【官方框架地址】

github.com/shimat/opencvsharp
【算法介绍】

采用opencv算法实现文字区域提取，步骤如下：
（1）形态学操作
（2）查找轮廓
（3）筛选那些面积小的
（4）面积小的都筛选
（5）找到最小的矩形

【效果展示】

原图

提取结果：

【实现部分代码】

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

namespace FIRC
{
    public partial class Form1 : Form
    {
        Mat src = new Mat();

        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            OpenFileDialog openFileDialog = new OpenFileDialog();
            openFileDialog.Filter = "图文件(*.*)|*.jpg;*.png;*.jpeg;*.bmp";
            openFileDialog.RestoreDirectory = true;
            openFileDialog.Multiselect = false;
            if (openFileDialog.ShowDialog() == DialogResult.OK)
            {
              
                src = Cv2.ImRead(openFileDialog.FileName);
                pictureBox1.Image = OpenCvSharp.Extensions.BitmapConverter.ToBitmap(src);


            }


        }

        private void button2_Click(object sender, EventArgs e)
        {
            if(pictureBox1.Image==null)
            {
                return;
            }
          
            var resultMat =RegionManager.FindTextRegion(src);
            pictureBox2.Image= OpenCvSharp.Extensions.BitmapConverter.ToBitmap(resultMat); //Mat转Bitmap
        }

        private void Form1_Load(object sender, EventArgs e)
        {
           
        }

        private void button3_Click(object sender, EventArgs e)
        {


        }
    }
}

【源码下载】

https://download.csdn.net/download/FL1623863129/88706018
【测试环境】

vs2019
netframework4.7.2
opencvsharp4.8.0