cv::convexHull broken (Bug #3040)

Added by Hartmut Seichter almost 12 years ago. Updated over 11 years ago.

Status:Cancelled Start date:
Priority:Normal Due date:
Assignee:Hartmut Seichter % Done:

0%
Category:imgproc, video
Target version:2.4.6
Affected version:2.4.5 (latest release) Operating System:
Difficulty: HW Platform:
Pull request:

Description

Somehow convexHull doesn't produce useful results:

std::vector<cv::Point> quad(4);
points[0] = cv::Point(10,5);
points[1] = cv::Point(20,10);
points[2] = cv::Point(20,20);
points[3] = cv::Point(20,10);

std::vector<cv::Point> hull;
cv::convexHull(quad,hull,true,true);

for (int i = 0; i < hull.size();++i)
   std::cout << "Hull " << i << " " << hull.at(i) << std::endl;

produces

Hull 0 [0, 0]

Did I oversee something? Just checked the docs. Variations with Point2f or just indices also produce various random results.

Just in case: Mac OS X 10.7 Lion, clang-64

History

#1
Updated by Andrey Pavlenko almost 12 years ago

  • Start date deleted (2013-05-22)
  • Category set to imgproc, video
  • Assignee set to Vadim Pisarevsky

#2
Updated by Andrey Pavlenko over 11 years ago

  • Target version set to Next Hackathon

#3
Updated by Kirill Kornyakov over 11 years ago

deleted wrong comment

  • Assignee deleted (Vadim Pisarevsky)
  • Priority changed from High to Normal

#4
Updated by Kirill Kornyakov over 11 years ago

Can't reproduce. May be this is because you fill points vector, while processing quad? Here is my code that works:

#include <opencv2/core/core.hpp>
#include "opencv2/imgproc/imgproc.hpp" 

#include <iostream>

using namespace std;

int main ()
{
    std::vector<cv::Point> quad(4);
    quad[0] = cv::Point(10,5);
    quad[1] = cv::Point(20,10);
    quad[2] = cv::Point(20,20);
    quad[3] = cv::Point(20,10);

    std::vector<cv::Point> hull;
    cv::convexHull(quad, hull, true, true);

    for (int i = 0; i < hull.size();++i)
       std::cout << "Hull " << i << " " << hull.at(i) << std::endl;

   return 0;
}

Output:

~/Work/OpenCV/build_linux_2.4> ./bin/cpp-example-convhull 
Hull 0 [10, 5]
Hull 1 [20, 20]
Hull 2 [20, 10]

  • Assignee set to Hartmut Seichter
  • Status changed from Open to Cancelled
  • Target version changed from Next Hackathon to 2.4.6

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