How can you compare pictures if they have different resolutions, but the drawing is the same?

  • 2
    Hello. The question is not quite with #, but more about algorithms. I advise you to read on Habré: №1 , №2 , №3 - A1essandro
  • You can lead to one resolution - then compare. - nick_n_a
  • As I understand it, you first need to compress / enlarge the image to the same size, and then compare? - SOCIOPATH

1 answer 1

AForge.NET can help with this problem .

Need to install the nuget package

Install-Package AForge.Imaging -Version 2.2.5

Here is an example of a small WinForms program comparing 2 images: one small, the other bigger.

 using AForge.Imaging; using System; using System.Drawing; using System.Windows.Forms; namespace FileComparerWinForms { public partial class Form1 : Form { private string largeFileName; private string smallFileName; private bool img1Selected; private bool img2Selected; public Form1() { InitializeComponent(); } private void Form1_Load(object sender, EventArgs e) { largePicBox.Visible = false; smallPicBox.Visible = false; btnCompare.Enabled = false; ShowStatus(""); } private void LinkLarge_Clicked(object sender, LinkLabelLinkClickedEventArgs e) { fileDialog.FileName = ""; fileDialog.Title = "Select large image"; fileDialog.Filter = "All images|*.jpg; *.bmp; *.png"; fileDialog.ShowDialog(); if (fileDialog.FileName.ToString() != "") { largeFileName = fileDialog.FileName.ToString(); largeLink.Text = largeFileName; largePicBox.Image = System.Drawing.Image.FromFile(largeFileName); largePicBox.Visible = true; img1Selected = true; } ValidateSelections(); } private void LinkSmall_Clicked(object sender, LinkLabelLinkClickedEventArgs e) { fileDialog.FileName = ""; fileDialog.Title = "Select small image"; fileDialog.Filter = "All images|*.jpg; *.bmp; *.png"; fileDialog.ShowDialog(); if (fileDialog.FileName.ToString() != "") { smallFileName = fileDialog.FileName.ToString(); smallLink.Text = smallFileName; smallPicBox.Image = System.Drawing.Image.FromFile(smallFileName); smallPicBox.Visible = true; img2Selected = true; } ValidateSelections(); } private void ValidateSelections() { ShowStatus(""); if (img1Selected && img2Selected) { btnCompare.Enabled = true; } } private void CompareBtn_Click(object sender, EventArgs e) { ShowStatus("Processing..."); Bitmap largeImage = (Bitmap)Bitmap.FromFile(largeFileName); Bitmap smallImage = (Bitmap)Bitmap.FromFile(smallFileName); // create template matching algorithm's instance // (set similarity threshold to 90%) ExhaustiveTemplateMatching tm = new ExhaustiveTemplateMatching(0.9f); // find all matchings with specified above similarity TemplateMatch[] matches = tm.ProcessImage(largeImage, smallImage); if (matches.Length > 0) { TemplateMatch match = matches[0]; ShowStatus("Match found at X: " + match.Rectangle.Location.X + "; Y:" + match.Rectangle.Location.Y); } else { ShowStatus("Match not found"); } } private void ShowStatus(string status) { outputMessage.Text = status; outputMessage.Invalidate(); outputMessage.Update(); outputMessage.Refresh(); } } }