ByteScout Text Recognition SDK – VB.NET – Use Image Preprocessing Filters

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ByteScout Text Recognition SDK – VB.NET – Use Image Preprocessing Filters

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How to use image preprocessing filters in VB.NET with ByteScout Text Recognition SDK

Tutorial on how to use image preprocessing filters in VB.NET

These source code samples are listed and grouped by their programming language and functions they use. ByteScout Text Recognition SDK: the software development kit for automatic text recognition and OCR from pdf documents and images. Can recognize English and non-English languages. It can use image preprocessing filters in VB.NET.

VB.NET code samples for VB.NET developers help to speed up coding of your application when using ByteScout Text Recognition SDK. Follow the instructions from the scratch to work and copy the VB.NET code. Test VB.NET sample code examples whether they respond your needs and requirements for the project.

Trial version of ByteScout Text Recognition SDK can be downloaded for free from our website. It also includes source code samples for VB.NET and other programming languages.

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Module1.vb

      Imports Bytescout.TextRecognition

Module Module1

    Sub Main()

        Dim inputDocument As String = ".\skewed.png"
        Dim outputDocument As String = ".\result.txt"

        ' Create and activate TextRecognizer instance
        Using textRecognizer As TextRecognizer = New TextRecognizer("demo", "demo")

            Try
                ' Load document (image or PDF)
                textRecognizer.LoadDocument(inputDocument)

                ' Set the location of OCR language data files
                textRecognizer.OCRLanguageDataFolder = "c:\Program Files\ByteScout Text Recognition SDK\ocrdata_best\"

                ' Set OCR language.
                ' "eng" for english, "deu" for German, "fra" for French, "spa" for Spanish, etc. - according to files in "ocrdata" folder
                ' Find more language files at https://github.com/bytescout/ocrdata
                textRecognizer.OCRLanguage = "eng" 


                ' Add deskew filter that automatically rotates the image to make the text horizontal.
                ' Note, it analyzes the left edge of scanned text. Any dark artifacts may prevent 
                ' the correct angle detection.
                textRecognizer.ImagePreprocessingFilters.AddDeskew()

                ' Other filters that may be useful to improve recognition
                ' (note, the filters are applied in the order they were added):

                ' Improve image contrast.
                'textRecognizer.ImagePreprocessingFilters.AddContrast()

                ' Apply gamma correction.
                'textRecognizer.ImagePreprocessingFilters.AddGammaCorrection()

                ' Apply median filter. Helps to remove noise.
                'textRecognizer.ImagePreprocessingFilters.AddMedian()

                ' Apply dilate filter. Helps to cure symbols erosion.
                'textRecognizer.ImagePreprocessingFilters.AddDilate()

                ' Lines removers. Removing borders of some tables may improve the recognition.
                'textRecognizer.ImagePreprocessingFilters.AddHorizontalLinesRemover()
                'textRecognizer.ImagePreprocessingFilters.AddVerticalLinesRemover()

                
                ' Recognize text from all pages and save it to file
                textRecognizer.SaveText(outputDocument)

                ' Open the result file in default associated application (for demo purposes)
                Process.Start(outputDocument)

            Catch exception As Exception

                Console.WriteLine(exception)

            End Try

        End Using

    End Sub

End Module