using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using Tesseract;

namespace TesseractDemo
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        //選圖片并調(diào)用ocr識(shí)別方法
        private void btnRec_Click(object sender, EventArgs e)
        {
            //openFileDialog1.Filter = "";
            if (openFileDialog1.ShowDialog() == DialogResult.OK)
            {
                var imgPath = openFileDialog1.FileName;
                pictureBox1.Image=Image.FromFile(imgPath);
                string strResult = ImageToText(imgPath);
                if (string.IsNullOrEmpty(strResult))
                {
                    txtResult.Text = "無法識(shí)別";
                }
                else
                {
                    txtResult.Text = strResult;
                }
            }
        }
        //調(diào)用tesseract實(shí)現(xiàn)OCR識(shí)別
        public string ImageToText(string imgPath)
        {
            using (var engine = new TesseractEngine("tessdata", "eng", EngineMode.Default))
            {
                using (var img = Pix.LoadFromFile(imgPath))
                {
                    using (var page = engine.Process(img))
                    {
                        return page.GetText();
                    }
                }
            }
        }
    }
}

//用opencv進(jìn)行降噪處理再ocr識(shí)別
        private void button3_Click(object sender, EventArgs e)
        {
            //從網(wǎng)上讀取一張圖片
            string imgUrl = "https://service.cheshi.com/user/validate/validatev3.php";
            MemoryStream ms = ReadImgFromWeb(imgUrl);
            Image img = Image.FromStream(ms);
            pictureBox1.Image = img;

            //降噪
            Mat simg = Mat.FromStream(ms, ImreadModes.Grayscale);
            Cv2.ImShow("Input Image", simg);
            //閾值操作 閾值參數(shù)可以用一些可視化工具來調(diào)試得到
            Mat ThresholdImg = simg.Threshold(29, 255, ThresholdTypes.Binary);
            Cv2.ImShow("Threshold", ThresholdImg);
            Cv2.ImWrite("d:\\img.png", ThresholdImg);
            
            textBox1.Text= ImageToText("d:\\img.png");
        }
        
        /// <summary>
        /// 從網(wǎng)上讀取一張圖片
        /// </summary>
        /// <param name="Url"></param>
        public MemoryStream ReadImgFromWeb(string Url)
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url);
            request.Credentials = CredentialCache.DefaultCredentials; // 添加授權(quán)證書
            request.UserAgent = "Microsoft Internet Explorer";
            WebResponse response = request.GetResponse();
            Stream s = response.GetResponseStream();
            byte[] data = new byte[1024];
            int length = 0;
            MemoryStream ms = new MemoryStream();
            while ((length = s.Read(data, 0, data.Length)) > 0)
            {
                ms.Write(data, 0, length);
            }
            ms.Seek(0, SeekOrigin.Begin);
            //pictureBox1.Image = Image.FromStream(ms);
            return ms;
        }