Reconnaissance de la date de naissance dans une feuille OMR à bulles avec .NET

VintaSoft Imaging .NET SDK, complété par VintaSoft Forms Processing .NET Plug-in, permet de reconnaître les marques optiques (OMR) sur les formulaires remplis.

Cet article explique comment reconnaître la date de naissance à partir de l'image d'un formulaire OMR.

Voici l'image du modèle de formulaire OMR pour la saisie de la date de naissance:


Avant de reconnaître le formulaire OMR, il est nécessaire de créer un modèle de page de formulaire définissant tous les champs présents sur la page:

1. Créer un modèle de tableau regroupant les repères optiques pour la saisie du premier chiffre de la date de naissance
2. Créer un modèle de tableau regroupant les repères optiques pour la saisie du deuxième chiffre de la date de naissance
3. Créer un modèle de groupe de champs pour la date de naissance en fusionnant les modèles de tableau pour le premier et le deuxième chiffre
4. Créer un modèle de tableau regroupant les repères optiques pour la saisie du mois de la date de naissance
5. Créer un modèle de tableau regroupant les repères optiques pour la saisie des deux premiers chiffres de l'année de naissance
6. Créer un modèle de tableau, qui unit les marques optiques pour la saisie des deux derniers chiffres de l'année de naissance
7. Créer un modèle de groupe de champs pour l'année de naissance en fusionnant les modèles de tableau pour la première et la dernière paire de chiffres de l'année de naissance
8. Créer un modèle de groupe de champs pour la date de naissance en fusionnant les modèles de tableau pour le jour,mois et année
9. Créez un modèle de formulaire de page et ajoutez-y le modèle du groupe de champs de date de naissance

Voici le code C# montrant comment créer un modèle de page de formulaire sur lequel se trouvent des champs OMR avec des informations sur une date de naissance:

/// <summary>
/// Creates a page template with birth date.
/// </summary>
/// <returns>A page template with birth date.</returns>
private static Vintasoft.Imaging.FormsProcessing.FormRecognition.FormPageTemplate CreatePageTemplateWithBirthDate()
{
    // create an OMR field template table for the first digit of day
    Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrFieldTemplateTable dayPart1Template = CreateTemplateTableForFirstDigitInDay();
    // create an OMR field template table for the second digit of day
    Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrFieldTemplateTable dayPart2Template = CreateTemplateTableForSecondDigitInDay();
    // create a form field template group for day
    Vintasoft.Imaging.FormsProcessing.FormRecognition.FormFieldTemplateGroup dayTemplate = CreateTemplateGroup(
        "Day", "{0}{1}", dayPart1Template, dayPart2Template);


    // create an OMR field template table for month
    Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrFieldTemplateTable monthTemplate = CreateTemplateTableForMonth();


    // create an OMR field template table for the first 2 digits of year
    Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrFieldTemplateTable yearPart1Template = CreateTemplateTableForFirstTwoDigitsInYear();
    // create an OMR field template table for the last 2 digits of year
    Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrFieldTemplateTable yearPart2Template = CreateTemplateTableForLastTwoDigitsInYear();
    // create a form field template group for year
    Vintasoft.Imaging.FormsProcessing.FormRecognition.FormFieldTemplateGroup yearTemplate = CreateTemplateGroup(
        "Year", "{0}{1}", yearPart1Template, yearPart2Template);


    // create birth date template as a group of day, month and year templates
    Vintasoft.Imaging.FormsProcessing.FormRecognition.FormFieldTemplateGroup dateOfBirthTemplate = CreateTemplateGroup(
        "Date of Birth", "{0}.{1}.{2}", dayTemplate, monthTemplate, yearTemplate);


    // create an empty page template
    Vintasoft.Imaging.FormsProcessing.FormRecognition.FormPageTemplate pageTemplate =
        new Vintasoft.Imaging.FormsProcessing.FormRecognition.FormPageTemplate();

    // add birth date template to the page template
    pageTemplate.Items.Add(dateOfBirthTemplate);

    return pageTemplate;
}

/// <summary>
/// Creates an OMR field template table for the first digit of day.
/// </summary>
/// <returns>An OMR field template table for the first digit of day.</returns>
private static Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrFieldTemplateTable CreateTemplateTableForFirstDigitInDay()
{
    // create template table
    Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrFieldTemplateTable result =
        new Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrFieldTemplateTable();

    // update table properties
    result.Name = "D1";
    result.ColumnCount = 1;
    result.RowCount = 4;
    result.Orientation = Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrTableOrientation.Vertical;
    result.DistanceBetweenColumns = 0.2f;
    result.DistanceBetweenRows = 0.2f;

    // update cell values

    result.CellValues[0, 0] = "0";
    result.CellValues[1, 0] = "1";
    result.CellValues[2, 0] = "2";
    result.CellValues[3, 0] = "3";

    // create table cell template
    result.CellTemplate = new Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrEllipticalFieldTemplate();
    result.CellTemplate.FilledThreshold = 0.4f;

    // set table bounding box
    result.BoundingBox = new System.Drawing.RectangleF(6, 65, 20, 85);

    return result;
}

/// <summary>
/// Creates an OMR field template table for the second digit of day.
/// </summary>
/// <returns>An OMR field template table for the second digit of day.</returns>
private static Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrFieldTemplateTable CreateTemplateTableForSecondDigitInDay()
{
    // create template table
    Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrFieldTemplateTable result =
        new Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrFieldTemplateTable();

    // update table properties
    result.Name = "D2";
    result.ColumnCount = 1;
    result.RowCount = 10;
    result.Orientation = Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrTableOrientation.Vertical;
    result.DistanceBetweenColumns = 0.2f;
    result.DistanceBetweenRows = 0.2f;

    // update cell values

    result.CellValues[0, 0] = "0";
    result.CellValues[1, 0] = "1";
    result.CellValues[2, 0] = "2";
    result.CellValues[3, 0] = "3";
    result.CellValues[4, 0] = "4";
    result.CellValues[5, 0] = "5";
    result.CellValues[6, 0] = "6";
    result.CellValues[7, 0] = "7";
    result.CellValues[8, 0] = "8";
    result.CellValues[9, 0] = "9";

    // create table cell template
    result.CellTemplate = new Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrEllipticalFieldTemplate();
    result.CellTemplate.FilledThreshold = 0.4f;

    // set table bounding box
    result.BoundingBox = new System.Drawing.RectangleF(29, 65, 19, 216);

    return result;
}

/// <summary>
/// Creates an OMR field template table for the month.
/// </summary>
/// <returns>An OMR field template table for the month.</returns>
private static Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrFieldTemplateTable CreateTemplateTableForMonth()
{
    // create template table
    Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrFieldTemplateTable result =
        new Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrFieldTemplateTable();

    // update table properties
    result.Name = "Month";
    result.ColumnCount = 1;
    result.RowCount = 12;
    result.Orientation = Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrTableOrientation.Vertical;
    result.DistanceBetweenColumns = 0.2f;
    result.DistanceBetweenRows = 0.2f;

    // update cell values

    result.CellValues[0, 0] = "1";
    result.CellValues[1, 0] = "2";
    result.CellValues[2, 0] = "3";
    result.CellValues[3, 0] = "4";
    result.CellValues[4, 0] = "5";
    result.CellValues[5, 0] = "6";
    result.CellValues[6, 0] = "7";
    result.CellValues[7, 0] = "8";
    result.CellValues[8, 0] = "9";
    result.CellValues[9, 0] = "10";
    result.CellValues[9, 0] = "11";
    result.CellValues[9, 0] = "12";

    // create table cell template
    result.CellTemplate = new Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrEllipticalFieldTemplate();
    result.CellTemplate.FilledThreshold = 0.4f;

    // set table bounding box
    result.BoundingBox = new System.Drawing.RectangleF(59, 66, 15, 214);

    return result;
}

/// <summary>
/// Creates an OMR field template table for the first 2 digits of year.
/// </summary>
/// <returns>An OMR field template table for the first 2 digits of year.</returns>
private static Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrFieldTemplateTable CreateTemplateTableForFirstTwoDigitsInYear()
{
    // create template table
    Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrFieldTemplateTable result =
        new Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrFieldTemplateTable();

    // update table properties
    result.Name = "Y1";
    result.ColumnCount = 2;
    result.RowCount = 2;
    result.Orientation = Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrTableOrientation.Vertical;
    result.DistanceBetweenColumns = 0.2f;
    result.DistanceBetweenRows = 0.2f;

    // update cell values

    result.CellValues[0, 0] = "1";
    result.CellValues[0, 1] = "9";
    result.CellValues[1, 0] = "2";
    result.CellValues[1, 1] = "0";

    // create table cell template
    result.CellTemplate = new Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrEllipticalFieldTemplate();
    result.CellTemplate.FilledThreshold = 0.4f;

    // set table bounding box
    result.BoundingBox = new System.Drawing.RectangleF(154, 65, 42, 40);

    return result;
}

/// <summary>
/// Creates an OMR field template table for the last 2 digits of year.
/// </summary>
/// <returns>An OMR field template table for the last 2 digits of year.</returns>
private static Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrFieldTemplateTable CreateTemplateTableForLastTwoDigitsInYear()
{
    // create template table
    Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrFieldTemplateTable result =
        new Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrFieldTemplateTable();

    // update table properties
    result.Name = "Y2";
    result.ColumnCount = 2;
    result.RowCount = 10;
    result.Orientation = Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrTableOrientation.Vertical;
    result.DistanceBetweenColumns = 0.2f;
    result.DistanceBetweenRows = 0.2f;

    // update cell values

    result.CellValues[0, 0] = "0";
    result.CellValues[0, 1] = "0";
    result.CellValues[1, 0] = "1";
    result.CellValues[1, 1] = "1";
    result.CellValues[2, 0] = "2";
    result.CellValues[2, 1] = "2";
    result.CellValues[3, 0] = "3";
    result.CellValues[3, 1] = "3";
    result.CellValues[4, 0] = "4";
    result.CellValues[4, 1] = "4";
    result.CellValues[5, 0] = "5";
    result.CellValues[5, 1] = "5";
    result.CellValues[6, 0] = "6";
    result.CellValues[6, 1] = "6";
    result.CellValues[7, 0] = "7";
    result.CellValues[7, 1] = "7";
    result.CellValues[8, 0] = "8";
    result.CellValues[8, 1] = "8";
    result.CellValues[9, 0] = "9";
    result.CellValues[9, 1] = "9";

    // create table cell template
    result.CellTemplate = new Vintasoft.Imaging.FormsProcessing.FormRecognition.Omr.OmrEllipticalFieldTemplate();
    result.CellTemplate.FilledThreshold = 0.4f;

    // set table bounding box
    result.BoundingBox = new System.Drawing.RectangleF(199, 65, 41, 216);

    return result;
}

/// <summary>
/// Creates the form field template group.
/// </summary>
/// <param name="name">The group name.</param>
/// <param name="valueFormat">The group value format.</param>
/// <param name="items">The group items.</param>
private static Vintasoft.Imaging.FormsProcessing.FormRecognition.FormFieldTemplateGroup CreateTemplateGroup(
    string name,
    string valueFormat,
    params Vintasoft.Imaging.FormsProcessing.FormRecognition.FormFieldTemplate[] items)
{
    // create a form field template group
    Vintasoft.Imaging.FormsProcessing.FormRecognition.FormFieldTemplateGroup result =
        new Vintasoft.Imaging.FormsProcessing.FormRecognition.FormFieldTemplateGroup();
    // add item to the form field template group
    result.Items.AddRange(items);

    // set name of form field template group
    result.Name = name;
    // set value format of form field template group
    result.ValueFormat = valueFormat;

    return result;
}

Une fois le modèle de page de formulaire prêt, nous pouvons commencer la reconnaissance à partir de la page de formulaire remplie.

Voici l'image (résolution 100 dpi) d'un formulaire OMR rempli et non pivoté, contenant la date de naissance:


Voici l'image (résolution 200 dpi) d'un formulaire OMR rempli et non pivoté, contenant la date de naissance:


Voici l'image (résolution 300 dpi) d'un formulaire OMR rempli et non pivoté, contenant la date de naissance:


Voici l'image d'un formulaire OMR rempli et pivoté (20 degrés), contenant la date de naissance:


Voici l'image d'un formulaire OMR rempli et pivoté (150 degrés), contenant la date de naissance:



Voici le code C# montrant comment reconnaître le formulaire OMR contenant la date de naissance à partir de l'image de la page du formulaire rempli:

/// <summary>
/// Recognizes the birth date in filled OMR form.
/// </summary>
/// <param name="templateImagePath">A path to an image that represents a form template for filling the birth date.</param>
/// <param name="filledImagePath">A path to an image that represents filled form with the birth date.</param>
public static void RecognizeBirthDateInFilledOmrForm(string templateImagePath, string filledImagePath)
{
    // open an image that represents a form template for filling the birth date
    using (Vintasoft.Imaging.VintasoftImage templateImage = new Vintasoft.Imaging.VintasoftImage(templateImagePath))
    {
        // create a template manager
        Vintasoft.Imaging.FormsProcessing.FormRecognition.FormTemplateManager formTemplateManager =
            new Vintasoft.Imaging.FormsProcessing.FormRecognition.FormTemplateManager();
        // create a page template with birth date
        Vintasoft.Imaging.FormsProcessing.FormRecognition.FormPageTemplate formPageTemplate = CreatePageTemplateWithBirthDate();
        // add template image and page template to the template manager
        formTemplateManager.AddPageTemplate(templateImage, formPageTemplate);

        // open an image that represents filled form with the birth date
        using (Vintasoft.Imaging.VintasoftImage filledImage = new Vintasoft.Imaging.VintasoftImage(filledImagePath))
        {
            // recognize filled form with birth date
            RecognizeFilledFormInImage(formTemplateManager, filledImage);
        }
    }
}

/// <summary>
/// Recognizes filled form in an image.
/// </summary>
/// <param name="templateManager">The template manager that contains information about form template.</param>
/// <param name="image">An image that represents filled form.</param>
private static void RecognizeFilledFormInImage(
    Vintasoft.Imaging.FormsProcessing.FormRecognition.FormTemplateManager templateManager,
    Vintasoft.Imaging.VintasoftImage image)
{
    // create the template matching command
    Vintasoft.Imaging.FormsProcessing.TemplateMatching.TemplateMatchingCommand templateMatchingCommand =
        new Vintasoft.Imaging.FormsProcessing.TemplateMatching.TemplateMatchingCommand();
    // set the minimum confidence
    templateMatchingCommand.MinConfidence = 0.5f;
    // set template images
    templateMatchingCommand.TemplateImages = templateManager.TemplateImages;

    // create the form recognition manager
    Vintasoft.Imaging.FormsProcessing.FormRecognitionManager formRecognitionManager =
        new Vintasoft.Imaging.FormsProcessing.FormRecognitionManager(templateMatchingCommand, templateManager);

    // subscribe to the FormRecognitionResult.ImageRecognitionError event to output recognition errors
    formRecognitionManager.ImageRecognitionError += RecognitionManager_ImageRecognitionError;

    // recognize form in image
    Vintasoft.Imaging.FormsProcessing.FormRecognitionResult formRecognitionResult = formRecognitionManager.Recognize(image);

    // unsubscribe from FormRecognitionResult.ImageRecognitionError event
    formRecognitionManager.ImageRecognitionError -= RecognitionManager_ImageRecognitionError;

    // if recognition is failed
    if (formRecognitionResult == null)
        return;

    // get the result of image comparison
    Vintasoft.Imaging.FormsProcessing.TemplateMatching.ImageImprintCompareResult imageImprintCompareResult =
        formRecognitionResult.TemplateMatchingResult.ImageCompareResult;
    // if image comparison result is NOT reliable
    if (!imageImprintCompareResult.IsReliable)
    {
        // matching template is not found
        System.Console.WriteLine("Matching template is not found.");
    }
    // if image comparison result is reliable
    else
    {
        // get recognized form page
        Vintasoft.Imaging.FormsProcessing.FormRecognition.FormPage recognizedPage = formRecognitionResult.RecognizedPage;
        // write page info
        System.Console.WriteLine(string.Format(
            "Matching template: {0}; confidence: {1:F1}%.",
            recognizedPage.Name,
            imageImprintCompareResult.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 to the console
                System.Console.WriteLine(string.Format(
                    "  Name: {0}; value: {1}; confidence: {2:F1}%",
                    recognizedField.Name,
                    recognizedField.Value,
                    recognizedField.Confidence * 100));
            }
        }
    }
}

/// <summary>
/// Handles the ImageRecognitionError event of the FormRecognitionManager.
/// </summary>
private static void RecognitionManager_ImageRecognitionError(
    object sender,
    Vintasoft.Imaging.FormsProcessing.FormRecognitionErrorEventArgs e)
{
    // writes information about form recognition error to the console
    System.Console.WriteLine(e.Exception.Message);
}