: ' num2str(inputFileSize, '%.2f') ' KB'],...
        'Position', [80 10 250 20]);
    
    subplot(2, 2, 2);
    imshow(grayscaleImages{i});
    title(['Grayscale Image (' fileNames{i} ')']);
    
    subplot(2, 2, 3);
    imshow(abs(compressedImages{i}), []);
    title(['Compressed Image MAGNITUDE (' fileNames{i} ')']);
    
    subplot(2, 2, 4);
    compressedImageFile = imread(outputFileNames{i});
    imshow(compressedImageFile);
    title(['Compressed Image (' fileNames{i} ')']);
    compressedFileSizeText = uicontrol('Style', 'text', 'String', ['Compressed File Size: ' num2str(compressedFileSize, '%.2f') ' KB'],...
        'Position', [300 10 250 20]);
end

% Button to convert the compressed image back using IFFT
convertButtons = [];
for i = 1:numel(fileNames)
    convertButtons{i} = uicontrol('Style', 'pushbutton', 'String', ['Convert Back (' fileNames{i} ')'],...
        'Position', [10, 10 + (i - 1) * 40, 120, 30],...
        'Callback', {@convertBack, compressedImages{i}});
end

% Compression Ratio Calculation
compressionRatios = compressionQualities / 100; % Assuming quality is a percentage

% Save Dialog
[saveFileName, saveFilePath] = uiputfile({'*.mat', 'MAT File (*.mat)'}, 'Save Compression Details as MAT File');
if isequal(saveFileName, 0)
    disp('User canceled the save operation');
else
    save(fullfile(saveFilePath, saveFileName), 'fileNames', 'compressionRatios', 'outputFormats', 'outputFileNames');
    disp(['Compression details saved as ' saveFileName]);
end

% Function to convert the compressed image back using IFFT
function convertBack(~, ~, compressedImage)
    if isempty(compressedImage)
        disp('Compressed image not available.');
        return;
    end

    % Perform inverse Fourier Transform (IFFT) to get the uncompressed image
    uncompressedImage = ifft2(compressedImage);

    % Display the uncompressed image
    figure('Name', 'Uncompressed Image');
    imshow(abs(uncompressedImage), []);
    title('Uncompressed Image');
end

License

This project is licensed under the MIT License. See the LICENSE file for details.

Contributing

Contributions are welcome! Please open an issue or submit a pull request for any improvements or new features.

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Enjoy using the Image Compression Tool!