Extraction doesn't return all text and images from .pdf file

[bbrodnik]

I tried your little changed demo code to test extraction of text and images in evaluation version from .pdf file. In many cases it works, but from some documents (like from attached one), it doesn't extract all of it's contents.

My code in C# is as follows:

Code: Select all

    static void Test(string fName)
    {
      //Create a pdf document.
      if (!File.Exists(fName))
      {
        Console.WriteLine($"File {fName} does not exist.");
        return;
      }

      PdfDocument doc = new PdfDocument();
      doc.LoadFromFile(fName);

      StringBuilder buffer = new StringBuilder();
      IList <Image> images = new List<Image>();

      foreach (PdfPageBase page in doc.Pages)
      {
        buffer.Append(page.ExtractText());
        foreach (Image image in page.ExtractImages())
        {
          images.Add(image);
        }
      }

      doc.Close();

      //save text
      var fName_Txt = fName + ".txt";
      File.WriteAllText(fName_Txt, buffer.ToString());

      //save image
      int index = 0;
      foreach (Image image in images)
      {
        var fNameImg = $"{fName}_img{index++}.png";
        image.Save(fNameImg, ImageFormat.Png);
      }

      //Launching the Text file.
      //System.Diagnostics.Process.Start(fName_Txt);
    }


Thank you for any suggestions.

[Annika.Zhou]

Hello,

Thanks for your inquiry.
I noticed the behavior that the text cannot be extracted from your PDF document. After investigation, I found the contents in your file actully are paths which are made up of lines rather than real text. If you use Adobe to extract, it will also return empty text. Hence, this behavior is caused by your PDF document itself, sorry our Spire.PDF can't deal with it. Hope you can understand.

Sincerely,
Annika
E-iceblue support team

[bbrodnik]

I understand that there is no text inside document, but contents in neither extracted as images. How can I extract contents which is shown when opened with Adobe, even as image, to be able to perform OCR on it?

[Annika.Zhou]

Hello,

Thanks for your feedback.
You could use our Spire.PDF to convert Pdf pages to images, then use OCR to extract the text from the images. Please refer to the code below.

Code: Select all

            PdfDocument pdf = new PdfDocument();
            pdf.LoadFromFile("test.pdf");
            for (int i = 0; i < pdf.Pages.Count; i++)
            {
                String fileName = String.Format("img-{0}.png", i);
                using (Image image = pdf.SaveAsImage(i, 300, 300))
                {
                    image.Save(fileName, System.Drawing.Imaging.ImageFormat.Png);
                }
            }
            pdf.Close();

Sincerely,
Annika
E-iceblue support team