Compare Images with Image Processing - WinForms C#

using System; 
using System.Drawing; 
using System.IO; 
using System.Windows.Forms; 
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Controls; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.ImageProcessing.Core; 
using Leadtools.ImageProcessing.Effects; 

private ImageViewer _viewer1; 
private ImageViewer _viewer2; 
private RasterCodecs _codecs; 
private RasterImage _image1; 
private RasterImage _image2; 

private void Form1_Load(object sender, EventArgs e) 
{ 
    try 
    { 
        _viewer1 = new ImageViewer(); 
        _viewer1.Dock = DockStyle.Fill; 
        _viewer1.BackColor = Color.DarkGray; 
        panel1.Controls.Add(_viewer1); 
        _viewer1.BringToFront(); 
        _viewer1.Zoom(ControlSizeMode.Fit, 1.0, _viewer1.DefaultZoomOrigin); 
 
        _viewer2 = new ImageViewer(); 
        _viewer2.Dock = DockStyle.Fill; 
        _viewer2.BackColor = Color.DarkGray; 
        panel2.Controls.Add(_viewer2); 
        _viewer2.BringToFront(); 
        _viewer2.Zoom(ControlSizeMode.Fit, 1.0, _viewer1.DefaultZoomOrigin); 
 
        _codecs = new RasterCodecs(); 
    } 
    catch (Exception ex) 
    { 
        MessageBox.Show(ex.ToString()); 
    } 
} 

private void btnLoadFirst_Click(object sender, EventArgs e) 
{ 
    try 
    { 
        string _filePath = GetFilePath(); 
        string _fileName = Path.GetFileName(_filePath); 
        _image1 = _codecs.Load(_filePath); 
        _viewer1.Image = _image1; 
        label1.Text = $"1st Image: {_fileName}"; 
    } 
    catch (Exception ex) 
    { 
        MessageBox.Show(ex.ToString()); 
    } 
} 

private void btnLoadSecond_Click(object sender, EventArgs e) 
{ 
    try 
    { 
        string _filePath = GetFilePath(); 
        string _fileName = Path.GetFileName(_filePath); 
        _image2 = _codecs.Load(_filePath); 
        _viewer2.Image = _image2; 
        label2.Text = $"2nd Image: {_fileName}"; 
    } 
    catch (Exception ex) 
    { 
        MessageBox.Show(ex.ToString()); 
    } 
} 

private string GetFilePath() 
{ 
    string _filePath = null; 
    OpenFileDialog dlg = new OpenFileDialog(); 
    dlg.InitialDirectory = @"C:\LEADTOOLS21\Resources\Images"; 
    if (dlg.ShowDialog(this) == DialogResult.OK) 
    { 
        _filePath = dlg.FileName; 
    } 
    return _filePath; 
} 

private void btnCompare_Click(object sender, EventArgs e) 
{ 
    if (_viewer1.Image == null || _viewer2.Image == null) 
    { 
        MessageBox.Show("Please load images first"); 
        return; 
    } 
    lstResult.Items.Add("************** Comparing... **************"); 
 
    int newItem; 
 
    // First measure: compare pixel-by-pixel by XOR-ing them 
    using (RasterImage dstImage = _image2.Clone()) 
    { 
        LeadRect rc = new LeadRect(0, 0, _viewer1.Image.Width, _viewer1.Image.Height); 
        CombineCommand combine = new CombineCommand(_image1, rc, new LeadPoint(0, 0), 
            CombineCommandFlags.OperationXor); 
        combine.Run(dstImage); 
        // Identical pixels will result in black after XOR. Next code will calculate black ratio in resulting image 
        // Define a region of all black pixels 
        dstImage.AddColorToRegion(RasterColor.Black, RasterRegionCombineMode.Set); 
        // Find the area of black region and divide by total image area 
        double percentBlack = dstImage.CalculateRegionArea() * 100.0 / (dstImage.Width * dstImage.Height); 
        newItem = lstResult.Items.Add(string.Format("Compare exact pixels: {0:N2}% identical", percentBlack)); 
        lstResult.TopIndex = newItem; 
    } 
 
    // Make grayscale copies to calculate intensity values 
    GrayscaleCommand gray = new GrayscaleCommand(8); 
    // Statistics info command will be used throughout to find average values of image pixels 
    StatisticsInformationCommand stats = new StatisticsInformationCommand(RasterColorChannel.Master, 0, 255); 
    using (RasterImage image2Gray = _image2.Clone()) 
    using (RasterImage image1Gray = _image1.Clone()) 
    { 
        LeadRect rc = new LeadRect(0, 0, image2Gray.Width, image2Gray.Height); 
        // To get intensity values alone, convert to grayscale 
        gray.Run(image1Gray); 
        gray.Run(image2Gray); 
 
        // Second measure: Overall intensity value 
        stats.Run(image1Gray); 
        double intensityAverage1 = stats.Mean; 
        stats.Run(image2Gray); 
        double intensityAverage2 = stats.Mean; 
        double AvgSimilarity = 100.0 - (Math.Abs(intensityAverage2 - intensityAverage1) * 100.0 / 255); 
        newItem = lstResult.Items.Add(string.Format("Overall image intensities: {0:N2}% similar", AvgSimilarity)); 
        lstResult.TopIndex = newItem; 
 
        // Third measure: pixel-wise intensity similarity  
        CombineCommand combine = new CombineCommand(image1Gray, rc, new LeadPoint(0, 0), 
            CombineCommandFlags.AbsoluteDifference); 
        combine.Run(image2Gray); 
        // The image2Gray now has the subtraction result of the 2 image's intensities. 
        // The Mean value will be the average of the intensities difference 
        stats.Run(image2Gray); 
        double pixelsSimilarity = 100.0 - (stats.Mean * 100.0 / 255); 
        newItem = lstResult.Items.Add(string.Format("Corresponding pixels intensities: {0:N2}% similar", 
            pixelsSimilarity)); 
        lstResult.TopIndex = newItem; 
    } 
 
    // Fourth and fifth measures: compare average hue and average saturation 
    // Color seprate to obtain Hue and Saturation planes 
    ColorSeparateCommand colorSep = new ColorSeparateCommand(ColorSeparateCommandType.Hsv); 
    colorSep.Run(_image1); 
    colorSep.DestinationImage.Page = 1; 
    stats.Run(colorSep.DestinationImage); 
    // Store average value of first hue plane 
    double averageHue1 = stats.Mean; 
    // Move from the Hue plane to the Saturation plane, which is in page 2 
    colorSep.DestinationImage.Page = 2; 
    stats.Run(colorSep.DestinationImage); 
    // Store average value of first saturation plane 
    double averageSat1 = stats.Mean; 
    // Perform color separation of second image 
    colorSep.Run(_image2); 
    colorSep.DestinationImage.Page = 1; 
    stats.Run(colorSep.DestinationImage); 
    // Store average value of second image's hue plane 
    double averageHue2 = stats.Mean; 
    // Move from the Hue plane to the Saturation plane, which is in page 2 
    colorSep.DestinationImage.Page = 2; 
    stats.Run(colorSep.DestinationImage); 
    // Store average value of second image's saturation plane 
    double averageSat2 = stats.Mean; 
    double HueDiff = Math.Abs(averageHue1 - averageHue2); 
    // If one hue is very high and the other is very low, they're actually 
    // Close to each other because 0 lies next to 255 
    if (HueDiff > 127) 
        HueDiff = Math.Abs(HueDiff - 254); 
    double SatDiff = Math.Abs(averageSat1 - averageSat2); 
    double hueSimilarity = (255 - HueDiff) * 100 / 255.0; 
    double satSimilarity = (255 - SatDiff) * 100 / 255.0; 
    lstResult.Items.Add(string.Format("Average hue values of 2 images: {0:N2}% similar", hueSimilarity)); 
    newItem = lstResult.Items.Add(string.Format("Average saturation values of 2 images: {0:N2}% similar", 
        satSimilarity)); 
    lstResult.TopIndex = newItem; 
    // 6th measure: fequency content deserves its own function 
    CompareFrequencyContent(_image1.Clone(), _image2.Clone()); 
} 

public void CompareFrequencyContent(RasterImage img1, RasterImage img2) 
{ 
    // Make sure the images are the same size 
    if ((img1.Width != img2.Width) || (img1.Height != img2.Height)) 
    { 
        SizeCommand sizecommand = new SizeCommand(256, 256, Leadtools.RasterSizeFlags.Bicubic); 
        sizecommand.Run(img1); 
        sizecommand.Run(img2); 
    } 
    // Use the same flags for both images 
    // Include the padding flag so that FFT will work with non power-of-2 size images 
    FastFourierTransformCommandFlags fftFlags = FastFourierTransformCommandFlags.FastFourierTransform 
        | FastFourierTransformCommandFlags.Gray | FastFourierTransformCommandFlags.PadOptimally; 
    // The 2 arrays to hold the FFT result 
    FourierTransformInformation FTArray1 = new FourierTransformInformation(img1, fftFlags); 
    FourierTransformInformation FTArray2 = new FourierTransformInformation(img2, fftFlags); 
    // Apply FFT to first image 
    FastFourierTransformCommand command = new FastFourierTransformCommand(FTArray1, fftFlags); 
    command.Run(img1); 
    // Apply FFT to second image 
    command.FourierTransformInformation = FTArray2; 
    command.Run(img2); 
    // Summation of difference between each frequency component magnitude and its counterpart from the other image 
    double magDiff = 0; 
    // Summation of the 2 magnitude values from both images for all frequency components 
    double magSum = 0; 
    int dataLen = FTArray1.Data.Length; 
    unsafe // Fastest way to process is to use the data pointer provided by the command 
    { 
        double* pData1 = (double*)FTArray1.DataPointer; 
        double* pData2 = (double*)FTArray2.DataPointer; 
 
        for (int i = 0; i < dataLen; ++i) 
        { 
            double r1 = *pData1; 
            ++pData1; 
            double i1 = *pData1; 
            ++pData1; 
            // Magnitude is the square root of the real and imaginary parts 
            double mag1 = Math.Sqrt(r1 * r1 + i1 * i1); 
            double r2 = *pData2; 
            ++pData2; 
            double i2 = *pData2; 
            ++pData2; 
            double mag2 = Math.Sqrt(r2 * r2 + i2 * i2); 
            // Tally the magnitude sums 
            magSum += (mag1 + mag2); 
            // Tally the magnitude differences 
            magDiff += Math.Abs(mag1 - mag2); 
        } 
    } 
    if (magSum == 0) 
        magSum = 1; // don't divide by zero 
    double freqSimilarity = (magSum - magDiff) * 100 / magSum; 
    int newItem = lstResult.Items.Add(string.Format("Frequency content of 2 images: {0:N2}% similar", freqSimilarity)); 
    lstResult.TopIndex = newItem; 
    img1.Dispose(); 
    img2.Dispose(); 
} 

private void btnCopy_Click(object sender, EventArgs e) 
{ 
    string listText = ""; 
    foreach (string txt in lstResult.Items) 
        listText += txt + Environment.NewLine; 
    if (listText == "") 
        return; 
    Clipboard.Clear(); 
    Clipboard.SetText(listText); 
    MessageBox.Show("Results copied to clipboard"); 
} 

private void btnClearList_Click(object sender, EventArgs e) 
{ 
    lstResult.Items.Clear(); 
}