效果

说明
根据《百度办公文档识别C++离线SDKV1.2用户接入文档.pdf》，使用C++封装DLL，C#调用。

背景
为使客户、第三方开发者等能够更快速、方便的接入使用百度办公文档识别 SDK、促进百度 OCR产品赋能更多客户，特设计支持 c++语言的 Windows 高精通用文字识别 SDK，该 SDK 提供 pdf 转图文的能力和通过 pdf 识别文字并可以转存成 word 的能力。

SDK 简介
本 SDK 适应于 Windows 平台下的人脸识别系统, ,开发者可在 vs2015 下⾯进⾏开发（推荐使⽤，不保证其他版本 vs 都兼容）。SDK 采⽤ c++的动态库 dll 的⽅式。上层 UI 框架支持主流框架如QT,MFC 等。

自动批量授权
鉴权采用自动激活的方式进行授权，可参考 SDK 示例中，把申请到的授权 key 串码(仅支持批量授权)填入到 license 文件夹的 license.key 文件中，运行 SDK，即可自动激活生成授权文件 license.ini 在license 文件夹中。SDK 授权是通过接口方法 auth_from_file 实现，该方法参数分别是传入授权 key 的串码和授权文件 license.ini 的绝对路径。确保参数正确后，在 SDK 中运行了该方法，就会生成授权license.ini 文件。若授权正确，该方法的返回值为 0，若非 0，则为授权失败，错误原因可根据错误码参考后续文档查看。

离线授权
离线授权，采用从 sdk 附带的 license_tool 工具，bin 文件夹的 license_tool 下，双击 LicenseTool.exe，再点击拷贝，把设备指纹拷贝到剪贴板中，到百度 OCR 官网进行离线激活，填入得到的设备指纹后，从官网下载离线授权文件，解压，形成 license.key 和 license.ini 两个文件，替换到 SDK 中的 license 文件夹中，运行 SDK，若在 SDK 的授权方法 auth_from_file 中返回 0，则为通过了授权。（具体可参考SDK 中的授权代码示例）

代码

using HightOCRTest.Common;
using Newtonsoft.Json;
using OpenCvSharp;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Drawing;
using System.IO;
using System.Text;
using System.Windows.Forms;
 
namespace HightOCRTest
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
 
        string fileFilter = "*.*|*.bmp;*.jpg;*.jpeg;*.tiff;*.tiff;*.png";
        string image_path = "";
        bool isDraw = false;
        static IntPtr engine;
 
        private void button6_Click(object sender, EventArgs e)
        {
            //授权校验 初始化引擎
            string key = "";
            string licenseKeyPath = Application.StartupPath + "\\license\\license.key";
            string licenseFile = Application.StartupPath + "\\license\\license.ini";
            int res = -1;
            string ini_path = "";
 
            key = File.ReadAllText(licenseKeyPath);
 
            res = Native.init_license(key, licenseFile);
            if (res != 0)
            {
                MessageBox.Show(res.ToString());
                return;
            }
 
            engine = Native.create();
            if (engine == null)
            {
                MessageBox.Show("创建引擎失败！");
                return;
            }
 
            ini_path = Application.StartupPath + "\\resource";
            res = Native.init(engine, "", 6);
            if (res != 0)
            {
                MessageBox.Show(res.ToString());
                return;
            }
 
            MessageBox.Show("初始化成功！");
 
            button1.Enabled = true;
            button3.Enabled = true;
            button4.Enabled = true;
 
            button6.Enabled = false;
        }
 
        private void Form1_Load(object sender, EventArgs e)
        {
            //image_path = Application.StartupPath + "\\images\\1.jpg";
            image_path = Application.StartupPath + "\\test2.jpg";
            pictureBox1.Image = new Bitmap(image_path);
        }
 
        private void button2_Click(object sender, EventArgs e)
        {
            OpenFileDialog ofd = new OpenFileDialog();
            ofd.Filter = fileFilter;
            if (ofd.ShowDialog() != DialogResult.OK) return;
            pictureBox1.Image = null;
            image_path = ofd.FileName;
            pictureBox1.Image = new Bitmap(image_path);
            textBox1.Text = "";
        }
 
        StringBuilder ocr_result_texts = new StringBuilder(1024 * 10);
        StringBuilder ocr_result_words = new StringBuilder(1024 * 100);
 
        private void button1_Click(object sender, EventArgs e)
        {
            if (image_path == "")
            {
                return;
            }
 
            textBox1.Text = "";
            Application.DoEvents();
 
            ocr_result_texts.Clear();
            ocr_result_words.Clear();
            Mat image = new Mat(image_path);
            Stopwatch stopwatch = new Stopwatch();
            stopwatch.Start();
            int res = Native.ocr(engine, image.CvPtr, ocr_result_texts, ocr_result_words);
 
            stopwatch.Stop();
            double totalTime = stopwatch.Elapsed.TotalSeconds;
            textBox1.Text += $"耗时: {totalTime:F2}s";
            textBox1.Text += "\r\n-------------------\r\n";
 
            if (res == 0)
            {
                textBox1.Text += JsonConvert.SerializeObject(JsonConvert.DeserializeObject(ocr_result_texts.ToString()), Newtonsoft.Json.Formatting.Indented);
                textBox1.Text += "\r\n-------------------\r\n";
                textBox1.Text += JsonConvert.SerializeObject(JsonConvert.DeserializeObject(ocr_result_words.ToString()), Newtonsoft.Json.Formatting.Indented);
            }
            else
            {
 
                textBox1.Text = "识别失败";
            }
        }
 
        //绘制文字区域
        private void button3_Click(object sender, EventArgs e)
        {
            if (ocr_result_texts.Length == 0)
            {
                return;
            }
 
            Mat image = new Mat(image_path);
            List<OcrResTexts> lt = JsonConvert.DeserializeObject<List<OcrResTexts>>(ocr_result_texts.ToString());
            foreach (OcrResTexts item in lt)
            {
                string[] pts = item.coordinator.Split(' ');
 
                //多边形的顶点
                OpenCvSharp.Point[] points = new OpenCvSharp.Point[]
                {
                        new OpenCvSharp.Point(Convert.ToDouble( pts[0]), Convert.ToDouble( pts[1])),
                        new OpenCvSharp.Point(Convert.ToDouble( pts[2]), Convert.ToDouble( pts[3])),
                        new OpenCvSharp.Point(Convert.ToDouble( pts[4]), Convert.ToDouble( pts[5])),
                        new OpenCvSharp.Point(Convert.ToDouble( pts[6]), Convert.ToDouble( pts[7])),
                };
 
                // 绘制多边形
                Cv2.Polylines(image, new OpenCvSharp.Point[][] { points }, isClosed: true, color: new Scalar(0, 255, 0), thickness: 2);
            }
 
            if (pictureBox1.Image != null)
            {
                pictureBox1.Image.Dispose();
                pictureBox1.Image = null;
            }
 
            pictureBox1.Image = new Bitmap(image.ToMemoryStream());
            image.Dispose();
 
        }
        //堆代码 duidaima.com
        //绘制单字区域
        private void button4_Click(object sender, EventArgs e)
        {
            if (ocr_result_words.Length == 0)
            {
                return;
            }
 
            Mat image = new Mat(image_path);
            List<OcrResWords> lt = JsonConvert.DeserializeObject<List<OcrResWords>>(ocr_result_words.ToString());
            foreach (OcrResWords item in lt)
            {
                string[] pts = item.coordinator.Split(' ');
 
                //left top width height
 
                OpenCvSharp.Rect rect = new Rect((int)Convert.ToDouble(pts[0]), (int)Convert.ToDouble(pts[1]), (int)Convert.ToDouble(pts[2]), (int)Convert.ToDouble(pts[3]));
 
                Cv2.Rectangle(image, rect, color: new Scalar(255, 0, 0), thickness: 1);
 
            }
            if (pictureBox1.Image != null)
            {
                pictureBox1.Image.Dispose();
                pictureBox1.Image = null;
            }
 
            pictureBox1.Image = new Bitmap(image.ToMemoryStream());
            image.Dispose();
 
        }
 
        //识别小语种→
        private void button5_Click(object sender, EventArgs e)
        {
            //if (image_path == "")
            //{
            //    return;
            //}
 
            //textBox1.Text = "";
            //Application.DoEvents();
 
            //ocr_result_texts.Clear();
            //ocr_result_words.Clear();
            //Mat image = new Mat(image_path);
            //Stopwatch stopwatch = new Stopwatch();
            //stopwatch.Start();
            //int res = Native.ocr_other(engine, image.CvPtr, ocr_result_texts, ocr_result_words);
 
            //stopwatch.Stop();
            //double totalTime = stopwatch.Elapsed.TotalSeconds;
            //textBox1.Text += $"耗时: {totalTime:F2}s";
            //textBox1.Text += "\r\n-------------------\r\n";
 
            //if (res == 0)
            //{
            //    textBox1.Text += JsonConvert.SerializeObject(JsonConvert.DeserializeObject(ocr_result_texts.ToString()), Newtonsoft.Json.Formatting.Indented);
            //    textBox1.Text += "\r\n-------------------\r\n";
            //    textBox1.Text += JsonConvert.SerializeObject(JsonConvert.DeserializeObject(ocr_result_words.ToString()), Newtonsoft.Json.Formatting.Indented);
            //}
            //else
            //{
 
            //    textBox1.Text = "识别失败";
            //}
        }
    }
}