IronOCR 和 Nanonets OCR 之间的比较

IronOCR for .NET is a C# library that enables users to scan, search, and read images and PDFs. It takes an image or PDF file as input and uses the latest Tesseract 5 custom-built .NET OCR engine to output text, structured data, or searchable PDF documents. Tesseract is available in 125+ languages, and IronOCR offers cross-platform support in .NET Core, Standard, from 2.0 up to 7.

IronOCR is a user-friendly API that allows C# developers to automatically convert images to text using the IronTesseract class. The library prioritizes speed, accuracy, and ease of use.

Another powerful feature of IronOCR is its ability to scan barcodes and QR codes from all image files and read their text. Additional important features of IronOCR are listed below.

Features

• International Languages: 125+ and custom languages support.
• Text and Barcode Reading: Read text and numbers from multiple languages at once.
• Specialist Documents: Read text from specialty documents such as receipts, checks, and invoices.
• Read from Many Formats: Read from images (PNG, JPG, GIF, TIFF, BMP), System.Drawing Objects, streams, PDF documents, and more.
• Preprocessing Features: Includes preprocessing features such as the Filter Wizard, image correction, orientation correction, and color correction.
• Simple Data Output: Outputs in .NET Text Strings, Barcode, QR, and Image format.

Now, let's have a look at Nanonets OCR API.

2.1. Using Visual Studio NuGet Package Manager

NuGet is the package manager for downloading and installing dependencies in your project. Its packages contain compiled code and (DLLs) and the manifest file. Access it using the following method:

• Click on the tools tab.
• Extend the NuGet Package Manager option.

• Click Manage NuGet Packages for Solutions.

  

Alternatively:

• Right-click Solution Explorer.

• Click Manage NuGet Packages.

  

Now, the NuGet Package Manager window will open. Browse for IronOCR and click Install.

2.2. Download from NuGet Website

IronOCR can also be downloaded directly from the NuGet official website. Follow these steps:

1. Visit the NuGet website.
2. Click the "download package" option on the right-hand side of the page.
3. Open the downloaded package to start installing.
4. Finally, reload the solution and it's done.

2.3. Download using the IronOCR Webpage

Visit the Iron Software website and navigate to the IronOCR for .NET webpage. Scroll to the bottom and click Download DLL or Download Windows installer.

A zip file will be downloaded. Extract the project file or run the Windows installer. Follow the steps below to add it to your project.

1. Right-click the dependencies of the project in Visual Studio from the solution explorer.
2. Select the option Add Project Reference.
3. Browse to the downloaded DLL file location.
4. Finally, click OK to add a project reference.

2.4. Using Command prompt in Visual Studio

1. Navigate to the Tools tab in Visual Studio.
2. Extend the NuGet Package Manager option.
3. Select Package Manager Console and type the following command:

Install-Package IronOcr

This will automatically download and install IronOCR in your project.

Now, we are ready to use IronOCR in our project.

2.5. Adding the Necessary IronOCR Namespaces

There is only one namespace required, which needs to be added on top of the source code file where we need to access IronOCR's functions.

using IronOcr;

using IronOcr;

Imports IronOcr

Now, let's install Nanonets OCR API.

3.1. Adding RestSharp Namespace

RestSharp is a simple Rest and HTTP client library for .NET. It is used to send and receive API requests and handle responses. This library is needed to execute Nanonets API code since it is also a REST API.

To install RestSharp, open the NuGet Package Manager for your solution, browse for RestSharp, and install it. Alternatively, you can open the Package Manager Console and type the following command:

Install-Package RestSharp

Now, everything is set up and ready to use.

4.1. Using IronOCR

var Ocr = new IronTesseract();
using (var Input = new OcrInput()){
  Input.AddImage("test-files/employmentapp.png");
  var Result = Ocr.Read(Input);
  Console.WriteLine(Result.Text);
}

var Ocr = new IronTesseract();
using (var Input = new OcrInput()){
  Input.AddImage("test-files/employmentapp.png");
  var Result = Ocr.Read(Input);
  Console.WriteLine(Result.Text);
}

Dim Ocr = New IronTesseract()
Using Input = New OcrInput()
  Input.AddImage("test-files/employmentapp.png")
  Dim Result = Ocr.Read(Input)
  Console.WriteLine(Result.Text)
End Using

4.2. Using Nanonets OCR

Nanonets also provides the facility to extract text from images. To do this, an API call is made with the authentication key, and then the image is uploaded to the Nanonets server. The fast OCR tool will then return the extracted text as a response to the application. Here is an example of the code:

var client = new RestClient("https://app.nanonets.com/api/v2/OCR/FullText");
client.Timeout = -1;
var request = new RestRequest(Method.POST);
request.AddHeader("Authorization", "Basic " + Convert.ToBase64String(Encoding.Default.GetBytes("REPLACE_YOUR_API_KEY:")));
request.AddFile("file", "FILE_PATH");
RestResponse response = client.Execute(request);
Console.WriteLine(response.Content);

var client = new RestClient("https://app.nanonets.com/api/v2/OCR/FullText");
client.Timeout = -1;
var request = new RestRequest(Method.POST);
request.AddHeader("Authorization", "Basic " + Convert.ToBase64String(Encoding.Default.GetBytes("REPLACE_YOUR_API_KEY:")));
request.AddFile("file", "FILE_PATH");
RestResponse response = client.Execute(request);
Console.WriteLine(response.Content);

Dim client = New RestClient("https://app.nanonets.com/api/v2/OCR/FullText")
client.Timeout = -1
Dim request = New RestRequest(Method.POST)
request.AddHeader("Authorization", "Basic " & Convert.ToBase64String(Encoding.Default.GetBytes("REPLACE_YOUR_API_KEY:")))
request.AddFile("file", "FILE_PATH")
Dim response As RestResponse = client.Execute(request)
Console.WriteLine(response.Content)

The output is not perfect. The image contained structured data, only some of which is properly fetched. With another simple text image, the output was fine. Note that the model can be trained for more accurate results.

5.1. Using IronOCR

var Ocr = new IronTesseract();
Ocr.Configuration.ReadBarCodes = true;
using (var input = new OcrInput()) {    
    input.AddImage("test-files/Barcode.png");    
    var Result = Ocr.Read(input);    
    foreach (var Barcode in Result.Barcodes){
        Console.WriteLine(Barcode.Value);
    }
}

var Ocr = new IronTesseract();
Ocr.Configuration.ReadBarCodes = true;
using (var input = new OcrInput()) {    
    input.AddImage("test-files/Barcode.png");    
    var Result = Ocr.Read(input);    
    foreach (var Barcode in Result.Barcodes){
        Console.WriteLine(Barcode.Value);
    }
}

Dim Ocr = New IronTesseract()
Ocr.Configuration.ReadBarCodes = True
Using input = New OcrInput()
	input.AddImage("test-files/Barcode.png")
	Dim Result = Ocr.Read(input)
	For Each Barcode In Result.Barcodes
		Console.WriteLine(Barcode.Value)
	Next Barcode
End Using

5.2. Using Nanonets OCR

Nanonets OCR API provides the facility to detect QR codes. However, this functionality is only available in the Enterprise plan, and you will need to contact sales to use it. Additionally, Nanonets allows you to detect specific parts of documents or receipts. It also provides other features such as accounts payable, invoice processing, and accounting automation.

6.1. Using IronOCR

Reading PDF files is just as simple as reading image files with IronOCR. The only change required is to use the AddPdf method instead of AddImage in the code for reading images. The code is as follows:

var Ocr = new IronTesseract();
using (var Input = new OcrInput()) {
    Input.AddPdf("test-files/example.pdf");
    var Result = Ocr.Read(Input);
    Console.WriteLine(Result.Text);
}

var Ocr = new IronTesseract();
using (var Input = new OcrInput()) {
    Input.AddPdf("test-files/example.pdf");
    var Result = Ocr.Read(Input);
    Console.WriteLine(Result.Text);
}

Dim Ocr = New IronTesseract()
Using Input = New OcrInput()
	Input.AddPdf("test-files/example.pdf")
	Dim Result = Ocr.Read(Input)
	Console.WriteLine(Result.Text)
End Using

The extracted text is in the same format as the PDF file.

6.2. Using Nanonets OCR

Reading data from PDF files is also available in the Nanonets OCR API. The code is almost identical to the image text detection code, except for the URL used in the request. Let's take a look at the code:

var client = new RestClient("https://app.nanonets.com/api/v2/OCR/Model/{{model_id}}/LabelFile/?async=false");
var request = new RestRequest(Method.POST);
request.AddHeader("Authorization", "Basic " + Convert.ToBase64String(Encoding.Default.GetBytes("REPLACE_YOUR_API_KEY:")));
request.AddHeader("Accept", "Multipart/form-data");
request.AddFile("file", "test-files/example.pdf");
RestResponse response = client.Execute(request);
Console.WriteLine(response.Content);

var client = new RestClient("https://app.nanonets.com/api/v2/OCR/Model/{{model_id}}/LabelFile/?async=false");
var request = new RestRequest(Method.POST);
request.AddHeader("Authorization", "Basic " + Convert.ToBase64String(Encoding.Default.GetBytes("REPLACE_YOUR_API_KEY:")));
request.AddHeader("Accept", "Multipart/form-data");
request.AddFile("file", "test-files/example.pdf");
RestResponse response = client.Execute(request);
Console.WriteLine(response.Content);

Dim client = New RestClient("https://app.nanonets.com/api/v2/OCR/Model/{{model_id}}/LabelFile/?async=false")
Dim request = New RestRequest(Method.POST)
request.AddHeader("Authorization", "Basic " & Convert.ToBase64String(Encoding.Default.GetBytes("REPLACE_YOUR_API_KEY:")))
request.AddHeader("Accept", "Multipart/form-data")
request.AddFile("file", "test-files/example.pdf")
Dim response As RestResponse = client.Execute(request)
Console.WriteLine(response.Content)

In the above code, replace the model_id with your OCR model ID. Also, replace the API key with your own API key. Then, replace the PDF file path with the path to your own file.

The output is similar to IronOCR, but with extra spaces and new lines included in the output of Nanonets OCR.