ByteScout Data Extraction Suite – VB.NET – Barcode image preprocessing filters with barcode reader sdk

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ByteScout Data Extraction Suite – VB.NET – Barcode image preprocessing filters with barcode reader sdk

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ByteScout-Data-Extraction-Suite-VB-NET-Barcode-image-preprocessing-filters-with-barcode-reader-sdk.pdf

barcode image preprocessing filters with barcode reader sdk in VB.NET using ByteScout Data Extraction Suite

How to apply ByteScout Data Extraction Suite for barcode image preprocessing filters with barcode reader sdk in VB.NET

ByteScout tutorials describe the stuff for programmers who use VB.NET. ByteScout Data Extraction Suite helps with barcode image preprocessing filters with barcode reader sdk in VB.NET. ByteScout Data Extraction Suite is the set that includes 3 SDK products for data extraction from PDF, scans, images and from spreadsheets: PDF Extractor SDK, Data Extraction SDK, Barcode Reader SDK.

The below SDK samples describe how to quickly make your application do barcode image preprocessing filters with barcode reader sdk in VB.NET with the help of ByteScout Data Extraction Suite. Follow the steps-by-step instructions from the scratch to work and copy and paste code for VB.NET into your editor. Further improvement of the code will make it more robust.

Trial version along with the source code samples for VB.NET can be downloaded from our website

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Module1.vb

      Imports Bytescout.BarCodeReader

Module Module1
    ''' <summary>
    ''' This exmaple demonstrates the use of image filters to improve the decoding or speed.
    ''' </summary>
    Sub Main()

        Using reader As New Reader("demo", "demo")

            ' Set barcode type to find
            reader.BarcodeTypesToFind.Code128 = True


            ' WORKING WITH LOW CONTRAST BARCODE IMAGES

            ' Add the contrast adjustment for the low contrast image
            reader.ImagePreprocessingFilters.AddContrast(40)

            Console.WriteLine("Image {0}", "low-contrast-barcode.png")

            ' -----------------------------------------------------------------------
            ' NOTE: We can read barcodes from specific page to increase performance .
            ' For sample please refer to "Decoding barcodes from PDF by pages" program.
            ' ----------------------------------------------------------------------- 

            Dim barcodes As FoundBarcode() = reader.ReadFrom("low-contrast-barcode.png")

            If barcodes.Length = 0 Then
                Console.WriteLine("No barcode found!")
            Else
                For Each barcode As FoundBarcode In barcodes
                    Console.WriteLine("Found barcode {0} with value '{1}'", barcode.Type, barcode.Value)
                Next
            End If

            reader.ImagePreprocessingFilters.Clear()
            Console.WriteLine()


            ' WORKING WITH NOISY BARCODE IMAGES

            ' Add the median filter to lower the noise
            reader.ImagePreprocessingFilters.AddMedian()

            Console.WriteLine("Image {0}", "noisy-barcode.png")

            barcodes = reader.ReadFrom("noisy-barcode.png")

            If barcodes.Length = 0 Then
                Console.WriteLine("No barcode found!")
            Else
                For Each barcode As FoundBarcode In barcodes
                    Console.WriteLine("Found barcode {0} with value '{1}'", barcode.Type, barcode.Value)
                Next
            End If

            reader.ImagePreprocessingFilters.Clear()
            Console.WriteLine()


            ' WORKING WITH DENSE AND ILLEGIBLE BARCODES

            ' Add the scale filter to enlarge the barcode to make gaps between bars more distinguishable
            reader.ImagePreprocessingFilters.AddScale(2) ' enlarge twice

            Console.WriteLine("Image {0}", "too-dense-barcode.png")

            barcodes = reader.ReadFrom("too-dense-barcode.png")

            If barcodes.Length = 0 Then
                Console.WriteLine("No barcode found!")
            Else
                For Each barcode As FoundBarcode In barcodes
                    Console.WriteLine("Found barcode {0} with value '{1}'", barcode.Type, barcode.Value)
                Next
            End If

            reader.ImagePreprocessingFilters.Clear()
            Console.WriteLine()


            ' REMOVE EMPTY MARGINS FROM IMAGE TO SPEED UP THE PROCESSING

            ' Add the crop filter to cut off empty margins from the image.
            ' This will not improve the recognition quality but may speed up the processing 
            ' if you enabled multiple barcode types to search. 
            reader.ImagePreprocessingFilters.AddCropDark()

            Console.WriteLine("Image {0}", "barcode-with-large-margins.png")

            barcodes = reader.ReadFrom("barcode-with-large-margins.png")

            If barcodes.Length = 0 Then
                Console.WriteLine("No barcode found!")
            Else
                For Each barcode As FoundBarcode In barcodes
                    Console.WriteLine("Found barcode {0} with value '{1}'", barcode.Type, barcode.Value)
                Next
            End If

            reader.ImagePreprocessingFilters.Clear()
            Console.WriteLine()

        End Using

        Console.WriteLine("Press any key to exit..")
        Console.ReadKey()

    End Sub

End Module