C#身份证识别相关技术

最近研究C#相关的OCR技术，图像识别一般C和C++这种底层语言做的比较多，C#主要是依托一些封装好的组件进行调用，这里介绍一种身份证识别的方法。

环境搭建

下载地址：EmguCV官网

在File类别下下载这个EXE，进行安装，安装后在目录下能找相应组件，还有些应用的案例。

dll文件夹中的dll引用到C#项目中，x64，x86，tessdata对应OCR识别的类库和语言库，我tessdata中已添加中文语言包，将这三个文件夹放入程序执行文件夹中。

Demo

自己做的小Demo如图：身份证图片是百度上下载的

不得不说这个类库唯一弊端就是文字识别率太低，图像识别效果也不太好

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 Emgu.CV;
using Emgu.CV.OCR;
using Emgu.CV.Structure;
using System.IO;

namespace EmguCV
{
    public partial class Form1 : Form
    {
        Image<Gray, Byte> imageThreshold;
        public Form1()
        {
            InitializeComponent();
            pictureBox1.Enabled = false;
        }

        private void Form1_Load(object sender, EventArgs e)
        {



        }

        private void button1_Click(object sender, EventArgs e)
        {
            //第一个参数是语言包文件夹的地址，不写默认在执行文件夹下
            Tesseract _ocr = new Tesseract(@"", "chi_sim", OcrEngineMode.TesseractOnly);
            _ocr.SetImage(imageThreshold);
            _ocr.Recognize();
            String text = _ocr.GetUTF8Text();
            this.textBox1.Text = text;
        }

        private void pictureBox2_Click(object sender, EventArgs e)
        {
            OpenFileDialog of = new OpenFileDialog();
            of.Title = "请选择图片";
            if (of.ShowDialog() == DialogResult.OK)
            {
                string file = of.FileName;
                Image img = Image.FromFile(file);
                pictureBox1.Image = img;
            }
            Bitmap bitmap = (Bitmap)this.pictureBox1.Image;
            Image<Bgr, Byte> imageSource = new Image<Bgr, byte>(bitmap);
            Image<Gray, Byte> imageGrayscale = imageSource.Convert<Gray, Byte>();
            imageGrayscale = randon(imageGrayscale);
            imageThreshold = imageGrayscale.ThresholdBinary(new Gray(100), new Gray(255));
            this.pictureBox2.Image = imageThreshold.ToBitmap();
        }
        /// <summary>
        /// 旋转校正
        /// </summary>
        /// <param name="imageInput"></param>
        /// <returns></returns>
        private Image<Gray, Byte> randon(Image<Gray, Byte> imageInput)//图像投影旋转法倾斜校正子函数定义
        {
            int nwidth = imageInput.Width;
            int nheight = imageInput.Height;
            int sum;
            int SumOfCha;
            int SumOfChatemp = 0;
            int[] sumhang = new int[nheight];
            Image<Gray, Byte> resultImage = imageInput;
            Image<Gray, Byte> ImrotaImage;
            //20度范围内的调整
            for (int ang = -20; ang < 20; ang = ang + 1)
            {
                ImrotaImage = imageInput.Rotate(ang, new Gray(1));
                for (int i = 0; i < nheight; i++)
                {
                    sum = 0;
                    for (int j = 0; j < nwidth; j++)
                    {
                        sum += ImrotaImage.Data[i, j, 0];
                    }
                    sumhang[i] = sum;
                }
                SumOfCha = 0;
                for (int k = 0; k < nheight - 1; k++)
                {
                    SumOfCha = SumOfCha + (Math.Abs(sumhang[k] - sumhang[k + 1]));
                }
                if (SumOfCha > SumOfChatemp)
                {
                    resultImage = ImrotaImage;
                    SumOfChatemp = SumOfCha;
                }
            }
            return resultImage;
        }

        private void pictureBox1_Click(object sender, EventArgs e)
        {

        }
    }
}