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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OpenMP C program run slower than sequential code
I am a newbie to OpenMP, trying to parallelize Jarvis's algorithm. However it turns out that the parallel program take 2-3 times longer compare to sequential code.
Is it that the problem itself cannot be parallelize? Or there is something wrong in…
Yeoh FS
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Eccentricity of a 2D convex hull in Python
How can I calculate the eccentricity of a 2D convex hull in Python?
Eccentricity: a parameter of an ellipse (or a closed shape) indicating its deviation from the circularity whose value ranging from 0 (circle) to 1 (line).
Gursel Karacor
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How to extract digit in image that overide rect area
Now, I have a project that use image processing about detect digit but I don't know how to extract when digit override the rect area.
Here's the input:
I want to get something like the bottom pictures:
rocky king
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Does there exist any linear time example for quick hull algorithm?
Suppose, the convex hull is a triangle and all the nonextreme points are interior to the triangle then is it possible that quick hull runs in linear time?
emon voxed
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Data Structure - Diameter of Polygon
I need a data structute that allows
addPoint(x, y) in O(logN)
printDiameter() in O(logN)
where N is the current number of points in the polygon.
Obviously the two points will lie on the convex hull of the polygon. Using concept of anti-nodal…
maverick
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Inflating a 2D or 3D convex hull
With the final goal of finding intersection between objects, we need to inflate their convex hulls of a small amount to check intersection even on adjacent objects.
Does a practical approach to inflate convex hulls exists?
Thanks.
abenci
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How to create arcs on boundary points of voronoi?
I am writing some 2D graphic software. And in my project i used Voronoi algorithm. And result is correct as I expected (Pic 1). Then i want to add some feature on boundary points just like (Pic 2). So i think i need to implement Concave hull on…
Edmon
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Determine whether a point lies in a convex hull in O(log n) time
I've researched several algorithms for determining whether a point lies in a convex hull, but I can't seem to find any algorithm which can do the trick in O(logn) time, nor can I come up with one myself.Let a[] be an array containing the vertices of…
Andrew Brick
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Convhull in Matlab
I have 3 vectors of position data : x, y and z
x = [0.1524 0.1219 0.0610 0.0914 0.0610 0.1219 0.0305 0.0914 0.2134 0.0610 0.1219
0.0305 0.0610 0.1219 0.0914 0.1524 0.0610 0.1524 0.0610 0.0610 0.0610 0.0610
0.1524 0.0914 0.0610 0.1524 0.0610 0.2134…
user1641496
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Convex Hull reading XY co-ords in Python
I need to come up with a convex hull algorithm to read through a bunch of X , Y co-ordinates and outline the image..
i'm coding in python
Any ideas?
Tara
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How to get all points constituting convex hull,if convex hull is perfect rectangle(python 3)?
open image to see result of below code
import numpy as np
from scipy.spatial import ConvexHull
import matplotlib.pyplot as plt
points = np.array([[1,1],[1,2],[1,3],[1,4],[2,1],[2,2],[2,3],[2,4],[3,1],[3,2],[3,3],[3,4],[4,1],[4,2],[4,3],[4,4]]) …
Sanket Chafle
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Convex hull with constant size or triangular form
I know QuickHull algorithm runs in Theta(n), if convex hull is triangular or it has constant size.
What's this means?
I'm not sure about the shape (if it looks a triangle), because the algorithm uses 4 extreme points.
Thanks
Nelson A. Morais
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passing array through convex hull
I have the following code for my convex hull:
The first section sorts the array by value of X which is required for convex hull, the second part is the actual convex hull code we were given, how do i get my array to pass through the convex hull…
user3357649
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