opencv笔记三十三（判断点是否在轮廓内部）

 

pointPolygonTest(

InputArray contour,// 输入的轮廓

Point2f pt, // 测试点

bool measureDist // 是否返回距离值，如果是false，1表示在内面，0表示在边界上，-1表示在外部，true返回实际距离 )

返回数据是double类型

 

 

#include 
#include 
#include 

using namespace std;
using namespace cv;
int main(int argc, char** argv) {
	const int r = 100;
	Mat src = Mat::zeros(r * 4, r * 4, CV_8UC1);

	vector vert(6);
	vert[0] = Point(3 * r / 2, static_cast(1.34*r));   
	vert[1] = Point(1 * r, 2 * r);
	vert[2] = Point(3 * r / 2, static_cast(2.866*r));   
	vert[3] = Point(5 * r / 2, static_cast(2.866*r));
	vert[4] = Point(3 * r, 2 * r);   
	vert[5] = Point(5 * r / 2, static_cast(1.34*r));

	for (int i = 0; i < 6; i++) {
		line(src, vert[i], vert[(i + 1) % 6], Scalar(255), 3, 8, 0);
	}
	
	vector> contours;
	vector hierachy;
	Mat csrc;
	src.copyTo(csrc);
	findContours(csrc, contours, hierachy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point(0, 0));
	Mat raw_dist = Mat::zeros(csrc.size(), CV_32FC1);
	for (int row = 0; row < raw_dist.rows; row++) {
		for (int col = 0; col < raw_dist.cols; col++) {
			double dist = pointPolygonTest(contours[0],
                          Point2f(static_cast(col), 
                          static_cast(row)), true);//注意这里是col和row我也不知道Why
			raw_dist.at(row, col) = static_cast(dist);
		}
	}

	double minValue, maxValue;
	minMaxLoc(raw_dist, &minValue, &maxValue, 0, 0, Mat());
	Mat drawImg = Mat::zeros(src.size(), CV_8UC3);
	for (int row = 0; row < drawImg.rows; row++) {
		for (int col = 0; col < drawImg.cols; col++) {
			float dist = raw_dist.at(row, col);
			if (dist > 0) {
				drawImg.at(row, col)[0] = (uchar)(abs(1.0 - (dist / maxValue)) * 255);
			}
			else if (dist < 0) {
				drawImg.at(row, col)[2] = (uchar)(abs(1.0 - (dist / minValue)) * 255);
			} else {
				drawImg.at(row, col)[0] = (uchar)(abs(255 - dist));
				drawImg.at(row, col)[1] = (uchar)(abs(255 - dist));
				drawImg.at(row, col)[2] = (uchar)(abs(255 - dist));
			}
		}
	}

	const char* output_win = "point polygon test demo";
	char input_win[] = "input image";
	namedWindow(input_win, CV_WINDOW_AUTOSIZE);
	namedWindow(output_win, CV_WINDOW_AUTOSIZE);

	imshow(input_win, src);
	imshow(output_win, drawImg);

	waitKey(0);
	return 0;
}