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本文档展示了如何使用 OpenCV 进行图像处理和特征检测,包括边缘检测、直线检测、圆检测以及多边形拟合。通过这些技术,可以实现对摄像头捕获的实时视频流进行分析,并标记出检测到的特征。
源代码地址:https://gitee.com/LockzhinerAI/LockzhinerVisionModule/tree/master/Cpp_example/C04_find_contours
#include <opencv2/opencv.hpp>
cv::GaussianBlur(src, dst, Size(3, 3), 0);
cv::Canny(src, dst, 50, 150);
cv::findContours(src, contours, hierarchy, mode, method);
cv::approxPolyDP(contours[i], approx, epsilon, closed);
cv::HoughLinesP(src, lines, 1, CV_PI / 180, 50, 50, 10);
cv::HoughCircles(src, circles, CV_HOUGH_GRADIENT, 1, src.rows / 8, 200, 100, 0, 0);
cv::cvtColor(src, gray, cv::COLOR_BGR2GRAY);
cv::GaussianBlur(gray, gray, cv::Size(5, 5), 0);
std::vector<cv::Vec3f> circles;
cv::HoughCircles(gray, circles, cv::HOUGH_GRADIENT, 1, gray.rows / 16, 100, 30, 1, 300);
for (const cv::Vec3f &circle : circles) {
cv::Point center(cvRound(circle[0]), cvRound(circle[1]));
int radius = cvRound(circle[2]);
cv::circle(src, center, radius, cv::Scalar(0, 255, 255), 2); // 绘制圆
}
#include <lockzhiner_vision_module/edit/edit.h>
#include <opencv2/opencv.hpp>
#include <iostream>
int main()
{
lockzhiner_vision_module::edit::Edit edit;
if (!edit.StartAndAcceptConnection())
{
std::cerr << "Error: Failed to start and accept connection." << std::endl;
return EXIT_FAILURE;
}
std::cout << "Device connected successfully." << std::endl;
// 初始化摄像头
cv::VideoCapture cap;
int width = 640; // 设置摄像头分辨率宽度
int height = 480; // 设置摄像头分辨率高度
cap.set(cv::CAP_PROP_FRAME_WIDTH, width);
cap.set(cv::CAP_PROP_FRAME_HEIGHT, height);
cap.open(0); // 参数 0 表示默认摄像头设备
if (!cap.isOpened())
{
std::cerr << "Error: Could not open camera." << std::endl;
return EXIT_FAILURE;
}
while (true)
{
// 读取输入图像
cv::Mat src;
cap >> src; // 获取新的一帧
if (src.empty())
{
std::cerr << "Warning: Couldn't read a frame from the camera." << std::endl;
continue;
}
// 转换为灰度图像
cv::Mat gray;
cv::cvtColor(src, gray, cv::COLOR_BGR2GRAY);
// 高斯模糊降噪
cv::GaussianBlur(gray, gray, cv::Size(5, 5), 0);
// 圆检测(霍夫圆变换)
std::vector<cv::Vec3f> circles;
cv::HoughCircles(gray, circles, cv::HOUGH_GRADIENT, 1, gray.rows / 16, 100, 30, 1, 300);
for (const cv::Vec3f &circle : circles)
{
cv::Point center(cvRound(circle[0]), cvRound(circle[1]));
int radius = cvRound(circle[2]);
cv::circle(src, center, radius, cv::Scalar(0, 255, 255), 2); // 绘制圆
}
edit.Print(src);
}
cap.release();
return 0;
}
cv::cvtColor(src, gray, cv::COLOR_BGR2GRAY);
cv::Canny(gray, edges, 50, 150);
cv::HoughLinesP(edges, lines, 1, CV_PI / 180, 50, 50, 10);
for (const cv::Vec4i &line : lines)
{
cv::line(src, cv::Point(line[0], line[1]), cv::Point(line[2], line[3]), cv::Scalar(255, 0, 0), 2);
}
#include <lockzhiner_vision_module/edit/edit.h>
#include <opencv2/opencv.hpp>
#include <iostream>
int main()
{
lockzhiner_vision_module::edit::Edit edit;
if (!edit.StartAndAcceptConnection())
{
std::cerr << "Error: Failed to start and accept connection." << std::endl;
return EXIT_FAILURE;
}
std::cout << "Device connected successfully." << std::endl;
// 初始化摄像头
cv::VideoCapture cap;
int width = 640; // 设置摄像头分辨率宽度
int height = 480; // 设置摄像头分辨率高度
cap.set(cv::CAP_PROP_FRAME_WIDTH, width);
cap.set(cv::CAP_PROP_FRAME_HEIGHT, height);
cap.open(0); // 参数 0 表示默认摄像头设备
if (!cap.isOpened())
{
std::cerr << "Error: Could not open camera." << std::endl;
return EXIT_FAILURE;
}
while (true)
{
// 读取输入图像
cv::Mat src;
cap >> src; // 获取新的一帧
if (src.empty())
{
std::cerr << "Warning: Couldn't read a frame from the camera." << std::endl;
continue;
}
// 转换为灰度图像
cv::Mat gray;
cv::cvtColor(src, gray, cv::COLOR_BGR2GRAY);
// 边缘检测(Canny)
cv::Mat edges;
cv::Canny(gray, edges, 50, 150);
// 直线检测(霍夫变换)
std::vector<cv::Vec4i> lines;
cv::HoughLinesP(edges, lines, 1, CV_PI / 180, 50, 50, 10);
for (const cv::Vec4i &line : lines)
{
cv::line(src, cv::Point(line[0], line[1]), cv::Point(line[2], line[3]), cv::Scalar(255, 0, 0), 2);
}
edit.Print(src);
}
cap.release();
return 0;
}
cv::cvtColor(src, gray, cv::COLOR_BGR2GRAY);
cv::GaussianBlur(gray, gray, cv::Size(5, 5), 0);
cv::Canny(gray, edges, 50, 150);
std::vector<std::vector<cv::Point>> contours;
cv::findContours(edges, contours, cv::RETR_LIST, cv::CHAIN_APPROX_SIMPLE);
for (size_t i = 0; i < contours.size(); i++) {
std::vector<cv::Point> approx;
cv::approxPolyDP(contours[i], approx,
cv::arcLength(contours[i], true) * 0.02, true);
cv::drawContours(polygonImage,
std::vector<std::vector<cv::Point>>{approx}, -1,
cv::Scalar(0, 0, 255), 2);
}
#include <lockzhiner_vision_module/edit/edit.h>
#include <iostream>
#include <opencv2/opencv.hpp>
int main()
{
lockzhiner_vision_module::edit::Edit edit;
if (!edit.StartAndAcceptConnection())
{
std::cerr << "Error: Failed to start and accept connection." << std::endl;
return EXIT_FAILURE;
}
std::cout << "Device connected successfully." << std::endl;
// 初始化摄像头
cv::VideoCapture cap;
int width = 640; // 设置摄像头分辨率宽度
int height = 480; // 设置摄像头分辨率高度
cap.set(cv::CAP_PROP_FRAME_WIDTH, width);
cap.set(cv::CAP_PROP_FRAME_HEIGHT, height);
cap.open(0); // 参数 0 表示默认摄像头设备
if (!cap.isOpened())
{
std::cerr << "Error: Could not open camera." << std::endl;
return EXIT_FAILURE;
}
while (true)
{
// 读取输入图像
cv::Mat src;
cap >> src; // 获取新的一帧
if (src.empty())
{
std::cerr << "Warning: Couldn't read a frame from the camera."
<< std::endl;
continue;
}
// 转换为灰度图像
cv::Mat gray;
cv::cvtColor(src, gray, cv::COLOR_BGR2GRAY);
// 高斯模糊降噪
cv::GaussianBlur(gray, gray, cv::Size(5, 5), 0);
// 边缘检测(Canny)
cv::Mat edges;
cv::Canny(gray, edges, 50, 150);
// 查找轮廓
std::vector<std::vector<cv::Point>> contours;
cv::findContours(edges, contours, cv::RETR_LIST, cv::CHAIN_APPROX_SIMPLE);
// 多边形拟合
cv::Mat polygonImage = src.clone();
for (size_t i = 0; i < contours.size(); i++)
{
std::vector<cv::Point> approx;
cv::approxPolyDP(contours[i], approx,
cv::arcLength(contours[i], true) * 0.02, true);
cv::drawContours(polygonImage,
std::vector<std::vector<cv::Point>>{approx}, -1,
cv::Scalar(0, 0, 255), 2);
}
edit.Print(polygonImage);
}
cap.release();
return 0;
}
# CMake最低版本要求
cmake_minimum_required(VERSION 3.10)
project(test_find_contours)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
# 定义项目根目录路径
set(PROJECT_ROOT_PATH "${CMAKE_CURRENT_SOURCE_DIR}/../..")
message("PROJECT_ROOT_PATH = " ${PROJECT_ROOT_PATH})
include("${PROJECT_ROOT_PATH}/toolchains/arm-rockchip830-linux-uclibcgnueabihf.toolchain.cmake")
# 定义 OpenCV SDK 路径
set(OpenCV_ROOT_PATH "${PROJECT_ROOT_PATH}/third_party/opencv-mobile-4.10.0-lockzhiner-vision-module")
set(OpenCV_DIR "${OpenCV_ROOT_PATH}/lib/cmake/opencv4")
find_package(OpenCV REQUIRED)
set(OPENCV_LIBRARIES "${OpenCV_LIBS}")
# 定义 LockzhinerVisionModule SDK 路径
set(LockzhinerVisionModule_ROOT_PATH "${PROJECT_ROOT_PATH}/third_party/lockzhiner_vision_module_sdk")
set(LockzhinerVisionModule_DIR "${LockzhinerVisionModule_ROOT_PATH}/lib/cmake/lockzhiner_vision_module")
find_package(LockzhinerVisionModule REQUIRED)
# 寻找圆型轮廓
add_executable(Test-find-circle find_circle.cc)
target_include_directories(Test-find-circle PRIVATE ${LOCKZHINER_VISION_MODULE_INCLUDE_DIRS})
target_link_libraries(Test-find-circle PRIVATE ${OPENCV_LIBRARIES} ${LOCKZHINER_VISION_MODULE_LIBRARIES})
# 寻找线
add_executable(Test-find-line find_line.cc)
target_include_directories(Test-find-line PRIVATE ${LOCKZHINER_VISION_MODULE_INCLUDE_DIRS})
target_link_libraries(Test-find-line PRIVATE ${OPENCV_LIBRARIES} ${LOCKZHINER_VISION_MODULE_LIBRARIES})
# 寻找多边形
add_executable(Test-find-polygon find_polygon.cc)
target_include_directories(Test-find-polygon PRIVATE ${LOCKZHINER_VISION_MODULE_INCLUDE_DIRS})
target_link_libraries(Test-find-polygon PRIVATE ${OPENCV_LIBRARIES} ${LOCKZHINER_VISION_MODULE_LIBRARIES})
install(
TARGETS Test-find-circle
TARGETS Test-find-line
TARGETS Test-find-polygon
RUNTIME DESTINATION .
)
使用 Docker Destop 打开 LockzhinerVisionModule 容器并执行以下命令来编译项目
# 进入Demo所在目录
cd /LockzhinerVisionModuleWorkSpace/LockzhinerVisionModule/Cpp_example/C04_find_contours
# 创建编译目录
rm -rf build && mkdir build && cd build
# 配置交叉编译工具链
export TOOLCHAIN_ROOT_PATH="/LockzhinerVisionModuleWorkSpace/arm-rockchip830-linux-uclibcgnueabihf"
# 使用cmake配置项目
cmake ..
# 执行编译项目
make -j8 && make install
在执行完上述命令后,会在build目录下生成可执行文件。
chmod find_circle
./find_circle
chmod find_line
./find_line
chmod find_polygon
./find_polygon