Convex-hull of a set of points X in a Euclidean space is the convex set with smallest area that contains all points of X.
Questions tagged [convex-hull]
538 questions
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Unexpected behaviour of convex hull algorithm
I was trying to implement the algorithm to get the convex hull for a given set of points and visualise the result using opencv using the following code on c++:
#include "opencv2/opencv.hpp"
#include "StdAfx.h"
#include
#include…
user2131678
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Convex hull - Monotone chain algorithm error
I'm using the Monotone chain algorithm to create a convex hull around a set of polygons. It works well sometimes, but on some shapes, it fails. Take a look at this example:
https://i.stack.imgur.com/wfVJN.png
To the left is the shape before applying…
Eric
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Creating many convex hulls MATLAB
i'm new here and this is my first post.. i want to know if there is a way to calculate all the possible convex hulls from 100 random points.. i've created a code that does this right but it gives me an error at convhull and everything beneath that…
co2ark5
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How can i calculate elongation of a convex hull in opencv?
I have found this way to calculate elongation basing on image moments
#ELONGATION
def elongation(m):
x = m['mu20'] + m['mu02']
y = 4 * m['mu11']**2 + (m['mu20'] - m['mu02'])**2
return (x + y**0.5) / (x - y**0.5)
mom =…
postgres
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Algorithm to partition an area - find points close to each other
Is there an algorithm to find all points with a set distance from each other ? Or all rectangles that are touching ?
I divide the plane (in lat/lon coordinate system, of certain limits) in sample rectangles of n x n, and each rectangle gets a value…
Thalia
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dynamic programming optimizaton,convex hull
There is a problem asked in contest. I already solved this problem with dynamic programming and its complexity O(n^2).But i am looking more efficient way. I already saw that dynamic Programming can be optimized with convex hull. Do you have any…
sekogs
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matlab convhulln issue
Using matlab's "convhulln" (3D), my code sometimes crashes complaining of "initial facet 1 coplanar with the interior". This is correct when I inspect the shape of the object visually. But could I somehow check for this before using convhulln on the…
user1641496
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voxels inside a 3D convexhull
I have a cubic matrix of voxels of value 1 (the rest is 0). I need a matrix of the same size where the voxels INSIDE the convex hull are all of value 1. I've seen a similar example and adapted it: If I do this to the following, would that work?
%…
mickmengucci
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number of holes in convex hull in matlab
I have used convhulln in matlab to find the surrounding shape of a set of data points in 3D. See history in:
Convhull in Matlab.
A good samaritan helped me to find out how it works in matlab. I need to know the propertion of gaps (holes) inside the…
user1641496
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Drawing circles at BENDING points of convex hull
I am trying to figure out of drawing circles at the BENDING points of a convex hull. Using the sample from OpenCV documentation for convex hull , I have a convex hull. But I am not really sure on how to draw the circles at the points where the…
user349026
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What algorithm does the convhull() function in Matlab use?
What algorithms do the convhull and convhulln functions in MATLAB implement to compute the convex hull?
I cannot find any references..
Quanyi Mo
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How can extract points which are formed a convex hull of 3 dimensions polygon in Matlab by using convexhull functions?
I use different convex hull functions in Matlab to find points coordinates which are formed the convex hull. however, these functions return the matrix of triangles.
How can I specify those points?
Thanks.
Sepideh
Sepideh
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OpenCV C++ cv::convexityDefects error
vector hull;
vector defects;
convexHull(Mat(largest),hull,false);
convexityDefects(largest,hull,defects);
*largest is my largest contour in the image
But the convexityDefects gives me this error "Assertion failed (hull.checkVector(1,…
XterNalz
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Unity3D - Order list by angle to point
I am trying to make a 2D game in unity. I want to create a convex hull around a group of rigidbody2Ds that I have in a List. To do this, I need to order the List by the angle that each rigidbody2D makes with the start position. Anyone know how I…
flibit
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Why Andrew's Monotone Algorithm takes O(N LogN) times?
Andrew's monotone chain convex hull algorithm constructs the convex hull of a set of 2-dimensional points in O(n\log n) time.
I followed the steps of the algorithm and found out that it has O(n Logn) time complexity. Sorting is just finding the…
jay jay
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