ElfBoard開源項目|車牌識別項目技術(shù)文檔

#include <stdio.h>
#include <iostream>
#include <string.h>
#include <curl/curl.h>
#include <json/json.h>
#include <fstream>
#include <memory>
#include <cstdlib>
#include <regex>
#include <string>
#include <unistd.h>
 

inline size_t onWriteData(void * buffer, size_t size, size_t nmemb, void * userp)
{
    std::string * str = dynamic_cast<std::string *>((std::string *)userp);
    str->append((char *)buffer, size * nmemb);
    return nmemb;
}

std::string getFileBase64Content(const char * path,  bool urlencoded=false)
{
    const std::string base64_chars =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    "abcdefghijklmnopqrstuvwxyz"
    "0123456789+/";
    std::string ret;
    int i = 0;
    int j = 0;
    unsigned char char_array_3[3];
    unsigned char char_array_4[4];
    unsigned int bufferSize = 1024;
    unsigned char buffer[bufferSize];
    std::ifstream file_read;
    file_read.open(path, std::ios::binary);
 
    while (!file_read.eof()){
 
        file_read.read((char *) buffer, bufferSize * sizeof(char));
        int num = file_read.gcount();
        int m = 0;
        while (num--){
 
            char_array_3[i++] = buffer[m++];
            if(i == 3){
                char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
                char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
                char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
                char_array_4[3] = char_array_3[2] & 0x3f;
 
                for(i = 0; (i <4) ; i++)
                    ret += base64_chars[char_array_4[i]];
                i = 0;
            }
        }
    }
    file_read.close();
    if(i){
 
        for(j = i; j < 3; j++)
            char_array_3[j] = '';
 
        char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
        char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
        char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
        char_array_4[3] = char_array_3[2] & 0x3f;
 
        for(j = 0; (j < i + 1); j++)
            ret += base64_chars[char_array_4[j]];
 
        while((i++ < 3))
            ret += '=';
    }
    if (urlencoded)
        ret = curl_escape(ret.c_str(), ret.length());
 
    return ret;
}
std::string performCurlRequest(const char *pic_path, const std::string &token) {
    std::string result;
    char *web_curl = nullptr;
    CURL *curl = curl_easy_init();
    CURLcode res;
    if (!asprintf(&web_curl, "https://aip.baidubce.com/rest/2.0/ocr/v1/license_plate?access_token=%s", token.c_str())) {
        perror("asprintf error");
    }
 
        curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "POST");
        curl_easy_setopt(curl, CURLOPT_URL, web_curl);
        curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
        curl_easy_setopt(curl, CURLOPT_DEFAULT_PROTOCOL, "https");

        curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
        curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);

        struct curl_slist *headers = NULL;
        headers = curl_slist_append(headers, "Content-Type: application/x-www-form-urlencoded");
        headers = curl_slist_append(headers, "Accept: application/json");
        curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
 
        std::string base64_image = getFileBase64Content(pic_path, true);
        std::string post_data = "image=" + base64_image + "&multi_detect=false&multi_scale=false";
 
        curl_easy_setopt(curl, CURLOPT_POSTFIELDS, post_data.c_str());
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &result);
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, onWriteData);

        curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, false);
         curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
        
        if(curl_easy_perform(curl) != CURLE_OK)
            fprintf(stderr, "Curl request failed: %sn", curl_easy_strerror(res));
 
    curl_easy_cleanup(curl);
    free(web_curl);
    return result;
}
int main(int argc, char *argv[]) {
    
  std::string access_token = "24.d69c300e601a1d2e3f735d916d45eb5a.2592000.1724636199.282335-99367601";  //填自己的access_tocken
    std::string result;
  std::string car_number;

        result = performCurlRequest("/home/root/num/1.jpg", access_token); //存放圖片的路徑

        std::string json = result;
        std::regex pattern(""number":"(.*?)"");
        std::smatch match;
        if (std::regex_search(json, match, pattern)) {
                car_number = match[1].str();
                std::cout << "read car number is: " << car_number << std::endl;
  }
}

bbs.elfboard.com/forum.php?mod=viewthread&tid=495&extra=page%3D1

bbs.elfboard.com/forum.php?mod=viewthread&tid=497&extra=page%3D1

bbs.elfboard.com/forum.php?mod=viewthread&tid=498&extra=page%3D1

應(yīng)用編譯

elf@ubuntu:~/work$  . /opt/fsl-imx-x11/4.1.15-2.0.0/environment-setup-cortexa7hf-neon-poky-linux-gnueabi 
elf@ubuntu:~/work$  $CXX demoCar.cpp -o demoCar -I /home/elf/work/curl-7.71.1/install/include/ -I /home/elf/work/jsoncpp-1.9.5/install/include/ -I /home/elf/work/opencv-3.4.1/install/include/ -std=c++11 -L /home/elf/work/curl-7.71.1/install/lib/ -L /home/elf/work/jsoncpp-1.9.5/install/lib/ -L /home/elf/work/opencv-3.4.1/install/lib/ -lopencv_core -lopencv_highgui -lopencv_imgproc -lopencv_videoio -lopencv_imgcodecs -lcurl

int main(int argc, char *argv[])  
{  
    QApplication a(argc, argv);  
    Camera w;  
    w.setWindowFlags(w.windowFlags()& ~Qt::WindowMaximizeButtonHint& ~Qt::WindowMinimizeButtonHint );  
    w.showMaximized();  
    w.show();  
    return a.exec();  
}  

ui->setupUi(this);  
  
     timer = new QTimer;  
     QDesktopWidget* desktopWidget = QApplication::desktop();  
     QRect screenRect = desktopWidget->screenGeometry();  
  
     qDebug("screen.width = %d , screen.height = %d",screenRect.width(),screenRect.height());  
  
     this->imageWidget = new ImageWidget(this);  
     this->imageWidget->setBackgroundRole(QPalette::Dark);  
     this->imageWidget->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);  
     this->imageWidget->setObjectName(QString::fromUtf8("imageWidget"));  
  
     if(screenRect.width()==800)  
     {  
       ui->pbt_start->setGeometry(60,300,70,50);  
       ui->pbt_stop->setGeometry(190,300,70,50);  
       this->imageWidget->setGeometry(QRect(5, 30, 350, 250));  
     }  
     else if(screenRect.width()>800)  
     {  
         ui->pbt_start->setGeometry(80,400,70,70);  
         ui->pbt_stop->setGeometry(260,400,70,70);  
         this->imageWidget->setGeometry(QRect(6, 37, 500, 330));  
     }  

void deviceOpen(void)  
{  
       fd = open(deviceName, O_RDWR | O_NONBLOCK, 0);  
  
       if (-1 == fd)  
       {  
            QMessageBox::about(NULL, "About", "camera open error");  
            exit(EXIT_FAILURE);  
       }  
}   

初始化攝像頭設(shè)備

void deviceInit(void)  
{  
    struct v4l2_capability cap;  
    struct v4l2_cropcap cropcap;  
    struct v4l2_crop crop;  
    struct v4l2_format fmt;  
    struct v4l2_streamparm sparm;  
    unsigned int min;  
     if (-1 == xioctl(fd, VIDIOC_QUERYCAP, &cap))  
     {  
            if (EINVAL == errno)  
            {  
                 QMessageBox::about(NULL,"Information"," no V4L2 device");  
                 exit(EXIT_FAILURE);  
            }  
           else  
            {  
                 errno_exit("VIDIOC_QUERYCAP");  
            }  
      }  
      if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE))  
      {  
             QMessageBox::about(NULL,"Information"," no video capture device");  
             exit(EXIT_FAILURE);  
      }  
      struct v4l2_input input;  
      input.index = 0;  
      if ( ioctl(fd, VIDIOC_ENUMINPUT, &input) != 0)  
      {  
            QMessageBox::about(NULL,"Information","set input error");  
            exit(0);  
      }  
      if ((ioctl(fd, VIDIOC_S_INPUT, &input)) < 0)  
      {  
            QMessageBox::about(NULL,"Information","set s_input error");  
             exit(0);  
       }  
       CLEAR(cropcap);  
       cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;  
      if (0 == xioctl(fd, VIDIOC_CROPCAP, &cropcap))  
      {  
           crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;  
           crop.c.top = 0;  
           crop.c.left = 0;  
           crop.c.height = 720;  
           crop.c.width = 1280;  
           if (-1 == xioctl(fd, VIDIOC_S_CROP, &crop))  
           {  
                switch (errno)  
                {  
                     case EINVAL:  
                          break;  
                     default:  
                        break;  
                }  
            }  
       }  
      CLEAR (fmt);  
       // v4l2_format  
       fmt.type                = V4L2_BUF_TYPE_VIDEO_CAPTURE;  
       fmt.fmt.pix.width       = width;  
       fmt.fmt.pix.height      = height;  
       fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;  
       fmt.fmt.pix.field       = V4L2_FIELD_ANY;  
      if (-1 == xioctl(fd, VIDIOC_S_FMT, &fmt))  
          errno_exit("VIDIOC_S_FMT");  
      /* Note VIDIOC_S_FMT may change width and height.*/  
      if (width != fmt.fmt.pix.width)  
      {  
           width = fmt.fmt.pix.width;  
          //fprintf(stderr,"Image width set to %i by device %s.n",width,deviceName);  
       }  
      if (height != fmt.fmt.pix.height)  
      {  
           height = fmt.fmt.pix.height;  
           //fprintf(stderr,"Image height set to %i by device %s.n",height,deviceName);  
      }  
      /*Buggy driver paranoia. */  
      min = fmt.fmt.pix.width * 2;  
      if (fmt.fmt.pix.bytesperline < min)  
         fmt.fmt.pix.bytesperline = min;  
       min = fmt.fmt.pix.bytesperline * fmt.fmt.pix.height;  
      if (fmt.fmt.pix.sizeimage < min)  
          fmt.fmt.pix.sizeimage = min;  
      CLEAR (sparm);  
          sparm.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;  
          sparm.parm.capture.capturemode = 0;  
          sparm.parm.capture.timeperframe.numerator = 1;  
          sparm.parm.capture.timeperframe.denominator = 30;  
          if(xioctl(fd,VIDIOC_S_PARM,&sparm) < 0){  
                  errno_exit("cam s parm");  
                 // exit(1);  
          }  
       mmapInit();  
}  

void captureStart(void)  
{  
        unsigned int i;  
        enum v4l2_buf_type type;  
  
        for (i = 0; i < n_buffers; ++i)  
        {  
                struct v4l2_buffer buf;  
  
                CLEAR (buf);  
                buf.type        = V4L2_BUF_TYPE_VIDEO_CAPTURE;  
                buf.memory      = V4L2_MEMORY_MMAP;  
                buf.index       = i;  
  
                if (-1 == xioctl(fd, VIDIOC_QBUF, &buf))  
                        errno_exit("VIDIOC_QBUF");  
        }  
  
        type = V4L2_BUF_TYPE_VIDEO_CAPTURE;  
  
        if (-1 == xioctl(fd, VIDIOC_STREAMON, &type))  
           errno_exit("VIDIOC_STREAMON");  
}  

void Camera::up_date()  
{  
    unsigned char image_buf[921600+54];  
    frameRead(image_buf);  
    this->imageWidget->setPixmap(image_buf);  
}  

應(yīng)用編譯及測試

編譯

elf@ubuntu:~/work/camera-demo$ . /opt/fsl-imx-x11/4.1.15-2.0.0/environment-setup-cortexa7hf-neon-poky-linux-gnueabi 
elf@ubuntu:~/work/camera-demo$ qmake
elf@ubuntu:~/work/camera-demo$ make

root@ELF1:~# cp /run/media/sda1/camera-demo ./
root@ELF1:~# chmod 777 camera-demo
root@ELF1:~# export DISPLAY=:0.0
root@ELF1:~# ./camera-demo

在這里就可以和前面車牌識別結(jié)合起來了，比如攝像頭里面的畫面是一張車牌信息，通過截取攝像頭中的實時畫面到本地，然后上傳到百度智能云的后臺進(jìn)行識別，至此就完成了通過攝像頭進(jìn)行車牌識別的過程。

?

項目測試

root@ELF1:~# elf1_cmd_wifi.sh -i 8723 -s 賬號 -p 密碼

執(zhí)行應(yīng)用

root@ELF1:~# ./camera-demo &
root@ELF1:~# ./demoCar

單擊“start”按鈕，識別結(jié)果如下圖所示