发票 OCR 机器学习（逐步教程）

1. Accuracy and Reduced Errors

IronOCR utilizes advanced machine learning algorithms to recognize and extract text from invoices accurately. This minimizes the chances of human errors in data entry, ensuring that critical financial information is recorded correctly.

2. Time and Cost Savings

Automating invoice processing with IronOCR significantly reduces the time and resources required for manual data entry. This can lead to substantial cost savings by optimizing staff time and reducing the need for manual labor.

3. Improved Efficiency

IronOCR can process a large volume of invoices quickly and efficiently. It eliminates the need for employees to manually input data from each invoice, allowing them to focus on more strategic tasks.

4. Scalability

IronOCR is scalable and can handle a growing volume of invoices as your business expands. You don't need to worry about increased workloads and bounding boxes overwhelming your invoice document processing system.

5. Global Reach

IronOCR supports 125+ languages which allows businesses to process invoices from vendors and clients around the world. Regardless of the language in which an invoice is written, IronOCR can extract data accurately.

6. Multi-format Support

IronOCR can process invoices in various formats, including scanned images, image-based PDFs, and text-based PDFs. This versatility ensures that you can handle invoices from different sources and formats with ease.

7. Customization and Data Extraction

You can customize IronOCR to extract specific data fields from invoices, such as invoice numbers, dates, vendor details, and line item information. This level of customization allows you to tailor the solution to your specific business needs.

8. Compliance and Audit Trail

Automated invoice processing with IronOCR helps maintain accurate records and provides an audit trail. This is crucial for compliance with financial regulations and for simplifying the auditing process.

9. Reduced Invoice Processing Cycle

The streamlined and automated nature of IronOCR reduces the time it takes to process invoices, which, in turn, shortens the invoice processing cycle. This can lead to faster payments to vendors and improved relationships.

10. Enhanced Data Analysis

By having invoice data in a structured digital format, you can perform more in-depth data analysis. This can help identify trends, optimize spending, and make informed financial decisions.

Step 1: Create a New C#

Start by creating a new C# project or opening an existing project in your preferred development environment (e.g., Visual Studio or Visual Studio Code). I am using Visual Studio 2022 IDE and Console Application for this demonstration. You can use the same implementation in any project type such as ASP.NET Web APIs, ASP.NET MVC, ASP.NET Web Forms, or any .NET Framework.

Step 2: Install IronOCR via NuGet Package Manager

To use IronOCR in your project, you'll need to install the IronOCR NuGet package. Here's how to do it:

1. Open the NuGet Package Manager Console. In Visual Studio, you can find this under "Tools" > "NuGet Package Manager" > "Package Manager Console."

   

2. Run the following command to install the IronOCR package:

   Install-Package IronOcr

   

3. Wait for the package to be installed. Once completed, you can start using IronOCR in your project.

Step 3: Implement OCR in Your C#

Now, let's write the C# code to perform OCR on an invoice using IronOCR. We will use the following sample invoice for this example.

The following sample code will take the invoice image as input and will extract data from the invoice such as invoice number, purchase orders, etc.

// Define the path to the invoice image
string invoicePath = @"D:\Invoices\SampleInvoice.png";

// Create an instance of IronTesseract for OCR processing
IronTesseract ocr = new IronTesseract();

// Use 'using' to ensure proper disposal of OcrInput resources
using (OcrInput input = new OcrInput())
{
    // Add the invoice image to the OCR input
    input.AddImage(invoicePath);

    // Perform OCR on the input image and store result
    OcrResult result = ocr.Read(input);

    // Output the extracted text from the image to the console
    Console.WriteLine(result.Text);
}

// Define the path to the invoice image
string invoicePath = @"D:\Invoices\SampleInvoice.png";

// Create an instance of IronTesseract for OCR processing
IronTesseract ocr = new IronTesseract();

// Use 'using' to ensure proper disposal of OcrInput resources
using (OcrInput input = new OcrInput())
{
    // Add the invoice image to the OCR input
    input.AddImage(invoicePath);

    // Perform OCR on the input image and store result
    OcrResult result = ocr.Read(input);

    // Output the extracted text from the image to the console
    Console.WriteLine(result.Text);
}

' Define the path to the invoice image
Dim invoicePath As String = "D:\Invoices\SampleInvoice.png"

' Create an instance of IronTesseract for OCR processing
Dim ocr As New IronTesseract()

' Use 'using' to ensure proper disposal of OcrInput resources
Using input As New OcrInput()
	' Add the invoice image to the OCR input
	input.AddImage(invoicePath)

	' Perform OCR on the input image and store result
	Dim result As OcrResult = ocr.Read(input)

	' Output the extracted text from the image to the console
	Console.WriteLine(result.Text)
End Using

The above code is a concise C# example that uses IronOCR to perform OCR on a single invoice image (SampleInvoice.png) and then prints the extracted invoice data to the console. Make sure to replace the invoicePath variable with the path to your specific invoice image file.

Let's take multiple invoices input at once and extract their data. The following is the Invoices directory we are using as input.

The following sample code will perform text extraction from multiple invoices at once.

// Get all PNG files from the specified directory
string[] fileArray = Directory.GetFiles(@"D:\Invoices\", "*.png");

// Create an instance of IronTesseract for OCR processing
IronTesseract ocr = new IronTesseract();

// Use 'using' to ensure proper disposal of OcrInput resources
using (OcrInput input = new OcrInput())
{
    // Loop through each file and add it to the OCR input
    foreach (string file in fileArray)
    {
        input.AddImage(file);
    }

    // Perform OCR on all the added images and store the result
    OcrResult result = ocr.Read(input);

    // Output the extracted text from all images to the console
    Console.WriteLine(result.Text);
}

// Get all PNG files from the specified directory
string[] fileArray = Directory.GetFiles(@"D:\Invoices\", "*.png");

// Create an instance of IronTesseract for OCR processing
IronTesseract ocr = new IronTesseract();

// Use 'using' to ensure proper disposal of OcrInput resources
using (OcrInput input = new OcrInput())
{
    // Loop through each file and add it to the OCR input
    foreach (string file in fileArray)
    {
        input.AddImage(file);
    }

    // Perform OCR on all the added images and store the result
    OcrResult result = ocr.Read(input);

    // Output the extracted text from all images to the console
    Console.WriteLine(result.Text);
}

' Get all PNG files from the specified directory
Dim fileArray() As String = Directory.GetFiles("D:\Invoices\", "*.png")

' Create an instance of IronTesseract for OCR processing
Dim ocr As New IronTesseract()

' Use 'using' to ensure proper disposal of OcrInput resources
Using input As New OcrInput()
	' Loop through each file and add it to the OCR input
	For Each file As String In fileArray
		input.AddImage(file)
	Next file

	' Perform OCR on all the added images and store the result
	Dim result As OcrResult = ocr.Read(input)

	' Output the extracted text from all images to the console
	Console.WriteLine(result.Text)
End Using

The above code will get all the PNG images from the folder, extract data, and then print the extracted data of all the invoices in the folder on the console.

Save Extracted Data as a Searchable PDF Invoice

The following code will read all the images from the folder, perform data extraction, and save them as a single searchable PDF invoice.

// Get all PNG files from the specified directory
string[] fileArray = Directory.GetFiles(@"D:\Invoices\", "*.png");

// Create an instance of IronTesseract for OCR processing
IronTesseract ocr = new IronTesseract();

// Use 'using' to ensure proper disposal of OcrInput resources
using (OcrInput input = new OcrInput())
{
    // Loop through each file and add it to the OCR input
    foreach (string file in fileArray)
    {
        input.AddImage(file);
    }

    // Perform OCR on all the added images and store the result
    OcrResult result = ocr.Read(input);

    // Save the result as a searchable PDF
    result.SaveAsSearchablePdf(@"D:\Invoices\Searchable.pdf");
}

// Get all PNG files from the specified directory
string[] fileArray = Directory.GetFiles(@"D:\Invoices\", "*.png");

// Create an instance of IronTesseract for OCR processing
IronTesseract ocr = new IronTesseract();

// Use 'using' to ensure proper disposal of OcrInput resources
using (OcrInput input = new OcrInput())
{
    // Loop through each file and add it to the OCR input
    foreach (string file in fileArray)
    {
        input.AddImage(file);
    }

    // Perform OCR on all the added images and store the result
    OcrResult result = ocr.Read(input);

    // Save the result as a searchable PDF
    result.SaveAsSearchablePdf(@"D:\Invoices\Searchable.pdf");
}

' Get all PNG files from the specified directory
Dim fileArray() As String = Directory.GetFiles("D:\Invoices\", "*.png")

' Create an instance of IronTesseract for OCR processing
Dim ocr As New IronTesseract()

' Use 'using' to ensure proper disposal of OcrInput resources
Using input As New OcrInput()
	' Loop through each file and add it to the OCR input
	For Each file As String In fileArray
		input.AddImage(file)
	Next file

	' Perform OCR on all the added images and store the result
	Dim result As OcrResult = ocr.Read(input)

	' Save the result as a searchable PDF
	result.SaveAsSearchablePdf("D:\Invoices\Searchable.pdf")
End Using

The code is almost similar in all examples; we are just making slight changes for demonstrating different use cases. The output PDF is shown below:

In this way, IronPDF provides the easiest way to automate invoice processing and document processing.

Extract Invoice Data from PDF Invoices

To extract data from PDF invoices using IronOCR, you can follow a similar approach as in the previous code example. IronOCR is capable of handling both image-based and text-based PDFs. Here's a brief example of how to extract data from a PDF invoice:

// Get all PDF files from the specified directory
string[] fileArray = Directory.GetFiles(@"D:\Invoices\", "*.pdf");

// Create an instance of IronTesseract for OCR processing
IronTesseract ocr = new IronTesseract();

// Use 'using' to ensure proper disposal of OcrInput resources
using (OcrInput input = new OcrInput())
{
    // Loop through each file and add it to the OCR input
    foreach (string file in fileArray)
    {
        input.AddPdf(file);
    }

    // Perform OCR on all the added PDFs and store the result
    OcrResult result = ocr.Read(input);

    // Output the extracted text from all PDFs to the console
    Console.WriteLine(result.Text);
}

// Get all PDF files from the specified directory
string[] fileArray = Directory.GetFiles(@"D:\Invoices\", "*.pdf");

// Create an instance of IronTesseract for OCR processing
IronTesseract ocr = new IronTesseract();

// Use 'using' to ensure proper disposal of OcrInput resources
using (OcrInput input = new OcrInput())
{
    // Loop through each file and add it to the OCR input
    foreach (string file in fileArray)
    {
        input.AddPdf(file);
    }

    // Perform OCR on all the added PDFs and store the result
    OcrResult result = ocr.Read(input);

    // Output the extracted text from all PDFs to the console
    Console.WriteLine(result.Text);
}

' Get all PDF files from the specified directory
Dim fileArray() As String = Directory.GetFiles("D:\Invoices\", "*.pdf")

' Create an instance of IronTesseract for OCR processing
Dim ocr As New IronTesseract()

' Use 'using' to ensure proper disposal of OcrInput resources
Using input As New OcrInput()
	' Loop through each file and add it to the OCR input
	For Each file As String In fileArray
		input.AddPdf(file)
	Next file

	' Perform OCR on all the added PDFs and store the result
	Dim result As OcrResult = ocr.Read(input)

	' Output the extracted text from all PDFs to the console
	Console.WriteLine(result.Text)
End Using

The above code efficiently batch processes multiple PDF invoices located in a directory (@"D:\Invoices\") using IronOCR. It retrieves the file paths, adds each PDF for OCR processing, combines the extracted text, and prints the result to the console. This approach streamlines invoice data extraction for organizations dealing with a substantial number of invoices, enhancing efficiency and reducing manual effort.