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C实现身份证识别功能的代码详解

更新时间：2023-11-13

段落一：引言

随着身份证普及率的提高，身份证已成为证明个人身份的重要证件，为了提高工作效率，很多地方都提出了身份证自动化识别的要求。本文将介绍如何使用C#语言实现身份证识别的功能。

段落二：身份证识别的基本原理

身份证识别可以通过读取身份证上的身份证号、姓名、性别、出生日期等信息进行实现。在C#中，我们可以使用WIN32 API函数来读取身份证信息。代码如下：

[DllImport("OcrIdCard.dll")]
public static extern IntPtr ScanIdCard(string strPathFile, QUERY_IDCARDINFO_STRUCT pQueryIdCardInfoStruct);

[DllImport("OcrIdCard.dll")]
public static extern void UnInitialize();

其中，ScanIdCard函数的第一个参数为身份证保存的路径,第二个参数为要返回的身份证信息的结构体QUERY_IDCARDINFO_STRUCT。QUERY_IDCARDINFO_STRUCT的定义如下：

[StructLayoutAttribute(LayoutKind.Sequential, CharSet = CharSet.Unicode, Pack = 1)]
public struct QUERY_IDCARDINFO_STRUCT
{
    //姓名
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 16)] 
    public string g_szName;

    //性别
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 3)]
    public string g_szSex;

    //民族
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 16)]
    public string g_szNation;

    //出生日期
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 16)]
    public string g_szBirth;

    //住址
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 64)]
    public string g_szAddress;

    //身份证号码
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 19)]
    public string g_szIdNum;

    //发证单位
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 64)]
    public string g_szDepartment;

    //有效期开始日期
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 16)]
    public string g_szStartDate;

    //有效期终止日期
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 16)]
    public string g_szEndDate;
}

段落三：身份证识别的实现

在C#中，我们可以将获取身份证上的信息需要的函数封装成一个类，便于调用。如下所示：

public class IdCardRecognition
{
    [StructLayoutAttribute(LayoutKind.Sequential, CharSet = CharSet.Unicode, Pack = 1)]
    public struct QUERY_IDCARDINFO_STRUCT
    {
        //姓名
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 16)]
        public string g_szName;

        //性别
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 3)]
        public string g_szSex;

        //民族
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 16)]
        public string g_szNation;

        //出生日期
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 16)]
        public string g_szBirth;

        //住址
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 64)]
        public string g_szAddress;

        //身份证号码
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 19)]
        public string g_szIdNum;

        //发证单位
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 64)]
        public string g_szDepartment;

        //有效期开始日期
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 16)]
        public string g_szStartDate;

        //有效期终止日期
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 16)]
        public string g_szEndDate;
    }

    [DllImport("OcrIdCard.dll")]
    public static extern IntPtr ScanIdCard(string strPathFile, QUERY_IDCARDINFO_STRUCT pQueryIdCardInfoStruct);
    [DllImport("OcrIdCard.dll")]
    public static extern void UnInitialize();

    public static string[] ReadIdCardInfo(string path)
    {
        QUERY_IDCARDINFO_STRUCT infos = new QUERY_IDCARDINFO_STRUCT();
        IntPtr pInfos = Marshal.AllocHGlobal(256);  //开辟256字节的内存
        Marshal.StructureToPtr(infos, pInfos, false); 

        ScanIdCard(path, infos);

        infos = (QUERY_IDCARDINFO_STRUCT)Marshal.PtrToStructure(pInfos, typeof(QUERY_IDCARDINFO_STRUCT));
        Marshal.FreeHGlobal(pInfos);

        string[] data = new string[9];
        data[0] = infos.g_szName;
        data[1] = infos.g_szSex;
        data[2] = infos.g_szNation;
        data[3] = infos.g_szBirth;
        data[4] = infos.g_szAddress;
        data[5] = infos.g_szIdNum;
        data[6] = infos.g_szDepartment;
        data[7] = infos.g_szStartDate;
        data[8] = infos.g_szEndDate;

        UnInitialize();
        return data;
    }
}

段落四：身份证识别的使用方法

通过上述封装好的IdCardRecognition类，我们可以很方便地调用身份证识别功能。具体使用方法如下：

private void buttonTest_Click(object sender, EventArgs e)
{
    OpenFileDialog openFileDialog = new OpenFileDialog();
    openFileDialog.Filter = "JPEG files(*.jpg)|*.jpg|BMP files(*.bmp)|*.bmp|All files(*.*)|*.*";

    if (openFileDialog.ShowDialog() != DialogResult.OK)
    {
        return;
    }

    string path = openFileDialog.FileName;
    string[] msg = IdCardRecognition.ReadIdCardInfo(path);

    textBoxName.Text = msg[0];
    textBoxSex.Text = msg[1];
    textBoxNation.Text = msg[2];
    textBoxBirth.Text = msg[3];
    textBoxAddress.Text = msg[4];
    textBoxIdNum.Text = msg[5];
    textBoxDepartment.Text = msg[6];
    textBoxStartPeriod.Text = msg[7];
    textBoxEndPeriod.Text = msg[8];

}

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