Test polygon point
test at a given point is inside the polygon, the outer edge or
Double pointPolygonTest ( InputArray Contour, // contour input Point2f Pt, // test point BOOL measureDist // whether the return distance value, if it is false, 1 indicates the inner surface at the boundary represents 0, -1 means the outside, true return actual distance )
The step of constructing a 400x400 size image, Mat :: Zero ( 400 , 400 , CV_8UC1) draw a line closed region hexagonal spot contour After all pixels in the image polygons to do test, to give the distance, normalized display.
int main(int argc, char** argv) { const int r = 100; Mat src = Mat::zeros(r * 4, r * 4, CV_8UC1); vector<Point2f> vert(6); vert[0] = Point(3 * r / 2, static_cast<int>(1.34*r)); vert[1] = Point(1 * r, 2 * r); vert[2] = Point(3 * r / 2, static_cast<int>(2.866*r)); vert[3] = Point(5 * r / 2, static_cast<int>(2.866*r)); vert[4] = Point(3 * r, 2 * r); vert[5] = Point(5 * r / 2, static_cast<int>(1.34*r)); for (int i = 0; i < 6; i++) { line(src, vert[i], vert[(i + 1) % 6], Scalar(255), 3, 8, 0); } // 画一个六边型 imshow("input_win", src); vector<vector<Point>> contours; vector<Vec4i> hierachy; Mat csrc; src.copyTo(csrc); //边界发现 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<float>(col), static_cast<float>(row)), true); raw_dist.at<float>(row, col) = static_cast<float>(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<float>(row, col); if (dist > 0) { //内部 drawImg.at<Vec3b>(row, col)[0] = (uchar)(abs(1.0 - (dist / maxValue)) * 255); } else if (dist < 0) { //外部 drawImg.at<Vec3b>(row, col)[2] = (uchar)(abs(1.0 - (dist / minValue)) * 255); } else { //边缘 drawImg.at<Vec3b>(row, col)[0] = (uchar)(abs(255 - dist)); drawImg.at<Vec3b>(row, col)[1] = (uchar)(abs(255 - dist)); drawImg.at<Vec3b>(row, col)[2] = (uchar)(abs(255 - dist)); } } } imshow("output_win", drawImg); waitKey(0); return 0; }