How to Read Table in Documents

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Let’s talk about reading tables in documents. Extracting data from tables using plain Tesseract can be challenging, as the text often resides in cells and is sparsely scattered across the document. However, our library is equipped with a machine learning model that has been trained and fine-tuned for detecting and extracting table data accurately.

For simple tables, you can rely on straightforward table detection, while for more complex structures, our exclusive ReadDocumentAdvanced method provides robust results, effectively parsing the table and delivering data.

Quickstart: Extract Complex Table Cells in One Call

Get up and running in minutes—this example shows how a single IronOCR call using ReadDocumentAdvanced gives you detailed table cell data out of a complex document. It demonstrates ease of use by loading a PDF, applying advanced table detection, and returning a list of cell information directly.

Nuget IconGet started making PDFs with NuGet now:

  1. Install IronOCR with NuGet Package Manager

    PM > Install-Package IronOcr

  2. Copy and run this code snippet.

    var cells = new IronTesseract().ReadDocumentAdvanced(new OcrInput().LoadPdf("invoiceTable.pdf")).Tables.First().CellInfos;
  3. Deploy to test on your live environment

    Start using IronOCR in your project today with a free trial
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The following steps guide you in getting started with reading tables using IronOCR:


Simple Table Example

Setting the ReadDataTables property to true enables table detection using Tesseract. I created a simple table PDF to test this feature, which you can download here: 'simple-table.pdf'. Simple tables without merged cells can be detected using this method. For more complex tables, please refer to the method described below.

:path=/static-assets/ocr/content-code-examples/how-to/read-table-in-document-with-tesseract.cs
using IronOcr;
using System;
using System.Data;

// Instantiate OCR engine
var ocr = new IronTesseract();

// Enable table detection
ocr.Configuration.ReadDataTables = true;

using var input = new OcrPdfInput("simple-table.pdf");
var result = ocr.Read(input);

// Retrieve the data
var table = result.Tables[0].DataTable;

// Print out the table data
foreach (DataRow row in table.Rows)
{
    foreach (var item in row.ItemArray)
    {
        Console.Write(item + "\t");
    }
    Console.WriteLine();
}
Imports Microsoft.VisualBasic
Imports IronOcr
Imports System
Imports System.Data

' Instantiate OCR engine
Private ocr = New IronTesseract()

' Enable table detection
ocr.Configuration.ReadDataTables = True

Dim input = New OcrPdfInput("simple-table.pdf")
Dim result = ocr.Read(input)

' Retrieve the data
Dim table = result.Tables(0).DataTable

' Print out the table data
For Each row As DataRow In table.Rows
	For Each item In row.ItemArray
		Console.Write(item & vbTab)
	Next item
	Console.WriteLine()
Next row
$vbLabelText   $csharpLabel

Reading Invoices Example

One of the more common complex tables found in business settings are invoices. Invoices themselves are complex tables with rows and columns of data. With IronOCR, we utilize the ReadDocumentAdvanced method to handle them beautifully. The process involves scanning the document, identifying the table structure, and extracting the data. In this example, we’ll use the 'invoiceTable.pdf' file to showcase how IronOCR retrieves all information from the invoice.

The ReadDocumentAdvanced method requires the IronOcr.Extensions.AdvancedScan package to be installed alongside the base IronOCR package.

Por favor nota Using advanced scan on .NET Framework requires the project to run on x64 architecture. Navigate to the project configuration and uncheck the "Prefer 32-bit" option to achieve this. Learn more in the following troubleshooting guide: "Advanced Scan on .NET Framework."

:path=/static-assets/ocr/content-code-examples/how-to/read-table-in-document-with-ml.cs
using IronOcr;
using System.Linq;

// Instantiate OCR engine
var ocr = new IronTesseract();

using var input = new OcrInput();
input.LoadPdf("invoiceTable.pdf");

// Perform OCR
var result = ocr.ReadDocumentAdvanced(input);

var cellList = result.Tables.First().CellInfos;
IRON VB CONVERTER ERROR developers@ironsoftware.com
$vbLabelText   $csharpLabel

This method separates the text data of the document into two categories: one enclosed by borders and another without borders. For the bordered content, the library further divides it into subsections based on the table's structure. The results are shown below. It is important to note that, since this method focuses on information enclosed by borders, any merged cells spanning multiple rows will be treated as a single cell.

Result

Read Table in Document

Helper Class

In the current implementation, the extracted cells are not yet organized properly. However, each cell contains valuable information such as X and Y coordinates, dimensions, and more. Using this data, we can create a helper class for various purposes. Below are some basic helper methods:

using System;
using System.Collections.Generic;
using System.Linq;

// A helper class to process table data by sorting cells based on coordinates
public static class TableProcessor
{
    // Method to organize cells by their coordinates (Y top to bottom, X left to right)
    public static List<CellInfo> OrganizeCellsByCoordinates(List<CellInfo> cells)
    {
        // Sort cells by Y (top to bottom), then by X (left to right)
        var sortedCells = cells
            .OrderBy(cell => cell.CellRect.Y)
            .ThenBy(cell => cell.CellRect.X)
            .ToList();

        return sortedCells;
    }

    // Example method demonstrating how to process multiple tables
    public static void ProcessTables(Tables tables)
    {
        foreach (var table in tables)
        {
            var sortedCells = OrganizeCellsByCoordinates(table.CellInfos);

            Console.WriteLine("Organized Table Cells:");

            // Initialize previous Y coordinate
            int previousY = sortedCells.Any() ? sortedCells.First().CellRect.Y : 0;

            foreach (var cell in sortedCells)
            {
                // Print a new line if the Y-coordinate changes, indicating a new row
                if (Math.Abs(cell.CellRect.Y - previousY) > cell.CellRect.Height * 0.8)
                {
                    Console.WriteLine();  // Start a new row
                    previousY = cell.CellRect.Y;
                }

                // Print the cell text followed by a tab
                Console.Write($"{cell.CellText}\t");
            }

            Console.WriteLine("\n--- End of Table ---");  // End of a table
        }
    }

    // Method to extract a specific row by the given index
    public static List<CellInfo> ExtractRowByIndex(TableInfo table, int rowIndex)
    {
        if (table == null || table.CellInfos == null || !table.CellInfos.Any())
        {
            throw new ArgumentException("Table is empty or invalid.");
        }

        var sortedCells = OrganizeCellsByCoordinates(table.CellInfos);
        List<List<CellInfo>> rows = new List<List<CellInfo>>();

        // Group cells into rows based on Y coordinates
        int previousY = sortedCells.First().CellRect.Y;
        List<CellInfo> currentRow = new List<CellInfo>();

        foreach (var cell in sortedCells)
        {
            if (Math.Abs(cell.CellRect.Y - previousY) > cell.CellRect.Height * 0.8)
            {
                // Store the completed row and start a new one
                rows.Add(new List<CellInfo>(currentRow));
                currentRow.Clear();

                previousY = cell.CellRect.Y;
            }

            currentRow.Add(cell);
        }

        // Add the last row if it wasn't added yet
        if (currentRow.Any())
        {
            rows.Add(currentRow);
        }

        // Retrieve the specified row
        if (rowIndex < 0 || rowIndex >= rows.Count)
        {
            throw new IndexOutOfRangeException($"Row index {rowIndex} is out of range.");
        }

        return rows[rowIndex];
    }
}
using System;
using System.Collections.Generic;
using System.Linq;

// A helper class to process table data by sorting cells based on coordinates
public static class TableProcessor
{
    // Method to organize cells by their coordinates (Y top to bottom, X left to right)
    public static List<CellInfo> OrganizeCellsByCoordinates(List<CellInfo> cells)
    {
        // Sort cells by Y (top to bottom), then by X (left to right)
        var sortedCells = cells
            .OrderBy(cell => cell.CellRect.Y)
            .ThenBy(cell => cell.CellRect.X)
            .ToList();

        return sortedCells;
    }

    // Example method demonstrating how to process multiple tables
    public static void ProcessTables(Tables tables)
    {
        foreach (var table in tables)
        {
            var sortedCells = OrganizeCellsByCoordinates(table.CellInfos);

            Console.WriteLine("Organized Table Cells:");

            // Initialize previous Y coordinate
            int previousY = sortedCells.Any() ? sortedCells.First().CellRect.Y : 0;

            foreach (var cell in sortedCells)
            {
                // Print a new line if the Y-coordinate changes, indicating a new row
                if (Math.Abs(cell.CellRect.Y - previousY) > cell.CellRect.Height * 0.8)
                {
                    Console.WriteLine();  // Start a new row
                    previousY = cell.CellRect.Y;
                }

                // Print the cell text followed by a tab
                Console.Write($"{cell.CellText}\t");
            }

            Console.WriteLine("\n--- End of Table ---");  // End of a table
        }
    }

    // Method to extract a specific row by the given index
    public static List<CellInfo> ExtractRowByIndex(TableInfo table, int rowIndex)
    {
        if (table == null || table.CellInfos == null || !table.CellInfos.Any())
        {
            throw new ArgumentException("Table is empty or invalid.");
        }

        var sortedCells = OrganizeCellsByCoordinates(table.CellInfos);
        List<List<CellInfo>> rows = new List<List<CellInfo>>();

        // Group cells into rows based on Y coordinates
        int previousY = sortedCells.First().CellRect.Y;
        List<CellInfo> currentRow = new List<CellInfo>();

        foreach (var cell in sortedCells)
        {
            if (Math.Abs(cell.CellRect.Y - previousY) > cell.CellRect.Height * 0.8)
            {
                // Store the completed row and start a new one
                rows.Add(new List<CellInfo>(currentRow));
                currentRow.Clear();

                previousY = cell.CellRect.Y;
            }

            currentRow.Add(cell);
        }

        // Add the last row if it wasn't added yet
        if (currentRow.Any())
        {
            rows.Add(currentRow);
        }

        // Retrieve the specified row
        if (rowIndex < 0 || rowIndex >= rows.Count)
        {
            throw new IndexOutOfRangeException($"Row index {rowIndex} is out of range.");
        }

        return rows[rowIndex];
    }
}
Imports Microsoft.VisualBasic
Imports System
Imports System.Collections.Generic
Imports System.Linq

' A helper class to process table data by sorting cells based on coordinates
Public Module TableProcessor
	' Method to organize cells by their coordinates (Y top to bottom, X left to right)
	Public Function OrganizeCellsByCoordinates(ByVal cells As List(Of CellInfo)) As List(Of CellInfo)
		' Sort cells by Y (top to bottom), then by X (left to right)
		Dim sortedCells = cells.OrderBy(Function(cell) cell.CellRect.Y).ThenBy(Function(cell) cell.CellRect.X).ToList()

		Return sortedCells
	End Function

	' Example method demonstrating how to process multiple tables
	Public Sub ProcessTables(ByVal tables As Tables)
		For Each table In tables
			Dim sortedCells = OrganizeCellsByCoordinates(table.CellInfos)

			Console.WriteLine("Organized Table Cells:")

			' Initialize previous Y coordinate
			Dim previousY As Integer = If(sortedCells.Any(), sortedCells.First().CellRect.Y, 0)

			For Each cell In sortedCells
				' Print a new line if the Y-coordinate changes, indicating a new row
				If Math.Abs(cell.CellRect.Y - previousY) > cell.CellRect.Height * 0.8 Then
					Console.WriteLine() ' Start a new row
					previousY = cell.CellRect.Y
				End If

				' Print the cell text followed by a tab
				Console.Write($"{cell.CellText}" & vbTab)
			Next cell

			Console.WriteLine(vbLf & "--- End of Table ---") ' End of a table
		Next table
	End Sub

	' Method to extract a specific row by the given index
	Public Function ExtractRowByIndex(ByVal table As TableInfo, ByVal rowIndex As Integer) As List(Of CellInfo)
		If table Is Nothing OrElse table.CellInfos Is Nothing OrElse Not table.CellInfos.Any() Then
			Throw New ArgumentException("Table is empty or invalid.")
		End If

		Dim sortedCells = OrganizeCellsByCoordinates(table.CellInfos)
		Dim rows As New List(Of List(Of CellInfo))()

		' Group cells into rows based on Y coordinates
		Dim previousY As Integer = sortedCells.First().CellRect.Y
		Dim currentRow As New List(Of CellInfo)()

		For Each cell In sortedCells
			If Math.Abs(cell.CellRect.Y - previousY) > cell.CellRect.Height * 0.8 Then
				' Store the completed row and start a new one
				rows.Add(New List(Of CellInfo)(currentRow))
				currentRow.Clear()

				previousY = cell.CellRect.Y
			End If

			currentRow.Add(cell)
		Next cell

		' Add the last row if it wasn't added yet
		If currentRow.Any() Then
			rows.Add(currentRow)
		End If

		' Retrieve the specified row
		If rowIndex < 0 OrElse rowIndex >= rows.Count Then
			Throw New IndexOutOfRangeException($"Row index {rowIndex} is out of range.")
		End If

		Return rows(rowIndex)
	End Function
End Module
$vbLabelText   $csharpLabel

Preguntas Frecuentes

¿Cómo puedo mejorar la extracción de datos de tablas en documentos usando C#?

Puede mejorar la extracción de datos de tablas en documentos usando C# al utilizar el modelo de aprendizaje automático de IronOCR, que está específicamente entrenado para detectar y extraer datos complejos de tablas con precisión. Este enfoque es más efectivo que usar herramientas estándar de OCR como Tesseract.

¿Cuál es el propósito del método `ReadDocumentAdvanced` en IronOCR?

El método `ReadDocumentAdvanced` en IronOCR está diseñado para manejar tablas complejas proporcionando resultados robustos a través de un análisis efectivo y extracción de datos. Es particularmente útil para tratar con tablas de estructuras intrincadas.

¿Cómo puedo comenzar con la extracción de tablas usando IronOCR?

Para comenzar a extraer tablas usando IronOCR, descargue la biblioteca de C#, prepare su documento, habilite la detección de tablas configurando la propiedad ReadDataTables y utilice el método ReadDocumentAdvanced para tablas complejas.

¿Qué paquete adicional se requiere para la extracción avanzada de tablas en IronOCR?

La extracción avanzada de tablas en IronOCR requiere el paquete `IronOcr.Extensions.AdvancedScan`, que es específico para Windows, para manejar de manera efectiva las estructuras complejas de tablas.

¿Cómo puedo organizar los datos extraídos de las tablas usando IronOCR?

IronOCR proporciona métodos auxiliares para organizar los datos extraídos de las tablas por coordenadas, permitiéndole procesar múltiples tablas y extraer filas específicas por índice para una mejor gestión de los datos.

¿Qué metadatos se incluyen en las celdas de tabla extraídas usando IronOCR?

Las celdas de tabla extraídas usando IronOCR incluyen metadatos como coordenadas X e Y, dimensiones de la celda y el contenido de texto dentro de cada celda, permitiendo un análisis y organización de datos detallados.

¿Cómo puedo asegurar la compatibilidad con .NET Framework al usar IronOCR para la extracción de tablas?

Para asegurar la compatibilidad con .NET Framework, asegúrese de que su proyecto se ejecute en la arquitectura x64 y desmarque la opción 'Preferir 32 bits' en la configuración del proyecto al usar IronOCR para la extracción de tablas.

Curtis Chau
Escritor Técnico

Curtis Chau tiene una licenciatura en Ciencias de la Computación (Carleton University) y se especializa en el desarrollo front-end con experiencia en Node.js, TypeScript, JavaScript y React. Apasionado por crear interfaces de usuario intuitivas y estéticamente agradables, disfruta trabajando con frameworks modernos y creando manuales bien ...

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Revisado por
Jeff Fritz
Jeffrey T. Fritz
Gerente Principal de Programas - Equipo de la Comunidad .NET
Jeff también es Gerente Principal de Programas para los equipos de .NET y Visual Studio. Es el productor ejecutivo de la serie de conferencias virtuales .NET Conf y anfitrión de 'Fritz and Friends', una transmisión en vivo para desarrolladores que se emite dos veces a la semana donde habla sobre tecnología y escribe código junto con la audiencia. Jeff escribe talleres, presentaciones, y planifica contenido para los eventos de desarrolladores más importantes de Microsoft, incluyendo Microsoft Build, Microsoft Ignite, .NET Conf y la Cumbre de Microsoft MVP.
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