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ImageLoadOptions Class

Represents a class that stores options for loading images.
Inheritance Hierarchy
SystemObject
  SautinSoft.DocumentLoadOptions
    SautinSoft.DocumentImageLoadOptions

Namespace: SautinSoft.Document
Assembly: SautinSoft.Document (in SautinSoft.Document.dll) Version: 2024.3.11
Syntax
public class ImageLoadOptions : LoadOptions

The ImageLoadOptions type exposes the following members.

Constructors
 NameDescription
Public methodImageLoadOptions Initializes a new instance of the ImageLoadOptions class.
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Properties
 NameDescription
Public propertyOCROptions Allows to specify options for OCR (optical character recognition) and enable it.
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Example

See Developer Guide: Recognize an image using Tesseract (free OCR library) and save the result as DOCX document

Recognize an image using Tesseract (free OCR library) and save the result as DOCX document using C#
using System.IO;
using SautinSoft.Document;
using System;
using SkiaSharp;

namespace Example
{
    class Program
    {
        static void Main(string[] args)
        {
            // Get your free 30-day key here:   
            // https://sautinsoft.com/start-for-free/

            RecognizeImage();
        }

        /// <summary>
        /// Recognize an image using Tesseract (free OCR library) and save the result as DOCX document.
        /// </summary>
        /// <remarks>
        /// Details: https://www.sautinsoft.com/products/document/help/net/developer-guide/ocr-image-using-tesseract-and-save-as-docx-net-csharp-vb.php
        /// </remarks>
        static void RecognizeImage()
        {
            // Here we'll recognize an image (perform OCR) containing a text on English, Russian and Vietnamese.
            // Next save the OCR result as a new DOCX document.

            // First steps:

            // 1. Download data files for English, Russian and Vietnamese languages.
            // Please download the files: eng.traineddata, rus.traineddata and vie.traineddata.
            // From here (good and fast): https://github.com/tesseract-ocr/tessdata_fast
            // or (best and slow): https://github.com/tesseract-ocr/tessdata_best

            // 2. Copy the files: eng.traineddata, rus.traineddata and vie.traineddata to
            // the folder "tessdata" in the Project root.

            // 3. Be sure that the folder "tessdata" also contains "pdf.ttf" file.

            // Let's start:
            string inpFile = @"..\..\..\image.png";
            string outFile = "Result1.docx";

            ImageLoadOptions lo = new ImageLoadOptions();
            lo.OCROptions.OCRMode = OCRMode.Enabled;

            // You can specify all Tesseract parameters inside the method PerformOCR.
            lo.OCROptions.Method = PerformOCRTesseract;
            DocumentCore dc = DocumentCore.Load(inpFile, lo);

            // Make all text visible after Tesseract OCR (change font color to Black).
            // The matter is that Tesseract returns OCR result PDF document with invisible text.
            // But with help of Document .Net, we can change the text color, 
            // char scaling and spacing to desired.
            foreach (Run r in dc.GetChildElements(true, ElementType.Run))
            {
                r.CharacterFormat.FontColor = SautinSoft.Document.Color.Black;
                r.CharacterFormat.Scaling = 100;
                r.CharacterFormat.Spacing = 0;
                r.CharacterFormat.Size = 12;
            }

            // Change the page size and add page margins.
            Section section = dc.Sections[0];
            section.PageSetup.PaperType = PaperType.Letter;
            section.PageSetup.Orientation = Orientation.Landscape;
            double m = LengthUnitConverter.Convert(5, LengthUnit.Millimeter, LengthUnit.Point);
            section.PageSetup.PageMargins = new PageMargins() { Top = m, Left = m, Right = m, Bottom = m };
            dc.Save(outFile);

            // Open the result for demonstration purposes.
            System.Diagnostics.Process.Start(new System.Diagnostics.ProcessStartInfo(outFile) { UseShellExecute = true });
        }
        public static byte[] PerformOCRTesseract(byte[] image)
        {
            // Specify that Tesseract use three 3 languages: English, Russian and Vietnamese.
            string tesseractLanguages = "rus+eng+vie";


            // A path to a folder which contains languages data files and font file "pdf.ttf".
            // Language data files can be found here:
            // Good and fast: https://github.com/tesseract-ocr/tessdata_fast
            // or
            // Best and slow: https://github.com/tesseract-ocr/tessdata_best
            // Also this folder must have write permissions.
            string tesseractData = Path.GetFullPath(@"..\..\..\tessdata\");

            // A path for a temporary PDF file (because Tesseract returns OCR result as PDF document)
            string tempFile = Path.Combine(tesseractData, Path.GetRandomFileName());

            try
            {
                using (Tesseract.IResultRenderer renderer = Tesseract.PdfResultRenderer.CreatePdfRenderer(tempFile, tesseractData, true))
                {
                    using (renderer.BeginDocument("Serachablepdf"))
                    {
                        using (Tesseract.TesseractEngine engine = new Tesseract.TesseractEngine(tesseractData, tesseractLanguages, Tesseract.EngineMode.Default))
                        {
                            engine.DefaultPageSegMode = Tesseract.PageSegMode.Auto;
                            using (MemoryStream msImg = new MemoryStream(image))
                            {
                                SKBitmap imgWithText = SKBitmap.Decode(msImg);
                                    using (MemoryStream ms = new MemoryStream())
                                    {
                                        imgWithText.Encode(ms, SKEncodedImageFormat.Png, 100);
                                        byte[] imgBytes = ms.ToArray();
                                        using (Tesseract.Pix img = Tesseract.Pix.LoadFromMemory(imgBytes))
                                        {
                                            using (var page = engine.Process(img, "Serachablepdf"))
                                            {
                                                renderer.AddPage(page);
                                            }
                                        }
                                    }
                            }
                        }
                    }
                }

                PdfLoadOptions pl = new PdfLoadOptions();
                pl.ShowInvisibleText = true;
                // 'Disabled' - Never load embedded fonts in PDF. Use the fonts with the same name installed at the system or similar by font metrics.
                // 'Enabled' - Always load embedded fonts in PDF.
                // 'Auto' - Load only embedded fonts missing in the system. In other case, use the system fonts.
                pl.PreserveEmbeddedFonts = PropertyState.Disabled;
                pl.ConversionMode = PdfConversionMode.Continuous;

                DocumentCore dc = DocumentCore.Load(File.OpenRead(tempFile + @".pdf"), pl);

                byte[] returnPdf;
                using (MemoryStream ms = new MemoryStream())
                {
                    PdfSaveOptions ps = new PdfSaveOptions();
                    dc.Save(ms, ps);
                    returnPdf = ms.ToArray();
                }
                return returnPdf;
            }
            catch (Exception e)
            {
                Console.WriteLine();
                Console.WriteLine("Please be sure that you have Language data files (*.traineddata) in your folder \"tessdata\"");
                Console.WriteLine("The Language data files can be download from here: https://github.com/tesseract-ocr/tessdata_fast");
                Console.ReadKey();
                throw new Exception("Error Tesseract: " + e.Message);
            }
            finally
            {
                if (File.Exists(tempFile + ".pdf"))
                    File.Delete(tempFile + ".pdf");
            }
        }
    }
}
Recognize an image using Tesseract (free OCR library) and save the result as DOCX document using VB.Net
Imports System
Imports System.IO
Imports SautinSoft.Document
Imports SkiaSharp

Module Sample
    Sub Main()
        RecognizeImage()
    End Sub
        ''' Get your free 30-day key here:   
        ''' https://sautinsoft.com/start-for-free/
    ''' <summary>
    ''' Recognize an image using Tesseract (free OCR library) and save the result as DOCX document.
    ''' </summary>
    ''' <remarks>
    ''' Details: https://www.sautinsoft.com/products/document/help/net/developer-guide/ocr-image-using-tesseract-and-save-as-docx-net-csharp-vb.php
    ''' </remarks>
    Sub RecognizeImage()
        ' Here we'll recognize an image (perform OCR) containing a text on English, Russian and Vietnamese.
        ' Next save the OCR result as a new DOCX document.

        ' First steps:

        ' 1. Download data files for English, Russian and Vietnamese languages.
        ' Please download the files: eng.traineddata, rus.traineddata and vie.traineddata.
        ' From here (good and fast): https://github.com/tesseract-ocr/tessdata_fast
        ' or (best and slow): https://github.com/tesseract-ocr/tessdata_best

        ' 2. Copy the files: eng.traineddata, rus.traineddata and vie.traineddata to
        ' the folder "tessdata" in the Project root.

        ' 3. Be sure that the folder "tessdata" also contains "pdf.ttf" file.

        ' Let's start:
        Dim inpFile As String = "..\..\..\image.png"
        Dim outFile As String = "Result.docx"

        Dim lo As New ImageLoadOptions()
        lo.OCROptions.OCRMode = OCRMode.Enabled

        ' You can specify all Tesseract parameters inside the method PerformOCR.
        lo.OCROptions.Method = AddressOf PerformOCRTesseract
        Dim dc As DocumentCore = DocumentCore.Load(inpFile, lo)

        ' Make all text visible after Tesseract OCR (change font color to Black).
        ' The matter is that Tesseract returns OCR result PDF document with invisible text.
        ' But with help of Document .Net, we can change the text color, 
        ' char scaling and spacing to desired.
        For Each r As Run In dc.GetChildElements(True, ElementType.Run)
            r.CharacterFormat.FontColor = SautinSoft.Document.Color.Black
            r.CharacterFormat.Scaling = 100
            r.CharacterFormat.Spacing = 0
            r.CharacterFormat.Size = 12
        Next r

        ' Change the page size and add page margins.
        Dim section As Section = dc.Sections(0)
        section.PageSetup.PaperType = PaperType.Letter
        section.PageSetup.Orientation = Orientation.Landscape
        Dim m As Double = LengthUnitConverter.Convert(5, LengthUnit.Millimeter, LengthUnit.Point)
        section.PageSetup.PageMargins = New PageMargins() With {
                .Top = m,
                .Left = m,
                .Right = m,
                .Bottom = m
            }


        dc.Save(outFile)

        ' Open the result for demonstration purposes.
        System.Diagnostics.Process.Start(New System.Diagnostics.ProcessStartInfo(outFile) With {.UseShellExecute = True})
    End Sub
    Public Function PerformOCRTesseract(ByVal image() As Byte) As Byte()
        ' Specify that Tesseract use three 3 languages: English, Russian and Vietnamese.
        Dim tesseractLanguages As String = "rus+eng+vie"

        ' A path to a folder which contains languages data files and font file "pdf.ttf".
        ' Language data files can be found here:
        ' Good and fast: https://github.com/tesseract-ocr/tessdata_fast
        ' or
        ' Best and slow: https://github.com/tesseract-ocr/tessdata_best
        ' Also this folder must have write permissions.
        Dim tesseractData As String = Path.GetFullPath("..\..\..\tessdata\")

        ' A path for a temporary PDF file (because Tesseract returns OCR result as PDF document)
        Dim tempFile As String = Path.Combine(tesseractData, Path.GetRandomFileName())

        Try
            Using renderer As Tesseract.IResultRenderer = Tesseract.PdfResultRenderer.CreatePdfRenderer(tempFile, tesseractData, True)
                Using renderer.BeginDocument("Serachablepdf")
                    Using engine As New Tesseract.TesseractEngine(tesseractData, tesseractLanguages, Tesseract.EngineMode.Default)
                        engine.DefaultPageSegMode = Tesseract.PageSegMode.Auto
                        Using msImg As New MemoryStream(image)
                            Dim imgWithText As SKBitmap = SKBitmap.Decode(msImg)
                            Using ms As New MemoryStream()
                                imgWithText.Encode(ms, SKEncodedImageFormat.Png, 100)
                                Dim imgBytes() As Byte = ms.ToArray()
                                Using img As Tesseract.Pix = Tesseract.Pix.LoadFromMemory(imgBytes)
                                    Using page = engine.Process(img, "Serachablepdf")
                                        renderer.AddPage(page)
                                    End Using
                                End Using
                            End Using
                        End Using
                    End Using
                End Using
            End Using

            Dim pl As New PdfLoadOptions()
            pl.ShowInvisibleText = True
            ' 'Disabled' - Never load embedded fonts in PDF. Use the fonts with the same name installed at the system or similar by font metrics.
            ' 'Enabled' - Always load embedded fonts in PDF.
            ' 'Auto' - Load only embedded fonts missing in the system. In other case, use the system fonts.            
            pl.PreserveEmbeddedFonts = PropertyState.Disabled
            pl.ConversionMode = PdfConversionMode.Continuous

            Dim dc As DocumentCore = DocumentCore.Load(File.OpenRead(tempFile & ".pdf"), pl)

            Dim returnPdf() As Byte
            Using ms As New MemoryStream()
                Dim ps As New PdfSaveOptions()
                dc.Save(ms, ps)
                returnPdf = ms.ToArray()
            End Using
            Return returnPdf
        Catch e As Exception
            Console.WriteLine()
            Console.WriteLine("Please be sure that you have Language data files (*.traineddata) in your folder ""tessdata""")
            Console.WriteLine("The Language data files can be download from here: https://github.com/tesseract-ocr/tessdata_fast")
            Console.ReadKey()
            Throw New Exception("Error Tesseract: " & e.Message)
        Finally
            If File.Exists(tempFile & ".pdf") Then
                File.Delete(tempFile & ".pdf")
            End If
        End Try
    End Function
End Module
See Also