图像分割与轮廓的绘制 图像分割概述

今天练习了简单的图像分割与轮廓的绘制，以及在轮廓内的分量分析.

画出所有的轮廓出来

Mat src_img = imread(path);
Mat gray_img;
Mat bin_img;
cvtColor(src_img, gray_img, COLOR_BGR2GRAY);

灰度均值

Scalar gray_mean = mean(gray_img);
cout << gray_mean(0);
threshold(gray_img, bin_img, 90, 255, THRESH_BINARY);
寻找全部轮廓
vector<vector<Point>>contours;
vector<Vec4i>hierarchy;
findContours(bin_img, contours, hierarchy, RETR_CCOMP, CHAIN_APPROX_SIMPLE);
for (int i = 0; i < hierarchy.size(); i++)
{
Scalar color = Scalar(rand() % 255, rand() % 255, rand() % 255);
drawContours(src_img, contours, i, color,5, 8, hierarchy);
}
从所有的轮廓中找到寻找最大轮廓
double maxarea = 0;
int maxAreaIdx = 0;
for (int index = contours.size() - 1; index >= 0; index--)
{
double tmparea = fabs(contourArea(contours[index]));
if (tmparea > maxarea)
{
maxarea = tmparea;
maxAreaIdx = index;//记录最大轮廓的索引号
}
}
//Scalar color = Scalar(rand() % 255, rand() % 255, rand() % 255);
//drawContours(src_img, contours, maxAreaIdx, color, 5, 8, hierarchy);

求出最大轮廓的内切圆，这样更加精确的bgr分量进行分析。

Rect r = boundingRect(contours[maxAreaIdx]);
int nL = r.x, nR = r.br().x; //轮廓左右边界
int nT = r.y, nB = r.br().y; //轮廓上下边界
int dist = 0;
int maxdist = 0;
Point center1;
for (int i = nL; i < nR; i++) //列
{
for (int j = nT; j < nB; j++) //行
{
//计算轮廓内部各点到最近轮廓点的距离
dist = pointPolygonTest(contours[maxAreaIdx], Point(i, j), true);
if (dist > maxdist)
{
//求最大距离，只有轮廓最中心的点才距离最大
maxdist = dist;
center1 = Point(i, j);
}
}
}
int radius = maxdist; //圆半径
Point center = center1;
circle(src_img, center1 , radius, Scalar(0, 0, 0), 3, 8);

//

int point_idx_b_sum = 0;
int point_idx_g_sum = 0;
int point_idx_r_sum = 0;
vector<int> b_vec;
vector<int> g_vec;
vector<int> r_vec;
for (int i = nL; i < nR; i++) //列
{
for (int j = nT; j < nB; j++) //行
{
//计算轮廓内部各点到最近轮廓点的距离
dist = pointPolygonTest(contours[maxAreaIdx], Point(i, j), true);
b_vec.push_back(src_img.at<Vec3b>(Point(i, j))[0]);
g_vec.push_back(src_img.at<Vec3b>(Point(i, j))[1]);
r_vec.push_back(src_img.at<Vec3b>(Point(i, j))[2]);
//printf("b=%d\t", src_img.at<Vec3b>(Point(i, j))[0]);
}
}
//cout << b_vec.size();
for (vector<int>::iterator iter = b_vec.begin(); iter != b_vec.end(); iter++)
{
point_idx_b_sum = point_idx_b_sum + *iter;
}
for (vector<int>::iterator iter = g_vec.begin(); iter != g_vec.end(); iter++)
{
point_idx_g_sum = point_idx_g_sum + *iter;
}
for (vector<int>::iterator iter = r_vec.begin(); iter != r_vec.end(); iter++)
{
point_idx_r_sum = point_idx_r_sum + *iter;
}
cout << path << " " << "b=" << point_idx_b_sum / b_vec.size() << endl;
cout << path << " " << "g=" << point_idx_g_sum / b_vec.size() << endl;
cout << path << " " << "r=" << point_idx_r_sum / b_vec.size();
}

输出结果