How to implement and do OCR in a C# project?

c#, ocr

Solution

If anyone is looking into this, I've been trying different options and the following approach yields very good results. The following are the steps to get a working example:

- Add .NET Wrapper for tesseract to your project. It can be added via NuGet package `Install-Package Tesseract`(https://github.com/charlesw/tesseract).

- Go to the Downloads section of the official Tesseract project (https://code.google.com/p/tesseract-ocr/ EDIT: It's now located here: https://github.com/tesseract-ocr/langdata).

- Download the preferred language data, example: `tesseract-ocr-3.02.eng.tar.gz English language data for Tesseract 3.02`.

- Create `tessdata` directory in your project and place the language data files in it.

- Go to `Properties` of the newly added files and set them to copy on build.

- Add a reference to `System.Drawing`.

- From .NET Wrapper repository, in the `Samples` directory copy the sample `phototest.tif` file into your project directory and set it to copy on build.

- Create the following two files in your project (just to get started):

Program.cs

using System;
using Tesseract;
using System.Diagnostics;

namespace ConsoleApplication
{
    class Program
    {
        public static void Main(string[] args)
        {
            var testImagePath = "./phototest.tif";
            if (args.Length > 0)
            {
                testImagePath = args[0];
            }

            try
            {
                var logger = new FormattedConsoleLogger();
                var resultPrinter = new ResultPrinter(logger);
                using (var engine = new TesseractEngine(@"./tessdata", "eng", EngineMode.Default))
                {
                    using (var img = Pix.LoadFromFile(testImagePath))
                    {
                        using (logger.Begin("Process image"))
                        {
                            var i = 1;
                            using (var page = engine.Process(img))
                            {
                                var text = page.GetText();
                                logger.Log("Text: {0}", text);
                                logger.Log("Mean confidence: {0}", page.GetMeanConfidence());

                                using (var iter = page.GetIterator())
                                {
                                    iter.Begin();
                                    do
                                    {
                                        if (i % 2 == 0)
                                        {
                                            using (logger.Begin("Line {0}", i))
                                            {
                                                do
                                                {
                                                    using (logger.Begin("Word Iteration"))
                                                    {
                                                        if (iter.IsAtBeginningOf(PageIteratorLevel.Block))
                                                        {
                                                            logger.Log("New block");
                                                        }
                                                        if (iter.IsAtBeginningOf(PageIteratorLevel.Para))
                                                        {
                                                            logger.Log("New paragraph");
                                                        }
                                                        if (iter.IsAtBeginningOf(PageIteratorLevel.TextLine))
                                                        {
                                                            logger.Log("New line");
                                                        }
                                                        logger.Log("word: " + iter.GetText(PageIteratorLevel.Word));
                                                    }
                                                } while (iter.Next(PageIteratorLevel.TextLine, PageIteratorLevel.Word));
                                            }
                                        }
                                        i++;
                                    } while (iter.Next(PageIteratorLevel.Para, PageIteratorLevel.TextLine));
                                }
                            }
                        }
                    }
                }
            }
            catch (Exception e)
            {
                Trace.TraceError(e.ToString());
                Console.WriteLine("Unexpected Error: " + e.Message);
                Console.WriteLine("Details: ");
                Console.WriteLine(e.ToString());
            }
            Console.Write("Press any key to continue . . . ");
            Console.ReadKey(true);
        }



        private class ResultPrinter
        {
            readonly FormattedConsoleLogger logger;

            public ResultPrinter(FormattedConsoleLogger logger)
            {
                this.logger = logger;
            }

            public void Print(ResultIterator iter)
            {
                logger.Log("Is beginning of block: {0}", iter.IsAtBeginningOf(PageIteratorLevel.Block));
                logger.Log("Is beginning of para: {0}", iter.IsAtBeginningOf(PageIteratorLevel.Para));
                logger.Log("Is beginning of text line: {0}", iter.IsAtBeginningOf(PageIteratorLevel.TextLine));
                logger.Log("Is beginning of word: {0}", iter.IsAtBeginningOf(PageIteratorLevel.Word));
                logger.Log("Is beginning of symbol: {0}", iter.IsAtBeginningOf(PageIteratorLevel.Symbol));

                logger.Log("Block text: \"{0}\"", iter.GetText(PageIteratorLevel.Block));
                logger.Log("Para text: \"{0}\"", iter.GetText(PageIteratorLevel.Para));
                logger.Log("TextLine text: \"{0}\"", iter.GetText(PageIteratorLevel.TextLine));
                logger.Log("Word text: \"{0}\"", iter.GetText(PageIteratorLevel.Word));
                logger.Log("Symbol text: \"{0}\"", iter.GetText(PageIteratorLevel.Symbol));
            }
        }
    }
}

FormattedConsoleLogger.cs

using System;
using System.Collections.Generic;
using System.Text;
using Tesseract;

namespace ConsoleApplication
{
    public class FormattedConsoleLogger
    {
        const string Tab = "    ";
        private class Scope : DisposableBase
        {
            private int indentLevel;
            private string indent;
            private FormattedConsoleLogger container;

            public Scope(FormattedConsoleLogger container, int indentLevel)
            {
                this.container = container;
                this.indentLevel = indentLevel;
                StringBuilder indent = new StringBuilder();
                for (int i = 0; i < indentLevel; i++)
                {
                    indent.Append(Tab);
                }
                this.indent = indent.ToString();
            }

            public void Log(string format, object[] args)
            {
                var message = String.Format(format, args);
                StringBuilder indentedMessage = new StringBuilder(message.Length + indent.Length * 10);
                int i = 0;
                bool isNewLine = true;
                while (i < message.Length)
                {
                    if (message.Length > i && message[i] == '\r' && message[i + 1] == '\n')
                    {
                        indentedMessage.AppendLine();
                        isNewLine = true;
                        i += 2;
                    }
                    else if (message[i] == '\r' || message[i] == '\n')
                    {
                        indentedMessage.AppendLine();
                        isNewLine = true;
                        i++;
                    }
                    else
                    {
                        if (isNewLine)
                        {
                            indentedMessage.Append(indent);
                            isNewLine = false;
                        }
                        indentedMessage.Append(message[i]);
                        i++;
                    }
                }

                Console.WriteLine(indentedMessage.ToString());

            }

            public Scope Begin()
            {
                return new Scope(container, indentLevel + 1);
            }

            protected override void Dispose(bool disposing)
            {
                if (disposing)
                {
                    var scope = container.scopes.Pop();
                    if (scope != this)
                    {
                        throw new InvalidOperationException("Format scope removed out of order.");
                    }
                }
            }
        }

        private Stack<Scope> scopes = new Stack<Scope>();

        public IDisposable Begin(string title = "", params object[] args)
        {
            Log(title, args);
            Scope scope;
            if (scopes.Count == 0)
            {
                scope = new Scope(this, 1);
            }
            else
            {
                scope = ActiveScope.Begin();
            }
            scopes.Push(scope);
            return scope;
        }

        public void Log(string format, params object[] args)
        {
            if (scopes.Count > 0)
            {
                ActiveScope.Log(format, args);
            }
            else
            {
                Console.WriteLine(String.Format(format, args));
            }
        }

        private Scope ActiveScope
        {
            get
            {
                var top = scopes.Peek();
                if (top == null) throw new InvalidOperationException("No current scope");
                return top;
            }
        }
    }
}

Problem

I ve been searching for a while and all that i ve seen some OCR library requests. I would like to know how to implement the purest, easy to install and use OCR library with detailed info for installation into a C# project. If posible, I just wanna implement it like a usual dll reference... Example: ``` using org.pdfbox.pdmodel; using org.pdfbox.util; ``` Also a little OCR code example would be nice, such as: ``` public string OCRFromBitmap(Bitmap Bmp) { Bmp.Save(temppath, System.Drawing.Imaging.ImageFormat.Tiff); string OcrResult = Analyze(temppath); File.Delete(temppath); return OcrResult; } ``` So please consider that I'm not familiar to OCR projects and give me an answer like talking to a dummy. Edit: I guess people misunderstood my request. I wanted to know how to implement those open source OCR libraries to a C# project and how to use them. The link given as dup is not giving answers that I requested at all.

Original source