Linux免驱相机控制C++，读取图像并转换为opencv Mat格式 同时设置相机曝光 白平衡 增益 gamma 锐度 色调

#include "imagecamera.h" #include <string.h> #include <unistd.h> #include <fcntl.h> #include <errno.h> #include <sys/ioctl.h> #include <sys/time.h> #include <sys/mman.h> #include <linux/videodev2.h> #include <QDir> #include <dirent.h> #include <unistd.h> #include <asm/types.h> #include <math.h> #include <malloc.h> #include <QImage> #include <QDebug> #include "opencv2/imgcodecs.hpp" #include <iostream> std::string ImageCamera::get_device_info(const char* dev_name) { int fd = open(dev_name, O_RDWR); if (fd == -1) { perror("Failed to open device"); return std::string(); } struct v4l2_capability cap; if (ioctl(fd, VIDIOC_QUERYCAP, &cap) == -1) { perror("VIDIOC_QUERYCAP failed"); close(fd); return std::string(); } std::cout << "Device: " << dev_name << "\n"; std::cout << "Driver: " << cap.driver << "\n"; std::cout << "Card: " << cap.card << "\n"; std::cout << "Bus Info: " << cap.bus_info << "\n"; std::cout << "Version: " << cap.version << "\n"; std::cout << "Capabilities: 0x" << std::hex << cap.capabilities << "\n"; close(fd); return std::string((const char*)cap.card); } std::map<std::string,std::string> ImageCamera::listCameras() { DIR *dir; struct dirent *ent; std::map<std::string,std::string> l_card_device;//key:card value:device if ((dir = opendir("/dev"))) { while ((ent = readdir(dir)) != NULL) { if (strncmp(ent->d_name, "video", 5) == 0) { std::string dev_name = "/dev/"; dev_name += ent->d_name; auto l_card=get_device_info(dev_name.c_str()); l_card_device[l_card]=dev_name; } } closedir(dir); } else { perror("Failed to open /dev directory"); return l_card_device; } return l_card_device; } ImageCamera::ImageCamera(QString c, QObject *parent) :QObject(parent) { camera = c; err.clear(); memset(pix_format, 0, sizeof(pix_format)); cam_fd = -1; buffer_count = 1; //5; // count 指定根据图像占用空间大小申请的缓存区个数 video_buffer_ptr = new u8*[buffer_count]; } ImageCamera::~ImageCamera() { if(video_buffer_ptr!=nullptr) delete video_buffer_ptr; } bool ImageCamera::OpenCamera(const int width,const int height) { nWidth = width; nHeight = height; nSize = nWidth * nHeight * 2; int index = 0; int ret = 0; if(camera.isEmpty()) { err = QString("设备节点位置为空"); return false; } if(cam_fd != -1) { close(cam_fd); } // 打开相机设备节点 cam_fd = open(camera.toStdString().c_str(), O_RDWR); if(cam_fd == -1) { err = QString("打开相机节点失败"); return false; } // 设置使用的相机通道，此处为0 if(0 != ioctl(cam_fd, VIDIOC_S_INPUT, &index)) { err = QString("%1").arg(strerror(errno)); close(cam_fd); cam_fd=-1; return false; } // 查询相机的基本信息 struct v4l2_capability cap; ioctl(cam_fd, VIDIOC_QUERYCAP, &cap); qDebug("Driver Name:%s, Card Name:%s, Bus info:%s, Driver Version:%u.%u.%u", cap.driver,cap.card,cap.bus_info,(cap.version>>16)&0xFF, (cap.version>>8)&0xFF,cap.version&0xFF); // 查询相机支持的采图格式 struct v4l2_fmtdesc fmtdesc; fmtdesc.index=0; fmtdesc.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; qDebug("Support format:"); do{ ret=ioctl(cam_fd, VIDIOC_ENUM_FMT, &fmtdesc); qDebug("index %d, format %s", fmtdesc.index, fmtdesc.description); fmtdesc.index++; }while(0==ret); // 查询相机支持的帧率范围 struct v4l2_streamparm stream_parm; memset(&stream_parm, 0, sizeof(struct v4l2_streamparm)); stream_parm.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; ret = ioctl(cam_fd, VIDIOC_G_PARM, &stream_parm); qDebug("FrameRate: numerator = %d, denominator = %d", stream_parm.parm.capture.timeperframe.numerator, stream_parm.parm.capture.timeperframe.denominator); // 设置相机的输出格式，图片大小等数据 struct v4l2_format format; memset(&format, 0, sizeof(format)); format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; format.fmt.pix.pixelformat = V4L2_PIX_FMT_MJPEG; // 设置相机输出为JPEG(V4L2_PIX_FMT_MJPEG)，也可设置为yuyv(V4L2_PIX_FMT_YUYV)， format.fmt.pix.width = nWidth; // 设置输出图片宽、高 format.fmt.pix.height = nHeight; // 尝试相机是否支持改格式 ret = ioctl(cam_fd, VIDIOC_TRY_FMT, &format); if (ret != 0) { err = QString::asprintf("ioctl(VIDIOC_TRY_FMT) failed %d(%s)", errno, strerror(errno)); qDebug(err.toLatin1().constData()); close(cam_fd); cam_fd=-1; return false; } // 真正进行设置改格式 format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; ret = ioctl(cam_fd, VIDIOC_S_FMT, &format); if (ret != 0) { err = QString::asprintf("ioctl(VIDIOC_S_FMT) failed %d(%s)", errno, strerror(errno)); qDebug(err.toLatin1().constData()); close(cam_fd); cam_fd=-1; return false; } // 获取相机输出的图片参数 if(-1 == ioctl(cam_fd, VIDIOC_G_FMT, &format)){ // 得到图片格式 err = QString("set format failed!"); qDebug(err.toLatin1().constData()); close(cam_fd); cam_fd=-1; return false; } qDebug("fmt.type:\t\t%d",format.type); /**************************************************************/ // 此处的图片格式，决定着采集到的图片数据要怎么解析，一般分为 MJPG 和 YUYV，上面设置的和此处获取的在某些情况下会不一致，因此需要此处决定解析格式 sprintf(pix_format, "%c%c%c%c", \ format.fmt.pix.pixelformat & 0xFF,\ (format.fmt.pix.pixelformat >> 8) & 0xFF, \ (format.fmt.pix.pixelformat >> 16) & 0xFF,\ (format.fmt.pix.pixelformat >> 24) & 0xFF); qDebug("pix.pixelformat:\t%s", pix_format); qDebug("pix.width:\t\t%d",format.fmt.pix.width); qDebug("pix.height:\t\t%d",format.fmt.pix.height); qDebug("pix.field:\t\t%d",format.fmt.pix.field); // 查询相机需要开辟的内存信息 // 向驱动申请视频流数据的帧缓冲区 struct v4l2_requestbuffers req; req.count = buffer_count; req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; req.memory = V4L2_MEMORY_MMAP; ret = ioctl(cam_fd, VIDIOC_REQBUFS, &req); // 申请若干个帧缓冲区 if (ret != 0) { err = QString::asprintf("ioctl(VIDIOC_REQBUFS) failed %d(%s)", errno, strerror(errno)); qDebug(err.toLatin1().constData()); close(cam_fd); cam_fd=-1; return false; } qDebug("req.count: %d", req.count); if (req.count < buffer_count) { err = QString::asprintf("request buffer failed"); qDebug(err.toLatin1().constData()); close(cam_fd); cam_fd=-1; return false; } // 逐一将相机开辟的内存进行内存映射 // 应用程序通过内存映射，将帧缓冲区的地址映射到用户空间 struct v4l2_buffer buffer; memset(&buffer, 0, sizeof(buffer)); buffer.type = req.type; buffer.memory = V4L2_MEMORY_MMAP; for (int i=0; i<req.count; i++) { buffer.index = i; ret = ioctl (cam_fd, VIDIOC_QUERYBUF, &buffer); // 查询帧缓冲区的内核空间中的长度和偏移量 if (ret != 0) { err = QString::asprintf("ioctl(VIDIOC_QUERYBUF) failed %d(%s)", errno, strerror(errno)); qDebug(err.toLatin1().constData()); return false; } qDebug("buffer.length: %d", buffer.length); qDebug("buffer.m.offset: %d", buffer.m.offse