opencv 6 图像轮廓与图像分割修复 1 查找并绘制轮廓 寻找物体的凸包
目录
查找并绘制轮廓
寻找轮廓（findContours）函数
绘制轮廓（drawContours()函数）
基础实例程序：轮廓查找
#include <opencv2/opencv.hpp>
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
using namespace cv;
using namespace std;
//-----------------------------------【main( )函数】--------------------------------------------
// 描述：控制台应用程序的入口函数，我们的程序从这里开始
//-------------------------------------------------------------------------------------------------
int main(int argc, char** argv)
{
// 【1】载入原始图，且必须以二值图模式载入
Mat srcImage = imread("1.jpg", 0);
imshow("原始图", srcImage);
//【2】初始化结果图
Mat dstImage = Mat::zeros(srcImage.rows, srcImage.cols, CV_8UC3);
//【3】srcImage取大于阈值119的那部分
srcImage = srcImage > 119;
imshow("取阈值后的原始图", srcImage);
//【4】定义轮廓和层次结构
vector<vector<Point> > contours;
vector<Vec4i> hierarchy;
//【5】查找轮廓
//此句代码的OpenCV3版为：
findContours(srcImage, contours, hierarchy, RETR_CCOMP, CHAIN_APPROX_SIMPLE);
// 【6】遍历所有顶层的轮廓， 以随机颜色绘制出每个连接组件颜色
int index = 0;
for (; index >= 0; index = hierarchy[index][0])
{
Scalar color(rand() & 255, rand() & 255, rand() & 255);
drawContours(dstImage, contours, index, color, FILLED, 8, hierarchy);
}
//【7】显示最后的轮廓图
imshow("轮廓图", dstImage);
waitKey(0);
}
综合实例程序(加blur，canny和滑动条）：
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include <iostream>
using namespace cv;
using namespace std;
//-----------------------------------【宏定义部分】--------------------------------------------
// 描述：定义一些辅助宏
//------------------------------------------------------------------------------------------------
#define WINDOW_NAME1 "【原始图窗口】" //为窗口标题定义的宏
#define WINDOW_NAME2 "【轮廓图】" //为窗口标题定义的宏
//-----------------------------------【全局变量声明部分】--------------------------------------
// 描述：全局变量的声明
//-----------------------------------------------------------------------------------------------
Mat g_srcImage;
Mat g_grayImage;
int g_nThresh = 80;
int g_nThresh_max = 255;
RNG g_rng(12345);
Mat g_cannyMat_output;
vector<vector<Point>> g_vContours;
vector<Vec4i> g_vHierarchy;
//-----------------------------------【全局函数声明部分】--------------------------------------
// 描述：全局函数的声明
//-----------------------------------------------------------------------------------------------
static void ShowHelpText();
void on_ThreshChange(int, void*);
//-----------------------------------【main( )函数】--------------------------------------------
// 描述：控制台应用程序的入口函数，我们的程序从这里开始执行
//-----------------------------------------------------------------------------------------------
int main(int argc, char** argv)
{
//【0】改变console字体颜色
system("color 1F");
//【0】显示欢迎和帮助文字
ShowHelpText();
// 加载源图像
g_srcImage = imread("1.jpg", 1);
if (!g_srcImage.data) { printf("读取图片错误，请确定目录下是否有imread函数指定的图片存在~！ \n"); return false; }
// 转成灰度并模糊化降噪
cvtColor(g_srcImage, g_grayImage, COLOR_BGR2GRAY);
blur(g_grayImage, g_grayImage, Size(3, 3));
// 创建窗口
namedWindow(WINDOW_NAME1, WINDOW_AUTOSIZE);
imshow(WINDOW_NAME1, g_srcImage);
//创建滚动条并初始化
createTrackbar("canny阈值", WINDOW_NAME1, &g_nThresh, g_nThresh_max, on_ThreshChange);
on_ThreshChange(0, 0);
waitKey(0);
return(0);
}
//-----------------------------------【on_ThreshChange( )函数】------------------------------
// 描述：回调函数
//----------------------------------------------------------------------------------------------
void on_ThreshChange(int, void*)
{
// 用Canny算子检测边缘
Canny(g_grayImage, g_cannyMat_output, g_nThresh, g_nThresh * 2, 3);
// 寻找轮廓
findContours(g_cannyMat_output, g_vContours, g_vHierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point(0, 0));
// 绘出轮廓
Mat drawing = Mat::zeros(g_cannyMat_output.size(), CV_8UC3);
for (int i = 0; i < g_vContours.size(); i++)
{
Scalar color = Scalar(g_rng.uniform(0, 255), g_rng.uniform(0, 255), g_rng.uniform(0, 255));//任意值
drawContours(drawing, g_vContours, i, color, 2, 8, g_vHierarchy, 0, Point());
}
// 显示效果图
imshow(WINDOW_NAME2, drawing);
}
//-----------------------------------【ShowHelpText( )函数】----------------------------------
// 描述：输出一些帮助信息
//----------------------------------------------------------------------------------------------
static void ShowHelpText()
{
//输出欢迎信息和OpenCV版本
printf("\n\n\t\t\t 当前使用的OpenCV版本为：" CV_VERSION);
printf("\n\n ----------------------------------------------------------------------------\n");
//输出一些帮助信息
printf("\n\n\t欢迎来到【在图形中寻找轮廓】示例程序~\n\n");
printf("\n\n\t按键操作说明: \n\n"
"\t\t键盘按键任意键- 退出程序\n\n"
"\t\t滑动滚动条-改变阈值\n");
}
寻找物体的凸包
寻找凸包（convexHull()函数）
基础示例程序：凸包检测基础
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/highgui/highgui.hpp"
#include <iostream>
using namespace cv;
using namespace std;
//-----------------------------------【ShowHelpText( )函数】----------------------------------
// 描述：输出一些帮助信息
//----------------------------------------------------------------------------------------------
static void ShowHelpText()
{
//输出欢迎信息和OpenCV版本
printf("\n\n\t\t\t 当前使用的OpenCV版本为：" CV_VERSION);
printf("\n\n ----------------------------------------------------------------------------\n");
//输出一些帮助信息
printf("\n\t欢迎来到【凸包检测】示例程序~\n\n");
printf("\n\t按键操作说明: \n\n"
"\t\t键盘按键【ESC】、【Q】、【q】- 退出程序\n\n"
"\t\t键盘按键任意键 - 重新生成随机点，并进行凸包检测\n");
}
//--------------------------------------【main( )函数】-----------------------------------------
// 描述：控制台应用程序的入口函数，我们的程序从这里开始执行
//-----------------------------------------------------------------------------------------------
int main()
{
//改变console字体颜色
system("color 1F");
//显示帮助文字
ShowHelpText();
//初始化变量和随机值
Mat image(600, 600, CV_8UC3);
RNG& rng = theRNG();
//循环，按下ESC,Q,q键程序退出，否则有键按下便一直更新
while (1)
{
//参数初始化
char key;//键值
int count = (unsigned)rng % 100 + 3;//随机生成点的数量
vector<Point> points; //点值
//随机生成点坐标
for (int i = 0; i < count; i++)
{
Point point;
point.x = rng.uniform(image.cols / 4, image.cols * 3 / 4);
point.y = rng.uniform(image.rows / 4, image.rows * 3 / 4);
points.push_back(point);
}
//检测凸包
vector<int> hull;
convexHull(Mat(points), hull, true);
//绘制出随机颜色的点
image = Scalar::all(0);
for (int i = 0; i < count; i++)
circle(image, points[i], 3, Scalar(rng.uniform(0, 255), rng.uniform(0, 255), rng.uniform(0, 255)), FILLED, LINE_AA);
//准备参数
int hullcount = (int)hull.size();//凸包的边数
Point point0 = points[hull[hullcount - 1]];//连接凸包边的坐标点
//绘制凸包的边
for (int i = 0; i < hullcount; i++)
{
Point point = points[hull[i]];
line(image, point0, point, Scalar(255, 255, 255), 2, LINE_AA);
point0 = point;
}
//显示效果图
imshow("凸包检测示例", image);
//按下ESC,Q,或者q，程序退出
key = (char)waitKey();
if (key == 27 || key == 'q' || key == 'Q')
break;
}
return 0;
}
综合实例程序：寻找和绘制物体的凸包
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include <iostream>
using namespace cv;
using namespace std;
//-----------------------------------【宏定义部分】--------------------------------------------
// 描述：定义一些辅助宏
//------------------------------------------------------------------------------------------------
#define WINDOW_NAME1 "【原始图窗口】" //为窗口标题定义的宏
#define WINDOW_NAME2 "【效果图窗口】" //为窗口标题定义的宏
//-----------------------------------【全局变量声明部分】--------------------------------------
// 描述：全局变量的声明
//-----------------------------------------------------------------------------------------------
Mat g_srcImage; Mat g_grayImage;
int g_nThresh = 50;
int g_maxThresh = 255;
RNG g_rng(12345);
Mat srcImage_copy = g_srcImage.clone();
Mat g_thresholdImage_output;
vector<vector<Point> > g_vContours;
vector<Vec4i> g_vHierarchy;
//-----------------------------------【全局函数声明部分】--------------------------------------
// 描述：全局函数的声明
//-----------------------------------------------------------------------------------------------
void on_ThreshChange(int, void*);
//-----------------------------------【main( )函数】------------------------------------------
// 描述：控制台应用程序的入口函数，我们的程序从这里开始执行
//-----------------------------------------------------------------------------------------------
int main()
{
// 加载源图像
g_srcImage = imread("1.jpg", 1);
// 将原图转换成灰度图并进行模糊降
cvtColor(g_srcImage, g_grayImage, COLOR_BGR2GRAY);
blur(g_grayImage, g_grayImage, Size(3, 3));
// 创建原图窗口并显示
namedWindow(WINDOW_NAME1, WINDOW_AUTOSIZE);
imshow(WINDOW_NAME1, g_srcImage);
//创建滚动条
createTrackbar(" 阈值:", WINDOW_NAME1, &g_nThresh, g_maxThresh, on_ThreshChange);
on_ThreshChange(0, 0);//调用一次进行初始化
waitKey(0);
return(0);
}
//-----------------------------------【thresh_callback( )函数】----------------------------------
// 描述：回调函数
//----------------------------------------------------------------------------------------------
void on_ThreshChange(int, void*)
{
// 对图像进行二值化，控制阈值
threshold(g_grayImage, g_thresholdImage_output, g_nThresh, 255, THRESH_BINARY);
// 寻找轮廓
findContours(g_thresholdImage_output, g_vContours, g_vHierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point(0, 0));
// 遍历每个轮廓，寻找其凸包
vector<vector<Point> >hull(g_vContours.size());
for (unsigned int i = 0; i < g_vContours.size(); i++)
{
convexHull(Mat(g_vContours[i]), hull[i], false);
}
// 绘出轮廓及其凸包
Mat drawing = Mat::zeros(g_thresholdImage_output.size(), CV_8UC3);
for (unsigned int i = 0; i < g_vContours.size(); i++)
{
Scalar color = Scalar(g_rng.uniform(0, 255), g_rng.uniform(0, 255), g_rng.uniform(0, 255));
drawContours(drawing, g_vContours, i, color, 1, 8, vector<Vec4i>(), 0, Point());
drawContours(drawing, hull, i, color, 1, 8, vector<Vec4i>(), 0, Point());
}
// 显示效果图
imshow(WINDOW_NAME2, drawing);
}
HSV学习链接https://blog.csdn.net/coldwindha/article/details/82080176
