spdis
141 lines
4.0 KiB
C++
141 lines
4.0 KiB
C++
/*
|
||
* @Author: ilikara 3435193369@qq.com
|
||
* @Date: 2025-01-07 06:26:01
|
||
* @LastEditors: ilikara 3435193369@qq.com
|
||
* @LastEditTime: 2025-01-07 08:10:45
|
||
* @FilePath: /smartcar/opencv_demo2/opencv_demo2.cpp
|
||
* @Description: 使用Haar级联分类器从USB摄像头获取图像，并将图像居中显示到160x128的RGB565 framebuffer设备
|
||
*/
|
||
#include <opencv2/opencv.hpp>
|
||
#include <fcntl.h>
|
||
#include <unistd.h>
|
||
#include <sys/mman.h>
|
||
#include <linux/fb.h>
|
||
#include <sys/ioctl.h>
|
||
|
||
using namespace cv;
|
||
using namespace std;
|
||
|
||
// 将 RGB888 转换为 RGB565
|
||
ushort rgb888_to_rgb565(const Vec3b &color)
|
||
{
|
||
return ((color[2] >> 3) << 11) | ((color[1] >> 2) << 5) | (color[0] >> 3);
|
||
}
|
||
|
||
int main()
|
||
{
|
||
// Framebuffer 设备
|
||
const char *fb_device = "/dev/fb0";
|
||
int fb_fd = open(fb_device, O_RDWR);
|
||
if (fb_fd == -1)
|
||
{
|
||
cerr << "Error: Cannot open framebuffer device" << endl;
|
||
return -1;
|
||
}
|
||
|
||
// 获取 Framebuffer 信息
|
||
struct fb_var_screeninfo vinfo;
|
||
if (ioctl(fb_fd, FBIOGET_VSCREENINFO, &vinfo))
|
||
{
|
||
cerr << "Error: Cannot get framebuffer information" << endl;
|
||
close(fb_fd);
|
||
return -1;
|
||
}
|
||
|
||
// 检查 Framebuffer 是否支持 RGB565
|
||
if (vinfo.bits_per_pixel != 16)
|
||
{
|
||
cerr << "Error: Framebuffer is not RGB565 format" << endl;
|
||
close(fb_fd);
|
||
return -1;
|
||
}
|
||
|
||
// 映射 Framebuffer 到内存
|
||
size_t fb_size = vinfo.xres * vinfo.yres * vinfo.bits_per_pixel / 8;
|
||
ushort *fb_data = (ushort *)mmap(0, fb_size, PROT_READ | PROT_WRITE, MAP_SHARED, fb_fd, 0);
|
||
if (fb_data == MAP_FAILED)
|
||
{
|
||
cerr << "Error: Failed to map framebuffer to memory" << endl;
|
||
close(fb_fd);
|
||
return -1;
|
||
}
|
||
|
||
// 打开USB摄像头
|
||
VideoCapture cap(0); // 0表示第一个摄像头
|
||
if (!cap.isOpened())
|
||
{
|
||
cerr << "Error: Cannot open camera" << endl;
|
||
return -1;
|
||
}
|
||
|
||
// 设置摄像头参数
|
||
cap.set(CAP_PROP_FRAME_WIDTH, 640);
|
||
cap.set(CAP_PROP_FRAME_HEIGHT, 360);
|
||
cap.set(CAP_PROP_FOURCC, VideoWriter::fourcc('M', 'J', 'P', 'G'));
|
||
cap.set(CAP_PROP_AUTO_EXPOSURE, -1); // 启用自动曝光
|
||
|
||
// 加载Haar级联分类器
|
||
CascadeClassifier face_cascade;
|
||
if (!face_cascade.load("opencv/share/opencv4/haarcascades/haarcascade_frontalface_default.xml"))
|
||
{
|
||
cerr << "Error: Cannot load Haar cascade classifier" << endl;
|
||
return -1;
|
||
}
|
||
|
||
// 创建 OpenCV 图像（160x128，RGB888）
|
||
Mat image(128, 160, CV_8UC3, Scalar(0, 0, 0));
|
||
|
||
while (true)
|
||
{
|
||
Mat frame;
|
||
cap >> frame; // 从摄像头获取一帧图像
|
||
if (frame.empty())
|
||
{
|
||
cerr << "Error: Cannot grab frame from camera" << endl;
|
||
break;
|
||
}
|
||
|
||
// 缩放图像到160x90
|
||
Mat resized_frame;
|
||
resize(frame, resized_frame, Size(160, 90));
|
||
|
||
// 转换为灰度图像
|
||
Mat gray;
|
||
cvtColor(resized_frame, gray, COLOR_BGR2GRAY);
|
||
|
||
// 使用Haar级联分类器检测人脸
|
||
vector<Rect> faces;
|
||
face_cascade.detectMultiScale(gray, faces, 1.1, 2, 0 | CASCADE_SCALE_IMAGE, Size(30, 30));
|
||
|
||
// 在图像上绘制检测到的人脸
|
||
for (const auto &face : faces)
|
||
{
|
||
rectangle(resized_frame, face, Scalar(255, 0, 0), 2);
|
||
}
|
||
|
||
// 将图像居中显示到160x128的framebuffer
|
||
image.setTo(Scalar(0, 0, 0)); // 清空图像
|
||
int y_offset = (128 - 90) / 2;
|
||
resized_frame.copyTo(image(Rect(0, y_offset, 160, 90)));
|
||
|
||
// 将 OpenCV 图像（RGB888）转换为 RGB565 并写入 Framebuffer
|
||
for (int y = 0; y < image.rows; y++)
|
||
{
|
||
for (int x = 0; x < image.cols; x++)
|
||
{
|
||
Vec3b color = image.at<Vec3b>(y, x);
|
||
fb_data[y * vinfo.xres + x] = rgb888_to_rgb565(color);
|
||
}
|
||
}
|
||
|
||
// 等待一段时间
|
||
usleep(33333);
|
||
}
|
||
|
||
// 释放资源
|
||
munmap(fb_data, fb_size);
|
||
close(fb_fd);
|
||
cap.release();
|
||
|
||
return 0;
|
||
} |