最近研究C#相關(guān)的OCR技術(shù)，圖像識別一般C和C++這種底層語言做的比較多，C#主要是依托一些封裝好的組件進(jìn)行調(diào)用，這里介紹三種身份證識別的方法。

一：調(diào)用大公司API接口，百度、云脈，文通科技都有相關(guān)的API介紹。
二：調(diào)用圖像處理類庫，EmguCV是OpenCV的一個(gè)跨平臺的.Net封裝，該封裝也可以被編譯到Mono平臺和允許在Windows、Mac OS、Android、iPhone、iPad等多個(gè)平臺上運(yùn)行
三：調(diào)用Office2007 組件

一、證件識別API接口

以聚合數(shù)據(jù)中的API接口為例，因?yàn)楣俜紸PI沒有提供C#的調(diào)用方式，網(wǎng)址如下：證件識別接口

/// 

/// 上傳圖片

/// 

/// 

public static string CardUpload()

{

    try

    {

        string appkey = "網(wǎng)站自己申請的key"; //配置您申請的appkey         

        HttpPostedFile file = HttpContext.Current.Request.Files[0];

        string url = "http://api2.juheapi.com/cardrecon/upload";

        var parameters = new Dictionary<string, string>();

        parameters.Add("key", appkey);

        parameters.Add("cardType", "2");

        string result = HttpPostData(url, 60000, "pic", file.InputStream, parameters);

        JObject info = JObject.Parse(JObject.Parse(result)["result"].ToString());

        var cardInfo = new

        {

            name = info["姓名"],

            card = info["公民身份號碼"]

        };

        return cardInfo.ToJson();

    }

    catch (Exception ex)

    {

        return ex.ToString();

    }

}

/// 

/// Post調(diào)用API

/// 

/// api地址

/// 訪問超時(shí)時(shí)間

/// 文件參數(shù)名

/// 文件流

/// 參數(shù)列表

/// 結(jié)果集

private static string HttpPostData(string url, int timeOut, string fileKeyName,

                           Stream file, Dictionary<string, string> stringDict)

{

    string responseContent;

    var memStream = new MemoryStream();

    var webRequest = (HttpWebRequest)WebRequest.Create(url);

    // 邊界符

    var boundary = "---------------" + DateTime.Now.Ticks.ToString("x");

    // 邊界符

    var beginBoundary = Encoding.ASCII.GetBytes("--" + boundary + "\r\n");

    // 最后的結(jié)束符

    var endBoundary = Encoding.ASCII.GetBytes("--" + boundary + "--\r\n");

    // 設(shè)置屬性

    webRequest.Method = "POST";

    webRequest.Timeout = timeOut;

    webRequest.ContentType = "multipart/form-data; boundary=" + boundary;

    //寫入開始邊界符

    memStream.Write(beginBoundary, 0, beginBoundary.Length);

    // 寫入文件

    const string filePartHeader =

        "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\n" +

         "Content-Type: application/octet-stream\r\n\r\n";

    var header = string.Format(filePartHeader, fileKeyName, "card.jpg");

    var headerbytes = Encoding.UTF8.GetBytes(header);

    memStream.Write(headerbytes, 0, headerbytes.Length);

    file.CopyTo(memStream);

    // 寫入字符串的Key

    var stringKeyHeader = "\r\n--" + boundary +

                           "\r\nContent-Disposition: form-data; name=\"{0}\"" +

                           "\r\n\r\n{1}\r\n";

    foreach (byte[] formitembytes in from string key in stringDict.Keys

                                     select string.Format(stringKeyHeader, key, stringDict[key])

                                         into formitem

                                         select Encoding.UTF8.GetBytes(formitem))

    {

        memStream.Write(formitembytes, 0, formitembytes.Length);

    }

    // 寫入最后的結(jié)束邊界符

    memStream.Write(endBoundary, 0, endBoundary.Length);

    webRequest.ContentLength = memStream.Length;

    // 構(gòu)造完畢，執(zhí)行POST方法

    var requestStream = webRequest.GetRequestStream();

    memStream.Position = 0;

    var tempBuffer = new byte[memStream.Length];

    memStream.Read(tempBuffer, 0, tempBuffer.Length);

    memStream.Close();

    requestStream.Write(tempBuffer, 0, tempBuffer.Length);

    requestStream.Close();

    var httpWebResponse = (HttpWebResponse)webRequest.GetResponse();

    using (var httpStreamReader = new StreamReader(httpWebResponse.GetResponseStream(),

                                                    Encoding.GetEncoding("utf-8")))

    {

        responseContent = httpStreamReader.ReadToEnd();

    }

    httpWebResponse.Close();

    webRequest.Abort();

    return responseContent;

}

二、EmguCV類庫調(diào)用

環(huán)境搭建

下載地址：EmguCV官網(wǎng)

在File類別下下載這個(gè)EXE，進(jìn)行安裝，安裝后在目錄下能找相應(yīng)組件，還有些應(yīng)用的案例。

C#進(jìn)行識別，需進(jìn)行圖片二值化處理和OCR調(diào)用相關(guān)DLL可在我整理的地址下載：360云盤 提取碼：89f4
dll文件夾中的dll引用到C#項(xiàng)目中，x64，x86，tessdata對應(yīng)OCR識別的類庫和語言庫，我tessdata中已添加中文語言包，將這三個(gè)文件夾放入程序執(zhí)行文件夾中。

Demo

自己做的小Demo如圖：身份證圖片是百度上下載的

相關(guān)代碼如下：

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

using Emgu.CV;

using Emgu.CV.OCR;

using Emgu.CV.Structure;

using System.IO;

namespace ImageManage

{

    public partial class Form1 : Form

    {

        Image imageThreshold;

        public Form1()

        {

            InitializeComponent();

        }

        private void btn_convert_Click(object sender, EventArgs e)

        {

            //第一個(gè)參數(shù)是語言包文件夾的地址，不寫默認(rèn)在執(zhí)行文件夾下

            Tesseract _ocr = new Tesseract("", "chi_sim", OcrEngineMode.TesseractOnly);

            _ocr.Recognize(imageThreshold);

            String text = _ocr.GetText();

            this.textBox1.Text = text;

        }

        private void pictureBox1_Click(object sender, EventArgs e)

        {

            OpenFileDialog of = new OpenFileDialog();

            of.Title = "請選擇圖片";

            if (of.ShowDialog() == DialogResult.OK)

            {

                string file = of.FileName;

                Image img = Image.FromFile(file);

                pictureBox1.Image = img;            

            }

            Bitmap bitmap = (Bitmap)this.pictureBox1.Image;

            Image imageSource = new Imagebyte>(bitmap);

            Image imageGrayscale = imageSource.Convert();

            imageGrayscale = randon(imageGrayscale);

            imageThreshold = imageGrayscale.ThresholdBinary(new Gray(100), new Gray(255));

            this.pictureBox2.Image = imageThreshold.ToBitmap();

        }

        /// 

        /// 旋轉(zhuǎn)校正

        /// 

        /// 

        /// 

        private Image randon(Image imageInput)//圖像投影旋轉(zhuǎn)法傾斜校正子函數(shù)定義

        {

            int nwidth = imageInput.Width;

            int nheight = imageInput.Height;

            int sum;

            int SumOfCha;

            int SumOfChatemp = 0;

            int[] sumhang = new int[nheight];

            Image resultImage = imageInput;

            Image ImrotaImage;

            //20度范圍內(nèi)的調(diào)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;

        }

    }

}

三、Office 2007組件

該組件免費(fèi)而且識別度比較高。

環(huán)境搭建

Office 2007組件MODI，需要安裝Ofiice2007，且由于兼容性需要安裝補(bǔ)丁，SP1或者SP2都行，補(bǔ)丁下載地址如下：
SP1下載地址 SP2下載地址

安裝后控制面板-->卸載或更新程序-->選擇Office2007-->選擇更改-->選擇添加或修復(fù)功能-->彈出下面界面，運(yùn)行相應(yīng)組件。

將Office工具-->Microsoft Office Document Imaging 下的工具運(yùn)行

在C#項(xiàng)目中引用Com組件即可：

如果Office組件應(yīng)用不是在本地程序而需要部署在IIS上，還需將應(yīng)用程序的應(yīng)用池的權(quán)限設(shè)置為如下圖所示：程序應(yīng)用池-->高級設(shè)置-->標(biāo)識

Demo