VintaSoft Imaging .NET SDK v8.7
Vintasoft.Imaging.FormsProcessing Namespace / FormRecognitionManager Class / RecognizeAsync Method
The task that defines parameters of forms recognition.
Example



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    RecognizeAsync Method
    In This Topic
    Recognizes forms in the specified image asynchronously.
    Syntax
    'Declaration
     
    Public Sub RecognizeAsync( _
       ByVal task As FormRecognitionTask _
    ) 
    public void RecognizeAsync( 
       FormRecognitionTask task
    )
    public: void RecognizeAsync( 
       FormRecognitionTask* task
    ) 
    public:
    void RecognizeAsync( 
       FormRecognitionTask^ task
    ) 

    Parameters

    task
    The task that defines parameters of forms recognition.
    Remarks
    This method is thread-safe.

    Important! Events RecognitionStarted, RecognitionFinished, ImageRecognitionStarted, ImageRecognitionFinished and RecognitionProgress are not raised during execution of this method.
    Task events FormRecognitionTask.Started, FormRecognitionTask.Finished, FormRecognitionTask.ImageRecognitionStarted, FormRecognitionTask.ImageRecognitionFinished and FormRecognitionTask.Progress must be used if events are necessary.

    Forms recognition will be performed in multiple threads if MaxThreads value is greater than 1.
    Example
    This example shows how to identify and recognize several forms asynchronously.
    ''' <summary>
    ''' Recognizes array of images synchronously.
    ''' </summary>
    ''' <param name="templateManager">The template manager.</param>
    ''' <param name="images">The images.</param>
    Public Shared Sub RecognizeImagesSync(templateManager As Vintasoft.Imaging.FormsProcessing.FormRecognition.FormTemplateManager, images As Vintasoft.Imaging.VintasoftImage())
        ' create template matching command
        Dim templateMatching As New Vintasoft.Imaging.FormsProcessing.TemplateMatching.TemplateMatchingCommand()
        ' set minimal confidence
        templateMatching.MinConfidence = 0.6F
        ' set template images
        templateMatching.TemplateImages = templateManager.TemplateImages
        ' create recognition manager
        Dim recognitionManager As New Vintasoft.Imaging.FormsProcessing.FormRecognitionManager(templateMatching, templateManager)
                
        ' if your form template contains OCR fields,
        ' make sure OCR engine manager is initialized before recognition
        ' (otherwise recognition will return null (Nothing)),
        ' see OCR field recognition examples
                
        ' subscribe to ImageRecognitionError event to output recognition errors
        AddHandler recognitionManager.ImageRecognitionError, AddressOf manager_ImageRecognitionError
        ' recognize the images
        Dim recognitionResults As Vintasoft.Imaging.FormsProcessing.FormRecognitionResult() = recognitionManager.Recognize(images)
        ' unsubscribe from ImageRecognitionError event
        RemoveHandler recognitionManager.ImageRecognitionError, AddressOf manager_ImageRecognitionError
        ' for each recognition result
        For i As Integer = 0 To recognitionResults.Length - 1
            System.Console.WriteLine(String.Format("Image {0} of {1}:", i + 1, recognitionResults.Length))
            System.Console.WriteLine()
                
            Dim recognitionResult As Vintasoft.Imaging.FormsProcessing.FormRecognitionResult = recognitionResults(i)
                
            ' if recognition failed with error (see ImageRecognitionError event handler output)
            If recognitionResult Is Nothing Then
                Continue For
            End If
                
            ' get the result of image comparison
            Dim imageCompareResult As Vintasoft.Imaging.FormsProcessing.TemplateMatching.ImageImprintCompareResult = recognitionResult.TemplateMatchingResult.ImageCompareResult
            ' if result is not reliable
            If Not imageCompareResult.IsReliable Then
                ' matching template is not found
                System.Console.WriteLine("Matching template is not found.")
            Else
                ' get recognized page
                Dim recognizedPage As Vintasoft.Imaging.FormsProcessing.FormRecognition.FormPage = recognitionResult.RecognizedPage
                ' write page info
                System.Console.WriteLine(String.Format("Matching template: {0}; confidence: {1:F1}%.", recognizedPage.Name, imageCompareResult.Confidence * 100))
                
                ' get form field count
                If recognizedPage.Items.Count = 0 Then
                    System.Console.WriteLine("No form fields were recognized.")
                Else
                    System.Console.WriteLine(String.Format("Recognized form field count: {0}", recognizedPage.Items.Count))
                    ' for each recognized form field
                    For Each recognizedField As Vintasoft.Imaging.FormsProcessing.FormRecognition.FormField In recognizedPage.Items
                        ' write field info
                        System.Console.WriteLine(String.Format("  Name: {0}; value: {1}; confidence: {2:F1}%", recognizedField.Name, recognizedField.Value, recognizedField.Confidence * 100))
                    Next
                End If
            End If
                
            System.Console.WriteLine()
            System.Console.WriteLine()
        Next
    End Sub
                
    ''' <summary>
    ''' Handles the ImageRecognitionError event of the FormRecognitionManager.
    ''' </summary>
    Private Shared Sub manager_ImageRecognitionError(sender As Object, e As Vintasoft.Imaging.FormsProcessing.FormRecognitionErrorEventArgs)
        System.Console.WriteLine(e.Exception.Message)
    End Sub
    /// <summary>
    /// Recognizes array of images synchronously.
    /// </summary>
    /// <param name="templateManager">The template manager.</param>
    /// <param name="images">The images.</param>
    public static void RecognizeImagesSync(
        Vintasoft.Imaging.FormsProcessing.FormRecognition.FormTemplateManager templateManager, 
        Vintasoft.Imaging.VintasoftImage[] images)
    {
        // create template matching command
        Vintasoft.Imaging.FormsProcessing.TemplateMatching.TemplateMatchingCommand templateMatching = 
            new Vintasoft.Imaging.FormsProcessing.TemplateMatching.TemplateMatchingCommand();
        // set minimal confidence
        templateMatching.MinConfidence = 0.6f;
        // set template images
        templateMatching.TemplateImages = templateManager.TemplateImages;
        // create recognition manager
        Vintasoft.Imaging.FormsProcessing.FormRecognitionManager recognitionManager = 
            new Vintasoft.Imaging.FormsProcessing.FormRecognitionManager(
                templateMatching, templateManager);
                
        // if your form template contains OCR fields,
        // make sure OCR engine manager is initialized before recognition
        // (otherwise recognition will return null (Nothing)),
        // see OCR field recognition examples
                
        // subscribe to ImageRecognitionError event to output recognition errors
        recognitionManager.ImageRecognitionError += manager_ImageRecognitionError;
        // recognize the images
        Vintasoft.Imaging.FormsProcessing.FormRecognitionResult[] recognitionResults = recognitionManager.Recognize(images);
        // unsubscribe from ImageRecognitionError event
        recognitionManager.ImageRecognitionError -= manager_ImageRecognitionError;
        // for each recognition result
        for (int i = 0; i < recognitionResults.Length; i++)
        {
            System.Console.WriteLine(string.Format(
                "Image {0} of {1}:",
                i + 1,
                recognitionResults.Length));
            System.Console.WriteLine();
                
            Vintasoft.Imaging.FormsProcessing.FormRecognitionResult recognitionResult = recognitionResults[i];
                
            // if recognition failed with error (see ImageRecognitionError event handler output)
            if (recognitionResult == null)
                continue;
                
            // get the result of image comparison
            Vintasoft.Imaging.FormsProcessing.TemplateMatching.ImageImprintCompareResult imageCompareResult =
                recognitionResult.TemplateMatchingResult.ImageCompareResult;
            // if result is not reliable
            if (!imageCompareResult.IsReliable)
            {
                // matching template is not found
                System.Console.WriteLine("Matching template is not found.");
            }
            else
            {
                // get recognized page
                Vintasoft.Imaging.FormsProcessing.FormRecognition.FormPage recognizedPage = recognitionResult.RecognizedPage;
                // write page info
                System.Console.WriteLine(string.Format(
                    "Matching template: {0}; confidence: {1:F1}%.",
                    recognizedPage.Name,
                    imageCompareResult.Confidence * 100));
                
                // get form field count
                if (recognizedPage.Items.Count == 0)
                {
                    System.Console.WriteLine("No form fields were recognized.");
                }
                else
                {
                    System.Console.WriteLine(string.Format(
                        "Recognized form field count: {0}",
                        recognizedPage.Items.Count));
                    // for each recognized form field
                    foreach (Vintasoft.Imaging.FormsProcessing.FormRecognition.FormField recognizedField in recognizedPage.Items)
                    {
                        // write field info
                        System.Console.WriteLine(string.Format(
                            "  Name: {0}; value: {1}; confidence: {2:F1}%",
                            recognizedField.Name,
                            recognizedField.Value,
                            recognizedField.Confidence * 100));
                    }
                }
            }
                
            System.Console.WriteLine();
            System.Console.WriteLine();
        }
    }
                
    /// <summary>
    /// Handles the ImageRecognitionError event of the FormRecognitionManager.
    /// </summary>
    static void manager_ImageRecognitionError(object sender, 
        Vintasoft.Imaging.FormsProcessing.FormRecognitionErrorEventArgs e)
    {
        System.Console.WriteLine(e.Exception.Message);
    }
    Requirements

    Target Platforms: Windows 10, Windows 8, Windows 7, Windows Vista, Windows XP, Windows Server 2012, Windows Server 2008, Windows Server 2003

    See Also