C#: Use OCR SDK Library to Get Image and Document Text

RasterEdge provides users with the most standard and comprehensive Optical Character Recognition SDK that is fully developed, highly accurate and easy to work within C#.NET, VB.NET, ASP.NET web and .NET WinForms program development environments. This online tutorial mainly talks about high level OCR toolkit in C# class programming. With this C# imaging OCR SDK, users are supposed to extract text from various images like Jpeg, Png, Bmp, Gif, Tiff and scanned PDF document, and output to text file, SVG image or PDF file rapidly. So, if you want to deploy OCR recognition, RasterEdge XImage.OCR for .NET is your best choice. Flexible C# OCR recognition, detecting and setting options are provided for better performance.

Major Features

RasterEdge XImage.OCR for .NET provides you with mature functions to recognize characters out of images and documents types that are supported by RasterEdge .NET Document Imaging SDK.

Free to implement reliable and high performance Optical Character Recognition in any .NET development environment

Simple to integrate .NET Imaging OCR Software into C# and VB.NET programming applications

Support scanning and recognizing MICR E-13B, OCR-A, and OCR-B fonts from check at fast speed

Support using this OCR SDK to extract image and document text content that in various popular languages

Able to recognize images captured by a digital camera, scanned document or image-only PDF using C# OCR toolkit

Support both monochrome and bitonal color image recognition for scanned documents and pictures in C#

Complete and rapid report of extracted text, including size, font, location, character attribute, etc.

Steps to Extract Text from Image

Initialize the language resources.

Set enabed languages, the default language is english.

Load an image file or page.（Bitmap or BasePage object.）

Recognize characters from input image.

If it can't get text successfully, please try as follows:

  Cleanup the image or Convert BasePage to Bitmap with higher resolution by calling method ConvertToImage(int resolution).

// Set the training data path. Please put eng.traineddata (for English) under the directory you specified.
OCRHandler.SetTrainResourcePath(@"c:\source\");
//Load an image.
Bitmap img = new Bitmap(@"C:\page.jpeg");

// Modify the resolution of image, and make it clear enough.
img.SetResolution(192f, 192f);

//If you are loading a document(PDF, TIFF, Office, or more formats).
//Get BasePage and Convert it to bitmap with high resolution.
BaseDocument doc = newTIFFDocument(@"C:\input.tif");
BasePage page = doc.GetPage(0);
//The default resolution is 96, if set higher, it will be better to recognize the text.
Bitmap image = page.ConvertToImage(192);

// Recognize  characters from this image. Default language is English.
OCRPage ocrPage = OCRHandler.Import(img);
ocrPage.Recognize();

Console.WriteLine(ocrPage.GetText());

Save the recongnized text to .txt file.

Sample Code

RasterEdge.com provides free sample code for using our .NET OCR SDK. You may click below to see an example of using Visual C# programming code to extract text from Jpeg, and output to text file and PDF file.  Please note, you need to firstly integrate four assemblies into your C#.NET project as references.

Add References

  RasterEdge.XImage.OCR.dll

  RasterEdge.XImage.OCR.Tesseract.dll

  RasterEdge.Imaging.Basic.dll

  RasterEdge.Imaging.Basic.Codec.dll

  RasterEdge.Imaging.Drawing.dll

  RasterEdge.Imaging.Font.dll

  RasterEdge.Imaging.Processing.dll

  RasterEdge.XImage.AdvancedCleanup.Core.dll

Using Namespaces

  using RasterEdge.Imaging.Raster.Core;

  using RasterEdge.XImage.OCR;

Note: When you get the error "Could not load file or assembly 'RasterEdge.Imaging.Basic' or any other assembly or one of its dependencies. An attempt to load a program with an incorrect format", please check your configure as follows:

       If you are using x64 libraries/dlls, Right click the project -> Properties -> Build -> Platform target: x64.

       If using x86, the platform target should be x86.

// Set the training data path. Please put eng.traineddata (for English) under the directory you specified.
OCRHandler.SetTrainResourcePath(@"c:\source\");

//Load an image.
Bitmap img = new Bitmap(@"C:\page.jpeg");

// Resize image to improve accuracy. If the image is clear enough, skip this.
img.SetResoulution(192f, 192f);

// Recognize  characters from this image. Default language is English.
OCRPage page = OCRHandler.Import(img);
page.Recognize();

Console.WriteLine(page.GetText());

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