当前位置：首页 > news >正文

C# 通用OCR识别

news 来源：原创 2025/5/14 6:56:35

一、前言

通过查看网络资料以及书籍资料，发现大多数OCR识别功能都是基于Python语言开发的，对于习惯使用C# 开发语言的程序猿们，岂不是一件很苦恼的事！当然想学习Python，掌握多一项技能也并不是坏事！为了方便使用，想使用C# 的往下看（或需要使用当作工作辅助也行，资源下载在最后有链接）。

二、开发要求

1、图形处理库Clipper、Emgu.CV
2、高性能推理引擎 Microsoft.ML.OnnxRuntime
3、借用PaddleOCR模型
4、现有功能，选择照片识别、截图识别，选择PDF文件识别

三、部分代码

using Emgu.CV;
using OcrDemo.Helpers;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;namespace OcrDemo
{public partial class Form1 : Form{public Form1(){InitializeComponent();}private string fileFilter = "所有文件 (*.*)|*.*|bmp|*.bmp|jpg|*.jpg|jpeg|*.jpeg|png|*.png";private Bitmap bmp;  private string outPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "output");private Stopwatch stopwatch = new Stopwatch();private string filePath = "";private int threadNum = 4;private OcrLite ocrEngin;private void Form1_Load(object sender, EventArgs e){try{if (!Directory.Exists(outPath)){Directory.CreateDirectory(outPath);}splitContainer1.SplitterDistance = (int)(splitContainer1.Width * 0.5);splitContainer2.SplitterDistance = (int)(splitContainer2.Width * 0.5);string appPath = AppDomain.CurrentDomain.BaseDirectory;string appDir = Directory.GetParent(appPath).FullName;}catch (Exception ex){SetMessge(ex.Message);}}private void SetMessge(string info, int infoType = 0){//info = DataHelper.DateFormat(DateTime.Now) + "" + info + "\n";info =  info + "\n";if (this.InvokeRequired){// 如果需要跨线程调用，则使用 Invoke 方法this.Invoke(new Action(() =>{rTB_Message.AppendText(info);// 滚动文本框以使光标所在位置可见//rTB_ResultInfo.ScrollToCaret();// 选中插入点rTB_Message.Focus();}));}else{// 如果在 UI 线程中，则直接更新控件rTB_Message.AppendText(info);// 滚动文本框以使光标所在位置可见//rTB_ResultInfo.ScrollToCaret();// 选中插入点rTB_Message.Focus();}}private void tool_bt_select_Click(object sender, EventArgs e){OpenFileDialog ofd = new OpenFileDialog();ofd.Filter = fileFilter;if (ofd.ShowDialog() == DialogResult.OK){Application.DoEvents();filePath = ofd.FileName;var imagebyte = File.ReadAllBytes(filePath);bmp = new Bitmap(new MemoryStream(imagebyte));pictureBox1.Image = bmp;rTB_Message.Clear();if (bmp == null) return;stopwatch.Restart();OcrResult ocrResult = ocrEngin.Detect(filePath, padding, imgResize, boxScoreThresh, boxThresh, unClipRatio, doAngle, mostAngle);stopwatch.Stop();SetMessge(ocrResult.StrRes);SetMessge("------------------------------");//SetMessge(ocrResult.ToString());SetMessge($"--------------耗时: {stopwatch.ElapsedMilliseconds} 毫秒----------------");pictureBox2.Image = ocrResult.BoxImg.ToBitmap();}}private void tool_bt_screenshot_Click(object sender, EventArgs e){this.Hide();System.Threading.Thread.Sleep(200);Application.DoEvents();ScreenCapturer.ScreenCapturerTool screenCapturer = new ScreenCapturer.ScreenCapturerTool();if (screenCapturer.ShowDialog() == DialogResult.OK){bmp = (Bitmap)screenCapturer.Image;string newFiles = outPath+"\\" + DataHelper.GetTimestamp() + ".jpg";bmp.Save(newFiles, ImageFormat.Jpeg);pictureBox1.Image = bmp;try{stopwatch.Restart();OcrResult ocrResult = ocrEngin.Detect(newFiles, padding, imgResize, boxScoreThresh, boxThresh, unClipRatio, doAngle, mostAngle);stopwatch.Stop();SetMessge(ocrResult.StrRes);SetMessge($"--------------耗时: {stopwatch.ElapsedMilliseconds} 毫秒----------------");//SetMessge(ocrResult.ToString());pictureBox2.Image = ocrResult.BoxImg.ToBitmap();}catch (Exception ex){SetMessge(ex.Message);}}this.Show();}private void tool_bt_PDF_Click(object sender, EventArgs e){OpenFileDialog ofd = new OpenFileDialog();ofd.Filter = "所有文件 (*.*)|*.*|PDF|*.pdf";if (ofd.ShowDialog() == DialogResult.OK){string pdfPath = ofd.FileName;// 1. 解析PDF获取页面图像using (var document = PdfDocument.Load(pdfPath)){string firstFiles = "";stopwatch.Restart();for (int pageIndex = 0; pageIndex < document.PageCount; pageIndex++){// 渲染PDF页面为图像using (var image = document.Render(pageIndex, 400, 800, false)){string newFiles = outPath + "\\" + DataHelper.GetTimestamp() + ".jpg";if (pageIndex == 0){firstFiles = newFiles;}image.Save(newFiles, ImageFormat.Jpeg);OcrResult ocrResult = ocrEngin.Detect(newFiles, padding, imgResize, boxScoreThresh, boxThresh, unClipRatio, doAngle, mostAngle);stopwatch.Stop();SetMessge(ocrResult.StrRes);}}if (firstFiles.Length > 0){var imagebyte = File.ReadAllBytes(firstFiles);pictureBox1.Image = new Bitmap(new MemoryStream(imagebyte));}//SetMessge(ocrResult.ToString());SetMessge($"--------------耗时: {stopwatch.ElapsedMilliseconds} 毫秒----------------");}}}}
}