SharpTesseract/TestVideo/Zone.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Drawing;
using Emgu.CV.Structure;
using Emgu.CV;
using Emgu.CV.OCR;

namespace TestVideo
{
    internal class Zone
    {
        [Flags]
        public enum ZoneType { Standings, Gaps, LastLapPace }

        private ZoneType _type;
        private Rectangle _zoneArea;
        private Bitmap _zoneData;
        private string _rawText;
        private string[] _cleanText;
        private string _name;
        private ZoneType Type { get => _type; set => _type = value; }
        public Rectangle ZoneArea { get => _zoneArea; private set => _zoneArea = value; }
        public Bitmap ZoneData { get => _zoneData; private set => _zoneData = value; }
        public string RawText { get => _rawText; private set => _rawText = value; }
        public string[] CleanText { get => _cleanText; private set => _cleanText = value; }
        public string Name { get => _name; private set => _name = value; }

        public Zone(Rectangle area, ZoneType type, string name)
        {
            ZoneArea = area;
            Type = type;
            Name = name;
        }
        public void Update(Bitmap data)
        {
            ZoneData = data;
            RawText = GetRawText(ZoneData);
            CleanText = GetCleanText(RawText);
        }
        //Original method : http://leonwoo-tech.blogspot.com/2018/06/tip-how-to-properly-setup-opencv-ocr-to.html
        private string GetRawText(Bitmap inputBmp)
        {
            string result = "";

            string tesseractResult = Tesseract(inputBmp);
            string[] lettersData = tesseractResult.Split('\n');
            using (Graphics g = Graphics.FromImage(inputBmp))
            {
                foreach (string letterData in lettersData)
                {
                    string[] data = letterData.Split(' ');
                    //This data is in a format that we cant process
                    if (data.Length != 6)
                        break;

                    string letter = data[0];
                    //Point position = new Point(Convert.ToInt32(data[1]), Convert.ToInt32(data[2]));
                    //Size size = new Size(Convert.ToInt32(data[3]), Convert.ToInt32(data[4]));
                    Point position = new Point(Convert.ToInt32(data[1]), Convert.ToInt32(data[2]));
                    Size size = new Size(Convert.ToInt32(data[3]) - Convert.ToInt32(data[1]), Convert.ToInt32(data[4]) - Convert.ToInt32(data[2]));
                    Point correctedPosition = new Point(position.X, inputBmp.Height - position.Y - size.Height);
                    int unknownData = Convert.ToInt32(data[5]);

                    //A neat post processing Idea would be to separate letters that have a unusually big difference in X or Y axis to try and recognise words

                    //Use the data
                    result += letter;
                    //g.DrawRectangle(new Pen(Brushes.Red, 5), new Rectangle(position, size));
                    g.DrawRectangle(new Pen(Brushes.Red, 3), new Rectangle(correctedPosition, size));
                }
            }

            return result;
        }
        private string[] GetCleanText(string rawText)
        {
            //TODO

            return new string[] { rawText };
        }

        private string Tesseract(Bitmap inputBmp)
        {
            string result = "";
            //To use this toImage you need : NuGet\Install-Package Emgu.CV.Bitmap -Version 4.5.5.4823
            inputBmp = PrepareImage(inputBmp);
            ZoneData = inputBmp;
            Image<Bgr, byte> emguImage = inputBmp.ToImage<Bgr, byte>();

            using (var image = emguImage)
            {
                using (Tesseract tesseractOcrProvider = new Tesseract(AppDomain.CurrentDomain.BaseDirectory + "\\Data", "eng", OcrEngineMode.Default))
                {
                    tesseractOcrProvider.SetImage(image);
                    tesseractOcrProvider.Recognize();
                    result = tesseractOcrProvider.GetBoxText().TrimEnd();
                }
            }
            return result;
        }
        private Bitmap PrepareImage(Bitmap inputImage)
        {
            for (int y = 0; y < inputImage.Height; y++)
            {
                for (int x = 0; x < inputImage.Width; x++)
                {
                    //We transform the RGB image into a Grayscale one
                    //Grayscale = 0.299R + 0.587G + 0.114B
                    Color color = inputImage.GetPixel(x, y);
                    int grayScaleValue = Convert.ToInt32(0.299 * (float)color.R + 0.587 * (float)color.G + 0.114 * (float)color.B);
                    int finalValue = 0;
                    //Then we make it boolean, either black or white
                    if (grayScaleValue > 255 / 2)
                        finalValue = 255;
                    inputImage.SetPixel(x, y, Color.FromArgb(finalValue, finalValue, finalValue));
                }
            }
            //inputImage.Save("C:/TEST/test.png",ImageFormat.Png);
            return inputImage;
        }
    }
}