我正在为 OpenCV2 和 C++ 编写一些示例代码，但我被卡住了。编译器（Win7 上的 MinGW，g++ 4.7.2）说重载 'Point_(cv::Point2f&)' 的调用是模棱两可的，但我找不到确切的问题所在。这是错误：
18:09:33 **** Incremental Build of configuration Debug for project Blobs ****
Info: Internal Builder is used for build
g++ "-IC:\\OpenCV246PC\\build\\include" -O0 -g3 -Wall -c -fmessage-length=0 -o blobs.o "..\\blobs.cpp"
..\blobs.cpp: In function ‘int main()’:
..\blobs.cpp:65:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
..\blobs.cpp:65:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
..\blobs.cpp:99:37: error: call of overloaded ‘Point_(cv::Point2f&)’ is ambiguous
..\blobs.cpp:99:37: note: candidates are:
In file included from ..\blobs.cpp:20:0:
C:\OpenCV246PC\build\include/opencv2/core/core.hpp:740:5: note: cv::Point_<_Tp>::Point_(const CvPoint2D32f&) [with _Tp = int; CvPoint2D32f = CvPoint2D32f]
C:\OpenCV246PC\build\include/opencv2/core/core.hpp:739:5: note: cv::Point_<_Tp>::Point_(const CvPoint&) [with _Tp = int; CvPoint = CvPoint]
C:\OpenCV246PC\build\include/opencv2/core/core.hpp:738:5: note: cv::Point_<_Tp>::Point_(const cv::Point_<_Tp>&) [with _Tp = int; cv::Point_<_Tp> = cv::Point_<int>]
// ERROR IS HERE
// It god mixed up when I pasted, so line number is not the one compiler complains.
cv::circle(result, cv::Point(center), static_cast<int>(radius), cv::Scalar(0), 2);
这是代码：
#include <iostream>
#include <vector>
#include <opencv2/core/core.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/highgui/highgui.hpp>
int main()
{
// Read input binary image
cv::Mat image = cv::imread("binaryGroup.bmp", 0);
if (!image.data)
return 0;
cv::namedWindow("Binary Image");
cv::imshow("Binary Image", image);
// Get the contours of the connected components
std::vector<std::vector<cv::Point> > contours;
cv::findContours(image, contours, // a vector of contours
CV_RETR_EXTERNAL, // retrieve the external contours
CV_CHAIN_APPROX_NONE); // retrieve all pixels of each contours
// Print contours' length
std::cout << "Contours: " << contours.size() << std::endl;
std::vector<std::vector<cv::Point> >::const_iterator itContours = contours.begin();
for (; itContours != contours.end(); ++itContours)
{
std::cout << "Size: " << itContours->size() << std::endl;
}
// draw black contours on white image
cv::Mat result(image.size(), CV_8U, cv::Scalar(255));
cv::drawContours(result, contours, -1, // draw all contours
cv::Scalar(0), // in black
2); // with a thickness of 2
cv::namedWindow("Contours");
cv::imshow("Contours", result);
// Eliminate too short or too long contours
int cmin = 100; // minimum contour length
int cmax = 1000; // maximum contour length
std::vector<std::vector<cv::Point> >::iterator itc = contours.begin();
while (itc != contours.end())
{
if (itc->size() < cmin || itc->size() > cmax)
itc = contours.erase(itc);
else
++itc;
}
// draw contours on the original image
cv::Mat original = cv::imread("group.jpg");
cv::drawContours(original, contours, -1, // draw all contours
cv::Scalar(255, 255, 255), // in white
2); // with a thickness of 2
cv::namedWindow("Contours on Animals");
cv::imshow("Contours on Animals", original);
// Let's now draw black contours on white image
result.setTo(cv::Scalar(255));
cv::drawContours(result, contours, -1, // draw all contours
cv::Scalar(0), // in black
1); // with a thickness of 1
image = cv::imread("binaryGroup.bmp", 0);
// testing the bounding box
cv::Rect r0 = cv::boundingRect(cv::Mat(contours[0]));
cv::rectangle(result, r0, cv::Scalar(0), 2);
// testing the enclosing circle
float radius;
cv::Point2f center;
// http://opencv.willowgarage.com/documentation/cpp/structural_analysis_and_shape_descriptors.html#cv-minenclosingcircle
// void minEnclosingCircle(const Mat& points, Point2f& center, float& radius)
cv::minEnclosingCircle(cv::Mat(contours[1]), center, radius);
// http://opencv.willowgarage.com/documentation/cpp/drawing_functions.html#cv-circle
// void circle(Mat& img, Point center, int radius, const Scalar& color, int thickness=1, int lineType=8, int shift=0)
// ERROR IS HERE
cv::circle(result, cv::Point(center), static_cast<int>(radius), cv::Scalar(0), 2); // <--- ERROR IS HERE
// cv::RotatedRect rrect= cv::fitEllipse(cv::Mat(contours[1]));
// cv::ellipse(result,rrect,cv::Scalar(0),2);
// testing the approximate polygon
std::vector<cv::Point> poly;
cv::approxPolyDP(cv::Mat(contours[2]), poly, 5, true);
std::cout << "Polygon size: " << poly.size() << std::endl;
// Iterate over each segment and draw it
std::vector<cv::Point>::const_iterator itp = poly.begin();
while (itp != (poly.end() - 1))
{
cv::line(result, *itp, *(itp + 1), cv::Scalar(0), 2);
++itp;
}
// last point linked to first point
cv::line(result, *(poly.begin()), *(poly.end() - 1), cv::Scalar(20), 2);
// testing the convex hull
std::vector<cv::Point> hull;
cv::convexHull(cv::Mat(contours[3]), hull);
// Iterate over each segment and draw it
std::vector<cv::Point>::const_iterator it = hull.begin();
while (it != (hull.end() - 1))
{
cv::line(result, *it, *(it + 1), cv::Scalar(0), 2);
++it;
}
// last point linked to first point
cv::line(result, *(hull.begin()), *(hull.end() - 1), cv::Scalar(20), 2);
// testing the moments
// iterate over all contours
itc = contours.begin();
while (itc != contours.end())
{
// compute all moments
cv::Moments mom = cv::moments(cv::Mat(*itc++));
// draw mass center
cv::circle(result,
// position of mass center converted to integer
cv::Point(mom.m10 / mom.m00, mom.m01 / mom.m00), 2, cv::Scalar(0), 2); // draw black dot
}
cv::namedWindow("Some Shape descriptors");
cv::imshow("Some Shape descriptors", result);
// New call to findContours but with CV_RETR_LIST flag
image = cv::imread("binaryGroup.bmp", 0);
// Get the contours of the connected components
cv::findContours(image, contours, // a vector of contours
CV_RETR_LIST, // retrieve the external and internal contours
CV_CHAIN_APPROX_NONE); // retrieve all pixels of each contours
// draw black contours on white image
result.setTo(cv::Scalar(255));
cv::drawContours(result, contours, -1, // draw all contours
cv::Scalar(0), // in black
2); // with a thickness of 2
cv::namedWindow("All Contours");
cv::imshow("All Contours", result);
cv::waitKey();
return 0;
}
我做错了什么？
编辑：我希望一些投反对票的人尝试解决这个问题。这不是这种类型的唯一问题，但我的已经被否决了 3 次？
此外，这是来自加拿大教授（ http://www.laganiere.name/opencvCookbook/ ）的书中的示例，他同时教授 OpenCV，我应该比他更好吗？我应该为我问这个感到羞耻吗？我是 C++ 和 OpenCV 的新手？我是否应该在其他十个论坛上提问，然后只有在 Stackoverflow 上找不到答案时才提问？
此外，我并不懒惰，我通过重写他的代码来帮助这个人（OpenCV：在一个窗口中录制镜头并在第二个窗口中显示相同的视频，但仅包含轮廓）。我帮助了一个比我了解少的人。但是，在这种情况下，我只是不知道如何在这段代码中解决这个问题，但在 30 分钟内我得到了三个反对票？
更新：正如 OpenCV 社区向我指出的那样，实际上应该允许将 Point 转换为 Point2f，反之亦然，但是版本 2.4.3 中的错误（http://code.opencv.org/issues/2616#note-1）阻止它这样做。这就解释了为什么几年前这段代码是为原作者编译的，而不是为我编译的。无论如何，用户@alrikai 为此提供了正确的答案和解决方法。
错误更正为：cv::circle(result, cv::Point2f(center), static_cast(radius), cv::Scalar(0), 2); 所以 cv::Point(center) 变成了这个 cv::Point2f(center)