Error in jaccard_index_3d when using quaternions

[samwarren]

The following code:

from bbox import BBox3D
import pyquaternion
a = BBox3D(x=0, y=0, z=0, q=pyquaternion.Quaternion(axis=[1, 0, 0], angle=3.14159265))  
 b = BBox3D(x=1, y=0, z=0, q=pyquaternion.Quaternion(axis=[1, 0, 0], angle=3.14159265))  
bbox.metrics.iou_3d(a,b)

produces the error

---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
<ipython-input-7-e3b42501e331> in <module>
----> 1 bbox.metrics.iou_3d(a,b)

~/PycharmProjects/thea_context/.venv/lib/python3.6/site-packages/bbox/metrics.py in iou_3d(a, b)
    131     Alias for `jaccard_index_3d`.
    132     """
--> 133     return jaccard_index_3d(a, b)
    134 
    135 

~/PycharmProjects/thea_context/.venv/lib/python3.6/site-packages/bbox/metrics.py in jaccard_index_3d(a, b)
    152         return np.round_(0, decimals=5)
    153 
--> 154     intersection_points = polygon_intersection(a.p[0:4, 0:2], b.p[0:4, 0:2])
    155     inter_area = polygon_area(intersection_points)
    156 

~/PycharmProjects/thea_context/.venv/lib/python3.6/site-packages/bbox/geometry.py in polygon_intersection(poly1, poly2)
    171         input_list = output_list
    172         output_list = []
--> 173         s = input_list[-1]
    174 
    175         for e in input_list:

IndexError: list index out of range

[bokunobaka]

Any luck figuring this out?

[TCherici]

It doesn't have to be related to quaternions specifically. I managed to get the same error with the following code:

from bbox import BBox3D
from bbox.metrics import iou_3d


bbox_a = BBox3D(x=332.5, y=85.0, z=205.5, length=125, width=74, height=45)
bbox_b = BBox3D(x=332.5, y=144.0, z=366.5, length=113, width=44, height=65)


iou_3d(bbox_a, bbox_b)

[varunagrawal]

Interesting. I'll look into this over the weekend.

[varunagrawal]

I finally got time to look into this and the issue seems to be that the polygon collision code for 3D boxes isn't quite correct. I'll try fixing this soon.

[varunagrawal]

Specifically, the example given here involves 2 non-overlapping boxes, so the polygon collision function is returning True when it should be returning False.

[gunnxx]

Perhaps we can use shapely to compute intersection area between two polygons. Quick example is here.

Details: Changing

intersection_points = polygon_intersection(a.p[0:4, 0:2], b.p[0:4, 0:2])
inter_area = polygon_area(intersection_points)

to

poly1 = shapely.geometry.Polygon(a.p[0:4, 0:2])
poly2 = shapely.geometry.Polygon(b.p[0:4, 0:2])
inter_area = poly1.intersection(poly2).area

However, you have to install shapely first (ie. pip install shapely)