发票 OCR 开源比较：寻找最佳工具

Capabilities and Features of Tesseract OCR in C#

Integration in .NET Applications: Integrating Tesseract OCR into C# projects involves using the Tesseract .NET SDK or wrapper. This provides an efficient way to incorporate OCR functionalities while working within the familiar .NET environment.

Text Recognition: Tesseract OCR excels at recognizing and extracting text from various image formats. It's adept at processing a range of document types, from scanned documents and PDF files to images captured in challenging lighting conditions or angles.

Support for Multiple Languages: Tesseract supports over 100 languages, making it incredibly versatile for global applications that process text from diverse linguistic sources.

Customization and Training: Tesseract allows developers to train the engine with new fonts and languages, offering tailored OCR solutions that suit specific business needs or document types.

Advantages of Emgu CV

Cross-Platform: Emgu CV functions on any platform that supports .NET, including iOS, Android, Mac OS, Linux, and Windows.

Cross-Language: Besides C#, Emgu CV is accessible in several languages, including VB.NET, C++, and IronPython, with extensive example code and robust documentation support.

Features of At9T

User-Friendly Interface: The interface is designed for ease of use, allowing even those with no prior experience to navigate it easily.

Multiple Language Support: Supports various languages, including English, Dutch, Japanese, Korean, and more.

Batch Processing: Capable of processing multiple files simultaneously, saving time when extracting data from numerous documents.

Key Features of IronOCR

Input Flexibility: Handles various formats like images (JPG, PNG, BMP), multi-page/frame files (TIFF, GIF), System.Drawing objects, streams, and PDFs with optimized DPI.

Advanced Filters: Offers filters for image correction (sharpening, resolution enhancement, etc.) and color correction to ensure optimal quality before OCR.

Region Selection: Allows for specific document regions to be selected for OCR using CropRectangle.

Data Output: Provides data output as .NET text strings, barcodes, QR data, and images.

Structured Data: Outputs structured data by pages, blocks, paragraphs, lines, words, and characters.

Document Export: Enables export as searchable PDFs, HTML, or images.

Text Highlighting & Saving: Features to highlight and save text at various granularities.

Languages & Frameworks: Supports C#, VB.NET, F#, and is compatible with various .NET frameworks.

Operating Systems: Compatible with Windows, macOS, Linux, Docker, Azure, and AWS.

IDE Support: Fully supported on Microsoft Visual Studio and JetBrains ReSharper & Rider.

Example

Below is an example code snippet to extract data from an invoice using IronOCR:

// Create an instance of IronTesseract
var tesseract = new IronTesseract();

// Create an OcrInput object
using (var input = new OcrInput("sample_invoice.png")) // Pass the image path directly to constructor
{
    // Read and store OcrResults object
    var result = tesseract.Read(input);

    // Get all text from the OCR result
    string allText = result.Text;

    // Print the extracted text to the console
    Console.WriteLine(allText);
}

// Create an instance of IronTesseract
var tesseract = new IronTesseract();

// Create an OcrInput object
using (var input = new OcrInput("sample_invoice.png")) // Pass the image path directly to constructor
{
    // Read and store OcrResults object
    var result = tesseract.Read(input);

    // Get all text from the OCR result
    string allText = result.Text;

    // Print the extracted text to the console
    Console.WriteLine(allText);
}

' Create an instance of IronTesseract
Dim tesseract = New IronTesseract()

' Create an OcrInput object
Using input = New OcrInput("sample_invoice.png") ' Pass the image path directly to constructor
	' Read and store OcrResults object
	Dim result = tesseract.Read(input)

	' Get all text from the OCR result
	Dim allText As String = result.Text

	' Print the extracted text to the console
	Console.WriteLine(allText)
End Using

The output data extracted from the invoice image is shown below:

Subsequent data analysis can convert this recognized data into formats such as CSVs for easier handling.