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

Home
/
Articles
/
ByteScout Barcode Suite – VB.NET – Barcode image preprocessing filters with barcode reader sdk

printable version:
ByteScout-Barcode-Suite-VB-NET-Barcode-image-preprocessing-filters-with-barcode-reader-sdk.pdf

barcode image preprocessing filters with barcode reader sdk in VB.NET and ByteScout Barcode Suite

Learn to code barcode image preprocessing filters with barcode reader sdk in VB.NET: How-To tutorial

Here you may get thousands pre-made source code samples for simple implementation in your own programming VB.NET projects. ByteScout Barcode Suite was made to help with barcode image preprocessing filters with barcode reader sdk in VB.NET. ByteScout Barcode Suite is the bundle that privides 3 SDK products to generate barcodes (Barcode SDK), read barcodes (Barcode Reaer SDK) and read and write spreadsheets (Spreadsheet SDK).

Save time on writing and testing code by using the code below and use it in your application. Follow the steps-by-step instructions from the scratch to work and copy and paste code for VB.NET into your editor. VB.NET application implementation mostly involves various stages of the software development so even if the functionality works please check it with your data and the production environment.

ByteScout Barcode Suite free trial version is available for download from our website. Free trial also includes programming tutorials along with source code samples.

On-demand (REST Web API) version:
Web API (on-demand version)

On-premise offline SDK for Windows:
60 Day Free Trial (on-premise)

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