Opencv Join bounding boxes python

Question

i have a haar detection and it produces me some nearby detections:

[[ 31  85 232 116]
 [141  55  66  33]
 [112  41 104  52]]

each list have the following values: x,y,w,h id like to get the most left top X,Y and the most right bottom x,y of all detections.

i tryed to use min() and max() but ot produces a error. and after that i tryed to use Numpy and i canot make what i need

import numpy as np
l = [10, 22, 8, 8, 11]
print(np.argmax(l))
print(np.argmin(l))

in my problen the list should be the list of lists and i want to get only lesser x,y and higer x,y

Equinox · Accepted Answer · 2020-12-12 19:02:43Z

1

x = [ [ 31,85,232,116],
 [141,55,66,33],
 [112,41,104,52]
]

You can use a custom key with the values of first 2 elements to get max and min value. Since you need to draw a bounding box around all boundingboxes, you need to find min of x,y pair and max of x+w,y+h pair

This assumes x,y values are always positive which is fine in a image scenario.

min(x,key=lambda x:(x[0],x[1]))[:2]
max([(e[0]+e[2],e[1]+e[3]) for e in x ])

Out:

[31, 85]
(263, 201)

edited Dec 12, 2020 at 19:02

answered Dec 12, 2020 at 17:25

Equinox

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5 Comments

Jasar Orion Over a year ago

i need the following output: (x1: 31,y1:41, x2:141, y2:85)

Equinox Over a year ago

So it's like min of 1st value, min of 2nd value and max of 1st ,max of 2nd ?

Jasar Orion Over a year ago

i need to draw a bounding box arround all boundingboxes returned in my detection

Equinox Over a year ago

then shouldn't the answer be 31,85 and (263, 201)? the lowest x y and the highest x+w,y+h

Equinox Over a year ago

Updated my answer let me know if that is what you are looking for

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