Распознавание штрих-кодов в PDF документе

В этом разделе

PDF документ может хранить штрих-код в растровой форме в графическом ресурсе PDF документа. Также PDF документ может хранить штрих-код в векторной форме в векторном содержимом PDF документа.

Распознавание штрих-кодов в изображении-ресурсе PDF документа

Для распознавания штрих-кодов в изображениях-ресурсах PDF документа необходимо извлечь изображения-ресурсы из PDF документа и распознать штрих-коды в извлеченных изображениях.

VintaSoft Barcode .NET SDK предоставляет класс Vintasoft.Barcode.PdfImageViewer, который позволяет извлекать изображения-ресурсы из PDF документа. Класс может извлечь изображение-ресурс из PDF документа, если изображение-ресурс сжат с помощью алгоритма компрессии ZIP, JPEG, CCITT3, CCITT4, LZW, Run Length и данные изображения-ресурса хранятся в цветовом пространстве DeviceGray, DeviceRGB, DeviceCMYK или Indexed.

VintaSoft Imaging .NET SDK с Плагинами позволяет извлекать любые (любое сжатие данных и любое цветовое пространство для данных изображения) изображения-ресурсы из PDF документа.

Пример: Вот пример, который показывает, как распознать штрих-коды в изображениях-ресурсах PDF документа с помощью класса Vintasoft.Barcode.PdfImageViewer из VintaSoft Barcode .NET SDK:

/// <summary>
/// Reads barcodes from image-resources of PDF document.
/// </summary>
/// <param name="fileName">A path to a PDF document.</param>
/// <param name="barcodeTypes">The types of barcodes, which must be recognized.</param>
static void ReadBarcodesFromPdfDocument(string fileName, Vintasoft.Barcode.BarcodeType barcodeTypes)
{
    // create the PdfImageViewer object and open PDF document
    using (Vintasoft.Barcode.PdfImageViewer pdfImageViewer = new Vintasoft.Barcode.PdfImageViewer(fileName))
    {
        // create the barcode reader
        using (Vintasoft.Barcode.BarcodeReader reader = new Vintasoft.Barcode.BarcodeReader())
        {
            // set barcode reader settings
            reader.Settings.ScanBarcodeTypes = barcodeTypes;

            // for each page of PDF document
            for (int i = 0; i < pdfImageViewer.PageCount; i++)
            {
                // get names of all image resources of page i
                string[] imageNames = pdfImageViewer.GetImageNames(i);
                // for each image resource of page i
                for (int k = 0; k < imageNames.Length; k++)
                {
                    System.Console.WriteLine(string.Format("Page {0}, image {1}: ", i, imageNames[k]));
                    Vintasoft.Imaging.VintasoftBitmap bitmap;
                    // get image of image resource
                    try
                    {
                        bitmap = pdfImageViewer.GetImage(i, imageNames[k]);
                    }
                    catch (System.Exception ex)
                    {
                        // not supported image format
                        System.Console.WriteLine(ex.Message);
                        continue;
                    }

                    // read barcodes from image
                    Vintasoft.Barcode.IBarcodeInfo[] barcodesInfo = reader.ReadBarcodes(bitmap);

                    // free image resource
                    bitmap.Dispose();

                    // output information about barcodes
                    if (barcodesInfo.Length == 0)
                    {
                        System.Console.WriteLine("No barcodes found.");
                    }
                    else
                    {
                        for (int j = 0; j < barcodesInfo.Length; j++)
                            System.Console.WriteLine(string.Format("[{0}] {1}", barcodesInfo[j].BarcodeType,
                                                                         barcodesInfo[j].Value));
                    }
                }
            }
        }
    }
}

VB.NET

''' <summary>
''' Reads barcodes from image-resources of PDF document.
''' </summary>
''' <param name="fileName">A path to a PDF document.</param>
''' <param name="barcodeTypes">The types of barcodes, which must be recognized.</param>
Private Shared Sub ReadBarcodesFromPdfDocument(fileName As String, barcodeTypes As Vintasoft.Barcode.BarcodeType)
    ' create the PdfImageViewer object and open PDF document
    Using pdfImageViewer As New Vintasoft.Barcode.PdfImageViewer(fileName)
        ' create the barcode reader
        Using reader As New Vintasoft.Barcode.BarcodeReader()
            ' set barcode reader settings
            reader.Settings.ScanBarcodeTypes = barcodeTypes

            ' for each page of PDF document
            For i As Integer = 0 To pdfImageViewer.PageCount - 1
                ' get names of all image resources of page i
                Dim imageNames As String() = pdfImageViewer.GetImageNames(i)
                ' for each image resource of page i
                For k As Integer = 0 To imageNames.Length - 1
                    System.Console.WriteLine(String.Format("Page {0}, image {1}: ", i, imageNames(k)))
                    Dim barcodeImage As Vintasoft.Imaging.VintasoftBitmap
                    ' get image of image resource
                    Try
                        barcodeImage = pdfImageViewer.GetImage(i, imageNames(k))
                    Catch ex As System.Exception
                        ' not supported image format
                        System.Console.WriteLine(ex.Message)
                        Continue For
                    End Try

                    ' read barcodes from image
                    Dim barcodesInfo As Vintasoft.Barcode.IBarcodeInfo() = reader.ReadBarcodes(barcodeImage)

                    ' free image resource
                    barcodeImage.Dispose()

                    ' output information about barcodes
                    If barcodesInfo.Length = 0 Then
                        System.Console.WriteLine("No barcodes found.")
                    Else
                        For j As Integer = 0 To barcodesInfo.Length - 1
                            System.Console.WriteLine(String.Format("[{0}] {1}", barcodesInfo(j).BarcodeType, barcodesInfo(j).Value))
                        Next
                    End If
                Next
            Next
        End Using
    End Using
End Sub

Пример: Вот пример, который показывает, как распознать штрих-коды в изображениях-ресурсах PDF документа с помощью VintaSoft Imaging .NET SDK:

/// <summary>
/// Reads barcodes from image-resources of PDF document.
/// </summary>
/// <param name="pdfFilename">A path to a PDF document.</param>
public static void ReadBarcodesFromPdfDocumentResources(string pdfFilename)
{
    // open PDF document
    using (Vintasoft.Imaging.Pdf.PdfDocument document = new Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename))
    {
        // for each PDF page
        for (int i = 0; i < document.Pages.Count; i++)
        {
            // get image resources of PDF page
            Vintasoft.Imaging.Pdf.Tree.PdfImageResource[] imageResources = document.Pages[i].GetImages();

            // foreach image resources
            for (int j = 0; j < imageResources.Length; j++)
            {
                // get image resource
                using (Vintasoft.Imaging.VintasoftImage imageResource = imageResources[j].GetImage())
                {
                    // get image of image resource
                    using (Vintasoft.Imaging.VintasoftBitmap bitmap = imageResource.GetAsVintasoftBitmap())
                    {
                        System.Console.WriteLine(string.Format("[Page {0}, resource {1}]", i + 1, j + 1));
                        // read barcodes from image
                        ReadBarcodesFromImage(bitmap);
                    }
                }
            }
        }
    }
}

/// <summary>
/// Reads barcodes from an image.
/// </summary>
/// <param name="barcodeImage">An image with barcodes.</param>
public static void ReadBarcodesFromImage(Vintasoft.Imaging.VintasoftBitmap barcodeImage)
{
    // create barcode reader
    using (Vintasoft.Barcode.BarcodeReader reader = new Vintasoft.Barcode.BarcodeReader())
    {
        // specify that reader must search for Code39, Code39Extended,
        // Code128, SSCC18 and DataMatrix barcodes
        reader.Settings.ScanBarcodeTypes =
            Vintasoft.Barcode.BarcodeType.Code39 |
            Vintasoft.Barcode.BarcodeType.Code128 |
            Vintasoft.Barcode.BarcodeType.DataMatrix;
        reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.Code39Extended);
        reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.SSCC18);

        // specify that reader must search for horizontal and vertical barcodes only
        reader.Settings.ScanDirection = Vintasoft.Barcode.ScanDirection.Horizontal | Vintasoft.Barcode.ScanDirection.Vertical;

        // use Automatic Recognition
        reader.Settings.AutomaticRecognition = true;

        // expected one barcode
        reader.Settings.ExpectedBarcodes = 1;

        // scan interval - 5 pixels
        reader.Settings.ScanInterval = 5;

        // read barcodes from image
        Vintasoft.Barcode.IBarcodeInfo[] infos = reader.ReadBarcodes(barcodeImage);

        // if barcodes are not detected
        if (infos.Length == 0)
        {
            System.Console.WriteLine("No barcodes found.");
        }
        // if barcodes are detected
        else
        {
            // get information about extracted barcodes

            System.Console.WriteLine(string.Format("{0} barcodes found:", infos.Length));
            System.Console.WriteLine();
            for (int i = 0; i < infos.Length; i++)
            {
                Vintasoft.Barcode.IBarcodeInfo info = infos[i];
                System.Console.WriteLine(string.Format("[{0}:{1}]", i + 1, info.BarcodeType));
                System.Console.WriteLine(string.Format("Value:      {0}", info.Value));
                System.Console.WriteLine(string.Format("Region:     {0}", info.Region));
                System.Console.WriteLine();
            }
        }
    }
}

VB.NET

''' <summary>
''' Reads barcodes from image-resources of PDF document.
''' </summary>
''' <param name="pdfFilename">A path to a PDF document.</param>
Public Shared Sub ReadBarcodesFromPdfDocumentResources(pdfFilename As String)
    ' open PDF document
    Using document As New Vintasoft.Imaging.Pdf.PdfDocument(pdfFilename)
        ' for each PDF page
        For i As Integer = 0 To document.Pages.Count - 1
            ' get image resources of PDF page
            Dim imageResources As Vintasoft.Imaging.Pdf.Tree.PdfImageResource() = document.Pages(i).GetImages()

            ' foreach image resources
            For j As Integer = 0 To imageResources.Length - 1
                ' get image resource
                Using imageResource As Vintasoft.Imaging.VintasoftImage = imageResources(j).GetImage()
                    ' get image of image resource
                    Using bitmap As Vintasoft.Imaging.VintasoftBitmap = imageResource.GetAsVintasoftBitmap()
                        System.Console.WriteLine(String.Format("[Page {0}, resource {1}]", i + 1, j + 1))
                        ' read barcodes from image
                        ReadBarcodesFromImage(bitmap)
                    End Using
                End Using
            Next
        Next
    End Using
End Sub

''' <summary>
''' Reads barcodes from an image.
''' </summary>
''' <param name="barcodeImage">An image with barcodes.</param>
Public Shared Sub ReadBarcodesFromImage(barcodeImage As Vintasoft.Imaging.VintasoftBitmap)
    ' create barcode reader
    Using reader As New Vintasoft.Barcode.BarcodeReader()
        ' specify that reader must search for Code39, Code39Extended,
        ' Code128, SSCC18 and DataMatrix barcodes
        reader.Settings.ScanBarcodeTypes = Vintasoft.Barcode.BarcodeType.Code39 Or Vintasoft.Barcode.BarcodeType.Code128 Or Vintasoft.Barcode.BarcodeType.DataMatrix
        reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.Code39Extended)
        reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.SSCC18)

        ' specify that reader must search for horizontal and vertical barcodes only
        reader.Settings.ScanDirection = Vintasoft.Barcode.ScanDirection.Horizontal Or Vintasoft.Barcode.ScanDirection.Vertical

        ' use Automatic Recognition
        reader.Settings.AutomaticRecognition = True

        ' expected one barcode
        reader.Settings.ExpectedBarcodes = 1

        ' scan interval - 5 pixels
        reader.Settings.ScanInterval = 5

        ' read barcodes from image
        Dim infos As Vintasoft.Barcode.IBarcodeInfo() = reader.ReadBarcodes(barcodeImage)

        ' if barcodes are not detected
        If infos.Length = 0 Then
            System.Console.WriteLine("No barcodes found.")
        Else
            ' if barcodes are detected
            ' get information about extracted barcodes

            System.Console.WriteLine(String.Format("{0} barcodes found:", infos.Length))
            System.Console.WriteLine()
            For i As Integer = 0 To infos.Length - 1
                Dim info As Vintasoft.Barcode.IBarcodeInfo = infos(i)
                System.Console.WriteLine(String.Format("[{0}:{1}]", i + 1, info.BarcodeType))
                System.Console.WriteLine(String.Format("Value:      {0}", info.Value))
                System.Console.WriteLine(String.Format("Region:     {0}", info.Region))
                System.Console.WriteLine()
            Next
        End If
    End Using
End Sub

Распознавание штрих-кодов в отрендеренном изображении PDF страницы

Для распознавания штрих-кодов в векторном контенте необходимо отрендерить PDF страницу и распознать штрих-коды в отрендеренном изображении.

PDF страница может быть отрендерена используя VintaSoft Imaging .NET SDK с Плагинами или с помощью любого другого стороннего программного обеспечения.

Пример: Вот пример, который показывает, как распознать штрих-коды в отрендеренной странице PDF документа используя VintaSoft Imaging .NET SDK:

/// <summary>
/// Reads barcodes from a vector PDF document.
/// </summary>
/// <param name="pdfFilename">A path to a PDF document.</param>
public static void ReadBarcodesFromVectorPDFDocument(string pdfFilename)
{
    // create the image collection
    using (Vintasoft.Imaging.ImageCollection pdfPages = new Vintasoft.Imaging.ImageCollection())
    {
        // add PDF document to the image collection
        pdfPages.Add(pdfFilename);

        // set the rendering settings to 200DPI, if necessary
        pdfPages.SetRenderingSettings(new Vintasoft.Imaging.Codecs.Decoders.RenderingSettings(new Vintasoft.Imaging.Resolution(200, 200)));

        // for each PDF page
        foreach (Vintasoft.Imaging.VintasoftImage image in pdfPages)
        {
            // get page image
            using (Vintasoft.Imaging.VintasoftBitmap pageImage = image.GetAsVintasoftBitmap())
            {
                // read barcodes from image
                ReadBarcodesFromImage(pageImage);
            }
        }

        // clear image collection
        pdfPages.ClearAndDisposeItems();
    }
}

/// <summary>
/// Reads barcodes from an image.
/// </summary>
/// <param name="barcodeImage">An image with barcodes.</param>
public static void ReadBarcodesFromImage(Vintasoft.Imaging.VintasoftBitmap barcodeImage)
{
    // create barcode reader
    Vintasoft.Barcode.BarcodeReader reader = new Vintasoft.Barcode.BarcodeReader();

    // specify that reader must search for Code39, Code39Extended,
    // Code128, SSCC18 and DataMatrix barcodes
    reader.Settings.ScanBarcodeTypes =
        Vintasoft.Barcode.BarcodeType.Code39 |
        Vintasoft.Barcode.BarcodeType.Code128 |
        Vintasoft.Barcode.BarcodeType.DataMatrix;
    reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.Code39Extended);
    reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.SSCC18);

    // specify that reader must search for horizontal and vertical barcodes only
    reader.Settings.ScanDirection = Vintasoft.Barcode.ScanDirection.Horizontal | Vintasoft.Barcode.ScanDirection.Vertical;

    // use Automatic Recognition
    reader.Settings.AutomaticRecognition = true;

    // read barcodes from image
    Vintasoft.Barcode.IBarcodeInfo[] infos = reader.ReadBarcodes(barcodeImage);

    // if barcodes are not detected
    if (infos.Length == 0)
    {
        System.Console.WriteLine("No barcodes found.");
    }
    // if barcodes are detected
    else
    {
        // get information about extracted barcodes

        System.Console.WriteLine(string.Format("{0} barcodes found:", infos.Length));
        System.Console.WriteLine();
        for (int i = 0; i < infos.Length; i++)
        {
            Vintasoft.Barcode.IBarcodeInfo info = infos[i];
            System.Console.WriteLine(string.Format("[{0}:{1}]", i + 1, info.BarcodeType));
            System.Console.WriteLine(string.Format("Value:      {0}", info.Value));
            System.Console.WriteLine(string.Format("Region:     {0}", info.Region));
            System.Console.WriteLine();
        }
    }
}

VB.NET

''' <summary>
''' Reads barcodes from a vector PDF document.
''' </summary>
''' <param name="pdfFilename">A path to a PDF document.</param>
Public Shared Sub ReadBarcodesFromVectorPDFDocument(pdfFilename As String)
    ' create the image collection
    Using pdfPages As New Vintasoft.Imaging.ImageCollection()
        ' add PDF document to the image collection
        pdfPages.Add(pdfFilename)

        ' set the rendering settings to 200DPI, if necessary
        pdfPages.SetRenderingSettings(New Vintasoft.Imaging.Codecs.Decoders.RenderingSettings(New Vintasoft.Imaging.Resolution(200, 200)))

        ' for each PDF page
        For Each image As Vintasoft.Imaging.VintasoftImage In pdfPages
            ' get page image
            Using pageImage As Vintasoft.Imaging.VintasoftBitmap = image.GetAsVintasoftBitmap()
                ' read barcodes from image
                ReadBarcodesFromImage(pageImage)
            End Using
        Next

        ' clear image collection
        pdfPages.ClearAndDisposeItems()
    End Using
End Sub

''' <summary>
''' Reads barcodes from an image.
''' </summary>
''' <param name="barcodeImage">An image with barcodes.</param>
Public Shared Sub ReadBarcodesFromImage(barcodeImage As Vintasoft.Imaging.VintasoftBitmap)
    ' create barcode reader
    Dim reader As New Vintasoft.Barcode.BarcodeReader()

    ' specify that reader must search for Code39, Code39Extended,
    ' Code128, SSCC18 and DataMatrix barcodes
    reader.Settings.ScanBarcodeTypes = Vintasoft.Barcode.BarcodeType.Code39 Or Vintasoft.Barcode.BarcodeType.Code128 Or Vintasoft.Barcode.BarcodeType.DataMatrix
    reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.Code39Extended)
    reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.SSCC18)

    ' specify that reader must search for horizontal and vertical barcodes only
    reader.Settings.ScanDirection = Vintasoft.Barcode.ScanDirection.Horizontal Or Vintasoft.Barcode.ScanDirection.Vertical

    ' use Automatic Recognition
    reader.Settings.AutomaticRecognition = True

    ' read barcodes from image
    Dim infos As Vintasoft.Barcode.IBarcodeInfo() = reader.ReadBarcodes(barcodeImage)

    ' if barcodes are not detected
    If infos.Length = 0 Then
        System.Console.WriteLine("No barcodes found.")
    Else
        ' if barcodes are detected
        ' get information about extracted barcodes

        System.Console.WriteLine(String.Format("{0} barcodes found:", infos.Length))
        System.Console.WriteLine()
        For i As Integer = 0 To infos.Length - 1
            Dim info As Vintasoft.Barcode.IBarcodeInfo = infos(i)
            System.Console.WriteLine(String.Format("[{0}:{1}]", i + 1, info.BarcodeType))
            System.Console.WriteLine(String.Format("Value:      {0}", info.Value))
            System.Console.WriteLine(String.Format("Region:     {0}", info.Region))
            System.Console.WriteLine()
        Next
    End If
End Sub

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