ByteScout Barcode Reader SDK – C# – Image Preprocessing Filters

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ByteScout Barcode Reader SDK – C# – Image Preprocessing Filters

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ByteScout-BarCode-Reader-SDK-C-sharp-Image-Preprocessing-Filters.pdf

image preprocessing filters in C# and ByteScout BarCode Reader SDK

How to use ByteScout BarCode Reader SDK for image preprocessing filters in C#

These source code samples are listed and grouped by their programming language and functions they use. ByteScout BarCode Reader SDK helps with image preprocessing filters in C#. ByteScout BarCode Reader SDK is the SDK for reading of barcodes from PDF, images and live camera or video. Almost every common type like Code 39, Code 128, GS1, UPC, QR Code, Datamatrix, PDF417 and many others are supported. Supports noisy and defective images and docs. Includes optional documents splitter and merger for pdf and tiff based on found barcodess. Batch mode is supported for superior performance using multiple threads. Decoded values are easily exported to JSON, CSV, XML and to custom format.

You will save a lot of time on writing and testing code as you may just take the code below and use it in your application. Follow the instruction from the scratch to work and copy and paste code for C# into your editor. Enhanced documentation and tutorials are available along with installed ByteScout BarCode Reader SDK if you’d like to dive deeper into the topic and the details of the API.

On our website you may get trial version of ByteScout BarCode Reader SDK for free. Source code samples are included to help you with your C# application.

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Program.cs

      using System;
using Bytescout.BarCodeReader;

namespace ImagePreprocessingFilters
{
    /// <summary>
    /// This exmaple demonstrates the use of image filters to improve the decoding or speed.
    /// </summary>
    class Program
    {
        static void Main()
        {
            using (Reader reader = new Reader("demo", "demo"))
            {
                // Set barcode type to find
                reader.BarcodeTypesToFind.Code128 = true;


                // WORKING WITH LOW CONTRAST BARCODE IMAGES

                // Add contrast adjustment for low-contrast image
                reader.ImagePreprocessingFilters.AddContrast(40);

                Console.WriteLine("Image {0}", "low-contrast-barcode.png");
                
                FoundBarcode[] barcodes = reader.ReadFrom("low-contrast-barcode.png");

                if (barcodes.Length == 0)
                    Console.WriteLine("No barcode found!");
                else 
                    foreach (FoundBarcode barcode in barcodes)
                        Console.WriteLine("Found barcode {0} with value '{1}'", barcode.Type, barcode.Value);

                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");

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

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

                if (barcodes.Length == 0)
                    Console.WriteLine("No barcode found!");
                else
                    foreach (FoundBarcode barcode in barcodes)
                        Console.WriteLine("Found barcode {0} with value '{1}'", barcode.Type, barcode.Value);

                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(2d); // enlarge twice

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

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

                if (barcodes.Length == 0)
                    Console.WriteLine("No barcode found!");
                else
                    foreach (FoundBarcode barcode in barcodes)
                        Console.WriteLine("Found barcode {0} with value '{1}'", barcode.Type, barcode.Value);

                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)
                    Console.WriteLine("No barcode found!");
                else
                    foreach (FoundBarcode barcode in barcodes)
                        Console.WriteLine("Found barcode {0} with value '{1}'", barcode.Type, barcode.Value);

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

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